AD7538 View Datasheet(PDF) - Analog Devices

Part Name

Description

Manufacturer

AD7538

LC2MOS Microprocessor-Compatible 14-Bit DAC

Analog Devices 

AD7538

DAC SECTION

Figure 4 shows a simplified circuit diagram for the AD7538

DAC section. The three MSBs of the 14-bit data word are

decoded to drive the seven switches (A to G). The 11 LSBs

of the data word consist of an R-2R ladder operated in a

current steering configuration.

The R-2R ladder current is ⅛ of the total reference input

current. ⅞ current flows in the parallel ladder structure.

Switch A to Switch G steer equally weighted currents between

IOUT and AGND.

Because the input resistance at VREF is constant, it may be driven

by a voltage source or a current source of positive or negative

polarity.

VREF

R

R

R

2R 2R 2R 2R 2R 2R 2R

2R 2R

G

F

E

D

C

B

A

S10 S9

2R

S0

2R

R/4

Figure 4. Simplified Circuit Diagram for the AD7538 DAC Section

RFB

IOUT

AGND

Rev. B | Page 9 of 16

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