AD5547 Просмотр технического описания (PDF) - Analog Devices

Номер в каталоге

Компоненты Описание

производитель

AD5547

Dual-Current Output, Parallel Input, 16-/14-Bit Multiplying DACs with 4-Quadrant Resistors

Analog Devices 

AD5547/AD5557

APPLICATIONS INFORMATION

UNIPOLAR MODE

2-Quadrant Multiplying Mode, VOUT = 0 V to –VREF

The AD5547/AD5557 DAC architecture uses a current-steering

R-2R ladder design that requires an external reference and op

amp to convert the unipolar mode of the output voltage to

VOUT = −VREF × D/65,536 (AD5547)

(1)

VOUT = −VREF × D/16,384 (AD5557)

(2)

where D is the decimal equivalent of the input code.

Data Sheet

In this case, the output voltage polarity is opposite the VREF

polarity (see Figure 21). Table 7 shows the negative output vs.

code for the AD5547.

Table 7. AD5547 Unipolar Mode Negative Output vs. Code

D in Binary

1111 1111 1111 1111

1000 0000 0000 0000

0000 0000 0000 0001

0000 0000 0000 0000

VOUT (V)

–VREF (65,535/65,536)

–VREF/2

–VREF (1/65,536)

0

+5V

C1

1µF

2

C2

U3 ADR03

0.1µF VIN

5

TRIM

6

VOUT

+2.5V

GND

VREFA

4

R1A

RCOMA

ROFSA

RFBA

C6

C3

0.1µF

16/14 DATA

VDD R1

R2

AD5547/AD5557

U1

ROFS RFB

2.5V

IOUTA

16-/14-BIT

AGNDA

WR LDAC RS MSB A0, A1

WR

LDAC

2

RS

MSB

A0, A1

6.8pF

+V

AD8628

–V

VOUTA

–2.5V TO 0V

C4

0.1µF

C5

1µF

–5V

Figure 21. Unipolar 2-Quadrant Multiplying Mode, VOUT = 0 to –VREF

Rev. D | Page 14 of 20

Share Link: