−500 mA, Ultralow Noise, High PSRR,
Low Dropout Linear Regulator
Data Sheet ADP7185
Rev. 0 Document Feedback
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FEATURES
Input voltage range: −2.0 V to −5.5 V
Maximum output current: −500 mA
Fixed output voltage options: −0.5 V to −4.5 V
Adjustable output from −0.5 V to −VIN + 0.5 V
Low output noise: 4 μV rms from 100 Hz to 100 kHz
Noise spectral density: 20 nV/√Hz, 10 kHz to 1 MHz
PSRR at −500 mA load
68 dB at 10 kHz
50 dB at 100 kHz
40 dB at 1 MHz
Low dropout voltage: −190 mV typical at −500 mA load
Initial output voltage (VOUT) accuracy: ±0.5%
Output voltage accuracy over line, load, and temperature:
±2.2%
Operating supply current (IGND): −0.6 mA typical at no load
Low shutdown current: −2 μA typical at VIN = −5.5 V
Stable with small 4.7 μF ceramic input and output capacitor
Positive or negative enable logic
Current-limit and thermal overload protection
8-lead, 2 mm × 2 mm LFCSP package
Supported by ADIsimPOWER voltage regulator design tool
APPLICATIONS
Regulation to noise sensitive applications: analog-to-digital
converters (ADCs), digital-to-analog converters (DACs),
precision amplifiers
Communications and infrastructure
Medical and healthcare
Industrial and instrumentation
TYPICAL APPLICATION CIRCUITS
V
OUT
= –3.3V
C
OUT
4.7µF
C
A
1µF
C
AFB
10nF
+1.25V
0V
–1.3V
OFF
ON
VIN
EN
VREG GND
VOUT
SENSE
VA
VAFB
C
IN
4.7µF
V
IN
= –3.8V
C
REG
1µF
ADP7185
EP
13932-001
Figure 1. ADP7185 with Fixed Output Voltage, −3.3 V
VOUT = –2.5V
COUT
4.7µF
+1.25V
0V
–1.3V
OFF
ON
VIN
EN
VREG GND
VOUT
SENSE
VA
VAFB
CIN
4.7µF
VIN = –3V
CREG
1µF
ADP7185
CA
1µF
CAFB
10nF
R2
24.9k
R1
100k
EP
13932-002
Figure 2. ADP7185 with Adjustable Output Voltage, VOUT = −2.5 V
GENERAL DESCRIPTION
The ADP7185 is a complementary metal oxide semiconductor
(CMOS), low dropout (LDO) linear regulator that operates
from −2.0 V to −5.5 V and provides up to −500 mA of output
current. This high output current LDO is ideal for regulation of
high performance analog and mixed signal circuits operating
from −0.5 V down to −4.5 V. Using an advanced proprietary
architecture, the ADP7185 provides high power supple rejection
ratio (PSRR) and low noise, and it achieves excellent line and load
transient response with a small 4.7 μF ceramic output capacitor.
The ADP7185 is available in 15 fixed output voltage options.
The following voltages are available from stock: −0.5 V, −1.0 V,
−1.2 V, −1.5 V, −1.8 V, −2.0 V, −2.5 V, −3.0 V, and −3.3 V.
Additional voltages available by special order are −0.8 V, −0.9 V,
−1.3 V, −2.8 V, −4.2 V, and −4.5 V. An adjustable version is also
available which allows output voltages that range from −0.5 V to
−VIN + 0.5 V with an external feedback divider.
The enable logic feature is capable of interfacing with positive
or negative logic levels for maximum flexibility.
The ADP7185 regulator output noise is 4 μV rms independent
of the output voltage. The ADP7185 is available in an 8-lead,
2 mm × 2 mm LFCSP, making it not only a very compact
solution but also providing excellent thermal performance for
applications requiring up to −500 mA of output current in a
small, low profile footprint.
ADP7185 Data Sheet
Rev. 0 | Page 2 of 19
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications ....................................................................................... 1
Typical Application Circuits ............................................................ 1
General Description ......................................................................... 1
Revision History ............................................................................... 2
Specifications ..................................................................................... 3
Input and Output Capacitor Recommended Specifications ... 4
Absolute Maximum Ratings ............................................................ 5
Thermal Data ................................................................................ 5
Thermal Resistance ...................................................................... 5
ESD Caution .................................................................................. 5
Pin Configuration and Function Descriptions ............................. 6
Typical Performance Characteristics ............................................. 7
Theory of Operation ...................................................................... 13
Adjustable Mode Operation ..................................................... 13
Enable Pin Operation ................................................................ 13
Start-Up Time ............................................................................. 14
Applications Information .............................................................. 15
ADIsimPower Design Tool ....................................................... 15
Capacitor Selection .................................................................... 15
Undervoltage Lockout (UVLO) ............................................... 16
Current-Limit and Thermal Overload Protection ................. 16
Thermal Considerations ............................................................ 17
Outline Dimensions ....................................................................... 19
Ordering Guide .......................................................................... 19
REVISION HISTORY
5/2017—Revision 0: Initial Version
Data Sheet ADP7185
Rev. 0 | Page 3 of 19
SPECIFICATIONS
VIN = (VOUT − 0.5 V) or −2 V (whichever is more negative), EN = VIN, IOUT = −10 mA, CIN = COUT = 4.7 μF, CAFB = 10 nF, CA = CREG = 1 μF, TA =
25°C for typical specifications, and TJ = −40°C to +125°C for minimum/maximum specications, unless otherwise noted.
Table 1.
