VERY LOW DROPOUT 1.5 AMP REGULATOR WITH ENABLE October 3, 2000 SC1565 TEL:805-498-2111 FAX:805-498-3804 WEB:http://www.semtech.com DESCRIPTION The SC1565 is a high performance positive voltage regulator designed for use in applications requiring very low dropout voltage at up to 1.5 Amps. Since it has superior dropout characteristics compared to regular LDOs, it can be used to supply 2.5V on motherboards or 2.8V on peripheral cards from the 3.3V supply thus allowing the elimination of costly heatsinks. Additionally, the 5-lead TO-220 and SO-8 versions have an enable pin to further reduce power dissipation while shut down. The SC1565 provides excellent regulation over variations in line, load and temperature. The SC1565 is available in the popular SO-8 surface mount package with two internally preset output voltage options, which are also adjustable using external resistors. Also available are 5-lead and 3-lead TO-220 2.5V options (fixed output only for the 3-lead option) and fixed output SOT-223 options. FEATURES •= 350mV dropout @ 1.5A •= Adjustable output from 1.2V to 4.8V(1) •= 2.5V and 1.8V options (adjustable externally using resistors)(1) •= Over current and over temperature protection •= Enable pin(1) •= 10µA quiescent current in shutdown(1) •= Low reverse leakage (output to input) •= Surface mount and through-hole packages •= Full industrial temperature range Note: (1) SO-8 and TO-220-5L packages only. APPLICATIONS •= Battery powered systems •= Motherboards •= Peripheral cards •= PCMCIA cards ORDERING INFORMATION (1) DEVICE SC1565IS-X.X.TR(2) SC1565IST-X.X.TR SC1565IT-X.X SO-8 (2) SOT-223 (3) SC1565I5T-X.X Notes: (1) Where -X.X denotes voltage options. Available voltages are: 2.5V and 1.8V. Output voltage can be adjusted (except SOT-223 and TO-220-3) using external resistors, see Pin Description. (2) Only available in tape and reel packaging. A reel contains 2500 devices. (3) Only available in tube packaging (no suffix required). PACKAGE TO-220-3 (3) TO-220-5 TYPICAL APPLICATIONS U1 1 ENABLE 2 VIN 3 VO 4 R1 C1 EN GND VIN GND VO GND ADJ GND U1 SC1565I5T-2.5 8 2 VIN 7 6 1 ENABLE VIN VO EN GND ADJ 4 VO 5 R1 5 3 SC1565IS-X.X C1 C2 R2 C2 VO = 1.200 (R1 + R2) R2 Volts R2 VO = 1.200 (R1 + R2) R2 Volts VIN U1 1 ENABLE 2 VIN 3 VO 4 C1 C2 EN 1 GND VIN GND VO GND ADJ GND U1 SC1565IT-2.5V and SC1565IST-X.X 3 VIN VO VO 8 7 6 GND C1 C2 2 5 SC1565IS-X.X Notes: (1) Maximum VO setpoint for 1.8V parts = 5.4V. (2) This device is designed to operate with ceramic input and output capacitors. 1 © 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 VERY LOW DROPOUT 1.5 AMP REGULATOR WITH ENABLE SC1565 October 3, 2000 ABSOLUTE MAXIMUM RATINGS Parameter Symbol Max Units Input Voltage VIN 5.5 V Power Dissipation PD Internally Limited W θJA 65 63 50 °C/W θJC 39 27 3 °C/W Operating Ambient Temperature Range TA -40 to 85 °C Operating Junction Temperature Range TJ -40 to 150 °C Storage Temperature Range TSTG -65 to 150 °C Lead Temperature (Soldering) 10 Sec. TLEAD 300 °C ESD Rating (Human body model) ESD 4 kV Thermal Resistance Junction to Ambient SO-8(1) SOT-223 TO-220-X Thermal Resistance Junction to Case SO-8 SOT-223 TO-220-X Note: (1) 1 square inch of FR-4, double sided, 1 oz. minimum copper weight. ELECTRICAL CHARACTERISTICS Unless specified: VEN = VIN Adjustable Option (VADJ > VTH(ADJ)): VIN = 2.2 to 5.5V and IO = 10µA to 1.5A Fixed Options (VADJ = GND): VIN = (VO + 0.7V) to 5.5V and IO = 0A to 1.5A Values in bold apply over the full operating temperature range. Parameter Symbol Test Conditions Min Typ Max Units 5.5 V VIN Supply Voltage Range Quiescent Current VIN IQ 2.2 VIN = 3.3V 0.75 1.75 mA VIN = 5.5V, VEN = 0V 10 35 µA 0.99VO VO 1.01VO V 0.98VO VO 1.02VO VO Output Voltage(1) VO VIN = VO + 0.7V, IO = 10mA (Internal Fixed Voltage) (1) Line Regulation (1) Load Regulation REG(LINE) VIN = (VO + 0.25V) to 5.5V, IOUT = 10mA 0.035 0.3 % REG(LOAD) VIN = VO + 0.7V 