TL431: TL431AIDBZR related issues

jeno.zhang

Part Number: TL431

The TL431AIDBZR circuit is shown below, with a designed output of 5V and an actual output of 2.6V. Please help analyze the cause and determine if there is an issue with the resistor configuration？

Thanks！

8 months ago

0 Walter Zollinger 8 months ago

TI__Expert 7180 points

Hello,

The 1.1uF load capacitance is in the unstable region of this device. This might be affecting the output voltage. Please remove or modify the capacitance values to be outside of the B curve. The resistor values should be fine.

Thanks,

Walter

0 jeno.zhang 8 months ago in reply to Walter Zollinger

Expert 2315 points

hello，

Customer feedback: C82 and C83 are not soldered, only resistors, with an output voltage of 2.6V. Please help analyze if there are any other reasons? thanks！

0 Walter Zollinger 8 months ago in reply to jeno.zhang

TI__Expert 7180 points

Hello,

What is the load current draw on the VR5V rail? The device may not be receiving enough current.

Thanks,

Walter

0 jeno.zhang 8 months ago in reply to Walter Zollinger

Expert 2315 points

Hello，

Under no-load condition, the output voltage is 2.6V.

Is there any other possible reason?

0 Walter Zollinger 8 months ago in reply to jeno.zhang

TI__Expert 7180 points

Hello,

The input is a steady 12V? Have you tried swapping other TL431 parts?

Thanks,

Walter

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TL431: TL431AIDBZR related issues