Parameter Symbol Test Conditions/Comments Min Typ Max Unit
INPUT VOLTAGE RANGE VIN −2.0 −5.5 V
LOAD CURRENT ILOAD −500 mA
OPERATING SUPPLY CURRENT IGND I
OUT = 0 µA −0.6 −0.90 mA
I
OUT = −500 mA −5.5 −7.0 mA
SHUTDOWN CURRENT IGND-SD EN = GND, VIN = −5.5 V −2 −7 µA
OUTPUT NOISE1 OUTNOISE 10 Hz to 100 kHz, CAFB = 1 nF 7 µV rms
10 Hz to 100 kHz, CAFB = 10 nF 5 µV rms
100 Hz to 100 kHz, CAFB = 1 nF 6 µV rms
100 Hz to 100 kHz, CAFB = 10 nF 4 µV rms
NOISE SPECTRAL DENSITY1 OUTNSD 100 Hz, CAFB = 1 nF 300 nV/√Hz
100 Hz, CAFB = 10 nF 100 nV/√Hz
10 kHz to 1 MHz, CAFB=1 nF to 1 F 20 nV/√Hz
POWER SUPPLY REJECTION RATIO1 PSRR IOUT = −500 mA, VOUT = −3.3 V, VIN = −3.8 V
At 1 kHz 80 dB
At 10 kHz 68 dB
At 100 kHz 50 dB
At 1 MHz 40 dB
OUTPUT VOLTAGE VOUT –0.5 –4.5 V
Accuracy IOUT = −10 mA, TA = 25°C –0.5 +0.5 %
−1 mA < IOUT < −500 mA, VIN = (VOUT − 0.5 V)
to −5.5 V
–2.2 +2.2 %
OUTPUT VOLTAGE REFERENCE FEEDBACK VAFB Adjustable model voltage reference −0.489 −0.5 −0.511 V
VAFB Accuracy Adjustable model, −1 mA < IOUT < −500 mA,
VIN = (VOUT − 0.5 V) to −5.5 V
−2.2 +2.2 %
LINE REGULATION ∆VOUT/VIN V
IN = (VOUT − 0.5 V) to −5.5 V −0.1 +0.3 %/V
LOAD REGULATION2 VOUT/IOUT I
OUT = −1 mA to −500 mA 0.6 1.8 %/A
INPUT BIAS CURRENT
SENSE SENSEI-BIAS −1 mA < IOUT < −500 mA, VIN = (VOUT − 0.5 V)
to −5.5 V
−10 nA
VAFB VAFB-BIAS −1 mA < IOUT < −500 mA, VIN = (VOUT − 0.5 V)
to −5.5 V
−10 nA
DROPOUT VOLTAGE3 V
DROPOUT I
OUT = −100 mA −30 −60 mV
I
OUT = −500 mA −190 −360 mV
PULL-DOWN RESISTANCE VEN = 0 V
Output Voltage VOUT-PULL V
OUT = −1 V 280
Regulated Input Supply Voltage VREG-PULL V
REG = −1 V 1.3 kΩ
Low-Noise Reference Voltage VA-PULL V
A = −1 V 61
START-UP TIME4 T
START-UP V
OUT = −4.5 V, CAFB = 1 nF, CA = 1 µF 15 ms
V
OUT = −4.5 V, CAFB = 10 nF, CA = 1 µF 55 ms
V
OUT = −1.2 V, CAFB = 1 nF, CA = 1 µF 4 ms
V
OUT = −1.2 V, CAFB = 10 nF, CA = 1 µF 10 ms
V
OUT = −0.5 V, no CAFB, CA = 1 µF 1.5 ms
CURRENT-LIMIT THRESHOLD5 I
LIMIT −600 −900 −1100 mA
THERMAL SHUTDOWN
Threshold TSSD T
J rising 150 °C
Hysteresis TSSD-HYS 15 °C
ADP7185 Data Sheet
Rev. 0 | Page 4 of 19
Parameter Symbol Test Conditions/Comments Min Typ Max Unit
UNDERVOLTAGE LOCKOUT THRESHOLDS
Input Voltage
Rising UVLORISE −1.77 V
Falling UVLOFALL −1.58 V
Hysteresis UVLOHYS 90 mV
EN INPUT (NEGATIVE) −2 V ≤ VIN ≤ −5.5 V
Logic High VEN-NEG-HIGH V
OUT = off to on −1.3 −1.16 V
Logic Low VEN-NEG_LOW V
OUT = on to off −0.96 -0.88 V
Hysteresis ENHYS-NEG 191 mV
Leakage Current IEN-LKG EN = VIN or GND −0.25 µA
EN INPUT (POSITIVE) −2 V ≤ VIN ≤ −5.5 V
Logic High VEN-POS-HIGH V
OUT = off to on 0.96 1.25 V
Logic Low VEN-POS-LOW V
OUT = on to off 0.5 0.89 V
Leakage Current IEN-LKG V
EN = 5 V, VIN = −5.5 V 4.0 6.0 µA
1 Guaranteed by characterization but not production tested.
2 Based on an endpoint calculation using −1 mA and −500 mA loads.
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 below −2 V.
4 Start-up time is defined as the time between the rising edge of EN to VOUT being at 90% of its nominal value.
5 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 threshold 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.
INPUT AND OUTPUT CAPACITOR RECOMMENDED SPECIFICATIONS
Table 2.
Parameter Symbol Test Conditions/Comments Min Typ Max Unit
CAPACITANCE TA = −40°C to +125°C
Minimum CIN and COUT Capacitance1 C
IN, COUT 3.3 4.7 µF
Minimum CA and CREG Capacitance2 CA, CREG 0.7 1 µF
Minimum CAFB Capacitance3 C
AFB 0.7 10 nF
Capacitor Equivalent Series Resistance (ESR) RESR 0.1
1 The minimum input and output capacitance must be greater than 3.3 µF over the full range of operating conditions. X7R and X5R type capacitors are recommended;
Y5V and Z5U capacitors are not recommended for use with any LDO.
2 The minimum CA and CREG capacitance must be greater than 0.7 µF over the full range of operating conditions. X7R and X5R type capacitors are recommended; Y5V
and Z5U capacitors are not recommended for use with any LDO.
3 The minimum CAFB capacitance must be greater than 0.7 nF over the full range of operating conditions. X7R and X5R type capacitors are recommended; Y5V and Z5U
capacitors are not recommended for use with any LDO.
Data Sheet ADP7185
Rev. 0 | Page 5 of 19
ABSOLUTE MAXIMUM RATINGS
Table 3.
Parameter Rating
VIN to GND +0.3 V to −6 V
VOUT to GND +0.3 V to −VIN
EN to GND +5.0 V to −6 V
VA to GND +0.3 V to −6 V
VAFB to GND +0.3 V to −6 V
VREG to GND +0.3 V to −2.16 V
SENSE to GND +0.3 V to −6 V
Storage Temperature Range −65°C to +150°C
Operating Junction 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.
THERMAL DATA
Absolute maximum ratings apply individually only, not in
combination. The ADP7185 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 temperature may
have to be derated.
In applications with moderate power dissipation and low printed
circuit board (PCB) thermal resistance, the maximum ambient
temperature can exceed the maximum limit as long as 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).
