GS-R24F 2A DC/DC converter modules Features ■ MTBF 1 000 000 hours (TA = 25° C) ■ 2A max output current ■ 35V max input voltage ■ 1.5V 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. Order codes 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 Part number October 2006 Rev 1 Notes 1/12 www.st.com 12 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 Additional features and protections . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 5.1 Output overvoltage protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 6 Ordering scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 7 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2/12 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 1. 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 3.3V 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 3/12 Maximum ratings GS-R24F 2 Maximum ratings 2.1 Absolute maximum ratings Table 2. 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 ÷ 35V --------TA = 60°C 1.95 VI = 16 ÷ 35V---------TA = 65°C 1.85 VI = 16 ÷ 35V ---------TA = 70°C 1.75 VI = 16 ÷ 35V ---------TA = 75°C 1.65 VI = 16 ÷ 35V ---------TA = 80°C 1.55 VI = 16 ÷ 35V ------ --TA = 85°C 1.40 Thermal de-rating Table 4. Symbol Io 4/12 Unit V1 Table 3. 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 5. Symbol Electrical characteristics (all version) Parameter Test condition Min Typ Max Unit 25 35 mVpp 100 mVpp 250 mVpp Vr Ripple voltage VI =24V Io = 2A for GS-R24Fyyy2.0 Vr Ripple voltage VI =24V Io = 1.5A for GS-R24F1201.5 Vr Ripple voltage VI =24V Io = 1A for GS-R24F0001.0 Temperature stability VI =Vo + 1.5V Io = 2A Io Output current VI =16 ÷ 35V for GS-R24Fyyy2.0 0 2 A Io Output current VI =16 ÷ 35V for GS-R24F1201.5 0 1.5 A Io Output current VI =16 ÷ 35V for GS-R24F0001.0 0 1 A IoL Current limit VI =16 ÷ 35V 2.5 Iq Quiescent current VI =24V Io = 0A 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>2.2V Vi = 35V current Switching frequency VI = 24V Io = 2A Reference voltage VI = 16 ÷ 35V Iref = 0 ÷ 5mA Short circuit current Device ON INH INH threshold voltage VFB Feedback voltage SRV Supply voltage rejection Rth A Thermal resistance Device OFF 2.2 Vi=16 ÷ 35V IO=0 ÷ 2A 1.22 V 1.235 1.25 V mV/V Case to ambient °C/W 5/12 Application information 4 Application information 4.1 Input voltage GS-R24F The recommended maximum operating DC Input Voltage is 35V 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 2.2V the device is disabled and the current consumption is reduced to less than 150µA for VI = 35V. With INH pin lower than 0.8V, 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 4). 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 250Hz, 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. 6/12 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 GS-R24F0001.0) The GS-R24F0002.0 output voltage is 5.54V ±4%, the GS-R24F0001.0 output voltage is 24.44V ±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 1.235V (Rv = 0Ω) and 5.54V/24.44V (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 3). 7/12 Additional features and protections GS-R24F 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. 8/12 Figure 2. Output voltage programming Figure 4. Multiple units synchronization Figure 3. Loop compensation GS-R24F Additional features and protections Figure 5. P.C.B. Footprint (dimensions in mm) 9/12 Ordering scheme 6 GS-R24F Ordering scheme Table 6. Ordering information scheme GS- Input Voltage 24 = 24V Output Voltage 018 = 1.8V 025 = 2.5V 033 = 3.3V 050 = 5.0V 120 = 12V 000 = 1.235 ÷ 5.5V / 3.3 ÷ 24V Output Current 2.0 = 2A 1.5 = 1.5A 1.0 = 1A 10/12 R24 F018 2.0 GS-R24F 7 Revision history Revision history Table 7. Revision history Date Revision 13-Oct-2006 1 Changes Initial release 11/12 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. Purchasers are solely responsible for the choice, selection and use of the ST products and services described herein, and ST assumes no liability whatsoever relating to the choice, selection or use of the ST products and services described herein. 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