A2557ELBTR

A2557 Protected Quad Driver with Fault Detection and Sleep Mode Features and Benefits Description ▪ 300 mA output current per channel ▪ Independent overcurrent protection and thermal limiting for each driver ▪ Output voltage to 60 V ▪ Output SOA protection ▪ Fault-detection circuitry for open or shorted load ▪ Low quiescent current Sleep Mode ▪ Integral output flyback/clamp diodes ▪ TTL- and 5 V CMOS-compatible inputs The A2557 has been specifically designed to provide costeffective solutions to relay-driving applications with up to 300 mA drive current per channel. They may also be used for driving incandescent lamps in applications where turn-on time is not a concern. Each of the four outputs will sink 300 mA in the on state. The outputs have a minimum breakdown voltage of 60 V and a sustaining voltage of 40 V. A low-power Sleep Mode is activated with either ENABLE low or all inputs low. In this mode, the supply current drops to below 100 μA. Packages: Package B, 16-pin DIP with exposed tabs Not to scale Package EB, 28-pin PLCC with internally fused pins Overcurrent protection for each channel has been designed into these devices and is activated at a nominal 500 mA. It protects each output from short circuits with supply voltages up to 32 V. When an output experiences a short circuit, the output current is limited at the 500 mA current clamp. In addition, foldback circuitry decreases the current limit if an excessive voltage is present across the output and assists in keeping the device within its SOA (safe operating area). An exclusive-OR circuit compares the input and output state of each driver. If either a short or open load condition is detected, a single FAULT output is turned on (active low). Continued on the next page… Package LB, 16-pin SOIC with internally fused pins Functional Block Diagram FAULT ENABLE SLEEP CONTROL 60 A K COMMON CONTROL ONE OF FOUR DRIVERS V CC – 2.5 V + OUTN IN N THERMAL LIMIT CURRENT LIMIT 30 A