SC1543

400mA/200mA Dual 3.3V Smart Power Switch PRELIMINARY - October 9, 2000 SC1543 TEL:805-498-2111 FAX:805-498-3804 WEB:http://www.semtech.com DESCRIPTION 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. FEATURES •= •= •= •= •= 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 MSOP-8 SC1543IMSTR Note: (1) Only available in tape and reel packaging. A reel contains 2500 devices. APPLICATION CIRCUIT SHUTDOWN U1 3.3V IN 1 2 3 3.3VAUX IN 4 VIN1 VIN1 VIN2 VIN2 SC1543 CIN1 1uF CIN2 1uF COUT 10uF SHDN VOUT VOUT GND 8 7 6 5 3.3V OUT 1 © 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 400mA/200mA Dual 3.3V Smart Power Switch PRELIMINARY - October 9, 2000 SC1543 ABSOLUTE MAXIMUM RATINGS Parameter Input Supply Voltage Output Current From: VIN1 VIN2 Operating Ambient Temperature Range Operating Junction Temperature Range Storage Temperature Range Lead Temperature (Soldering, 10 Sec.) Thermal Impedance Junction to Ambient (1) Symbol VIN1,2 IO TA TJ TSTG TLEAD θJA Maximum -0.5 to +6 400 200 -40 to +85 -40 to +125 -65 to +150 300 206 Units V mA °C °C °C °C °C/W ELECTRICAL CHARACTERISTICS 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 VIN1 Supply Voltage Quiescent Current Symbol Conditions Min Typ Max Units VIN1 IQ1 VIN1 > VIN2, IO = 0mA VIN1 < VIN2 VIN1 = SHDN = 3.3V 3.0 3.3 150 15 1 3.6 300 50 10 V µA Reverse Leakage From VIN2(2) VIN2 Supply Voltage Quiescent Current IVIN1 VIN2 IQ2 VIN1 = 0V, VIN2 = 3.6V, IO = 0mA 0.25 1.00 µA 3.0 VIN2 > VIN1, IO = 0mA VIN2 < VIN1 VIN2 = SHDN = 3.3V 3.3 150 1 1 3.6 300 10 10 V µA Reverse Leakage From VIN1 VIN1 Threshold Voltage Threshold Voltage Hysteresis Power Switches VIN1 Pass Device RDS(ON)(2) VIN2 Pass Device RDS(ON) (2) (2) IVIN2 VIN1 = 3.6V, VIN2 = 0V, IO = 0mA 0.25 1.00 µA VTH VHYST 2.80 2.90 3.00 130 V mV mΩ mΩ RDS(ON)1 RDS(ON)2 VIN1 = 3.3V, VIN2 = 0V VIN1 = 0V, VIN2 = 3.3V 100 150 250 400 2 © 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 400mA/200mA Dual 3.3V Smart Power Switch PRELIMINARY - October 9, 2000 SC1543 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. (1) Parameter SHDN Input High Voltage Input Low Voltage Over Temperature Protection High Trip Level Hysteresis Symbol Conditions Min Typ Max Units VIH VIL THI THYS 1.8 0.4 V V 165 20 °C °C NOTES: (1) This device is ESD sensitive. Use of standard ESD handling precautions is required. (2) Guaranteed by design. OUTPUT TRUTH TABLE Input Conditions VIN1 > VTH VIN1 < VTH (1) VOUT Connected to VIN1 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 PRELIMINARY - October 9, 2000 SC1543 BLOCK DIAGRAM PIN CONFIGURATION Top View (MSOP-8) PIN DESCRIPTION Pin 1,2 3,4 5 6,7 8 Pin Name VIN1 VIN2 GND VOUT SHDN Pin Function Primary input supply, nominally 3.3V. Secondary input supply, nominally 3.3V. Power and logic ground. 3.3V out. 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 PRELIMINARY - October 9, 2000 SC1543 OUTLINE DRAWING - MSOP-8 LAND PATTERN - MSOP-8 ECN00-1361 5 © 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320