MAX20461ATJA [MAXIM]
Automotive High-Current Step-Down Converter with USB-C Protection/Host Charger;
| 型号： | MAX20461ATJA |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Automotive High-Current Step-Down Converter with USB-C Protection/Host Charger |
| 文件： | 总65页 (文件大小：1273K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
EVALUATION KIT AVAILABLE
Click here to ask about the production status of specific part numbers.
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
General Description
Benefits and Features
The MAX20461 combines a 3A high-efficiency, automo-
tive-grade, step-down converter, a USB Type-C/BC1.2
host charger emulator, and high bandwidth USB protec-
tion switches for automotive USB 2.0 host applications.
The device also includes a USB load current-sense am-
plifier and a configurable feedback-adjustment circuit that
provides automatic USB voltage compensation for voltage
drops in captive cables often found in automotive applica-
tions. The device limits the USB load current using both
a fixed internal peak-current threshold and a user-config-
urable external current-sense USB load threshold.
● One-Chip Type-C Solution Directly from Car Battery to
Portable Device
• MAX20461: USB Type-C Compliant DFP Controller
with V
Protection
CONN
• MAX20461A: USB Type-C Compliant DFP
Controller
• 1GHz Bandwidth USB 2.0 Data Switches
• 4.5V to 28V Input (40V Load Dump), Synchronous
Buck Converter
• 5V to 7V, 3A Output Capability
● Optimal USB Charging and Communication for
Portable Devices
The MAX20461 is optimized for high-frequency operation
and includes programmable frequency selection from
310kHz to 2.2MHz, allowing optimization of efficiency,
noise, and board space based on the application require-
ments. The fully synchronous DC-DC converter integrates
high-side and low-side MOSFETs with an external SYNC
input/output, and can be configured for spread-spectrum
operation.
• User-Programmable Voltage Gain Adjusts Output
for Up to 474mΩ Cable Resistance
• User-Programmable USB Current Limit
• Type-C Cable Orientation Indicator for USB3
Applications
• Supports USB BC1.2 CDP and SDP Modes
• Compatible with USB On-the-Go Specification and
Apple CarPlay®
The MAX20461 allows flexible configuration and ad-
vanced diagnostic options for both stand-alone and super-
vised applications The device can be programmed using
● Low-Noise Features Prevent Interference with AM
Band and Portable Devices
2
either external programming resistors and/or internal I C
• Fixed-Frequency 310kHz to 2.2MHz Operation
• Fixed-PWM Option at No Load
2
registers via the I C bus.
• Spread Spectrum for EMI Reduction
• SYNC Input/Output for Frequency Parking
The MAX20461 is available in a small 5mm x 5mm 32-pin
TQFN package and is designed to minimize required ex-
ternal components and layout area.
● Robust Design Keeps Vehicle System and Portable
Device Safe in an Automotive Environment
• Short-to-Battery Protection on VBUS, HVD± Pins
• CC1 and CC2 Tolerant to 20V Transients
• Advanced Diagnostics Through I C Bus
• ±25kV Air/±8kV Contact ISO 10605 (330pF, 2kΩ)*
• ±15kV Air/±8kV Contact ISO 10605 (330pF, 2kΩ)**
• ±15kV Air/±8kV Contact ISO 10605 (330pF, 330Ω)*
• ±15kV Air/±8kV Contact IEC 61000-4-2 (150pF,
330Ω)*
Applications
● Automotive Radio and Navigation
● USB Port for Host and Hub Applications
● Automotive Connectivity/Telematics
2
• Overtemperature Protection, Warning, and
Intelligent Current Foldback
• -40°C to +125°C Operating Temperature Range
*Tested in Typical Application Circuit as used on the
MAX20461 Evaluation Kit with 1m captive cable.
**Tested in Typical Application Circuit as used on the
MAX20461 Evaluation Kit without 1m captive cable.
Ordering Information appears at end of datasheet.
Apple and CarPlay are registered trademarks of Apple Inc.
19-100338; Rev 4; 12/20
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
Simplified Block Diagram
CAPTIVE
CABLE
RADIO
HEAD
MAX20461
DC-DC +
USB TYPE-C
VBAT
VBUS
D-
HVD-
HVD+
CC
PORTABLE
DEVICE
USB TYPE-C
CONNECTOR
USB
PHY
D+
VCONN
CAPTIVE
CABLE
RADIO
HEAD
MAX20461A
DC-DC +
USB TYPE-C
VBAT
VBUS
D-
HVD-
HVD+
CC
PORTABLE
DEVICE
USB TYPE-C
CONNECTOR
USB
PHY
D+
www.maximintegrated.com
Maxim Integrated | 2
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
TABLE OF CONTENTS
General Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Benefits and Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Simplified Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Absolute Maximum Ratings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Package Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
32 Pin TQFN 5x5x0.75mm. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Typical Operating Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Pin Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
MAX20461 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
MAX20461A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Pin Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Functional Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
On-Channel -3dB Bandwidth and Crosstalk. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
On-Capacitance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
DCDC_ON Reset Behavior and Timing Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
ADC Timing Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
ATTACH Logic Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Cable Attach-Detach and SENSN Discharge Timing Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Detailed Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Detailed Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
USB Type-C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Configuration Channel (CC1 and CC2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
CC Polarity Output Pin (CC_POL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
V
V
(MAX20461 Only). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
CONN
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
BUS
External FET Gate Drive (G_DMOS Pin) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Legacy Devices. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Power-Up and Enabling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
System Enable (HVEN). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
DC-DC Enable (ENBUCK) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
3.3V Input (IN). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Linear Regulator Output (BIAS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Power-On Sequencing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Step-Down DC-DC Regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Step-Down Regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Wide Input Voltage Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
www.maximintegrated.com
Maxim Integrated | 3
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
TABLE OF CONTENTS (CONTINUED)
Maximum Duty-Cycle Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Output Voltage (SENSP). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Soft-Start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Reset Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Reset Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Switching Frequency Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Switching Frequency Synchronization (SYNC Pin) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Forced-PWM Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Intelligent Skip-Mode Operation and Attach Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Spread-Spectrum Option. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Current Limit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Output Short-Circuit Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Thermal Overload Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Pre-Thermal Overload Warning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Automatic Thermal Foldback. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
USB Current Limit and Output Voltage Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Current-Sense Amplifier (SENSP, SENSN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
USB DC Current Limit Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Voltage Feedback Adjustment Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Remote Sense Feedback Adjustment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
High Voltage Modes Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
USB Protection Switches and BC1.2 Host Charger Emulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
USB Protection Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
USB Host Charger Emulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
USB On-The-Go and Dual-Role Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
2
I C, Control, and Diagnostics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
2
2
I C Configuration (CONFIG1 and I C) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Stand-Alone Configuration (CONFIG1–CONFIG3). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
2
I C Diagnostics and Event Handling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Interrupt and Attach Output (INT(ATTACH)). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
2
I C Output Voltage and Current Measurement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
2
I C Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Bit Transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
STOP and START Conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Early STOP Condition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Clock Stretching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
2
I C General Call Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
2
I C Slave Addressing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
www.maximintegrated.com
Maxim Integrated | 4
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
TABLE OF CONTENTS (CONTINUED)
Acknowledge. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Write Data Format. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Read Data Format. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Fault Detection and Diagnostics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Fault Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Fault Output Pin (FAULT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Register Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Summary Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Register Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Applications Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
DC-DC Switching Frequency Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
DC-DC Input Capacitor Selection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
DC-DC Output Capacitor Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
DC-DC Output Inductor Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Layout Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Determining USB System Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
USB Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
USB Output Current Limit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
USB Voltage Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Tuning of USB Data Lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
USB Data Line Common-Mode Choke Placement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
ESD Protection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
ESD Test Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Human Body Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
IEC 61000-4-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Typical Application Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Typical Application Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
www.maximintegrated.com
Maxim Integrated | 5
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
LIST OF FIGURES
Figure 1. Type-C Pullup Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Figure 2. USB Type-C Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Figure 3. Remote Cable-Sense Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Figure 4. Data Switch and Charge-Detection Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
2
Figure 5. I C Timing Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Figure 6. START, STOP and REPEATED START Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Figure 7. Acknowledge Condition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
2
Figure 8. Data Format of I C Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Figure 9. DC Voltage Adjustment Model. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Figure 10. Increase in SENSP vs. USB Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Figure 11. Tuning of Data Lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Figure 12. Near-Eye Diagram (with No Switch) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Figure 13. Untuned Near-Eye Diagram (with MAX20461) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Figure 14. Human Body ESD Test Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Figure 15. IEC 61000-4-2 ESD Test Model. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Figure 16. Human Body Current Waveform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Figure 17. IEC 61000-4-2 Current Waveform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
www.maximintegrated.com
Maxim Integrated | 6
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
LIST OF TABLES
Table 1. Charge Detection Precedence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Table 2. CC Pulldown Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Table 3. CC Pulldown Response (MAX20461A). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Table 4. Type-C Source V
Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
CONN
Table 5. DC-DC Converter Intelligent Skip Mode Truth Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
2
Table 6. Data Switch Mode Truth Table (I C Variant, ATJA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Table 7. Data Switch Mode Truth Table (Standalone Variant, ATJD). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
2
Table 8. CONFIG1 Pin Table (I C Version) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Table 9. CONFIG1 Pin Table (Standalone Variants) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Table 10. CONFIG2 and CONFIG3 Pin Table (Standalone Variants) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
2
Table 11. I C Slave Addresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Table 12. Fault Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Table 13. Recommended Output Filters For I
of 3A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
LOAD
www.maximintegrated.com
Maxim Integrated | 7
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
Absolute Maximum Ratings
SUPSW to PGND................................................... -0.3V to +40V
LX Continuous RMS Current .................................................3.5A
Output Short-Circuit Duration......................................Continuous
Thermal Charactaristics
HVEN to PGND ....................................... -0.3V to V
LX to PGND (Note 1)............................... -0.3V to V
SYNC to AGND ............................................-0.3V to V
+0.3V
+0.3V
+0.3V
+0.3V
SUPSW
SUPSW
Continuous Power Dissipation - Single Layer Board (T
=
BIAS
A
SENSN, SENSP, VBMON to AGND ...... -0.3V to V
+70°C, 32-TQFN (derate 21.3mW/°C above +70°C))....1702.1
mW
SUPSW
AGND to PGND..................................................... -0.3V to +0.3V
BST to PGND ........................................................ -0.3V to +46V
BST to LX ................................................................. -0.3V to +6V
IN, CONFIG1, ENBUCK, SDA (CONFIG2), SCL (CONFIG3),
BIAS, BCMODE, FAULT, CC_POL (SHIELD), CC1, CC2,
Continuous Power Dissipation - Multi Layer Board (T
=
A
+70°C, 32-TQFN (derate 34.5mW/°C above +70°C))....2758.6
mW
Operating Temperature Range .......................-40°C to +125°C
Junction Temperature ...................................................+150°C
Storage Temperature Range...........................-40°C to +150°C
Lead Temperature (soldering, 10s)...............................+300°C
Soldering Temperature (reflow).....................................+260°C
V
CONN
, INT(ATTACH) to AGND.............................. -0.3V to +6V
HVDP, HVDM to AGND.......................................... -0.3V to +18V
DP, DM to AGND..............................................-0.3V to V +0.3V
IN
G_DMOS to AGND................................................. -0.3V to +16V
Note 1: Self-protected from transient voltages exceeding these limits for ≤ 50ns in circuit under normal operation.
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the
device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for
extended periods may affect device reliability.
Package Information
32 Pin TQFN 5x5x0.75mm
Package Code
T3255+4C
21-0140
90-0012
Outline Number
Land Pattern Number
Thermal Resistance, Single-Layer Board:
Junction to Ambient (θ
)
47 °C/W
JA
Junction to Case (θ
)
1.70 °C/W
JC
Thermal Resistance, Four-Layer Board:
Junction to Ambient (θ
)
29 °C/W
JA
Junction to Case (θ
)
1.70 °C/W
JC
For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages. Note that a “+”, “#”, or “-” in the package code indicates
RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status.
Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer board. For detailed information on package thermal
considerations, refer to www.maximintegrated.com/thermal-tutorial.
www.maximintegrated.com
Maxim Integrated | 8
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
Electrical Characteristics
(V
= 14V, V = 3.3V, V
= 3.3V, V
= 5V, Temperature = T
T = -40°C to +125°C, unless otherwise noted.,
A = J
SUPSW
IN
ENBUCK
VCONN
Actual typical values may vary and are not guaranteed.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Power Supply and Enable
Supply Voltage Range
V
(Note 2)
< 1s
4.5
28
40
V
V
SUPSW
Load Dump Event
Supply Voltage Range
V
SUPSW_LD
Supply Current - Off
State
V
V
= 18V; V
= 0V, Off State
= 0V; V = 0V;
HVEN IN
SUPSW
I
I
10
1.1
1.8
20
μA
mA
mA
SUPSW
CONN
Supply Current - Buck
Off
V
HVEN
= 14V; V
= 0V
SUPSW
ENBUCK
Supply Current - Skip
Mode
I
I
V
V
= 14V; buck switching; no load
= 14V; buck switching; no load
SUPSW
HVEN
Supply Current - FPWM
BIAS Voltage
28
4.7
150
mA
V
SUPSW
HVEN
V
5.75V ≤ V
≤ 28V
SUPSW
4.5
50
5.25
3.6
BIAS
BIAS Current Limit
mA
BIAS Undervoltage
Lockout
V
V
BIAS
rising
3.0
3.3
0.2
V
V
V
V
UV_BIAS
BIAS Undervoltage
Lockout Hysteresis
SUPSW Undervoltage
Lockout
V
V
rising
3.9
4.42
UV_SUPSW
SUPSW
SUPSW Undervoltage
Lockout Hysteresis
0.2
IN Voltage Range
V
3
3.6
4.3
10
V
V
IN
IN Overvoltage Lockout
IN Input Current
V
V
V
rising
3.8
4
IN_OVLO
IN
I
µA
V
IN
HVEN Rising Threshold
HVEN Falling Threshold
HVEN Hysteresis
0.6
1.5
0.2
12
2.4
0.4
HVEN_R
V
V
HVEN_F
V
V
HVEN
HVEN Delay Rising
HVEN Delay Falling
HVEN Input Leakage
G_DMOS Pin
t
2.5
5
15
25
10
μs
μs
µA
HVEN_R
t
HVEN_F
V
V
= V
= 18V, V
= 0V
HVEN
HVEN
SUPSW
G_DMOS Unloaded
Output Voltage
to V
, internal discharge
BIAS
G_DMOS
V
7
10
100
20
13.0
250
V
G_DMOS_OC
G_DMOS_OC
G_DMOS_SC
path 2MΩ to GND
G_DMOS Output
Impedance
R
kΩ
μA
G_DMOS DC Output
Current
I
G_DMOS to BIAS
USB Type C / Power Requirements (MAX20461 Only)
VCONN Source Voltage
Input
V
1W (3.3V/305mA, 5.5V/185mA) (Note 3)
3.3
5.5
V
VCONN_IN
www.maximintegrated.com
Maxim Integrated | 9
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
Electrical Characteristics (continued)
(V
= 14V, V = 3.3V, V
= 3.3V, V
= 5V, Temperature = T
T = -40°C to +125°C, unless otherwise noted.,
A = J
SUPSW
IN
ENBUCK
VCONN
Actual typical values may vary and are not guaranteed.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Resistance from V
to CC1 and
CONN
VCONN On Resistance
R
600
1200
mΩ
ON_VCONN
CC2, V
= 5V
CONN
Measured on CC1 and CC2.
3.60V ≤ V ≤ 5.5V
VCONN Current Limit
I
310
2.2
400
2.45
3
mA
V
LIM_VCONN
CONN
VCONN UVLO
Threshold
V
VCONN_UVL
O
2.65
6.2
VCONN to CC1/CC2
Discharge Resistance
R
DCH
kΩ
USB Type C / Current Level Characteristics
CC DFP 0.5A Current
Source
I
I
I
4.0V < V
4.0V < V
4.0V < V
< 5.5V, ±20%
< 5.5V, ±8%
< 5.5V, ±8%
64
80
96
µA
µA
µA
DFP0.5_CC
DFP1.5_CC
DFP3.0_CC
BIAS
BIAS
BIAS
CC DFP 1.5A Current
Source
166
304
180
330
194
356
CC DFP 3.0A Current
Source
USB Type C / Timing Characteristics
Type-C CC Pin
Detection Debounce
t
Final transition to Attached states
160
ms
CCDEBOUNCE
DP, DM Analog USB Switches
On-Channel -3dB
Bandwidth
BW
R = R = 50Ω
1000
MHz
V
L
S
Analog Signal Range
0
3.6
4.1
Protection Trip
Threshold
V
3.65
3.85
2
V
OV_D
Protection Response
Time
V
IN
= 4.0V, V
= 3.3V to 4.3V step,
HVD±
t
µs
Ω
FP_D
R = 15kΩ on D±, delay to V < 3V
L
D±
I = 10mA, V = 0V to V , V = 3.0V
L
D±
IN IN
On-Resistance Switch A
R
4
8
ON_SA
to 3.6V
On-Resistance Match
between Channels
Switch A
∆R
I = 10mA, V = 1.5V or 3.0V
0.2
Ω
ON_SA
L
D±
On-Resistance Flatness
Switch A
R
I = 10mA,V = 0V or 0.4V
0.01
90
Ω
Ω
FLAT(ON)A
L
D_
On Resistance of
HVD+/HVD- short
R
V
V
V
V
= 1V, I
= 500μA
180
7
SHORT
DP
DM
HVD+/HVD- On-
Leakage Current
I
= 3.6V or 0V
-7
-1
µA
µA
µA
HVD_ON
HVD±
HVD±
HVD±
HVD+/HVD- Off-
Leakage Current
I
= 18V, V = 0V
150
1
HVD_OFF
D±
D+/D- Off-Leakage
Current
I
= 18V, V = 0V
D±
D_OFF
www.maximintegrated.com
Maxim Integrated | 10
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
Electrical Characteristics (continued)
(V
= 14V, V = 3.3V, V
= 3.3V, V
= 5V, Temperature = T
T = -40°C to +125°C, unless otherwise noted.,
A = J
SUPSW
IN
ENBUCK
VCONN
Actual typical values may vary and are not guaranteed.)
