ADM7154ACPZ-1.8-R7 [ADI]
600 mA, Ultralow Noise, High PSRR, RF Linear Regulator;型号: | ADM7154ACPZ-1.8-R7 |
厂家: | ADI |
描述: | 600 mA, Ultralow Noise, High PSRR, RF Linear Regulator 光电二极管 输出元件 调节器 |
文件: | 总24页 (文件大小:812K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
600 mA, Ultralow Noise,
High PSRR, RF Linear Regulator
ADM7154
Data Sheet
FEATURES
TYPICAL APPLICATION CIRCUIT
Input voltage range: 2.3 V to 5.5 V
Maximum load current: 600 mA
Low noise
0.9 µV rms total integrated noise from 100 Hz to 100 kHz
1.6 µV rms total integrated noise from 10 Hz to 100 kHz
Noise spectral density: 1.5 nV/√Hz from 10 kHz to 1 MHz
PSRR of 90 dB from 200 Hz to 200 kHz; 58 dB at 1 MHz,
ADM7154
V
= 3.8V
V
= 3.3V
OUT
IN
VIN
VOUT
C
C
OUT
10µF
IN
10µF
ON
EN
REF
C
REF
OFF
1µF
BYP REF_SENSE
C
BYP
1µF
VREG
GND
C
REG
V
OUT = 3.3 V, VIN = 3.8 V
10µF
Dropout voltage: 120 mV typical at VOUT = 3.3 V, IOUT = 600 mA
Initial accuracy: 0.5%
Accuracy over line, load, and temperature: −2.0% (minimum),
+1.5% (maximum), from −40°C to +85°C
Quiescent current, IGND = 4 mA at no load
Low shutdown current: 0.2 μA
Stable with a 10 µF ceramic output capacitor
Adjustable and fixed output voltage options: 1.2 V, 1.8 V, 2.5 V,
2.8 V, 3.0 V, 3.3 V (16 standard voltages between 1.2 V and
3.3 V available)
8-lead LFCSP and 8-lead SOIC packages
Precision enable
Figure 1. Regulated 3.3 V Output from 3.8 V Input
10k
NOISE FLOOR
1.0µF
3.3µF
10µF
1k
100
10
33µF
100µF
330µF
1000µF
Supported by ADIsimPower tool
1
APPLICATIONS
0.1
0.1
Regulation to noise sensitive applications: PLLs, VCOs, and
PLLs with integrated VCOs
1
10
100
1k
10k
100k
1M
FREQUENCY (Hz)
Communications and infrastructure
Backhaul and microwave links
Figure 2. Noise Spectral Density for Different Values of CBYP
GENERAL DESCRIPTION
The ADM7154 is a linear regulator that operates from 2.3 V to
5.5 V and provides up to 600 mA of load current. Using an
advanced proprietary architecture, it provides high power
supply rejection and ultralow noise, achieving excellent line and
load transient response with only a 10 µF ceramic output capacitor.
The ADM7154 is available in 8-lead, 3 mm × 3 mm LFCSP and
8-lead SOIC packages, making it not only a very compact
solution, but also providing excellent thermal performance for
applications requiring up to 600 mA of load current in a small,
low profile footprint.
There are 16 standard output voltages for the ADM7154. The
following voltages are available in stock: 1.2 V, 1.8 V, 2.5 V, 2.8 V,
3.0 V, and 3.3 V. Additional voltages are available by special
order: 1.3 V, 1.5 V, 1.6 V, 2.0 V, 2.2 V, 2.6 V, 2.7 V, 2.9 V, 3.1 V,
and 3.2 V.
Table 1. Related Devices
Input
Voltage
Output
Fixed/
Model
Current Adj1
Package
ADM7150ACP 4.5 V to 16 V
ADM7150ARD 4.5 V to 16 V
ADM7151ACP 4.5 V to 16 V
ADM7151ARD 4.5 V to 16 V
ADM7155ACP 2.3 V to 5.5 V 600 mA
ADM7155ARD 2.3 V to 5.5 V 600 mA
800 mA
800 mA
800 mA
800 mA
Fixed
Fixed
Adj
Adj
Adj
8-Lead LFCSP
8-Lead SOIC
8-Lead LFCSP
8-Lead SOIC
8-Lead LFCSP
8-Lead SOIC
The ADM7154 regulator typical output noise is 0.9 μV rms from
100 Hz to 100 kHz for fixed output voltage options and
1.5 nV/√Hz for noise spectral density from 10 kHz to 1 MHz.
Adj
1 Adj means adjustable.
Rev. B
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ADM7154* PRODUCT PAGE QUICK LINKS
Last Content Update: 11/29/2017
COMPARABLE PARTS
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REFERENCE MATERIALS
Solutions Bulletins & Brochures
• Ultralow Noise, High Rejection Low Dropout Regulators
EVALUATION KITS
• AD9375 Small Cell Radio Reference Design
DESIGN RESOURCES
• ADM7154 Material Declaration
• PCN-PDN Information
• ADA4961 & AD9680 Analog Signal Chain Evaluation and
AD9528 Converter Synchronization
• ADM7154 Evaluation Board
• Quality And Reliability
• Symbols and Footprints
• TX/RX channels, Frequency conversion from 1 100 MHz
up to 400 MHz
DISCUSSIONS
View all ADM7154 EngineerZone Discussions.
DOCUMENTATION
Data Sheet
• ADM7154: 600 mA, Ultralow Noise, High PSRR, RF Linear
Regulator Data Sheet
SAMPLE AND BUY
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User Guides
• UG-696: Evaluating the ADM7154 and ADM7155 Linear
Regulators
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number.
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ADM7154
Data Sheet
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications Information .............................................................. 15
ADIsimPower Design Tool ....................................................... 15
Capacitor Selection .................................................................... 15
Undervoltage Lockout (UVLO) ............................................... 16
Programmable Precision Enable .............................................. 17
Start-Up Time ............................................................................. 17
REF, BYP, and VREG Pins......................................................... 18
Current-Limit and Thermal Overload Protection................. 18
Thermal Considerations............................................................ 18
PCB Layout Considerations.......................................................... 21
Outline Dimensions ....................................................................... 22
Ordering Guide .......................................................................... 23
Applications....................................................................................... 1
Typical Application Circuit ............................................................. 1
General Description......................................................................... 1
Revision History ............................................................................... 2
Specifications..................................................................................... 3
Absolute Maximum Ratings............................................................ 5
Thermal Data ................................................................................ 5
Thermal Resistance ...................................................................... 5
ESD Caution.................................................................................. 5
Pin Configurations and Function Descriptions ........................... 6
Typical Performance Characteristics ............................................. 7
Theory of Operation ...................................................................... 14
REVISION HISTORY
8/2016—Rev. A to Rev. B
Changes to Programmable Precision Enable Section and
Figure 52 .......................................................................................... 17
12/2014—Rev. 0 to Rev. A
Changes to Figure 35 to Figure 40................................................ 12
Changes to Figure 44...................................................................... 15
10/2014—Revision 0: Initial Version
Rev. B | Page 2 of 23
Data Sheet
ADM7154
SPECIFICATIONS
VIN = VOUT + 0.5 V or 2.3 V, whichever is greater; EN = VIN; ILOAD = 10 mA; CIN = COUT = CREG = 10 µF; CREF = CBYP = 1 µF; TA = 25°C for
typical specifications; TJ = −40°C to +125°C for minimum/maximum specifications, unless otherwise noted.