Use the following equation to calculate the junction temperature
(TJ) from the ambient temperature (TA) and power dissipation (PD):
TJ = TA + (PD × θJA)
The junction to ambient thermal resistance (θJA) of the package
is based on modeling and calculation using a 4-layer board. The
junction to ambient thermal resistance is highly dependent on
the application and board layout. In applications where high
maximum power dissipation exists, close attention to thermal
board design is required. The θJA value may vary, depending on
the PCB material, layout, and environmental conditions. The
specified θJA values are based on a 4-layer, 4 in. × 3 in. circuit board.
THERMAL RESISTANCE
Thermal performance is directly linked to printed circuit board
(PCB) design and operating environment. Careful attention to
PCB thermal design is required.
Table 4. Thermal Resistance
Package Type θJA θ
JC Unit
CP-8-27 68.8 10.0 °C/W
ESD CAUTION
ADP7185 Data Sheet
Rev. 0 | Page 6 of 19
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
3VA
4VAFB
1VOUT
2SENSE
6GND
5EN
8VIN
7VREG
NOTES
1. EXPOSED PAD. THE EXPOSED PAD ENHANCES THE
THERMAL PERFORMANCE AND IS ELECTRICALLY
CONNECTED TO VIN INSIDE THE PACKAGE. IT IS
RECOMMENDED THAT THE EXPOSED PAD CONNECT
TO THE INPUT VOLTAGE PLANE ON THE BOARD.
ADP7185
TOP VIEW
(Not to Scale)
13932-003
Figure 3. Pin Configuration
Table 5. Pin Function Descriptions
Pin No. Mnemonic Description
1 VOUT Regulated Output Voltage. Bypass VOUT to GND with a 4.7 µF or greater capacitor.
2 SENSE Sense Input. Connect this pin to VOUT.
3 VA Low Noise Reference Voltage. Connect a 1 µF capacitor to GND to reduce noise. Do not connect a load to ground.
4 VAFB
Output Voltage Reference Feedback (Adjust Mode). Connect a 1 nF to 1 µF capacitor between the VAFB pin and
the VA pin to reduce noise. Start-up time is increased as a function of the capacitance. Connect an external resistor
divider between the VA pin and the VAFB pin to set the output voltage in adjust mode.
5 EN Enable. Drive EN at least +1.25 V above or −1.3 V below ground to enable the regulator or drive EN to ground to
turn the regulator off. For automatic startup, connect EN to VIN.
6 GND Ground.
7 VREG
Regulated Input Supply to the LDO Amplifier. Bypass VREG to GND with a 1 µF or greater capacitor. Do not
connect a load to ground.
8 VIN Regulator Input Supply. Bypass VIN to GND with a 4.7 µF or greater capacitor.
EP Exposed pad. The exposed pad enhances the thermal performance and is electrically connected to VIN inside the
package. It is recommended that the exposed pad connect to the input voltage plane on the board.
Data Sheet ADP7185
Rev. 0 | Page 7 of 19
TYPICAL PERFORMANCE CHARACTERISTICS
VIN = −3.8 V, VOUT = −3.3 V, IOUT = −10 mA, CIN = COUT = 4.7 μF, CAFB = 10 nF, CA = CREG = 1 μF, and TA = 25°C, unless otherwise noted.
V
OUT
(V)
TEMPERATUREC)
–40–60 –20 140120100806040200
–1.216
–1.211
–1.206
–1.201
–1.196
–1.191
1.186
NO LOAD
I
LOAD
=–10mA
I
LOAD
= –100mA
I
LOAD
= –300mA
I
LOAD
= –500mA
13932-304
Figure 4. Output Voltage (VOUT) vs. Junction Temperature, VOUT = −1.2 V
VOUT (V)
ILOAD (mA)
–1000 –10–100
–1.216
–1.211
–1.206
–1.201
–1.196
–1.191
1.186
13932-305
Figure 5. Output Voltage (VOUT) vs. Load Current (ILOAD), VOUT = −1.2 V
V
OUT
(V)
V
IN
(V)
–5.5 –5.0 4.5 –4.0 –3.5 3.0 –2.5 –2.0
–1.246
–1.236
–1.226
–1.216
–1.206
–1.196
1.186
NO LOAD
I
LOAD
=–10mA
I
LOAD
= –100mA
I
LOAD
= –300mA
I
LOAD
= –500mA
13932-306
Figure 6. Output Voltage (VOUT) vs. Input Voltage (VIN), VOUT = −1.2 V
GROUND CURRENT (mA)
JUNCTION TEMPERATURE (°C)
–1540 10356085110135
–8
–7
–6
–5
–4
–3
–2
–1
0
13932-017
NO LOAD
I
LOAD
=–10mA
I
LOAD
= –100mA
I
LOAD
= –300mA
I
LOAD
= –500mA
Figure 7. Ground Current vs. Junction Temperature (TJ), VOUT = −1.2 V
I
LOAD
(mA)
GROUND CURRENT (mA)
–6
–5
–4
–3
–2
–1
0
–500 –450 –400 –350 –300 –250 –200 –150 –100 –50 0
13932-018
Figure 8. Ground Current vs. Load Current (ILOAD), VOUT = −1.2 V
GROUND CURRENT (mA)
V
IN
(V)
–5.5 –5.0 –4.5 –4.0 –3.5 –3.0 –2.5 –2.0
–8
–7
–6
–5
–4
–3
–2
–1
0
13932-019
NO LOAD
I
LOAD
= –10mA
I
LOAD
= –100mA
I
LOAD
= –300mA
I
LOAD
= –500mA
Figure 9. Ground Current vs. Input Voltage (VIN), VOUT = −1.2 V
