Real world differences between CD4049 and 4069?

[Rob Strand]

The 4049 was I read, originally a bespoke design for a customer. Each inverter had to drive a large number of TTL inputs from high level logic. So it has a strong pull-down output and the gate inputs can go higher than the chip Vdd (so no diode to Vdd).

That story makes a lot of sense.    In essence it could be used as a level translator from CMOS *to* TTL.

I wonder if anyone has to tried adding pull-up resistors to the BBD clocks from the 4049? This would help the weak current source of the CMOS while giving the much stronger current sink a little more work to do.

I haven't seen it for BBD's but it's a common trick to nudge the drive capabilities.



EDIT:  Well there you go.  TI datasheet.   In the opening blurb, level translation:
https://www.ti.com/lit/ds/symlink/cd4049ub.pdf

[POTL]

I haven't seen it for BBD's but it's a common trick to nudge the drive capabilities.

MXR micro flanger use 4069 + mn3204.