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TLV3202-Q1: TLV3202 Damage

Part Number: TLV3202-Q1
Other Parts Discussed in Thread: TLV3202, TLV9032, TLV7032, LM393LV

Hi

below is the circuit, during test, TLV3202 is easy to be damaged, mainly focus on pin 3, when pin 7 output 5V, pin 3 is 1.69V or 3.72V,  it is 5V for good board.

please help to check, thanks

  • Hi Jian,

    C1013 might have enough potential to damage U933A during power down. I would add a diode clamp as shown in figure 26 of datasheet or at least a suited current limiting resistor in front of pin 3. Limit the current to well below 10mA.

    Kai

  • yes, i agree with u, but according the datasheet,  1k resistor and clamp diodes has been integrated in the device, 1k resistor can limit the current below 5mA, 

    that's why i don't understand, but i will add a 10k resistor in front of pin3 for further protection.

    thanks

  • i add a 100k resistor in front of pin3, the problem is same, when i power up/down several times, the device is damaged. 

  • Hello Jian,

    Seems that the first sentence is not too clear. The internal resistors are AFTER the ESD clamp diodes and before the internal differential clamp.

    The ESD diodes are connected directly between the input and supplies, seeing the full current.

    The last sentence states "the addition of external bypass diodes and resistors is recommended, as shown in Figure 26". They are suggesting the use of external resistor and clamp diodes. Perhaps the "Core" and title of Fig 26 are not helpful...

    As Kai surmised, the large (10uF) cap directly on the input is capable of dumping large peak currents into the pins, particularly if the supply goes down quickly. The capacitor can also back-feed the 5V supply through the ESD diode for a short period after power down, possibly exceeding the 10mA Abs Max.

    I would recommend adding a 5k series resistor (1k per volt) between the input pin 3 and the capacitor node and see if the problem persists. You can try lifting the 10uF cap and placing the resistor in series with the cap as an experiment. If that does not solve the issue, then look for transients on all the pins during power-up and power-down.

    You can also try the TLV7032, LM393LV or TLV9032 which have new  fault-tolerant inputs, which do not have upper ESD clamps and can go up to 5V regardless of the supply voltage (even 0V). They are a little slower than the TLV3202, but with a 100k and 10uF time constant, the speed difference does not seem to be an issue.

  • Hi Jian,

    does it work now?

    Kai

  • Hi Kai

    It's still in test now, can you help to confirm if there is current limited resistor and clamping diodes inside of TLV3202? Thanks

  • Hello Jian,

    The TLV3202 does NOT have a resistor between the input pin and the ESD structure.

    It is just like this:

    The 1K resistor mentioned in the paragraph is on the right-hand  "Internal Circuitry" side facing a second internal clamp. These internal resistors after the ESD diodes are common and help further dissipate any ESD strikes that get past the diodes. Normally you do not see them.

    The ESD diodes are DIRECTLY connected to the pins. AN EXTERNAL CURRENT LIMITING RESISTOR IS REQUIRED.

    My rule-of-thumb is 1k ohm per volt of expected over-voltage. So if you are expecting 5V,  then a 5k minimum resistor is recommended.

    The Figure 26 title should really be "Recommended External Protection" or similar...it seems to be causing a confusion.

  • Ok,Understood.

    Thanks

  • Hi Paul

    It is a pity that TLV9032 doesn't have VSSOP8 footprint, basically SOIC8 and VSSOP8 are common in amplifier or comparator. why TLV9032 only has SOIC8.

    thanks

  • Hello Jian,

    See the "Device Information"  table on the front page of the TLV9032 datasheet. This table shows all the planned package options, which includes the VSSOP-8. The SOIC8 was first due to popularity.

    Because of the large amount of device and package options, and only so many release resources, the package releases are staggered and spaced out through the next few months as they become available.

    If you are interested in the TLV9032, I can put you in contact with sales to get VSSOP samples when they are available.


  • OK, got it. thanks.

    They can reach me by email, wangjianD@changguangxi.com. thanks again.