Communities

Writing
Writing
Codidact Meta
Codidact Meta
The Great Outdoors
The Great Outdoors
Photography & Video
Photography & Video
Scientific Speculation
Scientific Speculation
Cooking
Cooking
Electrical Engineering
Electrical Engineering
Judaism
Judaism
Languages & Linguistics
Languages & Linguistics
Software Development
Software Development
Mathematics
Mathematics
Christianity
Christianity
Code Golf
Code Golf
Music
Music
Physics
Physics
Linux Systems
Linux Systems
Power Users
Power Users
Tabletop RPGs
Tabletop RPGs
Community Proposals
Community Proposals
tag:snake search within a tag
answers:0 unanswered questions
user:xxxx search by author id
score:0.5 posts with 0.5+ score
"snake oil" exact phrase
votes:4 posts with 4+ votes
created:<1w created < 1 week ago
post_type:xxxx type of post
Search help
Notifications
Mark all as read See all your notifications »
Q&A

Controlling the shutdown pin of an IR Transceiver

+1
−0

I am using an IR transceiver in my design.This IC is working at 3.3V supply.This IC need not be on always so I decided to give a control to it's shut down pin (Pin no 5,Shutdown Input. Active low).A transistor switch is used for this purpose.When the switch is ON the transceiver will be active and when it is off the transceiver shutdown pin will be connected to 3.3V. My circuit is given below.The value of R1 is 10K.

The base control signal is coming from a Microcontroller.The uC is also working at 3.3V

May I know this circuit is fine or not.

Image_alt_text

History
Why does this post require attention from curators or moderators?
You might want to add some details to your flag.
Why should this post be closed?

0 comment threads

1 answer

+0
−0
When the switch is ON the transceiver will be active

No, it's the other way around.

First, you should be able to see the bar over SHDN in the datasheet. That means negative logic, where low is asserted.

Second, on page 5 of the datasheet the description for the SHDN pin is "Shutdown input. Active low". For the shutdown function to be active (the device shut down), the SHDN pin must be low.

Another way to think of it is that instead of a not-shutdown input, it's a enable input.

this circuit is fine or not

Since a microcontroller is driving the shutdown logic, the inversion mentioned above should be no issue. The firmware can produce either polarity. I'm not sure I'd say this circuit is "fine", but it should work.

However, what's the point? You have a 0 to 3.3 V logic signal you want to drive with a microcontroller that is also running on 0 to 3.3 V. The obvious answer is to connect an output of the micro directly to the shutdown input of the IC. If you care what happens at power up, put a 100 kΩ or so pulldown on the line. That way the IR IC stays off until the micro deliberately enables it.

History
Why does this post require attention from curators or moderators?
You might want to add some details to your flag.

0 comment threads

Sign up to answer this question »