SC1545CS. 1545CS Datasheet

1545CS SC1545CS. Datasheet pdf. Equivalent

1545CS Datasheet
Recommendation 1545CS Datasheet
Part 1545CS
Description SC1545CS
Feature 1545CS; www.DataSheet4U.com 500mA SmartLDO With Power Up Signal Sequencing PRELIMINARY - January 17, 2000 .
Manufacture Semtech Corporation
Datasheet
Download 1545CS Datasheet




Semtech Corporation 1545CS
www.DataSheet4U.com
500mA SmartLDOTM With Power Up
Signal Sequencing
SC1545
PRELIMINARY - January 17, 2000
DESCRIPTION
TEL:805-498-2111 FAX:805-498-3804 WEB:http://www.semtech.com
FEATURES
The SC1545 was designed for instantly available moth-
erboard applications. As part of the Semtech family of
SmartLDO’s it provides additional control functions not
available in a standard LDO.
500mA LDO with Over Current Protection (OCP)
±2.5% LDO regulation over line, load and
temperature
Power sequencing for three supplies
The device provides the capability to control three sep-
arate supplies. There is an on-board 500mA, 2.5V
LDO with current limit protection, and drive pins for an
N-channel MOSFET and a P-channel MOSFET. Inter-
nal logic circuitry ensures that the system starts up in a
controlled manner, and that the correct outputs are en-
abled during specific sequences of BF_CUT and SLP.
The LDO draws its power from the 5V standby supply,
and the N-channel MOSFET drive is derived from the
12V supply.
The SC1545 is available in the surface mount SO-8
package.
APPLICATIONS
Instantly available motherboards
Embedded systems
Desktop computers
ORDERING INFORMATION
Part Number(1)
SC1545CS
Package
SO-8
Note:
(1) Add suffix ‘TR’ for tape and reel packaging.
TYPICAL APPLICATION CIRCUIT
2.5V OUT
2.5V IN
Q1
3.3V IN
Q2
C1
2 x 100uF
Si4410
C2
100uF
C3
2 x 100uF
IRLMS6802
3.3V OUT
C4
100uF
2.5V OUT
C5
10uF
U1
1 VO
2 GND
3 PDR
4
NDR
5VSTBY
12VIN
BF_CUT
SLP
8
7
6
5
SC1545
5V STANDBY
12V IN
BF_CUT
SLP
C6 C7
1uF 0.1uF
© 2000 SEMTECH CORP.
1
652 MITCHELL ROAD NEWBURY PARK CA 91320



Semtech Corporation 1545CS
www.DataSheet4U.com
500mA SmartLDOTM With Power Up
Signal Sequencing
SC1545
PRELIMINARY - January 17, 2000
ABSOLUTE MAXIMUM RATINGS
Parameter
12V Input Voltage Range
5V Input Voltage Range
P-channel MOSFET Gate Drive
N-channel MOSFET Gate Drive
Input Pins
Operating Ambient Temperature Range
Operating Junction Temperature Range
Storage Temperature Range
Lead Temperature (Soldering) 10 Sec
Thermal Impedance Junction to Case
Thermal Impedance Junction to Ambient(1)
ESD Rating
Note:
(1) 2 inch square of 1/16” FR-4, double sided, 1 oz. minimum copper weight.
Symbol
12VIN
5VSTBY
PDR
NDR
TA
TJ
TSTG
TLEAD
θJC
θJA
ESD
Maximum
-0.3 to +15
-0.3 to +7
-0.3 to 5VSTBY
-0.3 to 12VIN
-0.3 to +7
0 to +70
0 to +125
-65 to +150
300
47
65
2
Units
V
V
V
V
V
°C
°C
°C
°C
°C/W
°C/W
kV
ELECTRICAL CHARACTERISTICS
Unless specified, 12VIN = 12V, 5VSTBY = 5V, CO = 100µF min., TA = 25°C. Values in bold apply over full operating temperature range.
Parameter
Symbol
Test Conditions
MIN TYP MAX Units
12VIN
Supply Voltage
12VIN
11.28 12.00 12.72 V
Quiescent Current
IQ12
800 1000 µA
1200
5VSTBY
Supply Voltage
5VSTBY
4.7 5.0 5.3 V
Quiescent Current
IQ5
LDO ON
9.5 11
12 mA
LDO OFF
3.0 4.0
5.0
Undervoltage Lockout (5V)
UVLO Threshold
UVLO
5VSTBY rising
4.1 4.3 4.5 V
5VSTBY falling
3.9 4.1 4.3 V
Hysteresis
HYST
200 mV
Logic Reset Threshold
RST
1.5 2.0 2.5 V
© 2000 SEMTECH CORP.
2
652 MITCHELL ROAD NEWBURY PARK CA 91320



Semtech Corporation 1545CS
www.DataSheet4U.com
500mA SmartLDOTM With Power Up
Signal Sequencing
SC1545
PRELIMINARY - January 17, 2000
ELECTRICAL CHARACTERISTICS (Cont.)
Unless specified, 12VIN = 12V, 5VSTBY = 5V, CO = 100µF min., TA = 25°C. Values in bold apply over full operating temperature range.
Parameter
Symbol
Test Conditions
MIN TYP MAX Units
VO
LDO Output Voltage
VO
4.7V 5VSTBY 5.3V,
-1.5% 2.525 +1.5% V
LDO Output Voltage During
Load Transients(1)
Time To Regulation(2)
Inputs (BF_CUT & SLP)
VO(T)
tREG
1mA IO 500mA
-2.5%
+2.5%
Load step between 0mA and 500mA at -3.0% 2.525 +3.0%
8A/µs max.
5
V
µs
Input Resistance
RIN
BF_CUT = SLP = 5V
1.0 10.0
M
High Level Input Voltage
Low Level Input Voltage
NDR
VIH
VIL
2.0 V
0.8 V
Peak Drive Current
INDR(PK)
Sinking: NDR = 0.5V
Sourcing: NDR = 10V
30
mA
Output Voltage
Drive Low Delay
VNDR
tDL(N)
Full ON, INDR = 100µA
10 12
V
Measured from BF_CUT threshold to
90% of NDR
150 ns
Fall Time
Drive High Delay
tf(N)
tDH(N)
Measured from 90% to 10%
Measured from BF_CUT/SLP threshold
to 10% of NDR
1.0 µs
300 ns
Rise Time
PDR
tr(N) Measured from 10% to 90%
1.0 µs
Peak Drive Current
IPDR(PK)
Sinking: PDR = 0.5V
Sourcing: PDR = 3.5V
30
mA
Output Voltage
Drive Low Delay
VPDR
tDL(P)
Full ON, IPDR = 100µA
3.5 5
V
Measured from BF_CUT threshold to
90% of PDR
150 ns
Fall Time
Drive High Delay
tf(P)
tDH(P)
Measured from 90% to 10%
Measured from BF_CUT/SLP threshold
to 10% of PDR
1.0 µs
300 ns
Rise Time
tr(P) Measured from 10% to 90%
Overcurrent Protection
1.0 µs
Current Limit Threshold
ICL
VO = 0V 550 mA
NOTES:
(1) The LDO will bring the output back to within the regular VO limits in less than 10µs.
(2) External 2.5V ± 2.5% applied at output, turning off when NDR goes low. CO = 100µF to 400µF, IO = 50mA to
200mA.
3
© 2000 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320







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