ADP7185 Data Sheet
Rev. 0 | Page 8 of 19
SHUTDOWN CURRENT (µA)
JUNCTION TEMPERATURE (°C)
–5.0
–4.5
–4.0
–3.5
–3.0
–2.5
–2.0
–1.5
–1.0
–0.5
0
–40 –15 10 35 60 85 110 135
V
IN
= –2.0V
V
IN
= –2.5V
V
IN
= –3.0V
V
IN
= –3.5V
V
IN
= –4.0V
V
IN
= –4.5V
V
IN
= –5.0V
V
IN
= –5.5V
13932-020
Figure 10. Shutdown Current vs. Junction Temperature at Various Input Voltages,
VOUT = −1.2 V
V
OUT
(V)
TEMPERATURE (°C)
–40–60 –20 140120100806040200
NO LOAD
I
LOAD
= –10mA
I
LOAD
= –100mA
I
LOAD
= –300mA
I
LOAD
= –500mA
–2.555
–2.535
–2.515
–2.495
–2.475
–2.455
2.435
13932-311
Figure 11. Output Voltage (VOUT) vs. Junction Temperature (TJ), VOUT = −2.5 V
VOUT (V)
ILOAD (mA)
–1000 –10–100
–2.555
–2.535
–2.515
–2.495
–2.475
2.455
13932-312
Figure 12. Output Voltage (VOUT) vs. Load Current (ILOAD), VOUT = −2.5 V
V
OUT
(V)
V
IN
(V)
–5.5 –5.0 –4.5 –4.0 –3.5 –3.0
NO LOAD
I
LOAD
=–10mA
I
LOAD
= –100mA
I
LOAD
= –300mA
I
LOAD
= –500mA
–2.575
–2.555
–2.535
–2.515
–2.495
–2.475
–2.455
2.435
13932-313
Figure 13. Output Voltage (VOUT) vs. Input Voltage (VIN), VOUT = −2.5 V
I
LOAD
(mA)
GROUND CURRENT (mA)
–6
–5
–4
–3
–2
–1
0
–500 –450 –400 –350 –300 –250 –200 –150 –100 –50 0
13932-024
Figure 14. Ground Current vs. Load Current (ILOAD), VOUT = −2.5 V
GROUND CURRENT (mA)
V
IN
(V)
–8
–7
–6
–5
–4
–3
–2
–1
0
–5.5 –5.0 –4.5 –4.0 –3.5 –3.0
13932-025
I
LOAD
= –10mA
I
LOAD
= –100mA
I
LOAD
= –200mA
I
LOAD
= –300mA
I
LOAD
= –500mA
Figure 15. Ground Current vs. Input Voltage (VIN), VOUT = −2.5 V
Data Sheet ADP7185
Rev. 0 | Page 9 of 19
DROPOUT VOLTAGE (mV)
I
LOAD
(mA)
–1000 –10–100
–200
–180
–160
–140
–120
–100
–80
–60
–40
–20
0
13932-316
Figure 16. Dropout Voltage vs Load Current (ILOAD), VOUT = −2.5 V
V
OUT
(V)
V
IN
(V)
–3.1 –2.4–2.5–2.6–2.7–2.8–2.9–3.0
NO LOAD
I
LOAD
=–10mA
I
LOAD
= –100mA
I
LOAD
= –300mA
I
LOAD
= –500mA
–2.52
–2.50
–2.48
–2.46
–2.44
–2.42
–2.40
–2.38
–2.36
–2.34
–2.32
–2.30
–2.28
–2.26
2.24
13932-317
Figure 17. Output Voltage (VOUT) vs. Input Voltage (VIN) in Dropout at
Various Loads, VOUT = −2.5 V
V
OUT
(V)
TEMPERATURE (°C)
–60 –40 –20 0 20 40 60 80 100 120 140
NO LOAD
I
LOAD
= –10mA
I
LOAD
= –100mA
I
LOAD
= –300mA
I
LOAD
= –500mA
–3.359
–3.339
–3.319
–3.299
–3.279
–3.259
3.239
13932-318
Figure 18. Output Voltage (VOUT) vs. Junction Temperature (TJ), VOUT = −3.3 V
V
OUT
(V)
I
LOAD
(mA)
–1000 –10–100
–3.369
–3.349
–3.329
–3.309
–3.289
–3.269
3.249
13932-319
Figure 19. Output Voltage (VOUT) vs. Load Current (ILOAD), VOUT = −3.3 V
V
OUT
(V)
V
IN
(V)
NO LOAD
I
LOAD
=–10mA
I
LOAD
= –100mA
I
LOAD
= –300mA
I
LOAD
= –500mA
–3.38
–3.36
–3.34
–3.32
–3.30
–3.28
3.26
–5.5 –5.3 –5.1 –4.9 –4.7 –4.5 –4.3 –4.1 –3.9
13932-320
Figure 20. Output Voltage (VOUT) vs. Input Voltage (VIN), VOUT = −3.3 V
GROUND CURRENT (mA)
JUNCTION TEMPERATURE (°C)
–15–40 10 35 60 85 110 135
–8
–7
–6
–5
–4
–3
–2
–1
0
13932-007
NO LOAD
ILOAD = –10mA
ILOAD = –100mA
ILOAD = –300mA
ILOAD = –500mA
Figure 21. Ground Current vs. Junction Temperature (TJ), VOUT = −3.3 V
ADP7185 Data Sheet
Rev. 0 | Page 10 of 19
I
LOAD
(mA)
GROUND CURRENT (mA)
–6
–5
–4
–3
–2
–1
0
–500 –450 –400 –350 300 –250 –200 –150 –100 –50 0
13932-008
Figure 22. Ground Current vs. Load Current (ILOAD), VOUT = −3.3 V
GROUND CURRENT (mA)
V
IN
(V)
–5.5 5.3 –5.1 –4.9 –4.7 –4.5 –4.3 –4.1 –3.9
–8
–7
–6
–5
–4
–3
–2
–1
0
13932-009
NO LOAD
I
LOAD
= –10mA
I
LOAD
= –100mA
I
LOAD
= –300mA
I
LOAD
= –500mA
Figure 23. Ground Current vs. Input Voltage (VIN), VOUT = −3.3 V
SHUTDOWN CURRENT (µA)
JUNCTION TEMPERATUREC)
–5.0
–4.5
–4.0
–3.5
–3.0
–2.5
–2.0
–1.5
–1.0
–0.5
0
V
IN
= –3.8V
V
IN
= –4.0V
V
IN
= –4.5V
V
IN
= –5.0V
V
IN
= –5.5V
40200 20406080100120140
13932-010
Figure 24. Shutdown Current vs. Junction Temperature at
Various Input Voltages, VOUT = −3.3 V
DROPOUT VOLTAGE (mV)
I
LOAD
(mA)
–1000 –10–100
–200
–180
–160
–140
–120
–100
–80
–60
–40
–20
0
13932-325
Figure 25. Dropout Voltage vs. Load Current (ILOAD), VOUT = −3.3 V
V
OUT
(V)
V
IN
(V)
–3.9 –3.8 3.7 3.6 –3.5 –3.4 –3.3 –3.2
NO LOAD
I
LOAD
= –10mA
I
LOAD
= –100mA
I
LOAD
= –300mA
I
LOAD
= –500mA
–3.32
3.14
–3.16
–3.18
–3.20
–3.22
–3.24
–3.26
–3.28
–3.30
13932-326
Figure 26. Output Voltage (VOUT) vs. Input Voltage (VIN) in Dropout at
Various Loads, VOUT = −3.3 V