Table 2.
Parameter
Symbol
VIN
Test Conditions/Comments
Min
Typ Max
Unit
V
INPUT VOLTAGE RANGE
LOAD CURRENT
2.3
5.5
ILOAD
600
mA
mA
mA
µA
OPERATING SUPPLY CURRENT
IGND
ILOAD = 0 µA
ILOAD = 600 mA
EN = GND
4.0
6.5
0.2
7.0
10
2
SHUTDOWN CURRENT
NOISE
IIN_SD
Output Noise
OUTNOISE
10 Hz to 100 kHz, VOUT = 1.2 V to 3.3 V
100 Hz to 100 kHz, VOUT = 1.2 V to 3.3 V
10 kHz to 1 MHz, VOUT = 1.2 V to 3.3 V
200 Hz to 200 kHz, VIN = 3.8 V, VOUT = 3.3 V,
1.6
0.9
1.5
90
µV rms
µV rms
nV/√Hz
dB
Noise Spectral Density
OUTNSD
PSRR
POWER SUPPLY REJECTION RATIO
I
LOAD = 400 mA
1 MHz, VIN = 3.8 V, VOUT = 3.3 V, ILOAD = 400 mA
200 Hz to 200 kHz, VIN = 2.3 V, VOUT = 1.8 V,
58
90
dB
dB
I
LOAD = 400 mA
1 MHz, VIN = 2.3 V, VOUT = 1.8 V, ILOAD = 400 mA
VOUT = VREF
ILOAD = 10 mA, TJ = +25°C
1 mA < ILOAD < 600 mA, TJ = −40°C to +85°C
1 mA < ILOAD < 600 mA
63
dB
OUTPUT VOLTAGE ACCURACY
Initial Accuracy
VOUT
−0.5
−2.0
−2.0
+0.5
+1.5
+2.0
%
%
%
REGULATION
Line
∆VOUT/∆VIN
VIN = VOUT + 0.5 V or 2.3 V, whichever is greater,
to 5.5 V
IOUT = 1 mA to 600 mA
−0.02
+0.02 %/V
Load1
∆VOUT/∆IOUT
ILIMIT
0.3
1.6
%/A
CURRENT-LIMIT THRESHOLD2
VREF
VOUT
22
960
80
mA
mA
mV
mV
700
1200
130
210
DROPOUT VOLTAGE 3
VDROPOUT
IOUT = 400 mA, VOUT = 3.3 V
IOUT = 600 mA, VOUT = 3.3 V
120
PULL-DOWN RESISTANCE
VOUT
REG
REF
BYP
VOUT_PULL
VREG_PULL
VREF_PULL
VBYP_PULL
EN = 0 V, VOUT = 1 V, VIN = 5.5 V
EN = 0 V, VREG = 1 V, VIN = 5.5 V
EN = 0 V, VREF = 1 V, VIN = 5.5 V
EN = 0 V, VBYP = 1 V, VIN = 5.5 V
550
33
620
400
Ω
kΩ
Ω
Ω
START-UP TIME4
VOUT
VREG
VREF
tSTARTUP
tREG_STARTUP
tREF_STARTUP
VOUT = 3.3 V
VOUT = 3.3 V
VOUT = 3.3 V
1.2
0.55
0.44
ms
ms
ms
THERMAL SHUTDOWN
Threshold
Hysteresis
TSSD
TSSD_HYS
TJ rising
150
15
°C
°C
UNDERVOLTAGE THRESHOLDS
Input Voltage
Rising
Falling
Hysteresis
UVLORISE
UVLOFALL
UVLOHYS
2.29
V
V
mV
1.95
200
Rev. B | Page 3 of 23
ADM7154
Data Sheet
Parameter
Symbol
Test Conditions/Comments
Min
Typ Max
Unit
VREG THRESHOLDS5
Rising
Falling
Hysteresis
VREG_UVLORISE
VREG_UVLOFALL
VREG_UVLOHYS
1.94
V
V
mV
1.60
185
PRECISION EN INPUT
Logic High
Logic Low
Logic Hysteresis
Leakage Current
2.3 V ≤ VIN ≤ 5.5 V
EN = VIN or GND
ENHIGH
ENLOW
ENHYS
IEN_LKG
1.13
1.05
1.22 1.31
1.13 1.22
90
V
V
mV
µA
0.01
1
1 Based on an endpoint calculation using 1 mA and 600 mA loads.
2 Current-limit threshold is defined as the current at which the output voltage drops to 90% of the specified typical value. For example, the current limit for a 3.0 V
output voltage is defined as the current that causes the output voltage to drop to 90% of 3.0 V, or 2.7 V.
3 Dropout voltage is defined as the input-to-output voltage differential when the input voltage is set to the nominal output voltage. Dropout applies only for output
voltages above 2.3 V.
4 Start-up time is defined as the time between the rising edge of VEN to VOUT, VREG, or VREF being at 90% of the nominal value.
5 The output voltage is disabled until the VREG UVLO rise threshold is crossed. The VREG output is disabled until the input voltage UVLO rising threshold is crossed.
Table 3. Input and Output Capacitors, Recommended Specifications
Parameter
MINIMUM CAPACITANCE
Input1
Regulator1
Output1
Symbol
Test Conditions/Comments
Min
Typ
Max
Unit
CIN
TA = −40°C to +125°C
TA = −40°C to +125°C
TA = −40°C to +125°C
TA = −40°C to +125°C
TA = −40°C to +125°C
7.0
7.0
7.0
0.1
0.7
µF
µF
µF
µF
µF
CREG
COUT
CBYP
CREF
Bypass
Reference
CAPACITOR ESR
CREG, COUT, CIN, CREF
CBYP
RESR
RESR
TA = −40°C to +125°C
TA = −40°C to +125°C
0.001
0.001
0.2
2.0
Ω
Ω
1 The minimum input, regulator, and output capacitances must be greater than 7.0 μF over the full range of operating conditions. The full range of operating conditions
in the application must be considered during device selection to ensure that the minimum capacitance specification is met. X7R and X5R type capacitors are
recommended; Y5V and Z5U capacitors are not recommended for use with any LDO.
Rev. B | Page 4 of 23
Data Sheet
ADM7154
ABSOLUTE MAXIMUM RATINGS
Junction-to-ambient thermal resistance (θJA) of the package is
based on modeling and calculation using a 4-layer PCB. The
junction-to-ambient thermal resistance is highly dependent on
the application and PCB layout. In applications where high
maximum power dissipation exists, close attention to thermal
PCB design is required. The value of θJA can vary, depending on
PCB material, layout, and environmental conditions. The
specified values of θJA are based on a 4-layer, 4 in. × 3 in. circuit
board. See JESD51-7 and JESD51-9 for detailed information on
the board construction.
Table 4.