PARAMETER SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Current-Sense Amplifier (SENSP, SENSN) and Analog Inputs (VBMON)
10mV < V
GAIN[4:0] = 0b11111
- V
< 110mV,
SENSN
SENSP
Gain
19.4
18
V/V
mΩ
Cable Compensation
LSB
R
LSB
ILIM[2:0] = 0b111, R
ILIM[2:0] = 0b110, R
ILIM[2:0] = 0b101, R
ILIM[2:0] = 0b100, R
ILIM[2:0] = 0b011, R
ILIM[2:0] = 0b010, R
ILIM[2:0] = 0b001, R
ILIM[2:0] = 0b000, R
= 33mΩ
= 33mΩ
= 33mΩ
= 33mΩ
= 33mΩ
= 33mΩ
= 33mΩ
= 33mΩ
3.04
2.6
3.14
2.75
2.25
1.7
3.30
2.9
SENSE
SENSE
SENSE
SENSE
SENSE
SENSE
SENSE
SENSE
2.1
2.4
1.62
1.05
0.8
1.78
1.21
0.92
0.65
0.36
Overcurrent Threshold
ILIM_SET
A
1.13
0.86
0.6
0.55
0.3
0.33
SENSN / VBMON
Discharge Current
I
11
18
32
mA
ms
SENSN_DIS
Startup Wait Time
t
100
1
BUCK_WAIT
t
Discharge after POR
DCDC_ON toggle
Type-C detach
DIS_POR
s
SENSN / VBMON
Discharge Time
t
2
DIS_CD
t
100
2
ms
s
DIS_DET
BUCKOFF_CD
t
DCDC_ON toggle; see reset criteria
Type-C detach
Forced Buck Off-Time
t
BUCKOFF_DE
T
100
16
ms
Attach Comparator Load
Current Rising
Threshold
Common mode input = 5.15V
Common mode input = 5.15V
5
28
mA
Attach Comparator
Hysteresis
2.5
4.375
7.46
2
mA
V
SENSN Undervoltage
Threshold (Falling)
V
V
4
7
4.75
7.9
UV_SENSN
SENSN Overvoltage
Threshold (Rising)
V
OV_SENSN
SENSN Short Circuit
Threshold (Falling)
V
1.75
2.25
V
SHT_SENSN
SENSN Undervoltage
Fault Blanking Time
16
ms
µs
V
SENSN Overvoltage
Fault Blanking Time
From overvoltage condition to FAULT
asserted
t
3
6
B,OV_SENSN
SENSN Discharge
Threshold Falling
V
Falling
0.47
0.51
0.57
SENSN
www.maximintegrated.com
Maxim Integrated | 11
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
Electrical Characteristics (continued)
(V
= 14V, V = 3.3V, V
= 3.3V, V
= 5V, Temperature = T
T = -40°C to +125°C, unless otherwise noted.,
A = J
SUPSW
IN
ENBUCK
VCONN
Actual typical values may vary and are not guaranteed.)
PARAMETER SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Remote Feedback Adjustment
SHIELD Input Voltage
Range
0.1
0.75
V
Gain
1.935
2
2.065
V/V
mV
Input Referred Offset
Voltage
±2.0
Digital Inputs (SDA, SCL, ENBUCK, BCMODE)
Input Leakage Current
Logic High
V
PIN
= 5.5V, 0V
-5
5
µA
V
V
IH
1.6
Logic Low
V
IL
0.5
V
USB 2.0 Host Charger Emulator (HVD+/HVD-, D+/D-)
Input Logic High
Input Logic Low
Data Sink Current
V
2.0
V
V
IH
V
0.8
IL
I
V
= 0.25V to 0.4V
50
100
150
μA
DAT_SINK
DAT_SINK
Data Detect Voltage
High
V
0.4
V
V
DAT_REFH
Data Detect Voltage
Low
V
0.25
0.7
DAT_REFL
Data Detect Voltage
Hysteresis
V
60
mV
V
DAT_HYST
Data Source Voltage
V
I
= 200μA
0.5
DAT_SRC
SRC
Synchronous Step-Down DC-DC Converter
PWM Output Voltage
V
7V ≤ V
7V ≤ V
7V ≤ V
≤ 28V, No Load
5.15
5.25
V
V
SENSP
SUPSW
SUPSW
SUPSW
Skip Mode Output
Voltage
V
≤ 18V, No Load (Note 2)
≤ 18V, for 5V nominal
SENSP_SKIP
Load Regulation
R
LR
51
mΩ
V
output setting
8V ≤ V
≤ 18V, 2.4A, V
-
SENSP
SUPSW
Output Voltage
Accuracy
V
= 79.2mV , GAIN[4:0] =
6.33
1.4
6.68
SENSN
0b11111 cable compensation.
Spread Spectrum
Range
SS Enabled
±3.4
%
V
SYNC Switching
Threshold High
V
Rising
Falling
SYNC_HI
SYNC Switching
Threshold Low
V
0.4
95
V
SYNC_LO
SYNC Internal Pulldown
200
1
kΩ
SYNC Input Clock
Acquisition Time
t
(Note 4)
Cycles
SYNC
High-Side Switch On-
Resistance
R
I
LX
= 1A
54
mΩ
ONH
www.maximintegrated.com
Maxim Integrated | 12
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
Electrical Characteristics (continued)
(V
= 14V, V = 3.3V, V
= 3.3V, V
= 5V, Temperature = T
T = -40°C to +125°C, unless otherwise noted.,
A = J
SUPSW
IN
ENBUCK
VCONN
Actual typical values may vary and are not guaranteed.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
72
MAX
UNITS
mΩ
mA
Low-Side Switch On-
Resistance
R
ONL
I
= 1A
135
LX
BST Input Current
I
V
– V = 5V, High-side on
2.2
5
BST
BST
LX
LX Current-Limit
Threshold
A
Skip Mode Peak-Current
Threshold
I
1
A
SKIP_TH
Negative Current Limit
Soft-Start Ramp Time
LX Rise Time
1.2
8
A
t
ms
ns
ns
SS
(Note 4)
(Note 4)
3
LX Fall Time
4
BST Refresh Algorithm
Low-Side Minimum On-
Time
60
ns
CC_POL, FAULT, INT (ATTACH), SYNC Outputs
Output-High Leakage
Current
FAULT, INT(ATTACH), CC_POL = 5.5V
Sinking 1mA
-10
10
µA
V
Output Low Level
0.4
SYNC Output High
Level
Sourcing 1mA, SYNC configured as
output
V
BIAS
0.4
-
V
Config Resistors Converter
CONFIG1-3 Current
Leakage
V
= 0V to 4V
±5
4
µA
%
CONFIG
Minimum Window
Amplitude
-4
ADC
Resolution
ADC Gain Error
8
Bits
LSBs
LSB
±2
±1
Offset Error
Offset_ADC
Oscillators
Internal High-Frequency
Oscillator
HFOSC
7
8
9
MHz
MHz
kHz
Buck Oscillator
Frequency
f
f
FSW[2:0] = 0b000
FSW[2:0] = 0b101
1.95
340
2.2
410
2.45
480
SW
SW
Buck Oscillator
Frequency
Thermal Overload
Thermal Warning
Temperature
140
10
°C
°C
Thermal Warning
Hysteresis
www.maximintegrated.com
Maxim Integrated | 13
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
Electrical Characteristics (continued)
(V
= 14V, V = 3.3V, V
= 3.3V, V
= 5V, Temperature = T
T = -40°C to +125°C, unless otherwise noted.,
A = J
SUPSW
IN
ENBUCK
VCONN
Actual typical values may vary and are not guaranteed.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Thermal Shutdown
Temperature
165
°C
Thermal Shutdown
Hysteresis
10
°C
2
I C
Serial Clock Frequency
f
400
kHz
µs
SCL
Bus Free Time Between
STOP and START
Condition
t
1.3
BUF
START Condition Setup
Time
t
0.6
0.6
0.6
µs
µs
µs
SU:STA
HD:STA
SU:STO
START Condition Hold
Time
t
STOP Condition Setup
Time
t
Clock Low Period
Clock High Period
Data Setup Time
Data Hold Time
t
1.3
0.6
100
0.3
µs
µs
ns
µs
LOW
t
HIGH
t
SU:DAT
HD:DAT
t
From 50% SCL falling to SDA change
Human Body Model
0.6
Pulse Width of Spike
Suppressed
t
50
±2
ns
SP
ESD Protection (All Pins)
ESD Protection Level
V
kV
ESD
ESD Protection (HVDP, HVDM, CC1, CC2)
ISO 10605 Air Gap (330pF, 2kΩ)
ISO 10605 Contact (330pF, 2kΩ)
IEC 61000-4-2 Air Gap (150pF, 330Ω)
IEC 61000-4-2 Contact (150pF, 330Ω)
ISO 10605 Air-Gap (330pF, 330Ω)
ISO 10605 Contact (330pF, 330Ω)
±25
±8
±15
±8
ESD Protection Level
V
ESD
kV
±15
±8
Note 2: Device is designed for use in applications with continuous operation of 14V. Device meets electrical table up to maximum
supply voltage.
Note 3: The IR drop of the system must be considered when selecting the V
pin source voltage.
CONN
Note 4: Guaranteed by design and bench characterization; not production tested.
www.maximintegrated.com
Maxim Integrated | 14
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
Typical Operating Characteristics
(T = +25°C, unless otherwise noted.)
A
www.maximintegrated.com
Maxim Integrated | 15
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
Typical Operating Characteristics (continued)
(T = +25°C, unless otherwise noted.)
A
www.maximintegrated.com
Maxim Integrated | 16
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
Typical Operating Characteristics (continued)
(T = +25°C, unless otherwise noted.)
A
www.maximintegrated.com
Maxim Integrated | 17
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
Pin Configurations
MAX20461
TOP VIEW
24 23 22 21 20 19 18 17
25
26
27
28
29
30
31
32
16
HVEN
SDA (CONFIG2)
15
14
13
12
11
10
9
SCL (CONFIG3)
SUPSW
FAULT
SUPSW
VBMON
SENSP
SENSN
G_DMOS
BIAS
SYNC
MAX20461
INT(ATTACH)
IN
DM
DP
+
1
2
3
4
5
6
7
8
TQFN
5mm x 5mm
MAX20461A
TOP VIEW
24 23 22 21 20 19 18 17
25
26
27
28
29
30
31
32
16
15
14
13
12
11
10
9
HVEN
SDA (CONFIG2)
SCL (CONFIG3)
FAULT
SUPSW
SUPSW
VBMON
SENSP
SENSN
G_DMOS
BIAS
SYNC
MAX20461A
INT(ATTACH)
IN
DM
DP
+
1
2
3
4
5
6
7
8
TQFN
5mm x 5mm
www.maximintegrated.com
Maxim Integrated | 18
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
Pin Description
PIN
NAME
FUNCTION
MAX20461
MAX20461A
1, 5
2
1, 3, 5
AGND
CC1
Analog Ground.
2
—
4
Type-C Configuration Channel (CC).
3
VCONN
CC2
Power Source. Supplies power to the unused CC pin if required.
Type-C Configuration Channel (CC).
4
High-Voltage-Protected USB Differential Data D- Output. Connect HVD- to the
downstream USB connector D- pin.
6
7
6
7
HVDM
HVDP
High-Voltage-Protected USB Differential Data D+ Output. Connect HVD+ to the
downstream USB connector D+ pin.
CC_POL
(SHIELD)
In USB-C Configuration, CC_POL Output. In BC1.2 only variant, remote feedback
input. See Figure 3.
8
8
USB Differential Data D+ Input. Connect D+ to the low-voltage USB transceiver
D+ pin.
9
9
DP
USB Differential Data D- Input. Connect D- to the low-voltage USB transceiver D-
pin.
10
10
DM
Logic Enable Input. Connect to I/O voltage of USB transceiver. IN is also used for
clamping during overvoltage events on HVD+ or HVD-. Connect a 1µF-10µF
ceramic capacitor from IN to GND.
11
11
IN
2
INT
(ATTACH)
In the I C Variant, Functions as an Active-Low INT Pin. In the stand-alone variant,
12
13
14
15
16
17
12
13
14
15
16
17
functions as active-low attach. Connect a 100kΩ pullup resistor to IN.
Switching frequency Input/Output for synchronization with other supplies. See
Applications Information section.
SYNC
Active-low, open-drain,fault indicator output. Connect a 100kΩ pullup resistor to
the IN pin.
FAULT
2
2
SCL
(CONFIG3)
In the I C Variant, this serves as the I C SCL Pin. In stand-alone variant, this
serves as CONFIG3 pin. See Table 10.
2
2
SDA
(CONFIG2)
In the I C Variant, this serves as the I C SDA Pin. In stand-alone variant, this
serves as CONFIG2 pin. See Table 10.
This pin selects between the two modes of data switch operation. The modes are
defined in the Data Switch Mode Truth Table.
BCMODE
18
19
18
19
ENBUCK
BST
DC-DC Enable Input. Drive high/low to enable/disable the buck converter.
High-Side Driver Supply. Connect a 0.1μF capacitor from BST to LX.
Inductor connection. Connect an inductor from LX to the DC-DC converter output
(SENSP).
20, 21
22, 23
24
20, 21
22, 23
24
LX
PGND
Power Ground.
Configuration. Connect a resistor to GND to set default configuration. See Table 8
and Table 9.
CONFIG1
HVEN
25
25
Active-high system enable pin. HVEN is battery-voltage tolerant.
Internal High-Side Switch Supply Input. V
provides power to the internal
SUPSW
switch and LDO. Connect a 10μF ceramic capacitor in parallel with a 47μF
electrolytic capacitor from SUPSW to PGND. See the DC-DC Input Capacitor
section.
26, 27
28
26, 27
28
SUPSW
VBMON
USB VBUS monitor.
www.maximintegrated.com
Maxim Integrated | 19
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
Pin Description (continued)
PIN
NAME
FUNCTION
MAX20461
MAX20461A
DC-DC converter feedback input and current-sense amplifier positive input. DC-
DC bulk capacitance placed here. Connect to positive terminal of current-sense
resistor and the main output of the converter. Used for internal voltage regulation
loop.
29
29
SENSP
Current-sense amplifier negative input. Connect to negative terminal of current-
sense resistor.
30
31
30
31
SENSN
Gate drive output. Optionally connect to the gate of an external N-channel FET,
otherwise terminate with 10pF.
G_DMOS
5V linear regulator output. Connect a 2.2µF ceramic capacitor from BIAS to GND.
BIAS powers the internal circuitry.
32
32
BIAS
EP
EP
EP
Exposed pad. Connect EP to multiple GND planes with 3 x 3 via grid (minimum).
Functional Diagrams
On-Channel -3dB Bandwidth and Crosstalk
V
OUT
ON-LOSS = 20log
+3.3V
V
NETWORK ANALYZER
50Ω 50Ω
IN
IN
V
OUT
CROSSTALK = 20log
V
D+ (D-)
IN
V
IN
+14V
SUPSW
+3.3V
ENBUCK
HVD+
D+
ON-LOSS = 20log
1
MEAS
REF
HVD-
D-
V
OUT
HVD+ (HVD-)
ON-LOSS = 20log
2
HVD+
D-
50Ω
50Ω
CROSSTALK = 20log
1
GND
HVD-
D+
CROSSTALK = 20log
2
ON-LOSS IS MEASURED BETWEEN D+ AND HVD+, OR D- AND HVD-.
CROSSTALK IS MEASURED FROM ONE CHANNEL TO THE OTHER CHANNEL.
