SC1543 Datasheet, PDF (1/5 Pages) Semtech Corporation – 400mA/200mA Dual 3.3V Smart Power Switch

400mA/200mA Dual 3.3V Smart
Power Switch
SC1543
PRELIMINARY - October 9, 2000
TEL:[phone] FAX:[phone] WEB:http://www.semtech.com
DESCRIPTION
FEATURES
The SC1543 provides a glitch free 3.3V output when
one of two 3.3V input sources is present. It does not
require external logic to sequence from one input
source to the other. Whenever VIN1 exceeds a
predetermined threshold value the internal MOSFET
connects it’s source voltage to the output. If the input at
VIN1 is below the threshold another internal MOSFET
connects VIN2 to the output. If both inputs are at 3.3V
then VIN1 will be connected to the output.
The SC1543 is designed to provide 400mA from the
main input (VIN1) and 200mA from the secondary input
(VIN2). A very low quiescent current of 10µA in
shutdown mode reduces power dissipation.
The internal logic and control circuit detects the voltage
levels of VIN1 and VIN2, and compares them to an
input reference voltage of 2.9V. An internally controlled
period of switch overlap ensures that the transition
between supplies is as glitch-free as possible.
The SC1543 is available in an MSOP-8 surface mount
package.
•= Glitch free transitions between inputs
•= Internal logic selects appropriate input
•= 400mA load current capability from main input
•= Low power shutdown mode
•= Industrial temperature range
APPLICATIONS
•= Mini PCI cards
•= Peripheral cards
•= Instantly available personal computers (IAPCs)
ORDERING INFORMATION
Part Number⁽¹⁾
Package
SC1543IMSTR
MSOP-8
Note:
(1) Only available in tape and reel packaging. A reel
contains 2500 devices.
APPLICATION CIRCUIT
SHUTDOWN
3.3V IN
3.3VAUX IN
CIN1
1uF
CIN2
1uF
U1
1 _{VIN1 SHDN} 8
2 _{VIN1 VOUT} 7
3 _{VIN2 VOUT} 6
4
5
VIN2 GND
SC1543
3.3V OUT
COUT
10uF
© 2000 SEMTECH CORP.
1
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