Application information

TSA1203

16/30

8.2

References and common mode connection

VREFM must always be connected directly to ground externally for most applications.

8.2.1

Internal reference and common mode

In the default configuration, the ADC operates with its own reference and common mode

voltages generated by its internal bandgap. It is recommended to decouple the VREFP and

INCM pins in order to minimize low and high frequency noise (see Figure 23).

Figure 23. Internal reference and common mode setting

8.2.2

External reference and common mode

Each of the voltages VREFP, VREFM and INCM can be fixed externally to better fit the

application needs (refer to Table 5: Operating conditions on page 7 for min/max values). It is

possible to use an external reference voltage device for specific applications requiring even

better linearity, accuracy or enhanced temperature behavior.

The VREFP and VREFM voltages set the analog dynamic range at the input of the converter

that has a full scale amplitude of 2*(VREFP-VREFM).

The INCM voltage is half the value of VREFP-VREFM.

The best signal-to-noise performance is achieved with a dynamic range at its maximum

value. To obtain this, VREFM can be connected to GND, and VREFP can be set up to 1.5 V

maximum. However, signal to noise performance is a trade-off with the THD, with a

possibility of degraded THD under these conditions.

To obtain the highest performance from the TSA1203 device, we recommend implementing

the configuration shown in Figure 24 with the STMicroelectronics TS821 or TS4041-1.2

Vref.

TSA1203

VIN

VINB

VREFM

0.89V

VREFP

330pF

4.7

μF

10nF

INCM

330pF

4.7

μF

10nF

0.46V

Obsolete

Product(s)

- Obsolete

Product(s)