Parameter
VIN to GND
VREG to GND
Rating
−0.3 V to +7 V
−0.3 V to VIN, or +4 V
(whichever is less)
VOUT to GND
−0.3 V to VREG, or +4 V
(whichever is less)
BYP to VOUT
EN to GND
BYP to GND
0.3 V
−0.3 V to +7 V
−0.3 V to VREG, or +4 V
(whichever is less)
ΨJB is the junction-to-board thermal characterization parameter
REF to GND
−0.3 V to VREG, or +4 V
(whichever is less)
with units of °C/W. ΨJB of the package is based on modeling and
calculation using a 4-layer PCB. JESD51-12, Guidelines for
Reporting and Using Electronic Package Thermal Information,
states that thermal characterization parameters are not the same
as thermal resistances. ΨJB measures the component power
flowing through multiple thermal paths rather than a single
path as in thermal resistance, θJB. Therefore, ΨJB thermal paths
include convection from the top of the package as well as
radiation from the package, factors that make ΨJB more useful
in real-world applications. Maximum junction temperature (TJ)
is calculated from the PCB temperature (TB) and power
dissipation (PD) using the formula
REF_SENSE to GND
Storage Temperature Range
Junction Temperature
−0.3 V to +4 V
−65°C to +150°C
150°C
Operating Ambient Temperature
Range
−40°C to +125°C
Soldering Conditions
JEDEC J-STD-020
Stresses at or above those listed under Absolute Maximum
Ratings may cause permanent damage to the product. This is a
stress rating only; functional operation of the product at these
or any other conditions above those indicated in the operational
section of this specification is not implied. Operation beyond
the maximum operating conditions for extended periods may
affect product reliability.
TJ = TB + (PD × ΨJB)
See JESD51-8 and JESD51-12 for more detailed information
about ΨJB.
THERMAL DATA
THERMAL RESISTANCE
Absolute maximum ratings apply individually only, not in
combination. The ADM7154 can be damaged when the
junction temperature limits are exceeded. Monitoring ambient
temperature does not guarantee that TJ is within the specified
temperature limits. In applications with high power dissipation
and poor thermal resistance, the maximum ambient temper-
ature may need to be derated.
θJA, θJC, and ΨJB are specified for the worst case conditions, that
is, a device soldered in a circuit board for surface-mount
packages.
Table 5. Thermal Resistance
Package Type
8-Lead LFCSP
8-Lead SOIC
θJA
θJC
ΨJB
Unit
°C/W
°C/W
36.7
36.9
23.5
27.1
13.3
18.6
In applications with moderate power dissipation and low
printed circuit board (PCB) thermal resistance, the maximum
ambient temperature can exceed the maximum limit provided
that the junction temperature is within specification limits. The
junction temperature (TJ) of the device is dependent on the
ambient temperature (TA), the power dissipation of the device
(PD), and the junction-to-ambient thermal resistance of the
package (θJA).
ESD CAUTION
Maximum junction temperature (TJ) is calculated from the
ambient temperature (TA) and power dissipation (PD) using the
following formula:
TJ = TA + (PD × θJA)
Rev. B | Page 5 of 23
ADM7154
Data Sheet
PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS
VREG
VOUT
BYP
1
2
3
4
8
7
6
5
VIN
EN
VREG 1
VOUT 2
BYP 3
8
VIN
ADM7154
7
EN
TOP VIEW
ADM7154
REF
(Not to Scale)
TOP VIEW
6 REF
GND
REF_SENSE
(Not to Scale)
5 REF_SENSE
GND 4
NOTES
1. THE EXPOSED PAD IS LOCATED ON THE BOTTOM OF
THE PACKAGE. THE EXPOSED PAD ENHANCES
THERMAL PERFORMANCE, AND IT IS ELECTRICALLY
CONNECTED TO GND INSIDE THE PACKAGE. CONNECT
THE EP TO THE GROUND PLANE ON THE BOARD TO
ENSURE PROPER OPERATION.
NOTES
1. THE EXPOSED PAD IS LOCATED ON THE BOTTOM OF
THE PACKAGE. THE EXPOSED PAD ENHANCES
THERMAL PERFORMANCE, AND IT IS ELECTRICALLY
CONNECTED TO GND INSIDE THE PACKAGE. CONNECT
THE EP TO THE GROUND PLANE ON THE BOARD TO
ENSURE PROPER OPERATION.
Figure 3. 8-Lead LFCSP Pin Configuration
Figure 4. 8-Lead SOIC Pin Configuration
Table 6. Pin Function Descriptions
Pin No.
Mnemonic
Description
1
VREG
Regulated Input Supply Voltage to LDO Amplifier. Bypass VREG to GND with a 10 µF or greater
capacitor.
2
3
VOUT
BYP
Regulated Output Voltage. Bypass VOUT to GND with a 10 µF or greater capacitor.
Low Noise Bypass Capacitor. Connect a 1 µF capacitor from the BYP pin to GND to reduce noise. Do not
connect a load to ground.
4
5
6
GND
REF_SENSE
REF
Ground Connection.
Reference Sense. Connect Pin 5 to the REF pin. Do not connect Pin 5 to VOUT or GND.
Low Noise Reference Voltage Output. Bypass REF to GND with a 1 µF capacitor. Short REF_SENSE to REF
for fixed output voltages. Do not connect a load to ground.
7
8
EN
Enable. Drive EN high to turn on the regulator; drive EN low to turn off the regulator. For automatic
startup, connect EN to VIN.
Regulator Input Supply Voltage. Bypass VIN to GND with a 10 µF or greater capacitor.
Exposed Pad. The exposed pad is located on the bottom of the package. The exposed pad enhances
thermal performance, and it is electrically connected to GND inside the package. Connect the EP to the
ground plane on the board to ensure proper operation.
VIN
EP
Rev. B | Page 6 of 23
Data Sheet
ADM7154
TYPICAL PERFORMANCE CHARACTERISTICS
VIN = VOUT + 0.5 V, or VIN = 2.3 V, whichever is greater; VEN = VIN; IOUT = 10 mA; CIN = COUT = CREG = 10 µF; CREF = CBYP = 1 µF; TA = 25°C,
unless otherwise noted.
