TLE2426: TLE2426 is sufficient for supply 8 of Opamp(OPA1637) VOCM?

Younggi Jung

Prodigy 100 points

Part Number: TLE2426
Other Parts Discussed in Thread: OPA1637

Hello I am Jung

I am using TLE2426 for DAC to supply 8pcs of OPA1637 for VOCM.(Mid bias)

I found a problem which is the output of TLE2426 is only 0.7V.(I expected 2.5V because input voltage is 5V)

However, ADC part of TLE2426 that is operating 4 pcs of OPA1637 output 2.5v fine.

I am not sure DAC part of TLE2426 is failure or TLE2426 cannot supply 8 pcs of VOCM of Opamp.

Could you please advice for me?

over 3 years ago

0 Michael Steffes over 3 years ago

Guru 48395 points

Looks like that input pin would be 2.5Mohm to mid supply, so if the supplies are balanced +/- and there are 8 of them, that is an effective load of 375kohm to ground. So check your desired Vocm to get the required current vs what the TLC2426 can supply

0 Chris Featherstone over 3 years ago

TI__Mastermind 25210 points

Jung,

I have simulated the TLE2426 driving the VOCM pin of 8 OPA1637 devices. I do not see any obvious issue yet. The current required from the TLE2426 appears to be 8.12uA. Have you attempted to disconnect 4 OPA1637 devices from the DAC section to see if the issue resolves? Are you able to monitor pin 1 with an oscilloscope to see if the device is stable with all 8 devices connected?

0 kai klaas69 over 3 years ago

Guru 140200 points

Hi Jung,

can you show a schematic?

Kai

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TLE2426: TLE2426 is sufficient for supply 8 of Opamp(OPA1637) VOCM?