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2V7 logic to open drain with 12V,24V,40V

richard payne
Genius 4640 points
Other Parts Discussed in Thread: SN75471

I'm looking for device with following requirements

(1) Low power (nanowatts)

(2) SOT23 or SOT70 package or similar

(3) 125C/150C Grade

(4) Open drain output with voltage up to 12, 24, 40 or 60V

(5) Minimum external parts.

(6) Stable threshold for 2V7 logic signal (ie MSP430).

(7) Drain current from few mA to 50mA.It used to pull signal to LOW to shutdown the switching PSU

It sound like comparator but need bias voltage to set threshold to match 2V7 Logic

The issue with 2N7006K NMOS that the threshold drift over temp from -40C to 150C which device may not function correctly. 

I had a look in TI website but could not find solution. 

  • 0
    Guru 317370 points

    "2N7006K"? Your other question mentions 2N7002K.

    Anyway, just use any random MOSFET with a lower threshold voltage, e.g., many BSS138 models have VDS(max) 60 V, or use BSS139 for really high voltages.

    (TI makes power MOSFETS, which are measured in A, not mA.)

  • 0
    TI__Prodigy 60 points
    Hi Richard,

    please use our parametric search at the link below, to find the right comparator based on your needs

    www.ti.com/.../products.html

    thanks Tushar
  • 0 in reply to Tushar Jog
    TI__Genius 14317 points

    Hello Richard,

    One approach might be to use a logic interfaced Darlington Driver device like the SN75471 or make your own Darlington Driver using discrete NPN transistors. A voltage divider on the input of a MOSFET might also work.

  • 0 in reply to Jeffery Pfarr
    Genius 4640 points
    Thank for trying, I found suitable MOSFET for now.

    Penny fr thought.....I believe there missing gap in market, a single gate (or dual gate) low voltage GPIO input (based on 74LVC, buffer or NAND) with high voltage open drains (up to 100mA, 60V). This give much more stable threshold over temp than discrete MOSFET (-55C to 150C). SOT23/SOT70 package or similar QFN.

    I have recently reduced 3V3 to 2V7 for MCU and later on 2V5. More modern IC no longer work on 3V3 system and moving away from +5V to lower voltage (ie AD7988-1, AD2174, etc).

    R.