PGA400-Q1 Accuracy

RAJESH KUMAR PURNEA

Other Parts Discussed in Thread: PGA400-Q1

Hi,

I am planning to consider automotive grade pressure sensor signal conditioner, PGA400-Q1 to measure capacitance in range of 20pF to 300pF.

I would like to know following regarding PGA400-Q1:

1. What is the best achievable accuracy?

2. In the datasheet, in section 7.2 Capacitive Sensor Interface diagram, two capacitors are indicated - Cp & Cr, where Cp is the varying portion of the capacitive sensor and Cr is the fixed portion of that. Could you shed some light on selection of Cr values? Do we have to connect Cr on the sensor or it should be on testing pcb?

3. Finally as requirement is for automotive product, would like to know how long this device will be active? Is there specified extended product longevity period for at least 10 years?

Thanks & Regards,

Rajesh

over 9 years ago

Mayrim Verdejo over 9 years ago

TI__Genius 15760 points

Hi Rajesh,

Thank you for using TI E2E Forums. I have moved this question to the Automotive forum. They support this device.

Mayrim

Eric Hackett over 9 years ago in reply to Mayrim Verdejo

TI__Guru 60242 points

Mayrim,

Thank you for making note of this.

Rajesh,

The appropriate applications engineer has been notified of your question. They should be getting back to you with a response shortly.

Regards,

Eric Hackett

RAJESH KUMAR PURNEA over 9 years ago in reply to Eric Hackett

Intellectual 380 points

Hi Eric,

Is there any response for my queries?

It has been a long time to get these queries answered, please look into this.

Awaiting your response.

Regards,

Rajesh

Carter Liu over 9 years ago in reply to RAJESH KUMAR PURNEA

TI__Expert 5425 points

Hi Rajesh,

I have asked our team to follow up,and I will be here waiting for their reply,and learn with you together.

Regards

Carter

RAJESH KUMAR PURNEA over 9 years ago in reply to Carter Liu

Intellectual 380 points

Hi Carter,

It is nice to see you here.

Hope your effort brings the response faster.

Regards,

Rajesh

Clancy Soehren over 9 years ago

TI__Mastermind 23810 points

Rajesh,

First, what package are you planning on using? WCSP or QFN?

1. The accuracy and noise depends on the settings you're using. The easiest method is to do some measurements yourself. Some of the data we have shows that with a 256us decimator output, across temperature with Cr = 10pF and Cp ranging of 310pF the standard deviation of ADC counts is less than 2 ADC counts. When Cp is 14pF, this rises to about 5 ADC counts.

2. You could put it on the PCB if it isn't part of the sense element. Table 6-2 in the datasheet has some guidelines for Cp and Cr values.

3. This device is still in production, and TI understands the long lifetime needed for automotive parts. Generally TI will keep producing a device if there are orders for it and there will be notice if it does go to end of life.

Automotive (Read-Only)

Automotive Forum (Read-Only)

PGA400-Q1 Accuracy