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TLV2197-Q1: The chip is damaged when customer inversely connected VCC to GND and GND to VCC

Zirui Su
Expert 5340 points
Part Number: TLV2197-Q1


Hi team 

I would like to ask a question that :

Customer used TLV2197Q1 to make a low-pass filter (attachment)， the amplitude of voltage supply is 14V

信号转换器_功能框图.pdf

and now customer reversed the KL15 pin power supply pin of the op amp to ground (the PWM input remains unchanged), and the op amp burns up immediately. What may cause this issue?

  • 0
    Guru 140200 points

    Hi Zirui,

    when reversely connecting the supply voltage of an OPAmp an internal die's pn-junction becomes forward biased. Because of this, the supply voltage gets short-circuited and a short-circuit current runs through the die. Unless the short-circuit current is current limited to a sane level within the supply voltage generator, the chip gets barbecued and destroyed.

    You may want to insert a series diode into the supply voltage line to avoid a high current flow in the case the supply voltage is reversely connected.

    Kai

  • 0
    TI__Guru* 93105 points

    Hi Zirui,

    Adding a little to Kai's comments. That normally OFF substrate diode will draw hundreds of milliamperes, if not amperes of current if the supplies become reversed. The power dissipation capability of the diode is rapidly exceeded and the temperature rises tremendously until the silicon melts and the IC structures are destroyed.

    The net result is often a direct short between the op amp supply pins after the silicon has re-solidified, or in some cases an open circuit occurs due to an internal bond wire opening. In any case, a supply reversal must be completely avoided unless a supply line protection diode is added to the circuit as Kai has suggested.

    Regards, Thomas

    Precision Amplifiers Applications Engineering