−500 mA, Ultralow Noise, High PSRR,
Low Dropout Linear Regulator
ADP7185
Data Sheet
FEATURES
TYPICAL APPLICATION CIRCUITS
Input voltage range: −2.0 V to −5.5 V
Maximum output current: −500 mA
EP
V
= –3.8V
VIN
VOUT
V
= –3.3V
IN
OUT
C
4.7µF
C
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
IN
OUT
4.7µF
SENSE
ADP7185
+1.25V
0V
VA
C
1µF
C
OFF
EN
A
AFB
10nF
–1.3V
ON
VAFB
VREG
GND
68 dB at 10 kHz
50 dB at 100 kHz
C
REG
1µF
40 dB at 1 MHz
Figure 1. ADP7185 with Fixed Output Voltage, −3.3 V
Low dropout voltage: −190 mV typical at −500 mA load
Initial output voltage (VOUT) accuracy: 0.5ꢀ
Output voltage accuracy over line, load, and temperature:
2.2ꢀ
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
EP
V
= –3V
OFF
VIN
EN
VOUT
V
= –2.5V
IN
OUT
C
4.7µF
C
IN
OUT
4.7µF
SENSE
ADP7185
+1.25V
0V
VA
R1
100kΩ
C
A
1µF
C
AFB
10nF
–1.3V
ON
VAFB
R2
24.9kΩ
Current-limit and thermal overload protection
8-lead, 2 mm × 2 mm LFCSP package
Supported by ADIsimPOWER voltage regulator design tool
VREG
GND
C
REG
1µF
Figure 2. ADP7185 with Adjustable Output Voltage, VOUT = −2.5 V
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
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.
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.
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.
Rev. 0
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