DAC8718 Datasheet, PDF (35/60 Pages) Texas Instruments – Octal, 16-Bit, Low-Power, High-Voltage Output, Serial Input DIGITAL-TO-ANALOG CONVERTER

DAC8718
www.ti.com
SBAS467A – MAY 2009 – REVISED DECEMBER 2009
THEORY OF OPERATION
GENERAL DESCRIPTION
The DAC8718 contains eight DAC channels and eight output amplifiers in a single package. Each channel
consists of a resistor-string DAC followed by an output buffer amplifier. The resistor-string section is simply a
string of resistors, each with a value of R, from REF-x to AGND, as shown in Figure 97. This type of architecture
provides DAC monotonicity. The 16-bit binary digital code loaded to the DAC latch determines at which node on
the string the voltage is tapped off before being fed into the output amplifier. The output amplifier multiplies the
DAC output voltage by a gain of six or four. Using a gain of 6 and power supplies allowing for at least 0.5V
headroom, the output span is 9V with a 1.5V reference, 18V with a 3V reference, and 30V with a 5V reference.
REF-x
R
R
R
To Output
Amplifier
R
R
Figure 97. Resistor String
CHANNEL GROUPS
The eight DAC channels and two Offset DACs are arranged into two groups (A and B) with four channels and
one Offset DAC per group. Group A consists of DAC-0, DAC-1, DAC-2, DAC-3, and Offset DAC-A. Group B
consists of DAC-4, DAC-5, DAC-6, DAC-7, and Offset DAC-B. Group A derives its reference voltage from
REF-A, and Group B derives its reference voltage from REF-B.
Copyright © 2009, Texas Instruments Incorporated
Product Folder Link(s): DAC8718
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