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LMC6042: opamps with I_supply <20uA, Vdd > 24V, input CMV including ground

Nitish Agrawal
Expert 1565 points
Part Number: LMC6042
Other Parts Discussed in Thread: TLV27L2, TLV27L1, TLV2401, TLV2381, TLV2252, TLV2451

Hello,

I am looking for other op-amps like LMC6042 with following requirements:

1)  10uA-20uA supply current

2)  Vcc up to 26V

3)  Input common mode voltage must include negative supply or ground.

4)  Price range of $1.00 in 1000pc. qty.

Following are some op-amps I found.

LMC6042 but it has slightly higher I_supply than my target.

LMC6462, but its operation appears to be ensured at 5V (per datasheet) even though Vsupply = 15V total.

OPA251, but its I_supply is higher than my target (and cost is higher too).

Any suggestions would be greatly appreciated.  The request is urgent.

Kind regards,

Nitish Agrawal

  • 0
    TI__Mastermind 30600 points
    Hi Nitish,

    In the general purpose space, your set of specs is going to be hard to meet. You say that you need up to 26V VCC and then in one of your part comments you say that Vsupply = 15V.

    Could you also comment on what your desired GBW and channel count are?

    Some other devices you might consider:
    TLV27L1, TLV27L2
    TLV2401
    TLV2381

    I've alerted the Low Power team, they may be able to provide some comment as well.

    Best,
    Paul
  • 0 in reply to Paul Goedeke
    TI__Mastermind 24340 points

    Nitish

    I agree with everything Paul mentioned.  We do not have a device that meets all of your criteria.  So can you help us understand a little more about your application circuit?  Maybe we can help with some of the tradeoffs.  You did mention that the common mode voltage is close to ground and I presume this is a single supply application.  if the common mode is close to ground, what is driving your need for 26V operating voltage.  Is it for protection against high voltage spikes or is the supply in your system in the 20V range?  Or do you need high voltage swing at the amplifier output.  If you can share a little about what you are driving with the output of the amplifier that would be good to know.  Since the system you are describing needs low power consumption, you can consider powering your amplifier with a GPIO pin from a uC or ASIC in your system if you do not really need high voltage swing from the amplifier.  When amplifiers are low power, this is a common practice.  I wrote about this topic for the personal electronic space if you are interested in reading.  Here is a link Chuck

  • 0 in reply to Chuck Sins
    Expert 1565 points
    Hi Chuck and Paul,

    Thank you for responding.
    I have two separate systems I am using these op-amps in (nominally, 12V and 24V). Due to some system aspects, the op-amp ground pin can be 200mV below its negative supply.
    The op-amp will be controlling some background process when the unit is not powered on....so, the main MCU is not alive, hence, no access to the GPIO bus....that was a good suggestion.
    The opamps are going to drive some comparators and MOSFETs...so current sourcing requirement is not much. In one case, I might drive a relay coil...but not certain about that yet.

    Desired gain bandwidth is low...20kHz or lower is fine. Channel count of 1 or 2.

    Thank you for suggesting TLV27L1, TLV2401, TLV2381...they should work great in the 12V system.

    Kind regards,
    Nitish Agrawal
  • 0 in reply to Nitish Agrawal
    Expert 1565 points
    Hello Paul and Chuck,

    Are there Spice models available for TLV2381 and TLV27L1? I couldn't find them on TI's website.

    Kind regards,
    Nitish
  • 0 in reply to Nitish Agrawal
    TI__Mastermind 30600 points
    Hi Nitish,

    You are correct that neither of those devices have models available right now, my apologies. What type of simulation are looking to perform? You may consider using either the TLV2252 or the TLV2451 models as substitutes for the real devices.

    Best,
    Paul