UCC20520: UCC20520

Hi Lakmal,

1. What is the topology and application for use of UCC20520?
2. What MOSFET, IGBT, or other load is being driven by the gate driver?
3. Can you please provide a schematic of the system under test?

When the output is oscillating, this can be for a number of reasons:

• Disable pin noise. When the disable pin is left floating or is driven by a high-impedance source such as a distant microcontroller or a large pull-down resistor, under high-noise conditions the outputs may be disabled unexpectedly due to disable pin noise. Does the OUTB oscillation continue when the disable pin is tied to GND? 
• Input pin noise with dead time. When the PWM pin sees noise, the input may be falsely triggering for short pulses which do not appear on OUTA due to dead time. Check the PWM pin for noise exceeding the threshold values for OUTA turn-on. If not already present, consider adding a small input filter per the datasheet section 9.2.2.1.
• dv/dt exceeding CMTI. During high-dv/dt, beyond the minimum guaranteed 100V/ns, high outputs may be temporarily brought low. Normally this output glitch should only last 10-15ns, but this may be enough in some systems to trigger another high dv/dt event, which can cause the oscillation observed.
• Intermittent electrical contact with VDDB, OUTB, or the probe. This is rare, but please double-check all connections are securely soldered and the probe is making solid electrical contact.

Regards,