# Analog Multiplexer

#### Mojtaba67

Joined Jan 19, 2023
3
Hello every one,
I am very beginner.
At the moment, I am using an 8 channel relay with power consumption of (5 volt) × (70 mA) = 350 mW.
It is intended to find an analog mux with power consumption as low as possible.
Could you please introduce me an analog multiplexer with 8 channels.
The sampling rate of the analog signal is 10 MHz.
Mojtaba

#### ericgibbs

Joined Jan 29, 2010
19,082
Hi M67,
Welcome to AAC.
As a staring point, is this type suitable for your project.?
E

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#### Mojtaba67

Joined Jan 19, 2023
3
Hi @ericgibbs

I see that the power consumption is very low which is a good point.

I tried to find its bandwidth in the datasheet, but I couldn't. The frequency (or sampling rate) of my signal is at most 10 MHz.

Do you think this IC can support this frequency?

Moreover, if you introduce me to a circuit board containing this IC, it would be much easier for me to connect it to the other devices.

Thank you

#### ericgibbs

Joined Jan 29, 2010
19,082
hi M,
You say your present system uses relays. Which have relatively low switching speeds of say 10 to 20mSec.
If your intention is to replace the relays with Analogue multiplexers, why do you need the high speed of 10MHz.?

Is it the ADC which is running at 10MHz.?

E

#### Ian0

Joined Aug 7, 2020
10,249
I’d suggest DG408 etc as well. The capacitance between adjacent pcb tracks might be your first problem, and the capacitance of the switch when it is off. Its performance may depend on the source impedance of your signal.
Specifications are quoted at 1MHz, so presumably it must work at that frequency.

#### Mojtaba67

Joined Jan 19, 2023
3
Hi @ericgibbs
I try to explain with a figure.
I have a wave generator that generates a sine wave with a frequency of 10 MHz. The duration of this wave is 2 seconds.
I want to apply this wave to Device 1.
after 1 hour (I mean a big time interval), I want to apply this sine wave to Device 2.
Then Device 3, and so on...
For this application, I am looking for a mux.
One person told me a mux should have the capability to pass through itself at such a frequency (10 MHz).

#### ericgibbs

Joined Jan 29, 2010
19,082
hi M,
I see on the datasheet it refers to Transition times in the order of 20nSec for tf and tf

I would suggest you contact Intersil, the device manufacturer, to confirm your 10MHz requirement.

E
For reference this a 2nd image shows the idealised possible effect of these rise times may have on the original signal

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#### ronsimpson

Joined Oct 7, 2019
3,203
There will be some signal on the off channels. The data sheet thinks as much as 1% of the signal at 10mhz.
The on resistance is about 90 ohms. The internal capacitance is 90 to 180pF. That will reduce you output some. I am surprised there is not a graph for that.