SC1175_04 Datasheet, PDF (1/23 Pages) Semtech Corporation – Low Power Dual Synchronous DC/DC Controller With Current Sharing Circuitry

SC1175
Low Power Dual Synchronous DC/DC
Controller With Current Sharing Circuitry
POWER MANAGEMENT
Description
The SC1175 is a versatile 2 phase, synchronous, volt-
age mode PWM controller that may be used in two dis-
tinct ways. First, the SC1175 is ideal for applications
where point of use output power exceeds any single in-
put power budget. Alternatively, the SC1175 can be used
as a dual switcher. The SC1175 features a temperature
compensated voltage reference, over current protection
with 50% fold-back and internal level-shifted, high-side
drive circuitry.
Features
‹ 300kHz fixed frequency operation
‹ Soft Start and Enable function
‹ Power Good output provided
‹ Over current protection with 50% fold-back
‹ Phase-shifted switchers minimize ripple
‹ High efficiency operation, >90%
‹ Programmable output(s) as low as 1.25V
‹ Industrial temperature range
‹ 20 pin SOIC or TSSOP package
In current sharing configuration, the SC1175 can pro-
duce a single output voltage from two separate voltage
sources (which can be different voltage levels) while
maintaining current sharing between the channels. Cur-
rent sharing is programmable to allow loading each input
supply as required by the application.
In dual switcher configuration, two feedback paths are
provided for independent control of the separate out-
puts. The device will provide a regulated output from
flexibly configured inputs (3.3V, 5V, 12V), provided 5V is
present for V_CC. The two switchers are 180° out of phase
to minimize input and output ripple.
Two Phase, Current Sharing Controller
‹ Flexible, same or separate V_IN
‹ Programmable current sharing
‹ Combined current limit with fold-back
‹ 2 phases operating opposed for ripple reduction
‹ Thermal distribution via multi-phase output
Two Independent PWM Controllers
‹
‹
Flexible, same or separate V_IN
Independent control for each channel
‹ Independent and separate current limit
‹ 2 phases operating opposed for ripple reduction (if
same V_IN used)
Applications
‹ Graphics cards
‹ DDR Memory
‹ Peripheral add-in card
‹ SSTL Termination
‹ Dual-Phase power supply
‹ Power supplies requiring two outputs
Revision: September 22, 2004
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