SC561 Datasheet, PDF (1/15 Pages) Semtech Corporation – Dual Output Low Noise LDO Linear Regulator

POWER MANAGEMENT
Features
„ Input voltage range — 2.5V to 5.5V
„ Output voltage — V = 3.1V; V = 2.85V
LDOA
LDOB
„ Maximum output current — 300mA (each LDO)
„ Dropout at 200mA load — 200mV max.
„ Quiescent supply current — 40μA (both LDOs
enabled)
„ Shutdown current — 100nA (typ)
„ Output noise < 50μV
RMS
„ PSRR >65dB at 1kHz
„ Over-temperature protection
„ Short-circuit protection
„ Under-voltage lockout
„ Power good monitor for output A
„ MLPQ-UT8, 1.5mm x 1.5mm x 0.6mm package
Applications
„ PDAs and cellular phones
„ GPS devices
„ Palmtop computers and handheld instruments
„ TFT/LCD applications
„ Wireless handsets
„ Digital cordless phones and PCS phones
„ Personal communicators
„ Wireless LAN
SC561
Dual Output Low Noise LDO
Linear Regulator
Description
The SC561 is a dual output, ultra-low dropout linear
voltage regulator designed for use in battery powered
applications. The SC561 provides fixed output voltages of
V = 3.1V and V = 2.85V, and up to 300mA of load
LDOA
LDOB
current per channel.
In applications where maximum battery life is essential,
the SC561 can operate in an extremely low power state by
setting the dynamic bias control. At very light loads, the
LOAD pin can be pulled low so that the device consumes
only 40μA of quiescent current.
The SC561 provides superior low-noise performance by
using an external bypass capacitor to filter the bandgap
reference. The device also has a PGOOD output to hold a
processor in reset when the voltage on OUTA is not in
regulation.
The device provides protection circuitry such as short-
circuit protection, under-voltage lockout, and thermal
protection to prevent device failures. Stability is main-
tained by using 1μF capacitors on the output pins. The
MLPQ-UT8 package and small ceramic bypass capacitors
minimize the required PCB area.
Typical Application Circuit
VIN
EN
LOAD
C_IN
2.2μF
SC561
IN
PGOOD
EN
OUTA
LOAD
OUTB
GND ^BYP
C_BYP
22nF
C_OUTA C_OUTB
1μF 1μF
PGOOD
OUTA
OUTB
November 21, 2007
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