DRV595: The spur in input and faultz pin

Lacey Lin

Part Number: DRV595

Hi team,

When my customer use the DRV595 and they find some spurs related to the oscillator spur.

Below is the schematic

issue 1: They use the 4.7k resistor to pull up the FAULZ pin to 3.3V, but the voltage keep as 1.3V when they power up the device. Can you help to review the schematic and find the possible cause?

issue2: When they increase the voltage of the between the VIN+ and VIN-, they find some spur that in VIN+ and VIN- , and also FAULTZ pin.

Keep the VIN+ as 3V and decrease the VIN- to 2V,

There show some spurs in IN+ and IN- and the FAULTZ. The spur of FAULTZ also cause the FAULTZ switch to low voltage.
The spur frequency is 500kHz which is the same frequency of the oscillator frequency setting by the FS0-2.
When the voltage between IN+ and IN- increase, the level of the spur increase.

Please help to analyze the finding and find the possible cause.

Lacey

Thanks a lot!

over 5 years ago

0 Xiaolin Qin over 5 years ago

TI__Expert 6295 points

hello, can you please follow DRV595 user guide schematic to update your customer schematic?www.ti.com/.../slau479.pdf
1. Faultz is proposed to pull up to PVDD, not DVDD domain
2. Can you please also share host Analog output to DRV595 IN+/IN- schematic?

regards
Linda

0 Lacey Lin over 5 years ago in reply to Xiaolin Qin

TI__Intellectual 2900 points

Hi Linda,

Thanks so much for your reply!

Does the PVDD and DVDD you mean is the PVDD and AVCC?

The Faultz is OD type output, you mean it can't be connect to other power supply?

For the IN+/IN- schematic, will ask customer to provide.

Lacey

Thanks a lot!

0 Alix Wan over 5 years ago in reply to Lacey Lin

TI__Genius 9995 points

Hi Lacey,

As we have already discussed this issue offline, I would close this post.

Regards,
Alix Wan.

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DRV595: The spur in input and faultz pin