TPS628511 [TI]
TPS62851x 2.7-V to 6-V, 0.5-A / 1-A / 2-A Step-Down Converter in SOT583 Package;
| 型号： | TPS628511 |
| 厂家： | 
TEXAS INSTRUMENTS |
| 描述： | TPS62851x 2.7-V to 6-V, 0.5-A / 1-A / 2-A Step-Down Converter in SOT583 Package |
| 文件： | 总36页 (文件大小：3042K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
TPS628510, TPS628511, TPS628512
SLUSDO4 – AUGUST 2020
TPS62851x 2.7-V to 6-V, 0.5-A / 1-A / 2-A Step-Down Converter in SOT583 Package
1 Features
3 Description
•
•
•
•
•
•
•
•
•
TJ = –40°C to +150°C
The TPS62851x is a family of pin-to-pin 0.5-A, 1-A,
and 2-A high efficiency, easy-to-use, synchronous
step-down DC/DC converters. They are based on a
peak current mode control topology. Low resistive
switches allow up to 2-A continuous output current at
high ambient temperature. The switching frequency is
internally fixed at 2.25 MHz and can also be
synchronized to an external clock in the range from
1.8 MHz to 4 MHz. In PWM/PFM mode, the
TPS62851x automatically enters Power Save Mode at
light loads to maintain high efficiency across the
whole load range. The TPS62851x provide a 1%
output voltage accuracy in PWM mode which helps
design a power supply with high output voltage
accuracy. The SS/TR pin allows setting the start-up
time or forming tracking of the output voltage to an
external source. This allows external sequencing of
different supply rails and limits the inrush current
during start-up.
Input voltage range: 2.7 V to 6 V
Quiescent current 15 µA typical
Output voltage from 0.6 V to 5.5 V
Output voltage accuracy ±1% (PWM operation)
Adjustable soft start-up to 10 ms
Forced PWM or PWM/PFM operation
Switching frequency in PWM: 2.25 MHz
Switching Frequency external sync (1.8 MHz to 4
MHz)
Precise ENABLE input allows:
– User-defined undervoltage lockout
– Exact sequencing
100% Duty cycle mode
Active output discharge
•
•
•
•
•
•
Spread spectrum clocking - optional
Foldback overcurrent protection - optional
Power-good output with window comparator
The TPS62851x are available in a SOT583 package.
2 Applications
Device Information
PART NUMBER
PACKAGE(1)
BODY SIZE (NOM)
•
•
•
•
•
•
Motor drives
Factory automation and control
Building automation
Test and measurement
Multi-function printer (MFP)
General purpose POL
2.1 mm x 1.6 mm
(incl pins)
TPS628510
SOT583
2.1 mm x 1.6 mm
(incl pins)
TPS628511
TPS628512
SOT583
SOT583
2.1 mm x 1.6 mm
(incl pins)
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
100
L
V
IN
TPS62851x
0.47mH
VOUT
2.7 V - 6 V
VIN
SW
95
CIN
2*10 mF
0603
R 1
CFF
COUT
EN
FB
90
2*10 mF
0603
MODE/SYNC
R2
R3
SS/TR
85
PG
80
VIN = 4.0 V
VIN = 5.0 V
VIN = 6.0 V
GND
75
Simplified Schematic
0
0.5
1
Output Current (A)
1.5
2
D002
Efficiency versus IOUT, VOUT = 3.3 V
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. ADVANCE INFORMATION for preproduction products; subject to change
without notice.
TPS628510, TPS628511, TPS628512
SLUSDO4 – AUGUST 2020
www.ti.com
Table of Contents
1 Features............................................................................1
2 Applications.....................................................................1
3 Description.......................................................................1
4 Revision History.............................................................. 2
5 Device Comparison Table...............................................3
6 Pin Configuration and Functions...................................4
Pin Functions.................................................................... 4
7 Specifications.................................................................. 5
7.1 Absolute Maximum Ratings........................................ 5
7.2 ESD Ratings............................................................... 5
7.3 Recommended Operating Conditions.........................5
7.4 Thermal Information....................................................5
7.5 Electrical Characteristics.............................................6
7.6 Typical Characteristics................................................8
8 Parameter Measurement Information............................9
8.1 Schematic................................................................... 9
9 Detailed Description......................................................10
9.1 Overview...................................................................10
9.2 Functional Block Diagram.........................................10
9.3 Feature Description...................................................10
9.4 Device Functional Modes..........................................11
10 Application and Implementation................................14
10.1 Application Information........................................... 14
10.2 Typical Application.................................................. 15
10.3 System Examples................................................... 25
11 Power Supply Recommendations..............................28
12 Layout...........................................................................29
12.1 Layout Guidelines................................................... 29
12.2 Layout Example...................................................... 29
13 Device and Documentation Support..........................30
13.1 Device Support....................................................... 30
13.2 Receiving Notification of Documentation Updates..30
13.3 Support Resources................................................. 30
13.4 Trademarks.............................................................30
13.5 Electrostatic Discharge Caution..............................30
13.6 Glossary..................................................................30
14 Mechanical, Packaging, and Orderable
Information.................................................................... 31
4 Revision History
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
DATE
REVISION
NOTES
August 2020
*
Initial release
Copyright © 2020 Texas Instruments Incorporated
2
Submit Document Feedback
Product Folder Links: TPS628510 TPS628511 TPS628512
TPS628510, TPS628511, TPS628512
www.ti.com
SLUSDO4 – AUGUST 2020
5 Device Comparison Table
DEVICE NUMBER
OUTPUT
Vout
FOLDBACK
SPREAD SPECTRUM
CLOCKING (SSC)
SOFT START
OUTPUT
VOLTAGE
CURRENT DISCHARGE CURRENT LIMIT
external cap on
SS/TR pin
TPS628510DRLR
TPS628511DRLR
TPS628512DRLR
0.5 A
1 A
ON
ON
ON
OFF
OFF
OFF
OFF
OFF
OFF
adjustable
adjustable
adjustable
external cap on
SS/TR pin
external cap on
SS/TR pin
2 A
Copyright © 2020 Texas Instruments Incorporated
Submit Document Feedback
3
Product Folder Links: TPS628510 TPS628511 TPS628512
TPS628510, TPS628511, TPS628512
SLUSDO4 – AUGUST 2020
www.ti.com
6 Pin Configuration and Functions
FB
GND SW
PG
1
VIN
EN
MODE
SS/TR
Figure 6-1. 8-Pin SOT583 DRL Package (Top View)
Pin Functions
PIN
I/O
DESCRIPTION
NAME
NO.
This is the enable pin of the device. Connect to logic low to disable the device. Pull high to
enable the device. Do not leave this pin unconnected.
EN
2
I
I
FB
5
8
Voltage feedback input. Connect the resistive output voltage divider to this pin.
Ground pin
GND
The device runs in PFM/PWM mode when this pin is pulled low. When the pin is pulled high,
the device runs in forced PWM mode. Do not leave this pin unconnected. The mode pin can
also be used to synchronize the device to an external frequency. See Section 7.5 for the
detailed specification for the digital signal applied to this pin for external synchronization.
MODE/SYNC
3
I
PG
6
4
O
I
Open-drain power-good output
Soft-Start / Tracking pin. An external capacitor connected from this pin to GND defines the
rise time for the internal reference voltage. The pin can also be used as an input for tracking
and sequencing - see Section 10.3.2 in this data sheet.
SS/TR
SW
VIN
7
1
This is the switch pin of the converter and is connected to the internal Power MOSFETs.
Power supply input. Make sure the input capacitor is connected as close as possible
between pin VIN and GND.
Copyright © 2020 Texas Instruments Incorporated
4
Submit Document Feedback
Product Folder Links: TPS628510 TPS628511 TPS628512
TPS628510, TPS628511, TPS628512
www.ti.com
SLUSDO4 – AUGUST 2020
7 Specifications
7.1 Absolute Maximum Ratings
over operating temperature range (unless otherwise noted)(1)
MIN
– 0.3
– 0.3
– 3
MAX
6.5
UNIT
V
Pin voltage(2)
Pin voltage(2)
Pin voltage(2)
Pin voltage(2)
Pin voltage(2)
Pin voltage(2)
Tstg
VIN
SW (DC)
VIN + 0.3
10
V
SW (AC, less than 10ns)(3)
V
FB
– 0.3
– 0.3
– 0.3
–65
4
V
SS/TR, PG
VIN + 0.3
6.5
V
EN, MODE/SYNC
Storage temperature
V
150
°C
(1) Stresses beyond those listed under Absolute Maximum Rating may cause permanent damage to the device. These are stress ratings
only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under
Recommended Operating Condition. Exposure to absolute-maximum-rated conditions for extended periods may affect device
reliability.
