CC1310: High Current Draw while in Standby

Steve Cook

Part Number: CC1310

I currently have a custom board that is using the same parts as from the LaunchXL-CC1310, with the addition of a temp sensor.
I tried running PinStandby Example and Notice a sleep current of 800uA, I run the same PinStandby example on the LaunchXL and see 10uA current draw.
I have taken off the Temp Chip and any additional components until all I had left was the exact schematic of the LauncXL Development board.

The only difference is that I have the 32 pin CC1310 and the LaunchXL has the 48 Pin version, is there a power function I am missing in the program that needs to be addressed with the pin difference?
I do notice that the DC/DC switch seems to be rather active during sleep, the oscilloscope showing no shutoff and recharge cycle like the LaunchXL does, but instead shows a constant high speed duty cycle of sorts.

Thanks!

over 4 years ago

0 Siri over 4 years ago

TI__Guru* 86131 points

First of all, I do not understand how you can measure 10 uA when running the pinStandby example? In standby the CC1310 is drawing less than 1 uA. Is it not the standby current you are measuring, but the average current?

Have you set all unused pin as PIN_UNASSIGNED?

Please see the following post:

https://e2e.ti.com/support/wireless-connectivity/sub-1-ghz/f/sub-1-ghz-forum/700735/cc1310-standby-power-consumption-on-custom-board

Siri

0 Steve Cook over 4 years ago in reply to Siri

Prodigy 135 points

Hey Siri,
I am programing the LaunchPad with the PinStandby example and then disconnected all Jumpers, powering the board using an external power supply. I'm using a calibrated Fluke Desktop Multimeter in line with the Ground power supply running to the board.
I get 8uA-12uA and that fluctuates a little.
I have ALL pins set to PIN_UNASSIGNED

I found the LP board 'issue' of 10uA to be the ExtFlash not being put to sleep. I commented that section out since my custom board does not have the external flash and that routine was causing debug to halt there. Un-Commenting this has brought the LP current down to 1uA as you said.

Do you suppose commenting this out could cause a current issue in my custom board as well?

thanks, siri.

0 Steve Cook over 4 years ago

Prodigy 135 points

Is there anyone who could even venture a possible cause as to why i'm seeing 800uA on a 32-pin CC1310 as opposed to 1uA on a 48-pin CC1310??
The circuits are almost identical, albeit different brands, I have swapped out Inductor and Capacitor components in the DCDC switch area of my custom board for the components on the Development board, but still see the 800uA draw.

I'm at a loss here.

0 Vegard H over 4 years ago in reply to Steve Cook

TI__Expert 4560 points

Hi Steve. Sorry for the late reply.

Can you share the design files?

0 Steve Cook over 4 years ago in reply to Vegard H

Prodigy 135 points

Hello Vegard,
I got a fun one for you here. I'm still waiting for one of those 'ah-ha!' moments.
Attached the very basic schematic here, it's a smart PDF so if you hover over a component (or maybe right click it) it will show the part number/manufacturer...etc
You may have to download it for that capability, not sure.

0 TER over 4 years ago in reply to Steve Cook

TI__Guru**** 317180 points

TI has some restrictions on using remote drives. Would you be able to upload the schematic directly in this post?

0 Steve Cook over 4 years ago in reply to TER

Prodigy 135 points

Sheet1.pdf

+1 TER over 4 years ago in reply to Steve Cook

TI__Guru**** 317180 points

The schematic look ok. It could look like the chip never go down in the lowest power state.

Could you also check with the empty example project to see if you get a different current consumption?

For debug: Could you set the chip to use the internal 32 kHz (LF) RCOSC instead of the external 32 k XOSC? If the current change then you have a issue with your 32 kHz xtal.

0 Steve Cook over 4 years ago in reply to TER

Prodigy 135 points

Hey TER,
Yup that fixed it >.<, heh. Using internal RCOSC brought current down to 0-2uA (some meter accuracy variance there).
Not sure what's up there, I used the correct loading caps for the part number. Will have to look into this hardware more.

Much appreciated, everyone.

0 Steve Cook over 4 years ago in reply to TER

Prodigy 135 points

TER, I confirmed my loading caps and crystal are correct and I have an additional question for this topic.
I have the RSM 32-Pin board and that has X32K_Q1 on Pin 5 and X32K_Q2 on Pin 6
Where as on all other versions of the CC1310 X32K_Q1 is on Pin 4 and X32K_Q2 on pin 5.

If I am using code for the 48-Pin Launchpad board on my 32-pin CC1310, does this code route or reference X32K_Q1 and X32K_Q2 incorrectly?

0 TER over 4 years ago in reply to Steve Cook

TI__Guru**** 317180 points

No, the xtal pins are hardwired so you don't have to change the code with regards to the 32 kHz xtal.

I didn't manage to read the part number for the xtal from the schematic, which Cload is it spec'ed for?

0 Steve Cook over 4 years ago in reply to TER

Prodigy 135 points

ah, alright.
My LF crystal part number is ECS-.327-7-16-C
I confirmed that is the actual part on the board by reverse lookup of the code on top of the actual component.
I can also take off the the loading capacitors (0201) and confirm those with my LC meter, though quite superfluous.

I put a counter probe to the Crystal of my custom board (I know, I could potentially brick it) and saw it was running with the same amplitude as the Launchpads LF crystal, ~65mV pk-pk.

0 TER over 4 years ago in reply to Steve Cook

TI__Guru**** 317180 points

This xtal requires 7 pF Cload. You have used 7 pF load caps which give 3.5 pF Cload + parasitics which would give a bit too low total Cload. See 6.3 in https://www.ti.com/lit/an/swra640e/swra640e.pdf.

0 Steve Cook over 4 years ago in reply to TER

Prodigy 135 points

....
I will replace with 14pF and report back.
Thank you TER.

0 TER over 4 years ago in reply to Steve Cook

TI__Guru**** 317180 points

Or a bit lower. Remember to take into 1 -2 pF as the parasitic value.

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CC1310: High Current Draw while in Standby