DRV10987: DRV10987 motor start up fail randomly

Hollis Liu

Part Number: DRV10987
Other Parts Discussed in Thread: DRV10974

Tool/software:

Hi team,

my customer is using DRV10987 for motor driver. The SCH is as below,

but customer finds the motor can not start up successfully randomly. The ratio is about 20%. they tried to switch the motor drive IC. The issue follows IC.

below is the test wave on PIN 9(yellow) and PIN 2 during start up failure.

any suggestions for debug? Thanks.

5 months ago

0 Hollis Liu 5 months ago

TI__Intellectual 2595 points

add SCH

0 Hollis Liu 5 months ago in reply to Hollis Liu

TI__Intellectual 2595 points

Hi team,

looking forward to your suggestions. Thanks.

0 Venkatadri Shantaram84961 5 months ago in reply to Hollis Liu

TI__Mastermind 23202 points

Hi Hollis,

Sorry this thread was missed, let me verify the issue.

The schematic you shared is DRV10974 but the problem is mentioned for DRV10987, can you please confirm?

Also, can you provide EE and customer name?

Thanks and Best Regards

Venkatadri S

0 Hollis Liu 5 months ago in reply to Venkatadri Shantaram84961

TI__Intellectual 2595 points

Venkatadri,

sorry, my fault. it should be DRV10974.

0 Venkatadri Shantaram84961 5 months ago in reply to Hollis Liu

TI__Mastermind 23202 points

Hi Hollis,

I looked at schematics, few small corrections

1. PWM pin as internal pull up, do they need external pull down? What is the speed command mode analog or PWM?

2. CS pin has 15k, it is less than recommended 16.2k-> Try to use the values from the table mentioned in the data sheet and EVM user guide.

3. AVD is 50us with 18k, check if this is suitable for the motor, follow the instruction as per user guide.

4. C740 used on V1P8 is 2.2uF, can you use recommended value of 1uF?

You mentioned defect following the device, does that mean ABA swap is working on the PCB?

Thanks and Best Regards

Venkatadri S

0 Hollis Liu 5 months ago in reply to Venkatadri Shantaram84961

TI__Intellectual 2595 points

Hi Venkatadri,

yes, ABA swap is done. Defect follows the devices.

0 Venkatadri Shantaram84961 5 months ago in reply to Hollis Liu

TI__Mastermind 23202 points

Hi Hollis,

Do they have facility to measure the pin resistance for the device? Measure for all the pin and compare with correlation unit?

With ABA swap if the defect following the device, we should be able to observe if any drift , please help to monitor VCP, FR pin, V1P8 in levels and compare with good unit.

Also, measure the open loop time from start up to handoff point between working and defective part? This is to check if any parametric drift (clock)

Let me know if you need explanation and we can get on to webex call.

Thanks and Best Regards

Venkatadri S

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DRV10987: DRV10987 motor start up fail randomly