L4974A Datasheet | STMicroelectronics

DESCRIPTION The L4974Aisa stepdownmonolithicpower switching regulator delivering 3.5A at a voltage variable from 5.1 to 40V. Realized with BCD mixed technology, the device uses a DMOS output transistor to obtain very high efficiency and very fast switching times. Features of BLOCK DIAGRAM the L4974A include reset and power fail for microprocessors, feed forward line regulation, soft start, limiting current and thermal protection. The device is mountedin a Powerdip16 + 2 + 2 plastic package and requires few external ponents. Efficient operation at switching frequencies up to 200KHz allows reductionin the size and cost of externalfilter ponent. June 2000 1/22 This is advanced information on a new product now in development or undergoing evaluation. Details are subject to change without notice. ABSOLUTE MAXIMUM RATINGS Symbo l V11 V11 V20 I20 VI V4 , V 8 V3 I3 V2, V 7, V 9, V10 I2 I7 I8 Ptot TJ, Tstg Input Voltage Input Operating Voltage Output DC Voltage Output Peak Voltage at t = 0.1µs f = 200khz Maximum Output Current Boostrap Voltage Boostrap Operating Voltage Input Voltage at Pins 4, 12 Reset Output Voltage Reset Output Sink Current Input Voltage at Pin 2, 7, 9, 10 Reset Delay Sink Current Error Amplifier Output Sink Current Soft Start Sink Current Total Power Dissipation at TPINS ≤ 90°C at T amb = 70°C (No copper area on PCB) Junction and Storage Temperature Parameter Valu e 55 50 -1 -5 Internally Limited 65 V11 + 15 12 50 50 7 30 1 30 5 1.3 -40 to 150 V V V V m A V m A A m A W W °C Unit V V V V PIN CONNECTION (top view) THERMAL DATA Symb ol Rth j-pins Rth j-amb Parameter Thermal Resistance Junction-Pins Thermal Resistance Junction-ambient max max Valu e 12 60 Unit °C/W °C/W 2/22 PIN FUNCTIONS No 1 2 3 4 Name BOOTSTRAP RESET DELAY RESET OUT RESET INPUT F unctio n A Cboot capacitor connected between this terminal and the output allows to drive properly the internal D-MOS transistor. A Cd capacitor connected between this terminal and ground...