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
3.33
3.32
3.31
3.30
3.29
3.28
3.27
V
V
V
V
V
V
= 2.3V
= 2.4V
= 2.6V
= 3.0V
= 4.0V
= 5.5V
IN
IN
IN
IN
IN
IN
I
I
I
I
I
I
= 1mA
LOAD
LOAD
LOAD
LOAD
LOAD
LOAD
= 10mA
= 100mA
= 200mA
= 400mA
= 600mA
–50
–25
0
25
50
75
100
125
3.5
4.0
4.5
(V)
5.0
5.5
TEMPERATURE (°C)
V
IN
Figure 5. Shutdown Current vs. Temperature at
Various Input Voltages, VOUT = 1.8 V
Figure 8. Output Voltage (VOUT) vs. Input Voltage (VIN) at Various Loads,
VOUT = 3.3 V
3.33
3.32
3.31
3.30
3.29
3.28
3.27
10
9
8
7
6
5
4
3
2
1
0
I
I
I
I
I
I
= 1mA
LOAD
LOAD
LOAD
LOAD
LOAD
LOAD
I
I
I
I
I
I
= 1mA
LOAD
LOAD
LOAD
LOAD
LOAD
LOAD
= 10mA
= 100mA
= 200mA
= 400mA
= 600mA
= 10mA
= 100mA
= 200mA
= 400mA
= 600mA
–40
–5
25
85
125
–40
–5
25
85
125
JUNCTION TEMPERATURE (°C)
JUNCTION TEMPERATURE (°C)
Figure 6. Output Voltage (VOUT) vs. Junction Temperature at Various Loads,
OUT = 3.3 V
Figure 9. Ground Current vs. Junction Temperature (TJ) at Various Loads,
OUT = 3.3 V
V
V
3.33
3.32
3.31
3.30
3.29
3.28
3.27
10
9
8
7
6
5
4
3
2
1
0
1
10
100
1000
1
10
100
1000
I
(mA)
I
(mA)
LOAD
LOAD
Figure 7. Output Voltage (VOUT) vs. Load Current (ILOAD), VOUT = 3.3 V
Figure 10. Ground Current vs. Load Current (ILOAD), VOUT = 3.3 V
Rev. B | Page 7 of 23
ADM7154
Data Sheet
10
9
10
9
8
7
6
5
4
3
2
1
0
8
7
6
5
4
3
I
I
I
I
I
I
= 5mA
= 10mA
= 100mA
= 200mA
= 400mA
= 600mA
I
= 1mA
LOAD
LOAD
I
I
I
I
I
= 10mA
= 100mA
= 200mA
= 400mA
= 600mA
LOAD
LOAD
LOAD
LOAD
LOAD
LOAD
LOAD
LOAD
LOAD
LOAD
2
1
0
3.5
4.0
4.5
(V)
5.0
5.5
3.1
3.2
3.3
3.4
3.5
(V)
3.6
3.7
3.8
V
V
IN
IN
Figure 11. Ground Current vs. Input Voltage (VIN) at Various Loads,
VOUT = 3.3 V
Figure 14. Ground Current vs. Input Voltage (VIN) in Dropout, VOUT = 3.3 V
160
140
120
100
80
1.820
1.815
1.810
1.805
1.800
1.795
60
I
I
I
I
I
I
= 1mA
LOAD
LOAD
LOAD
LOAD
LOAD
LOAD
40
1.790
1.785
1.780
= 10mA
= 100mA
= 200mA
= 400mA
= 600mA
20
0
1
10
100
1000
–40
–5
25
85
125
I
(mA)
JUNCTION TEMPERATURE (°C)
LOAD
Figure 12. Dropout Voltage vs. Load Current (ILOAD), VOUT = 3.3 V
Figure 15. Output Voltage (VOUT) vs. Junction Temperature (TJ) at Various
Loads, VOUT = 1.8 V
3.40
3.35
3.30
3.25
3.20
3.15
1.820
1.815
1.810
1.805
1.800
1.795
1.790
1.785
1.780
I
I
I
I
I
I
= 5mA
LOAD
LOAD
LOAD
LOAD
LOAD
LOAD
3.10
3.05
3.00
= 10mA
= 100mA
= 200mA
= 400mA
= 600mA
3.1
3.2
3.3
3.4
3.5
(V)
3.6
3.7
3.8
1
10
100
1000
V
I
(mA)
LOAD
IN
Figure 13. Output Voltage (VOUT) vs. Input Voltage (VIN) in Dropout,
OUT = 3.3 V
Figure 16. Output Voltage (VOUT) vs. Load Current (ILOAD), VOUT = 1.8 V
V
Rev. B | Page 8 of 23
Data Sheet
ADM7154
1.820
1.815
1.810
1.805
1.800
1.795
1.790
1.785
1.780
8
7
6
5
4
3
2
1
0
I
I
I
I
I
I
= 1mA
LOAD
LOAD
LOAD
LOAD
LOAD
LOAD
= 10mA
= 100mA
= 200mA
= 400mA
= 600mA
I
I
I
I
I
I
= 1mA
LOAD
LOAD
LOAD
LOAD
LOAD
LOAD
= 10mA
= 100mA
= 200mA
= 400mA
= 600mA
2.0
2.5
3.0
3.5
4.0
(V)
4.5
5.0
5.5
2.0
2.5
3.0
3.5
4.0
(V)
4.5
5.0
5.5
V
V
IN
IN
Figure 17. Output Voltage (VOUT) vs. Input Voltage (VIN) at Various Loads,
Figure 20. Ground Current vs. Input Voltage (VIN) at Different Loads,
OUT = 1.8 V
VOUT = 1.8 V
V
10
9
8
7
6
5
4
3
2
1
0
0
I
I
I
I
= 100mA
= 200mA
= 400mA
= 600mA
LOAD
LOAD
LOAD
LOAD
–20
–40
–60
–80
–100
–120
–140
I
I
I
I
I
I
= 1mA
LOAD
LOAD
LOAD
LOAD
LOAD
LOAD
= 10mA
= 100mA
= 200mA
= 400mA
= 600mA
–40
–5
25
85
125
1
10
100
1k
10k
100k
1M
10M
JUNCTION TEMPERATURE (°C)
FREQUENCY (Hz)
Figure 18. Ground Current vs. Junction Temperature (TJ) at Various Loads,
OUT = 1.8 V
Figure 21. Power Supply Rejection Ratio (PSRR) vs. Frequency at Various
Loads, VOUT = 3.3 V, VIN = 4.1 V
V
7
6
5
4
3
2
1
0
0
–20
–40
–60
–80
800mV
600mV
500mV
400mV
300mV
250mV
200mV
150mV
–100
–120
–140
1
10
100
1k
10k
100k
1M
10M
1
10
100
1000
FREQUENCY (Hz)
I
(mA)
LOAD
Figure 19. Ground Current vs. Load Current (ILOAD), VOUT = 1.8 V
Figure 22. Power Supply Rejection Ratio (PSRR) vs. Frequency at Various
Headroom Voltages, VOUT = 3.3 V, 400 mA Load
Rev. B | Page 9 of 23
ADM7154
Data Sheet
0
–20
–40
–60
–80
0
–20
10Hz
100Hz
1kHz
100kHz
1MHz
10MHz
10kHz
–40
–60
–80
10Hz
–100
–120
–140
–100
–120
–140
100Hz
1kHz
10kHz
100kHz
1MHz
10MHz
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.25
0.35
0.45
0.55
0.65
0.75
HEADROOM (V)
HEADROOM (V)
Figure 23. Power Supply Rejection Ratio (PSRR) vs. Headroom Voltage at
Different Frequencies, VOUT = 3.3 V, 400 mA Load
Figure 26. Power Supply Rejection Ratio (PSRR) vs. Headroom Voltage,
Different Frequencies, VOUT = 1.8 V, 400 mA Load
0
0
I
I
I
I
= 100mA
= 200mA
= 400mA
= 600mA
1µF
10µF
100µF
LOAD
LOAD
LOAD
LOAD
–20
–40
–20
–40
1000µF
–60
–60
–80
–80
–100
–120
–140
–100
–120
–140
1
10
100
1k
10k
100k
1M
10M
1
10
100
1k
10k
100k
1M
10M
FREQUENCY (Hz)
FREQUENCY (Hz)
Figure 27. Power Supply Rejection Ratio (PSRR) vs. Frequency, Different CBYP
,
Figure 24. Power Supply Rejection Ratio (PSRR) vs. Frequency at Various
Loads, VOUT = 1.8 V, VIN = 2.6 V
VOUT = 3.3 V, 400 mA Load, 500 mV Headroom
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
0
–20
–40
–60
–80
10Hz TO 100kHz
100Hz TO 100kHz
–100
800mV
600mV
500mV
400mV
300mV
–120
250mV
–140
10
100
1000
1
10
100
1k
10k
100k
1M 10M
LOAD CURRENT (mA)
FREQUENCY (Hz)
Figure 28. RMS Output Noise vs. Load Current
Figure 25. Power Supply Rejection Ratio (PSRR) vs. Frequency at Various
Headroom Voltages, VOUT = 1.8 V, 400 mA Load
Rev. B | Page 10 of 23
Data Sheet
ADM7154
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
