L4974A STMicroelectronics

L4974A 3.5A SWITCHING REGULATOR . 3.5A OUTPUT CURRENT MULTIPOWER BCD TECHNOLOGY . 5.1V TO 40V OUTPUT VOLTAGE RANGE . 0 TO 90% DUTY CYCLE RANGE . INTERNAL FEED-FORWARD LINE REG INTERNAL CURRENT LIMITING . PRECISE 5.1V 2% ON CHIP REFERENCE . RESET AND POWER FAIL FUNCTIONS . INPUT/OUTPUT SYNC PIN .UNDER VOLTAGE LOCK OUT WITH HYS- TERETIC TURN-ON . PWM LATCH FOR SINGLE PULSE PER PE- POWERDIP (16 + 2 + 2) RIOD . VERY HIGH EFFICIENCY . SWITCHING FREQUENCY UP TO 200KHz ORDERING NUMBER : L4974A . THERMAL SHUTDOWN . CONTINUOUS MODE OPERATION the L4974A include reset and power fail for micro- DESCRIPTION processors, feed forward line regulation, soft start, The L4974A is a stepdown monolithic power switch- limiting current and thermal protection. The device ing regulator delivering 3.5A at a voltage variable is mounted in a Powerdip 16 + 2 + 2 plastic package from 5.1 to 40V. and requires few external components. Efficient Realized with BCD mixed technology, the device operation at switching frequencies up to 200KHz uses a DMOS output transistor to obtain very high allows reduction in the size and cost of external filter efficiency and very fast switching times. Features of component. BLOCK DIAGRAM 1/22 June 2000 This is advanced information on a new product now in development or undergoing evaluation. Details are subject to change without notice.L4974A ABSOLUTE MAXIMUM RATINGS Symbol Parameter Value Unit V Input Voltage 55 V 11 V Input Operating Voltage 50 V 11 V Output DC Voltage -1 V 20 Output Peak Voltage at t = 0.1s f = 200khz -5 V I Maximum Output Current Internally Limited 20 V Boostrap Voltage 65 V I Boostrap Operating Voltage V + 15 V 11 V , V Input Voltage at Pins 4, 12 12 V 4 8 V3 Reset Output Voltage 50 V I Reset Output Sink Current 50 mA 3 V , V , V , V Input Voltage at Pin 2, 7, 9, 10 7 V 2 7 9 10 I Reset Delay Sink Current 30 mA 2 I Error Amplifier Output Sink Current 1 A 7 I Soft Start Sink Current 30 mA 8 P Total Power Dissipation at T 90C 5 W tot PINS at T = 70C (No copper area on PCB) 1.3 W amb T , T Junction and Storage Temperature -40 to 150 C J stg PIN CONNECTION (top view) THERMAL DATA Symbol Parameter Value Unit R Thermal Resistance Junction-Pins max 12 C/W th j-pins R Thermal Resistance Junction-ambient max 60 C/W th j-amb 2/22