(2) All voltage values are with respect to the network ground terminal
(3) While switching
7.2 ESD Ratings
VALUE
UNIT
Human body model (HBM), per ANSI/ESDA/JEDEC JS-001,
all pins(1)
±2000
V(ESD)
Electrostatic discharge
V
Charged device model (CDM), per JEDEC
specificationJESD22-C101, all pins(2)
±750
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
(2) JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.
7.3 Recommended Operating Conditions
Over operating temperature range (unless otherwise noted)
MIN
2.7
0.6
0.32
8
NOM
MAX
6
UNIT
VIN
Input voltage range
V
V
VOUT
L
Output voltage range
5.5
1.2
200
Effective inductance
0.47
10
μH
μF
μF
mA
°C
COUT
CIN
Effective output capacitance(1)
Effective input capacitance(1)
Sink current at PG pin
Junction temperature
5
10
ISINK_PG
TJ
0
2
–40
150
(1) The values given for all the capacitors in the table are effective capacitance, which includes the DC bias effect. Due to the DC bias
effect of ceramic capacitors, the effective capacitance is lower than the nominal value when a voltage is applied. Please check the
manufacturer´s DC bias curves for the effective capacitance vs DC voltage applied. Further restrictions may apply. Please see the
feature description for COMP/FSET about the output capacitance vs compensation setting and output voltage.
7.4 Thermal Information
TPS62851x
TPS62851x
DRL (EVM)
8 PINS
60
THERMAL METRIC(1)
DRL (JEDEC)(2)
UNIT
8 PINS
110
RθJA
Junction-to-ambient thermal resistance
Junction-to-case (top) thermal resistance
Junction-to-board thermal resistance
°C/W
°C/W
°C/W
RθJC(top)
RθJB
41.3
20
n/a
n/a
Copyright © 2020 Texas Instruments Incorporated
Submit Document Feedback
5
Product Folder Links: TPS628510 TPS628511 TPS628512
TPS628510, TPS628511, TPS628512
www.ti.com
UNIT
SLUSDO4 – AUGUST 2020
TPS62851x
TPS62851x
DRL (EVM)
8 PINS
n/a
THERMAL METRIC(1)
DRL (JEDEC)(2)
8 PINS
0.8
ΨJT
Junction-to-top characterization parameter
°C/W
°C/W
°C/W
YJB
Junction-to-board characterization parameter
Junction-to-case (bottom) thermal resistance
20
n/a
RθJC(bot)
n/a
n/a
(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application
report.
(2) JEDEC standard PCB with 4 layers, no thermal vias
7.5 Electrical Characteristics
Over operating junction remperature range (TJ = -40°C to +150°C) and VIN = 2.7 V to 6 V. Typical values at VIN
5 V and TJ = 25°C. (unless otherwise noted)
=
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
SUPPLY
EN = VIN, no load, device not switching,
MODE = GND, VOUT = 0.6 V
IQ
Quiescent current
17
34
48
μA
μA
EN = GND, Nominal value at TJ = 25°C,
Max value at TJ = 150°C
ISD
Shutdown current
1.5
VIN rising
VIN falling
TJ rising
TJ falling
2.45
2.1
2.6
2.5
170
15
2.7
2.6
V
V
VUVLO
Undervoltage lock out threshold
Thermal shutdown threshold
Thermal shutdown hysteresis
°C
°C
TJSD
CONTROL and INTERFACE
VEN,IH Input threshold voltage at EN, rising edge
VEN,IL
1.05
0.96
1.1
1.0
1.15
1.05
V
V
Input threshold voltage at EN, falling edge
High-level input-threshold voltage at
MODE/SYNC
VIH
1.1
V
nA
V
IEN,LKG
VIL
ILKG
tDelay
tDelay
tRamp
tRamp
ISS/TR
Input leakage current into EN
VIH = VIN or VIL = GND
125
0.3
Low-level input-threshold voltage at
MODE/SYNC
Input leakage current into MODE/SYNC
Enable delay time
100
520
nA
µs
Time from EN high to device starts
switching; VIN applied already
135
0.8
200
Time from EN high to device starts
switching; VIN applied already, VIN ≥ 3.3 V
Enable delay time
480
1.8
µs
Time from device starts switching to
power good; device not in current limit
Output voltage ramp time
1.3
ms
Output voltage ramp time, SS/TR pin
open
Time from device starts switching to
power good; device not in current limit
90
2
150
210
2.8
µs
SS/TR source current
Tracking gain
2.5
1
uA
VFB / VSS/TR
Tracking offset
VFB when VSS/TR = 0 V
±1
mV
Frequency range on MODE/SYNC pin for
synchronization
fSYNC
1.8
20
4
MHz
Duty cycle of synchronization signal at
MODE/SYNC
80
%
µs
%
Time to lock to external frequency
50
95
UVP power good threshold voltage; DC
level
VTH_PG
VTH_PG
rising (%VFB
)
92
87
98
93
UVP power good threshold voltage; DC
level
falling (%VFB
)
90
%
Copyright © 2020 Texas Instruments Incorporated
6
Submit Document Feedback
Product Folder Links: TPS628510 TPS628511 TPS628512
TPS628510, TPS628511, TPS628512
www.ti.com
SLUSDO4 – AUGUST 2020
Over operating junction remperature range (TJ = -40°C to +150°C) and VIN = 2.7 V to 6 V. Typical values at VIN
=
5 V and TJ = 25°C. (unless otherwise noted)
PARAMETER
TEST CONDITIONS
rising (%VFB
falling (%VFB
MIN
TYP
MAX
UNIT
OVP power good threshold voltage; DC
)
107
110
113
%
level
VTH_PG
OVP power good threshold voltage; DC
)
104
107
111
%
level
VPG,OL
IPG,LKG
Low-level output voltage at PG
Input leakage current into PG
ISINK_PG = 2 mA
VPG = 5 V
0.07
0.3
V
100
nA
for a high level to low level transition on
the power good output
tPG
PG deglitch time
40
µs
OUTPUT
VFB
Feedback voltage
0.6
1
V
nA
%
IFB,LKG
VFB
Input leakage current into FB
Feedback voltage accuracy
VFB = 0.6 V
70
1
PWM, VIN ≥ VOUT + 1 V
-1
-1
PFM, VIN ≥ VOUT + 1 V, VOUT ≥ 1.5 V,
CO,eff ≥ 10 µF, L = 0.47 µH
VFB
VFB
VFB
Feedback voltage accuracy
2
3
4
%
%
%
PFM, VIN ≥ VOUT + 1 V, VOUT < 1.5 V
, CO,eff ≥ 10 µF, L = 0.47 µH
Feedback voltage accuracy
-1
-4
Feedback voltage accuracy with voltage
tracking
VIN ≥ VOUT + 1 V, VSS/TR = 0.3 V
Load regulation
PWM
0.05
0.02
%/A
%/V
Ω
Line regulation
PWM, IOUT = 1 A, VIN ≥ VOUT + 1 V
RDIS
fSW
ton,min
ton,min
Output discharge resistance
PWM Switching frequency
Minimum on-time of high-side FET
Minimum on-time of low-side FET
100
2.475
50
2.025
2.25
35
MHz
ns
VIN = 3.3 V, TJ = -40°C to 125°C
VIN ≥ 5 V
10
ns
High-side FET on-resistance
65
33
120
mΩ
RDS(ON)
Low-side FET on-resistance
High-side MOSFET leakage current
High-side MOSFET leakage current
Low-side MOSFET leakage current
Low-side MOSFET leakage current
SW leakage
VIN ≥ 5 V
TJ = 85°C
70
2.5
44
37
70
11
mΩ
µA
µA
µA
µA
µA
0.01
0.01
TJ = 85°C
V(SW) = 0.6V, current into SW pin
-0.05
2.85
DC value, for TPS628512; VIN = 3 V to 6
V
ILIMH
ILIMH
High-side FET switch current limit
High-side FET switch current limit
3.4
2.6
3.9
3.0
2.5
A
A
DC value, for TPS628511; VIN = 3 V to 6
V
2.1
1.6
DC value, for TPS628510; VIN = 3 V to 6
V
ILIMH
High-side FET switch current limit
Low-side FET negative current limit
2.1
A
A
ILIMNEG
DC value
-1.8
Copyright © 2020 Texas Instruments Incorporated
Submit Document Feedback
7
Product Folder Links: TPS628510 TPS628511 TPS628512
TPS628510, TPS628511, TPS628512
SLUSDO4 – AUGUST 2020
www.ti.com
7.6 Typical Characteristics
140
80
76
72
68
64
60
56
52
48
44
40
36
32
28
24
20
VIN = 2.7V
VIN = 3.3V
VIN = 5.0V
VIN = 2.7V
VIN = 3.3V
VIN = 5.0V
VIN = 6.0V
130
120
VIN = 6.0V
110
100
90
80
70
60
50
40
-40
0
25 85
Junction Temperature (°C)
125
150
-40
0
25 85
Junction Temperature (°C)
125
150
D002
D002
Figure 7-1. RDS (ON) of High-side Switch
Figure 7-2. RDS (ON) of Low-side Switch
Copyright © 2020 Texas Instruments Incorporated
8
Submit Document Feedback
Product Folder Links: TPS628510 TPS628511 TPS628512
TPS628510, TPS628511, TPS628512
www.ti.com
