Rob, I think he probably means the SN74LV595A, which works down to Vcc=2V. I suspect that you really want something that will interface directly with low voltage (3.3V or less) and has a higher voltage output (5V). I've been doing 3.3V and lower designs almost exclusively the past 5 years or so and haven't run across such a beast yet. If you want to "do it right" and not stretch any of the IC specs you'll have to go the level translator route. If your design is a one-off or hobbyist use then this is a pain. If it's a production design then it can be done fairly cost effectively and take very little PCB space. Here are a couple methods which I have commonly used. Note the 1st circuit is driving a TPIC6C595D (which is driving White LEDs in this case). ;-) The second circuit is interfacing to a 5V only PLC communications bus transceiver which has strict .85(Vcc) logic high levels. http://www.mps-design.com/misc-images/leveltrans1.gif http://www.mps-design.com/misc-images/leveltrans2.gif The first circuit is quite economical as it's only two packages and the 74LVC07 can be had in a VSOP package if PCB real estate is important. Total cost for production is probably about $.20 total. The circuit is speed limited though since it uses open drain type drivers and is not the most power friendly since it's switching a fairly stiff current through the pullup resistors. In this application it didn't matter as the pullup resistor current was << than the LED current. The second circuit is a bit more costly (probably about $.35 total) but still quite compact. Since all the drivers are active the speed performance is excellent and static power dissipation is very low. The SN74LVC2T45DCTR is bidirectional so that may be useful to you. TI also makes this part in single gate and I believe quad gate parts as well. The quad gate part could do all your required level shifting in one package, most likely. The SN74LVC2G34DBV is a low voltage part with 5.5V tolerant inputs, comes in a SOT23-6 package and is quite inexpensive. I'm quite sure they make a single gate package as well. Matt Pobursky Maximum Performance Systems On Sat, 26 Jan 2008 10:23:41 -0800, Rob Robson wrote: > Thanks, Bob. If it can drive small relays, it sounds exactly like what > I'm looking for. Unfortunately, I come up empty-handed when I search on > that (partial?) part number on the TI site or Digi-Key's. I can't find > it by doing a parametric search on TI's site either. Are you sure about > the part number? > > Best regards, > RR > > > ----- Original Message ----- > From: "Bob Axtell" > To: "Microcontroller discussion list - Public." Sent: > Saturday, January 26, 2008 4:32 AM Subject: Re: [EE]: 3.3V-friendly > TPIC6C595 > > >> Rob Robson wrote: >>> I'm looking for an equivalent to the venerable TPIC6C595 shift >>> register/driver that could be driven by a micro running from 3.3V >>> without having to add a level converter. Has anyone used or found >>> such an animal? >>> >>> TIA, >>> RR >>> >>> >> why not use the TLV595? It works at 3.3V admirably. Texas Instruments >> makes them. I would avoid >> Fairchild's version, too sensitive to noise for my blessing. >> >> The device also buffers the signal well enough to drive external loads >> easily... >> >> >> --Bob A >> -- >> http://www.piclist.com PIC/SX FAQ & list archive >> View/change your membership options at >> http://mailman.mit.edu/mailman/listinfo/piclist -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist