TLV4333: Output is changing on different samples.

Abhishek Kumar

Part Number: TLV4333

Tool/software:

Hi there,

I am using TLV4333 as differential amplifier to sense temperature. I have tested my circuits on few samples and found it working good on all samples. Then we went for mass production. In mass production 25/100 pieces is showing error at amplifier out put. the differential input is coming correctly to inverting and non-inverting terminal of TLV but out is not showing on 2 channels out of three being used.

can you help me find any suspected reason for it. ( the same circuit is working correctly in 75/100 systems)

I am attaching schematic for the reference.

3 months ago

0 Clemens Ladisch 3 months ago

Guru 285390 points

Unused inputs must not be left open.

What exactly do you mean with "not showing"? What are the input and output voltages?

Which channels are affected?

0 Abhishek Kumar 3 months ago in reply to Clemens Ladisch

Prodigy 30 points

Differential input voltage to amplifier is (12-22)mV , with voltage gain of 150 . Biasing voltage at Vcc is +3.3 and Gnd

By "not showing" i meant is output voltage is not showing any value although input voltages are coming.

channels 1 & 4 are affected.( This same channels are getting affected in 25/100 samples)

In one circuit I tried to connect unused pins as - Non-inverting to gnd. AND Inverting pin to output. But this also didn't solve my issue.

0 Clemens Ladisch 3 months ago in reply to Abhishek Kumar

Guru 285390 points

What are the voltages at the three I/O pins, +IN, −IN, and OUT?

0 Raymond Zhang1 3 months ago in reply to Abhishek Kumar

TI__Guru 57381 points

Hi Kumar,

The difference amplifier works per the drawing.

TLV4333 DA 09232024.TSC

Is there a possibility that the TC's polarity reversed during test? The TC has + and - polarity, typically it uses two different color code.

If you are able to measured +IN, −IN, and OUT as Clemens suggested, you will likely find the issues.

Here is the application note how to terminate unused op amp pins.

https://www.ti.com/lit/ab/sboa204a/sboa204a.pdf?ts=1727029247483

Best,

Raymond

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TLV4333: Output is changing on different samples.