CS5231-3 Datasheet, PDF (1/14 Pages) Cherry Semiconductor Corporation – 500mA, 3.3V Linear Regulator with Auxiliary Control

CS5231−3
500 mA, 3.3 V Linear
Regulator with Auxiliary
Control
The CS5231−3 combines a three−terminal linear regulator with
circuitry controlling an external PFET transistor thus managing two
input supplies. The part provides a 3.3 V regulated output either from
the main 5.0 V supply or a 3.3 V auxiliary that switches on when the
5.0 V supply is not present. This delivers constant, uninterrupted
power to the load. The CS5231−3 meets Intel’s “Instantly Available”
power requirements which follows from the “Advanced Configuration
and Power Interface” (ACPI) standards developed by Intel, Microsoft
and Toshiba.
The CS5231−3 linear regulator provides a fixed 3.3 V output at
500 mA with an overall accuracy of ± 2.0%. The internal NPN−PNP
composite pass transistor provides a low dropout voltage and requires
less supply current than a straight PNP design. Full protection with
both current limit and thermal shutdown is provided.
Designed for low reverse current, the IC prevents excessive current
from flowing from V_OUT to either V_IN or ground when the regulator
input voltage is lower than the output voltage.
The CS5231−3 can be used to provide power to an ASIC on a PCI
Network Interface Card (NIC). When the system enters a Sleep State
and the 5.0 V input drops below 4.4 V, the AuxDrv control signal on the
CS5231−3 is activated turning on the external PFET. This switches the
supply source from the 5.0 V input to the 3.3 V input through the PFET,
guaranteeing a constant 3.3 V output to the ASIC that is “glitch free.”
The CS5231−3 is available in two package types: the D²PAK−5
(TO263) package and the SOIC−8 4−Lead−fused (DF) package. Other
applications include desktop computers, power supplies with multiple
input sources and PCMCIA/PCI interface cards.
Features
• Linear Regulator
− 3.3 V ± 2.0% Output Voltage
− 3.0 mA Quiescent Current @ 500 mA
− Fast Transient Response
− Current Limit Protection
− Thermal Shutdown with Hysteresis
− 450 mA Reverse Output Current
• System Power Management
− Auxiliary Supply Control
− “Glitch Free” Transition Between Two Supplies
• Internally Fused Leads in SOIC−8 Package
http://onsemi.com
1
5
8
1
D²PAK−5
DP SUFFIX
CASE 936AC
SOIC−8
DF SUFFIX
CASE 751
PIN CONNECTIONS AND
MARKING DIAGRAMS
D²PAK−5
CS5231−3
AWLYWW
1
Pin 1. No Connect
2. V_IN
3. GND
4. V_OUT
5. AuxDrv
Tab = GND
1 ^SOIC−8 8
NC
AuxDrv
GND
GND
GND
GND
V_IN
V_OUT
A
= Assembly Location
WL, L = Wafer Lot
YY, Y = Year
WW, W = Work Week
ORDERING INFORMATION
Device
Package
Shipping†
CS5231−3GDP5 D²PAK−5 50 Units/Rail
CS5231−3GDPR5 D²PAK−5 750 Tape & Reel
CS5231−3GDF8 SOIC−8
95 Units/Rail
CS5231−3GDFR8 SOIC−8 2500 Tape & Reel
†For information on tape and reel specifications,
including part orientation and tape sizes, please
refer to our Tape and Reel Packaging Specifications
Brochure, BRD8011/D.
© Semiconductor Components Industries, LLC, 2004
1
January, 2004 − Rev. 5
Publication Order Number:
CS5231−3/D