433MHZ wireless receiver become HOT.

[fuzzzy]

HI,

I'm making a unidirectional communication between 2 PICS. I'm using a 433MHZ FSK modulator at 9600baud. during work also when i'm not trasmitting anything it become very very hot. It has a 5V power supply as in datasheet. it's too hot. i've to close it in a box and it is dangerous it could damage. whata do you suggest me to do??

datasheet says it absorbes 5mA only.

Thanks

 

[polymath]

What suppy voltage have you got on 433 TX module?

Some transmitters require only 2v1<-->4v0
but their receiver will accept 5v0

If the supply voltage is too high you will turn on the substrate diodes
and it will get very hot very quickly.

Check data sheets from different source,
Check supply voltage AND supply current.
How clean is your supply?
Is the TX modulating any supply regulator you are using?

Try running at lower voltages and look for a step change in supply current.

hope this helps Polymath

 

[fuzzzy]

datasheet says 4,5V min 5,5 max power supply. so i don't want to use lower voltage for power supply. I hope this is a normal behaviour!

 

[polymath]

I am somewhat confused

You say it runs VERY VERY HOT - IT'S TOO HOT - IT IS DANGEROUS

yet you do not wish to diagnose the fault by some basic testing

you can lead a horse to water .....................

Polymath

 

[lambtron]

1. Check vcc. Verify with dvm that it is 5V and double-check the datasheet to make sure vcc and ground are applied to the correct pins.

2. Verify with ohm-meter that pic, modulator and oscillator all share a common ground.

3. Make sure all digital inputs are either driven at all times or pulled up (or down). In particular, if the modulator has a bidirectional pin that is connected to the pic, make sure it never floats; it may need a pullup resistor if there are times when neither the pic nor modulator are driving that net.

4. Verify the clock into the modulator with an oscilloscope. Look for proper amplitude and frequency, and verify that the voltage never goes below ground or above vcc.

 

[fuzzzy]

I verifyed digital output pins with tester. it'a always modulating as the receiver receives data also when transmitter is off.instead when i drive up or down input pin of transmitter, output pin of receiver goes to zero. This could be the problem.