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1545CS Dataheets PDF



Part Number 1545CS
Manufacturers Semtech Corporation
Logo Semtech Corporation
Description SC1545CS
Datasheet 1545CS Datasheet1545CS Datasheet (PDF)

www.DataSheet4U.com 500mA SmartLDO With Power Up Signal Sequencing PRELIMINARY - January 17, 2000 TM SC1545 TEL:805-498-2111 FAX:805-498-3804 WEB:http://www.semtech.com DESCRIPTION The SC1545 was designed for instantly available motherboard applications. As part of the Semtech family of SmartLDO’s it provides additional control functions not available in a standard LDO. The device provides the capability to control three separate supplies. There is an on-board 500mA, 2.5V LDO with current l.

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www.DataSheet4U.com 500mA SmartLDO With Power Up Signal Sequencing PRELIMINARY - January 17, 2000 TM SC1545 TEL:805-498-2111 FAX:805-498-3804 WEB:http://www.semtech.com DESCRIPTION The SC1545 was designed for instantly available motherboard applications. As part of the Semtech family of SmartLDO’s it provides additional control functions not available in a standard LDO. The device provides the capability to control three separate 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. Internal logic circuitry ensures that the system starts up in a controlled manner, and that the correct outputs are enabled 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. FEATURES • • • 500mA LDO with Over Current Protection (OCP) ±2.5% LDO regulation over line, load and temperature Power sequencing for three supplies APPLICATIONS • • • Instantly available motherboards Embedded systems Desktop computers ORDERING INFORMATION Part Number SC1545CS (1) Package SO-8 Note: (1) Add suffix ‘TR’ for tape and reel packaging. TYPICAL APPLICATION CIRCUIT 2.5V IN Q1 2.5V OUT Si4410 C1 2 x 100uF C2 100uF 3.3V IN Q2 3.3V OUT IRLMS6802 C3 2 x 100uF C4 100uF U1 1 2.5V OUT 2 3 4 C5 10uF VO GND PDR NDR SC1545 5VSTBY 12VIN BF_CUT SLP 8 7 6 5 C6 1uF C7 0.1uF 5V STANDBY 12V IN BF_CUT SLP 1 © 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 www.DataSheet4U.com 500mA SmartLDO With Power Up Signal Sequencing PRELIMINARY - January 17, 2000 TM SC1545 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 ESD Rating Note: (1) 2 inch square of 1/16” FR-4, double sided, 1 oz. minimum copper weight. (1) Symbol 12VIN 5VSTBY PDR NDR Maximum -0.3 to +15 -0.3 to +7 -0.3 to 5VSTBY -0.3 to 12VIN -0.3 to +7 Units V V V V V °C °C °C °C °C/W °C/W kV TA TJ TSTG TLEAD θJC θJA ESD 0 to +70 0 to +125 -65 to +150 300 47 65 2 ELECTRICAL CHARACTERISTICS Unless specified, 12VIN = 12V, 5VSTBY = 5V, CO = 100µF min., TA = 25°C. Values in bold apply over full operating temperature range. Parameter 12VIN Supply Voltage Quiescent Current Symbol Test Conditions MIN TYP MAX Units 12VIN IQ12 11.28 12.00 12.72 800 1000 1200 V µA 5VSTBY Supply Voltage Quiescent Current 5VSTBY IQ5 LDO ON 4.7 5.0 9.5 5.3 11 12 LDO OFF 3.0 4.0 5.0 Undervoltage Lockout (5V) UVLO Threshold UVLO 5VSTBY rising 5VSTBY falling Hysteresis Logic Reset Threshold HYST RST 1.5 4.1 3.9 4.3 4.1 200 2.0 2.5 4.5 4.3 V V mV V mA V 2 © 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 www.DataSheet4U.com 500mA SmartLDO With Power Up Signal Sequencing PRELIMINARY - January 17, 2000 TM SC1545 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 VO LDO Output Voltage Symbol Test Conditions 4.7V ≤ 5VSTBY ≤ 5.3V, 1mA ≤ IO ≤ 500mA MIN TYP MAX Units VO -1.5% 2.525 +1.5% -2.5% +2.5% V LDO Output Voltage During (1) Load Transients Time To Regulation (2) VO(T) tREG RIN VIH VIL INDR(PK) VNDR tDL(N) tf(N) tDH(N) tr(N) IPDR(PK) VPDR tDL(P) tf(P) tDH(P) tr(P) ICL Load step between 0mA and 500mA at 8A/µs max. -3.0% 2.525 +3.0% 5 V µs MΩ V Inputs (BF_CUT & SLP) Input Resistance High Level Input Voltage Low Level Input Voltage NDR Peak Drive Current Output Voltage Drive Low Delay Fall Time Drive High Delay Rise Time PDR Peak Drive Current Output Voltage Drive Low Delay Fall Time Drive High Delay Rise Time Overcurrent Protection Current Limit Threshold VO = 0V 550 mA Sinking: PDR = 0.5V Sourcing: PDR = 3.5V Full ON, IPDR = 100µA Measured from BF_CUT threshold to 90% of PDR Measured from 90% to 10% Measured from BF_CUT/SLP threshold to 10% of PDR Measured from 10% to 90% 30 3.5 5 150 1.0 300 1.0 mA V ns µs ns µs Sinking: NDR = 0.5V Sourcing: NDR = 10V Full ON, INDR = 100µA Measured from BF_CUT threshold to 90% of NDR Measured from 90% to 10% Measured from BF_CUT/SLP threshold to 10% of NDR Measured from 10% to 90% 30 10 12 150 1.0 300 1.0 mA V ns µs ns µs BF_CUT = SLP = 5V 1.0 2.0 0.8 10.0 V 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 www.DataSheet4U.com 500mA SmartLDO With Power Up Signal Sequencing PRELIMINARY - January 17, 2000 TM SC1545 BLOCK DIAGRAM PIN.


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