SC1543 400mA/200mA Dual 3.3V Smart Power Switch PRELIMINARY - October 9, 2000 TEL:805-498-2111 FAX:805-498-3804 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. 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) 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. ORDERING INFORMATION 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. Part Number (1) Package SC1543IMSTR MSOP-8 Note: (1) Only available in tape and reel packaging. A reel contains 2500 devices. The SC1543 is available in an MSOP-8 surface mount package. APPLICATION CIRCUIT SHUTDOWN U1 1 3.3V IN 2 3 4 3.3VAUX IN VIN1 SHDN VIN1 VOUT VIN2 VOUT VIN2 GND 8 7 3.3V OUT 6 5 SC1543 CIN1 1uF CIN2 1uF COUT 10uF 1 © 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 SC1543 400mA/200mA Dual 3.3V Smart Power Switch PRELIMINARY - October 9, 2000 ABSOLUTE MAXIMUM RATINGS Parameter Symbol Maximum Units Input Supply Voltage VIN1,2 -0.5 to +6 V Output Current From: VIN1 VIN2 IO 400 200 mA Operating Ambient Temperature Range TA -40 to +85 °C Operating Junction Temperature Range TJ -40 to +125 °C Storage Temperature Range TSTG -65 to +150 °C Lead Temperature (Soldering, 10 Sec.) TLEAD 300 °C θJA 206 °C/W Thermal Impedance Junction to Ambient ELECTRICAL CHARACTERISTICS (1) Unless specified, TA = 25°C, SHDN = 0V, CO = 10µF, IO = 400mA (when power is being supplied from VIN1, 200mA when power is being supplied from VIN2). Values in bold apply over full operating temperature range. Parameter Symbol Conditions Min Typ Max Units 3.0 3.3 3.6 V VIN1 > VIN2, IO = 0mA 150 300 µA VIN1 < VIN2 15 50 VIN1 = SHDN = 3.3V 1 10 VIN1 Supply Voltage VIN1 Quiescent Current IQ1 Reverse Leakage From VIN2(2) IVIN1 VIN1 = 0V, VIN2 = 3.6V, IO = 0mA 0.25 1.00 µA 3.3 3.6 V VIN2 > VIN1, IO = 0mA 150 300 µA VIN2 < VIN1 1 10 VIN2 = SHDN = 3.3V 1 10 VIN2 Supply Voltage VIN2 Quiescent Current IQ2 (2) Reverse Leakage From VIN1 IVIN2 3.0 VIN1 = 3.6V, VIN2 = 0V, IO = 0mA 0.25 1.00 µA VTH 2.80 2.90 3.00 V VHYST 130 mV VIN1 Threshold Voltage Threshold Voltage Hysteresis Power Switches VIN1 Pass Device RDS(ON)(2) RDS(ON)1 VIN1 = 3.3V, VIN2 = 0V 100 250 mΩ (2) RDS(ON)2 VIN1 = 0V, VIN2 = 3.3V 150 400 mΩ VIN2 Pass Device RDS(ON) 2 © 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 SC1543 400mA/200mA Dual 3.3V Smart Power Switch PRELIMINARY - October 9, 2000 (1) ELECTRICAL CHARACTERISTICS (Cont.) Unless specified, TA = 25°C, SHDN = 0V, CO = 10µF, IO = 400mA (when power is being supplied from VIN1, 200mA when power is being supplied from VIN2). Values in bold apply over full operating temperature range. Parameter Symbol Conditions Min Typ Max Units SHDN Input High Voltage VIH Input Low Voltage VIL V 1.8 0.4 V Over Temperature Protection High Trip Level Hysteresis THI 165 °C THYS 20 °C NOTES: (1) This device is ESD sensitive. Use of standard ESD handling precautions is required. (2) Guaranteed by design. OUTPUT TRUTH TABLE (1) Input Conditions VOUT VIN1 > VTH Connected to VIN1 VIN1 < VTH Connected to greater of VIN1 and VIN2 NOTES: (1) See Electrical Characteristics for definition for VTH. 3 © 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 400mA/200mA Dual 3.3V Smart Power Switch SC1543 PRELIMINARY - October 9, 2000 BLOCK DIAGRAM PIN CONFIGURATION Top View (MSOP-8) PIN DESCRIPTION Pin Pin Name Pin Function 1,2 VIN1 Primary input supply, nominally 3.3V. 3,4 VIN2 Secondary input supply, nominally 3.3V. 5 GND Power and logic ground. 6,7 VOUT 3.3V out. 8 SHDN Shutdown, with internal pull-down. Device is OFF when this pin is High. Leave open if shutdown feature is not required. 4 © 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 400mA/200mA Dual 3.3V Smart Power Switch SC1543 PRELIMINARY - October 9, 2000 OUTLINE DRAWING - MSOP-8 LAND PATTERN - MSOP-8 ECN00-1361 5 © 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320