Yes Bug13, I agree. Those power traces are way too small. And the regs have next to no heatsinking.
Also, bypassing the CPU.

They need to be removed.
Does anything work when running on 5V? I wonder if the problem is on the 5V supply, the transmitter RF is interfering with the rest of the circuit.
And maybe it tried to draw more current and resets the processor as the reg shuts down briefly.
An oscilloscope on the supply may help to work it out.
But the reg is nor good enough for the job. Cut the 5V feeding the radio and add another higher power reg for it. Then you have a separate clean supply for the cpu and radio. I tend to use the switch mode regs for a lot of my boards.
http://au.element14.com/tracopower/tsrn-1-2450/dc-dc-converter-1a-5v-5w/dp/2280247
These are pretty expensive so look to Ebay.
Try one of these..
https://www.ebay.com.au/itm/Voltage...885311?hash=item1ed219317f:g:RfMAAOSwke9Z6quW

Thanks for the solution dendad. Let me try this LM2596 instead LM1117 since LM2596 has low switching frequency. i'll try that and let you know. meanwhile i need some knowledge on adding decoupling capacitors and ferrite beads.

how to choose the ferrite bead for this module and where the decoupling capacitors has to be added in the circuit. it could be helpful, if you guide me on this.

Thanks

 

Maybe add some decoupling caps too, I don’t see any for your atmega328p

Hi bug,

Thanks for your reply. I just need your guidance in adding the decoupling caps on board.

Thanks

 

Hi bug,

Thanks for your reply. I just need your guidance in adding the decoupling caps on board.

Thanks

For the MCU, just add some 100n caps for every pair of VCC and GND, as close to the chip as possible, generally within 2mm.

If you are using ADC, do this:
Page 313, Datasheet is your friend:
http://ww1.microchip.com/downloads/...-Microcontroller-ATmega328-328P_Datasheet.pdf

For the RF module, you need to actually confirm your power source (battery) can not supply enough current is the problem, before trying to fix it.

• Have you confirmed this is the cause of your problem yet?
• What battery are you using? Mainly what chemistry of your battery?

 

Hi,

This Thread may be weird but happening in my RF System.

Designed an RF Board which was about to supply 5v to an RF Transceiver Module via LM1117 5V o/p and the input to the regulator was given from battery (7.4V, 3.35Ah).

When an external power supply (5V,1A) is directly connected to the the input pins of the board , The transceiver module is working properly and if i connect the battery to the input pins, the transceiver module is not working which means it is neither transmitting nor receiving any data.

The Important factor is that either connecting the external power supply or battery supply, the power goes through the voltage regulator and reached the RF module.

but Why it is working only with external power supply and not with the battery?

Someone help me out to sort this issue.

Thanks in Advance!

Just going off of your original statement above, this is really simple.

An LM1117 (5VDC version) requires at least 6.2VDC input at 1A in order for it to be able to output 5VDC @ up to 800mA (max). The only way you can power your PCB with an external power-supply (PSU) at 5VDC @ 1A, is if you bypass (go around) the LM1117.

If you power the LM1117 via a 7.4VDC 3.xAh battery, the LM1117 still limits you to 800mA on the output.

This is why it's failing.

Powering directly with a 5VDC @ 1A PSU is giving your tranceiver enough juice. The battery isn't because the regulator only puts out 800mA, which apparently is not enough for your tranceiver.

Why don't you put an ammeter on the output of your PSU into your tranceiver and find out how much current it actually takes, and then choose an appropriate regulator (like an LM7805), which can deliver 1-1.5A.

 

The main things is that's your Rf module tuned at 5volt, if you change RF module power supply voltage, your RF module tuned to another frequency, RF Module is still working but it's frequency you don't find it. If you want to run RF Module to 7.4 volt, you tell it's frequency and working purpose. I will help you.

 

The main things is that's your Rf module tuned at 5volt, if you change RF module power supply voltage, your RF module tuned to another frequency, RF Module is still working but it's frequency you don't find it. If you want to run RF Module to 7.4 volt, you tell it's frequency and working purpose. I will help you.

The RF module frequency will not be affected by the voltage. It will be crystal locked. Otherwise if would be largely unusable.

 

which Power Amplifier you recommend for 100mW to 1W power Amplification for RF Modules?

I'm just designing a circuit with Max 2235. is it okay to go with that?

 

I think it may be illegal to boost the power of your modules. Check with local laws.

 

I think it may be illegal to boost the power of your modules. Check with local laws.

Hi,

Its not for the commercial purpose, i need to experiment it. So kindly let me know is it possible with MAX2235?

 

Its not for the commercial purpose, i need to experiment it. So kindly let me know is it possible with MAX2235?

The regs don't just apply to "commercial purposes". Unless you hold an apropriate license, it is illegal I would expect.

 

Hi,

Its not for the commercial purpose, i need to experiment it. So kindly let me know is it possible with MAX2235?

Just buy one with the output power you want, to get it right, you need a few expensive equipment. Unless you are a student and have access the equipment from your university.