SGS-Thomson L296 free download

File name L296.pdf

L296 L296P HIGH CURRENT SWITCHING REGULATORS . . . . . . . . . . . . . 4 A OUTPUT CURRENT 5.1 V TO 40 V OUTPUT VOLTAGE RANGE 0 TO 100 % DUTY CYCLE RANGE PRECISE (±2 %) ON-CHIP REFERENCE SWITCHING FREQUENCY UP TO 200 KHz VERY HIGH EFFICIENCY (UP TO 90 %) VERY FEW EXTERNAL COMPONENTS SOFT START RESET OUTPUT EXTERNAL PROGRAMMABLE LIMITING CURRENT (L296P) CONTROL CIRCUIT FOR CROWBAR SCR INPUT FOR REMOTE INHIBIT AND SYNCHRONUS PWM THERMAL SHUTDOWN Mu ltiwatt ® (15 lead) ORDERING NUMBERS : L296 (Vertical) L296HT (Horizontal) L296P (Vertical) L296PHT (Horizontal) DESCRIPTION The L296 and L296P are stepdown power switching regulators delivering 4 A at a voltage variable from 5.1 V to 40 V. Features of the devices include soft start, remote inhibit, thermal protection, a reset output for microprocessors and a PWM comparator input for synchronization in multichip configurations. The L296P incudes external programmable limiting current. PIN CONNECTION (top view) The L296 and L296P are mounted in a 15-lead Multiwatt® plastic power packageand requires very few external components. Efficient operation at switching frequencies up to 200 KHz allows a reduction in the size and cost of external filter components. A voltage sense input and SCR drive output are provided for optional crowbar overvoltage protection with an external SCR. April 1993 1/21 L296 - L296P PIN FUNCTIONS N° 1 Function Voltage Sense Input for Crowbar Overvoltage Protection. Normally connected to the feedback input thus triggering the SCR when V out exceeds nominal by 20 %. May also monitor the input and a voltage divider can be added to increase the threshold. Connected to ground when SCR not used. OUTPUT Regulator Output SUPPLY VOLTAGE Unrergulated Voltage Input. An internal Regulator Powers the L296s Internal Logic. CURRENT LIMIT A resistor connected between this terminal and ground sets the current limiter threshold. If this terminal is left unconnected the threshold is internally set (see electrical characteristics). SOFT START Soft Start Time Constant. A capacitor is connected between this terminal and ground to define the soft start time constant. This capacitor also determines the average short circuit output current. INHIBIT INPUT TTL ­ Level Remote Inhibit. A logic high level on this input disables the device. SYNC INPUT Multiple L296s are synchronized by connecting the pin 7 inputs together and omitting the oscillator RC network on all but one device. GROUND Common Ground Terminal FREQUENCY A series RC network connected between this terminal and ground determines the COMPENSATION regulation loop gain characteristics. FEEDBACK INPUT The Feedback Terminal on the Regulation Loop. The output is connected directly to this terminal for 5.1V operation ; it is connected via a divider for higher voltages. OSCILLATOR A parallel RC networki connected to this terminal determines the switching frequency. This pin must be connected to pin 7 input when the internal oscillator is used. RESET