UDN-2543B

The UDN-2543B has the following features including 1.0 A Output Current;Output Voltage to 60 V;Low Output-Saturation Voltage;Integral Output-Suppression Diodes;Efficient Input/Output Pin Structure;TTL, CMOS, PMOS, NMOS Compatible;Over-Current Protected.

Providing interface between low-level signal processing circuits and power loads to 240 W, the UDN-2543E quad power driver combines NAND logic gates and high-current bipolar outputs. Each of the four independent outputs can sink up to I A in the ON state. The outputs have a minimum breakdown voltage of 60 V and a sustaining voltage of 35 V. Inputs are compatible with most TTL, DTL, LSTTL, and 5 V CMOS and PMOS logic systems.Over-current protection has been designed into the UDN-2543B and typically occurs at 1 A. It protects the device from output short-circuits with supply voltages of up to 25 V. When the maximum driver output current is reached, that output stage is driven linearly. If the over-current condition continues, thatoutputdriver's thermal limiting will operate, limiting the driver's power dissipation and junction temperature. The outputs also include transient suppression diodes for use with inductive loads such as relays, solenoids, and do stepping motors. In display applications, the diodes can beused for the lamp-test function.The UDN-2543B is supplied in a 16-pin dual in-line plastic package with heat-sink contact tabs. The lead configuration allows easy attachment of an inexpensive heat-sink and fits a standard integrated circuit socket or a printed wiring board layout.

In the event of a shorted load, shorted winding, or stalled motor, the load current will attempt to increase. As described above, the drive current to the output stage is diverted (limiting the load current to about I A), causing the output stage to go linear. As the junction temperature of the output stage increases, the thermal limit circuit will become operational, further decreasing the drive current. The load current (junction temperature) is then a function of ambient temperature, state of remaining drivers, supply voltage, and load resistance. If the fault condition is corrected, the output driver will return to its normal saturated condition.