DRV5013: Schematic Review Request for DRV5013 and SN74LVC3G17

Conor

Part Number: DRV5013
Other Parts Discussed in Thread: SN74LVC3G17

Hi,

Q1.
I would like advice on what to look out for when connecting DRV5013 to SN74LVC3G17. We need you to check the external components.
<Conditions>
■ Operating temperature: 5~80°C
■ VCC: 5V±10%

Q2.
C1 = 0.01uF connected to the DRV5013, but the datasheet indicates that C1 is 0.1uF or more. Which is correct in the data sheet?

Thanks,

Conor

10 months ago

0 Scott Bryson 10 months ago

TI__Genius 16100 points

Conor,

You have correctly used a pull-up resistor on the open-drain output of DRV5013. The output pin is typically able to sink about 30 mA (assuming you don't have a thermal dissipation problem), so even if you could use a 38V supply, we would only expect to need 3.8 mA maximum due to the pull-up resistor.

With your filter configuration, you won't be able to use the full output bandwidth of the sensor (10 KHz). Rather, it seems you should expect to hit 95% at about 1.2 msec. You won't want your input field changing any faster than this or you may not be able to fully detect each transition.

The SN74LVC3G17 accepts voltages up to 5.5V, so obviously you cannot set VCC above this level. While you may use this device to translate to a 3.3 V output, DRV5013 can operate with a VCC voltage as low as 2.5 V, so you could create a 3.3V output directly from the sensor.

For the bypass capacitor 0.01 uF is the minimum needed here, but there is an example application drawing which uses 0.1 uF, and this is perfectly acceptable, as it is larger than the minimum requirement.

Thanks,

Scott

0 Conor 10 months ago in reply to Scott Bryson

Mastermind 9020 points

Hi Scott,

Scott Bryson said:
With your filter configuration, you won't be able to use the full output bandwidth of the sensor (10 KHz). Rather, it seems you should expect to hit 95% at about 1.2 msec.

How was the above calculated? 95% probably means 3τ. If I understand correctly, it takes about 0.2ms to stand up 95%.
■ 3τ = 3CR = 3 x 27kΩ x 2700pF = 0.218ms

Scott Bryson said:
DRV5013 can operate with a VCC voltage as low as 2.5 V, so you could create a 3.3V output directly from the sensor.

Is there a reference circuit for output to 3.3 V when VCC is set to 2.5 V?

Thanks,

Conor

+1 Scott Bryson 10 months ago in reply to Conor

TI__Genius 16100 points

Conor,

When I responded yesterday I ran a simulation off the 38V supply case to confirm the rise time. I had made an arithmetic error and I'm glad you caught it. The correct estimate should have been 0.2 ms instead of 1.2 ms.

Running with a square wave input at 500 Hz, I got the following plot, and this confirms your calculation.

For a 3.3V output, the device is an open-drain meaning the VOH level is set by the pull-up voltage. This should always be set the same as Vcc. If you want 3.3V at the output, you would power the device with Vcc = 3.3 V and connect your pull-up accordingly.

Thanks,

Scott

0 Conor 10 months ago in reply to Scott Bryson

Mastermind 9020 points

Hi Scott,

Thank you. Current limiting is implemented on a cycle-by-cycle basis, so it is not a latching operation. Also, OVP also returns to running mode once the OVP region is exited, correct? I am concerned whether there are any protection functions that require external control for the return, such as turning off the enable and restarting, etc., in the method of return.

Conor

0 Scott Bryson 10 months ago in reply to Conor

TI__Genius 16100 points

Conor,

The recovery for the various device protections are shown here:

So for the over current or over voltage conditions, it should return to normal behavior when the fault condition is corrected.

Thanks,

Scott

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DRV5013: Schematic Review Request for DRV5013 and SN74LVC3G17