SN74CBTLV3251: Input Digital Decoder Selection Problem

Viraj Dali

Hallo
I am performing the testing of multiplexer via microcontroller. I am providing the logic for address/select lines via Microcontroller GPIOs. But while testing I am facing the problem that my multiplexer is only giving output to 8(B8) pin as it is 1:8 MUX. In spite, I am changing the logic of address lines via microcontroller, the Multiplexer is only connecting its input to 8th output pin. The multiplexer I am using is from Texas Ins. SN74CBTLV3251.

Can somebody suggest what could be problem ??

Thanks in advance

over 9 years ago

0 Louie over 9 years ago

TI__Expert 3180 points

Hello Viraj,

Thank you for taking an interest in our SN74CBTLV3251.

A series of things could be causing this issue.

Could you please check if:

1) As you change the logic on on you micro controller, that logic is being seen at the correct pins?

2) there is nothing pulling the S0, S1, S2 pin up to VIH

3) there are no shorts between S0, S1, S2

If you could share your schematic with us, it will allow us to better debug this device.

Thank you,

Louie

0 Viraj Dali over 9 years ago in reply to Louie

Prodigy 20 points

Hallo Louie
Thanks. I worked.
I would like to have little more information .

what is the power dissipation of this IC(SN74CBTLV3251) ??

Thanks in advance

Viraj

0 Louie over 9 years ago in reply to Viraj Dali

TI__Expert 3180 points

Hello,

The power dissipation of this IC is dependent on a series of other factors.
The switch itself does not consume power, but rather the digital logic which control which switch turns on/off.
It will be the Icc that goes through that portion of our chip which dictates.
This Icc will change with what your switching frequency of the switch is.

Thank you,

Louie

0 Adam Torma over 9 years ago in reply to Louie

TI__Mastermind 45780 points

You may find this e2e post useful for an example on how to calculate the power dissipation for a signal switch.

How to calculate max junction temperature (Tj max) and max power consumption for an analog switch

Adam

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SN74CBTLV3251: Input Digital Decoder Selection Problem