SLUSDO4 – AUGUST 2020
8 Parameter Measurement Information
8.1 Schematic
L
V
IN
TPS62851x
0.47mH
VOUT
2.7 V - 6 V
VIN
SW
CIN
2*10 mF
0603
R 1
CFF
COUT
EN
FB
2*10 mF
0603
MODE/SYNC
R2
R3
SS/TR
PG
GND
Figure 8-1. Measurement Setup
Table 8-1. List of Components
DESCRIPTION
REFERENCE
MANUFACTURER (1)
IC
L
TPS628512
Texas Instruments
Murata
Murata
Murata
Murata
Any
0.47-µH inductor DFE201210U
CIN
COUT
COUT
CSS
CFF
R1
2 x 10 µF / 6.3 V GRM188D70J106MA73
2 x 10 µF / 6.3 V GRM188D70J106MA73 for Vout ≥ 1 V
3 x 10 µF / 6.3 V GRM188D70J106MA73 for Vout < 1 V
4.7 nF (equal to 1-ms start-up ramp); GCM188R72A472KA37
10 pF
Any
Depending on VOUT
Any
R2
Depending on VOUT
Any
R3
100 kΩ
Any
(1) See the Section 13.1.1.
Copyright © 2020 Texas Instruments Incorporated
Submit Document Feedback
9
Product Folder Links: TPS628510 TPS628511 TPS628512
TPS628510, TPS628511, TPS628512
SLUSDO4 – AUGUST 2020
www.ti.com
9 Detailed Description
9.1 Overview
The TPS62851x synchronous switch mode power converters are based on a peak current mode control
topology. The control loop is internally compensated.
The regulation network achieves fast and stable operation with small external components and low ESR ceramic
output capacitors. The devices can be operated without a feedforward capacitor on the output voltage divider,
however, using a typically 10-pF feedforward capacitor improves transient response.
The devices support forced fixed frequency PWM operation with the MODE pin tied to a logic high level. The
frequency is defined as 2.25 MHz internally fixed. Alternatively, the devices can be synchronized to an external
clock signal in a range from 1.8 MHz to 4 MHz, applied to the MODE pin with no need for additional passive
components. An internal PLL allows you to change from internal clock to external clock during operation. The
synchronization to the external clock is done on a falling edge of the clock applied at MODE to the rising edge on
the SW pin. This allows a roughly 180° phase shift when the SW pin is used to generate the synchronization
signal for a second converter. When the MODE pin is set to a logic low level, the device operates in power save
mode (PFM) at low output current and automatically transfers to fixed frequency PWM mode at higher output
current. In PFM mode, the switching frequency decreases linearly based on the load to sustain high efficiency
down to very low output current.
9.2 Functional Block Diagram
VIN
SW
Bias
Regulator
Gate Drive and Control
Oscillator
Ipeak
Izero
EN
MODE
gm
GND
FB
Device
Control
PG
+
-
Bandgap
SS/TR
Thermal
Shutdown
9.3 Feature Description
9.3.1 Precise Enable (EN)
The voltage applied at the enable pin of the TPS62851x is compared to a fixed threshold of 1.1 V for a rising
voltage. This allows you to drive the pin by a slowly changing voltage and enables the use of an external RC
network to achieve a power-up delay.
The Precise Enable input provides a user-programmable undervoltage lockout by adding a resistor divider to the
input of the Enable pin.
The enable input threshold for a falling edge is typically 100 mV lower than the rising edge threshold. The
TPS62851x starts operation when the rising threshold is exceeded. For proper operation, the enable (EN) pin
must be terminated and must not be left floating. Pulling the enable pin low forces the device into shutdown, with
Copyright © 2020 Texas Instruments Incorporated
10
Submit Document Feedback
Product Folder Links: TPS628510 TPS628511 TPS628512
TPS628510, TPS628511, TPS628512
www.ti.com
SLUSDO4 – AUGUST 2020
a shutdown current of typically 1 μA. In this mode, the internal high-side and low-side MOSFETs are turned off
and the entire internal control circuitry is switched off.
9.3.2 MODE / SYNC
When MODE/SYNC is set low, the device operates in PWM or PFM mode, depending on the output current. The
MODE/SYNC pin allows you to force PWM mode when set high. The pin also allows you to apply an external
clock in a frequency range from 1.8 MHz to 4 MHz for external synchronization. The specifications for the
minimum on-time and minimum off-time have to be observed when setting the external frequency. The external
clock must be set to about 2.25 MHz initially and then increased or decreased to the desired frequency. This
ensures a low distortion of the output voltage when the external frequency is applied.
9.3.3 Spread Spectrum Clocking (SSC)
The device offers spread spectrum clocking as an option. When SSC is enabled, the switching frequency is
randomly changed in PWM mode when the internal clock is used. The frequency variation is typically between
the nominal switching frequency and up to 288 kHz above the nominal switching frequency. When the device is
externally synchronized by applying a clock signal to the MODE/SYNC pin, the TPS62851x follows the external
clock and the internal spread spectrum block is turned off. SSC is also disabled during soft start.
9.3.4 Undervoltage Lockout (UVLO)
If the input voltage drops, the undervoltage lockout prevents misoperation of the device by switching off both the
power FETs. When enabled, the device is fully operational for input voltages above the rising UVLO threshold
and turns off if the input voltage trips below the threshold for a falling supply voltage.
9.3.5 Power Good Output (PG)
Power good is an open-drain output that requires a pullup resistor to any voltage up to the recommended input
voltage level. It is driven by a window comparator. PG is held low when the device is disabled, in undervoltage
lockout in thermal shutdown, and not in soft start. When the output voltage is in regulation hence, within the
window defined in the electrical characteristics, the output is high impedance.
VIN must remain present for the PG pin to stay low. If the power good output is not used, it is recommended to tie
to GND or leave open. The PG indicator features a de-glitch, as specified in the electrical characteristics, for the
transition from "high impedance" to "low" of its output.
Table 9-1. PG Status
EN
X
DEVICE STATUS
PG STATE
undefined
low
VIN < 2 V
low
VIN ≥ 2 V
2 V ≤ VIN ≤ UVLO OR in thermal shutdown OR VOUT not in regulation
OR device in soft start
high
high
low
VOUT in regulation
high impedance
9.3.6 Thermal Shutdown
The junction temperature (TJ) of the device is monitored by an internal temperature sensor. If TJ exceeds 170°C
(typ), the device goes into thermal shutdown. Both the high-side and low-side power FETs are turned off and PG
goes low. When TJ decreases below the hysteresis amount of typically 15°C, the converter resumes normal
operation, beginning with soft start. During a PFM pause, the thermal shutdown is not active. After a PFM pause,
the device needs up to 9 µs to detect a junction temperature that is too high. If the PFM burst is shorter than this
delay, the device does not detect a junction temperature that is too high.
9.4 Device Functional Modes
9.4.1 Pulse Width Modulation (PWM) Operation
The TPS62851x has two operating modes: Forced PWM mode is discussed in this section and PWM/PFM as
discussed in Section 9.4.2.
