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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I’m a bit lost to what the problem could be. The is an analog multiplexer – it can switch analog signals between Vee At the very dattasheet, connect a pullup resistor of about 10K between IN and the 5V power source. I’ve tried changing the pull-down resistor.
I’ve connected the input to 5V for testing stability of the reading.
(PDF) CD4051B Datasheet download
Problematic breadboards cause loose connections within the board which you cannot see and hence lead to situations such as open connections etc. Post as a guest Name. Email Required, but never shown. A 10K resistor works well in most cases. 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?
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 Home Questions Tags Users Unanswered.
CDB from Texas Instruments
I’ve tried removing datasheeet pull-down resistor. But the documentation on their website is generally incredibly poor, so I wouldn’t be surprised.
Still, I was hoping for a method that wouldn’t tamper with the input signal in any way: Ideally something that would allow multiplexing without distorting the signal. That is what seems to be the source of your problems. Look at page 4 of this guide.
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Your drawing does not correspond with the nomenclature of the chip. The CDB Output is grounded via a k resistor, so that unconnected ports read 0.
I’ve programmed a small routine that checks for consistency of the signal reading. From the Arduino wiki page, it reads “Futhermore, the is able to work with analog values; in the case of the Arduino, you are able to use the analog inputs with a voltage between V and route them to an Analog-In Pin on your Arduino. But perhaps I can calibrate it. So – tell more about what is connected on the analog mux pins?
If I start reading random ports between 0 and 7it reads correctly for about 10 seconds, then suddenly starts reading zero. I did try to add a 10k resistor in series with the input, but it changed the output. I’ve experimented with various delay times, and 30ms seemed to improve things a lot when reading sequantially 0, 1, 2, But this happens even with 1k resistor on Input 4.
I’m trying to multiplex an analog input port on an Arduino Uno. Is there a better alternative?
(PDF) CDB Datasheet PDF Download – CMOS Analog Multiplexers / Demultiplexers
This means that this chip will not work with 3. 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. I’m using digitalWrite on three pins to select the input port, and then waiting delay for 30ms before doing an analogRead on A0.
I’m using a breadboard of questionable quality. LawrenceNK1G, I’m going to read a lot of things, like pots, voltage dividers etc. Wouldn’t the digital pins be able to sink fast enough that the IC would mux correctly? Sign up or log in Sign up using Google. Sign up using Facebook. What is the signal source that you’re reading? However, the control inputs require CMOS digital levels.
The IC has internal protection circuits. Datasheet simulate this circuit — Schematic created using CircuitLab I’ve connected the input to 5V for testing stability of the reading.
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. Also the pulldown resistor need not be that high.
Is it possible that they are getting triggered? It still goes to zero.