TLV1543C, TLV1543I, TLV1543M

3.3V 10BIT ANALOGTODIGITAL CONVERTERS

WITH SERIAL CONTROL AND 11 ANALOG INPUTS

SLAS072E − DECEMBER 1992 − REVISED JANUARY 2004

17

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APPLICATION INFORMATION

simplified analog input analysis

within 1/2 LSB can be derived as follows:

The capacitance charging voltage is given by

(

)

(1)

Where:

The final voltage to 1/2 LSB is given by

(2)

(

)

(3)

and

(4)

Therefore, with the values given the time for the analog input signal to settle is

(5)

This time must be less than the converter sample time shown in the timing diagrams.

Rs

ri

VS

VC

1 k

Ω MAX

Driving Source†

TLV1543

Ci

VI

VI = Input Voltage at A0 −A10

VS = External Driving Source Voltage

Rs = Source Resistance

ri = Input Resistance

Ci = Input Capacitance

† Driving source requirements:

• Noise and distortion for the source must be equivalent to the

resolution of the converter.

• Rs must be real at the input frequency.

Figure 17. Equivalent Input Circuit Including the Driving Source

60 pF MAX