3964

DUAL FULL-BRIDGE

PWM MOTOR DRIVER

If desired, the reference input voltage can be filtered

dent from the high-current power-ground trace to avoid

Thermal Considerations. For reliable operation, it is

recommended that the maximum junction temperature be

kept below 110

°C to 125°C. The junction temperature can

be measured best by attaching a thermocouple to the

power tab/batwing of the device and measuring the tab

approximated by using the formula:

approximately 6

°C/W for both package styles.

The power dissipation of the batwing packages can be

improved by 20 to 30% by adding a section of printed

circuit board copper (typically 6 to 18 square centimeters)

connected to the batwing terminals of the device.

The thermal performance in applications that run at

high load currents and/or high duty cycles can be im-

proved by adding external diodes from each output to

ground in parallel with the internal diodes. Fast-recovery

(

≤200 ns) diodes should be used to minimize switching

losses.

with an electrolytic capacitor (

≥47 µF is recommended)

placed as close to the device as is physically practical.

To minimize the effect of system ground IR drops on the

logic and reference input signals the system ground should

have a low-resistance return to the load supply voltage.

See also “Current Sensing” and “Thermal Consider-

ations” above.

switching losses will decrease, low-level load current

regulation will improve, EMI will be reduced, the PWM

frequency will decrease, and ripple current will increase.

parameters. For applications where audible noise is a

range of 15 to 35

µs.