SC1458 Datasheet, PDF (1/13 Pages) Semtech Corporation – Dual Output Low Noise LDO Linear Regulator

POWER MANAGEMENT
Features
„ Input voltage range — 2.5 to 5.5V
„ Output voltages — 2.8V and 1.8V (SC1458A), 2.85V
and 2.85V (SC1458B)
„ Maximum output current — 300mA (each LDO)
„ Low 200mV maximum dropout at 200mA load
„ Quiescent current — 100μA (both LDOs enabled)
„ Shutdown current — 100nA
„ Output noise < 50μV (SC1458B)
RMS
„ PSRR > 65dB at 1kHz (SC1458B)
„ Space saving package — MLPD-W6, 3mm x 3mm
„ Over-temperature protection
„ Short-circuit protection
„ Under-voltage lockout
„ Reset monitor for output A (SC1458A)
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
„ Two-way pagers
„ Wireless LAN
SC1458
Dual Output Low Noise LDO
Linear Regulator
Description
The SC1458 is a family of dual output, ultra-low dropout
linear voltage regulators designed for use in battery
powered wireless applications. Both versions of the
SC1458 require an input voltage level between 2.5V and
5.5V. The SC1458A supplies 2.5V on OUTA and 1.8V on
OUTB, while SC1458B supplies 2.85V on both outputs.
(For other voltage options see the SC560).
The SC1458A provides a PGOOD output to hold a processor
in reset when the voltage on OUTA is not in regulation.
The SC1458B provides superior low-noise performance by
using an external bypass capacitor to filter the bandgap
reference. Both versions have a single enable pin that
controls both LDO outputs. The startup sequence delays
the start of OUTB by 128μs after OUTA is enabled.
Each version 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 MLPD package and 0402 ceramic capacitors minimize
the required PCB area.
Typical Application Circuit
VIN
From μP
C_IN
2.2μF
September 12, 2007
SC1458A
VIN
PGOOD
EN
OUTA
GND
OUTB
C_OUTA
1μF
C_OUTB
1μF
To μP
OUTA
2.5V, 300mA
OUTB
1.8V, 300mA
1