ADP151(Rev0) 데이터 시트보기 (PDF) - Analog Devices
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ADP151 Datasheet PDF : 24 Pages
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THEORY OF OPERATION
The ADP151 is an ultralow noise, low quiescent current, low
dropout linear regulator that operates from 2.2 V to 5.5 V and
can provide up to 200 mA of output current. Drawing a low
265 μA of quiescent current (typical) at full load makes the
ADP151 ideal for battery-operated portable equipment. Shut-
down current consumption is typically 200 nA.
Using new innovative design techniques, the ADP151 provides
superior noise performance for noise-sensitive analog and RF
applications without the need for a noise bypass capacitor. The
ADP151 is also optimized for use with small 1 µF ceramic
capacitors.
VIN
VOUT
R1
GND
SHORT CIRCUIT,
UVLO, AND
THERMAL
PROTECT
EN
SHUTDOWN
REN
R2
REFERENCE
Figure 25. Internal Block Diagram
ADP151
Internally, the ADP151 consists of a reference, an error
amplifier, a feedback voltage divider, and a PMOS 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.
An internal pull-down resistor on the EN input holds the input
low when the pin is left open.
The ADP151 is available in 16 output voltage options, ranging
from 1.1 V to 3.3 V. The ADP151 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 automatic startup, EN can be tied to VIN.
Rev. 0 | Page 11 of 24
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