YB1200R
150mA High PSRR with Auto-Discharge LDO Regulator
Functional Block Diagram
Functional Description
The YB1200R is an ultra-low-noise,
low-quiescent current, low-dropout linear
regulator. It is supplied in a extremely small
SC-70 / SC82 package for different
applications. YB1200R can supply loads up
to 150mA (typical operation, not maximum)
and output voltages are preset and ranging
from 1.2V to 3.6V.
As shown in the
Functional Block Diagram,
the YB1200R consists of a reference and
noise bypass circuit, error amplifier, output
drive transistor, internal feedback voltage
divider, thermal sensor, and short circuit
current limiter.
The internal reference is connected to the
error amplifier’s inverting input. The error
amplifier compares this reference with the
feedback voltage and amplifies the
difference. If the feedback voltage is lower
YB1200R MRev. 1.0
than the reference voltage, the gate of the
pass-transistor is pulled low. This allows
more current to pass to the output and
increases the output voltage. If the
feedback voltage is too high, the gate of the
pass transistor is pulled high, allowing less
current to pass to the output.
Stability
The YB1200R is a high performance LDO
emphasizing stability with low output
capacitance. It is able to maintain stability
with an output capacitor as low as 0.47 uF.
The output capacitor can also be increased
to optimize performance. The YB1200R will
remain stable and in regulation with no load,
unlike many other voltage regulators.
Internal P-Channel Pass Transistor
The YB1200R features a low impedance
8
www.yobon.com.tw
YOBON [ YOBON TECHNOLOGIES,INC. ]
