• State
  • Locked Locked
  • Replies 2 replies
  • Subscribers 49 subscribers
  • Views 639 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

OPA4344 / Minimum VCM at the over temperature range

S.Satoshi
Guru 21675 points
Other Parts Discussed in Thread: OPA4344

Hi All,

Please let me ask about the minimum Common-Mode Voltage Range (VCM) at over temperature.


In the datasheet, the the minimum VCM is specified as -0.3V at only Ta=25degC, not at the over temperature range because it's not in boldface type. (See circled red)
On the other hand, the minimum VCM is -0.3V both Ta=25degC and over temperature range in the condition of CMRR. (See circled blue)

It means that the minimum VCM at the over temperature range is also -0.3V. Is my understanding correct?


Best Regards,
Sonoki / Japan Disty

  • 0
    TI__Guru 60610 points

    Sonoki,

    You are correct that the Input Common-mode Range for OPA4344 should have been shown in bold letter since it is clearly applying across the entire specified temperature range from -40C to 85C - see below:

    Having said that, you must be aware that the input bias current, IB, doubles every 10 deg C (see below a typical graph) so the maximum IB at 85 deg C might be as high as 640pA (10pA*2^6) for Vcm=Vs/2 and twice that with Vcm=(V-) - see the graph of IB vs Vcm below.  This may be important in case of using high magnitude resistor in gain network.

  • 0 in reply to Marek Lis
    Guru 21675 points

    Hi Marek,

    Thank you for your response.

    It's OK if the minimum VCMR is still -0.3V at over temperature range. The reason why our customer has cared it is they are using OPA4344 with 5V single supply operation and +IIN is below to 0V, so they concern phase reversal issue will be happened.

    Best Regards,

    Sonoki