TPS61291: ALTERNATE STEP-UP FOR CC1120

david ramos

Part Number: TPS61291
Other Parts Discussed in Thread: CC1120, , TIDA-01469, TIDA-00484

Hi to all,

I would like to know if there is any step-up recommended for working with CC1120 (small, low Emi,....) We are thinking to use the TI's TPS61291DRVR.

The idea is to make a sandwich of pcbs: one with the cc1120 transceiver and the second with the step-up and the main uC. Both pcbs will be connected in paralell

Could you recommend me literature for designing the lay-out? I've never mixed a DC/DC converter and a RF transceiver.

Thanks in advance

David

over 6 years ago

0 Jasper Li over 6 years ago

TI__Mastermind 46905 points

Hi David,
TPS61291 should be good. what is input voltage, output voltage and output current?

about the layout, please refer to the suggestion in the datasheet and also the EVM user's guide.

0 david ramos over 6 years ago in reply to Jasper Li

Prodigy 180 points

Hi Japer Li,

My input voltage is 3V. We are using a CR2 Lithium battery.

My desired output voltage is 3.3v.

Output current 200mA

My stack it is a four layer 0,8mm.

Is something really important the distance between the DC/DC and the transceiver?

here you have some notes. Firstly my sch, The other two pics the pcb routed.

the stack is included as well.

I think that I used all the recommendation I read on the data

Best Regards,

david

STACK_2076D.PDF

0 david ramos over 6 years ago in reply to Jasper Li

Prodigy 180 points

Hi Jasper Li,
After reading SLVA773-May 2016 .Please take into account the position of C2 and C3 on the pcb.
Could be this the rason of my headhache?
Best regards.
David

0 Jasper Li over 6 years ago in reply to david ramos

TI__Mastermind 46905 points

Hi David,
1. I think a bead should be add between the boost output and the transceiver.
2. about the boost layout, you can refer to the application note www.ti.com/.../slva790.pdf
3. the current PCB is not good. the connection between VOUT pin and the output capacitor should not go through vias

0 david ramos over 6 years ago in reply to Jasper Li

Prodigy 180 points

Dear Jasper Li,

After some days working, here is the last design of the pcb.

I used as reference:

TIDA-01469
ISE4035_TIDA-00484
TPS61291EVM

My question is about the bulk caps used on the mentioned designs. They have many and large capacitors but on my design I do not have a lot of space. I used two 0805 caps, one on top layer and the other on the bottom layer. Do you think I could have any problem because I use a bulk cap that it is not at the same layer that the DC Converter?

Many thanks for your help.

david