From: "Roger Hamlett"
Subject: Re: Searching for alternative to ULN2003 (need inverting logic)
X-Newsreader: Microsoft Outlook Express 5.50.4807.1700
X-Inktomi-Trace: pc3-bsfd1-5-cust109.cmbg.cable.ntl.com 1039546587 15880 18.104.22.168 (10 Dec 2002 18:56:27 GMT)
Date: Tue, 10 Dec 2002 18:56:08 -0000
NNTP-Posting-Date: Tue, 10 Dec 2002 18:56:28 GMT
Organization: ntl News Service
"Joe Blo" wrote in message
> I am currently using a ULN2003
> to drive P-channel MOSFETS. This design is for a low speed
> application, so I am not concerned with switching speed.
> I need to find a similar device that has an inverted logic, as in a
> low-signal turns on a low side driver in the ULN2003 to drive the
> connected P-channel FET. I need a chip that has a similar # of drivers
> in a package (7) and is similar in cost. Thanks
Do you mean this?.
I'd have thought if you are using the ULN2003, to turn on P-Channel FET's,
the 'inverse' device would be wanting to turn on N-Channel FET's?. In this
case, you'd need a high side driver, rather than a low side driver. , In
general, be careful of the 'turn off' times, with a ULN type driver, since
if this is slow, you may suffer from a moment, when both drivers are are on
at the same time....
If you do need a 'non inverting' high side driver, similar to the ULN, try
looking at the UDN2981, which is a fairly similar non inverting driver (8
per package rather than 7), with 'pull up' outputs, rather than the ULN's
'pull down' drives.