SIGNAL DIRECTION THROUGH SWITCH IS REVERSED; WORST VALUES ARE RECORDED.
www.maximintegrated.com
Maxim Integrated | 20
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
Functional Diagrams (continued)
On-Capacitance
+3.3V
IN
+14V
D_ OR
HVD_
SUPSW
CAPACITANCE
METER
+3.3V
ENBUCK
GND
DCDC_ON Reset Behavior and Timing Diagram
HVEN
DCDC_ON TOGGLE
DCDC_ON TOGGLE
> 2s
< 2s
DCDC_ON
R
D
ALREADY ATTACHED &
I2C CONFIGURED BIT = 1
ON
USB SIGNAL
CHAIN ACTIVE
OFF
ON
SENSN
DISCHARGE
t
t
DIS_CD
DIS_CD
OFF
ON
BUCK
CONTROL
OFF
t
+
BUCKOFF_CD
t
t
BUCK_WAIT +
t
CCDEBOUNCE
DIS_POR
t
CCDEBOUNCE
t
CCDEBOUNCE
www.maximintegrated.com
Maxim Integrated | 21
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
Functional Diagrams (continued)
ADC Timing Diagram
ADC_REQ
ADC_USBV
ADC_USBI
ADC_TEMP
ADC_DONE
INT
EN_ADC_DONE
SAMPLE READY
IRQ_0 READ
SAMPLE READY
IRQ_0 READ
MASTER WRITES
ADC_REQ
MASTER WRITES
ADC_REQ
AND
EN_ADC_DONE
www.maximintegrated.com
Maxim Integrated | 22
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
Functional Diagrams (continued)
ATTACH Logic Diagram
SOFT START DONE
CC_ATTACH
LDO
SWITCHOVER
CC_ENB
500ms
ASSERTION
DELAY
CC_ENB
0
DCDC ENABLE
ENABLE FPWM
1
1ms
ASSERTION
DELAY
CURRENT SENSE
ATTACH CRITERIA
BC_ATTACH
1
USB2 DATA-LINE
ATTACH CRITERIA
INT (ATTACH)
PIN
INT
0
CD[1]
CD[0]
STANDALONE
Cable Attach-Detach and SENSN Discharge Timing Diagram
PASSENGER PHONE [R ] & PASSENGER POWERED CABLE [R ]
PASSENGER PHONE [R ] & PASSENGER UN-POWERED CABLE
D
D
A
WITH VCONN CONSIDERATIONS
DCDC_ON low for ≥ 2s
DCDC_ON low for ≥ 2s
R
R
D
D
DCDC_ON
DETACH
DETACH
R
R
D
D
V
BIAS
ATTACH
ATTACH
CC1
CC2
CC2 DRIVEN
V
CONN
0
CC2 DRIVEN
pin = 5V
R
A
V
BIAS
ATTACH
V
CONN
CC2 UNUSED
pin = 0V
0
SENSN
G_DMOS
SENSN
DISCHARGE
11ms
DEBOUNCE
11ms
DEBOUNCE
t
t
CCDEBOUNCE
CCDEBOUNCE
t
t
DIS_DET
DIS_DET
R
A
ATTACH Region
www.maximintegrated.com
Maxim Integrated | 23
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
Functional Diagrams (continued)
Detailed Block Diagram
CC2
CC1
V
CONN
VBMON
IN
BC1.2 (CDP, SDP)
HOST CHARGER
EMULATION
USB TYPE-C DFP AND
ORIENTATION
AGND
MAX20461
DETECTION
HVDM
HVDP
DM
DP
G_DMOS
SENSN
SENSP
CHARGE PUMP
SENSN MON
CONFIG1
CURRENT-SENSE AMP
OV
7.46V
SDA (CONFIG2)
SCL (CONFIG3)
BCMODE
SHORT
BIAS
LDO
2.0V
4.37V
0.5V
BIAS
UV
I/O CONTROL
AND
DIAGNOSTICS
FEEDBACK
FAULT
ADJUSTMENT
BST
REMOTE
CABLE
DISCH
INT (ATTACH)
SUPSW
SENSE
ENBUCK
HVEN
HS_CS
USB
OVERCURRENT
THRESHOLD
TEMP
MONITOR
ADC
3.5A FPWM
BUCK
CONVERTER
LX
CC_POL/SHIELD
SYNC
OSC
PGND
LS_CS
www.maximintegrated.com
Maxim Integrated | 24
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
Functional Diagrams (continued)
CC2
CC1
VBMON
USB TYPE-C DFP AND
ORIENTATION
IN
DETECTION
BC1.2 (CDP, SDP)
HOST CHARGER
EMULATION
AGND
MAX20461A
HVDM
HVDP
DM
DP
G_DMOS
SENSN
SENSP
CHARGE PUMP
SENSN MON
CONFIG1
CURRENT-SENSE AMP
OV
7.46V
2.0V
SDA (CONFIG2)
SCL (CONFIG3)
BCMODE
SHORT
UV
BIAS
LDO
BIAS
I/O CONTROL
AND
DIAGNOSTICS
FEEDBACK
ADJUSTMENT
4.37V
0.5V
FAULT
BST
REMOTE
CABLE
DISCH
INT (ATTACH)
SUPSW
SENSE
ENBUCK
HVEN
HS_CS
USB
OVERCURRENT
THRESHOLD
TEMP
MONITOR
ADC
3.5A FPWM
BUCK
CONVERTER
LX
CC_POL/SHIELD
SYNC
OSC
PGND
LS_CS
www.maximintegrated.com
Maxim Integrated | 25
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
Detailed Description
The MAX20461 combines a 5V/3A automotive-grade step-down converter, a USB host charger emulator, and USB
2
protection switches. The device variants offer options for both stand-alone/GPIO and I C configuration and control. This
device family is designed for high-power USB ports in automotive radio, navigation, connectivity, USB hub, and dedicated
charging applications.
The MAX20461 features high-voltage, high-ESD, 1GHz bandwidth data switches. MAX20461 protects up to 18V and
includes internal ESD protection circuitry.
The data switches of all device variants protect the sensitive 3.3V pins of the USB transceiver and support USB Low-
Speed (1.5Mbps), Full-Speed (12Mbps) and Hi-Speed (480Mbps) communication modes. The internal host charger
port-detection circuitry offers automatic sensing and conformance to multiple standards, including USB Type-C 3.0A/
1.5A/0.5A and USB-IF BC1.2 CDP/SDP modes. All variants enable USB-IF OTG, Apple CarPlay, and Android Auto
conformance, while retaining industry-leading protection features and automotive-grade robustness.
The high-efficiency step-down DC-DC converter operates with an input voltage up to 28V, and is protected from load
dump transients up to 40V. The DC-DC converter can be programmed from 310kHz to 2.2MHz switching frequency, or
synced to 248kHz to 2.2MHz switching frequency. The converter can deliver 3A of continuous current at 105°C.
The MAX20461 features a high-side current-sense amplifier and a programmable feedback-adjustment circuit that
provides automatic USB voltage adjustment to compensate for voltage drops in captive cables associated with
automotive applications. The precision current sense allows for an accurate DC output current limit that minimizes the
solution component size and cost.
USB Type-C
USB Type-C introduces a new connector, cable, and detection mechanism while maintaining backwards compatibility
with the existing USB ecosystem. The small-form-factor Type-C connector is reversible and bidirectional, which
eliminates the Type A/Type B distinction. To maintain the USB host/device relationship, Type-C requires a configuration
channel (CC). The CC pins are used to advertise and detect current capabilities and for the host to detect the cable
orientation, which is required for USB3 and active cables.
A Type-C implementation supports, but does not require, USB Power Delivery, BC1.2, and USB3. For backwards
compatibility, a USB3 implementation also requires an independent USB 2.0 channel. It is also advisable to implement
BC1.2 detection, in addition to CC detection, on HVDP/HVDM. This ensures the highest possible charge current when a
legacy adapter is used. Table 1 shows the precedence of power negotiation as mandated by USB-IF. See USB Type-C
2.0 for details.
The MAX20461 provides an integrated Type-C 5V solution tailored to the automotive market. The device integrates all
control and power circuitry necessary to maintain a 5V/3A downstream facing port (DFP) at the end of a captive-cable.
It also provides BC1.2 charge detection, USB 2.0 data protection, and support for USB3 cable orientation detection and
V
CONN
power.
Table 1. Charge Detection Precedence
PRECEDENCE
MODE OF OPERATION
USB Type-C @ 3A Advertisement
USB Type-C @ 1.5A Advertisement
USB BC1.2
NOMINAL VOLTAGE
MAXIMUM CURRENT
5V
5V
5V
5V
5V
3A
Highest
↓
1.5A
≤ 1.5A
900 mA
500 mA
Lowest
USB 3.1
USB 2.0
Default USB Power
Configuration Channel (CC1 and CC2)
The CC pins utilize combinations of pullups and pulldowns to detect Type-C device attachment, advertise the current
capabilities of the source, and detect the type and orientation of the cable and the device. There are three possible pullup
www.maximintegrated.com
Maxim Integrated | 26
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
resistors (R ) that represent the three source current capabilities: 0.5A, 1.5A, and 3A. There are also two possible device
P
pulldown resistors (R and R ) to provide device and cable information to the host. Figure 1 shows how these are used
A
D
for Type-C detection on the CC pins. This configuration allows for simultaneous advertisement and detection. The Type-
C specification also allows for dynamic R changes without any resets. Table 2, Table 3 and Cable Attach-Detach and
P
SENSN Discharge Timing Diagram detail how the MAX20461 responds to the various combinations or R and R .
A
D
Table 2. CC Pulldown Response
MAX20461 ACTION TAKEN
CC1
CC2
TYPE-C STATUS
Nothing attached
Sink attached
VBUS VCONN
CC_ATTACH
CC_POL
CC_PIN_STATE
0b00
Open Open
Open
Off
On
On
Off
Off
On
On
Off
Off
Off
Off
0
1
1
0
0
1
1
0
0
0
1
0
0
0
1
0
0
0
R
D
0b01
Open
Open
R
R
Off
0b10
D
Off
0b00
A
Powered cable without Sink attached
Powered cable with Sink attached
R
A
R
D
R
A
R
D
R
A
Open
Off
0b00
R
A
R
D
R
D
R
A
On CC2
On CC1
Off
0b01
0b10
Debug Accessory attached
0b00
Audio Adapter Accessory attached
Off
0b00
Table 3. CC Pulldown Response (MAX20461A)
MAX20461A ACTION TAKEN
CC1
CC2
TYPE-C STATUS
Nothing attached
Sink attached
VBUS
Off
CC_ATTACH
CC_POL
CC_PIN_STATE
Open
Open
Open
0
1
1
0
0
1
1
0
0
0
1
0
0
0
1
0
0
0
0b00
0b01
0b10
0b00
0b00
0b01
0b10
0b00
0b00
R
D
On
Open
Open
R
R
On
D
Off
A
Powered cable without Sink attached
Powered cable with Sink attached
R
A
R
D
R
A
R
D
R
A
Open
Off
R
A
R
D
R
D
R
A
On
On
Debug Accessory attached
Off
Audio Adapter Accessory attached
Off
www.maximintegrated.com
Maxim Integrated | 27
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
SOURCE MONITORS
FOR CONNECTION
AND ORIENTATION
SINK MONITORS FOR
CURRENT CAPABILITY
BIAS
CC
R
R
D
D
R
R
P
R
A
R
A
P
SOURCE MONITORS
FOR CONNECTION
AND ORIENTATION
SINK MONITORS FOR
CURRENT CAPABILITY
Figure 1. Type-C Pullup Model
CC Polarity Output Pin (CC_POL)
The MAX20461 features an open-drain, active-low CC polarity output. The pin will assert low when R is detected on
D
CC2. See Table 2.
V
CONN
(MAX20461 Only)
While there are two CC pins that must be monitored on the host receptacle, there is only one CC wire running through
the Type-C cable. This allows orientation to be determined, and leaves the second CC pin available for other uses. The
Type-C specification allows the unused CC pin to operate as V
, which is a low power source intended to power
CONN
active cables that can include authentication ICs or superspeed muxes.
The MAX20461 includes complete support for V power control and protection. When a power source within
CONN
the acceptable operating voltage is connected to the V
pin, MAX20461 can connect the voltage source to the
CONN
appropriate CC pin. Back-to-back V
FETs provide overvoltage and overcurrent protection to the V
source in
CONN
CONN
addition to controlling the application of V
per the Type-C specification.
CONN
Table 4. Type-C Source V
Requirements
CONN
PORT FEATURES
V
CONN
REQUIREMENTS
D+/D-
No
SSTX/SSRX, VPD
>3A
No
No
No
Not required
Not required
1W, 3V-5.5V
Yes
Yes
No
Yes
No
www.maximintegrated.com
Maxim Integrated | 28
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
BIAS
CC2_VCONN_EN
CC1_VCONN_EN
R
P
R
P
CC1_RP_EN
CC2_RP_EN
CC1
CC2
V
CONN
V
ILIM
CONN
5.5V CLAMPS
CC1_VRA_RD
CC1_VOPEN
CC2_VRA_RD
CC2_VOPEN
VCONN_UVLO
Type C
Control Logic
CC1_VCONN_EN
CC2_VCONN_EN
CC1_RP_EN
VRA_RD
VOPEN
CC2_RP_EN
VSAFE0V
VBMON
R
P
CC_CUR_SRC[1:0]
V
V
RA_RD
OPEN
ENBUCK
DCDC_ON
G_DMOS
EN_DCDC
R
P
Enable
BUCK CONTROL
CC_ENB
FAULT RETRY TIMER EXPIRED
STARTUP/DISCHARGE TIMER EXPIRED
DCDC_ON RETRY TIMER EXPIRED
ALLOW DCDC
Figure 2. USB Type-C Block Diagram
V
BUS
Type-C includes new requirements for V
, even when operating exclusively in 5V mode. When no device is attached
BUS
to the CC pins, the host must switch the V
source off so that near zero volts is present at the receptacle pin. To
BUS
achieve this, the MAX20461 disables the external FET gate drive and turns off the buck converter when in a detached
state, reducing quiescent current. The MAX20461 integrates control and discharge circuits to ensure all Type-C timing
requirements are met. Throughout this document, the term V
is used loosely to refer to voltage at SENSP, SENSN
BUS
or VBMON. When more precision is required, the specific pin name is referenced.
www.maximintegrated.com
Maxim Integrated | 29
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
External FET Gate Drive (G_DMOS Pin)
The MAX20461 includes a gate drive for an optional external FET that can be used to isolate the bulk capacitance when
is not being sourced. If used, connect the G_DMOS pin to the gate of the external FET. If not used, terminate
V
BUS
G_DMOS with a 10pF capacitor. G_DMOS activates prior to soft-start, and turns off after discharge. If V
battery is required, the FET should be appropriately rated. The external DMOS device must be a 20V V
charge pump generates at least 7V.
short-to-
type. The
BUS
GS
Legacy Devices
The Type-C specification ensures interoperability with Type-A and Type-B devices by defining requirements for legacy
adapters. As a DFP, relevant adapters connect from the Type-C receptacle to either a Type-B plug or to a Type-A
receptacle, which can then be used with any legacy Type-A cable. A compliant legacy adapter of this type must include
an R termination inside the adapter. In this case, the MAX20461 detects a Type-C attachment whenever the adapter
D
is connected, regardless of whether a portable device is connected. The portable device sees the DFP as a BC1.2 port
(when configured as such).
Power-Up and Enabling
System Enable (HVEN)
HVEN is used as the main enable to the device and initiates system start-up and configuration. If HVEN is at a logic-low
level, SUPSW power consumption is reduced and the device enters a standby, low quiescent current level. HVEN is
compatible with inputs from 3.3V logic up to automotive battery. After a system reset (e.g., HVEN toggle, BIAS UV), the
2
I C variant asserts the INT pin to indicate that the IC has not been configured. The buck converter is forced off until the
CONFIGURED bit of SETUP_4 is written to a 1. This ensures that a portable device cannot attach before the IC registers
are correctly set for the application.
DC-DC Enable (ENBUCK)
The buck regulator on the MAX20461 is controlled by the ENBUCK pin for stand-alone variants, and by both the ENBUCK
2
2
pin and the I C interface for I C variants. DCDC_ON, the logical AND of ENBUCK and EN_DCDC, determines if the
buck converter can be enabled by the Type-C control logic. On stand-alone variants, EN_DCDC is always high and only
2
2
ENBUCK can be used to enable the buck converter. On I C variants, setting ENBUCK low overrides an I C EN_DCDC
enable command, which allows compatibility with USB hub controllers. For a typical USB hub application, connect
ENBUCK to the enable output of the USB hub controller. This allows the USB hub controller to enable and disable the
USB power port using software commands. ENBUCK can be directly connected to the BIAS or IN pin for applications
that do not require GPIO control of the DC-DC converter enable.
3.3V Input (IN)
IN is used to clamp the D+ and D- pins during an ESD or overvoltage event on the HVD+ and HVD- pins. This clamping
protects the downstream USB transceiver. The presence of these clamping diodes requires that IN remain set to 3.3V at
all times for USB communication to occur. The IN pin features an overvoltage lockout that disables the data switches if
IN is above V
. Bypass IN with a 1μF ceramic capacitor, place it close to the IN pin, and connect it to the same
IN_OVLO
3.3V supply that is shared with the multimedia processor or hub transceiver.
