SC560 Datasheet, PDF (1/15 Pages) Semtech Corporation – Dual Output Low Noise LDO Linear Regulator

SC560
Dual Output Low Noise LDO
Linear Regulator
POWER MANAGEMENT
Features
Description
„ Input voltage range — 2.5V to 5.5V
„ Output voltage ranges — 1.2V to 3.3V (each LDO)
„ Maximum output current — 300mA (both LDOs)
„ Dropout at 200mA load — 200mV max.
„ Quiescent supply current — 100μA (both LDOs
enabled)
„ Shutdown current — 100nA (typ)
„ Output noise < 50μV (SC560A and fixed output
RMS
versions)
„ PSRR < -65dB at 1kHz (SC560A and fixed output
versions)
„ Over-temperature protection
„ Short-circuit protection
„ Under-voltage lockout
„ Power good monitor for output A (SC560C and fixed
output versions)
„ Independent enable/disable for LDOB (SC560C and
fixed output versions)
„ 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
The SC560 is a family of dual output, ultra-low dropout
linear voltage regulators designed for use in battery
powered wireless applications. The SC560A, SC560B, and
SC560C provide adjustable output voltages that can be
set using two external resistors. Fixed output voltages
are also available (see ordering information for available
combinations). Fixed output devices provide the power-
good monitor, independent enable pins, and a bypass pin
for low-noise operation
All members of the SC560 family require an input voltage
level between 2.5V and 5.5V. Output voltages for the
adjustable versions can vary between 1.2V and 3.3V. Fixed
output voltage options are also chosen from this range.
The SC560A provides superior low-noise performance
by using an external bypass capacitor connected to pin
7 to filter the bandgap reference. The SC560B uses pin 7
as a separate enable pin for the second regulator output
so the two outputs can be controlled independently.
The SC560C uses this pin to provide a PGOOD output
to hold a processor in reset when the voltage on OUTA
is not in regulation. All other versions provide all three
functions with fixed output voltages (no feedback pins
are provided).
The device also provides protection circuitry such as
current limiting, under-voltage lockout, and thermal
protection to prevent device failures. Stability is
maintained by using 1μF capacitors on the output pins.
The MLPQ-UT8 package and 0402 ceramic capacitors
minimize the required PCB area.
Typical Application Circuit
VIN
EN
ENB
C_IN
2.2μF
SC560D
VIN
PGOOD
EN
OUTA
ENB
OUTB
GND ^BYP
C_BYP
22nF
C_OUTA C_OUTB
1μF 1μF
PGOOD
OUTA
OUTB
September 12, 2007
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