Sounds like you need 1 latch/FF and 12 or 16 2:1 mux functions. Having the latch or not doesn't matter much in this case.Could someone show me an example of an off-the-shelf part and recommend one for my project? I need to multiplex two 12-bit (or 16-bit) data inputs.
Semiconductor manufacturers, e.g. TI, have search machines for their logic ICs. It's the straightforward way to find out which logic functions are available.
Sounds like you need 1 latch/FF and 12 or 16 2:1 mux functions. Having the latch or not doesn't matter much in this case.
I guess "registered" is the correct term. I'm trying to keep the component count down for a simpler PCB, even if these muxes will cost more. I'm new to PCB design so I just want as few chips as possible, with as few traces to route as possible.My fault, I understood latching the select signal.
I don't know any registered 2:1 muxes.
That actually looks kind of like what I need. It says "1000MHz" minimum operating frequency... My circuit will be variable frequency switching between 14, 28 and 56MHz.I don't really understand what you want but https://www.onsemi.com/PowerSolutions/product.do?id=MC10E167FNR2G
MC10xx is a PECL GHz logic series and surely not suitable for your application.
The next best fit in CMOS logic are "registered multiplexed bus exchangers" like SN74ALVCH162268.
Transparent latches in the B-to-A path allow
asynchronous operation to maximize memory access
throughput. These latches transfer data when the
latch-enable (LE) inputs are low.
Hi,
Latch enable:
The datasheet gives the answer:
See bottom truth table on page 2.
Klaus
What does this mean?Output level before the indicated steady-state input conditions were
established
What does this statement mean?Output level before the indicated steady-state input conditions were
established
What's a transparent latch? Or rather, what makes a latch "transparent"?
https://en.wikipedia.org/wiki/Flip-flop_(electronics)Flip-flops can be either simple (transparent or opaque) or clocked (synchronous or edge-triggered). Although the term flip-flop has historically referred generically to both simple and clocked circuits, in modern usage it is common to reserve the term flip-flop exclusively for discussing clocked circuits; the simple ones are commonly called latches.
Using this terminology, a latch is level-sensitive, whereas a flip-flop is edge-sensitive. That is, when a latch is enabled it becomes transparent, while a flip flop's output only changes on a single type (positive going or negative going) of clock edge.
a latch is level-sensitive, whereas a flip-flop is edge-sensitive
I'm thinking since I transmit video DAC data I have a steady zero output during video blanking,
Hi,
Just to be sure:
Are you talking about the analog DAC output
Or the digital DAC input?
Our answers are only valid for digital ligic signals. No analog signals.
***
For "freezing" analog signals you need a "sample-and-hold" circuit.
Klaus
Hi,
OK,
But doesn´t have the DAC a latch or a FF built inside?
I think usually they have...
Could you post a draft of your (expected) circuit?
Klaus
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