Linear Regulator Output (BIAS)
BIAS is the output of a 5V linear regulator that powers the internal logic and control circuitry for the device. BIAS is
internally powered from SUPSW or SENSP and automatically powers up when HVEN is high and SUPSW voltage
exceeds V
. The BIAS output contains an undervoltage lockout that keeps the internal circuitry disabled when
UV_SUPSW
BIAS is below V
. The linear regulator automatically powers down when HVEN is low, and a low shutdown current
UV_BIAS
mode is entered. Bypass BIAS to GND with a 2.2μF ceramic capacitor.
Power-On Sequencing
HVEN, ENBUCK and IN do not have a power-up sequence requirement by design. However, the desired system
behavior should be considered for the state of these pins at startup. The D+ and D- pins are clamped to IN, therefore IN
www.maximintegrated.com
Maxim Integrated | 30
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
should be set to 3.3V before any USB communication is required. It is recommended that IN is set to 3.3V before HVEN
is set high. ENBUCK acts as the master disable for the DC-DC converter. If ENBUCK is low when HVEN is set high, all
variants keep the buck converter in the disabled state until ENBUCK is set high.
Step-Down DC-DC Regulator
Step-Down Regulator
The MAX20461 features a current-mode, step-down converter with integrated high-side and low-side MOSFETs. The
low-side MOSFET enables fixed-frequency, forced-PWM operation under light loads. The DC-DC regulator features a
cycle-by-cycle current limit and intelligent transition from skip mode to forced-PWM mode that makes the device ideal for
automotive applications.
Wide Input Voltage Range
The device is specified for a wide 4.5V to 28V input voltage range. SUPSW provides power to the internal BIAS linear
regulator and internal power switch. Certain conditions such as cold cranking can cause the voltage at the output to drop
below the programmed output voltage. Under such conditions, the device operates in a high duty-cycle mode to facilitate
minimum dropout from input to output.
Maximum Duty-Cycle Operation
The MAX20461 has a maximum duty cycle of 98% (typ). The IC monitors the off-time (time for which the low-side FET
is on) in both PWM and skip modes for every switching cycle. Once the off-time of 150ns (typ) is detected continuously
for 7.5μs, the low-side FET is forced on for 60ns (typ) every 7.5μs. The input voltage at which the device enters dropout
changes depending on the input voltage, output voltage, switching frequency, load current, and design efficiency. The
input voltage at which the devices enter dropout can be approximated as:
V
+ I
× R
ONH
(
)
OUT
LOAD
V
=
SUPSW
0.98
Note: The equation above does not take into account the efficiency and switching frequency but will provide a good first-
order approximation. Use the R
(max) in the Electrical Characteristics table.
ONH
Output Voltage (SENSP)
The device features a precision internal feedback network that is connected to SENSP and that is used to set the output
voltage of the DC-DC converter. The network nominally sets the average DC-DC converter output voltage to the voltage
that corresponds to the V
configuration register, with a default value of 5.15V.
OUT
Soft-Start
When the DC-DC converter is enabled, the regulator soft-starts by gradually ramping up the output voltage from 0V to
5.15V over approximately 8ms. This soft-start feature reduces inrush current during startup. Soft-start is guaranteed into
compliant USB loads (see the USB Loads section).
Reset Behavior
The MAX20461 implements a discharge function on SENSN any time that the DC-DC regulator is disabled for any
reason. When the discharge function is activated, current (I
) is drained through a current-limited FET, and a
SENSN_DIS
reset timer is also started. This timer prevents the DC-DC regulator from starting up again until the timer has expired.
This allows for easy compatibility with USB specifications and removes the need for long discharge algorithms to be
implemented in system software. See the relevant Functional Diagrams and Figure 2 for reset timer details.
Reset Criteria
The MAX20461 DC-DC converter automatically resets for all undervoltage, overvoltage, overcurrent and
overtemperature fault conditions. See Table 12 for details. The fault retry timer is configurable in the SETUP_3 register.
This timer is activated after a fault condition is removed and prevents the buck converter from switching on until the timer
expires.
www.maximintegrated.com
Maxim Integrated | 31
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
Another internal retry timer is enabled after DCDC_ON is set low or a Type-C detach event. DCDC_ON toggle causes
buck shutdown and prevent the buck from switching on until t
buck shutdown and prevent the buck from switching on until t
expires. A Type-C detach event will cause
expires.
BUCKOFF_CD
BUCKOFF_DET
Switching Frequency Configuration
The DC-DC switching frequency can be referenced to an internal oscillator or from an external clock signal on the SYNC
pin. The internal oscillator frequency is set by the FSW[2:0] bits of the SETUP_1 register, which has a POR value
2
corresponding to 2.2MHz. The internal oscillator can be programmed via I C to eight discrete values from 310kHz to
2.2MHz. For standalone variants, FSW configuration value is loaded from the CONFIG1 pin at startup with four discrete
values from 310kHz to 2.2MHz available.
Switching Frequency Synchronization (SYNC Pin)
When the SYNC pin is configured to operate as an output, skip mode operation is disallowed, and the internal oscillator
drives the SYNC pin. This allows other devices to synchronize with the MAX20461 180 degrees out of phase for EMI
reduction.
When SYNC is configured as an input, the SYNC pin becomes a logic-level input that can be used for both operating-
mode selection and frequency control. Connecting SYNC to GND or an external clock enables fixed-frequency, forced-
PWM mode. Connecting SYNC to a logic-high signal allows intelligent skip-mode operation (Type-A mode, i.e. CC_ENB
= 1) or FPWM mode (default Type-C mode, i.e. CC_ENB = 0). The device can be externally synchronized to frequencies
within ±20% of the programmed internal oscillator frequency.
Forced-PWM Operation
In forced-PWM mode, the device maintains fixed-frequency PWM operation over all load conditions, including no-load
conditions.
Intelligent Skip-Mode Operation and Attach Detection
2
When the SYNC pin is configured as an input and CC_ENB = 1 (via I C only), but neither a clocked signal nor a logic-
low level exists on the SYNC pin, the MAX20461 operates in skip mode at very light load/no load conditions. Intelligent
device attach detection is used to determine when a device is attached to the USB port. The device intelligently exits
skip mode and enters forced-PWM mode when a device is attached and remains in forced-PWM mode as long as the
attach signal persists. This minimizes the EMI concerns caused by automotive captive USB cables and poorly shielded
consumer USB cables. The device attach event is also signaled by the ATTACH pin (stand-alone variants) or ATTACH
2
bits (I C variants). The criteria for device attach detection and intelligent skip-mode operation are shown in Table 5. Note
that when operating in Type-C mode, the buck only switches on when a Type-C device is attached. This means skip
mode cannot be entered if CC_ENB = 0.
Table 5. DC-DC Converter Intelligent Skip Mode Truth Table
SYNC
PIN
SYNC_ DATA SWITCH CHARGE CDP ATTACH
CURRENT SENSE
ATTACH DETECTION
DC-DC CONVERTER
OPERATION
CC_ENB
DIR BIT
DETECTION MODE
DETECTION
Forced-PWM Mode:
Type-C Device Attached
0
1
1
1
1
1
x
x
x
x
x
x
x
x
0
1
Forced-PWM Mode:
Continuous
x
1
0
0
0
0
x
x
x
x
x
x
x
x
Forced-PWM Mode:
Continuous
0
Forced-PWM Mode:
Continuous
Clocked
High-Speed Pass Thru
(SDP) Mode
Intelligent Skip Mode: No
Device Attached
1
1
High-Speed Pass Thru
(SDP) Mode
Forced-PWM Mode:
Device Attached
www.maximintegrated.com
Maxim Integrated | 32
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
Table 5. DC-DC Converter Intelligent Skip Mode Truth Table (continued)
SYNC
PIN
SYNC_ DATA SWITCH CHARGE CDP ATTACH
CURRENT SENSE
ATTACH DETECTION
DC-DC CONVERTER
OPERATION
CC_ENB
DIR BIT
DETECTION MODE
DETECTION
Intelligent Skip Mode: No
Device Attached
1
1
1
1
1
1
0
BC1.2 Auto CDP Mode
0
0
x
1
Forced-PWM Mode:
Device Attached
0
0
BC1.2 Auto CDP Mode
BC1.2 Auto CDP Mode
1
x
Forced-PWM Mode:
Device Attached
Spread-Spectrum Option
Spread-spectrum operation is offered to improve the EMI performance of the MAX20461. Spread-spectrum operation is
enabled by the SS_EN bit of the SETUP_0 register, which is preloaded on startup from the CONFIG1 pin for both stand-
2
alone and I C variants. The internal operating frequency modulates the switching frequency by up to ±3.4% relative to
the internally generated operating frequency. This results in a total spread-spectrum range of 6.8%. Spread-spectrum
mode is only active when operating from the internal oscillator. Spread-spectrum clock dithering is not possible when
operating from an external clock.
Current Limit
The MAX20461 limits the USB load current using both a fixed internal peak current threshold of the DC-DC converter,
as well as a user-programmable external DC load current-sense amplifier threshold. This allows the current limit to be
adjusted between 300mA to 3A depending on the application requirements, while protecting the system in the event of a
fault. Upon exceeding either the DC-DC peak or user-programmable current thresholds, the high-side FET is immediately
switched off and current-limit algorithms are initiated. When the external current limit lasts for longer than 16ms, the
FAULT pin asserts and the VBUS_ILIM bit of the IRQ_1 register is set. Once the load current exceeds the programmed
threshold, the DC-DC converter acts as a constant-current source. This may cause the output voltage to droop. The
ILIM_ITRIP bit of the SETUP_2 register determines the output voltage droop required to initiate a DC-DC converter reset
during VBUS_ILIM. When ILIM_ITRIP = 0, the USB current limit is detected for 16ms and the output voltage falls below
V
, the DC-DC converter resets. The DC-DC converter also resets if the internal LX peak current threshold is
UV_SENSN
exceeded for four consecutive switching cycles and the output voltage droops to less than 2.0V.
In some cases, the designer may want to increase the load to 160%, refer to USB Output Current Limit for details.
Output Short-Circuit Protection
The DC-DC converter output (SENSP, SENSN) is protected against both short-to-ground and short-to-battery conditions.
If a short-to-ground or undervoltage condition is encountered, the DC-DC converter immediately resets, asserts the
FAULT pin, flags the fault in the IRQ_1 register, and then reattempts soft-start after the reset delay. This pattern repeats
until the short circuit has been removed.
If a short-to-battery is encountered (V
> V
), the buck converter shuts down, G_DMOS is disabled, the
OV_SENSN
SENSN
FAULT pin is asserted, and the fault is flagged in the IRQ_1 register. The buck converter stays shut down until the fault
condition resolves and the 2s timer expires.
Thermal Overload Protection
Thermal overload protection limits the total power dissipated by the device. A thermal-protection circuit monitors the die
temperature. If the die temperature exceeds +165°C, the device shuts down, so it can cool. Once the device has cooled
by 10°C, the device is enabled again. This results in a pulsed output during continuous thermal overload conditions,
protecting the device during fault conditions. For continuous operation, do not exceed the absolute maximum junction
temperature of +150°C. See the Thermal Considerations section for more information.
Pre-Thermal Overload Warning
2
The MAX20461 I C variant features a thermal overload warning flag which sets the THM_WARN bit of the IRQ_2 register
www.maximintegrated.com
Maxim Integrated | 33
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
when the die temperature crosses +140°C. This allows a system software implementation of thermal foldback or load
shedding algorithms to prevent a thermal overload condition.
Automatic Thermal Foldback
All MAX20461 variants implement a thermal foldback feature which, when enabled, reduces the Type-C current
advertised on the CC pins by R . When THM_WARN = 1, the R current advertisement reduces to the setting
P
P
immediately below what is set in CC_CUR_SRC[1:0]. When the die temperature drops below the thermal warning
threshold, R returns to its original setting based on CC_SRC_CUR[1:0].
P
Note that Type-C allows for dynamic R changes in the Attached.SRC state without reinitializing detection. The
P
MAX20461 thermal foldback does not: force BUS to reset, change the BC1.2 mode, or reduce the USB current
limit. Alternative thermal foldback algorithms are available and can be performed in system software. Contact Maxim
Applications for support.
USB Current Limit and Output Voltage Adjustment
Current-Sense Amplifier (SENSP, SENSN)
MAX20461 features an internal USB load current-sense amplifier to monitor the DC load current delivered to the USB
port. The V
voltage (V
- V
) is used internally to provide precision DC current-limit and voltage-
SENSE
SENSP
SENSN
compensation functionality. A 33mΩ sense resistor should be placed between SENSP and SENSN.
In some cases, the designer may want to increase the load to 160%, refer to USB Output Current Limit for details.
USB DC Current Limit Configuration
2
The MAX20461 allows configuration of the precision DC current limit by the ILIM[2:0] bits of the SETUP_2 register. I C
configuration enables selection of eight discrete DC current limit values. See SETUP_2 for current limit configuration
values.
Stand-alone variants of the device allow selection of a subset of the eight available current limit options by reading the
CONFIG3 resistor. See Table 10 and the Applications Information section for more information.
In some cases, the designer may want to increase the load to 160%, refer to USB Output Current Limit for details.
Voltage Feedback Adjustment Configuration
2
The MAX20461 compensates voltage drop for up to 474mΩ of USB cable in typical USB charging applications. I C
variants of the device allow this configuration by the GAIN[4:0] bits of the SETUP_1 register. See GAIN[4:0] for voltage
gain configuration. Stand-alone variants of the device allow configuration by the CONFIG2 resistor, which sets GAIN[3:0],
and the CONFIG3 resistor, which sets GAIN[4]. See the SETUP_1 register map and the Applications Information section
for more information.
In some cases, the designer may want to increase the load to 160%, refer to USB Output Current Limit for details.
Remote Sense Feedback Adjustment
The remote-sense feature (available by custom order only) provides another option to adjust the output voltage by
sensing the ground node on the USB port at the far-end of the captive cable; either with the cable shield or with an
additional sensing wire. This feature automatically senses the cable resistance and adjusts the voltage compensation
without changing the GAIN[4:0] setting.
The user needs to compensate the voltage drop because of the sense resistor, the load line behavior of the buck, and
any difference between the V
order.
and GND conductors. See Figure 3 and contact the factory for support and how to
BUS
www.maximintegrated.com
Maxim Integrated | 34
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
REGULATED FOR
+ VDUT
-
I
LOAD and RCABLE
CAPTIVE
USB CABLE
MAX20461
R
VBUS
HVBUS
HVD-
DM
DP
PORTABLE
DEVICE
HVD+
AGND
SHEILD
R
GND
USB SHEILD OR
SENSE WIRE
GAIN[4:0] =
CANNOT CONNECT TO IC GND
Figure 3. Remote Cable-Sense Diagram
High Voltage Modes Configuration
2
I C variants of the MAX20461 allow high output voltage mode configurations for flexible use in higher power charging
applications, and for load-dump protected battery pass-through output to automotive modules. Contact factory for
support.
USB Protection Switches and BC1.2 Host Charger Emulation
USB Protection Switches
MAX20461 provides automotive-grade ESD and short-circuit protection for the low-voltage USB data lines of high-
integration multimedia processors. HVDP/HVDM protection consists of ESD and OVP (overvoltage protection) for
1.5Mbps, 12Mbps, and 480Mbps USB transceiver applications. This is accomplished with a very low-capacitance FET in
series with the D+ and D- data path.
The MAX20461 does not require an external ESD array, and protects the HVD+ and HVD- pins to ±15kV Air-Gap/±8kV
Contact Discharge with the 150pF/330Ω IEC 61000-4-2 model and the 330pF/330Ω model, as well as protecting up
to ±25kV Air-Gap/±8kV Contact Discharge with the 330pF/2kΩ ISO 10605 model. The MAX20461 provides robust,
automotive-grade protection while maintaining a 1GHz -3dB insertion loss. This ensures optimum eye diagram at the end
of a captive cable.
The HVD+ and HVD- short-circuit protection features include protection for a short to the USB +5V BUS and a short to
the +18V car battery. These protection features prevent damage to the low-voltage USB transceiver when shorts occur
in the vehicle harness or customer USB connector/cable. Short-to-GND protection is provided by the upstream USB
transceiver.
USB Host Charger Emulator
The USB protection switches integrate the latest USB-IF Battery Charging Specification Revision 1.2 CDP and SDP
circuitry.