GROUND CURRRENT (mA)
V
IN
(V)
–3.9 –2.7–2.9–3.1–3.3–3.5–3.7
I
LOAD
= –10mA
I
LOAD
= –100mA
I
LOAD
= –300mA
I
LOAD
= –500mA
–25
–20
–15
–10
–5
0
13932-327
Figure 27. Ground Current vs. Input Voltage (VIN) in Dropout at
Various Loads, VOUT = −3.3 V
Data Sheet ADP7185
Rev. 0 | Page 11 of 19
PSRR (dB)
FREQUENCY (Hz)
–100
–90
–80
–70
–60
–50
–40
–30
–20
–10
0
1 10 100 1k 10k 100k 1M 10M
I
LOAD
= –10mA
I
LOAD
= –100mA
I
LOAD
= –200mA
I
LOAD
= –300mA
I
LOAD
= –500mA
13932-031
Figure 28. Power Supply Rejection Ratio (PSRR) vs. Frequency at
Various Loads, VOUT = −1.2 V, VIN = −2 V
PSRR (dB)
FREQUENCY (Hz)
–100
–90
–80
–70
–60
–50
–40
–30
–20
–10
0
1 10 100 1k 10k 100k 1M 10M
ILOAD = –10mA
ILOAD = –100mA
ILOAD = –200mA
ILOAD = –300mA
ILOAD = –500mA
13932-032
Figure 29. Power Supply Rejection Ratio (PSRR) vs. Frequency at
Various Loads, VOUT = −2.5 V, VIN = −3 V
PSRR (dB)
FREQUENCY (Hz)
1 10 100 1k 10k 100k 1M 10M
–120
–110
–100
–90
–80
–70
–60
–50
–40
–30
–20
–10
0
ILOAD = –10mA
ILOAD = –100mA
ILOAD = –200mA
ILOAD = –300mA
ILOAD = –500mA
13932-033
Figure 30. Power Supply Rejection Ratio (PSRR) vs. Frequency at
Various Loads, VOUT = −3.3 V, VIN = −3.8 V
PSRR (dB)
FREQUENCY (Hz)
–100
–90
–80
–70
–60
–50
–40
–30
–20
–10
0
1 10 100 1k 10k 100k 1M 10M
13932-331
V
IN
= –2.0V
V
IN
= –2.1V
V
IN
= –2.2V
V
IN
= –2.3V
V
IN
= –2.4V
V
IN
= –2.5V
Figure 31. Power Supply Rejection Ratio (PSRR) vs. Frequency at
Various Input Voltages, VOUT = −1.2 V, ILOAD = −500 mA
PSRR (dB)
FREQUENCY (Hz)
–100
–90
–80
–70
–60
–50
–40
–30
–20
–10
0
1 10 100 1k 10k 100k 1M 10M
13932-332
V
IN
= –3.0V
V
IN
= –3.1V
V
IN
= –3.2V
V
IN
= –3.3V
V
IN
= –3.4V
V
IN
= –3.5V
Figure 32. Power Supply Rejection Ratio (PSRR) vs. Frequency at
Various Input Voltages, VOUT = −2.5 V, ILOAD = −500 mA
PSRR (dB)
FREQUENCY (Hz)
–110
–100
–90
–80
–70
–60
–50
–40
–30
–20
–10
0
1 10 100 1k 10k 100k 1M 10M
13932-333
V
IN
= –3.8V
V
IN
= –3.9V
V
IN
= –4.0V
V
IN
= –4.1V
V
IN
= –4.2V
V
IN
= –4.3V
Figure 33. Power Supply Rejection Ratio (PSRR) vs. Frequency at
Various Input Voltages, VOUT = −3.3 V, ILOAD = −500 mA
ADP7185 Data Sheet
Rev. 0 | Page 12 of 19
NOISE (µV rms)
LOAD CURRENT (mA)
–1000 –100 –10
3.80
3.85
3.90
3.95
4.00
4.05
4.10
4.15
4.20
4.25
4.30
4.35
4.40
10Hz TO 100kHz
100Hz TO 100kHz
13932-037
Figure 34. RMS Noise vs. Load Current (ILOAD) at Various Frequencies,
VIN = −3.8 V, VOUT = −3.3 V
NSD (nV/
Hz)
FREQUENCY (Hz)
10 100 1k 10k 100k 1M 10M
–4.5V ADJ
–4.5V
–3.3V
–2.5V
–1.2V
0.1
1
10
100
1k
10k
13932-335
Figure 35. Noise Spectral Density (NSD) vs. Frequency at Various Output Voltages,
VIN = −3.8 V, VOUT = −3.3 V
CH1 995mV
500mV/DIV
CH2 –2.00mV
2.0mV
5.0µs/DIV
1MS 20GS/s
STOP 40mV
EDGE POSITIVE
2
1
13932-336
VIN
VOUT
Figure 36. Line Transient Response, 500 mV Step, VOUT = −1.2 V, ILOAD = −500 mA
CH1 995mV
500mV/DIV
CH2 –20.5mV
2.0mV
5.0µs/DIV
1MS 20GS/s
STOP 40mV
EDGE POSITIVE
2
1
13932-337
VIN
VOUT
Figure 37. Line Transient Response, 500 mV Step, VOUT = −3.3 V, ILOAD = −500 mA
CH1 –475mA
500mA/DIV
CH2 5.0mV
9.9mV
10.0µs/DIV
2MS 20GS/s
STOP –220mA
EDGE POSITIVE
2
1
13932-338
ILOAD
VOUT
Figure 38. Load Transient Response, VOUT = −1.2 V, ILOAD = −10 mA to −500 mA
CH1 –215.0mA
200mA/DIV
CH2 3.6mV
2.0mV
10.0µs/DIV
2MS 20GS/s
STOP –222mA
EDGE POSITIVE
2
1
13932-339
ILOAD
VOUT
Figure 39. Load Transient Response, VOUT = −2.5 V, ILOAD = −10 mA to −500 mA
Data Sheet ADP7185
Rev. 0 | Page 13 of 19
THEORY OF OPERATION
The ADP7185 is a low quiescent current, LDO linear regulator
that operates from −2.0 V to −5.5 V and can provide up to
−500 mA of output current. Total integrated output noise is
4 μV rms independent of the output voltage, making it ideal for
high performance and noise sensitive applications. Shutdown
current consumption is −7 μA (maximum).
The ADP7185 is optimized for use with a 4.7 μF ceramic
capacitor for excellent transient performance. Using advanced
proprietary architecture, the ADP7185 provides ultralow noise
and high power supply rejection up to high frequencies of
operation. Figure 40 shows the fixed output voltage internal block
diagram of the ADP7185, and Figure 41 shows the adjustable
output voltage internal block diagram of the ADP7185.