10k
1k
10Hz TO 100kHz
100Hz TO 100kHz
100
10
1
0
0.1
1.0
1.5
2.0
2.5
3.0
3.5
10M
1M
0.1
1
10
100
1k
10k
100k
1M
10M
OUTPUT VOLTAGE (V)
FREQUENCY (Hz)
Figure 29. RMS Output Noise vs. Output Voltage
Figure 32. Output Noise Spectral Density, 0.1 Hz to 10 MHz, ILOAD = 100 mA
1k
100
10
10k
I
I
I
I
I
= 10mA
LOAD
LOAD
LOAD
LOAD
LOAD
= 100mA
= 200mA
= 400mA
= 600mA
1k
100
10
1
1
0.1
0.1
0.1
10
100
1k
10k
100k
1M
1
10
100
1k
10k
100k
1M
FREQUENCY (Hz)
FREQUENCY (Hz)
Figure 30. Output Noise Spectral Density,
10 Hz to 10 MHz, ILOAD = 100 mA
Figure 33. Output Noise Spectral Density at Various Loads,
0.1 Hz to 1 MHz
10k
1k
1k
100
10
I
I
I
I
I
= 10mA
LOAD
LOAD
LOAD
LOAD
LOAD
= 100mA
= 200mA
= 400mA
= 600mA
100
10
1
1
0.1
0.1
10
0.1
1
10
100
1k
10k
100k
100
1k
10k
100k
1M
10M
FREQUENCY (Hz)
FREQUENCY (Hz)
Figure 31. Output Noise Spectral Density,
0.1 Hz to 1 MHz, ILOAD = 10 mA
Figure 34. Output Noise Spectral Density at Various Loads,
10 Hz to 10 MHz
Rev. B | Page 11 of 23
ADM7154
Data Sheet
T
T
1
2
1
2
B
B
B
B
CH1 200mA Ω
CH2 5mV
M4.0µs
W
T 10.2%
A CH1
212mA
CH1 200mA Ω
CH2 5mV
M4µs A CH1
T 10.6%
532mA
W
W
W
Figure 35. Load Transient Response, ILOAD = 10 mA to 510 mA,
OUT = 3.3 V, VIN = 3.8 V, CH1 = IOUT, CH2 = VOUT
Figure 38. Load Transient Response, ILOAD = 100 mA to 600 mA,
OUT = 1.8 V, VIN = 2.3 V, CH1 = IOUT, CH2 = VOUT
V
V
T
T
1
2
2
1
B
B
B
B
CH1 200mA Ω
CH2 5mV
M4.0µs
W
T 10.2%
A CH1
212mA
CH1 1V
CH2 1mV
M400ns
T 10.4%
A CH1
4.38V
W
W
W
Figure 36. Load Transient Response, ILOAD = 100 mA to 600 mA,
OUT = 3.3 V, VIN = 3.8 V, CH1 = IOUT, CH2 = VOUT
Figure 39. Line Transient Response, 1 V Input Step, ILOAD = 600 mA,
OUT = 3.3 V, VIN = 3.9 V, CH1 = VIN, CH2 = VOUT
V
V
T
T
1
2
1
2
B
B
B
B
CH1 200mA Ω
CH2 5mV
M4.0µs
W
T 10.4%
A CH1
204mA
CH1 1V
CH2 1mV
M400ns
T 11.4%
A CH1
3.5V
W
W
W
Figure 37. Load Transient Response, ILOAD = 10 mA to 510 mA,
OUT = 1.8 V, VIN = 2.3 V, CH1 = IOUT, CH2 = VOUT
Figure 40. Line Transient Response, 1 V Input Step, ILOAD = 600 mA,
OUT = 1.8 V, VIN = 2.4 V, CH1 = VIN, CH2 = VOUT
V
V
Rev. B | Page 12 of 23
Data Sheet
ADM7154
3.5
ENABLE (V
)
EN
1.2V
1.8V
3.3V
3.0
2.5
2.0
1.5
1.0
0.5
0
0
1
2
3
4
5
6
7
8
9
10
TIME (ms)
Figure 41. VOUT Start-Up Time After VEN Rising, Different Output Voltages,
IN = 5 V
V
Rev. B | Page 13 of 23
ADM7154
Data Sheet
THEORY OF OPERATION
The ADM7154 is an ultralow noise, high power supply rejection
ratio (PSRR) linear regulator targeting radio frequency (RF)
applications. The input voltage range is 2.3 V to 5.5 V, and it can
deliver up to 600 mA of load current. Typical shutdown current
consumption is 0.2 µA at room temperature.
By heavily filtering the reference voltage, the ADM7154 is able
to achieve 1.5 nV/√Hz output typical from 10 kHz to 1 MHz.
Because the error amplifier is always in unity gain, the output
noise is independent of the output voltage.
To maintain very high PSRR over a wide frequency range, the
ADM7154 architecture uses an internal active ripple filter. This
stage isolates the low output noise LDO from noise on the VIN
pin. The result is that the PSRR of the ADM7154 is significantly
higher over a wider frequency range than any single stage LDO.
Optimized for use with 10 µF ceramic capacitors, the ADM7154
provides excellent transient performance.
ACTIVE
RIPPLE
FILTER
VIN
VOUT
CURRENT-LIMIT,
THERMAL
The ADM7154 uses the EN pin to enable and disable the VOUT
pin under normal operating conditions. When EN is high,
VOUT turns on, and when EN is low, VOUT turns off. For
automatic startup, tie EN to VIN.
VREG
BYP
PROTECT
GND
OTA
REFERENCE
VIN
7V
REF_SENSE
REF
VREG
SHUTDOWN
EN
4V
REF
Figure 42. Simplified Internal Block Diagram
REF_SENSE
BYP
4V
Internally, the ADM7154 consists of a reference, an error
amplifier, and a P-channel MOSFET pass transistor. Output
current is delivered via the PMOS pass device, which is
controlled by the error amplifier. The error amplifier compares
the reference voltage with the feedback voltage from the output
and amplifies the difference. If the feedback voltage is lower
than the reference voltage, the gate of the PMOS device is
pulled lower, allowing more current to pass and increasing the
output voltage. If the feedback voltage is higher than the
reference voltage, the gate of the PMOS device is pulled higher,
allowing less current to pass and decreasing the output voltage.
4V
VOUT
EN
7V
4V
4V
4V
4V
4V
7V
GND
Figure 43. Simplified ESD Protection Block Diagram
The ESD protection devices are shown in the block diagram as
Zener diodes (see Figure 43).
Rev. B | Page 14 of 23
Data Sheet
ADM7154
APPLICATIONS INFORMATION
Input and VREG Capacitor
ADIsimPOWER DESIGN TOOL
Connecting a 10 µF capacitor from VIN to GND reduces the
circuit sensitivity to PCB layout, especially when long input
traces or high source impedance are encountered.
The ADM7154 is supported by the ADIsimPower™ design tool
set. ADIsimPower is a collection of tools that produce complete
power designs optimized for a specific design goal. The tools
enable the user to generate a full schematic, bill of materials,
and calculate performance within minutes. ADIsimPower can
optimize designs for cost, area, efficiency, and device count,
taking into consideration the operating conditions and
limitations of the IC and all real external components. For more
information about, and to obtain ADIsimPower design tools,
visit www.analog.com/ADIsimPower.
