The TC4404/TC4405 are CMOS buffer-drivers
constructed with complementary MOS outputs, where
the drains of the totem-pole output have been left
separated so that individual connections can be made
to the pull-up and pull-down sections of the output. This
allows the insertion of drain-current-limiting resistors in
the pull-up and/or pull-down sections, allowing the user
to define the rates of rise and fall for a capacitive load;
or a reduced output swing, if driving a resistive load, or
to limit base current, when driving a bipolar transistor.
Minimum rise and fall times, with no resistors, will be
less than 30 nsec for a 1000 pF load.
For driving MOSFETs in motor-control applications,
where slow-ON/fast-OFF operation is desired, these
devices are superior to the previously used technique
of adding a diode-resistor combination between the
driver output and the MOSFET, because they allow
accurate control of turn-ON, while maintaining fast turn-
OFF and maximum noise immunity for an OFF device.
When used to drive bipolar transistors, these drivers
maintain the high speeds common to other Microchip
drivers. They allow insertion of a base current-limiting
resistor, while providing a separate half-output for fast
turn-OFF. By proper positioning of the resistor, either
npn or pnp transistors can be driven.
For driving many loads in low-power regimes, these
drivers, because they eliminate shoot-through currents
in the output stage, require significantly less power at
higher frequencies, and can be helpful in meeting
low-power budgets.