2
Table 6. Data Switch Mode Truth Table (I C Variant, ATJA)
DEVICE INPUTS
SA
SB
DATA SWITCH MODE
HVEN
IN
X
CD[1]
CD[0]
BCMODE
0
1
X
X
X
X
X
1
0
0
Off
0
Invalid Mode (IN = 3.3V required for all modes)
www.maximintegrated.com
Maxim Integrated | 35
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
2
Table 6. Data Switch Mode Truth Table (I C Variant, ATJA) (continued)
1
0
0
X
0
Invalid Mode (IN = 3.3V required for all modes)
1
1
0
0
0
1
0
Hi-Speed Pass-Through (SDP)
BC1.2 Auto-CDP (CDP)
On if
CDP = 0
On if
CDP = 1
1
1
1
1
0
1
0
1
On if
CDP = 0
On if
CDP = 1
X
X
BC1.2 Auto-CDP (CDP)
Table 7. Data Switch Mode Truth Table (Standalone Variant, ATJD)
DEVICE INPUTS
SA
SB
DATA SWITCH MODE
HVEN
IN
X
0
BCMODE
0
1
1
X
X
0
0
0
Off
Invalid Mode (IN = 3.3V required for all modes)
1
1
0
Hi-Speed Pass-Through (SDP)
BC1.2 Auto-CDP (CDP)
On if
CDP = 1
1
1
1
On if CDP = 0
www.maximintegrated.com
Maxim Integrated | 36
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
IN
SA
DP
HVDP
ESD
POTECTION
SA
SB
SB
DM
HVDM
ESD
POTECTION
DEVICE
USB 2.0
DISCONNECT
HOST CHARGER
FOR 500ms
R
EMULATION
S
Q
CDP
LS/FS DETECTION
ON HVDP/HVDM
CD[1:0]
BCMODE
HVEN
ATTACH
FAULT/ERROR
CONTROL
LOGIC
SA
SB
HVDP/HVDM OV
IN OV
CDP
MAX20461
Figure 4. Data Switch and Charge-Detection Block Diagram
USB On-The-Go and Dual-Role Applications
The MAX20461 is fully compatible with USB on-the-go (OTG) and dual-role applications. A negotiated role swap (HNP
or Apple CarPlay) requires no software interaction with the IC. When there is no negotiation before the SOC enters
peripheral mode, the MAX20461 must be in Hi-Speed pass-through (SDP mode) before and during the role swap. The
MAX20461ATJA/V+ and MAX20461ATJD/V+ default to SDP mode on startup if the BCMODE pin is logic-low. This
configuration allows a role swap immediately on startup without microcontroller interaction.
2
I C, Control, and Diagnostics
2
2
I C Configuration (CONFIG1 and I C)
2
The MAX20461 I C variants allow basic device configuration through a resistor placed to GND on the CONFIG1 pin. The
2
configuration parameters correlating to the chosen resistor are pre-loaded into their respective I C registers on startup
2
when HVEN is toggled high. After startup, the user is free to change the affected I C registers as desired.
www.maximintegrated.com
Maxim Integrated | 37
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
2
For I C variants, CONFIG1 sets the startup value of the DC-DC spread-spectrum enable bit SS_EN and the SYNC
2
direction control bit SYNC_DIR. CONFIG1 also sets the LSBs of the I C slave address. The configuration table for the
2
I C variant CONFIG table is shown in Table 8.
2
Table 8. CONFIG1 Pin Table (I C Version)
2
RESISTANCE (Ω, typ)
STEP
SS_EN
1 (ON)
1 (ON)
1 (ON)
1 (ON)
1 (ON)
1 (ON)
1 (ON)
1 (ON)
0 (OFF)
0 (OFF)
0 (OFF)
0 (OFF)
0 (OFF)
0 (OFF)
0 (OFF)
SYNC_DIR
1 (IN)
I C_ADDR LSBs
Short to GND
619
0
00
01
10
11
00
01
10
11
00
01
10
11
00
01
10
1
1 (IN)
976
2
1 (IN)
1370
3
1 (IN)
1820
4
0 (OUT)
0 (OUT)
0 (OUT)
0 (OUT)
1 (IN)
2370
5
3090
6
3920
7
4990
8
6340
9
1 (IN)
8250
10
11
12
13
14
1 (IN)
11000
15400
23700
44200
1 (IN)
0 (OUT)
0 (OUT)
0 (OUT)
Short to BIAS
(or R > 71.5kΩ)
15
0 (OFF)
0 (OUT)
11
Stand-Alone Configuration (CONFIG1–CONFIG3)
The MAX20461 standalone variants allow full device configuration from three resistors placed among the three CONFIG
pins and GND. For standalone variants, SDA and SCL serve as CONFIG2 and CONFIG3, respectively.
CONFIG1 sets the internal oscillator switching frequency, SYNC pin direction, and DC-DC spread spectrum mode.
CONFIG2 sets the 4 LSBs of the voltage adjustment gain (GAIN[3:0]). CONFIG3 sets the USB DC current limit, type-
C current advertisement, automatic thermal foldback, and MSB of voltage adjustment gain (GAIN[4]). See tables below
for stand-alone variant CONFIG options. See the Applications Information section for setting selection and Ordering
Information for variant part number information.
In some cases, the designer may want to increase the load to 160%, refer to USB Output Current Limit for details.
Table 9. CONFIG1 Pin Table (Standalone Variants)
RESISTANCE (Ω, typ)
STEP
SS_EN
SYNC_DIR
IN
FSW (kHz)
2200
488
Short to GND
619
0
1
2
3
4
5
6
7
8
ON
ON
IN
976
ON
IN
350
1370
ON
IN
310
1820
ON
OUT
OUT
OUT
OUT
IN
2200
488
2370
ON
3090
ON
350
3920
ON
310
4990
OFF
2200
www.maximintegrated.com
Maxim Integrated | 38
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
Table 9. CONFIG1 Pin Table (Standalone Variants) (continued)
RESISTANCE (Ω, typ)
STEP
SS_EN
OFF
OFF
OFF
OFF
OFF
OFF
SYNC_DIR
FSW (kHz)
488
6340
8250
9
IN
10
IN
350
11000
15400
23700
44200
11
IN
310
12
OUT
OUT
OUT
2200
488
13
14
350
Short to BIAS
(or R > 71.5kΩ)
15
OFF
OUT
310
Table 10. CONFIG2 and CONFIG3 Pin Table (Standalone Variants)
CONFIG2
CONFIG3
CURRENT LIMIT
ILIM_SET (A)
TYPE-C MODE
CC_SRC_CUR (A)
RESISTANCE (Ω, typ)
STEP
GAIN[3:0]
THM_FLDBK_EN
GAIN[4]
Short to GND
619
0
1
0b0000
0b0001
0b0010
0b0011
0b0100
0b0101
0b0110
0b0111
0b1000
0b1001
0b1010
0b1011
0b1100
0b1101
0b1110
ON
ON
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
0.55
1.62
2.60
3.04
0.55
1.62
2.60
3.04
0.55
1.62
2.60
3.04
0.55
1.62
2.60
0.5
1.5
1.5
3.0
0.5
1.5
1.5
3.0
0.5
1.5
1.5
3.0
0.5
1.5
1.5
976
2
ON
1370
3
ON
1820
4
ON
2370
5
ON
3090
6
ON
3920
7
ON
4990
8
OFF
OFF
OFF
OFF
OFF
OFF
OFF
6340
9
8250
10
11
12
13
14
11000
15400
23700
44200
Short to BIAS
(or R > 71.5kΩ)
15
0b1111
OFF
1
3.04
3.0
2
I C Diagnostics and Event Handling
2
The I C-based diagnostic functionality is independent of the FAULT pin. Setting the IRQMASK bit for a specific fault
condition does not mask the FAULT pin for the respective fault. IRQMASK register functionality affects only the behavior
2
of the INT pin. This allows the FAULT pin to be tied to over-current fault input of a hub controller or SoC, while the I C
interface is simultaneously used by the system software for advanced diagnostic functionality.
Interrupt and Attach Output (INT(ATTACH))
2
The MAX20461 INT(ATTACH) pin functions as an interrupt (INT) for I C variants. The INT pin asserts an interrupt based
on the configuration of the IRQ_MASK_0, IRQ_MASK_1, and IRQ_MASK_2 registers. Interrupt configuration allows the
INT pin to assert any of the featured fault detection, as well as on device attachment, and USB voltage/current ADC
conversion completion. The INT pin only asserts while a masked IRQ bit is asserted, which means its behavior is also
dependent on the AUTOCLR bit.
Stand-alone variants of the MAX20461 feature an open-drain, active-low, ATTACH output that serves as the attach
www.maximintegrated.com
Maxim Integrated | 39
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
detection pin. For standalone variants, the ATTACH pin can be used for GPIO input to a microprocessor, or to drive an
LED for attach/charge indication.
The INT(ATTACH) assertion logic is shown in ATTACH Logic Diagram.
2
I C Output Voltage and Current Measurement
2
The MAX20461 I C variant allows measurement of the instantaneous SENSN voltage, DC output current, and die
temperature using an integrated ADC. To initiate a measurement, set the ADC_REQ bit of the ADC_REQUEST register.
The ADC_REQ bit is cleared by the IC once the measurement is complete and the ADC samples are available.
Additionally, the ADC_DONE bit of the IRQ_0 register will be set when the sample is available. ADC_DONE can be
masked to assert an interrupt when the sample is ready.
The sampled measurements can be read from the ADC_USBV, ADC_USBI, and ADC_TEMP registers. The new sample
persists in the register until another sample request is initiated by setting the ADC_REQ bit.
All measurements provide 8 bits of resolution. The measured SENSN voltage has a range of 0V to 19.8V. Convert the
sample to a voltage as follows
19.8V
V
=
· ADC_USBV (Volts).
256
SENSN
The measured SENSE voltage has a range from 0 to 116mV. Convert the sample to a current as follows
116mV ADC_USBI
I
=
·
(Amps).
LOAD
256
R
SENSE
The measured die temp has a range from -40ºC to 170ºC and a temperature resolution of 3.5ºC. Convert the sample to
a die temperature by T = 3.5ºC · ADC_TEMP - 270 (ºC).
J
2
I C Interface
2
The MAX20461 features an I C, 2-wire serial interface consisting of a serial-data line (SDA) and a serial clock line (SCL).
SDA and SCL facilitate communication between the MAX20461 and the master at clock rates up to 400kHz. The master,
typically a microcontroller, generates SCL and initiates data transfer on the bus. Figure 5 shows the 2-wire interface
timing diagram.
A master device communicates to the MAX20461 by transmitting the proper address followed by the data word. Each
transmit sequence is framed by a START (S) or REPEATED START (Sr) condition and a STOP (P) condition. Each word
transmitted over the bus is 8 bits long and is always followed by an acknowledge clock pulse. The MAX20461 SDA line
operates as both an input and an open-drain output. A pullup resistor greater than 500Ω is required on the SDA bus.
The MAX20461 SCL line operates as an input only. A pullup resistor greater than 500Ω is required on SCL if there are
multiple masters on the bus, or if the master in a single-master system has an open-drain SCL output. Series resistors in
line with SDA and SCL are optional. The SCL and SDA inputs suppress noise spikes to assure proper device operation
even on a noisy bus.
www.maximintegrated.com
Maxim Integrated | 40
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
SDA
SCL
t
BUF
t
t
SU,STA
SU, DAT
t
SP
t
HD,DAT
t
SU,STO
t
LOW
t
HD,DAT
t
HIGH
t
HD,STA
t
t
F
R
START CONDITION
REPEATED START
CONDITION
STOP
CONDITION
START
CONDITION
2
Figure 5. I C Timing Diagram
Bit Transfer
One data bit is transferred during each SCL cycle. The data on SDA must remain stable during the high period of the
SCL pulse. Changes in SDA while SCL is high are considered control signals (see the STOP and START Conditions
2
section). SDA and SCL idle high when the I C bus is not busy.
STOP and START Conditions
A master device initiates communication by issuing a START condition. A START condition is a high-to-low transition
on SDA with SCL high. A STOP condition is a low-to-high transition on SDA while SCL is high (Figure 6). A START (S)
condition from the master signals the beginning of a transmission to the MAX20461. The master terminates transmission,
and frees the bus, by issuing a STOP (P) condition. The bus remains active if a REPEATED START (Sr) condition is
generated instead of a STOP condition.
S
Sr
P
SDA
SCL
t
t
SU:STO
SU:STA
t
t
HD:STA
HD:STA
Figure 6. START, STOP and REPEATED START Conditions
Early STOP Condition
The MAX20461 recognizes a STOP condition at any point during data transmission, unless the STOP condition occurs
in the same high pulse as a START condition.
Clock Stretching
2
2
In general the clock signal generation for the I C bus is the responsibility of the master device. The I C specification
allows slow slave devices to alter the clock signal by holding down the clock line. The process in which a slave device
holds down the clock line is typically called clock stretching. The MAX20461 does not use any form of clock stretching to
hold down the clock line.
2
I C General Call Address
2
The MAX20461 does not implement the I C specifications general call address. If the MAX20461 sees the general call
www.maximintegrated.com
Maxim Integrated | 41
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
address (0b0000_0000), it does not issue an acknowledge.
2
I C Slave Addressing
2
Once the device is enabled, the I C slave address is set by the CONFIG1 pin.
The address is defined as the 7 most significant bits (MSBs) followed by the R/W bit. Set the R/W bit to 1 to configure
the device to read mode. Set the R/W bit to 0 to configure the device to write mode. The address is the first byte of
information sent to the device after the START condition.
2
Table 11. I C Slave Addresses
CONFIG1 CODE
A6
A5
A4
A3
0
A2
0
A1
0
A0
0
7-BIT ADDRESS
WRITE
0x60
0x62
0x64
0x66
READ
0x61
0x63
0x65
0x67
0b00
0b01
0b10
0b11
0
1
1
0x30
0x31
0x32
0x33
0
1
1
0
0
0
1
0
1
1
0
0
1
0
0
1
1
0
0
1
1
Acknowledge
The acknowledge bit (ACK) is a clocked 9th bit that the device uses to handshake receipt each byte of data (Figure
7). The device pulls down SDA during the master generated 9th clock pulse. The SDA line must remain stable and
low during the high period of the acknowledge clock pulse. Monitoring ACK allows for detection of unsuccessful data
transfers. An unsuccessful data transfer occurs if a receiving device is busy or if a system fault has occurred. In the event
of an unsuccessful data transfer, the bus master can reattempt communication.
Not Acknowledge (nA)
S
Acknowledge (A)
SDA
SCL
t
SU:DAT
8
t
HD:DAT
1
2
9
Figure 7. Acknowledge Condition
Write Data Format
A write to the device includes transmission of a START condition, the slave address with the write bit set to 0, one byte
of data to a register address, one byte of data to the command register, and a STOP condition. Figure 8 illustrates the
proper format for one frame.
Read Data Format
A read from the device includes transmission of a START condition, the slave address with the write bit set to 0, one
byte of data from a register address, restart condition, the slave address with read bit set to 1, one byte of data to the
command register, and a STOP condition. Figure 8 illustrates the proper format for one frame.
www.maximintegrated.com
Maxim Integrated | 42
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
Write Byte
Slave
S
Register
Address
0 A
A
Data Byte
A P
Address
Write Sequential Bytes
Slave
Address
Register
Address
S
0 A
A
Data Byte1
A
. . .
Data Byte N A P
Read Byte
Slave
S
Register
Address
Slave
Address
N
A
0 A
A Sr
A Sr
1 A
Data Byte
P
Address
Read Sequential Bytes
Slave
Address
Register
Address
Slave
Address
N
A
S
0 A
1 A Data Byte 1
. . .
Data Byte N
P
2
Figure 8. Data Format of I C Interface
Fault Detection and Diagnostics
Fault Detection
The MAX20461 features advanced device protection features with automatic fault handing and recovery. Table 12
summarizes the conditions that generate a fault, and the actions taken by the device. For all variants, the FAULT output
remains asserted as long as a fault condition persists.
2
For I C variants, the IRQ registers provide detailed information on the source of the fault condition, and the IRQMASK
2
registers allow selection of the criteria for assertion of the I C Interrupt pin, INT. The IRQ register bits clear when read.
However, the IRQ bits that represent a present fault condition continue to reassert after they are cleared, so long as the
fault condition persists. If the IRQMASK registers are configured to assert INT for a present fault, the INT pin deasserts
when the IRQ register that asserted the interrupt is read. The INT pin subsequently reasserts if the fault condition persists.
Fault Output Pin (FAULT)
The MAX20461 features an open-drain, active-low FAULT output. The MAX20461 is designed to eliminate false FAULT
reporting by using an internal deglitch and fault blanking timer. This ensures FAULT is not incorrectly asserted during
normal operation such as starting into high-capacitance loads. The FAULT pin can be tied directly to the over-current
fault input of a hub controller or SoC.
Table 12. Fault Conditions
DEBOUNCE
PRIOR TO
ACTION
IRQ REGISTER
BITS (I C ONLY)
EVENT
ACTION TAKEN
2
Assert FAULT pin and associated IRQ bit, shut down DC-DC converter, open
Thermal
Shutdown
THM_SHD
Immediate
data switches, and disable R . When fault resolves and RETRY_TMR expires,
P
release FAULT pin, enable R and the DC-DC converter.
