Sleep Current Changed without no reason

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hqf2013
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Sleep Current Changed without no reason

Hi Dialog,

We developed a device with a DA14585, an external flash and a CR2025. After downloading our firmware, we measured the current consumption in sleep mode is about 4uA. But after serval days' testing, the current consumption became about 560uA in sleep mode. We checked all the components,and found that this phenomenon is caused by DA14585. we replace a new DA14585 on our board. The current consumption in sleep mode became about 4uA again. what happened? 6 of 30 devices met the same problem. Could you give me some advices? 

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PM_Dialog
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Hi hqf2013,

Hi hqf2013,

Probably some of the devices are not going into sleep mode and then go into WFI. When the system is in IDLE state the current consumption is around 560uA. Since you have a custom board, can you please share more inputs on that? Can you please check if the 6 boards are fully operational? Are you using any of our SDK examples?

Thanks, PM_Dialog

hqf2013
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Hi PM_Dialog,

Hi PM_Dialog,

 

Thanks for your reply. 6 boards are fully operational, except the current consumption. We double checked the IO  resistance to GND. We found the resistance of one PWM output IO to GND became about 200Ω. I think this is the reason for high current consumption. We use the PWM output IO to drive piezoceramic buzzer directly. Is there any problem for me to drive the buzzer?

 

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PM_Dialog
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Hi hqf2013,

Hi hqf2013,

I don’t see any issue with the usage of the buzzer. Let me ask you something. Can you please clarify if you are using the same or the different PCD? Can you also probe the GPIO which is the buzzer connected? Assume, that you are running the same firmware.

Thanks, PM_Dialog

hqf2013
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Hi PM_Dialog,

Hi PM_Dialog,

We use a buzzer 20mm in diameter. I'm a little confused to PCD. The 30 devices are running same firmware and using components from the some batch. We probed the GPIO this morning using a oscilloscope. The PWM IO voltages of devices which work properly are around 3.38V. The voltages of devices with high sleep current are 3.1v or 2.0v.   

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PM_Dialog
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Hi hqf2013,

Hi hqf2013,

Since you are using an external SPI Flash, can you please try to power it down and measure the power consumption? Also, please make sure that you are measuring only the DA14585 consumption and your board doesn’t have any leakages.

Regards, PM_Dialog

hqf2013
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Hi,PM_Dialog,

Hi,PM_Dialog,

What we found was that the our boards worked well at first with 4uA in sleep mode, then some of them met high power consumption problem, and then we replaced the DA14585 component and all of them were fine again. We think there's something that causes the IO to be broken down.  We don't know what type of output is. Open-drain or Push–pull?

Thanks,

Qinfei

PM_Dialog
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Hi hqf2013,

Hi hqf2013,

Can you please clarify your last question? Are you asking about the default state of the GPIOs?

Thanks, PM_Dialog

hqf2013
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Hi, PM_Dialog,

Hi, PM_Dialog,

1. We want to know under what circumstances the IO pins will be broken down.

2. We found that "in output mode and analog mode the pull-up/down resistors are automatically disabled" from the datasheet. What is the driving capability of the output pins?

 

Thanks,

Qinfei

 

PM_Dialog
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Hi hqf2013,

Hi hqf2013,

Please refer to DA144585 datasheet in order to find the maximum (Table1) and the recommend (Table2) rating for the pins.

Thanks, PM_Dialog

hqf2013
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Hi, PM_Dialog,

Hi, PM_Dialog,

We reviewed the datasheet 3v3 repeatedly. Table 2: Absolute Maximum Ratings, Table 3: Recommended Operating Conditions, Table 11: Digital Input/Output - DC Characteristics, all of them only mention the voltage problem, and there is no mention of how much the output current can be as large. We wonder if it will be a particularly large current that has broken down the output pins.

 

Thanks,

Qinfei 

JE_Dialog
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Hi All, this is most likely

Hi All, this is most likely due to battery bounce and the device is not starting-up properly. It is a known phenomenon and there is a simple fix.. The best way to sovle this is to use a 1uF capacitor from RST to Vcc.

See AN-B-054 for the DA14585 section 5.7.

This is fixed on our new device that launches very soon.

BR JE_Dialog