The DS3668 quad peripheral driver is designed for those applications where low operating power, high breakdown voltage, high output current and low output ON voltage are required. Unlike most peripheral drivers available, a unique fault protected circuit is incorporated on each output. When the load current exceeds 1.0A (approximately) on any output for more than a built-in delay time, nominally 12 µs, that output will be shut off by its protection circuitry with no effect on other outputs. This condition will prevail until that protection circuitry is reset by toggling the corresponding input or the enable pin low for at least 1.0 µs. This built-in delay is provided to ensure that the protection circuitry is not triggered by turn-on surge currents associated with certain kinds of loads.
The DS3668"s inputs combine TTL compatibility with high input impedance. In fact, its extreme low input current allows it to be driven directly by a MOS device. The outputs are capable of sinking 600 mA each and offer a 70V breakdown. However, for inductive loads the output should be clamped to 35V or less to avoid latch up during turn off (inductive fly-back protection - refer AN-213). An on-chip clamp diode capable of handling 800 mA is provided at each output for this purpose. In addition, the DS3668 incorporates circuitry that guarantees glitch-free power up or down operation and a fail-safe feature which puts the output in a high impedance state when the input is open.
The molded package is specifically constructed to allow increased power dissipation over conventional packages. The four ground pins are directly connected to the device chip with a special copper lead frame. When the quad driver is soldered into a PC board, the power rating of the device improves significantly.
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Output fault protection
High impedance TTL compatible inputs
High output current-600 mA per output
No output latch-up at 35V
Low output ON voltage (550 mV typ @ 600 mA)
High breakdown voltage (70V)
Open collector outputs
Output clamp diodes for inductive fly-back protection
NPN inputs for minimal input currents (1 µA typical)