P
www.maximintegrated.com
Maxim Integrated | 43
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
Table 12. Fault Conditions (continued)
DEBOUNCE
PRIOR TO
ACTION
IRQ REGISTER
BITS (I C ONLY)
EVENT
ACTION TAKEN
2
Thermal
Warning/
Foldback
Assert associated IRQ bit and reduce Type-C R by one step. When fault
P
resolves and RETRY_TMR expires, reset Type-C to CC_SRC_CUR.
THM_WARN
IN_OV
20 ms
Assert FAULT pin and associated IRQ bit, shut down DC-DC converter, open
IN
data switches, disable R , and reset BC1.2. When fault resolves and
P
Immediate
Overvoltage
RETRY_TMR expires, release FAULT pin, close data switches, enable R and
P
the DC-DC converter.
Assert FAULT pin and associated IRQ bit, shut down DC-DC converter, open
HVDP/
HVDM
Overvoltage
data switches, disable R , and reset BC1.2. When fault resolves and
P
DATA_OV
Immediate
16 ms
RETRY_TMR expires, release FAULT pin, close data switches, enable R and
P
the DC-DC converter.
Assert FAULT pin and associated IRQ bit after overcurrent condition persists for
16ms. When overcurrent resolves and RETRY_TMR expires, release FAULT
pin.
USB DC
Overcurrent
VBUS_ILIM
ILIM_ITRIP = 0:
Assert FAULT pin and associated IRQ bit, shut down DC-DC converter, and
disable R after overcurrent and undervoltage condition persists for 16ms.
P
USB DC
Release FAULT pin, enable R and DC-DC converter once RETRY_TMR
P
Overcurrent
and SENSN
< 4.38V
expires after shutdown.
VBUS_ILIM_UV
16 ms
2
I C variant and ILIM_ITRIP = 1:
Assert FAULT pin and associated IRQ bit after overcurrent condition persists for
16ms. When overcurrent resolves and RETRY_TMR expires, release FAULT
pin.
Assert FAULT pin and associated IRQ bit after undervoltage condition persists
for 16ms. When undervoltage resolves and RETRY_TMR expires, release
FAULT pin.
SENSN <
4.38V
VBUS_UV
16 ms
USB DC
Overcurrent
and SENSN
< 2V
Assert FAULT pin and associated IRQ bit, shut down DC-DC converter, open
VBUS_SHT_GND
Immediate
data switches, and disable R . Release FAULT pin, enable R and DC-DC
P
P
converter once RETRY_TMR expires after shutdown.
LX
Overcurrent
for 4
Assert FAULT pin and associated IRQ bit, shut down DC-DC converter, open
Consecutive VBUS_SHT_GND
Immediate
data switches, and disable R . Release FAULT pin, enable R and DC-DC
P
P
Cycles
converter once RETRY_TMR expires after shutdown.
and SENSN
< 2V
Assert FAULT pin and associated IRQ bit, shut down DC-DC converter, open
data switches, and disable R . When fault resolves and RETRY_TMR expires,
SENSN
VBUS_OV
Overvoltage
Immediate
1 ms
P
release FAULT pin, enable R , DC-DC converter, and data switches.
P
Assert FAULT pin and associated IRQ bit, open V
FET. After overcurrent
CONN
V
CONN
VCONN_ILIM
no longer exists and RETRY_TMR expires, release FAULT pin. V
can only
CONN
Overcurrent
be re-enabled by passing through the unattached state.
V
on
Pre-
Assert FAULT pin and associated IRQ bit after overvoltage condition persists for
16ms. After overvoltage no longer exists and RETRY_TMR has expired, release
FAULT pin.
BUS
VBUS_PRE_OV
16 ms
Overvoltage
www.maximintegrated.com
Maxim Integrated | 44
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
Register Map
Summary Table
ADDRESS
NAME
MSB
LSB
USER_CMDS
THM_FL EN_DCD
SYNC_D
IR
0x00
0x01
0x02
SETUP_0[7:0]
SETUP_1[7:0]
SETUP_2[7:0]
–
VOUT[2:0]
SS_EN
DBK_EN
C
FSW[2:0]
GAIN[4:0]
ILIM_ITR
IP
–
–
–
–
ILIM[2:0]
CC_VCO
NN_EN
0x03
0x04
0x05
0x06
SETUP_3[7:0]
RETRY_TMR[1:0]
CD[1:0]
CC_ENB
CC_SRC_CUR[1:0]
CONFIG
URED
SETUP_4[7:0]
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
ADC_RE
ADC_REQUEST[7:0]
CC_REQUEST[7:0]
–
Q
CC_FOR CC_SRC
CE_ERR
_RST
EN_CC_ EN_CC_ EN_BC_ EN_CC_ EN_BC_
STATE_ ATTACH ATTACH ATTACH ATTACH
IRQ_AU
TOCLR
EN_ADC
_DONE
0x07
0x08
0x09
0x0A
IRQ_MASK_0[7:0]
IRQ_MASK_1[7:0]
IRQ_MASK_2[7:0]
IRQ_0[7:0]
–
EV
_IRQ
_IRQ
_EV
_EV
EN_VBU EN_VBU
S_PRE_ S_ILIM_
EN_VBU
S_SHT_
GND
EN_VBU EN_VBU EN_VBU
S_ILIM S_OV S_UV
EN_THM
_SHD
–
–
OV
UV
EN_VBU
S_PREB
IAS
EN_VCO EN_THM EN_IN_ EN_DAT EN_VCO
–
NN_ERR _WARN
OV
A_OV
NN_ILIM
UNCON
FIGURE
D
CC_ATT BC_ATT
CC_STA
TE_EV
CC_ATT BC_ATT ADC_DO
ACH_EV ACH_EV NE
–
ACH_IR
Q
ACH_IR
Q
VBUS_P VBUS_IL VBUS_IL VBUS_O VBUS_U VBUS_S THM_SH
0x0B
0x0C
0x0D
0x0E
IRQ_1[7:0]
–
–
–
–
RE_OV
IM_UV
IM
V
V
HT_GND
DATA_O VCONN_
ILIM
D
VBUS_P VCONN_ THM_W
IRQ_2[7:0]
–
IN_OV
REBIAS
–
ERR
ARN
V
CC_ATT BC_ATT VBMON VCONN_ VBUS_S
ACH ACH _SAFE READY TAT
STATUS_0[7:0]
STATUS_1[7:0]
–
–
CC_PIN_STATE[1:0
]
CC_STATE[3:0]
0x10
0x11
0x12
ADC_0[7:0]
ADC_1[7:0]
ADC_2[7:0]
ADC_USBI[7:0]
ADC_USBV[7:0]
ADC_TEMP[7:0]
Register Details
SETUP_0 (0x0)
www.maximintegrated.com
Maxim Integrated | 45
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
BIT
Field
7
–
–
–
6
5
4
3
2
1
0
THM_FLDB
K_EN
EN_DCDC
0b1
VOUT[2:0]
0b000
SYNC_DIR
SS_EN
Reset
0b0
Access
Type
Write, Read Write, Read
Write, Read
Write, Read Write, Read
DECODE
BITFIELD
BITS
DESCRIPTION
THM_FLDBK
_EN
Lowers the Type-C advertised current
capability when thermal warning is tripped.
0 = Disable Thermal Foldback
1 = Enable Thermal Foldback
6
DC/DC Converter Enable. Internally AND'ed
with the ENBUCK pin.
0 = Disable V
1 = Enable V
Buck Converter
Buck Converter
BUS
BUS
EN_DCDC
5
0b000 = 5V
0b001 = 9V
0b010 = 12V
0b011 = 15V
VOUT
4:2
V
BUS
Output Level Selection
0b100 = 18V (protected battery pass-through)
0b101 = 5V
0b110 = 5V
0b111 = 5V
SYNC Pin Direction Selection
Initial value set by CONFIG1 resistor.
0 = Output
1 = Input
SYNC_DIR
SS_EN
1
0
Spread Spectrum Enable
Initial value set by CONFIG1 resistor.
0 = Disable Spread Spectrum Function
1 = Enable Spread Spectrum Function
SETUP_1 (0x1)
BIT
Field
7
6
5
4
3
2
1
0
FSW[2:0]
0b000
GAIN[4:0]
0b00000
Reset
Access
Type
Write, Read
Write, Read
BITFIELD
BITS
DESCRIPTION
DECODE
0b000 = 2200 kHz
0b001 = 1200 kHz
0b010 = 790 kHz
0b011 = 600 kHz
0b100 = 488 kHz
0b101 = 410 kHz
0b110 = 350 kHz
0b111 = 310 kHz
DC/DC Convertor Switching Frequency
Selection
FSW
7:5
www.maximintegrated.com
Maxim Integrated | 46
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
BITFIELD
BITS
DESCRIPTION
DECODE
0: 0mΩ
1: 18mΩ
2: 36mΩ
3: 54mΩ
4: 72mΩ
5: 90mΩ
6: 108mΩ
7: 126mΩ
8: 144mΩ
9: 162mΩ
10: 180mΩ
11: 198mΩ
12: 216mΩ
13: 234mΩ
14: 252mΩ
15: 270mΩ
16: 288mΩ
17: 306mΩ
18: 324mΩ
19: 342mΩ
20: 360mΩ
21: 378mΩ
22: 396mΩ
23: 414mΩ
24: 432mΩ
25: 450mΩ
26: 468mΩ
27: 486mΩ
28: 504mΩ
29: 522mΩ
30: 540mΩ
31: 558mΩ
The gain of the voltage correction applied to
the buck converter output (based on DC load
GAIN
4:0
sensed by current sense amp). R
33mΩ.
=
SENSE
SETUP_2 (0x2)
BIT
Field
7
–
–
6
–
–
5
–
–
4
3
–
–
2
1
0
ILIM_ITRIP
0b0
ILIM[2:0]
0b111
Reset
Access
Type
–
–
–
Write, Read
–
Write, Read
BITFIELD
BITS
DESCRIPTION
DECODE
Determines the buck's retry behavior under
USB DC current limit conditions.
0 = VBUS_ILIM_UV fault enabled.
1 = VBUS_ILIM_UV fault disabled.
ILIM_ITRIP
4
USB DC Current-Limit Threshold (min in Amps)
0b000 = 0.3
0b001 = 0.55
0b010 = 0.8
0b011 = 1.05
0b100 = 1.62
0b101 = 2.1
0b110 = 2.6
0b111 = 3.04
USB DC Current-Limit Threshold, R
33mΩ.
=
SENSE
ILIM
2:0
www.maximintegrated.com
Maxim Integrated | 47
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
SETUP_3 (0x3)
BIT
7
6
5
4
3
2
1
0
CC_VCON
N_EN
Field
RETRY_TMR[1:0]
0b00
CD[1:0]
CC_ENB
0b0
CC_SRC_CUR[1:0]
0b01
Reset
0b1
Access
Type
Write, Read
Write, Read
Write, Read Write, Read
Write, Read
BITFIELD
BITS
DESCRIPTION
DECODE
0b00 = 2.0s
0b01= 1.0s
0b10 = 0.5s
0b11= 16ms
RETRY_TM
R
Determines the length of the RETRY timer
after a fault condition.
7:6
5:4
BC1.2 Charge Detection Configuration
Selection.
0b00 = High Speed Pass Through (SDP)
0b01 = Auto-CDP
0b10 = Reserved
CD
This register is pre-loaded based on the part
number variant and the status of the
BCMODE pin.
0b11 = Reserved
0 = Enable
1 = Disable
CC_ENB
3
2
Disable Type-C Detection
MAX20461A: Not Used
CC_VCONN
_EN
0 = Disable V
1 = Enable V
pass-through.
pass-through.
CONN
CONN
MAX20461: Enable V
pass-through
CONN
00 = 0.5A
01 = 1.5A
10 = 3.0A
11 = 0.5A
CC_SRC_C
UR
Type-C DFP source pullup current
advertisement (R )
1:0
P
SETUP_4 (0x4)
BIT
7
–
–
–
6
–
–
–
5
4
–
–
–
3
–
–
–
2
–
–
–
1
–
–
–
0
CONFIGUR
ED
Field
–
–
–
Reset
0b0
Access
Type
Write, Read
BITFIELD
BITS
DESCRIPTION
DECODE
2
I C configuration complete indicator
2
CONFIGURE
D
Upon power-up, the buck converter is
prevented from turning on until this bit is
written to a one, indicating the part is fully
configured for its intended mode of operation.
0 = I C Configuration Pending
0
2
1 = I C Configuration Complete
ADC_REQUEST (0x5)
BIT
Field
7
–
–
6
–
–
5
–
–
4
–
–
3
–
–
2
–
–
1
–
–
0
ADC_REQ
0b0
Reset
Access
Type
–
–
–
–
–
–
–
Write, Read
www.maximintegrated.com
Maxim Integrated | 48
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
BITFIELD
BITS
DESCRIPTION
DECODE
ADC V/I Sample Request
When a one is written, ADC V/I sampling is
initiated. This bit is cleared once the
requested sampling is complete and the ADC 1 = ADC Sample Requested
results are updated. The status of the ADC
conversion (data ready) can be monitored in
the IRQ0 register.
0 = No ADC Sample Requested
ADC_REQ
0
CC_REQUEST (0x6)
BIT
7
–
–
–
6
–
–
–
5
–
–
–
4
–
–
–
3
–
–
–
2
–
–
–
1
0
CC_FORCE CC_SRC_R
Field
_ERR
ST
Reset
0b0
0b0
Access
Type
Write, Read Write, Read
DECODE
BITFIELD
BITS
DESCRIPTION
Type-C Force Error Request
CC_FORCE_
ERR
0 = No change to current operating state.
1 = Force transition to error recovery state.
1
This is a request bit (write-only). Forces the
Type-C state machine to go through error
recovery. This bit will always read back zero.
Type-C Force Source Reset Request
CC_SRC_RS
T
This is a request bit (write-only). The Type-C
state machine will be forced back to the
UnAttached.SRC state, restarting Type-C
detection. This bit will always read back zero.
0 = No change to current operating state
1 = Force transition to UnAttached.SRC state
0
IRQ_MASK_0 (0x7)
A Read-Write register that configures which of the conditions in the IRQ_0 register will assert an Interrupt. See the
IRQ_0 register for condition descriptions.
BIT
Field
7
6
–
–
–
5
4
3
2
1
0
IRQ_AUTO
CLR
EN_CC_ST EN_CC_AT EN_BC_AT EN_CC_AT EN_BC_AT EN_ADC_D
ATE_EV
TACH_IRQ TACH_IRQ
TACH_EV
TACH_EV
ONE
Reset
0b0
0b0
0b0 0b0
0b0
0b0
0b0
Access
Type
Write, Read
Write, Read Write, Read Write, Read Write, Read Write, Read Write, Read
BITFIELD
BITS
DESCRIPTION
DECODE
0 = IRQ register flags are latched on until read.
1 = IRQ register flags are automatically cleared
when the error condition is removed.
IRQ_AUTOC
LR
7
IRQ Auto Clear
EN_CC_STA
TE_EV
0 = Not included in Interrupt
1 = Included in Interrupt
5
4
3
CC_STATE Interrupt Enable
EN_CC_ATT
ACH_IRQ
0 = Not included in Interrupt
1 = Included in Interrupt
Type-C ATTACH STATUS Interrupt Enable
BC1.2 ATTACH STATUS Interrupt Enable
EN_BC_ATT
ACH_IRQ
0 = Not included in Interrupt
1 = Included in Interrupt
www.maximintegrated.com
Maxim Integrated | 49
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
BITFIELD
BITS
DESCRIPTION
DECODE
0 = Not included in Interrupt
EN_CC_ATT
ACH_EV
2
Type-C ATTACH EVENT Interrupt Enable
BC1.2 ATTACH EVENT Interrupt Enable
ADC_DONE Interrupt Enable
1 = Included in Interrupt
EN_BC_ATT
ACH_EV
0 = Not included in Interrupt
1 = Included in Interrupt
1
0
EN_ADC_D
ONE
0 = Not included in Interrupt
1 = Included in Interrupt
IRQ_MASK_1 (0x8)
A Read-Write register that configures which of the conditions in the IRQ_1 register will assert an Interrupt. See the
IRQ_1 register for condition descriptions.
