MSP430FR5870: MSP430FR5870 's ADC input impedance

Nicole Han

Intellectual 2230 points

Part Number: MSP430FR5870

Hi, team,

Want to check with you, what the input impedance of MSP430FR5870's ADC input (pin41~48) at power on and off?

Thanks!

over 9 years ago

0 Clemens Ladisch over 9 years ago

Guru 325780 points

Section 28.2.6.3 of the User's Guide says:

When SAMPCON = 0, all Ax inputs are high impedance.

This section also describes how an input behaves when SAMPCON = 1; the C_I/R_I values can be found in table 5-22 of the datasheet.

0 Keith Barkley over 9 years ago

Guru 43775 points

Be careful applying power to a pin with the power not applied to the supply pins. The internal ESD diodes can actually turn the chip on.

0 Ryan Brown1 over 9 years ago

TI__Guru**** 223287 points

Hi Nicole,

All port pins are high-impedance inputs at start-up so you're going to have several thousand to beyond a million kOhms. e2e.ti.com/.../115557

Regards,
Ryan

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MSP430FR5870: MSP430FR5870 's ADC input impedance