TLV3012: outputs glitch/spur during slow power up

Jerry Chen

Part Number: TLV3012

Hi there,

Below is the schematic and waveform of TLV3012. Blue is 3.3V power supply, yellow is REG20_VOUT input to IN+, green is OUT. It seems, if the power up slope is slow, TLV3012 would output some glitch/spur in the output. Do we have any P2P substitution which doesn't have this operation?

Thanks.

over 4 years ago

0 Chuck Sins over 4 years ago

TI__Mastermind 24290 points

Jerry

I’m familiar with what you’re observing. Unfortunately the tlv3012 has something in its startup sequence that causes that glitch. Unfortunately I do not have anything that is pin compatible but our tlv4041r1 is functionally similar and does not suffer from this startup glitch since it has a POR circuit that controls the comparator output as the supply ramps up. In this device, the output is held low until power reaches the operating range. By next year the tlv4041r1 will also be available in a SOT23 package but for now you can evaluate on our little EVM which is a DIP breakout board that is easy to prototype with.

Chuck

0 Jerry Chen over 4 years ago in reply to Chuck Sins

TI__Expert 5110 points

Hi Chuck,

Is there any way to reduce it? Increase the rising edge slope of the power supply?

Thanks.

0 Chuck Sins over 4 years ago in reply to Jerry Chen

TI__Mastermind 24290 points

Jerry

From my recollection, it was always about 6us wide regardless of ramp rate. It was just easier to capture when the ramp rate was slower.

Chuck

0 kai klaas69 over 4 years ago in reply to Chuck Sins

Guru 140200 points

This strange behaviour should be mentioned in the datasheet, I think.

Kai

0 Chuck Sins over 4 years ago in reply to kai klaas69

TI__Mastermind 24290 points

That's a fair suggestion, we will consider adding that on our next revision of the datasheet. For most applications, the glitch is occurring outside of the recommended operating voltage range. While it is true that we have noticed this behavior, we do not have extensive data that characterizes this startup behavior. The main reason for adding the content would be to prevent someone from using this device in applications that require a known startup condition that can only come from devices such as TLV70x1 and TLV40x1 that have an integrated power on reset circuit.

Chuck

0 kai klaas69 over 4 years ago in reply to Chuck Sins

Guru 140200 points

Hi Chuck,

I wouldn't characterize or specify the glitch, but only mention that a glitch can occur during power-up in certain situations. Then the designer is warned and will not run into unpleasant surprise.

Kai

0 Chuck Sins over 4 years ago in reply to kai klaas69

TI__Mastermind 24290 points

Fair suggestion.

thanks Kai

Chuck

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TLV3012: outputs glitch/spur during slow power up