Copyright © 2020 Texas Instruments Incorporated
Submit Document Feedback
11
Product Folder Links: TPS628510 TPS628511 TPS628512
TPS628510, TPS628511, TPS628512
SLUSDO4 – AUGUST 2020
www.ti.com
With the MODE/SYNC pin set to high, the TPS62851x operates with pulse width modulation in continuous
conduction mode (CCM). The switching frequency is 2.25 MHz or defined by an external clock signal applied to
the MODE/SYNC pin. With an external clock applied to MODE/SYNC, the TPS62851x follows the frequency
applied to the pin. In general, the frequency range in forced PWM mode is 1.8 MHz to 4 MHz. However, the
frequency needs to be in a range the TPS62851x can operate at, taking the minimum on-time into account.
9.4.2 Power Save Mode Operation (PWM/PFM)
When the MODE/SYNC pin is low, power save mode is allowed. The device operates in PWM mode as long as
the peak inductor current is above the PFM threshold of about 0.8 A. When the peak inductor current drops
below the PFM threshold, the device starts to skip switching pulses. In power save mode, the switching
frequency decreases with the load current maintaining high efficiency.
9.4.3 100% Duty-Cycle Operation
The duty cycle of a buck converter operated in PWM mode is given as D = VOUT / VIN. The duty cycle
increases as the input voltage comes close to the output voltage and the off-time gets smaller. When the
minimum off-time of typically 10 ns is reached, the TPS62851x skips switching cycles while it approaches 100%
mode. In 100% mode, it keeps the high-side switch on continuously. The high-side switch stays turned on as
long as the output voltage is below the target. In 100% mode, the low-side switch is turned off. The maximum
dropout voltage in 100% mode is the product of the on-resistance of the high-side switch plus the series
resistance of the inductor and the load current.
9.4.4 Current Limit and Short Circuit Protection
The TPS62851x is protected against overload and short circuit events. If the inductor current exceeds the
current limit ILIMH, the high-side switch is turned off and the low-side switch is turned on to ramp down the
inductor current. The high-side switch turns on again only if the current in the low side-switch has decreased
below the low side current limit. Due to internal propagation delay, the actual current can exceed the static
current limit. The dynamic current limit is given as:
V
L
Ipeak(typ) = ILIMH
+
×tPD
(1)
where
•
•
•
•
ILIMH is the static current limit as specified in the electrical characteristics
L is the effective inductance at the peak current
VL is the voltage across the inductor (VIN - VOUT
)
tPD is the internal propagation delay of typically 50 ns
The current limit can exceed static values, especially if the input voltage is high and very small inductances are
used. The dynamic high-side switch peak current can be calculated as follows:
V
IN -VOUT
Ipeak(typ) = ILIMH
+
×50ns
(2)
9.4.5 Foldback Current Limit and Short Circuit Protection
This is valid for devices where foldback current limit is enabled.
When the device detects current limit for more than 1024 subsequent switching cycles, it reduces the current
limit from its nominal value to typically 1.3 A. Foldback current limit is left when the current limit indication goes
away. If device operation continues in current limit, it would, after 3072 switching cycles, try again full current
limit for again 1024 switching cycles.
9.4.6 Output Discharge
The purpose of the discharge function is to ensure a defined down-ramp of the output voltage when the device is
being disabled and to keep the output voltage close to 0 V when the device is off. The output discharge feature
is only active once the TPS62851x has been enabled at least once since the supply voltage was applied. The
Copyright © 2020 Texas Instruments Incorporated
12
Submit Document Feedback
Product Folder Links: TPS628510 TPS628511 TPS628512
TPS628510, TPS628511, TPS628512
www.ti.com
SLUSDO4 – AUGUST 2020
discharge function is enabled as soon as the device is disabled, in thermal shutdown, or in undervoltage lockout.
The minimum supply voltage required for the discharge function to remain active typically is 2 V. Output
discharge is not activated during a current limit or foldback current limit event.
9.4.7 Soft Start / Tracking (SS/TR)
The internal soft-start circuitry controls the output voltage slope during start-up. This avoids excessive inrush
current and ensures a controlled output voltage rise time. It also prevents unwanted voltage drops from high
impedance power sources or batteries. When EN is set high to start operation, the device starts switching after a
delay of about 200 μs then the internal reference and hence VOUT rises with a slope controlled by an external
capacitor connected to the SS/TR pin.
Leaving the SS/TR pin un-connected provides the fastest start-up ramp with 160 µs typically. A capacitor
connected from SS/TR to GND is charged with 2.5 µA by an internal current source during soft start until it
reaches the reference voltage of 0.6 V. The capacitance required to set a certain ramp-time (tramp) therefore is:
(3)
If the device is set to shutdown (EN = GND), undervoltage lockout, or thermal shutdown, an internal resistor
pulls the SS/TR pin to GND to ensure a proper low level. Returning from those states causes a new start-up
sequence.
A voltage applied at SS/TR can be used to track a master voltage. The output voltage follows this voltage in both
directions up and down in forced PWM mode. In PFM mode, the output voltage decreases based on the load
current. The SS/TR pin must not be connected to the SS/TR pin of other devices. The maximum value for CSS is
47 nF to ensure proper discharge before the device starts to ramp the output voltage.
9.4.8 Input Overvoltage Protection
When the input voltage exceeds typically 6.8 V, the device is set to PFM mode so it cannot transfer energy from
the output to the input.
Copyright © 2020 Texas Instruments Incorporated
Submit Document Feedback
13
Product Folder Links: TPS628510 TPS628511 TPS628512
TPS628510, TPS628511, TPS628512
SLUSDO4 – AUGUST 2020
www.ti.com
10 Application and Implementation
Note
Information in the following applications sections is not part of the TI component specification, and TI
does not warrant its accuracy or completeness. TI’s customers are responsible for determining
suitability of components for their purposes. Customers should validate and test their design
implementation to confirm system functionality.
10.1 Application Information
10.1.1 Programming the Output Voltage
The output voltage of the TPS62851x is adjustable. It can be programmed for output voltages from 0.6 V to 5.5
V, using a resistor divider from VOUT to GND. The voltage at the FB pin is regulated to 600 mV. The value of the
output voltage is set by the selection of the resistor divider from Equation 6. It is recommended to choose
resistor values which allow a current of at least 2 µA, meaning the value of R2 must not exceed 400 kΩ. Lower
resistor values are recommended for highest accuracy and most robust design.
V
OUT
æ
ö
R1
= R
-1
FB
2 × ç
è
÷
V
ø
(4)
10.1.2 External Component Selection
10.1.2.1 Inductor Selection
The TPS62851x is designed for a nominal 0.47-µH inductor with a switching frequency of typically 2.25 MHz.
Larger values can be used to achieve a lower inductor current ripple but they can have a negative impact on
efficiency and transient response. Smaller values than 0.47 µH cause a larger inductor current ripple which
causes larger negative inductor current in forced PWM mode at low or no output current. For a higher or lower
nominal switching frequency, the inductance should be changed accordingly. See Section 7.3 for details.
The inductor selection is affected by several effects like inductor ripple current, output ripple voltage, PWM-to-
PFM transition point, and efficiency. In addition, the inductor selected has to be rated for appropriate saturation
current and DC resistance (DCR). Equation 5 calculates the maximum inductor current.
