UCC2894: Practical Maximum Operating Temperature

Satyajeet Deshmukh

Part Number: UCC2894
Other Parts Discussed in Thread: UCC2891, UCC28C42-Q1, UCC28C52-Q1

Hello, I am trying to design an active clamp flyback with UCC2894D for an automotive application. The temperature requirement is 105 degC. According to the data given in the datasheet, the device supports this temperature although the TI website states the max operating temperature as 85 degC. I also checked the Failures in Time (FIT) rates data to be using 115 degC for testing.

Please let me know if I can safely use this device at 105 degC?

over 1 year ago

+1 Steven Mappus1 over 1 year ago

TI__Mastermind 24795 points

Satyajeet,

The max operating temperature for UCC2894 is -40°C<Tamb<+85°C. The max recommended junction temperature you see in the data sheet is -40°C<Tj<105°C and this is not the same as the -40°C<Tamb<+85°C you referenced. Operating the UCC2894 above +85C violates the data sheet and is not recommended. Also, UCC2891/2/3/4/7 family of active clamp PWM controllers are not available in -Q1 (not automotive qualified controllers).

Thanks for connecting through E2E.

Regards,

Steve M

0 Satyajeet Deshmukh over 1 year ago in reply to Steven Mappus1

Prodigy 30 points

Thank you for your prompt response. Can you suggest a automotive qualified controller for controlling the active clamp flyback for continuous current mode?

0 Satyajeet Deshmukh over 1 year ago in reply to Steven Mappus1

Prodigy 30 points

Also I was referring to this when I mentioned the 125 in datasheet.

0 Steven Mappus1 over 1 year ago in reply to Satyajeet Deshmukh

TI__Mastermind 24795 points

Satyajeet,

I guess I would ask: why active clamp for automotive? Are you planning for power conversion from the low-voltage (LV) side or high-voltage (HV) side? If LV side, there is little benefit from active clamp ZVS. If HV side, the internal start-up can't be used and there are no p-channel MOSFETs rated for EV HV. For LV conversion, TI has UCC28C42-Q1 and for HV conversion we offer UCC28C52-Q1. Both are general purpose PWM controllers that do not include active clamp but are fully AEC-Q100 automotive qualified controllers well suited for CCM or DCM flyback and forward topologies.

For whatever your input/output electrical requirements are, you might consider to download TI Power Stage Designer and you can compare the benefits between different topologies.

Regards,

Steve M

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UCC2894: Practical Maximum Operating Temperature