AD7846 데이터 시트보기 (PDF) - Analog Devices

부품명

상세내역

제조사

AD7846

LC2MOS 16-Bit Voltage Output DAC

Analog Devices 

UNIPOLAR BINARY OPERATION

Figure 23 shows the AD7846 in the unipolar binary circuit

configuration. The DAC is driven by the AD586 +5 V reference.

Because RIN is tied to 0 V, the output amplifier has a gain of 2

and the output range is 0 V to +10 V. If a 0 V to +5 V range is

required, RIN should be tied to VOUT, configuring the output

stage for a gain of 1. Table 8 gives the code table for the circuit

of Figure 23.

+15V

+5V

2

6

8 AD586

5

C1

1µF

4

4

VDD

21

VCC

R1

10kΩ

7 VREF+

VOUT 5

AD7846*

RIN 6

VOUT

(0V TO +10V)

8 VREF–

DGND 20

SIGNAL

VSS

GROUND

*ADDITIONAL PINS

OMITTED FOR CLARITY

–15V

Figure 23. Unipolar Binary Operation

AD7846

Table 8. Code Table for Figure 23

Binary Number in DAC Latch

MSB

LSB1

Analog Output (VOUT)

1111 1111 1111 1111

+10 (65,535/65,536) V

1000 0000 0000 0000

+10 (32,768/65,536) V

0000 0000 0000 0001

+10 (1/65,536) V

0000 0000 0000 0000

0V

1 LSB = 10 V/216 = 10 V/65,536 = 152 μV.

Offset and gain can be adjusted in Figure 23 as follows:

• To adjust offset, disconnect the VREF− input from 0 V, load

the DAC with all 0s, and adjust the VREF− voltage until VOUT

= 0 V.

• For gain adjustment, the AD7846 should be loaded with all

1s and R1 adjusted until VOUT = 10 (65,535)/(65,536) =

9.999847 V. If a simple resistor divider is used to vary the

VREF− voltage, it is important that the temperature

coefficients of these resistors match that of the DAC input

resistance (−300 ppm/°C). Otherwise, extra offset errors are

introduced over temperature. Many circuits do not require

these offset and gain adjustments. In these circuits, R1 can

be omitted. Pin 5 of the AD586 can be left open circuit and

Pin 8 (VREF−) of the AD7846 tied to 0 V.

Rev. G | Page 13 of 24

Share Link: