ADC12H034 datasheet(30/41 Pages) NSC

30 / 41 page

Application Hints (Continued)

CH0, CH2, CH4, and CH6 can be assigned to the MUX-

OUT1 pin in the differential configuration, while CH1, CH3,

CH5, and CH7 can be assigned to the MUXOUT2 pin. In the

differential configuration, the analog inputs are paired as

follows: CH0 with CH1, CH2 with CH3, CH4 with CH5 and

CH6 with CH7. The A/DIN1 and A/DIN2 pins can be as-

signed positive or negative polarity.

With the single-ended multiplexer configuration CH0 through

CH7 can be assigned to the MUXOUT1 pin. The COM pin is

always assigned to the MUXOUT2 pin. A/DIN1 is assigned

as the positve input; A/DIN2 is assigned as the negative

input. (See Figure 10).

The Multiplexer assignment tables for the ADC12030,2,4,8

(Tables 2, 3, 4) summarize the aforementioned functions for

the different versions of A/Ds.

2.1 Biasing for Various Multiplexer Configurations

Figure 11 is an example of biasing the device for

single-ended operation. The sign bit is always low. The

digital output range is 0 0000 0000 0000 to 0 1111 1111 1111.

One LSB is equal to 1 mV (4.1V/4096 LSBs).

Differential

Configuration

Single-Ended

Configuration

01135440

A/DIN1 and A/DIN2 can be assigned as the + or − input

01135441

A/DIN1 is + input

A/DIN2 is − input

FIGURE 10.

01135446

FIGURE 11. Single-Ended Biasing

ADC12H034 Datasheet(PDF) 30 Page - National Semiconductor (TI)