ADP130 Analog Devices, ADP130 Datasheet - Page 12

• Manufacturer Part Number: ADP130
• Description: 350 mA, Low VIN, Low Quiescent Current, CMOS Linear Regulator
• Manufacturer: Analog Devices

THEORY OF OPERATION
The ADP130 is a low dropout, linear regulator that uses an
advanced proprietary architecture to achieve low quiescent
current and high efficiency regulation. It also provides high
power supply rejection ratio (PSRR) and excellent line and load
transient response using a small 1 µF ceramic output capacitor. The
device operates from a 2.3 V to 5.5 V bias rail and a 1.2 V to 3.6 V
input rail to provide up to 350 mA of output current. Supply
current in shutdown mode is typically less than 1 µA.
Internally, the ADP130 consists of a reference, an error ampli-
fier, a feedback voltage divider, and a pass device. The output
current is delivered via the pass device, which is controlled by
the error amplifier, forming a negative feedback system that
ideally drives the feedback voltage to equal the reference voltage.
If the feedback voltage is lower than the reference voltage, the
negative feedback drives more current, increasing the output
voltage. If the feedback voltage is higher than the reference voltage,
the negative feedback drives less current, decreasing the output
voltage. The VBIAS pin is the positive supply for all circuitry
except the pass device.
ADP130
Rev. B | Page 12 of 20
The ADP130 has an internal soft start that limits the output
voltage ramp period to approximately 200 µs. All internal devices
are controlled by the enable pin, EN. When EN is high, the
output is on; when EN is low, the output is off.
The ADP130 is available in output voltages ranging from 0.8 V to
3.0 V. The ADP130 uses the EN pin to enable and disable the
VOUT pin under normal operating conditions. When EN is
high, VOUT turns on. When EN is low, VOUT turns off. For auto-
matic startup, EN can be tied to VBIAS.
GND
VIN
EN
SHORT-CIRCUIT,
SHUTDOWN
UVLO, AND
THERMAL
PROTECT
Figure 33. Internal Block Diagram
0.5V
REF
R1
R2
VOUT
VBIAS