R1
R2
VAFB
OVER CURRENT
THERMAL
PROTECTION
REFERENCE
–0.5V
REG
GND
VREG
EN
VIN
VA
SENSE
VOUT
GM
EN
13932-045
Figure 40. Fixed Output Voltage Internal Block Diagram
OVER CURRENT
THERMAL
PROTECTION
REFERENCE
–0.5V
REG
GND
VREG
EN
VIN
G
M
EN
VAFB
VA
SENSE
VOUT
R1
R2
13932-046
Figure 41. Adjustable Output Voltage Internal Block Diagram
Internally, the ADP7185 consists of a regulator block, reference
block, GM amplifier, feedback voltage divider, LDO regulator, and an
N-channel MOSFET pass transistor. The regulator block produces
an internal voltage rail (VREG) of −1.8 V to serve as the supply
voltage for the succeeding internal blocks. The GM amplifier
produces a reference voltage (VA) used as a reference to the
LDO regulator.
For fixed option models, the VA voltage is generated through the
resistor divider ratio depending on the VOUT option. For adjustable
models, the VA voltage generates externally through the R1 and
R2 resistors that are connected across the VA and VAFB pins.
Because the reference voltage to the LDO regulator already
adjusts according to the desired VOUT, the LDO regulator now
connects in a buffer configuration for improved noise performance.
If the load draws higher current, the LDO regulator pulls the gate
of the NMOS device higher towards GND to allow more current
to pass. If the load draws less current, the LDO regulator pulls
the gate of the NMOS device lower toward −VIN to restrict the
amount of current passing through the device.
ADJUSTABLE MODE OPERATION
The adjustable mode version of the ADP7185 has an output that
can be set to from −0.5 V to −4.5 V by an external voltage divider.
To calculate the output voltage, use the following equation:
VOUT = −0.5 V(1 + R1/R2) (1)
Figure 42 shows an example of an adjustable setting where R1 =
280 kΩ and R2 = 49.9 kΩ, setting the output voltage to −3.3 V.
R2 must be at least 10 kΩ to maximize PSRR performance.
C
IN
4.7µF
V
IN
= –3.8V
+1.25V
0V
–1.3V
OFF
ON
V
OUT
= –3.3V
C
REG
1µF
VIN
VREG
GND
EN
VOUT
SENSE
VA
VAFB
ADP7185
C
OUT
4.7µF
C
A
1µF
R1
280k
R2
49.9k
C
AFB
10nF
EP
13932-047
Figure 42. Setting the Adjustable Output Voltage
ENABLE PIN OPERATION
The ADP7185 uses the EN pin to enable and disable the VOUT pin
under normal operating conditions. When EN is +1.25 V above or
−1.3 V below with respect to GND, VOUT turns on, and when
EN is at 0 V, VOUT turns off, as shown in Figure 43. For
automatic startup, connect EN to VIN.
13932-149
CH1 1.0V
–15mV
CH2 1.0V
0mV
200ms/DIV
2MS 1MS/s
A CH2 40mV
2
EN
V
OUT
Figure 43. Typical EN Pin Operation
ADP7185 Data Sheet
Rev. 0 | Page 14 of 19
START-UP TIME
When the output is enabled, the ADP7185 uses an internal soft
start to limit the inrush current. The start-up time for a −1.2 V
output is approximately 12 ms from the time the EN active
threshold is crossed to the time when the output reaches 90%
of its final value (see Figure 44). As shown in Figure 44 and
Figure 45, the start-up time is dependent upon the output
voltage option and the value of the CAFB capacitor.
VOUT, EN (V)
TIME (ms)
EN
VOUT = –4.5V
VOUT = –3.3V
VOUT = –2.5V
VOUT = –1.2V
–6
–5
–4
–3
–2
–1
0
1
13932-244
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80
Figure 44. Start-Up Time at Various Output Voltages, CAFB = 10 nF, CA = 1 µF
The total start-up time depends mostly on the CA and CAFB
values expressed by the τ1 and τ2 equations (see Equation 2 and
Equation 3). During startup, an internal circuit, GM_START, turns
on and helps charge CA up to 90% of the final value. Estimate the
first time constant, τ1, due to CA by
τ1CA × ((R1 + R2)//ZOUT) (2)
During this time, keep ZOUT low to approximately 1 kΩ to allow
quick start-up times, keeping τ1 in the order of 1 ms.
V
OUT
(V)
TIME (ms)
13932-245
–4.5
–4.0
–3.5
–3.0
–2.5
–2.0
–1.5
–1.0
–0.5
0
0.5
10 30 50 70 90 110 130 150 170 190 210 230
EN
C
AFB
= 1nF
C
AFB
= 10nF
C
AFB
= 100nF
C
AFB
= 1µF
Figure 45. Start-Up Time at Various CAFB Capacitor Values, CA = 1 µF
A second time constant, τ2, is dependent mainly on CAFB. Figure 45
shows how the CAFB value affects the start-up time. Estimate τ2 by
τ2CAFB × R1 (3)
The R1 value scales vs. the VOUT option. Table 6 shows the R1
value depending on the fixed output voltage option, whereas R2
is constant at 500 kΩ. For example, at a fixed VOUT = −3.3 V, R1
equals 2.8 MΩ. To keep τ2 at a minimum, it is recommended that
CAFB be in the approximately nanofarad range. A typical setup for
the ADP7185 is CAFB = 10 nF; therefore, τ2 = 28 ms. The total
time constant, τTOTAL, is the sum of τ1 and τ2. At 2.2 × τTOTAL, VA is
equal to ~90% of the final value. Therefore, for a fixed VOUT =
−3.3 V, the output voltage is ~90% of the final value after 63.8 ms.
Table 6. R1 and R2 Values for the Fixed Output Options
Output Voltage (V) R1 (Ω) R2 (kΩ)
−1.2 700 k 500
−2.5 2 M 500
−3.3 2.8 M 500
−4.5 4 M 500
Note that τ1 and τ2 are estimates only and do not take into account
that GM and ZOUT dynamically change. It is an accurate estimate
of ~90% of the start-up time for the CAFB < 10 nF recommended
setup, where ~100% of the settling time can easily be achieved.
Note that for setups with CAFB >> 10 nF, the equation may not
hold true anymore. However, it is still a convenient estimate on
the amount of time needed to achieve ~100% of the settling time.
