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AS1545

Datasheet - D e t a i l e d D e s c r i p t i o n

Single-Ended Mode

The AS1545 consists of 12 single-ended analog input channels with range that can be programmed to be either 0 to

Note: In applications where the signal source has high impedance, it is recommended to buffer the analog input

before applying it to the ADC.

If the sampling analog input is bipolar, the internal reference of the ADC can be used to externally bias up this signal to

make it correctly formatted for the ADC. Figure 36 shows the connecting diagram when operating the ADC in single-

ended mode.

Figure 36. Single-Ended Mode Connection Diagram

Figure 37. Definition of Single-Ended Input

Fully Differential Mode

The AS1545 consists of six differential analog input pairs. Figure 38 defines the fully differential analog input of the

AS1545. The amplitude of the differential signal is the difference between the signals applied to the AIN+ and AIN- pins

in each differential pair (AIN+ - AIN-). These pins should be simultaneously driven by two signals each of amplitude

The common mode is the average of the two signals and is therefore the voltage on which the two inputs are centered.

(EQ 1)

Althought fully differential operation with phase between inputs of 180° is recommanded, non true differential signals

can also be applied.

+

-

+

-

R

3R

R

R

REFA/

REFB

AIN0 to BIN5

-1.25V

0V

+1.25V

0V

+2.5V

10nF

4.7µF

10

Ω

0 < AIN < VDD

RANGE = 0

0 < AIN < VDD

RANGE = 1

VIN

VIN

tt

VREF

2VREF