GS-R24F 2 A DC-DC converter modules Features ■ MTBF 1 000 000 hours (TA = 25°C) ■ 2 A max output current ■ 35 V max input voltage ■ 1.5 V max drop-out voltage ■ Remote logic inhibit/enable ■ Synchronization ■ Not-latching overload and short circuit protection ■ Thermal shutdown ■ Fixed or adjustable output ■ No heatsink required ■ Operating temperature range -25 °C ÷ 85 °C Description The GS-R24F series is a family of high efficiency step down switching voltage regulator, designed to replace linear regulators. Based on ST L5973 device, these non isolated regulators are suitable for various applications, including telecom, industry, computer and distributed power supply system having a wide range input voltage. Table 1. Device summary Output voltage Input voltage Output ripple Efficiency [V] [V] [mVpp] [%] GS-R24F0182.0 1.8 ± 4% 16 ÷ 35 25 72 Fixed output voltage GS-R24F0252.0 2.5 ± 4% 16 ÷ 35 25 76 Fixed output voltage GS-R24F0332.0 3.3 ± 4% 16 ÷ 35 25 82 Fixed output voltage GS-R24F0502.0 5.0 ± 4% 16 ÷ 35 25 85 Fixed output voltage GS-R24F0002.0 1.235 ÷ 5.5 16 ÷ 35 25 68 ÷ 85 Progr. output voltage GS-R24F1201.5 12 ± 4% 16 ÷ 35 100 91 Fixed output voltage GS-R24F0001.0 3.3 ÷ 24 16 ÷ 35 100 ÷ 250 78 ÷ 96 Progr. output voltage Order codes February 2008 Rev 2 Notes 1/13 www.st.com 13 Contents GS-R24F Contents 1 2 Pin settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1 Pin connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.2 Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.1 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.2 Thermal data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.3 Thermal de-rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4 Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 5 4.1 Input voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 4.2 Reference voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 4.3 Inhibit function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 4.4 Multiple units synchronization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 4.5 Current limitation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 4.6 Thermal shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 4.7 Output voltage programming (GS-R24F0002.0 and GS-R24F0001.0) 7 4.8 Loop compensation (GS-R24F0002.0 and GS-R24F0001.0) . . . . . . . . . . 7 4.9 Soldering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Additional features and protections . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 5.1 Output overvoltage protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 6 Ordering scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 7 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 2/13 GS-R24F Pin settings 1 Pin settings 1.1 Pin connection Figure 1. 1.2 Pin connection and mechanical data (dimensions in mm) Pin description Table 2. Pin description Name Function Description 1 INH A logic high level disables the device. When the pin is open, an internal pull up disables the device 2 Vref 3.3 V reference voltage 3 Input + DC input voltage 4 Input + DC input voltage 5 Input GND Return for input voltage source 6 Input GND Return for input voltage source 7 Output GND Return for output voltage source 8 Output GND Return for output voltage source 9 Vout Regulated power output 10 Vout Regulated power output 11 FB Feedback input, available on adjustable device and on request for additional compensation 12 Sync Master/Slave synchronization 3/13 Maximum ratings GS-R24F 2 Maximum ratings 2.1 Absolute maximum ratings Table 3. Absolute maximum ratings Symbol VI IOUT 2.2 Parameter DC input voltage Maximum output current 36 V internally limit INH -0.3 to VI V V12 Sync -0.3 to 4 V V11 FB 4 V Value Unit Thermal data Absolute maximum ratings Symbol Parameter Tstg Storage temperature range -40 ÷ 105 °C Top Operating ambient temperature -25 ÷ 85 °C Test condition Value Unit VI = 16 ÷ 35 V --------TA = 60 °C 1.95 VI = 16 ÷ 35 V---------TA = 65 °C 1.85 VI = 16 ÷ 35 V ---------TA = 70 °C 1.75 VI = 16 ÷ 35 V ---------TA = 75 °C 1.65 VI = 16 ÷ 35 V ---------TA = 80 °C 1.55 VI = 16 ÷ 35 V ------ --TA = 85 °C 1.40 Thermal de-rating Table 5. Symbol Io 4/13 Unit V1 Table 4. 2.3 Value Thermal de-rating for free air condition (all versions) Parameter Output current A GS-R24F 3 Electrical characteristics Electrical characteristics TA = 25 °C, unless otherwise specified Table 6. Symbol Electrical characteristics (all version) Parameter Test condition Min Typ Max Unit 25 35 mVpp 100 mVpp 250 mVpp Vr Ripple voltage VI =24 V Io = 2A for GS-R24Fyyy2.0 Vr Ripple voltage VI =24 V Io = 1.5 A for GS-R24F1201.5 Vr Ripple voltage VI =24V Io = 1 A for GS-R24F0001.0 Temperature stability VI =Vo + 1.5 V Io = 2 A Io Output current VI =16 ÷ 35 V for GS-R24Fyyy2.0 0 2 A Io Output current VI =16 ÷ 35 V for GS-R24F1201.5 0 1.5 A Io Output current VI =16 ÷ 35 V for GS-R24F0001.0 0 1 A IoL Current limit VI =16 ÷ 35 V 2.5 Iq Quiescent current VI =24 V Io = 0 A 1.8 2.5 mA 80 150 µA 225 250 275 kHz 3.234 3.3 3.366 V 8 10 30 mA 0.8 V Iqst-by fs Vref 100 mV/°C Total stand-by quiescent Vinh>2.2 V Vi = 35 V current Switching frequency VI = 24 V Io = 2 A Reference voltage VI = 16 ÷ 35 V Iref = 0 ÷ 5 mA Short circuit current Device ON INH VFB A INH threshold voltage Feedback voltage Device OFF 2.2 Vi=16 ÷ 35 V IO=0 ÷ 2 A 1.22 V 1.235 1.25 V 5/13 Application information 4 Application information 4.1 Input voltage GS-R24F The recommended maximum operating Dc input voltage is 35 V including ripple voltage. 