Data Sheet ADP7185
Rev. 0 | Page 15 of 19
APPLICATIONS INFORMATION
ADIsimPOWER DESIGN TOOL
The ADIsimPower™ design tool set supports the ADP7185.
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 in minutes. ADIsimPower can
optimize designs for cost, area, efficiency, and parts count,
taking into consideration the operating conditions and
limitations of the IC and all external components. For more
information about, and to obtain ADIsimPower design tools,
visit www.analog.com/ADIsimPower.
CAPACITOR SELECTION
Output Capacitor
The ADP7185 operates with small, space-saving ceramic
capacitors; however, it also functions with general-purpose
capacitors as long as care is taken with regard to the effective
series resistance (ESR) value. The ESR of the output capacitor
affects the stability of the LDO regulator control loop. A
minimum of 4.7 μF capacitance with an ESR of 0.05 Ω or less is
recommended to ensure the stability of the ADP7185. Output
capacitance affects the transient response to changes in load
currents. Using a larger value for the output capacitance improves
the transient response of the ADP7185 to large changes in load
current. Figure 46 shows the transient response for an output
capacitance value (COUT) of 4.7 μF.
CH1 –475mA
500mA/DIV
CH2 5.0mV
9.9mV
10.0µs/DIV
2MS 20GS/s
STOP –220mA
EDGE POSITIVE
2
1
13932-246
I
LOAD
V
OUT
Figure 46. Output Transient Response, COUT = 4.7 F, VOUT = −1.2 V
Input Bypass Capacitor
Connecting a 4.7 μF or greater capacitor from VIN to GND
reduces the circuit sensitivity to the PCB layout, especially when
long input traces or high source impedance are encountered.
When more than 4.7 μF of output capacitance is required,
increase the input capacitance to match it.
CA and CAFB Capacitors
The ultralow output noise of the ADP7185 is achieved by
keeping the LDO error amplifier in unity gain and setting the
reference voltage equal to the output voltage. In this architecture,
the resistor driven by the GM amplifier adjusts the reference
voltage to the selected output voltage. To ensure the GM amplifier
stability, the CA capacitor is needed to generate the dominant
pole and to keep the GM amplifier stable across all conditions.
CA also serves as a dampening capacitor to the inputs of the
LDO error amplifier for improved PSRR. However, the LDO
output noise scales by the GM amplifier amount of gain as a
function of the output voltage. To minimize the output voltage
noise contributed by the GM amplifier, the CAFB capacitor must
be connected between the VA and VAFB pins to keep the ac
gain of the GM amplifier in unity.
REFERENCE G
M
VA
VAFB
GND
C
AFB
C
A
R2
R1
13932-200
Figure 47. CA and CAFB Connection to the GM Amplifier
Input and Output Capacitor Properties
Any good quality ceramic capacitors can be used with the
ADP7185 if they meet the minimum capacitance and maximum
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 and X7R dielectrics with a
voltage rating from 6.3 V to 10 V are recommended. Due to their
poor temperature and dc bias characteristics, Y5V and Z5U
dielectrics are not recommended.
ADP7185 Data Sheet
Rev. 0 | Page 16 of 19
Figure 48 shows the change in capacitance vs. the dc bias voltage
characteristics of a 0805 case, 4.7 μF, 10 V, X5R capacitor. The
capacitor size and voltage ratings strongly influence the voltage
stability of a capacitor. In general, a capacitor in a larger package
or with a higher voltage rating exhibits improved stability. The
temperature variation of the X5R dielectric is about ±15% over
the −55°C to +85°C temperature range and is not a function of
package size or voltage rating.
0
024681012
CHANGE IN CAPACITANCE (µF)
DC BIAS VOLTAGE (V dc)
5.64
4.70
1.88
2.82
3.76
0.94
13932-052
Figure 48. Change in Capacitance vs. DC Bias Voltage
Use Equation 4 to determine the worst-case capacitance,
accounting for capacitor variation over temperature, component
tolerance, and voltage.
CEFF = COUT × (1 − TEMPCO) × (1 − TOL) (4)
where:
CEFF is the effective capacitance at the operating voltage.
COUT is the output capacitor.
TEMPCO is the worst-case capacitor temperature coefficient.
TOL is the worst-case component tolerance.
In this example, the worst-case temperature coefficient
(TEMPCO) over −55°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 COUT = 4.7 μF at 1.0 V.
Substituting these values in Equation 4 yields
CEFF = 4.7 μF × (1 − 0.15) × (1 − 0.1) = 3.6 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.
To guarantee the performance of the ADP7185, it is imperative
to evaluate the effects of dc bias, temperature, and tolerances on
the behavior of the capacitors for each application.
UNDERVOLTAGE LOCKOUT (UVLO)
The UVLO circuitry protects the system from power supply
brownouts. If the input voltage on VIN is more positive than
the minimum −1.58 V UVLO falling threshold, the LDO output
shuts down. The LDO enables again when the voltage to VIN is
more negative than the maximum −1.77 V UVLO rising threshold.
A typical hysteresis of 90 mV within the UVLO circuitry prevents
the device from oscillating due to the noises from VIN.
13932-053
0.05
0
–0.55
–1.60
VOUT (V)
VIN (V)
–1.74 –1.72 –1.70 –1.68 –1.66 –1.64 –1.62
–0.50
–0.45
–0.40
–0.35
–0.30
–0.25
–0.20
–0.15
–0.10
–0.05
Figure 49. Typical UVLO Behavior, VOUT = −0.5 V
CURRENT-LIMIT AND THERMAL OVERLOAD
PROTECTION
The ADP7185 is protected against damage due to excessive
power dissipation by current-limit and thermal overload
protection circuits. The ADP7185 is designed to reach current
limit when the output load reaches −900 mA (typical). When
the output load exceeds −900 mA, the output voltage is reduced
to maintain a constant current limit.
Thermal overload protection is included, which limits the
junction temperature to a maximum of 150°C (typical). Under
extreme conditions (that is, high ambient temperature and
power dissipation) when the junction temperature begins to rise
above 150°C, the output is turned off, reducing the output
current to zero. When the junction temperature drops below
135°C (typical), the output is turned on again, and the output
current is restored to its nominal value.
Consider the case where a hard short from VOUT to GND occurs.
At first, the ADP7185 reaches current limit so that only −900 mA
is conducted into the short. If self-heating of the junction becomes
great enough to cause its temperature to rise above 150°C, thermal
shutdown activates, turning off the output and reducing the
output current to zero. As the junction temperature 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 A
that continues as long as the short remains at the output. Current-
limit and thermal overload protections protect the device
against accidental overload conditions. For reliable operation,
externally limit device power dissipation so that junction
temperatures do not exceed 125°C.
