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TLV6710: Can I connect TLV6710 VDD to 40V and pull up OUT to VDD=40V?

user5350137
Intellectual 520 points
Part Number: TLV6710
Other Parts Discussed in Thread: TL431, TLV1805

Hi Experts,

I want to use a comparator device with high supply voltage, my supply voltage is 40V, but the maximum supply voltage of TI comparators is 36V, the device is TLV6710.

So can I connect my 40V power supply to TLV6710 VDD? If not, can I use a external resistor divider network to divide 40V to 36V, then connect to TLV6710 VDD? Is there any risk in this method?

Also, can I pull up TLV6710 OUT to this 40V VDD? If not, can I pull up OUT to the 36VDD, which is divided from 40V by resistors?

Thank you!

Rachel

  • 0
    Guru 140200 points

    Hi Rachel,

    how much supply current is the additional circuitry allowed to draw? And what pull-up resistors do you want to mount?

    A resistor voltage divider is possible. You would need to put a decoupling cap in parallel to the lower resistor, though. The usual method to reduce the supply voltage would be a zener diode in combination with a current limiting resistor. There are low current zener diodes available for this purpose. But again, it depends on how much supply current may flow in your application.

    Kai

  • 0 in reply to kai klaas69
    TI__Mastermind 24560 points

    Rachel

    Since the TLV6710 is an open-drain device, the quiescent current for the device is relatively constant.  So using a resistor divider to reduce the power supply voltage for the TLV6710 is reasonable.  I suggest you put a de-coupling capacitor from the supply pin to ground of the TLV6710 to handle any transient current spikes when the output transitions. 

    However, the resistor divider is not well suited for being the pull-up voltage for your output.  The current changes dramatically when the output goes low, so that would disrupt a resistor divider network potentially.  I assume you need to level shift the output of the TLV6710 to drive whatever is connected to the output.  You should be able to use the power supply of whatever is being driven to be the pullup up voltage for the external pullup resistor. 

    If for some reason you need the output of the comparator to swing to high voltages, say 40V, I suggest you switch to using a TLV1805 which can be powered directly from the 40V supply and use a resistor divider or a shunt reference such as the TL431 to be your switching threshold.  This may greatly simplify your circuit switching to this comparator if you do not need to level shift the output voltage to a lower supply level.

    Chuck