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Electronics => Beginners => Topic started by: 2X on May 17, 2018, 01:52:54 am

Title: Single Non Inverting Buffer With Open-Collector High-Voltage Output
Post by: 2X on May 17, 2018, 01:52:54 am

Hello,
does anyone knows if there is a single non inverting buffer with open drain/collector on chip that will takes 5V as input and with a pull up resistor will have 12V on the output? I found the SN7407 but it has 6 buffers inside the chip. I found many sinlge buffers but not with "High-Voltage Output". Thanks in advance.


SN7407 datasheet:
http://www.ti.com/lit/ds/symlink/sn7407.pdf (http://www.ti.com/lit/ds/symlink/sn7407.pdf)

Title: Re: Single Non Inverting Buffer With Open-Collector High-Voltage Output
Post by: Wimberleytech on May 17, 2018, 02:16:12 am

Are you constrained by space? 

Title: Re: Single Non Inverting Buffer With Open-Collector High-Voltage Output
Post by: 2X on May 17, 2018, 11:23:49 am

Yes, space is an issue.

Title: Re: Single Non Inverting Buffer With Open-Collector High-Voltage Output
Post by: Peabody on May 17, 2018, 02:04:35 pm

I'm not aware of of a single-gate part that will handle 12V on the output.  If you don't find one, you could combine a single inverting buffer such as the MC74VHC1GT04 with an NPN transistor.  You would need a base resistor and the collector resistor to 12V. 

Title: Re: Single Non Inverting Buffer With Open-Collector High-Voltage Output
Post by: David Hess on May 17, 2018, 07:04:37 pm

Do you need current gain?

If not, then a single NPN transistor operating in common-base mode with the base biased from the logic supply can operate as a high voltage buffer with an open collector output.  A single part like a pre-biased transistor (https://www.mouser.com/Semiconductors/Discrete-Semiconductors/Transistors/Bipolar-Transistors-Pre-Biased/_/N-ax1s9Z1yzvvqx?P=1z0y4diZ1z0xn16&Ns=Pricing%7c0) can work this way.  Any logic level n-channel MOSFET will also work.

Title: Re: Single Non Inverting Buffer With Open-Collector High-Voltage Output
Post by: T3sl4co1l on May 17, 2018, 10:10:17 pm

Yes, a dual BJT or MOSFET, with pull-up resistor [and base limiting resistor -- or use the "prebiased" kind]. ;D

Alas, sad that 7406/7 is the only 30V part (and there were some oddballs for driving nixie tubes at 100V+), IIRC.  When they made 74HC, they didn't try to make a 30V version.  Nor the 74HC1Gxx and TinyLogic families.  (Incidentally, 74LVC (and the respective TL family) is "high voltage tolerant", but that means 5V for a chip intended for 2-3V operation, not 30V. :P )

Tim

Title: Re: Single Non Inverting Buffer With Open-Collector High-Voltage Output
Post by: Wimberleytech on May 17, 2018, 11:13:48 pm

For dual MOSFET, here is an option: TD9944

Title: Re: Single Non Inverting Buffer With Open-Collector High-Voltage Output
Post by: 2X on May 18, 2018, 12:27:52 pm

Thanks all of you for the replies.