replacement for hef4050 (driver) cd4096ube (inverter) due 3.3v instead 5v

Roelf Brouwer

Prodigy 30 points

Other Parts Discussed in Thread: TXB0108

For driving 4 datalines (2 as output and 2 as input) ihave have this buffered.

1 input and 1 output is normal, 1 input and 1 output is inverted.

works well with 5v ofcourse. But the voltage in the project is

changed to 3.3v. Wich ic I can use as replacement?

I can use inline a level shifter like TXB0108 but I want to

avoid that. I thought about the 74LVC06 and 74LVC07.

They need to drive the TIL 111 optocoupler. This is

because the data input is 15v TTL.

I prefer DIL-casing. Is this Availble?

over 12 years ago

0 Chris Cockrill over 12 years ago

TI__Mastermind 46480 points

Do you need to translate 3.3V to 5V? does it need to be pin compatible with 4050?

0 Roelf Brouwer over 12 years ago in reply to Chris Cockrill

Prodigy 30 points

Yes, the normal i/o voltage of the IC that was drive the 4050 was 5V. By changing this

IC I noticed it had a 3.3V I/O voltage. It's a bit tricky but 3.3V low level ttl will work on

a cmos but I had too much problems (read as lost data or jitter). I think this is because

the CMOS family has another Voh, Vih and Vit.. After studying it seems I can replace

the driver and inverter ic's for a TTL 5V. Maybe now my question is changed for

easier understanding. When I have an IC working on 3.3V TTL (5V tolerant inputs)

can I use inline of this IC a normal 5V TTL? Another question about the package,

wich series number I need for the fastest IC in DIL-casing?

0 Chris Cockrill over 12 years ago in reply to Roelf Brouwer

TI__Mastermind 46480 points

Hi Roelf

The answer is yes. You can use a 3.3V Cmos part with 5V TTL inputs. CMOS parts have a threshold at 50% Vcc TTL parts have a thrshold of about 1.5V . A 3.3V Cmos part will have about the same thrshold as a ttl part so we consider a 3.3V Cmos part TTL compatible.

Our fastest 3.3V Cmos family is LVC.

0 Chris Cockrill over 12 years ago in reply to Chris Cockrill

TI__Mastermind 46480 points

SN74LVC04 is pin compatible with 4069

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replacement for hef4050 (driver) cd4096ube (inverter) due 3.3v instead 5v