ADS1148-Q1: Digital signal usage

Brennan Hartigan

Part Number: ADS1148-Q1
Other Parts Discussed in Thread: ADS1148

Hello TI,

Are pin connections required for RESETn, DRDYn, and START? Is there a default high/low these pins can be held to if they don't need to be connected to a controller?

Regards,

1 month ago

0 Bryan Lizon86 1 month ago

TI__Guru 58961 points

Hi Brennan Hartigan

No these pin connections are not required

You can tie RESET high, otherwise tying this pin low holds the device in reset

You can leave DRDY floating because it is a digital output (see section 10.1.6)

You should tie START high if you want to control conversions using commands (see section 9.4.4)

-Bryan

0 Brennan Hartigan 1 month ago in reply to Bryan Lizon86

Prodigy 40 points

Bryan,

Thank you!

What is the maximum number of 4-wire RTDs that can be connected to the ADS1148-Q1? Is there any reference design for this?

Regards,

0 Bryan Lizon86 1 month ago in reply to Brennan Hartigan

TI__Guru 58961 points

Hi Brennan Hartigan,

The figure below shows how to connect multiple 4-wire RTDs to an ADC. So the limiting factor is the number of channels. The ADS1148 includes dedicated external reference and IDAC pins so you should be able to implement the scheme as shown below

You can reference our RTD design guide for more info: https://www.ti.com/lit/an/sbaa275a/sbaa275a.pdf?ts=1782423182411&ref_url=https%253A%252F%252Fwww.google.com%252F

-Bryan

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ADS1148-Q1: Digital signal usage