DIL(max)
IL(max) = IOUT(max)
+
2
(5)
(6)
V
OUT
æ
ö
V
1-
OUT × ç
÷
IN
1
V
è
Lmin
ø
DIL(max)
=
×
f
SW
where
•
•
•
IL(max) is the maximum inductor current
ΔIL(max) is the peak-to-peak inductor ripple current
Lmin is the minimum inductance at the operating point
Copyright © 2020 Texas Instruments Incorporated
14
Submit Document Feedback
Product Folder Links: TPS628510 TPS628511 TPS628512
TPS628510, TPS628511, TPS628512
www.ti.com
SLUSDO4 – AUGUST 2020
Table 10-1. Typical Inductors
NOMINAL
SWITCHING
FREQUENCY
INDUCTANCE
[µH]
CURRENT [A]
DIMENSIONS
TYPE
FOR DEVICE
MANUFACTURER(2)
[LxBxH] mm
(1)
DFE201210U-R47M
DFE201210U-1R0M
0.47 µH, ±20%
1 µH, ±20%
see data sheet
see data sheet
TPS628510/511 / 512
TPS628510/511 / 512
2.25 MHz
2.25 MHz
2.0 x 1.2 x 1.0
2.0x 1.2 x 1.0
Murata
Murata
DFE201210U-R68
XEL3515-561ME
XFL4015-701ME
XFL4015-471ME
0.68 µH, ±20%
0.56 µH, ±20%
0.70 µH, ±20%
0.47 µH, ±20%
see data sheet
TPS628510/511 / 512
TPS628510/511 / 512
TPS628510/511 / 512
TPS628510/511 / 512
2.25 MHz
2.25 MHz
2.25 MHz
2.25 MHz
2.0x 1.2 x 1.0
3.5 x 3.2 x 1.5
4.0 x 4.0 x 1.6
4.0 x 4.0 x 1.6
Murata
Coilcraft
Coilcraft
Coilcraft
4.5
3.3
3.5
(1) Lower of IRMS at 20°C rise or ISAT at 20% drop.
(2) See the Section 13.1.1.
Calculating the maximum inductor current using the actual operating conditions gives the minimum saturation
current of the inductor needed. A margin of about 20% is recommended to add. A larger inductor value is also
useful to get lower ripple current, but increases the transient response time and size as well.
10.1.3 Capacitor Selection
10.1.3.1 Input Capacitor
For most applications, 10-µF nominal is sufficient and is recommended. The input capacitor buffers the input
voltage for transient events and also decouples the converter from the supply. A low-ESR multilayer ceramic
capacitor (MLCC) is recommended for best filtering and must be placed between VIN and GND as close as
possible to those pins.
10.1.3.2 Output Capacitor
The architecture of the TPS62851x allows the use of tiny ceramic output capacitors with low equivalent series
resistance (ESR). These capacitors provide low output voltage ripple and are recommended. To keep its low
resistance up to high frequencies and to get narrow capacitance variation with temperature, it is recommended
to use X7R or X5R dielectric. Using a higher value has advantages like smaller voltage ripple and a tighter DC
output accuracy in power save mode.
10.2 Typical Application
L
V
IN
TPS62851x
0.47mH
VOUT
2.7 V - 6 V
CIN
VIN
SW
R 1
CFF
2*10 mF
0603
COUT
EN
FB
2*10 mF
0603
MODE/SYNC
R2
R3
SS/TR
PG
GND
Figure 10-1. Typical Application for Indy
10.2.1 Design Requirements
The design guidelines provide a component selection to operate the device within the recommended operating
conditions.
Copyright © 2020 Texas Instruments Incorporated
Submit Document Feedback
15
Product Folder Links: TPS628510 TPS628511 TPS628512
TPS628510, TPS628511, TPS628512
SLUSDO4 – AUGUST 2020
www.ti.com
10.2.2 Detailed Design Procedure
V
OUT
æ
ö
R1
= R
-1
FB
2 × ç
è
÷
V
ø
(7)
With VFB = 0.6 V:
Table 10-2. Setting the Output Voltage
NOMINAL OUTPUT VOLTAGE
VOUT
R1
R2
CFF
EXACT OUTPUT VOLTAGE
0.8 V
1.0 V
1.1 V
1.2 V
1.5 V
1.8 V
2.5 V
3.3 V
16.9 kΩ
20 kΩ
51 kΩ
30 kΩ
47 kΩ
68 kΩ
51 kΩ
40.2 kΩ
15 kΩ
19.6 kΩ
10 pF
10 pF
10 pF
10 pF
10 pF
10 pF
10 pF
10 pF
0.7988 V
1.0 V
39.2 kΩ
68 kΩ
1.101 V
1.2 V
76.8 kΩ
80.6 kΩ
47.5 kΩ
88.7 kΩ
1.5 V
1.803 V
2.5 V
3.315 V
Copyright © 2020 Texas Instruments Incorporated
16
Submit Document Feedback
Product Folder Links: TPS628510 TPS628511 TPS628512
TPS628510, TPS628511, TPS628512
www.ti.com
SLUSDO4 – AUGUST 2020
10.2.3 Application Curves
All plots have been taken with a nominal switching frequency of 2.25 MHz when set to PWM mode, unless
otherwise noted. The BOM is according to Table 8-1.
100
95
90
85
80
75
70
65
60
55
50
100
95
90
85
80
75
VIN = 4.0 V
VIN = 5.0 V
VIN = 6.0 V
VIN = 4.0 V
VIN = 5.0 V
VIN = 6.0 V
0
0.5
1
Output Current (A)
1.5
2
100m
1m
10m 100m
Output Current (A)
1
D002
D002
VOUT = 3.3 V
PWM
TA = 25°C
VOUT = 3.3 V
PFM
TA = 25°C
Figure 10-3. Efficiency versus Output Current
Figure 10-2. Efficiency versus Output Current
100
95
90
85
80
75
70
95
90
85
65
60
55
50
VIN = 2.7 V
VIN = 3.3 V
VIN = 4.0 V
VIN = 5.0 V
VIN = 6.0 V
VIN = 2.7 V
VIN = 3.3 V
VIN = 4.0 V
VIN = 5.0 V
VIN = 6.0 V
80
75
100m
1m
10m 100m
Output Current (A)
1
0
0.5
1
Output Current (A)
1.5
2
D002
D002
VOUT = 1.8 V
PFM
TA = 25°C
VOUT = 1.8 V
PWM
TA = 25°C
Figure 10-4. Efficiency versus Output Current
Figure 10-5. Efficiency versus Output Current
100
95
90
85
80
75
70
90
85
80
65
60
55
50
VIN = 2.7 V
VIN = 3.3 V
VIN = 4.0 V
VIN = 5.0 V
VIN = 6.0 V
VIN = 2.7 V
VIN = 3.3 V
VIN = 4.0 V
VIN = 5.0 V
VIN = 6.0 V
75
70
100m
1m
10m 100m
Output Current (A)
1
0
0.5
1
Output Current (A)
1.5
2
D002
D002
VOUT = 1.1 V
PFM
TA = 25°C
VOUT = 1.1 V
PWM
TA = 25°C
Figure 10-6. Efficiency versus Output Current
Figure 10-7. Efficiency versus Output Current
Copyright © 2020 Texas Instruments Incorporated
Submit Document Feedback
17
Product Folder Links: TPS628510 TPS628511 TPS628512
TPS628510, TPS628511, TPS628512
SLUSDO4 – AUGUST 2020
www.ti.com
90
85
80
75
70
65
60
55
50
45
40
90
85
80
75
70
65
60
VIN = 2.7 V
VIN = 2.7 V
VIN = 3.3 V
VIN = 4.0 V
VIN = 5.0 V
VIN = 3.3 V
VIN = 4.0 V
VIN = 5.0 V
0
0.5
1
Output Current (A)
1.5
2
100m
1m
10m
Output Current (A)
100m
1
D002
D002
VOUT = 0.6 V
PWM
TA = 25°C
VOUT = 0.6 V
PFM
TA = 25°C
Figure 10-9. Efficiency versus Output Current
Figure 10-8. Efficiency versus Output Current
3.33
3.324
3.318
3.312
3.306
3.3
3.33
3.324
3.318
3.312
3.306
3.3
3.294
3.288
3.294
3.288
3.282
3.282
VIN = 4.0 V
VIN = 5.0 V
VIN = 6.0 V
VIN = 4.0 V
VIN = 5.0 V
VIN = 6.0 V
3.276
3.27
3.276
3.27
100m
1m
10m
Output Current (A)
100m
1
2
100m
1m
10m
Output Current (A)
100m
1
2
D002
D002
VOUT = 3.3 V
PWM
TA = 25°C
VOUT = 3.3 V
PFM
TA = 25°C
Figure 10-11. Output Voltage versus Output
Current
Figure 10-10. Output Voltage versus Output
Current
1.82
1.816
1.812
1.808
1.804
1.8
1.82
1.816
1.812
1.808
1.804
1.8
1.796
1.796
1.792
1.788
1.784
1.78
1.792
1.788
1.784
1.78
VIN = 2.7 V
VIN = 3.3 V
VIN = 4.0 V
VIN = 5.0 V
VIN = 6.0 V
VIN = 2.7 V
VIN = 3.3 V
VIN = 4.0 V
VIN = 5.0 V
VIN = 6.0 V
100m
1m
10m
Output Current (A)
100m
1
2
100m
1m
10m
Output Current (A)
100m
1
2
D002
D002
VOUT = 1.8 V
PFM
TA = 25°C
VOUT = 1.8 V
PWM
TA = 25°C
Figure 10-12. Output Voltage versus Output
