Other Parts Discussed in Thread: SN74ABT16841
Hello,
Im having some trouble finding a replacement part for a D-latch SN74LS273. In short summary, we are upgrading some of our older machines that previously used SN74LS273 for controlling some solid-state relays. The old machines have control circuits that operates with 5V, however we would like to upgrade these machine and replace the processor with a Microcontroller that will operate with 3.3V, while keeping the 5V controlled solid state relays. For cost purposes, we want to keep the current relays and not replace them (we have about 50 output relays in total).
I have looked at multiple D-latches and found that usually with VCC at 3.3V, the MAX voltage range applied to the output is also at VCC (+/- some tolerance). Because my outputs would be connected to 5V with a pull-up resistor, i don't believe this would work powering the D-latch with 3.3V. I was hoping that there's a certain type of D-latch that can be powered with 3.3V and control a 5V output (drawing 2-10mA, sinking current).
I'm trying to keep this design minimal regarding number of chips. there are a total of about 50 output relays to control, so if i used 8-bit D-latches i would need about seven [7] D-latches. I understand that i can possibly use a voltage translator in between the microcontroller and D-Latch, but that would also require another seven [7] voltage translators. I was hoping i could just use one chip for the interfacing instead of two. maybe there's another type of chip i'm unfamiliar with that would be better. In the past we have used 74AC05 for a replacement for similar situations, however we need a LATCHING Chip for this to work properly as we will have multiple chips sharing the same 8-bit control bus that we will need to select separately. I drew a sketch below. Any recommendations or insights are appreciated.
