Data sheet acquired from Harris Semiconductor. SCHSD. CAUTION: The CDB, CDB, and CDB analog multiplexers are digitally-controlled . Product data sheet. Rev. 12 — 25 March 4 of Nexperia. HEFB. 8- channel analog multiplexer/demultiplexer. Fig 5. Logic diagram. An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in . Product Folder Links: CDB CDB CDB.
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Still, I was hoping for a method that wouldn’t tamper with the input signal in any way: Email Required, but never shown.
I’ve experimented with various delay times, and 30ms seemed to improve things a lot when reading sequantially 0, 1, 2, But the documentation on their website is generally incredibly poor, so I wouldn’t be surprised.
At the very least, connect a pullup resistor of about 10K between IN and the 5V power source. But this happens even with 1k resistor on Input 4.
If I read only port 4 for 30 seconds, it starts to read correctly and stable.
That is what seems to be the source of your problems. A 10K resistor works well in most cases. But it changes nothing. Sign up using Facebook. I saw a comment on the ‘arduino’ board which said that “the for loop repeatedly cycles count from 0 to 7, so [selector pins] will average 2.
I’d try using a different board. What is the signal source that you’re reading? LawrenceNK1G, I’m going to read a lot of things, like pots, voltage dividers etc. I’m a bit lost to what the dataheet could be.
You show that you’ve got your “Signal” leads connected to the select inputs. I’ve connected the input to 5V for testing stability of the reading. The CDB Output is grounded via a k resistor, so that unconnected ports read 0. Datasheet simulate this circuit — Schematic created using CircuitLab I’ve connected the input to 5V for testing stability of the reading. I’m using digitalWrite on three pins to select the input port, and then waiting delay for 30ms before doing an analogRead on A0.
Is it possible that they are getting triggered? However, the control inputs require CMOS digital levels.
(PDF) CD4051B Datasheet download
Though this may not be very relevant in this case, its important to note that the B is a CMOS device and hence anything less than 1. Sign up or log in Sign up using Google. I’ve tried removing the pull-down resistor. Is there a better alternative?
CDB from Texas Instruments
I imagine it could be something with capacitance on the ports, but I have the impression that the multiplexer is actually supposed to support very fast switching? Look at page 4 of this guide.
The value then starts reading randomly. It still goes to zero.
Ideally something that would allow multiplexing without distorting the signal. The IC has internal protection circuits. The Arduino has about 10Mohm resistance on the input side, so it shouldn’t make a difference, but the max reading was about instead of I’m using a breadboard of questionable quality.
CDB Datasheet(PDF) – TI store
Problematic breadboards cause loose connections within the board which you cannot see and hence lead to situations such as open connections etc. This means that this chip will not cd4051v with 3. I’ve also tried adding a 1uF capacitor. Also the pulldown resistor need not be that high. Home Questions Tags Users Unanswered. I’ve tried changing the pull-down resistor.