SI786 Datasheet, PDF (1/14 Pages) Vishay Siliconix – Dual-Output Power-Supply Controller

Si786
Vishay Siliconix
Dual-Output Power-Supply Controller
FEATURES
D Fixed 5-V and 3.3-V Step-down Converters
D Less than 500-mA Quiescent Current per Converter
D 25-mA Shutdown Current
D 5.5-V to 30-V Operating Range
DESCRIPTION
The Si786 Dual Controller for Portable Computer Power
Conversion is pin and functionally compatible with the
MAX786 dual-output power supply controller for notebook
computers. The device is designed as a drop-in replacement
for that circuit.
The circuit is a system level integration of two step-down
controllers, micropower 5-V and 3.3-V linear regulators, and
two comparators. The controllers perform high efficiency
conversion of the battery pack energy (typically 12 V) or the
output of an ac to dc wall converter (typically 18-V to 24-V dc)
to 5-V and 3.3-V system supply voltages. The micropower
linear regulator can be used to keep power management and
back-up circuitry alive during the shutdown of the step-down
converters. The comparators can be biased at any voltage
between 2.7 V and the input voltage, simplifying battery
monitoring or providing sufficient voltage to enhance the gate
of a low on-resistance n-channel FET used in switching power
to different zones in the system.
A complete power conversion and management system can
be implemented with the Si786 Dual Controller for Portable
Computer Power Conversion, an inexpensive linear regulator,
the Si9140 SMP Controller for High Performance Processor
Power Supplies, five Si4410 n-channel TrenchFETR Power
MOSFETs, one Si4435 p-channel TrenchFET Power
MOSFET, and two Si9712 PC Card (PCMCIA) Interface
Switches.
The Si9130 Pin-Programmable Dual Controller for Portable
PCs is another integrated system level devices for portable PC
power systems.
The Si786 is available in both standard and lead (Pb)-free
28-pin SSOP packages and specified to operate over the (0_C
to 70_C), (−10_C to 90_C) and (−40_C to 85_C) temperature
ranges. See Ordering Information for corresponding part
numbers.
FUNCTIONAL BLOCK DIAGRAM
5.5. V
to
30 V
SHUTDOWN
5-V ON/OFF
3.3-V ON/OFF
SYNC
Document Number: 70189
S-40807—Rev. J, 26-Apr-04
Si786
Power
Section
3.3 V
5V
mP
Memory
Peripherals
Low-Battery Warning
Power-Good
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