Current
Figure 10-13. Output Voltage versus Output
Current
Copyright © 2020 Texas Instruments Incorporated
18
Submit Document Feedback
Product Folder Links: TPS628510 TPS628511 TPS628512
TPS628510, TPS628511, TPS628512
www.ti.com
SLUSDO4 – AUGUST 2020
1.11
1.108
1.106
1.104
1.102
1.1
1.11
1.108
1.106
1.104
1.102
1.1
1.098
1.096
1.094
1.092
1.09
1.098
1.096
1.094
1.092
1.09
VIN = 2.7 V
VIN = 3.3 V
VIN = 4.0 V
VIN = 5.0 V
VIN = 6.0 V
VIN = 2.7 V
VIN = 3.3 V
VIN = 4.0 V
VIN = 5.0 V
VIN = 6.0 V
100m
1m
10m
Output Current (A)
100m
1
2
100m
1m
10m
Output Current (A)
100m
1
2
D002
D002
VOUT = 1.1 V
PFM
TA = 25°C
VOUT = 1.1 V
PWM
TA = 25°C
Figure 10-14. Output Voltage versus Output
Current
Figure 10-15. Output Voltage versus Output
Current
0.612
0.606
0.6045
0.603
0.6015
0.6
0.61
0.608
0.606
0.604
0.602
0.6
0.5985
0.597
VIN = 2.7 V
VIN = 3.3 V
VIN = 4.0 V
VIN = 5.0 V
VIN = 2.7 V
0.598
VIN = 3.3 V
0.5955
0.594
VIN = 4.0 V
VIN = 5.0 V
0.596
0.594
100m
1m
10m 100m
Output Current (A)
1
2
100m
1m
10m 100m
Output Current (A)
1
2
D002
D002
VOUT = 0.6 V
PWM
TA = 25°C
VOUT = 0.6 V
PFM
TA = 25°C
Figure 10-17. Output Voltage versus Output
Current
Figure 10-16. Output Voltage versus Output
Current
VOUT = 3.3 V
VIN = 5.0 V
PFM
TA = 25°C
VOUT = 3.3 V
VIN = 5.0 V
PWM
TA = 25°C
IOUT = 0.2 A to 1.8 A to 0.2 A
IOUT = 0.2 A to 1.8 A to 0.2 A
Figure 10-18. Load Transient Response
Figure 10-19. Load Transient Response
Copyright © 2020 Texas Instruments Incorporated
Submit Document Feedback
19
Product Folder Links: TPS628510 TPS628511 TPS628512
TPS628510, TPS628511, TPS628512
SLUSDO4 – AUGUST 2020
www.ti.com
VOUT = 1.8 V
VIN = 5.0 V
PFM
TA = 25°C
VOUT = 1.8 V
VIN = 5.0 V
PWM
TA = 25°C
IOUT = 0.2 A to 1.8 A to 0.2 A
IOUT = 0.2 A to 1.8 A to 0.2 A
Figure 10-20. Load Transient Response
Figure 10-21. Load Transient Response
VOUT = 1.2 V
VIN = 5.0 V
PFM
TA = 25°C
VOUT = 1.2 V
VIN = 5.0 V
PWM
TA = 25°C
IOUT = 0.2 A to 1.8 A to 0.2 A
IOUT = 0.2 A to 1.8 A to 0.2 A
Figure 10-22. Load Transient Response
Figure 10-23. Load Transient Response
VOUT = 1.0 V
VIN = 5.0 V
PFM
TA = 25°C
VOUT = 1.0 V
VIN = 5.0 V
PWM
TA = 25°C
IOUT = 0.2 A to 1.8 A to 0.2 A
IOUT = 0.2 A to 1.8 A to 0.2 A
Figure 10-24. Load Transient Response
Figure 10-25. Load Transient Response
Copyright © 2020 Texas Instruments Incorporated
20
Submit Document Feedback
Product Folder Links: TPS628510 TPS628511 TPS628512
TPS628510, TPS628511, TPS628512
www.ti.com
SLUSDO4 – AUGUST 2020
VOUT = 0.6 V
VIN = 3.3 V
PFM
TA = 25°C
VOUT = 0.6 V
VIN = 3.3 V
PWM
TA = 25°C
IOUT = 0.2 A to 1.8 A to 0.2 A
IOUT = 0.2 A to 1.8 A to 0.2 A
Figure 10-26. Load Transient Response
Figure 10-27. Load Transient Response
VOUT = 3.3 V
IOUT = 0.2 A
PFM
TA = 25°C
VOUT = 3.3 V
IOUT = 2 A
PWM
TA = 25°C
VIN = 4.5 V to 5.5 V to 4.5 V
VIN = 4.5 V to 5.5 V to 4.5 V
Figure 10-28. Line Transient Response
Figure 10-29. Line Transient Response
VOUT = 1.8 V
IOUT = 0.2 A
PFM
TA = 25°C
VOUT = 1.8 V
IOUT = 2 A
PWM
TA = 25°C
VIN = 4.5 V to 5.5 V to 4.5 V
VIN = 4.5 V to 5.5 V to 4.5 V
Figure 10-30. Line Transient Response
Figure 10-31. Line Transient Response
Copyright © 2020 Texas Instruments Incorporated
Submit Document Feedback
21
Product Folder Links: TPS628510 TPS628511 TPS628512
TPS628510, TPS628511, TPS628512
SLUSDO4 – AUGUST 2020
www.ti.com
VOUT = 1.2 V
IOUT = 0.2 A
PFM
TA = 25°C
VOUT = 1.2 V
IOUT = 2 A
PWM
TA = 25°C
VIN = 4.5 V to 5.5 V to 4.5 V
VIN = 4.5 V to 5.5 V to 4.5 V
Figure 10-32. Line Transient Response
Figure 10-33. Line Transient Response
VOUT = 1.0 V
IOUT = 0.2 A
PFM
TA = 25°C
VOUT = 1.0 V
IOUT = 2 A
PWM
TA = 25°C
VIN = 4.5 V to 5.5 V to 4.5 V
VIN = 4.5 V to 5.5 V to 4.5 V
Figure 10-34. Line Transient Response
Figure 10-35. Line Transient Response
VOUT = 0.6 V
IOUT = 0.2 A
PFM
TA = 25°C
VOUT = 0.6 V
IOUT = 2 A
PWM
TA = 25°C
VIN = 3.0 V to 3.6 V to 3.0 V
VIN = 3.0 V to 3.6 V to 3.0 V
Figure 10-36. Line Transient Response
Figure 10-37. Line Transient Response
Copyright © 2020 Texas Instruments Incorporated
22
Submit Document Feedback
Product Folder Links: TPS628510 TPS628511 TPS628512
TPS628510, TPS628511, TPS628512
www.ti.com
SLUSDO4 – AUGUST 2020
VOUT = 3.3 V
VIN = 5 V
PFM
TA = 25°C
VOUT = 3.3 V
VIN = 5 V
PWM
TA = 25°C
IOUT = 2 A
IOUT = 0.2 A
Figure 10-38. Output Voltage Ripple
Figure 10-39. Output Voltage Ripple
VOUT = 1.8 V
VIN = 5 V
PFM
TA = 25°C
VOUT = 1.8 V
VIN = 5 V
PWM
TA = 25°C
IOUT = 2 A
IOUT = 0.2 A
Figure 10-40. Output Voltage Ripple
Figure 10-41. Output Voltage Ripple
VOUT = 1.2 V
VIN = 5 V
PFM
TA = 25°C
VOUT = 1.2 V
VIN = 5 V
PWM
TA = 25°C
IOUT = 2 A
IOUT = 0.2 A
Figure 10-42. Output Voltage Ripple
Figure 10-43. Output Voltage Ripple
Copyright © 2020 Texas Instruments Incorporated
Submit Document Feedback
23
Product Folder Links: TPS628510 TPS628511 TPS628512
TPS628510, TPS628511, TPS628512
SLUSDO4 – AUGUST 2020
www.ti.com
VOUT = 1.0 V
VIN = 5 V
PFM
TA = 25°C
VOUT = 1.0 V
VIN = 5 V
PWM
TA = 25°C
IOUT = 2 A
IOUT = 0.2 A
Figure 10-44. Output Voltage Ripple
Figure 10-45. Output Voltage Ripple
VOUT = 0.6 V
VIN = 3.3 V
PFM
TA = 25°C
VOUT = 0.6 V
VIN = 3.3 V
PWM
TA = 25°C
IOUT = 2 A
IOUT = 0.2 A
Figure 10-46. Output Voltage Ripple
Figure 10-47. Output Voltage Ripple
VOUT = 3.3 V
VIN = 5 V
PWM or PFM
CSS = 4.7 nF
TA = 25°C
IOUT = 2 A
VOUT = 1.8 V
VIN = 5 V
PWM or PFM
CSS = 4.7 nF
TA = 25°C
IOUT = 2 A
Figure 10-48. Start-Up Timing
Figure 10-49. Start-Up Timing
Copyright © 2020 Texas Instruments Incorporated
24
Submit Document Feedback
Product Folder Links: TPS628510 TPS628511 TPS628512
TPS628510, TPS628511, TPS628512
www.ti.com
SLUSDO4 – AUGUST 2020
VOUT = 1.2 V
VIN = 5 V
PWM or PFM
CSS = 4.7 nF
TA = 25°C
IOUT = 2 A
VOUT = 1.0 V
VIN = 5 V
PWM or PFM
CSS = 4.7 nF
TA = 25°C
IOUT = 2 A
Figure 10-50. Start-Up Timing
Figure 10-51. Start-Up Timing
VOUT = 0.6 V
VIN = 3.3 V
PWM or PFM
CSS = 4.7 nF
TA = 25°C
IOUT = 2 A
Figure 10-52. Start-Up Timing
10.3 System Examples
10.3.1 Fixed Output Voltage Versions
Versions with an internally fixed output voltage allow you to remove the external feedback voltage divider. This
not only allows you to reduce the total solution size but also provides higher accuracy as there is no additional
error caused by the external resistor divider. The FB pin needs to be tied to the output voltage directly as shown
in Figure 10-53. The application runs with an internally defined switching frequency of 2.25 MHz.
