DAC8871 Datasheet, PDF(14/19 Page) Burr-Brown (TI) – 16-Bit, Single-Channel, ±18V Output (Unbuffered), Ultra-Low Power, Serial Interface DIGITAL-TO-ANALOG CONVERTER

English

English German Russian Spanish Italian Polish Chinese Japanese Korean French Portuguese	Language :

DAC8871 Datasheet, PDF (14/19 Pages) Burr-Brown (TI) – 16-Bit, Single-Channel, ±18V Output (Unbuffered), Ultra-Low Power, Serial Interface DIGITAL-TO-ANALOG CONVERTER

◁

DAC8871

SBAS396 â JUNE 2007

THEORY OF OPERATION

www.ti.com

GENERAL DESCRIPTION

The DAC8871 is a 16-bit, single-channel, serial-input, voltage-output DAC. It operates from a dual power supply

ranging from Â±13.5V to Â±19.8V, and typically consumes 10ÂµA. The output range is from VREFL to VREFH. Data are

written to this device in a 16-bit word format, via an SPI serial interface. To ensure a known power-up state, the

DAC8871 is designed with a power-on reset function. After power on, the state of the RSTSEL pin sets the

value of the input register and DAC latch, which sets the output state of the VOUT pin. Refer to the Power-On

Reset and Hardware Reset section for more details.

Kelvin sense connections for the reference and analog ground are also included.

DIGITAL-TO-ANALOG SECTIONS

The DAC architecture consists of two matched DAC sections and is segmented. A simplified circuit diagram is

shown in Figure 38. The four MSBs of the 16-bit data word are decoded to drive 15 switches, E1 to E15. Each

of these switches connects one of 15 matched resistors to either AGND or VREF. The remaining 12 bits of the

data word drive switches S0 to S11 of a 12-bit voltage mode R-2R ladder network.

VOUT

VREFH-F

VREFH-S

VREFL-F

VREFL-S

S11

E15

12-Bit R-2R Ladder

Four MSBs Decoded into

15 Equal Segments

Figure 38. DAC Architecture

OUTPUT RANGE

The output of the DAC is:

V OUT

(VREFH * VREFL) Code

65536 ) VREFL

(1)

Where Code is the decimal data word loaded to the DAC latch.

For example, if VREFH is +10V, and VREFL is â10V, the range of VOUT is from â10V (code = 0000h) to +10V (code

= FFFFh).

The range of VREFL is from â18V to (VREFH â 1.25V), and the range of VREFH is 0V to +18V. The output from the

DAC8871 can be unipolar (from 0V to +18V) or bipolar by setting the proper VREFL and VREFH values.

Submit Documentation Feedback

▷