BIT
Field
7
–
–
–
6
5
4
3
2
1
0
EN_VBUS_ EN_VBUS_I EN_VBUS_I EN_VBUS_ EN_VBUS_ EN_VBUS_ EN_THM_S
PRE_OV
LIM_UV
LIM
OV
UV
SHT_GND
HD
Reset
0x0
0b0
0b0
0b0
0b0
0b0
0b0
Access
Type
Write, Read Write, Read Write, Read Write, Read Write, Read Write, Read Write, Read
BITFIELD
BITS
DESCRIPTION
DECODE
0 = Not included in Interrupt
EN_VBUS_P
RE_OV
6
VBUS_PRE_OV Interrupt Enable
1 = Included in Interrupt
EN_VBUS_IL
IM_UV
0 = Not included in Interrupt
1 = Included in Interrupt
5
4
3
2
1
0
VBUS_ILIM_UV Interrupt Enable
VBUS_ILIM Interrupt Enable
VBUS_OV Interrupt Enable
VBUS_UV Interrupt Enable
VBUS_SHT_GND Interrupt Enable
THM_SHD Interrupt Enable
EN_VBUS_IL
IM
0 = Not included in Interrupt
1 = Included in Interrupt
EN_VBUS_O
V
0 = Not included in Interrupt
1 = Included in Interrupt
EN_VBUS_U
V
0 = Not included in Interrupt
1 = Included in Interrupt
EN_VBUS_S
HT_GND
0 = Not included in Interrupt
1 = Included in Interrupt
EN_THM_SH
D
0 = Not included in Interrupt
1 = Included in Interrupt
IRQ_MASK_2 (0x9)
A Read-Write register that configures which of the conditions in the IRQ_2 register will assert an Interrupt. See the
IRQ_2 register for condition descriptions.
BIT
Field
7
–
–
–
6
–
–
–
5
4
3
2
1
0
EN_VBUS_ EN_VCON
PREBIAS
EN_THM_
WARN
EN_DATA_
OV
EN_VCON
N_ILIM
EN_IN_OV
0b0
N_ERR
Reset
0b0
0b0
0b0
0b0
0x0
Access
Type
Write, Read Write, Read Write, Read Write, Read Write, Read Write, Read
BITFIELD
BITS
DESCRIPTION
VBUS_PREBIAS Interrupt Enable
DECODE
0 = Not included in Interrupt
1 = Included in Interrupt
EN_VBUS_P
REBIAS
5
www.maximintegrated.com
Maxim Integrated | 50
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
BITFIELD
BITS
DESCRIPTION
DECODE
0 = Not included in Interrupt
MAX20461A: Not Used
EN_VCONN
_ERR
4
1 = Included in Interrupt
MAX20461: VCONN_ERR Interrupt Enable
THM_WARN Interrupt Enable
EN_THM_W
ARN
0 = Not included in Interrupt
1 = Included in Interrupt
3
2
1
0 = Not included in Interrupt
1 = Included in Interrupt
EN_IN_OV
IN_OV Interrupt Enable
EN_DATA_O
V
0 = Not included in Interrupt
1 = Included in Interrupt
DATA_OV Interrupt Enable
MAX20461A: Not Used
EN_VCONN
_ILIM
0 = Not included in Interrupt
1 = Included in Interrupt
0
MAX20461: VCONN_ILIM Interrupt Enable
IRQ_0 (0xA)
A read only register that includes flags which indicate a number of operating conditions. These flags can assert an
interrupt by setting the corresponding bit in the MASK register.
IRQ_0 holds notifications of expected operations rather than error/fault conditions.
BIT
Field
7
6
–
–
–
5
4
3
2
1
0
UNCONFIG
URED
CC_STATE CC_ATTAC BC_ATTAC CC_ATTAC BC_ATTAC ADC_DON
_EV
H_IRQ
H_IRQ
H_EV
H_EV
E
Reset
0b0
0b0
0b0
0b0
0b0
0b0
0b0
Access
Type
Read
Clears All
Read
Clears All
Read
Clears All
Read
Clears All
Read
Clears All
Read
Clears All
Read
Clears All
BITFIELD
BITS
DESCRIPTION
DECODE
0 = Device is fully configured
(CONFIGURED written to 1)
1 = Device is not fully configured
UNCONFIGU
RED
2
7
I C Unconfigured Indicator Bit
Type-C State Change Indicator
(CONFIGURED has not been written to 1)
CC_STATE_
EV
0 = No change in Type-C state since last read
1 = Type-C state has changed since last read
5
4
3
Clear on Read. Not affected by
IRQ_AUTOCLR.
Type-C ATTACH Indicator
CC_ATTACH
_IRQ
This bit indicates a Type-C device attach is
observed via the CC Pins. Applies to
Attached.SRC states. Further attach details
can be read in the STATUS registers.
0 = No Type-C device attached
1 = Type-C device attached
BC1.2 ATTACH Indicator
BC_ATTACH
_IRQ
0 = No device attached
1 = Device attached
This bit indicates a BC1.2 device attach is
observed via the HVDP/HVDM pins.
www.maximintegrated.com
Maxim Integrated | 51
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
BITFIELD
BITS
DESCRIPTION
DECODE
Type-C ATTACH Event Detected
This bit indicates a Type-C device attach was
initiated and/or terminated as observed via
the CC Pins.This bit differs from
CC_ATTACH (which indicates the current
Type-C attach status in real time) in that it is
issued only when the status changes from
unattached to attached or vice-versa.
0 = No attach or detach event detected since least
read
1 = New attach and/or detach event detected
CC_ATTACH
_EV
2
Clear on Read. Not affected by
IRQ_AUTOCLR.
BC1.2 ATTACH Event Detected
This bit indicates a BC1.2 device attach was
initiated and/or terminated as observed via
the HVDP/HVDM pins.This bit differs from
BC_ATTACH (which indicates the current
BC1.2 attach status in real time) in that it is
issued only when the status changes from
unattached to attached or vice-versa.
0 = No attach or detach event detected since least
read
1 = New attach and/or detach event detected
BC_ATTACH
_EV
1
0
Clear on Read. Not affected by
IRQ_AUTOCLR.
ADC Meaurement Complete Indicator.
Clear on Read.
0 = No new data available since least read
1 = New data available
ADC_DONE
IRQ_1 (0xB)
A read only register that includes flags which indicate a number of error conditions. These flags can assert an interrupt
by setting the corresponding bit in the MASK register.
BIT
Field
7
–
–
–
6
5
4
3
2
1
0
VBUS_PRE VBUS_ILIM
VBUS_SHT
_GND
VBUS_ILIM
0b0
VBUS_OV
0b0
VBUS_UV
0b0
THM_SHD
0b0
_OV
_UV
Reset
0b0
0b0
0b0
Access
Type
Read
Clears All
Read
Clears All
Read
Clears All
Read
Clears All
Read
Clears All
Read
Clears All
Read
Clears All
BITFIELD
BITS
DESCRIPTION
DECODE
VBUS Pre-Overvoltage Fault Detected
Asserts if overvoltage exists on VBMON
when Type-C is enabled and no Type-C
device is attached.
VBUS_PRE_
OV
0 = No event
1 = Event detected
6
Clear on Read if condition is resolved.
V
BUS
Current Limit and SENSN UV Fault
VBUS_ILIM_
UV
Detected
0 = No event
1 = Event detected
5
Disabled when ILIM_ITRIP = 1. Clear on
Read if condition is resolved.
www.maximintegrated.com
Maxim Integrated | 52
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
BITFIELD
BITS
DESCRIPTION
Current Limit Condition Detected
DECODE
V
BUS
0 = No event
1 = Event detected
VBUS_ILIM
4
Disabled when ILIM_ITRIP = 0. Clear on
Read if condition is resolved.
V
Overvoltage Fault Detected
BUS
0 = No event
1 = Event detected
VBUS_OV
VBUS_UV
3
2
1
Detected on SENSN pin. Clear on Read if
condition is resolved.
V
Under Voltage Fault Detected
BUS
0 = No event
1 = Event detected
Detected on SENSN pin. Clear on Read if
condition is resolved.
V
BUS
Short to Ground Fault Detected
VBUS_SHT_
GND
0 = No event
1 = Event detected
Detected on SENSN pin. Clear on Read if
condition is resolved.
Over Temperature Fault Detected
Asserts when the die temperature exceeds
165°C (typ). Clear on Read if condition is
resolved.
0 = No event
1 = Event detected
THM_SHD
0
IRQ_2 (0xC)
A read only register that includes flags which indicate a number of error conditions. These flags can assert an interrupt
by setting the corresponding bit in the MASK register.
BIT
7
–
–
–
6
–
–
–
5
4
3
2
1
0
VBUS_PRE VCONN_E
THM_WAR
N
VCONN_ILI
M
Field
IN_OV
0b0
DATA_OV
0b0
BIAS
RR
Reset
0b0
0b0
0b0
0b0
Access
Type
Read
Clears All
Read
Clears All
Read
Clears All
Read
Clears All
Read
Clears All
Read
Clears All
BITFIELD
BITS
DESCRIPTION
DECODE
V
BUS
Pre-Bias
VBUS_PREB
IAS
0 = No event
1 = Event detected
5
Asserts if Type-C is enabled and VBMON >
when no Type-C device is attached.
V
SAFE0V
MAX20461A: Not Used
VCONN_ER
R
0 = No event
1 = Event detected
4
3
MAX20461: V input requested and the
CONN
V
CONN
source is not within operating range.
Thermal Warning Condition Detected
Asserts when the temperature has reached
140°C (typ).
If thermal foldback is enabled, the Type-C
current advertisement is lowered one step
while this bit is asserted.
0 = No event
1 = Event detected
THM_WARN
Clear on Read if condition is resolved.
IN Pin Overvoltage Fault Detected
Clear on Read if condition is resolved.
0 = No event
1 = Event detected
IN_OV
2
1
DATA Pin Overvoltage Fault Detected
Clear on Read if condition is resolved.
0 = No event
1 = Event detected
DATA_OV
www.maximintegrated.com
Maxim Integrated | 53
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
BITFIELD
BITS
DESCRIPTION
MAX20461A: Not Used
DECODE
MAX20461: V
Detected
Overcurrent Fault
0 = No event
overcurrent monitor is only active 1 = Event detected
CONN
VCONN_ILI
M
0
The V
CONN
when V
is being sourced to a CC pin. It
CONN
is not active on the opposite CC pin.
Clear on Read if condition is resolved.
STATUS_0 (0xD)
A read only register that includes information on the current status of the IC.
BIT
Field
7
–
–
–
6
–
–
–
5
–
–
–
4
3
2
1
0
CC_ATTAC BC_ATTAC VBMON_S
VCONN_R VBUS_STA
EADY
H
H
AFE
T
Reset
0b0
0b0
0b0
0b0
0b0
Access
Type
Read Only
Read Only
Read Only
Read Only
Read Only
BITFIELD
BITS
DESCRIPTION
DECODE
Type-C ATTACH Status Indicator
This bit indicates the current Type-C attach
status via the CC pins. More details can be
read in the STATUS_1 register.
0 = No Type-C device currently attached
1 = Type-C device currently attached
CC_ATTACH
4
BC1.2 ATTACH Status Indicator
This bit indicates the current device attach
status via the HVDP/HVDM pins. More details 1 = Device currently attached
can be read in the STATUS_1 register.
0 = No device currently attached
BC_ATTACH
3
2
VBMON (V
) Safe Status Indicator
BUS
VBMON_SA
FE
Determines if the DC-DC converter can be
turned on after a Type-C attach. Only
applicable with Type-C enabled.
0 = V
1 = V
> V
< V
BUS
BUS
SAFE0V
SAFE0V
MAX20461A: Not Used
VCONN_RE
ADY
0 = V
1 = V
not observed
CONN
CONN
1
0
MAX20461: V
Asserts when Type-C is enabled and a
Detect Status Indicator
CONN
> V
VCONN_DET
V
CONN
source is detected on the V
pin.
CONN
0 = V
1 = V
not applied to receptacle
applied to receptacle (Attached.SRC)
BUS
BUS
VBUS_STAT
Type-C V
Status Indicator
BUS
STATUS_1 (0xE)
A read only register that includes information on the current status of the IC.
BIT
7
–
–
6
–
–
5
4
3
2
1
0
Field
CC_PIN_STATE[1:0]
0b00
CC_STATE[3:0]
0b0000
Reset
Access
Type
–
–
Read Only
Read Only
www.maximintegrated.com
Maxim Integrated | 54
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
BITFIELD
BITS
DESCRIPTION
DECODE
0b00 = No Attach
0b01 = R detected on CC1
CC_PIN_ST
ATE
D
5:4
Type-C Active CC Pin/Orientation Indicator
Type-C Functional Status/State Indicator
0b10 = R detected on CC2
D
0b11 = Not used
0b0000 = Disabled
0b0010 = ErrorRecovery
0b0011 = Unattached.SRC
0b0110 = AttachWait.SRC
0b1000 = Attached.SRC (CC2)
0b1100 = Attached.SRC (CC1)
CC_STATE
3:0
ADC_0 (0x10)
BIT
Field
7
6
5
4
3
2
1
0
ADC_USBI[7:0]
0x00
Reset
Access
Type
Read Only
BITFIELD
BITS
DESCRIPTION
DECODE
= ((116mV/256) * ADC_USBI)/R
I
LOAD
SENSE
ADC_USBI
7:0
USB Load Current ADC Measurement Result
(amperes)
ADC_1 (0x11)
BIT
Field
7
6
5
4
3
2
1
0
ADC_USBV[7:0]
0x00
Reset
Access
Type
Read Only
BITFIELD
BITS
DESCRIPTION
DECODE
= (19.8V/256) * ADC_USBV (volts), when
V
SENSP
ADC_USBV
7:0
USB Voltage ADC Measurement Result
VOUT[2:0] = 0b000
ADC_2 (0x12)
BIT
Field
7
6
5
4
3
2
1
0
ADC_TEMP[7:0]
0x00
Reset
Access
Type
Read Only
BITFIELD
BITS
DESCRIPTION
DECODE
Die Temp = 3.5°C * ADC_TEMP - 270 (°C)
ADC_TEMP
7:0
Die Temp ADC Measurement Result
www.maximintegrated.com
Maxim Integrated | 55
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
Applications Information
DC-DC Switching Frequency Selection
The switching frequency (f ) for MAX20461 is programmable via the CONFIG1 resistor (on standalone variants) or by
SW
2
I C register writes.
Higher switching frequencies allow for smaller PCB area designs with lower inductor values and less output capacitance.
2
Consequently, peak currents and I R losses are lower at higher switching frequencies, but core losses, gate charge
currents, and switching losses increase.
To avoid AM band interference, operation between 500kHz and 1.8MHz is not recommended.
DC-DC Input Capacitor Selection
The input capacitor supplies the instantaneous current needs of the buck converter and reduces the peak currents drawn
from the upstream power source. The input bypass capacitor is a determining factor in the input voltage ripple.
The input capacitor RMS current rating requirement (I
) is defined by the following equation:
IN(RMS)
V
× V
− V
(
)
SENSP
SUPSW
SENSP
√
I
= I
LOAD
IN RMS
(
)
V
SUPSW
I
I
has a maximum value when the input voltage equals twice the output voltage (V
= 2 · V
), so
IN(RMS)
SUPSW
SENSP
1
=
· I
. I
is the measured operating load current, while I
refers to the maximum load
LOAD(MAX)
IN(MAX)
LOAD(MAX) LOAD
2
current.
Choose an input capacitor that exhibits less than 10ºC self-heating temperature rise at the RMS input current for optimal
long-term reliability.
The input voltage ripple is composed of V (caused by the capacitor discharge) and V
(caused by the ESR of the
ESR
Q
capacitor). Use low-ESR ceramic capacitors with high ripple current capability at the input. Assume the contribution from
the ESR and capacitor discharge is equal to 50%. Calculate the input capacitance and ESR required for a specified input
voltage ripple using the following equations:
ΔV
ESR
ESR
=
IN
ΔI
L
I
+
LOAD MAX
(
)
2
where:
V
− V
× V
(
)
SUPSW
V
SENSP
SENSP
× L
ΔI =
L
× f
SUPSW SW
and:
I
× D 1 − D
V
V
(
)
LOAD MAX
(
)
SENSP
C
=
where D =
IN
ΔV × f
Q
SW
SUPSW
Where D is the buck converter duty cycle.
Bypass SUPSW with 0.1μF parallel to 10μF of ceramic capacitance close to the SUPSW and PGND pins. The ceramic
di
dt
input capacitor of a buck converter has a high , minimize the PCB current-loop area to reduce EMI. Bypass SUPSW
with 47μF of bulk electrolytic capacitance to dampen line transients.
DC-DC Output Capacitor Selection
To ensure stability and compliance with the USB and Apple specifications, follow the recommended output filters listed in
Table 13. For proper functionality, a minimum amount of ceramic capacitance must be used regardless of f . Additional
SW
www.maximintegrated.com
Maxim Integrated | 56
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
capacitance for lower switching frequencies can be low-ESR electrolytic types (< 0.25Ω).
DC-DC Output Inductor Selection
Three key inductor parameters must be considered when selecting an inductor: inductance value (L), inductor saturation
current (I
), and DC resistance (R
). To select the proper inductance value, the ratio of inductor peak-to-peak AC
SAT
DCR
current to DC average current (LIR) must be selected. A small LIR will reduce the RMS current in the output capacitor
and results in small output ripple voltage, but this requires a larger inductor. A good compromise between size and loss
is LIR = 0.35 (35%). Determine the inductor value using the equation below,
V
× V
− V
(
)
SENSP
SUPSW
SENSP
L =
V
× f
× I
× LIR
SUPSW SW
LOAD MAX
(
)
where V
and V
are typical values (such that efficiency is optimum for nominal operating conditions). Ensure
SENSP
SUPSW
the inductor I
is above the buck converter's cycle-by-cycle peak current limit.
