GS-R51212 20W TRIPLE OUTPUT STEP-DOWN SWITCHING REGULATOR FEATURES MTBF in excess of 200,000 hours 4V max drop-out voltage Soft start Reset output Non-latching short circuit protection Crow-bar output overvoltage protection DESCRIPTION The GS-R51212 is a versatile triple output, high current, high voltage step-down switching regulator module that provides a +5V and two isolated 12V outputs. It is ideal for microprocessor based boards because it powers the logic and the communication ports and it has a Reset output for the correct system start-up. The integral heatsink allows a large power handling capability and it provides also an effective shielding to minimize EMI. MAIN CHARACTERISTICS Vi Input Voltage 9 to 40V Vo1 Io1 Output Voltage Output Current 5.1V 3.5A Vo2 Io2 Output Voltage Output Current 12V 0.1A Vo3 Io3 Output Voltage Output Current 12V 0.1A ABSOLUTE MAXIMUM RATINGS Symbol Parameter Value Unit Vi DC Input Voltage 42 V Irt Reset Output Sink Current 20 mA Tstg Storage Temperature Range – 40 to +105 °C Tcop Operating Case Temperature Range – 20 to +85 °C June 1994 1/5 GS-R51212 ELECTRICAL CHARACTERISTICS (TA = 25°C unless otherwise specified) Symbol Parameter Test Conditions Min Typ Max Unit 5.1 5.2 V Vo1 Output Voltage Vi = 24V Io1 = 2.5A 4.95 Vo2 Output Voltage Vi=24V Io2 = 0.1A 11.5 12.5 V Vo3 Output Voltage Vi = 24V Io3 = 0.1A 11.5 12.5 V Temperature Stability All Outputs ∆Vo/∆T Vi Input Voltage Io1 Output Current Vi = 24V Io2 Output Current Io3 0.2 mV/°C 9 40 V 0.5 3.5 A Vi = 24V 0.1 A Output Current Vi = 24V 0.1 A Iisc Average Input Current Vi = 40V Vo1 = 0V 0.1 0.2 A Iisc Average Input Current Vi = 40V Vo1/2/3 = 0V 0.1 0.2 A Iir Reflected Input Current Vi = 24V Io1 = 2.5A Io2,3 = 0.1A 200 Vis 5V to 12V Isolation Voltage 200 fs Switching Frequency η Efficiency Vi = 24V ∆Vo mApp VDC 100 kHz Io1 = 2.5A Io2,3 = 0.1A 70 % Line Regulation Io1 = 2.5A Vi = 15 to 25V Io2,3 = 0.1A 2 mV/V ∆Vo Load Regulation Vi = 24V Vi = 24V 35 600 mV/A SVR Supply Voltage Rejection 50/60Hz 4 mV/V Vor Output Ripple Voltage Vi = 24V Io1 = 2.5A 30 mVpp Von Output Noise Voltage Vi = 24V Io1 = 2.5A 40 mVpp 100 µA 0.2 V 100 ms 2/5 Io1 = 0.5 to 2.5A Io2,Io3 = 0.05 to 0.1A Irh Reset Leakage Current Vrl Reset Low Level trd Reset Delay Time tr1 Line Transient Recovery Time Io1 = 2.5A Vi = 15 to 35V 500 µs tr2 Load Transient Recovery Time Vi = 24V Io = 0.5 to 2.5A 200 µs tss Soft Start Time 10 ms tcd Crowbar Delay Time 5 µs 6.37 V 5 °C/W Vcth Crowbar Intervention Threshold Rth Thermal Resistance Ireset = 5mA Case to ambient GS-R51212 CONNECTION DIAGRAM AND MECHANICAL DATA Bottom view Dimensions in mm PIN DESCRIPTION Pin Function Description 1 Output 1 Regulated 5.1V output. 2 Output GND Return for output1 current path. Internally connected to pin 8. 3 Output 2 Regulated 12V output. 4 Ground 2 Return of output 3 current path. 5 Output 3 Regulated 12V output. 6 Ground 3 Return of output 3 current path. 7 Reset Open collector Reset output. 8 Input GND Return of input voltage source. Internally connected to pin 2. 9 + Input DC input voltage. Recommended maximum voltage is 40V. 3/5 GS-R51212 USER NOTES Input Voltage Figure 1. Output Current Capability vs. Operating Conditions The recommended operating maximum DC input voltage is 40V inclusive of the ripple voltage. Case Grounding The module case is internally connected to pin 2 and pin 8. The PCB area below the module can be used as an effective sixth side shield against EMI. Thermal Characteristics The case-to-ambient thermal resistance of the GS-R51212 module is about 5°C/W. This produces a 50°C temperature increase of the module surface for a 10W of internal power dissipation. Depending on the ambient temperature and/or on the power dissipation, an additional heatsink or forced ventilation may be required. Input Impedance Figure 2. Reset Operation The module has an internal capacitor connected between the input pins in order to assure PWM stability. This capacitor cannot handle large values of high frequency ripple current, and it can be permanently damaged if the primary energy source impedance is not adequate. The use of an external low ESR, high ripple current capacitor located as close to the module as possible is recommended. Suitable capacitors should have a RMS current capability of 2,5 ARMS with a working voltage of 50 VDC and an ESR of 0,1Ω at 100 kHZ. When space is a limitation, a 22µF ceramic multilayer capacitor must be connected to the module input pins. Module Protection The module is protected against occasional and permanent short circuits of the output pins to ground, as well as against output current overload. When the output current at 5V output exceeds the maximum value, the output is automatically disabled. After a fixed time the module starts again in a soft mode. The cycle is repeated until the overload condition is removed. A crow-bar output overvoltage protection is activated when the output voltage on Vo1 exceeds 6.37V. Output Current The output current of the main output is 3.5A. The max output current of the two 12V outputs is a function of the input voltage and of the main output current as shown in fig. 1. If the main current is zero, no voltage will be available on the 12V outputs. 4/5 Figure 3. Typical application GS-R51212 Information furnished is believed to be accurate and reliable. However, SGS-THOMSON Microelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of SGS-THOMSON Microelectronics. Specification mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. SGS-THOMSON Microelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of SGS-THOMSON Microelectronics. © 1994 SGS-THOMSON Microelectronics – All Rights Reserved SGS-THOMSON Microelectronics GROUP OF COMPANIES Australia - Brazil - China - France - Germany - Hong Kong - Italy - Japan - Korea - Malaysia - Malta - Morocco - The Netherlands Singapore - Spain - Sweden - Switzerland - Taiwan - Thailand - United Kingdom - U.S.A. 5/5