0.2 0.4 % 2 © 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 VERY LOW DROPOUT 1.5 AMP REGULATOR WITH ENABLE SC1565 October 3, 2000 ELECTRICAL CHARACTERISTICS Unless specified: VEN = VIN Adjustable Option (VADJ > VTH(ADJ)): VIN = 2.2 to 5.5V and IO = 10µA to 1.5A Fixed Options (VADJ = GND): VIN = (VO + 0.7V) to 5.5V and IO = 0A to 1.5A Values in bold apply over the full operating temperature range. Parameter (2) Dropout Voltage Symbol Test Conditions VD ILOAD = 10mA Min Typ Max Units 2.5 10 mV 20 ILOAD = 500mA 115 300 mV 400 ILOAD = 1A 225 400 mV 500 ILOAD = 1.5A 350 500 mV 600 Minimum Load Current (3) Current Limit IO VIN = VO + 0.7V ICL 1 10 µA 1.50 2.50 3.50 A 1.188 1.200 1.212 V ADJ Reference Voltage(1) VREF VIN = 2.2V, VADJ = VOUT, IO = 10mA 1.176 Adjust Pin Current(4) IADJ (5) Adjust Pin Threshold VADJ = VREF VTH(ADJ) 0.10 1.224 10 50 nA 0.20 0.40 V 1.5 10 µA EN Enable Pin Current IEN VEN = 0V, VIN = 3.3V Enable Pin Threshold VIH VIN = 3.3V VIL VIN = 3.3V V 1.8 0.4 OVER TEMPERATURE PROTECTION High Trip level Hysteresis THI 170 °C THYST 20 °C NOTES: (1) Low duty cycle pulse testing with Kelvin connections required. (2) Defined as the input to output differential at which the output voltage drops to 1% below the value measured at a differential of 0.7V. (3) Required to maintain regulation. Voltage set resistors R1 and R2 are usually utilized to meet this requirement. Adjustable versions only. (4) Guaranteed by design. (5) When VADJ exceeds this threshold, the “Sense Select” switch disconnects the internal feedback chain from the error amplifier and connects VADJ instead. 3 © 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 VERY LOW DROPOUT 1.5 AMP REGULATOR WITH ENABLE SC1565 October 3, 2000 BLOCK DIAGRAM * * * Not on 3-lead TO-220 PIN DESCRIPTIONS Pin Name ADJ Pin Functiom This pin, when grounded, sets the output voltage to that set by the internal feedback resistors. If external feedback resistors are used, the output voltage will be (See Application Circuit): VO = 1.200 (R1 + R2) R2 Volts EN Enable Input. Pulling this pin below 0.4V turns the regulator off, reducing the quiescent current to a fraction of its operating value. The device will be enabled if this pin is left open. Connect to VIN if not being used. GND Reference ground. Use all four pins on the SO-8 device for heatsinking. Use the tab on the TO-220 devices for heatsinking. VIN Input voltage. For regulation at full load, the input to this pin must be between (VO + 0.7V) and 5.5V. Minimum VIN = 2.2V. VO This pin is the power output of the device. 4 © 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 VERY LOW DROPOUT 1.5 AMP REGULATOR WITH ENABLE SC1565 October 3, 2000 PIN CONFIGURATIONS SC1565 3-PIN VERSIONS PIN FUNCTION 1 VIN 2 GND 3 VO TAB IS GROUND PIN FUNCTION 1 VIN 2 GND 3 VO TAB IS GROUND TO-220-3 SOT-223 Top View SC1565 5-PIN VERSIONS PIN FUNCTION 1 EN 2 VIN 3 GND 4 VO 5 ADJ TAB IS GROUND SO-8 TO-220-5 5 © 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 VERY LOW DROPOUT 1.5 AMP REGULATOR WITH ENABLE SC1565 October 3, 2000 TYPICAL CHARACTERISTICS Dropout Voltage vs. Output Current vs. Junction Temperature Dropout Voltage vs. Junction Temperature vs. Output Current 600 600 150°C 500 500 300 300 IO = 0.5A 200 200 100 100 0 0.00 IO = 1.0A 400 25°C 0°C -40°C VD (mV) VD (mV) 400 IO = 1.5A 0 0.25 0.50 0.75 1.00 1.25 1.50 1.75 -50 -25 0 25 IO (A) Output Voltage (2.5V) vs. Junction Temperature vs. Output Current 100 125 150 2.550 VIN = 3.2V VIN = 5.5V 2.540 2.540 2.530 2.530 2.520 2.520 IO = 10mA 2.510 VO (V) VO (V) 75 Output Voltage (2.5V) vs. Junction Temperature vs. Output Current 2.550 2.500 2.490 IO = 10mA 2.510 2.500 2.490 IO = 1.5A 2.480 2.480 2.470 2.470 2.460 2.460 2.450 IO = 1.5A 2.450 -50 -25 0 25 50 75 100 125 150 -50 -25 0 25 50 75 100 125 TJ (°C) TJ (°C) Reference Voltage vs. Junction Temperature vs. Output Current Reference Voltage vs. Junction