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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What is the signal source that you’re reading?
CDB Datasheet Harris Semiconductor pdf data sheet FREE from
If I read only port 4 for 30 seconds, it starts to read correctly and stable. Your drawing does not correspond with the nomenclature of the chip. I haven’t seen the block diagram for the chip but it seems that you may be shorting something internally inside the chip which is why the input drops to 0V after a short time.
Still, I was hoping for a method that wouldn’t tamper with the input signal in any way: Look at page 4 of this guide.
Home Questions Tags Users Unanswered. Problematic breadboards cause loose connections within the board which you cannot see and hence lead to situations such as open connections etc. Is it possible that they are getting triggered? I’d try using a different board.
You show that you’ve got your “Signal” leads connected to the select inputs. But perhaps I can calibrate it. I did try to add a 10k resistor in series with the input, but it changed the output. That is what seems to be the source of your problems. It still goes to zero. So – tell more about what is connected on the analog mux pins?
Email Required, but never shown. Sign up using Email and Password. I’ve programmed a small routine that checks for consistency of the signal reading. LawrenceNK1G, I’m going to read a lot of things, like pots, voltage dividers etc.
The IC has internal protection circuits.
But the documentation on their website is generally incredibly poor, so I wouldn’t be surprised. However, the control inputs require CMOS digital levels. The is an analog multiplexer – it can switch analog signals between Vee I’ve experimented with various delay times, and 30ms seemed to improve things a lot when reading sequantially 0, 1, 2, I’ve tried removing the pull-down resistor.
Is there a better alternative? I’ve tried changing the pull-down resistor. But it changes nothing. Wouldn’t the digital pins be able to sink fast enough that the IC would mux correctly? I’m using digitalWrite on three pins to select the input port, and then waiting delay for 30ms before doing an analogRead on A0.
(PDF) CD4051B Datasheet download
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 Sign up using Facebook. Ideally something that would allow multiplexing without distorting the signal. Though this may datasheeet be very relevant in this case, its important to note that the B is a CMOS device and hence anything less than 1.
Also the pulldown resistor need not be that high. I’m trying to multiplex an analog input port on an Arduino Uno.
At the very least, connect a pullup resistor of about 10K between IN and the 5V power source. I imagine it could be something with capacitance on the ports, but I have the datsheet that the multiplexer is actually supposed to support very fast switching?
The value then starts reading randomly.
But this happens even with 1k resistor on Input 4. I’ve connected the input to 5V for testing stability of the reading.
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Datasheet simulate this circuit — Schematic created using CircuitLab I’ve connected the input to 5V for testing stability of the reading. From the Arduino wiki page, it reads “Futhermore, the is able to work with analog values; in the case of the Datashret, you are able to use the analog inputs with a voltage between V and route them to an Analog-In Pin on your Arduino.
The CDB Output is cd405b via a k resistor, so that unconnected ports read 0. A 10K resistor works well in most cases.
If I start reading random ports between 0 and 7it reads correctly for about 10 seconds, then suddenly starts reading zero. Sign up or log in Sign up using Google. This means that this chip will not work with 3.
I’m a catasheet lost to what the problem could be.