REV. D
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a
Variable Resolution,
Resolver-to-Digital Converter
AD2S83
GENERAL DESCRIPTION
The AD2S83 is a monolithic 10-, 12-, 14- or 16-bit tracking
resolver-to-digital converter.
The converter allows users to select their own resolution and dy-
namic performance with external components. The converter allows
users to select the resolution to be 10, 12, 14 or 16 bits and to
track resolver signals rotating at up to 1040 revs per second
(62,400 rpm) when set to 10-bit resolution.
The AD2S83 converts resolver format input signals into a paral-
lel natural binary digital word using a ratiometric tracking con-
version method. This ensures high noise immunity and tolerance of
long leads allowing the converter to be located remote from the
resolver.
The position output from the converter is presented via 3-state
output pins which can be configured for operations with 8- or
16-bit bus. BYTE SELECT, ENABLE and INHIBIT pins
ensure easy data transfer to 8- and 16-bit data bus, and outputs
are provided to allow for cycle or pitch counting in external
counters.
A precise analog signal proportional to velocity is also available
and will replace a tachogenerator.
The AD2S83 operates over reference frequencies in the range
0 Hz to 20,000 Hz.
PRODUCT HIGHLIGHTS
High Accuracy Velocity Output. A precision analog velocity
signal with a typical linearity of ±0.1% and reversion error less
than ±0.3% is generated by the AD2S83. The provision of this
signal removes the need for mechanical tachogenerators used in
servo systems to provide loop stabilization and speed control.
Resolution Set by User. Two control pins are used to select
the resolution of the AD2S83 to be 10, 12, 14 or 16 bits allow-
ing optimum resolution for each application.
Ratiometric Tracking Conversion. This technique provides
continuous output position data without conversion delay. It
also provides noise immunity and tolerance of harmonic distor-
tion on the reference and input signals.
Dynamic Performance Set by the User. By selecting exter-
nal resistor and capacitor values the user can determine band-
width, maximum tracking rate and velocity scaling of the
converter to match the system requirements. The component
values are easy to select using the free component selection
software design aid.
MODELS AVAILABLE
Information on the models available is given in the Ordering
Guide.
FUNCTIONAL BLOCK DIAGRAM
FEATURES
Tracking R/D Converter
High Accuracy Velocity Output
High Max Tracking Rate 1040 RPS (10 Bits)
44-Lead PLCC Package
10-, 12-, 14- or 16-Bit Resolution Set by User
Ratiometric Conversion
Stabilized Velocity Reference
Dynamic Performance Set by User
Industrial Temperature Range
APPLICATIONS
DC and AC Servo Motor Control
Process Control
Numerical Control of Machine Tools
Robotics
Axis Control
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700 World Wide Web Site: http://www.analog.com
Fax: 781/326-8703 © Analog Devices, Inc., 1998
A3
RIPPLE
CLOCK
R4
VCO
I/P
TRACKING
RATE
SELECTION
R6
VELOCITY
SIGNAL
INTEGRATOR
I/P
BANDWIDTH
SELECTION
R3
C3
REFERENCE
I/P
HF FILTER
R2
C2
C1
R1
DEMOD
O/P
INTEGRATOR
O/P
DIRECTIONBUSY
DIG
GND
16
DATA BITS
SC1
SC2
DATA
LOAD
BYTE
SELECT
+5V
+12V
–12V
GND
COS
SIG
GND
SIN
AC ERROR O/P
VCO
O/P
C7
AD2S83
R7
3K3
C6
390pF
R8
–12V
+12V
OFFSET ADJUST
R9
R5
C4
C5
R – 2R DAC
PHASE
SENSITIVE
DETECTOR
VCO + DATA
TRANSFER
LOGIC
16-BIT UP/DOWN COUNTER
SEGMENT
SWITCHING
OUTPUT DATA LATCH
A2
A1
ENABLE INHIBIT