Temperature vs. Output Current 1.225 150 1.225 VIN = 2.2V VIN = 5.5V 1.220 1.220 1.215 1.215 1.210 1.210 IO = 10mA 1.205 VREF (V) VREF (V) 50 TJ (°C) 1.200 1.195 IO = 1.5A 1.200 1.195 1.190 1.190 1.185 1.185 1.180 1.180 1.175 IO = 10mA 1.205 IO = 1.5A 1.175 -50 -25 0 25 50 TJ (°C) 75 100 125 150 -50 -25 0 25 50 75 100 125 150 TJ (°C) 6 © 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 VERY LOW DROPOUT 1.5 AMP REGULATOR WITH ENABLE SC1565 October 3, 2000 TYPICAL CHARACTERISTICS (Cont.) Quiescent Current vs. Junction Temperature Off-State Quiescent Current vs. Junction Temperature 600 10 VIN = 5.5V 9 580 8 570 7 IQ(OFF) (µA) IQ (µA) VIN = 3.3V 590 560 550 540 6 5 4 530 3 520 2 510 1 500 0 -50 -25 0 25 50 75 100 125 150 -50 -25 0 25 TJ (°C) APPLICATIONS INFORMATION Introduction The SC1565 is intended for applications such as graphics cards where high current capability and very low dropout voltage are required. It provides a very simple, low cost solution that uses very little pcb real estate. Additional features include an enable pin to allow for a very low power consumption standby mode, and a fully adjustable output. Component Selection Input capacitor - a 4.7µF ceramic capacitor is recommended. This allows for the device being some distance from any bulk capacitance on the rail. Additionally, input droop due to load transients is reduced, improving load transient response. Additional capacitance may be added if required by the application. Output capacitor - a minimum bulk capacitance of 10µF, along with a 0.1µF ceramic decoupling capacitor is recommended. Increasing the bulk capacitance will improve the overall transient response. The use of multiple lower value ceramic capacitors in parallel to achieve the desired bulk capacitance will not cause stability issues. Although designed for use with ceramic output capacitors, the SC1565 is extremely tolerant of output capacitor ESR values and thus will also work comfortably with tantalum output capacitors. External voltage selection resistors - the use of 1% resistors, and designing for a current flow ≥ 10µA is recommended to ensure a well regulated output (thus R2 ≤ 120kΩ). 50 75 100 125 150 TJ (°C) Thermal Considerations The power dissipation in the SC1565 is approximately equal to the product of the output current and the input to output voltage differential: PD ≈ (VIN − VOUT ) • I O The absolute worst-case dissipation is given by: PD ( MAX ) = (VIN ( MAX ) − VOUT ( MIN ) )• I O ( MAX ) + VIN ( MAX ) • I Q ( MAX ) For a typical scenario, VIN = 3.3V ± 5%, VOUT = 2.8V and IO = 1.5A, therefore: VIN(MAX) = 3.465V, VOUT(MIN) = 2.744V and IQ(MAX) = 1.75mA, Thus PD(MAX) = 1.09W. Using this figure, and assuming TA(MAX) = 70°C, we can calculate the maximum thermal impedance allowable to maintain TJ ≤ 150°C: R TH( J − A )(MAX ) = (T J( MAX ) − TA ( MAX ) PD ( MAX ) ) = (150 − 70 ) = 73.4° C / W 109 . This should be achievable for the SO-8 package using pcb copper area to aid in conducting the heat away, such as one square inch of copper connected to the ground pins of the device. The SOT-223 and TO-220 packages would not require heatsinking. Internal ground/power planes and air flow will also assist in removing heat. For higher ambient temperatures it may be necessary to use additional copper area. 7 © 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 VERY LOW DROPOUT 1.5 AMP REGULATOR WITH ENABLE SC1565 October 3, 2000 OUTLINE DRAWING - SO-8 JEDEC REF: MS-012AA LAND PATTERN - SO-8 8 © 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 VERY LOW DROPOUT 1.5 AMP REGULATOR WITH ENABLE SC1565 October 3, 2000 DEVICE OUTLINE SOT-223 LAND PATTERN SOT-223 9 © 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 VERY LOW DROPOUT 1.5 AMP REGULATOR WITH ENABLE SC1565 October 3, 2000 DEVICE OUTLINE - TO-220-3L DEVICE OUTLINE - TO-220-5L ECN00-1357 10 © 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320