DAC8M_15 Datasheet, PDF (1/2 Pages) Analog Devices – 4-Quadrant Multiplication

GENERAL DESCRIPTION
The DAC-M multiplying digital-to-analog converters are the smallest
high performance units of this type currently available. These devices
are completely self-contained, compatible with DTL and TTLlogic,
and include reference buffer amplifiers and output amplifier within the
small (2" X 2" X 0.4") module.
The DAC-M is available in 12-bit and 8-bit versions, with binary input
logic coding. The analog output voltage is the algebraic product of
the analog (reference) input and the digital input number, over the
full four quadrants.
FEATURES
The design utilizes Analog Devices' new IlDAC Model AD555 quad
voltage switch, with a precision R-2R ladder network. The package
has been designed with an eye to minimum board area, as well as
4-Quadrant Multiplication
Only One Reference Polarity
allowing board spacing of 0.5". Electrical connection arrangement is
or Phase Needed
OBSOLETE compatible with automated assembly requirements.
EXCEPTIONAL PERFORMANCE OVER TEMPERATURE
Both versions (8- and 12-bit) of the DAC-M perform exceptionally
well over temperature variations. For instance, the DAC-12M can be
operated in environments varying as much as 20°C in temperature,
without having either gain or zero error exceed one LSB! Spectacular
performance when compared to that of most other similar products
currently on the market, some of which go out of specification after
temperature shift of only 2°C!
TRUE FOUR-QUADRANT OPERATION
The output of any DAC can be considered to be the product of the
reference and the digital number input. Most DAC's, however, are
designed for fixed and highly stable reference voltage input. This
limits the applicability to those situations where a variable reference
is not required.
No Trimming
Operates from :!:15V
No External Amplifiers Needed
Exceptional Performance
over Temperature
A true multiplying DAC, such as the DAC-M, is designed to allow use
of ac (or varying dc) reference voltages. The DAC-M can be thought of
as a digitally controlled voltage divider, in which voltages of different
polarity (or phase) can be applied to the opposite ends of the resistance
element, and the positi~n of the slider contact is digitally set by the
logic input. When used with an offset binary input code, the "slider"
APPLICATIONS
position is effectively zero center, and the result is a true four-quadrant
multiplication, with maintenance of both arithmetic and algebraic
sign ru les.
Digital COntrol of
Synchros/Resolvers
The DAC-M can be operated in 4 quadrants with only one polarity of
reference input voltage, since the built-in buffer and inverter provide
for generation of the second reference signal. The flexible terminal
arrangement allows the user to supply both reference polarities,
if he prefers.
APPLICATIONS
Multiplying DAC's are used extensively in the construction of digital-
to-synchro converters for use in computer-controlled shaft positioning,
in fields as diverse as aircraft control systems, numerically controlled
machine tools, and the setting of final control elements (such as
valves) in chemical process plants. The ac performance of the DAC-M
qualifies it for service as a digitally-set variable gain amplifier, as well as
in computer graphics, in vector generation and point plotting systems.
It is also useful as the basis of a programmable level signal generator,
for use in computer controlled automatic test systems.
CO81b-1-4176
PRINTED IN USA
Numerically Controlled
Machines
CRT Graphic Displays
Radar PPI Displays
Digital Control of
Amplifier Gain
ANALOG III
LillI DEVICES~
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