SAT
Table 13. Recommended Output Filters For I
of 3A
LOAD
f
(kHz)
L
OUT
(μH)
RECOMMENDED C
OUT
SW
2200
1.5
22μF ceramic
488
488
248
8.2
8.2
20
3 x 22μF ceramic
22μF ceramic + low-ESR 68μF electrolytic (< 0.25Ω)
22μF ceramic + low-ESR 68μF electrolytic (< 0.25Ω)
Layout Considerations
Proper PCB layout is critical for robust system performance. See the MAX20461 EV kit datasheet for a recommended
layout. Minimize the current-loop area and the parasitics of the DC-DC conversion circuitry to reduce EMI. The input
di
dt
capacitor placement should be prioritized because in a buck converter, the ceramic input capacitor has high . Place
the input capacitor, power inductor, and output capacitor as close as possible to the IC SUPSW and PGND pins. Shorter
traces should be prioritized over wider traces.
A low-impedance ground connection between the input and output capacitor is required (route through the ground pour
on the exposed pad). Connect the exposed pad to ground. Place multiple vias in the pad to connect to all other ground
layers for proper heat dissipation. Failure to do so can result in the IC repeatedly reaching thermal shutdown. Do not
use separate power and analog ground planes. Instead, use a single common ground and manage currents through
component placement. High-frequency return current flows through the path of least impedance (through the ground pour
directly underneath the corresponding traces).
USB traces must be routed as a 90Ω differential pair with an appropriate keep-out area. Avoid routing USB traces near
clocks and high-frequency switching nodes. The length of the routing should be minimized and avoid 90° turns, excessive
vias, and RF stubs.
Determining USB System Requirements
The nominal cable resistance (with tolerance) for both the USB power wire (BUS) and return GND should be determined
from the cable manufacturer. In addition, be sure to include the resistance from any inline or PCB connectors. Determine
the desired operating temperature range for the application, and consider the change in resistance over temperature.
A typical application presents a 200mΩ BUS resistance with a matching 200mΩ resistance in the ground path. In this
application, the voltage drop at the far end of the captive cable is 800mV when the load current is 2A. This voltage
drop requires the voltage-adjustment circuitry of the IC to increase the output voltage to comply with the USB and Apple
specifications.
USB Loads
MAX20461 is compatible with both USB-compliant and non-compliant loads. A compliant USB device is not allowed to
www.maximintegrated.com
Maxim Integrated | 57
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
sink more than 30mA and must not present more than 10μF of capacitance when initially attached to the port. The device
then begins its HVD+/HVD- connection and enumeration process. After completion of the connect process, the device
can pull 100mA/150mA and must not present a capacitance greater than 10μF. This is considered the hot-inserted, USB-
compliant load of 44Ω in parallel with 10μF.
For non-compliant USB loads, the ICs can also support both a hot insertion and soft-start into a USB load of 2Ω in parallel
with 330μF.
USB Output Current Limit
The USB load current is monitored by an internal current-sense amplifier through the voltage created across R
.
SENSE
MAX20461 offers a digitally adjustable USB current-limit threshold. See SETUP_2 or Table 10 to select an appropriate
register or resistor value for the desired current limit.
Some systems require the need to supply up to 160% of I
MAX20461 current limit beyond 3.04A (min) by decreasing R
for brief periods. It is possible to increase the
using this scaling factor:
LOAD(MAX)
SENSE
3.04A
R
= 33mΩ ·
.
SENSE
1.6 · I
LOAD MAX
(
)
USB Voltage Adjustment
Figure 9 shows a DC model of the voltage-correction function of MAX20461. Without voltage adjustment (V
= 0,
ADJ
GAIN[4:0] = 0), the voltage seen by the device at the end of the cable will decrease linearly as load current increases.
To compensate for this, the output voltage of the buck converter should increase linearly with load current. The slope of
R
SENSE
SENSP is called R
such that V
= R
· I
and R
= GAIN 4 : 0 · R ·
LSB
(see Figure 10).
[
]
COMP
ADJ
COMP LOAD
COMP
33mΩ
The R
adjustment values available on MAX20461 are listed in the GAIN[4:0] register description and are based on
COMP
a 33mΩ sense resistor.
For V = V
; 0 ≤ I , R
LOAD
must equal the sum of the system resistances. Calculate the minimum
COMP
DUT
NO _ LOAD
R
for the system so that V
stays constant:
DUT
COMP
R
= R + R
+ R
+ R
+ R
CABLE _ VBUS CABLE _ GND
COMP _ SYS
LR
SENSE
PCB
Where R
+ R
is the round-trip resistance of the USB cable (including the effect from the cable
CABLE_VBUS
CABLE_GND
LR
shield, if it conducts current), R is the buck converter’s load regulation expressed in mΩ (51mΩ typ.), and R
is
PCB
the resistance of any additional V
parasitics (the V
FET, PCB trace, ferrites, and the USB connectors). Find the
BUS
BUS
setting for GAIN[4:0] using the minimum R
.
COMP
R
COMP_SYS
33mΩ
GAIN[4:0] = ceiling
·
R
R
(
)
LSB
SENSE
The nominal DUT voltage can then be estimated at any load current by:
R
SENSE
V
= V
+ R
· GAIN 4 : 0 ·
· I
− R · I
COMP _ SYS LOAD
DUT
NO _ LOAD
LSB
LOAD
33mΩ
[
]
www.maximintegrated.com
Maxim Integrated | 58
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
R
LR
R
SENSE
R
PCB
R
CABLE_VBUS
V
ADJ
+
-
+
+
V
I
V
DUT
SENSP
LOAD
-
-
+
-
V
NO_LOAD
R
CABLE_GND
Figure 9. DC Voltage Adjustment Model
GAIN[4:0]
31
6.8
VSUPSW=14V
6.6
6.4
6.2
6
RSENSE = 33mΩ
24
18
12
6
5.8
5.6
5.4
5.2
5
0
4.8
0
0.5
1
1.5
2
2.5
3
3.5
ILIM_SET = 3.14A (typ)
ILOAD(A)
Figure 10. Increase in SENSP vs. USB Current
Tuning of USB Data Lines
USB Hi-Speed mode requires careful PCB layout with 90Ω controlled differential impedance, with matched traces of
equal length and with no stubs or test points. MAX20461 includes high-bandwidth USB data switches (>1GHz). This
means data-line tuning is generally not required. However, all designs are recommended to include pads that would
allow LC components to be mounted on the data lines so that tuning can easily be performed later, if necessary. Tuning
components should be placed as close as possible to the IC data pins, on the same layer of the PCB as the IC. The
proper configuration of the tuning components is shown in Figure 11. Figure 12 shows the reference eye diagram used
in the test setup. Figure 13 shows the MAX20461 high-voltage eye diagram on the standard EVKIT with no tuning
components. Tuning inductors should be high-Q wire-wound inductors. Contact Maxim’s application team for assistance
with the tuning process for your specific application.
www.maximintegrated.com
Maxim Integrated | 59
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
12nH
12nH
4.7nH
HVD-
D-
6pF
6pF
2pF
2pF
HVD+
D+
4.7nH
Figure 11. Tuning of Data Lines
TIME(ns)
Figure 12. Near-Eye Diagram (with No Switch)
TIME(ns)
Figure 13. Untuned Near-Eye Diagram (with MAX20461)
USB Data Line Common-Mode Choke Placement
Most automotive applications use a USB-optimized common-mode choke to mitigate EMI signals from both leaving and
entering the module. Optimal placement for this EMI choke is at the module’s USB connector. This common-mode choke
does not replace the need for the tuning inductors previously mentioned.
ESD Protection
The high-voltage MAX20461 requires no external ESD protection. All Maxim devices incorporate ESD protection
structures to protect against electrostatic discharges encountered during handling and assembly. While competing
www.maximintegrated.com
Maxim Integrated | 60
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
solutions can latch-up and require the power to be cycled after an ESD event, the MAX20461 continues to work without
latch-up. When used with the configuration shown in the Typical Application Circuit, the MAX20461 is characterized for
protection to the following limits:
● ±25kV ISO 10605 (330pF, 2kΩ) Air Gap
● ±8kV ISO 10605 (330pF, 2kΩ) Contact
● ±15kV IEC 61000-4-2 (150pF, 330Ω) Air Gap
● ±8kV IEC 61000-4-2 (150pF, 330Ω) Contact
● ±15kV ISO 10605 (330pF, 330Ω) Air Gap
● ±8kV ISO 10605 (330pF, 330Ω) Contact
Note: All application-level ESD testing is performed on the standard evaluation kit with 1m captive cable.
ESD Test Conditions
ESD performance depends on a variety of conditions. Contact Maxim for test setup, test methodology, and test results.
Human Body Model
Figure 14 shows the Human Body Model, and Figure 16 shows the current waveform it generates when discharged
into a low impedance. This model consists of a 100pF capacitor charged to the ESD voltage of interest, which is then
discharged into the device through a 1.5kΩ resistor.
IEC 61000-4-2
The IEC 61000-4-2 standard covers ESD testing and performance of finished equipment. MAX20461 helps users design
equipment that meets Level 4 of IEC 61000-4-2. The main difference between tests done using the Human Body
Model and IEC 61000-4-2 is a higher peak current in IEC 61000-4-2. Because the series resistance is lower in the IEC
61000-4-2 ESD test model Figure 15, the ESD withstand-voltage measured to this standard is generally lower than that
measured using the Human Body Model. Figure 17 shows the current waveform for the 8kV, IEC 61000-4-2 Level 4 ESD
Contact Discharge test. The Air Gap Discharge test involves approaching the device with a charged probe. The Contact
Discharge method connects the probe to the device before the probe is energized.
RC
RD
1MΩ
1500Ω
CHARGE-CURRENT-LIMIT
RESISTOR
DISCHARGE
RESISTANCE
HIGH-
VOLTAGE
DC
DEVICE
UNDER
TEST
CS
STORAGE
CAPACITOR
100pF
SOURCE
Figure 14. Human Body ESD Test Model
www.maximintegrated.com
Maxim Integrated | 61
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
RC
RD
50MΩ to 100MΩ
330Ω
CHARGE-CURRENT-LIMIT
RESISTOR
DISCHARGE
RESISTANCE
HIGH-
VOLTAGE
DC
DEVICE
UNDER
TEST
CS
STORAGE
CAPACITOR
150pF
SOURCE
Figure 15. IEC 61000-4-2 ESD Test Model
I
(AMPS)
PEAK
PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)
I
100%
90%
r
36.8%
10%
0
TIME
0
t
RL
t
DL
Figure 16. Human Body Current Waveform
I
(AMPS)
PEAK
100%
90%
10%
t
t
R
= 0.7ns TO 1ns
30ns
60ns
Figure 17. IEC 61000-4-2 Current Waveform
www.maximintegrated.com
Maxim Integrated | 62
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
Typical Application Circuits
Typical Application Circuit
4
4
+3.3V
USB I/O
VOLTAGE
+VDD
11
4
IN
MAX20461
RX/TX
1µF
4
RX/TX
1kΩ
100kΩ
100kΩ
USB-C RECEPTACLE
3V3
USB3 MUX
A11
SBU1
SBU2
8
1kΩ
100kΩ
CC_POL (SHIELD)
A10
15
16
12
14
4
4
SCL (CONFIG3)
SCL
A2
1Optional
TX1+
TX1-
RX1+
RX1-
A3
SDA (CONFIG2)
INT (ATTACH)
FAULT
SDA
INT
4
1
B11
B10
RX1/TX1
AGND
GPIO
GPIO
B2
18
25
ENBUCK
HVEN
TX2+
TX2-
RX2+
RX2-
B3
4
1kΩ
24
4
CONFIG1
FROM ACC OR GPIO
A11
A10
RX2/TX2
17
13
3
BCMODE
SYNC
GPIO
R
CONFIG1
SYNC
IN/OUT
LOW
VOLTAGE
MCU OR
1Optional
+VCONN
2
4
A5
B5
CC1
CC2
CC1
CC2
VCONN
ASIC WITH
INTEGRATED
USB PHY
1µF
6
7
10
9
A7
B7
HVD-
D-
D+
D-
D-
D-
2Tuning
2Tuning
A6
B6
HVD+
D+
D+
D+
28
31
30
29
5
VBMON
G_DMOS
SENSN
SENSP
AGND
BIAS
32
2.2µF
19
BST
0.1µF
1.5µH
33mΩ
20
21
26
27
LX
LX
SUPSW
SUPSW
VBUS
VBAT
22µF
0.1µF
10µF
47µF
SHIELD
22
23
PGND
PGND
EP
3OPTIONAL
1DEPENDENT ON THE TYPE-C SOURCE VCONN AND USB3 DESIGN REQUIREMENTS.
2SEE “TUNING OF USB DATA LINES” FOR MORE INFORMATION.
3OPTIONAL EXTERNAL ISOLATION FET.
www.maximintegrated.com
Maxim Integrated | 63
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
Ordering Information
STARTUP MODE
2
PART NUMBER
TEMP RANGE
PIN-PACKAGE
I C
V
CONN
(BCMODE PIN = 0)
MAX20461ATJA/V+
MAX20461ATJD/V+
MAX20461AATJA/V+
MAX20461AATJD/V+
Yes
No
Yes
-40ºC to +125ºC
32 TQFN-EP*
SDP Mode
Yes
No
No
/V Denotes Automotive Qualified Parts
+ Denotes a lead(Pb)-free/RoHS-compliant package.
* Denotes Exposed Pad.
www.maximintegrated.com
Maxim Integrated | 64
MAX20461
Automotive High-Current Step-Down Converter
with USB-C Protection/Host Charger
Revision History
REVISION REVISION
PAGES
DESCRIPTION
CHANGED
NUMBER
DATE
0
7/18
Initial release
—
Updated General Description, Simplified Block Diagram, Absolute Maximum
Ratings, Package Information, TOCs 4, 7–10, 13, 17, 18, 25, Pin Configuration, Pin
Description, Figure 1, CC Attachment and VBUS Discharge diagram, Detailed
Description, USB Type-C, VCONN, Figure 2, VBUS, External FET Gate Drive
(G_DMOS Pin), System Enable (HVEN), Linear Regulator Output (BIAS), Maximum
Duty-Cycle Operation, Reset Behavior, Output Short-Circuit Protection, Figure 3,
USB Host Adapter Emulator, I2C Configuration (CONFIG1 and I2C), I2C
Diagnostics and Event Handling, Interrupt and Attach Output (INT(ATTACH)), Fault
Output Pin (FAULT), Table 11, Register Map, SETUP_3 (0x3), SETUP_4 (0x04),
CC_REQUEST (0x06), IRQ_MASK_0 (0x07), IRQ_0 (0xA), STATUS_0 (0xD),
STATUS_1 (0xE), DC-DC Input Capacitor Selection, DC-DC Output Capacitor
Selection, USB Voltage Adjustment, Tuning of USB Data Lines, Figure 9, Figure 10,
Typical Application Circuit, and Ordering Information.
1, 21, 23, 25, 26,
27, 29–31, 33,
35, 38–41, 44,
45, 46, 48, 49,
52, 53, 55, 57,
60, 61
1
8/18
Updated General Description, Benefits and Features, Absolute Maximum Ratings,
Package Information, Electrical Characteristics, Typical Operating Characteristics,
Functional Diagrams, Detailed Description, Register Details, and Applications
Information.
1, 6, 7, 9, 10, 12,
14, 15, 19, 21,
27–30, 38, 41,
44, 51, 57
2
4/20
Added MAX20461A. Updated Benefits and Features, Simplified Block Diagram,
Absolute Maximum Ratings, Electrical Characteristics, Pin Configuration, Pin
Description, DCP Reset Behavior and Timing Diagram, ENBUCK Reset Behavior
and Timing Diagram, ATTACH Logic Diagram, CC Attachment and VBUS
Discharge, Detailed Block Diagram, CC Pulldown Response, VCONN, External FET
Gate Drive (G_DMOS Pin), Power-On Sequencing, Switching Frequency
Configuration, Switching Frequency Synchronization (SYNC Pin), CONFIG2 and
CONFIG3 Pin Table (Standalone Variants), Fault Conditions, SYNC_DIR bit, SS_EN
bit, CD bit, Ordering Information.
3
4
6/20
1–63
1–65
Updated USB Type-C functionality to meet latest specifications (search for
12/20
t
). Improved SYNC pin logic for multi-port applications (search for SYNC).
DIS_DET
Expanded design methods for overcurrent flexibility (search for I
).
LOAD(MAX)
For pricing, delivery, and ordering information, please visit Maxim Integrated’s online storefront at https://www.maximintegrated.com/en/storefront/storefront.html.
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent
licenses are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max
limits) shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
© 2021 Maxim Integrated Products, Inc.
相关型号：
©2020 ICPDF网 联系我们和版权申明