1/8 GS-R12HXXX2 october 2003 this is preliminary information on a new product now in development. details are subject to change without notice. feature n mtbf 1 000 000 hours ( t amb =25 ) c) n 2a max output current n 35v max input voltage n 1.5v max drop-out voltage n 3.3v 2% reference voltage n remote logic inhibit/enable n synchronization n not-latching overload and short circuit protection n thermal shutdown n fixed or adjustable output n no heatsink required description the GS-R12HXXX2 series is a family of high efficiency step down switching voltage regulator, designed to re- place linear regulators. based on stm l5973 device, this non isolated family of regulators are suitable for the full spectrum of applica- tions including telecom, industry, computer and distributed power system applications having a widely ranging input voltage. selection chart typ e ordering number output voltage [v] input voltage [v] output ripple [mvpp] efficiency [%] notes gs-r12h0122 1.235 3 % 4.5 15 20 68 fixed output voltage gs-r12h0182 1.8 4 % 4.5 15 20 72 fixed output voltage gs-r12h0252 2.5 4 % 4.5 15 20 76 fixed output voltage gs-r12h0332 3.3 4 % 4.5 15 20 82 fixed output voltage gs-r12h0502 5.0 4 % 6.6 15 20 85 fixed output voltage gs-r12h0002 1.235 5.0 4.5 15 20 68 85 progr. output voltage gs-r24h0332 3.3 4 % 16 35 20 82 fixed output voltage ordering number: GS-R12HXXX2 preliminary 2.5w to 24w step-down switching regulator family
GS-R12HXXX2 2/8 absolute maximum ratings gs-r24h0502 5.0 4 % 16 35 20 85 fixed output voltage gs-r24h1201.5 12 4 % 16 35 100 91 fixed output voltage gs-r24h0001 3.3 24 16 35 100 250 78 96 progr. output voltage symbol parameter value unit vi dc input voltage (for GS-R12HXXX2) 16 v dc input voltage (for gs-r24hxxx) 36 v i out maximum output current int. limit v 9 inh -0.3 to v i v v 10 sync -0.3 to 4 v v 11 fb 4v t stg storage temperature range -40 105 c t op operating ambient temperature -25 70 c t op1 operating ambient temperature with current derating -25 85 c typ e ordering number output voltage [v] input voltage [v] output ripple [mvpp] efficiency [%] notes
3/8 GS-R12HXXX2 connection diagram and mechanical data pin description pin function description 1 input gnd return for input voltage source 2 input gnd return for input voltage source 3 input gnd return for input voltage source 4 input + dc input voltage 5 input + dc input voltage 6 input + dc input voltage 7 input + dc input voltage 8v ref 3.3v reference voltage 9 inh a logical level (active high) disables the device, when it is open an internal pull up disables the device 10 sync master/slave synchronization 11 fb feedback input, available on adjustable device 12 v out regulated output 13 v out regulated output
GS-R12HXXX2 4/8 electrical characteristics all versions (t amb =25 ) c, unless otherwise specified.) electrical characteristics for GS-R12HXXX2 only (t amb =25 ) c, unless otherwise specified.) 14 v out regulated output 15 v out regulated output 16 output gnd return for output voltage 17 output gnd return for output voltage 18 output gnd return for output voltage symbol parameter test condition min. typ. max. unit temperature stability v i =v o + 1.5v i o = 2a mv/c i ol current limit v i =4.5 15v 2.5 a i q quiescent current v i =12v i o = 0a 1.8 2.5 ma i qst-by total stand-by quiescent current v inh >2.2v 50 100 a f s switching frequency v i =12v i o = 1.5a 225 250 275 khz v ref reference voltage v i =4.5 15v i ref =0 5ma 3.234 3.3 3.366 v short circuit current 8 10 30 ma inh inh threshold voltage device on 0.8 v device off 2.2 v v fb feedback voltage v i =4.5 15v i o = 0 2a 1.22 1.235 1.25 v srv supply voltage rejection mv/v r th thermal resistance case to ambient c/w symbol parameter test condition min. typ. max. unit i o output current v i =4.5 15v 02a v r ripple voltage v i =12v i o = 2a 20 mvpp pin function description
5/8 GS-R12HXXX2 electrical characteristics for gs-r24hxxx only (t amb =25 ) c, unless otherwise specified.) user notes input voltage the recommended operating maximum dc input voltage is 15v inclusive of ripple voltage. reference voltage no capacitor is required for stab ility. inhibit function the inhibit feature allows to put in stand-by mode the device. with inh pin 9 higher than 2.2v the device is disabled and the power consumption is reduced to less than 100 a. 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 v cc compatible. multiple units synchronization using more than one unit on the same circuit, it is possible to synchronize the switching frequency, connecting all pin 10 together (see figure 3). the unit with higher frequency becomes the master. 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 suf- ficiently low duty cycle at 250 hz, the output current, in strong overcurrent or short circuit conditions, could in- crease again. for this reason the switching frequency is also reduced, so keeping the inductor current under its maximum threshold. symbol parameter test condition min. typ. max. unit i o output current v i =16 35v for gs-r24h0332 --------------------- gs-r24h0502 02a i o output current v i =16 35v for gs-r24h1201.5 0 1.5 a i o output current v i =16 35v for gs-rh0001 0 1-2 a v r ripple voltage v i =24v i o = 2a for gs-r24h0332 --------------------- - gs-r24h0502 20 mvpp v r ripple voltage v i =24v i o = 2a for gs-r24h1201.5 100 mvpp v r ripple voltage v i =24v i o = 2a for gs-r24h0001 100- 250 mvpp
GS-R12HXXX2 6/8 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 20 oc avoids that the devices turns on and off continuously. thermal characteristics output voltage programming (gs-r12h0002 only) the gs-r12h0002 output voltage is 5.05v 4%, to reduce this value connect a resistor between pin 11 (fb) and pin 12 (v out ). 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=[(v out -1.235)*10.2]/(5.05-v out ) -- [k ohm] v out can be adjusted between 1.235v (rv=0 ohm) and 5.05v (rv=open) loop compensation (gs-r12h0002 only) if required by particular load conditions, it is possible to change the feedback loop compensation, adding an ex- ternal capacitor between pin 11 (fb) and pin 12 (v out ), 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.
7/8 GS-R12HXXX2 figure 3 figure 1 figure 2
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