To maintain the best possible stability and PSRR performance,
connect a 10 µF capacitor from VREG to GND. When more
than 10 µF of output capacitance is required, increase the input
and the VREG capacitors, CREG, to match it.
REF Capacitor
The REF capacitor, CREF, is necessary to stabilize the reference
amplifier. Connect at least a 1 µF capacitor between REF and GND.
CAPACITOR SELECTION
BYP Capacitor
Multilayer ceramic capacitors (MLCCs) combine small size, low
ESR, low ESL, and wide operating temperature range, making
them an ideal choice for bypass capacitors. They are not without
faults, however. Depending on the dielectric material, the
capacitance can vary dramatically with temperature, dc bias,
and ac signal level. Therefore, selecting the proper capacitor
results in the best circuit performance.
The BYP capacitor, CBYP, is necessary to filter the reference
buffer. A 1 µF capacitor is typically connected between BYP and
GND. Capacitors as small as 0.1 µF can be used; however, the
output noise voltage of the LDO increases as a result.
In addition, the BYP capacitor value can be increased to reduce
the noise below 1 kHz at the expense of increasing the start-up
time of the LDO. Very large values of CBYP significantly reduce
the noise below 10 Hz. Tantalum capacitors are recommended
for capacitors larger than approximately 33 µF because solid
tantalum capacitors are less prone to microphonic noise issues.
A 1 μF ceramic capacitor in parallel with the larger tantalum
capacitor is recommended to ensure good noise performance at
higher frequencies.
Output Capacitor
The ADM7154 is designed for operation with ceramic
capacitors but functions with most commonly used capacitors
when care is taken with regard to the effective series resistance
(ESR) value. The ESR of the output capacitor affects the stability
of the LDO control loop. A minimum of 10 µF capacitance with
an ESR of 0.2 Ω or less is recommended to ensure the stability
of the ADM7154. Output capacitance also affects transient
response to changes in load current. Using a larger value of
output capacitance improves the transient response of the
ADM7154 to large changes in load current. Figure 44 shows the
transient responses for an output capacitance value of 10 µF.
2.0
10Hz TO 100kHz
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
100Hz TO 100kHz
T
1
2
1
10
100
1000
C
(µF)
BYP
Figure 45. RMS Noise vs. CBYP
B
B
CH1 200mA
Ω
CH2 5mV
M4µs A CH1
10.2%
212mA
W
W
T
Figure 44. Output Transient Response, VOUT = 3.3 V, COUT = 10 µF,
CH1 = Load Current, CH2 = VOUT
Rev. B | Page 15 of 23
ADM7154
Data Sheet
10k
Use Equation 1 to determine the worst case capacitance
accounting for capacitor variation over temperature,
component tolerance, and voltage.
NOISE FLOOR
1.0µF
3.3µF
10µF
33µF
100µF
330µF
1000µF
1k
100
10
C
EFF = CBIAS × (1 − TEMPCO) × (1 − TOL)
where:
BIAS is the effective capacitance at the operating voltage.
(1)
C
TEMPCO is the worst case capacitor temperature coefficient.
TOL is the worst case component tolerance.
In this example, the worst case temperature coefficient
1
(TEMPCO) over −40°C to +85°C is assumed to be 15% for an
X5R dielectric. The tolerance of the capacitor (TOL) is assumed
to be 10%, and CBIAS is 9.72 µF at 5 V, as shown in Figure 47.
0.1
0.1
1
10
100
1k
10k
100k
1M
FREQUENCY (Hz)
Substituting these values in Equation 1 yields
Figure 46. Noise Spectral Density vs. Frequency at
Different Capacitances (CBYP
CEFF = 9.72 µF × (1 − 0.15) × (1 − 0.1) = 7.44 µF
)
Therefore, the capacitor chosen in this example meets the
minimum capacitance requirement of the LDO over
temperature and tolerance at the chosen output voltage.
Capacitor Properties
Any good quality ceramic capacitors can be used with the
ADM7154 if they meet the minimum capacitance and maxi-
mum ESR requirements. Ceramic capacitors are manufactured
with a variety of dielectrics, each with different behavior over
temperature and applied voltage. Capacitors must have a
dielectric adequate to ensure the minimum capacitance over
the necessary temperature range and dc bias conditions. X5R
or X7R dielectrics with a voltage rating of 6.3 V to 50 V
are recommended. However, Y5V and Z5U dielectrics are
not recommended because of their poor temperature and dc
bias characteristics.
To guarantee the performance of the ADM7154, it is imperative
that the effects of dc bias, temperature, and tolerances on the
behavior of the capacitors be evaluated for each application.
UNDERVOLTAGE LOCKOUT (UVLO)
The ADM7154 also incorporates an internal UVLO circuit to
disable the output voltage when the input voltage is less than the
minimum input voltage rating of the regulator. The upper and
lower thresholds are internally fixed with about 200 mV of
hysteresis.
Figure 47 depicts the capacitance vs. dc bias voltage of a 1206,
10 µF, 10 V, X5R capacitor. The voltage stability of a capacitor is
strongly influenced by the capacitor size and voltage rating. In
general, a capacitor in a larger package or higher voltage rating
exhibits better stability. The temperature variation of the X5R
dielectric is ~ 15% over the −40°C to +85°C temperature range
and is not a function of package or voltage rating.
12
2.5
+125°C
+25°C
–40°C
2.0
1.5
1.0
0.5
0
10
8
1.90
1.95
2.00
2.05
2.10
2.15
2.20
2.25
2.30
6
INPUT VOLTAGE (V)
Figure 48. Typical UVLO Behavior at Different Temperatures, VOUT = 3.3 V
4
Figure 48 shows the typical hysteresis of the UVLO function.
This hysteresis prevents on/off oscillations that can occur when
caused by noise on the input voltage as it passes through the
threshold points.
2
0
0
2
4
6
8
10
DC BIAS VOLTAGE (V)
Figure 47. Capacitance vs. DC Bias Voltage
Rev. B | Page 16 of 23
Data Sheet
ADM7154
The upper and lower thresholds are user programmable and can
be set higher than the nominal 1.22 V threshold by using two
resistors. The resistance values, REN1 and REN2, can be
determined from
PROGRAMMABLE PRECISION ENABLE
The ADM7154 uses the EN pin to enable and disable the
VOUT pin under normal operating conditions. As shown in
Figure 49, when a rising voltage on EN crosses the upper threshold,
nominally 1.22 V, V OUT turns on. When a falling voltage on EN
crosses the lower threshold, nominally 1.13 V, V OUT turns off.
The hysteresis of the EN threshold is approximately 90 mV.
R
EN1 = REN2 × (VIN − 1.22 V)/1.22 V
where:
EN2 typically ranges from 10 kΩ to 100 kΩ.
IN is the desired turn-on voltage.
R
V
3.5
+125°C
+85°C
+25°C
The hysteresis voltage increases by the factor
3.0
–5°C
–40°C
(REN1 + REN2)/REN2
2.5
2.0
1.5
1.0
0.5
0
For the example shown in Figure 52, the EN threshold is 2.44 V
with a hysteresis of 200 mV.
