TLV9062: Why in the simulation the input signal can be higher than V+

Hale Tan

Part Number: TLV9062
Other Parts Discussed in Thread: TLV9064

Tool/software:

Hi team,

The customer had a request with 0~1.8V input signal and inverting function circuit to output -1.8V voltage. They decided to use +1.8V and -3.3V as power supply. I make a simulation and it works.

But when I set the positive power as 0, it still works. I don't understand the reason. Could you help explain the reason?

From the datasheet, the input signal should be lower than (V+)+0.1.So when the V+ is 0, I guess that it shouldn't work. Could you help check the reason?

11 days ago

+1 Clemens Ladisch 11 days ago

Guru 281710 points

The model assumes that you are using the device correctly. It does not accurately simulate what happens in all error situations.

0 Hale Tan 11 days ago in reply to Clemens Ladisch

TI__Expert 3270 points

Hi Clemens,

Got it. Need to figure it out, so if for meeting the customer requirement, below power supply can be acceptable. Is that right?

+1 Ron Michallick 11 days ago in reply to Hale Tan

TI__Guru**** 151276 points

Hale,

The model assumes that output won't go closer than 50mV to the supply rails. This simulation limit should be current based but it is not.

In reality the output would get closer to 0V, but not all the way there.

0 Hale Tan 11 days ago in reply to Ron Michallick

TI__Expert 3270 points

Hi Ron,

thanks. Understood the simulation can't replace the actual test. So if with 0~1.8V input signal and inverting function circuit to output -1.8V voltage, the power supply railway +1.8V and -3.3V can be acceptable?

0 Clemens Ladisch 11 days ago in reply to Hale Tan

Guru 281710 points

Yes.

0 Hale Tan 9 days ago in reply to Clemens Ladisch

TI__Expert 3270 points

Hi Clemens,

By the way, if we use reference voltage which can support 10mA, as TLV9064 power supply, can TLV9064 work? About the TLV9064 load, you can think it as <1mA.

0 Clemens Ladisch 9 days ago in reply to Hale Tan

Guru 281710 points

The power supply must be able to handle I_Q plus the load current.

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TLV9062: Why in the simulation the input signal can be higher than V+