GS-R24P 1.8W TO 8W STEP-DOWN SWITCHING REGULATOR FAMILY PRELIMINARY FEATURE ■ MTBF 1 000 000 hours (Tamb=25)C) ■ 1.5A max output current 35V max input voltage 1.5V max drop-out voltage Remote logic inhibit/enable Not-latching overload and short circuit protection Thermal shutdown Fixed or adjustable output No heatsink required ■ ■ ■ ■ ■ ■ ■ Packing type: V = vertical PTH DESCRIPTION The GS-R24P series is a family of high efficiency step down switching voltage regulator, designed to replace linear regulators. Based on STM L5973 device, this non isolated family of regulators are suitable for the full spectrum of applications including telecom, industry, computer and distributed power system applications having a widely ranging input voltage. Packing type: H = horizontal PTH -------------------S = horizontal SMD June 2004 This is preliminary information on a new product now in development. Details are subject to change without notice. 1/7 GS-R24P SELECTION CHART Type Ordering Number Output Voltage [V] Input Voltage [V] Output Ripple [mVpp] Efficiency [%] Package (P)* GS-R24(P)0181.5 1.8 ± 4% 16 ÷ 35 35 72 H-S-V Fixed output voltage GS-R24(P)0251.5 2.5 ± 4% 16 ÷ 35 35 76 H-S-V Fixed output voltage GS-R24(P)0331.5 3.3 ± 4% 16 ÷ 35 35 82 H-S-V Fixed output voltage GS-R24(P)0501.5 5.0 ± 4% 16 ÷ 35 35 85 H-S-V Fixed output voltage GS-R24(P)0001.5 1.235 ÷ 5.5 16 ÷ 35 50 68 ÷ 85 H-S Progr. output voltage Notes * Packing Legend (P) H = horizontal through hole S = horizontal SMD V = vertical through hole ABSOLUTE MAXIMUM RATINGS Symbol 2/7 Parameter Value Unit 36 V Vi DC Input Voltage (for GS-R24(P)XXX1.5) Iout Maximum Output Current int. limit V4 INH -0.3 to Vi V V6 FB 4 V Tstg Storage Temperature Range -40 ÷ 105 °C Top Operating Ambient Temperature -25 ÷ 70 °C Top1 Operating Ambient Temperature with current derating -25 ÷ 85 °C GS-R24P CONNECTION DIAGRAM AND MECHANICAL DATA GS-R24Vxxx1.5 GS-R24Hxxx1.5 GS-R24Sxxx1.5 3/7 GS-R24P PIN DESCRIPTION Pin Function Description 1 Input + 2 Input/Output GND 3 Vout Regulated power output 4 INH A logical level (active high) disables the device, when it is open an internal pull up disables the device 5 Vout-c 6 FB DC input voltage Return for input/output voltage source Regulated output point for additional compensation Feedback input, available on adjustable device and on request for additional compensation ELECTRICAL CHARACTERISTICS All versions (Tamb=25)C, unless otherwise specified.) Symbol Vr Parameter Test Condition Ripple Voltage Vi =24V Io = 1.5A Temperature Stability Vi =Vo + 1.5V Io = 1.5A Io Output Current Vi =16 ÷ 35V IoL Current Limit Vi =16 ÷ 35V Iq Quiescent Current Vi =24V Io = 0A fs Switching Frequency Vi =24V Io = 1.5A SRV Rth Min. Typ. Max. Unit 35 50 mVpp mV/°C 0 225 1.5 A 2.5 3.5 A 1.8 2.5 mA 250 275 kHz Supply Voltage Rejection Thermal Resistance mV/V Case to ambient °C/W ELECTRICAL CHARACTERISTICS for horizontal versions only (Tamb=25)C, unless otherwise specified.) Symbol Iqst-by INH Parameter Test Condition Total Stand-by Quiescent Current Vinh>2.2V Vi = 35V INH Threshold Voltage Device ON Device OFF VFB 4/7 Feedback Voltage Vi =16 ÷ 35V Io = 0÷1.5A Min. Typ. Max. Unit 80 150 µA 0.8 V 2.2 1.22 V 1.235 1.25 V GS-R24P USER NOTES Input Voltage The recommended operating maximum DC Input Voltage is 35V inclusive of ripple voltage. Inhibit function The inhibit feature allows to put in stand-by mode the device. With INH pin 4 higher than 2.2V the device is disabled and the power 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 is also Vi compatible. Current protection The device has two current limit protections, pulse by pulse and frequency fold back. The current is sensed through a resistor and if 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, in strong overcurrent or short circuit conditions, could increase again. For this reason the switching frequency is also reduced, so keeping the inductor current under its maximum threshold. The frequency depends on the feedback voltage. As the feedback voltage decreases (due to the reduced duty cycle), the switching frequency decrease too. 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 ºC). 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 20ºC avoids that the devices turns on and off continuously. Thermal Characteristics Output voltage programming (GS-R24H(S)0001.5 only) The GS-R24P output voltage is 5.54V ±4%, to reduce this value connect a resistor between pin 6 (FB) and pin 5 (Vout-c). The resistor must be located very close to the proper pins, to minimize the injected noise (see figure 1). The resistor value is calculated using the following formula: Rv=[(Vout-1.235)*11.3]/(5.54-Vout) --[kOhm] Vout can be adjusted between 1.235V (Rv=0 Ohm) and 5.54V (Rv=open) 5/7 GS-R24P Loop compensation (GS-R24H(S)0001.5 only) If required by particular load conditions, it is possible to change the feedback loop compensation, adding an external capacitor between pin 6 (FB) and pin 5 (Vout-c), which will act as speed up (see figure 2). ADDITIONAL FEATURES AND PROTECTIONS Feedback disconnection In case of feedback disconnection, the duty cycle increases versus the maximum allowed value, bringing the output voltage close to the input supply. THis condition could destroy the load. To avoid this dangerous condition, the device is turned off if the internal feedback pin remains floating. Output overvoltage protection The overvoltage protection, OVP, is realized by using an internal comparator, which input is connected to the feedback, that turns off the power stage when the OVP threshold is reached. This threshold is typically 30% higher than the feedback voltage. Figure 1 6/7 Figure 2 GS-R24P Information furnished is believed to be accurate and reliable. However, STMicroelectronics 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 STMicroelectronics. Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics. The ST logo is a registered trademark of STMicroelectronics. All other names are the property of their respective owners © 2004 STMicroelectronics - All Rights Reserved STMicroelectronics GROUP OF COMPANIES Australia - Belgium - Brazil - Canada - China -Czech Republic - Finland - France - Germany - Hong Kong - India - Israel - Italy - Japan - Malaysia - Malta - Morocco - Singapore - Spain - Sweden - Switzerland - United Kingdom - U.S.A. http://www.st.com 7/7