SC1534 Datasheet, PDF (1/7 Pages) Semtech Corporation – 400mA SmartLDOTM

400mA SmartLDO^TM
SC1534
PRELIMINARY - July 26, 2000
TEL:[phone] FAX:[phone] WEB:http://www.semtech.com
DESCRIPTION
FEATURES
The SC1534 is designed to maintain a glitch-free 3.3V
output when at least one of two inputs, 5V (VIN) and
3.3V (VAUX), is present.
Whenever VIN exceeds a predetermined threshold
value, the internal 3.3V linear regulator is enabled, and
DR is pulled high.
When VIN falls below a lower threshold value, DR is
pulled low and the internal linear regulator is turned off.
DR has been designed to drive the gate of an external
low threshold P-channel MOSFET, which can be used
to connect the 3.3V supply directly to the regulator out-
put. This ensures an uninterrupted 3.3V output even if
VIN falls out of specification. A maximum R_DS(ON) of
200mΩ is recommended.
When both supplies are simultaneously available, the
drive pin (DR) will be pulled High, turning off the exter-
nal PMOS switch.
The internal 5V detector has its upper threshold (for
VIN rising) set to 4.22V (typical) while the lower thresh-
old (for VIN falling) is at 4.05V (typical) giving a hys-
teresis of approximately 170mV.
The SC1534 is available in the popular SO-8 and 5-
lead TO-263 surface mount packages.
BLOCK DIAGRAM
PIN CONFIGURATION
Top View
SO-8
TO-263-5L
•= Glitch-free transition between input sources
•= Internal logic selects input source
•= Gate drive for external PMOS bypass switch
•= 5V detector with hysteresis
•= 1% regulated output voltage accuracy
•= 400mA load current capability
•= SO-8 and TO-263 packages
APPLICATIONS
•= Desktop Computers
•= Network Interface Cards (NICs)
•= PCMCIA/PCI Interface Cards
•= Cardbus^TM Technology
•= Power supplies with multiple input sources
ORDERING INFORMATION
Part Number⁽¹⁾
Package
SC1534CM.TR
TO-263-5L
SC1534CS.TR
SO-8
Note:
(1) Only available in tape and reel packaging.
ABSOLUTE MAXIMUM RATINGS
Parameter
Symbol Maximum Units
Input Supply Voltage
VIN -0.5 to +7 V
Auxiliary Supply Voltage VAUX -0.5 to +7 V
LDO Output Current
Operating Ambient
Temperature Range
I_O
10 to 400 mA
T_A
-5 to +70 °C
Operating Junction
Temperature Range
T_J
-5 to +125 °C
Storage Temperature
Range
T_STG -65 to +150 °C
Lead Temperature
(Soldering) 10 Sec
T_LEAD
300
°C
Thermal Impedance
Junction to Ambient
SO-8⁽¹⁾
θ_JA
65
°C/W
TO-263
60
Thermal Impedance
Junction to Case
SO-8
θ_{J C}
39
°C/W
TO-263
3
ESD Rating
ESD
2
kV
Note:
(1) 1 inch square of 1/16” FR-4, double sided, 1 oz. mini-
mum copper weight.
1
© 2000 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320