Copyright © 2020 Texas Instruments Incorporated
Submit Document Feedback
25
Product Folder Links: TPS628510 TPS628511 TPS628512
TPS628510, TPS628511, TPS628512
SLUSDO4 – AUGUST 2020
www.ti.com
L
V
IN
TPS62851x
VIN
0.47mH
2.7V - 6V
VOUT
SW
CIN
2*10 mF
0603
EN
FB
COUT
MODE/SYNC
2*10 mF
0603
R 3
SS/TR
PG
GND
Figure 10-53. Schematic for Fixed Output Voltage Versions
10.3.2 Voltage Tracking
The TPS62851x follows the voltage applied to the SS/TR pin. A voltage ramp on SS/TR to 0.6 V ramps the
output voltage according to the 0.6-V feedback voltage.
Tracking the 3.3 V of device 1, so that both rails reach their target voltage at the same time, requires a resistor
divider on SS/TR of device 2 equal to the output voltage divider of device 1. The output current of 2.5 µA on the
SS/TR pin causes an offset voltage on the resistor divider formed by R5 and R6. The equivalent resistance of
R5 // R6 must be kept below 15 kΩ. The current from SS/TR causes a slightly higher voltage across R6 than 0.6
V, which is desired because device 2 switches to its internal reference as soon as the voltage at SS/TR is higher
than 0.6 V.
In case both devices need to run in forced PWM mode, it is recommended to tie the MODE pin of device 2 to the
output voltage or the power good signal of device 1, the master device. The TPS6281x does have a duty cycle
limitation defined by the minimum on-time. For tracking down to low output voltages, device 2 cannot follow once
the minimum duty cycle is reached. Enabling PFM mode while tracking is in progress allows you to ramp down
the output voltage close to 0 V.
Copyright © 2020 Texas Instruments Incorporated
26
Submit Document Feedback
Product Folder Links: TPS628510 TPS628511 TPS628512
TPS628510, TPS628511, TPS628512
www.ti.com
SLUSDO4 – AUGUST 2020
Device 1 (master)
TPS62851x
V
L
IN
0.47 mH
2.7 V - 6 V
3.3 V
VIN
SW
10 pF
CIN
MODE/SYNC
2*10 mF
0603
FB
COUT
EN
EN
2*10 mF
0603
SS/TR
22 nF
PG
GND
Device 2 (slave)
TPS62851x
L
0.47 mH
1.8 V
VIN
SW
2*10 mF
CIN
0603
10 pF
EN
FB
R
5
COUT
2*10 mF
0603
MODE/SYNC
SS/TR
PG
GND
R
6
Figure 10-54. Schematic for Output Voltage Tracking
Figure 10-55. Scope Plot for Output Voltage Tracking
10.3.3 Synchronizing to an External Clock
The TPS62851x can be externally synchronized by applying an external clock on the MODE/SYNC pin. There is
no need for any additional circuitry as long as the input signal meets the requirements given in the electrical
specifications. The clock can be applied / removed during operation, allowing you to switch from an externally
defined fixed frequency to power-save mode or to internal fixed frequency operation.
Copyright © 2020 Texas Instruments Incorporated
Submit Document Feedback
27
Product Folder Links: TPS628510 TPS628511 TPS628512
TPS628510, TPS628511, TPS628512
SLUSDO4 – AUGUST 2020
www.ti.com
L
V
IN
TPS62851x
VIN
0.47 mH
VOUT
2.7 V - 6 V
SW
CIN
R1
2*10 mF
0603
CFF
EN
FB
COUT
MODE/SYNC
R2
R 3
2*10 mF
0603
SS/TR
fEXT
PG
GND
Figure 10-56. Schematic using External Synchronization
VIN = 5 V
RCF = 8.06 kΩ
fEXT = 2.5 MHz
IOUT = 0.1 A
VIN = 5 V
RCF = 8.06 kΩ
fEXT = 2.5 MHz
IOUT = 0.1 A
VOUT = 1.8 V
VOUT = 1.8 V
Figure 10-57. Switching from External
Figure 10-58. Switching from External
Syncronization to Power-Save Mode (PFM)
Synchronizaion to Internal Fixed Frequency
11 Power Supply Recommendations
The TPS62851x device family does not have special requirements for its input power supply. The output current
of the input power supply needs to be rated according to the supply voltage, output voltage, and output current
of the TPS62851x.
Copyright © 2020 Texas Instruments Incorporated
28
Submit Document Feedback
Product Folder Links: TPS628510 TPS628511 TPS628512
TPS628510, TPS628511, TPS628512
www.ti.com
SLUSDO4 – AUGUST 2020
12 Layout
12.1 Layout Guidelines
A proper layout is critical for the operation of a switched mode power supply, even more at high switching
frequencies. Therefore, the PCB layout of the TPS62851x demands careful attention to ensure operation and to
get the performance specified. A poor layout can lead to issues like poor regulation (both in Section 12.2 and
load), stability and accuracy weaknesses, increased EMI radiation, and noise sensitivity.
See Figure 12-1 for the recommended layout of the TPS62851x, which is designed for common external ground
connections. The input capacitor must be placed as close as possible between the VIN and GND pin.
Provide low inductive and resistive paths for loops with high di/dt. Therefore, paths conducting the switched load
current must be as short and wide as possible. Provide low capacitive paths (with respect to all other nodes) for
wires with high dv/dt. Therefore, the input and output capacitance must be placed as close as possible to the IC
pins and parallel wiring over long distances and narrow traces must be avoided. Loops which conduct an
alternating current should outline an area as small as possible, as this area is proportional to the energy
radiated.
Sensitive nodes like FB need to be connected with short wires and not nearby high dv/dt signals (for example,
SW). As they carry information about the output voltage, they must be connected as close as possible to the
actual output voltage (at the output capacitor). The capacitor on the SS/TR pin as well as the FB resistors, R1
and R2, must be kept close to the IC and be connected directly to the pin and the system ground plane.
The package uses the pins for power dissipation. Thermal vias on the VIN and GND pins help to spread the heat
into the pcb.
The recommended layout is implemented on the EVM and shown in the TPS62851xEVM-139 Evaluation Module
User's Guide.
