GS-R400 Family 20W TO 140W STEP-DOWN SWITCHING REGULATOR FAMILY FEATURES MTBF in excess of 200,000 hours 4A max output current 46V max input voltage 4V max drop-out voltage Soft start Remote logic inhibit/enable Remote output voltage sense Non-latching overload and short circuit protection Crow-bar output overvoltage protection DESCRIPTION The GS-R400 series is a versatile family of high current, high voltage step-down switching voltage regulators. The integral heatsink allows a large power handling capability and it provides also an effective shielding to minimize EMI. SELECTION CHART Type Ordering Number Output Voltage (V) Input Voltage (V) Output Ripple (mVpp) GS-R405 5.1 ± 2% 9 to 46 GS-R412 12.0 ± 4% GS-R415 15.0 ± 4% GS-R424 Regulation Efficiency Notes Line (mV/V) Load (mV/A) (%) 25 2 20 70 16 to 46 50 5 40 80 " 19 to 46 65 5 60 85 " 24.0 ± 4% 28 to 46 100 6 90 90 " GS-R405S 5.1 ± 2% 9 to 46 25 2 20 70 GS-R400V 5.1 to 40 Vo+4 to 46 25 to 100 6 20 to 90 70 to 90 Progr. output voltage GS-R400VB 5.1 to 40 Vo+4 to 46 25 to 100 6 20 to 90 70 to 90 Progr. output voltage and current. Frequency synchr. Fixed output voltage Reset output Note: The line regulation is measured at Iout=1A The load regulation is measured at Vin=Vo+8V and Iout=1 to 3A For VO ≥ 36V and Io = 4A an external heatsink or forced ventilation are required. ABSOLUTE MAXIMUM RATINGS Symbol Parameter Value Unit Vi DC Input Voltage 48 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 * GS-R405S only June 1994 1/5 GS-R400 FAMILY CONNECTION DIAGRAM AND MECHANICAL DATA Pin 2 GS-R405S only Pin 5,6,7 GS-R400VB only Pin 12 GS-R400V/VB only Dimensions in mm Bottom view PIN DESCRIPTION Pin Function Description 1 Inhibit The module is disabled by a high logic level applied to this pin. 2 Reset Reset output (GS-R405S only). 3 + Input DC input voltage. Recommended maximum voltage is 46V. 4 Input GND Return for input voltage source. 5 Oscillator 100kHz oscillator output. To be connected to Sync (pin 6) input if the unit is a master and left open if it is a slave (GS-R400VB only). See fig. 5. 6 Sync Synchronization input. To be connected to the Oscillator output (pin 5) of the master (GSR400VB only). See fig. 5. 7 Current limiting A resistor (≥ 2.2kΩ) connected from this pin to pin 9 sets the current limiting level (GS-R400VB only). 8 Output GND Return for output current path. Internally connected to pin 4. 9 – Sense Senses the remote load return. Must be tied to pin 8 when the remote sensing feature is not used. See fig. 1. 10 + Sense Senses the remote load high side. Must be tied to pin 11 when the remote load sensing feature is not used. See fig. 1. 11 + Output Regulated DC output voltage. 12 Program A resistor (≤ 18kΩ) connected between this pin and pin 10 sets the output voltage (GS-R400V and GS-R400VB only). 2/5 GS-R400 FAMILY ELECTRICAL CHARACTERISTICS (TA = 25°C unless otherwise specified) Symbol Parameter Test Conditions ∆Vo/∆T Temperature Stability Vi = Vo+8V Io = 1A Io Output Current Vi = Vo+8V IoL Current Limit Vi = Vo+8V Iisc Average Input Current fs Min Typ Max 0.2/1.6 mv/°C 4 A 5 8 A Vi = 46V Output Shorted 0.1 0.2 A Switching Frequency Io = 1A 100 KHz Supply Voltage Rejection fo = 100Hz Io =1A 4/12 mV/V Vr Ripple Voltage Io = 2A 25/150 mVpp tss Soft Start Time Vi = Vo+8V 10/35 ms SVR Vinhl Low Inhibit Voltage Vinhh High Inhibit Voltage Iinhh High Inhibit Input Current 0.2 Unit 2 Vinh = 5V 0.8 V 5.5 V 500 µA Crow-bar Delay Time 5 µs Vrh* Reset High Level 5 V Vrl* Reset Low Level trd* Reset Delay Time Vcth Crowbar Intervention Threshold ∆Vo Total Remote Sense Compensation Rth Thermal Resistance tcb Irl = 5mA Irl = 10mA 0.2 0.4 100 ms Vo•1.25 V 500 Case to ambient V 5 mV °C/W * GS-R405S only USER NOTES Thermal Characteristics Input Voltage The case-to-ambient thermal resistance of all the GS-R400 modules is about 5°C/W. This produces a 50°C temperature increase of the module surface for 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. The recommended operating maximum DC input voltage is 46V inclusive of the ripple voltage. Remote Sensing The remote voltage sense compensation range is for a total drop of 500mV equally shared between the load connecting wires. It is a good practice to shield the sensing wires to avoid oscillation. Each sense input must be connected to its companion output power pin when the remote sense capability is not used (see fig. 1). Case Grounding The module case is isolated from the electrical circuit of the switching regulator. It can be grounded using the 4 corner pins. The PCB area below the module can be used as an effective sixth side shield against EMI. Input Impedance 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 the module as possible is recommended. Suitable capacitors should have a RMS current capability of 2.5ARMS with a working voltage of 50 VDC and an ESR of 0,1Ω at 100 kHz. When space 3/5 GS-R400 FAMILY is a limitation, a 22µF ceramic multilayer capacitor must be connected to the module input pins. Output Voltage Programming The GS-R400V and GS-R400VB output voltage is programmed by using a resistor (see pin function table and fig. 4). The resistor must be located very close the module and the PCB layout must mimimize injected noise. The value of the resistor is calculated by using the following formula: Vo –1 kΩ Rv = 2.67 5.1 Vo can be adjusted between 5.1 and 40V. Current Limiting Programming The value of the resistor is calculated by using the following formula: Ri = [2.2 + (5•Io)] kΩ Module Protection The modules are protected against occasional and permanent short circuits of the output pin to ground, as well as against output current overload. When the output current 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 crowbar output overvoltage protection is activated whenever the output voltage exceeds the nominal output voltage by more than 25%. The GS-R400VB current limiting is programmed by using a resistor (see pin function table and fig. 4). Figure 1. Load Connection Figure 2. Remote Inhibit Operation 4/5 Figure 3. Reset Operation GS-R400 FAMILY Figure 4. Voltage and Current Programming Figure 5. Multiple Units Synchronization 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