a
FEATURES
Monolithic (BiMOS ll) Tracking R/D Converter
Ratiometric Conversion
Low Power Consumption: 300 mW Typ
Dynamic Performance Set by User
Velocity Output
ESD Class 2 Protection (2,000 V Min)
AD2S81A
28-Lead DIP Package
Low Cost
AD2S82A
44-Lead PLCC Package
10-, 12-, 14- and 16-Bit Resolution Set by User
High Max Tracking Rate 1040 RPS (10 Bits)
VCO Output (Inter LSB Output)
Data Complement Facility
Industrial Temperature Range
APPLICATIONS
DC Brushless and AC Motor Control
Process Control
Numerical Control of Machine Tools
Robotics
Axis Control
GENERAL DESCRIPTION
Variable Resolution, Monolithic
Resolver-to-Digital Converters
AD2S81A/AD2S82A
AD2S82A FUNCTIONAL BLOCK DIAGRAM
DEMOD DEMOD INTEGRATOR
I/P
O/P
I/P
AD2S82A
SIN I/P
SIGNAL
GND
COS I/P
ANALOG
GND
RIPPLE
CLK
+12V
–12V
COMP
DATA
LOAD
A1
SEGMENT
SWITCHING
A2
PHASE
SENSITIVE
DETECTOR
R-2R
DAC
INTEGRATOR
O/P
A3
AC ERROR
O/P
VCO I/P
INHIBIT
VCO O/P
+5V
16-BIT
UP/DOWN COUNTER
VCO DATA
TRANSFER
LOGIC
OUTPUT DATA LATCH
SC2
SC1
ENABLE
BUSY DIR
BYTE
SELECT
DIGITAL
GND
16 DATA BITS
An analog signal proportional to velocity is also available and
can be used to replace a tachogenerator.
PRODUCT HIGHLIGHTS
Monolithic.
A one-chip solution reduces the package size re-
quired and increases the reliability.
Resolution Set by User.
Two control pins are used to select
the resolution of the AD2S82A to be 10, 12, 14 or 16 bits al-
lowing the user to use the AD2S82A with the optimum resolu-
tion for each application.
Ratiometric Tracking Conversion.
Conversion technique
provides continuous output position data without conversion
delay and is insensitive to absolute signal levels. It also provides
good noise immunity and tolerance to harmonic distortion 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 external com-
ponents required are all low cost, preferred value resistors and
capacitors, and the component values are easy to select using
the simple instructions given.
Velocity Output.
An analog signal proportional to velocity is
available and is linear to typically one percent. This can be used
in place of a velocity transducer in many applications to provide
loop stabilization in servo controls and velocity feedback data.
Low Power Consumption.
Typically only 300 mW.
MODELS AVAILABLE
The AD2S82A is a monolithic 10-, 12-, 14- or 16-bit tracking
resolver-to-digital converter contained in a 44-lead J leaded
PLCC package. Two extra functions are provided in the new
surface mount package–COMPLEMENT and VCO output.
The AD2S81A is a monolithic 12-bit fixed resolution tracking
resolver-to-digital converter packaged in a 28-lead DIP.
The converters allow users to
select their own dynamic performance
with external components.
This allows the users great flexibility in
defining the converter that best suits their system requirements.
The AD2S82A 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 AD2S81A and AD2S82A convert resolver format input
signals into a parallel natural binary digital word using a ratio-
metric tracking conversion method. This ensures high-noise
immunity and tolerance of lead length when the converter is
remote from the resolver.
The output word is in a three-state digital logic form available in
two bytes on the 16 output data lines for the AD2S82A and on
eight output data lines for the AD2S81A. BYTE SELECT,
ENABLE
and
INHIBIT
pins ensure easy data transfer to 8- and
16-bit data buses, and outputs are provided to allow for cycle or
pitch counting in external counters.
REV. B
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
Information on the models available is given in the Ordering
Guide.
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
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