SI91860 Datasheet, PDF (1/8 Pages) Vishay Siliconix – 400-mA Smart Regulator for Network Interface Card

Si91860
Vishay Siliconix
400-mA Smart Regulator for Network Interface Card
FEATURES
D Single Fixed 3.3-V Output
D Linear Regulator for Dual Power Inputs
D Auxilliary Input Can Be Bypassed
D Automatically Switches Between Linear Regulator
and Bypass Mode
D Linear Regulator: 3.3-V "3% Output at 400-mA
Current
D Linear Regulator: 600-mA Peak Output Current
D Low Bypass Switch Drop: <55-mV Drop at 150 mA
D Built-in Short Circuit and Thermal Shutdown
Protection
D Low Supply Current
D SOIC-8 Package
APPLICATIONS
D Network Interface Cards (NIC)
D PCMCIA Cards
D Cardbus
D Desktop Computers/Workstations
DESCRIPTION
The Si91860 provides a constant 3.3-V output with multiple
inputs. This function is required in many power interface
applications, such as the Network Interface Card (NIC). The
Si91860 is offered in small SOIC-8 package with up to 2-W
Power handling capability. The complete application circuit
uses only four external components.
The PCI Card has a 3.3-V Chipset while the PCI bus has two
independent 5-V sources. When needed, the two 5-V sources
are available from the PCI bus or directly from the
motherboard—normally 5 V_IN and standby 5 V_SB. The
internal regulator steps down from either of the 5-V supplies
to 3.3 V. A 200-mΩ power switch is integrated to connect the
3.3-V_AUX input to the output. The power drawn priority is 5 V_IN
> 5 V_SB > 3.3 V_AUX, where the selection is done internally and
automatically by the Si91860. The power handling capability
is as such as to carry at least 400-mA continuous load current
for any power input condition.
In order to satisfy the stringent ambient temperature
requirements in many applications, the Si91860 is rated for the
industrial temperature range of −40_C to 85_C.
The Si91860 is available in both standard and lead (Pb)-free
packages.
FUNCTIONAL BLOCK DIAGRAM
Si91860
5 V_SB
5 V_IN
3.3 V_AUX
Regulator
and
Control
3.3 V_OUT
GND
Document Number: 71340
S-40704—Rev. B, 19-Apr-04
www.vishay.com
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