TSA1204(2006) View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

TSA1204
(Rev.:2006)

Dual channel 12-bit 20Msps 120mW A/D converter

STMicroelectronics 

Application information

TSA1204

8.2

8.2.1

References and common mode connection

VREFM must always be connected externally.

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

1.03V

330pF 10nF 4.7μF

VIN VREFP

TSA1204

INCM

0.57V

330pF 10nF 4.7μF

VINB VREFM

8.2.2

External reference and common mode

Each of the voltages VREFM, VREFP and INCM can be fixed externally to better fit to 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 linearity and distortion performance is achieved with a dynamic range above 2 Vpp

and by increasing the VREFM voltage instead of lowering the VREFP one.

To obtain the highest performance from the TSA1204 device, we recommend implementing

the configuration shown in Figure 24 with the STMicroelectronics TS821or TS4041-1.2 Vref.

Figure 24. External reference setting

1kΩ

VCCA VREFP

VIN

TSA1204

VINB VREFM

330pF 10nF 4.7μF

TS821

TS4041

external

reference

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