50 mA, High Voltage,
Micropower Linear Regulator
ADP1720
Rev. A
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FEATURES
Wide input voltage range: 4 V to 28 V
Maximum output current: 50 mA
Low light load current:
28 μA at 0 μA load
35 μA at 100 μA load
Low shutdown current: 0.7 μA
Low dropout voltage: 275 mV @ 50 mA load
Initial accuracy: ±0.5%
Accuracy over line, load, and temperature: ±2%
Stable with small 1μF ceramic output capacitor
Fixed 3.3 V and 5.0 V output voltage options
Adjustable output voltage option: 1.225 V to 5.0 V
Current limit and thermal overload protection
Logic controlled enable
Space-saving thermally enhanced MSOP package
APPLICATIONS
DC-to-DC post regulation
PCMCIA regulation
Keep-alive power in portable equipment
Industrial applications
TYPICAL APPLICATION CIRCUITS
GND
1 8
GND
2
GND
3
GND
4
7
6
GND
IN
OUT
EN
5
ADP1720
FIXED
V
IN
= 28V
OUT
= 5V
1µF
1µF
06111-001
Figure 1. ADP1720 with Fixed Output Voltage, 5.0 V
GND
1
GND
2
GND
3
GND
4
8
7
6
ADJ
IN
OUT
EN
5
ADP1720
ADJUSTABLE
V
IN
= 12V
V
OUT
=
1.225V(1 + R1/R2)
1µF
1µF
R1
R2
06111-002
Figure 2. ADP1720 with Adjustable Output Voltage, 1.225 V to 5.0 V
GENERAL DESCRIPTION
The ADP1720 is a high voltage, micropower, low dropout linear
regulator. Operating over a very wide input voltage range of 4 V
to 28 V, the ADP1720 can provide up to 50 mA of output current.
With just 28 μA of quiescent supply current and a micropower
shutdown mode, this device is ideal for applications that require
low quiescent current.
The ADP1720 is available in fixed output voltages of 3.3 V and
5.0 V. An adjustable version is also available, which allows the
output to be set anywhere between 1.225 V and 5.0 V. An enable
function that allows external circuits to turn on and turn off the
ADP1720 output is available. For automatic startup, the enable
(EN) pin can be connected directly to the input rail.
The ADP1720 is optimized for stable operation with small 1 μF
ceramic output capacitors, allowing for good transient perform-
ance while occupying minimal board space.
The ADP1720 operates from –40°C to +125°C and uses current
limit protection and thermal overload protection circuits to
prevent damage to the device in adverse conditions.
Available in a small thermally enhanced MSOP package, the
ADP1720 provides a compact solution with low thermal resistance.
