ADS7959-Q1: Input inquiry

Renan Santos Adriano

Mastermind 19830 points

Part Number: ADS7959-Q1

Hello Team,

My Custome would like to know whether ADS7959QDBTRQ1 has input clamp diodes at each channel? and what is the input impedance at each channel at power off condition?

Regards,

_Renan

over 4 years ago

0 Cynthia over 4 years ago

TI__Mastermind 24970 points

Hello,

Yes, the inputs have an protective diode structure, that turn on when the AIN > AVDD. During this case, the current is redirected to the AVDD, thus the supply source will need to be able to sink current.

During this case, the input current must also be limited to 2mA.

Regards

Cynthia

0 Renan Santos Adriano over 4 years ago in reply to Cynthia

TI__Mastermind 19830 points

Hello Cynthia,

Thank you for this response. Can you provide what is the input resistance of a channel in the power-off condition of ADS7959QDBTRQ1?

Regards,

Renan

0 Cynthia over 4 years ago in reply to Renan Santos Adriano

TI__Mastermind 24970 points

The input resistance of the analog input in this case would be equivalent to a diode when conducting.

Regards

Cynthia

0 Renan Santos Adriano over 4 years ago in reply to Cynthia

TI__Mastermind 19830 points

Hello Cynthia,

What is the value of input impedance at the power-off condition at each channel? Diode resistance is not given in the datasheet. Kindly help us in getting the value (number).

Regards,

Renan

0 Cynthia over 4 years ago in reply to Renan Santos Adriano

TI__Mastermind 24970 points

This information is not available.

I would suggest following previous advice, when the AIN > AVDD, the input current is redirected to the AVDD, thus the supply source will need to be able to sink current. During this case, the input current must also be limited to 2mA by external protection. Do not consider the device impedance for this

Regards

Cynthia

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ADS7959-Q1: Input inquiry