ADM7154
V
= 2.3V
V
= 1.8V
OUT
IN
VIN
VOUT
C
C
IN
OUT
10µF
10µF
R
EN1
ON
100kΩ
EN
REF
C
REF
1µF
OFF
R
EN2
100kΩ
BYP REF_SENSE
C
BYP
1µF
1.0
1.1
1.2
1.3
VREG
GND
EN PIN VOLTAGE (V)
C
10µF
REG
Figure 49. Typical VOUT Response to EN Pin Operation
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
ENABLE (V
)
EN
Figure 52. Typical EN Pin Voltage Divider
V
OUT
Figure 52 shows the typical hysteresis of the EN pin. This
prevents on/off oscillations that can occur due to noise on the
EN pin as it passes through the threshold points.
START-UP TIME
The ADM7154 uses an internal soft start to limit the inrush current
when the output is enabled. The start-up time for a 3.3 V output is
approximately 1.2 ms from the time the EN active threshold is
crossed to when the output reaches 90% of the final value.
The rise time in seconds of the output voltage (10% to 90%) is
approximately
0
0.4
0.8
1.2
1.6
2.0
2.4
2.8
3.2
3.6
4.0
TIME (ms)
0.0012 × CBYP
Figure 50. Typical VOUT Response to EN Pin Operation (VEN),
OUT = 3.3 V, VIN = 5 V, CBYP = 1 µF
where CBYP is in microfarads.
V
3.5
1.250
1.225
1.200
1.175
1.150
1.125
1.100
3.0
2.5
2.0
1.5
1.0
–40°C RISING
+25°C RISING
+125°C RISING
–40°C FALLING
+25°C FALLING
+125°C FALLING
ENABLE (V
)
EN
C
C
C
= 1µF
= 3.3µF
= 10µF
BYP
BYP
BYP
0.5
0
0
5
10
15
20
25
30
35
40
2.5
3.0
3.5
4.0
4.5
5.0
5.5
TIME (ms)
INPUT VOLTAGE (V)
Figure 53. Typical Start-Up Behavior with CBYP = 1 µF to 10 µF
Figure 51. Typical EN Threshold vs. Input Voltages (VIN) for Different
Temperatures
Rev. B | Page 17 of 23
ADM7154
Data Sheet
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
Current-limit and thermal limit protections are intended to
protect the device against accidental overload conditions. For
reliable operation, device power dissipation must be externally
limited so that the junction temperature does not exceed 150°C.
THERMAL CONSIDERATIONS
In applications with a low input to output voltage differential,
the ADM7154 does not dissipate much heat. However, in
applications with high ambient temperature and/or high input
voltage, the heat dissipated in the package can become large
enough that it causes the junction temperature of the die to
exceed the maximum junction temperature of 150°C.
ENABLE (V
)
EN
C
C
C
C
= 10µF
= 33µF
= 100µF
= 330µF
BYP
BYP
BYP
BYP
When the junction temperature exceeds 150°C, the converter
enters thermal shutdown. It recovers only after the junction
temperature decreases below 135°C to prevent any permanent
damage. Therefore, thermal analysis for the chosen application
is important to guarantee reliable performance over all condi-
tions. The junction temperature of the die is the sum of the
ambient temperature of the environment and the temperature
rise of the package due to the power dissipation, as shown in
Equation 2.
0
20
40
60
80
100 120 140 160 180 200
TIME (ms)
Figure 54. Typical Start-Up Behavior with CBYP = 10 µF to 330 µF
REF, BYP, AND VREG PINS
REF, BYP, and VREG generate voltages internally (VREF, VBYP
and VREG) that require external bypass capacitors for proper
operation. Do not, under any circumstances, connect any loads
to these pins, because doing so compromises the noise and
PSRR performance of the ADM7154. Using larger values of
,
To guarantee reliable operation, the junction temperature of the
ADM7154 must not exceed 150°C. To ensure that the junction
temperature stays below this maximum value, the user must be
aware of the parameters that contribute to junction temperature
changes. These parameters include ambient temperature, power
dissipation in the power device, and thermal resistances between
the junction and ambient air (θJA). The θJA number is dependent
on the package assembly compounds that are used and the
amount of copper used to solder the package GND pin and
exposed pad to the PCB.
C
BYP, CREF, and CREG is acceptable but can increase the start-up
time, as described in the Start-Up Time section.
CURRENT-LIMIT AND THERMAL OVERLOAD
PROTECTION
The ADM7154 is protected against damage due to excessive
power dissipation by current and thermal overload protection
circuits. The ADM7154 is designed to current limit when the
output load reaches 960 mA (typical). When the output load
exceeds 960 mA, the output voltage is reduced to maintain a
constant current limit.
Table 7 shows typical θJA values of the 8-lead SOIC and 8-lead
LFCSP packages for various PCB copper sizes.
Thermal overload protection is included, which limits the
junction temperature to a maximum of 150°C. Under extreme
conditions (that is, high ambient temperature and/or high
power dissipation), when the junction temperature starts to rise
above 150°C, the output is turned off, reducing the output
current to zero. When the junction temperature drops below
135°C, the output is turned on again, and the output current is
restored to the operating value.
Table 8 shows the typical ΨJB values of the 8-lead SOIC and
8-lead LFCSP.
Table 7. Typical θJA Values
θJA (°C/W)
Copper Size (mm2)
251
8-Lead LFCSP
165.1
8-Lead SOIC
165
100
500
125.8
68.1
126.4
69.8
Consider the case where a hard short from VOUT to GND
occurs. At first, the ADM7154 current limits, so that only
960 mA is conducted into the short. If self heating of the
junction is great enough to cause the temperature to rise above
150°C, thermal shutdown activates, turning off the output and
reducing the output current to zero. As the junction tempera-
ture cools and drops below 135°C, the output turns on and
conducts 900 mA into the short, again causing the junction
temperature to rise above 150°C. This thermal oscillation
between 135°C and 150°C causes a current oscillation between
900 mA and 0 mA that continues for as long as the short
remains at the output.
1000
6400
56.4
42.1
57.8
43.6
1 Device soldered to minimum size pin traces.
Table 8. Typical ΨJB Values
Package
ΨJB (°C/W)
8-Lead LFCSP
8-Lead SOIC
15.1
17.9
Rev. B | Page 18 of 23
Data Sheet
ADM7154
160
150
140
130
120
110
100
90
The junction temperature of the ADM7154 is calculated from
the following equation:
TJ = TA + (PD × θJA)
(2)
where:
TA is the ambient temperature.
PD is the power dissipation in the die, given by
PD = ((VIN − VOUT) × ILOAD) + (VIN × IGND
where:
IN and VOUT are the input and output voltages, respectively.
)
(3)
80
2
6400mm
V
70
2
500mm
2
I
I
LOAD is the load current.
GND is the ground current.
25mm
60
T
MAX
J
50
0
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4
TOTAL POWER DISSIPATION (W)
Power dissipation caused by ground current is quite small and
can be ignored. Therefore, the junction temperature equation
simplifies to the following:
Figure 56. Junction Temperature vs. Total Power Dissipation for
the 8-Lead LFCSP, TA = 50°C
155
145
135
125
115
105
95
TJ = TA + (((VIN − VOUT) × ILOAD) × θJA)
(4)
As shown in Equation 4, for a given ambient temperature, input
to output voltage differential, and continuous load current,
there exists a minimum copper size requirement for the PCB to
ensure that the junction temperature does not rise above 150°C.
The heat dissipation from the package can be improved by
increasing the amount of copper attached to the pins and
exposed pad of the ADM7154. Adding thermal planes
underneath the package also improves thermal performance.