Data Sheet ADP7185
Rev. 0 | Page 17 of 19
THERMAL CONSIDERATIONS
In applications with a low input to output voltage differential,
the ADP7185 does not dissipate much heat. However, in
applications with high ambient temperature and/or high input
voltage, the heat dissipated in the package may become large
enough to cause the junction temperature of the die to exceed
the maximum junction temperature of 125°C.
When the junction temperature exceeds 150°C, the converter
enters thermal shutdown. The converter 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
conditions. 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 5.
To guarantee reliable operation, the junction temperature of the
ADP7185 must not exceed 125°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 VIN pins to the PCB.
Table 7 shows the typical θJA values for the 8-lead LFCSP
package and for various PCB copper sizes.
Table 7. Typical θJA Values
Copper Size (mm2) θJA (°C/W), 8-Lead LFCSP
25 146.6
100 105.4
500 75.38
1000 65.16
6400 53.5
Calculate the junction temperatures of the ADP7185 by
TJ = TA + (PD × θJA) (5)
where:
TA is the ambient temperature.
PD is the power dissipation in the die, given by
PD = ((VINVOUT) × ILOAD) + (VIN × IGND) (6)
where:
VIN and VOUT are the input and output voltages, respectively.
ILOAD is the load current.
IGND is the ground current.
Power dissipation due to ground current is quite small and can
be ignored. Therefore, the junction temperature equation
simplifies to
TJ = TA + (((VINVOUT) × ILOAD) × θJA) (7)
As shown in Equation 7, 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 125°C.
Figure 50 to Figure 52 show the junction temperature calculations
for the different ambient temperatures, power dissipation, and
areas of the PCB copper.
13932-054
140
0
20
40
60
100
80
120
02.52.01.51.00.5
JUNCTION TEMPERATUREC)
POWER DISSIPATION (W)
T
J
MAX
6400mm
2
1000mm
2
500mm
2
100mm
2
25mm
2
Figure 50. Junction Temperature vs. Total Power Dissipation, TA = −25°C
13932-055
02.52.01.51.00.5
140
0
20
40
60
100
80
120
JUNCTION TEMPERATUREC)
POWER DISSIPATION (W)
T
J
MAX
6400mm
2
1000mm
2
500mm
2
100mm
2
25mm
2
Figure 51. Junction Temperature vs. Total Power Dissipation, TA = −50°C
13932-056
02.52.01.51.00.5
140
0
20
40
60
100
80
120
JUNCTION TEMPERATUREC)
POWER DISSIPATION (W)
T
J
MAX
6400mm
2
1000mm
2
500mm
2
100mm
2
25mm
2
Figure 52. Junction Temperature vs. Total Power Dissipation, TA = −85°C
ADP7185 Data Sheet
Rev. 0 | Page 18 of 19
PCB LAYOUT CONSIDERATIONS
Place the input capacitor (CIN) as close as possible to the VIN
and GND pins. Place the output capacitor (COUT) as close as
possible to the VOUT and GND pins. Place bypass capacitors
(CA and CREG) close to their respective pins (VA and VREG) and
GND. Use of 0805 or 0603 size capacitors and resistors achieves
the smallest possible footprint solution on boards where area is
limited. Connect the exposed pad to VIN.
13932-058
Figure 53. Evaluation Board
13932-059
Figure 54. Typical Board Layout, Top Side
13932-060
Figure 55. Typical Board Layout, Bottom Side
Data Sheet ADP7185
Rev. 0 | Page 19 of 19
OUTLINE DIMENSIONS
1.60
1.50
1.40
0.30
0.25
0.20
TOP VIEW
SIDE VIEW
8
1
5
4
0.30
0.25
0.20
BOTTOM VIEW
PIN 1 INDEX
AREA
0.60
0.55
0.50
1.10
1.00
0.90
0.152 REF
0.05 MAX
0.02 NOM
0.50 BSC
EXPOSED
PAD
FOR PROPER CONNECTION OF
THE EXPOSED PAD, REFER TO
THE PIN CONFIGURATION AND
FUNCTION DESCRIPTIONS
SECTION OF THIS DATA SHEET.
08-24-2016-A
PKG-004752
2.10
2.00 SQ
1.90
SEATING
PLANE
PIN 1
INDICATOR AREA OPTIONS
(SEE DETAIL A)
DETAIL A
(JEDEC 95)
Figure 56. 8-Lead Lead Frame Chip Scale Package [LFCSP]
2 mm × 2 mm Body and 0.55 mm Package Height
(CP-8-27)
Dimensions shown in millimeters
ORDERING GUIDE
Model1 Temperature Range Output Voltage (V)2 Package Description Package Option Branding
ADP7185ACPZN0.5-R7 −40°C to +125°C −0.5 8-Lead LFCSP CP-8-27 LTS
ADP7185ACPZN1.0-R7 −40°C to +125°C −1.0 8-Lead LFCSP CP-8-27 LTT
ADP7185ACPZN1.2-R7 −40°C to +125°C −1.2 8-Lead LFCSP CP-8-27 LTU
ADP7185ACPZN1.5-R7 −40°C to +125°C −1.5 8-Lead LFCSP CP-8-27 LTV
ADP7185ACPZN1.8-R7 −40°C to +125°C −1.8 8-Lead LFCSP CP-8-27 LTW
ADP7185ACPZN2.0-R7 −40°C to +125°C −2.0 8-Lead LFCSP CP-8-27 LTX
ADP7185ACPZN2.5-R7 −40°C to +125°C −2.5 8-Lead LFCSP CP-8-27 LTY
ADP7185ACPZN3.0-R7 −40°C to +125°C −3.0 8-Lead LFCSP CP-8-27 LTZ
ADP7185ACPZN3.3-R7 −40°C to +125°C −3.3 8-Lead LFCSP CP-8-27 LU0
ADP7185ACPZN-R7 −40°C to +125°C Adjustable 8-Lead LFCSP CP-8-27 LU1
ADP7185-3.3-EVALZ −3.3 Evaluation Board for the
Fixed Voltage Option
ADP7185-ADJ-EVALZ −2.5 Evaluation Board for the
Adjustable Voltage Option
1 Z = RoHS Compliant Part.
2 For additional voltage options, contact a local Analog Devices Inc., sales or distribution representative.
©2017 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D13932-0-5/17(0)