12.2 Layout Example
COUT
GND
L
V
OUT
CIN
R2
U1
Css
V
IN
GND
Figure 12-1. Example Layout
Copyright © 2020 Texas Instruments Incorporated
Submit Document Feedback
29
Product Folder Links: TPS628510 TPS628511 TPS628512
TPS628510, TPS628511, TPS628512
SLUSDO4 – AUGUST 2020
www.ti.com
13 Device and Documentation Support
13.1 Device Support
13.1.1 Third-Party Products Disclaimer
TI'S PUBLICATION OF INFORMATION REGARDING THIRD-PARTY PRODUCTS OR SERVICES DOES NOT
CONSTITUTE AN ENDORSEMENT REGARDING THE SUITABILITY OF SUCH PRODUCTS OR SERVICES
OR A WARRANTY, REPRESENTATION OR ENDORSEMENT OF SUCH PRODUCTS OR SERVICES, EITHER
ALONE OR IN COMBINATION WITH ANY TI PRODUCT OR SERVICE.
13.2 Receiving Notification of Documentation Updates
To receive notification of documentation updates, navigate to the device product folder on ti.com. Click on
Subscribe to updates to register and receive a weekly digest of any product information that has changed. For
change details, review the revision history included in any revised document.
13.3 Support Resources
TI E2E™ support forums are an engineer's go-to source for fast, verified answers and design help — straight
from the experts. Search existing answers or ask your own question to get the quick design help you need.
Linked content is provided "AS IS" by the respective contributors. They do not constitute TI specifications and do
not necessarily reflect TI's views; see TI's Terms of Use.
13.4 Trademarks
TI E2E™ is a trademark of Texas Instruments.
All other trademarks are the property of their respective owners.
13.5 Electrostatic Discharge Caution
This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled
with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may
be more susceptible to damage because very small parametric changes could cause the device not to meet its published
specifications.
13.6 Glossary
TI Glossary
This glossary lists and explains terms, acronyms, and definitions.
Copyright © 2020 Texas Instruments Incorporated
30
Submit Document Feedback
Product Folder Links: TPS628510 TPS628511 TPS628512
TPS628510, TPS628511, TPS628512
www.ti.com
SLUSDO4 – AUGUST 2020
14 Mechanical, Packaging, and Orderable Information
The following pages include mechanical, packaging, and orderable information. This information is the most
current data available for the designated devices. This data is subject to change without notice and revision of
this document. For browser-based versions of this data sheet, refer to the left-hand navigation.
Copyright © 2020 Texas Instruments Incorporated
Submit Document Feedback
31
Product Folder Links: TPS628510 TPS628511 TPS628512
TPS628510, TPS628511, TPS628512
SLUSDO4 – AUGUST 2020
www.ti.com
Copyright © 2020 Texas Instruments Incorporated
32
Submit Document Feedback
Product Folder Links: TPS628510 TPS628511 TPS628512
TPS628510, TPS628511, TPS628512
www.ti.com
SLUSDO4 – AUGUST 2020
Copyright © 2020 Texas Instruments Incorporated
Submit Document Feedback
33
Product Folder Links: TPS628510 TPS628511 TPS628512
PACKAGE OPTION ADDENDUM
www.ti.com
30-Sep-2020
PACKAGING INFORMATION
Orderable Device
Status Package Type Package Pins Package
Eco Plan
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
Samples
Drawing
Qty
(1)
(2)
(3)
(4/5)
(6)
TPS628510DRLR
TPS628511DRLR
TPS628512DRLR
XPS628510DRLR
XPS628511DRLR
PREVIEW
PREVIEW
PREVIEW
PREVIEW
ACTIVE
SOT-5X3
SOT-5X3
SOT-5X3
SOT-5X3
SOT-5X3
DRL
DRL
DRL
DRL
DRL
8
8
8
8
8
4000
4000
4000
4000
4000
TBD
TBD
TBD
TBD
TBD
Call TI
Call TI
Call TI
Call TI
Call TI
Call TI
Call TI
Call TI
Call TI
Call TI
-40 to 150
-40 to 150
-40 to 150
-40 to 150
-40 to 150
XPS628512DRLR
PREVIEW
SOT-5X3
DRL
8
4000
TBD
Call TI
Call TI
-40 to 150
(1) The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of <=1000ppm threshold. Antimony trioxide based
flame retardants must also meet the <=1000ppm threshold requirement.
(3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.
(4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device.
(5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation
of the previous line and the two combined represent the entire Device Marking for that device.
(6)
Lead finish/Ball material - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead finish/Ball material values may wrap to two
lines if the finish value exceeds the maximum column width.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information
provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and
Addendum-Page 1
PACKAGE OPTION ADDENDUM
www.ti.com
30-Sep-2020
continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.
TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.
Addendum-Page 2
IMPORTANT NOTICE AND DISCLAIMER
TI PROVIDES TECHNICAL AND RELIABILITY DATA (INCLUDING DATASHEETS), DESIGN RESOURCES (INCLUDING REFERENCE
DESIGNS), APPLICATION OR OTHER DESIGN ADVICE, WEB TOOLS, SAFETY INFORMATION, AND OTHER RESOURCES “AS IS”
AND WITH ALL FAULTS, AND DISCLAIMS ALL WARRANTIES, EXPRESS AND IMPLIED, INCLUDING WITHOUT LIMITATION ANY
IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT OF THIRD
PARTY INTELLECTUAL PROPERTY RIGHTS.
These resources are intended for skilled developers designing with TI products. You are solely responsible for (1) selecting the appropriate
TI products for your application, (2) designing, validating and testing your application, and (3) ensuring your application meets applicable
standards, and any other safety, security, or other requirements. These resources are subject to change without notice. TI grants you
permission to use these resources only for development of an application that uses the TI products described in the resource. Other
reproduction and display of these resources is prohibited. No license is granted to any other TI intellectual property right or to any third
party intellectual property right. TI disclaims responsibility for, and you will fully indemnify TI and its representatives against, any claims,
damages, costs, losses, and liabilities arising out of your use of these resources.
TI’s products are provided subject to TI’s Terms of Sale (www.ti.com/legal/termsofsale.html) or other applicable terms available either on
ti.com or provided in conjunction with such TI products. TI’s provision of these resources does not expand or otherwise alter TI’s applicable
warranties or warranty disclaimers for TI products.
Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265
Copyright © 2020, Texas Instruments Incorporated
相关型号：
TPS628511DRLR
TPS62851x 2.7-V to 6-V, 0.5-A / 1-A / 2-A Step-Down Converter in SOT583 PackageWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
TI
TPS628512
TPS62851x 2.7-V to 6-V, 0.5-A / 1-A / 2-A Step-Down Converter in SOT583 PackageWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
TI
TPS628512DRLR
TPS62851x 2.7-V to 6-V, 0.5-A / 1-A / 2-A Step-Down Converter in SOT583 PackageWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
TI
TPS628513
采用 SOT-583 封装的 2.7V 至 6V、3A 固定频率降压转换器Warning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
TI
TPS628513DRLR
采用 SOT-583 封装的 2.7V 至 6V、3A 固定频率降压转换器 | DRL | 8 | -40 to 150Warning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
TI
TPS62851X
TPS62851x 2.7-V to 6-V, 0.5-A / 1-A / 2-A Step-Down Converter in SOT583 PackageWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
TI
TPS62860
1.8-V to 5.5-V Input, 0.6-/1-A Synchronous Step-Down Converter with I2C/VSEL InterfaceWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
TI
TPS628600
1.8-V to 5.5-V Input, 0.6-/1-A Synchronous Step-Down Converter with I2C/VSEL InterfaceWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
TI
TPS628600YCHR
1.8-V to 5.5-V Input, 0.6-/1-A Synchronous Step-Down Converter with I2C/VSEL InterfaceWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
TI
TPS628601YCHR
1.8-V to 5.5-V Input, 0.6-/1-A Synchronous Step-Down Converter with I2C/VSEL InterfaceWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
TI
TPS62861
具有 I2C/VSEL 接口的 1.75V 至 5.5V 输入、1A 超低 IQ 降压转换器Warning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
TI
TPS628610YCHR
1.75-V to 5.5-V, 1-A ultra-low IQ step-down converter with I2C/VSEL interface | YCH | 8 | -40 to 125Warning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
TI
©2020 ICPDF网 联系我们和版权申明