DAC8728_14 Datasheet, PDF (32/56 Pages) Texas Instruments – Octal, 16-Bit, Low-Power, High-Voltage Output, Parallel Input DIGITAL-TO-ANALOG CONVERTER

DAC8728
SBAS466A – JUNE 2009 – REVISED NOVEMBER 2009
www.ti.com
THEORY OF OPERATION
GENERAL DESCRIPTION
The DAC8728 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 to AGND, as shown in Figure 95. This type of architecture
provides DAC monotonicity. The 16-bit binary digital code loaded to the DAC register 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. The output span is 9V with a 1.5V reference, 18V with a 3V
reference, and 30V for a 5V reference when using dual power supplies of ±16.5V and a gain of 6.
REF
R
R
R
To Output
Amplifier
R
R
Figure 95. 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.
32
Submit Documentation Feedback
Product Folder Link(s): DAC8728
Copyright © 2009, Texas Instruments Incorporated