Tri-state buffer with Low-V[IH]?

We've had that problem ourselves, namely wanting to run a 5-volt powered TinyLogic part from a 3.3 volt FPGA. It actually works, but they get hot if the input parks at 3.3 volts.

Adding one diode drop of positive offset helps a lot, but is messy.

An LVDS-to-TTL receiver isn't a bad way to go, except for your tristate thing. I wish some of the Tiny parts were "HCT" types.

John

We routinely use the 74AHCT2G125DP part from NXP for the specific purpose of converting 3.3V logic signals to 5V swing at the output. These parts are two drivers per package in a small TSSOP8 package with a body size that is a nominal 3x3mm in size. The V[IH] is specified at 2.0V Min when the VCC is operated from 4.5 -> 5.5V.

Typical usage on motherboards is to re-drive the HSYNC and VSYNC signals from video controller to have 5V swing at VGA connector.

--
- mkaras

How it's done properly, as I did on the my USB designs for Intel:

A hack, but it works:

There should be some 3.3V-to-5V translators out there that you can buy. ...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
      The only thing bipartisan in this country is hypocrisy

fairchild has and,or,nand,nor,xor,inv HST type tinylogic parts

-Lasse

The real deal, pretty much exactly as you want...

...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
      The only thing bipartisan in this country is hypocrisy

That looks like it's exactly what I need, and it's a drop in replacement for the 7wz125 that is causing me problems. Thanks very much.

Mike.

Too bad nobody stocks 'em.

--
 Thanks,
    - Win

74HCT2G125DP and 74HCT2G126DP, they're in stock. 74AHCT2G126DP is in stock... Various AHCT gates. AHCT is considerably faster than HCT.

--
 Thanks,
    - Win

I've got 50 of them in front of me already thanks to Mouser. But you're right, they are normally not stocked.

Mike