4.2 Reference voltage No capacitor is required for stability. 4.3 Inhibit function The inhibit feature allows to put the device in stand-by mode. With INH pin 1 is higher than 2.2 V the device is disabled and the current consumption is reduced to less than 150 µA for VI = 35 V. With INH pin lower than 0.8 V, the device is enabled. If the INH pin is left floating, an internal pull up ensures that the voltage at the pin reaches the inhibit threshold and the device is disabled. The pin can be pulled to VI to disable the device. 4.4 Multiple units synchronization Using more than one unit on the same circuit, it is possible to synchronize the switching frequency, connecting all pin 12 together (see Figure 5). The unit with higher frequency becomes the master. 4.5 Current limitation The device has two current limit protections, pulse by pulse and frequency fold back. The current is sensed through a resistor and if it reaches the threshold, the on time is reduced and consequently the output voltage, too. Since the minimum switch ON time (necessary to avoid false overcurrent signal) is not enough to obtain a sufficiently low duty cycle at 250 Hz, the output current could increase again, in strong overcurrent or short circuit conditions. For this reason the switching frequency is also reduced to keep the inductor current within its maximum threshold limit. The frequency depends on the feedback voltage. As the feedback voltage decreases (due to the reduced duty cycle), the switching frequency decrease too. 6/13 GS-R24F 4.6 Application information Thermal shutdown The shutdown block generates a signal that turns off the power stage if the temperature of the internal chip goes higher than a fixed internal threshold (150°C min). The sensing element of the chip is very close to the PDMOS area, so ensuring an accurate and fast temperature detection. An hysteresis of approximately 20 °C avoids that the devices turns on and off continuously. 4.7 Output voltage programming (GS-R24F0002.0 and GSR24F0001.0) The GS-R24F0002.0 output voltage is 5.54 V ±4 %, the GS-R24F0001.0 output voltage is 24.44 V ±4 %, to reduce these values connect a resistor between pin 11 (FB) and pin 10 (Vout). The resistor must be located very close to the proper pins, to minimize the injected noise (see figure 2). The resistor value is calculated using the following formula: for GS-R24F0002.0 Rv = [(Vout - 1.235) * 11.3] / (5.54 - Vout) --[kΩ]; for GS-R24F0001.0 Rv = [(Vout - 1.235) * 62] / (24.44 - Vout) --[kΩ]. Vout can be adjusted between 1.235 V (Rv = 0 Ω) and 5.54 V/24.44 V (Rv = open). 4.8 Loop compensation (GS-R24F0002.0 and GS-R24F0001.0) If required by particular load conditions, it is possible to change the feedback loop compensation, adding an external capacitor between pin 11 (FB) and pin 10 (Vout), which will act as speed up (see Figure 4). 7/13 Application information 4.9 GS-R24F Soldering Soldering phase has to be execute with care : in order to avoid undesired melting phenomenon, particular attention has to be take on the set up of the peak temperature. Here following some suggestions for the temperature profile based on IPC/JEDEC J-STD-020C ,July 2004 recommendations. Table 7. Soldering Profile feature Average ramp up rate ( TSMAX to TP) 3 °C / sec max Preheat Temperature min ( TS MIN) Temperature max ( TS MAX) Time (TS MIN to TS MAX) ( tS ) 150 °C 200 °C 60 – 100 sec Time maintained above : Temperature TL Time tL 217 °C 40 – 70 sec Peak temperature (TP) 240 + 0 °C Time within 5 °C of actual peak temperature (tP) 10 – 20 sec Ramp down rate Time from 25 °C to peak temperature Figure 2. 8/13 PB free assembly Soldering 6 °C / sec 8 minutes max GS-R24F Additional features and protections 5 Additional features and protections 5.1 Output overvoltage protection The overvoltage protection, OVP, is realized by using an internal comparator, whose input is connected to the feedback. It turns off the power stage when the OVP threshold is reached. This threshold is typically 30 % higher than the feedback voltage. Figure 3. Output voltage programming Figure 5. Multiple units synchronization Figure 4. Loop compensation 9/13 Additional features and protections Figure 6. 10/13 PCB footprint (dimensions in mm) GS-R24F GS-R24F 6 Ordering scheme Ordering scheme Table 8. Ordering information scheme GS- R24 F018 2.0 Input voltage 24 = 24 V Output voltage 018 = 1.8 V 025 = 2.5 V 033 = 3.3 V 050 = 5.0 V 120 = 12 V 000 = 1.235 ÷ 5.5 V / 3.3 ÷ 24 V Output current 2.0 = 2 A 1.5 = 1.5 A 1.0 = 1 A 11/13 Revision history 7 GS-R24F Revision history Table 9. 12/13 Document revision history Date Revision Changes 13-Oct-2006 1 Initial release 27-Feb-2008 2 Added: Section 4.9: Soldering on page 8 GS-R24F Please Read Carefully: Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice. All ST products are sold pursuant to ST’s terms and conditions of sale. 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