However, as shown in Table 7, a point of diminishing returns is
eventually reached, beyond which an increase in the copper
area does not yield significant reduction in the junction to
ambient thermal resistance.
85
75
65
2
6400mm
2
500mm
2
25mm
T
MAX
J
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5
TOTAL POWER DISSIPATION (W)
Figure 55 to Figure 60 show junction temperature calculations
for different ambient temperatures, power dissipation, and areas
of PCB copper.
Figure 57. Junction Temperature vs. Total Power Dissipation for
the 8-Lead LFCSP, TA = 85°C
155
145
135
125
115
105
95
155
145
135
125
115
105
95
85
75
65
85
75
65
2
6400mm
2
500mm
55
45
35
25
2
6400mm
2
25mm
2
500mm
T
MAX
J
2
25mm
T
MAX
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5
TOTAL POWER DISSIPATION (W)
J
0
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0
TOTAL POWER DISSIPATION (W)
Figure 58. Junction Temperature vs. Total Power Dissipation for
the 8-Lead SOIC, TA = 25°C
Figure 55. Junction Temperature vs. Total Power Dissipation for
the 8-Lead LFCSP, TA = 25°C
Rev. B | Page 19 of 23
ADM7154
Data Sheet
160
150
140
130
120
110
100
90
Thermal Characterization Parameter (ΨJB)
When board temperature is known, use the thermal
characterization parameter, ΨJB, to estimate the junction
temperature rise (see Figure 61 and Figure 62). Maximum
junction temperature (TJ) is calculated from the board
temperature (TB) and power dissipation (PD) using the following
formula:
TJ = TB + (PD × ΨJB)
(5)
80
2
The typical value of ΨJB is 15.1°C/W for the 8-lead LFCSP
package and 17.9°C/W for the 8-lead SOIC package.
6400mm
70
2
500mm
2
25mm
60
160
T
MAX
J
50
0
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4
TOTAL POWER DISSIPATION (W)
140
120
100
80
Figure 59. Junction Temperature vs. Total Power Dissipation for
the 8-Lead SOIC, TA = 50°C
155
145
135
125
115
105
95
60
T
T
T
T
T
= 25°C
= 50°C
= 65°C
= 85°C
MAX
B
B
B
B
J
40
20
0
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0
TOTAL POWER DISSIPATION (W)
85
75
65
2
6400mm
Figure 61. Junction Temperature vs. Total Power Dissipation for
the 8-Lead LFCSP
2
500mm
2
25mm
160
140
120
100
80
T
MAX
1.8
J
0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
2.0
TOTAL POWER DISSIPATION (W)
Figure 60. Junction Temperature vs. Total Power Dissipation for
the 8-Lead SOIC, TA = 85°C
60
T
T
T
T
T
= 25°C
= 50°C
= 65°C
= 85°C
MAX
B
B
B
B
J
40
20
0
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5
TOTAL POWER DISSIPATION (W)
Figure 62. Junction Temperature vs. Total Power Dissipation for
the 8-Lead SOIC
Rev. B | Page 20 of 23
Data Sheet
ADM7154
PCB LAYOUT CONSIDERATIONS
Place the input capacitor as close as possible to the VIN and
GND pins. Place the output capacitor as close as possible to the
VOUT and GND pins. Place the bypass capacitors (CREG, CREF
and CBYP) for VREG, VREF, and VBYP close to the respective pins
(VREG, REF, and BYP) and GND. Use of an 0805, 0603, or
0402 size capacitor achieves the smallest possible footprint
solution on boards where area is limited.
,
Figure 64. Example 8-Lead SOIC PCB Layout
Figure 63. Example 8-Lead LFCSP PCB Layout
Rev. B | Page 21 of 23
ADM7154
Data Sheet
OUTLINE DIMENSIONS
2.54
2.44
2.34
3.10
3.00 SQ
2.90
0.50 BSC
5
8
PIN 1 INDEX
EXPOSED
PAD
1.70
1.60
1.50
AREA
0.50
0.40
0.30
0.20 MIN
4
1
TOP VIEW
PIN 1
BOTTOM VIEW
INDICATOR
(R 0.20)
0.80
0.75
0.70
FOR PROPER CONNECTION OF
THE EXPOSED PAD, REFER TO
THE PIN CONFIGURATION AND
FUNCTION DESCRIPTIONS
0.05 MAX
0.02 NOM
SECTION OF THIS DATA SHEET.
0.30
0.25
0.20
SEATING
PLANE
0.203 REF
Figure 65. 8-Lead Lead Frame Chip Scale Package [LFCSP_WD]
3 mm × 3 mm Body, Very Very Thin, Dual Lead
(CP-8-21)
Dimensions shown in millimeters
5.00
4.90
4.80
2.29
0.356
5
6.20
6.00
5.80
8
4.00
3.90
3.80
2.29
0.457
4
1
FOR PROPER CONNECTION OF
THE EXPOSED PAD, REFER TO
THE PIN CONFIGURATION AND
FUNCTION DESCRIPTIONS
BOTTOM VIEW
45°
1.27 BSC
3.81 REF
TOP VIEW
SECTION OF THIS DATA SHEET.
1.65
1.25
1.75
1.35
0.50
0.25
0.25
0.17
0.10 MAX
0.05 NOM
SEATING
PLANE
8°
0°
0.51
0.31
1.04 REF
COPLANARITY
0.10
1.27
0.40
COMPLIANT TO JEDEC STANDARDS MS-012-AA
Figure 66. 8-Lead Standard Small Outline Package, with Exposed Pad [SOIC_N_EP]
Narrow Body
(RD-8-1)
Dimensions shown in millimeters
Rev. B | Page 22 of 23
Data Sheet
ADM7154
ORDERING GUIDE
Model1
Temperature Range
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
Output Voltage (V)
Package Description
8-Lead LFCSP_WD
8-Lead LFCSP_WD
8-Lead LFCSP_WD
8-Lead LFCSP_WD
8-Lead LFCSP_WD
8-Lead LFCSP_WD
8-Lead SOIC_N_EP
8-Lead SOIC_N_EP
8-Lead SOIC_N_EP
8-Lead SOIC_N_EP
8-Lead SOIC_N_EP
8-Lead SOIC_N_EP
Evaluation Board
Evaluation Board
Package Option
CP-8-21
CP-8-21
CP-8-21
CP-8-21
CP-8-21
CP-8-21
RD-8-1
RD-8-1
RD-8-1
RD-8-1
RD-8-1
Branding
LQS
LQT
LQU
LQ6
ADM7154ACPZ-1.2-R7
ADM7154ACPZ-1.8-R7
ADM7154ACPZ-2.5-R7
ADM7154ACPZ-2.8-R7
ADM7154ACPZ-3.0-R7
ADM7154ACPZ-3.3-R7
ADM7154ARDZ-1.2-R7
ADM7154ARDZ-1.8-R7
ADM7154ARDZ-2.5-R7
ADM7154ARDZ-2.8-R7
ADM7154ARDZ-3.0-R7
ADM7154ARDZ-3.3-R7
ADM7154CP-3.3EVALZ
ADM7154RD-1.8EVALZ
1.2
1.8
2.5
2.8
3.0
3.3
1.2
1.8
2.5
2.8
3.0
3.3
LRF
LQ7
RD-8-1
1 Z = RoHS Compliant Part.
©2014–2016 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D12324-0-8/16(B)
Rev. B | Page 23 of 23
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