L497 Datasheet | STMicroelectronics

DESCRIPTION The L497is an integratedelectronicignition controller for breakerless ignition systemsusing Hall effect sensors. BLOCK DIAGRAM The device drives an NPN external darlington to control the coil current providingthe required stored energy with low dissipation. A special feature of the L497 is the programmable time for the recovery of the correct dwell ratio Td/T when the coil peak current fails to reach 94 % of the nominal value. In this way only one spark may have an energy less than 94 % of the nominal one during fast acceleration or cold starts. March 1998 1/11 ABSOLUTE MAXIMUM RATINGS Symbol I3 V3 V6 I16 V16 I7 I15 Parameter D.C. Supply current Transient Supply Current (tf fall time constant = 100ms) Supply Voltage RPM Voltage D.C. Driver Collector Current Pulse ” ”(t <= 3ms) Driver Collector Voltage Auxiliary Zener Current D.C. Overvoltage Zener Current Pulse ” ” t fall = 300µs, trep Repetition Time > = 3ms Reverse Battery Voltage if Application Circuit of Fig. 4 is used Junction and Storage Temperature Range Power Dissipation at Taluminia = 90 °C for SO-16 Tamb = 90 °C for DIP-16 Value 200 800 Int. Limited to Vz3 28 300 600 28 40 15 35 - 16 - 55 to 150 1.2 0.65 V m A m A V m A m A m A V °C W W Unit m A m A VR Tj, Tstg Ptot PIN CONNECTION (top view) THERMAL DATA Symbol Parameter Max Max Value 90 50 Unit °C/W °C/W Thermal Resistance Junction-ambient for DIP-16 Rth j-amb R th j-alumin (- ) Thermal Resistance Junction-alumina for SO-16 (- ) Thermal resistance junction-aluminia wi th the device soldered on the mi ddle of an aluminia supporting substrate mesuri ng 15 x 20 ; 0.65 mm thickness. 2/11 PIN FUNCTIONS (refer to fig. 4) N° 1 2 3 Name GND SIGNAL GND POWER SUPPLY Function This pin must be connected to ground. This pin must be connected to ground. Supply Voltage Input. An internal 7.5 V (typ) zener zener limits the voltage at this pin. The external resistor R5 limits the current through the zener for high supply voltages. This pin must be...