STM32W108CB datasheet(218/278 Pages) STMICROELECTRONICS

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Analog-to-digital converter

STM32W108HB STM32W108CC STM32W108CB STM32W108CZ

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Doc ID 16252 Rev 14

Analog-to-digital converter

The STM32W108 analog-to-digital converter (ADC) is a first-order sigma-delta converter

with the following features:

●

Resolution of up to 12 bits

●

Sample times as fast as 5.33 µs (188 kHz)

●

Differential and single-ended conversions from six external and four internal sources

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Two voltage ranges (differential): -VREF to +VREF, and –VDD_PADS to +VDD_PADS

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Choice of internal or external VREF: internal VREF may be output

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Digital offset and gain correction

●

Dedicated DMA channel with one-shot and continuous operating modes

Figure 51 shows the basic ADC structure.

Figure 51.

ADC block diagram

For the STM32W108CC and STM32108CZ devices, the input range selection block is not present on the N Input.

While the ADC Module supports both single-ended and differential inputs, the ADC input

stage always operates in differential mode. Single-ended conversions are performed by

connecting one of the differential inputs to VREF/2 while fully differential operation uses two

external inputs.

Note:

This note only applies to STM32W108xB. In high voltage mode, input buffers (with 0.25 gain

only) may experience long term drift of its input offset voltage that affects ADC accuracy. In

these cases, only the 1.2V input range mode of the ADC should be used. If measurement of

signals >1.2V is required, then external attenuation should be added.

Note:

For STM32W108CC and STM32108CZ, high voltage mode is supported only in single

mode. It is also required by the software to periodically set to 1 bit HVSELN in the register

ADC_CR.

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