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
Resolver-to-Digital Converter
AD2S83
FUNCTIONAL BLOCK DIAGRAM
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 dynamicperformance 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 parallel natural binary digital word using a ratiometric tracking conversion 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.
REV. E
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.
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 allowing 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 distortion on the reference and input signals.
Dynamic Performance Set by the User. By selecting external
resistor and capacitor values the user can determine bandwidth, 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.
SenseLogic HI When Position O/P Changing
Width150350ns
LoadUse Additional Pull-Up (See Figure 2)1LSTTL
DIRECTION
6
SenseLogic HI Counting Up
Max Load3LSTTL
RIPPLE CLOCK
6
SenseLogic HI
WidthDependent on Input Velocity300ns
ResetBefore Next Busy
Load3LSTTL
DIGITAL INPUTS
Input High Voltage, V
Input Low Voltage, V
IH
IL
DIGITAL INPUTS
Input High Current, I
Input Low Current, I
IH
IL
DIGITAL INPUTS
Low Voltage, V
Low Current, I
IL
IL
DIGITAL OUTPUTS
High Voltage, V
Low Voltage, V
NOTES
1
Angular accuracy is not guaranteed <50 Hz reference frequency.
2
Linearity derates from 500 kHz–1000 kHz @ 0.0017%/kHz.
3
Refer to Definition of Linearity, “The AD2S83 as a Silicon Tachogenerator.”
4
Worst case reversion error at temperature extremes.
5
Velocity output offset dependent on value for R6.
6
Refer to timing diagram.
7
Busy pulse guaranteed up to a VCO rate of 900 kHz.
All min and max specifications are guaranteed. Specifications in boldface are tested on all production units at final electrical test.
Specifications subject to change without notice.
OH
OL
. Logic LO to Activate;
to +V
S
No Connect for Normal Operation
. Logic LO Allows
to +V
S
Data to be Loaded into the
Counters from the Data Lines
Open-Loop GainAt 10 kHz576063dB
Dead Zone Current (Hysteresis)90100110nA/LSB
Input Offset Voltage15mV
Input Bias Current60150nA
Output Voltage Range8V
VCO
Maximum Rate1.1MHz
VCO Rate+ve DIR8.258.508.75kHz/µA
–ve DIR8.258.508.75kHz/µA
VCO Power Supply Sensitivity
Rate+V
–V
S
S
+0.5%/V
–0.5%/V
Input Offset Voltage3mV
Input Bias Current1250nA
Input Bias Current Tempco+0.22nA/°C
Linearity of Absolute Rate
AD2S83AP
0 kHz–500 kHz±0.150.25% FSR
0.5 MHz–1 MHz±0.251.0% FSR
AD2S83IP
0 kHz–500 kHz±0.250.5% FSR
0.5 MHz–1 MHz±0.251.0% FSR
Reversion Error
AD2S83AP±0.51.0% Output
AD2S83IP±1.01.5% Output
POWER SUPPLIES
Voltage Levels
+V
–V
+V
S
S
L
+11.4+12.6V
–11.4–12.6V
+4.5+5+V
S
V
Current
±I
S
±I
S
±I
L
All min and max specifications are guaranteed. Specifications in boldface are tested on all production units at final electrical test.
Specifications subject to change without notice.
±VS @ ±12 V±1223mA
±VS @ ±12.6 V±1930mA
+VL @ ±5.0 V±0.51.5mA
ORDERING GUIDE
TemperaturePackagePackage
ModelRangeAccuracyDescriptionOption
AD2S83AP–40°C to +85°C8 arc minPlastic Leaded Chip CarrierP-44A
AD2S83IP–40°C to +85°C8 arc minPlastic Leaded Chip CarrierP-44A
High Impedance State
Logic LO—Presents Active Data
to the Output Pins
28BYTE SELECTLogic HI—Most Significant Byte to
DB1–DB8
Logic LO—Least Significant Byte
to DB1–DB8
30INHIBITLogic LO Inhibits Data Transfer
to Output Latches
31DIGITAL GNDDigital Ground
32, 33 SC2–SC1Select Converter Resolution
34DATA LOADLogic LO DB1–DB16 Inputs
Logic HI DB1–DB16 Outputs
35COMPLEMENTActive Logic LO
36BUSYConverter Busy, Data not Valid
While Busy HI
37DIRECTIONLogic State Defines Direction of
Input Signal Rotation
38RIPPLE CLOCKPositive Pulse When Converter Output
Changes from 1s to All 0s or Vice Versa
39–V
S
Negative Power Supply
40VCO I/PVCO Input
41VCO O/PVCO Output
42INTEGRATOR O/PIntegrator Output
43INTEGRATOR I/PIntegrator Input
44DEMOD I/PDemodulator Input
CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily
accumulate on the human body and test equipment and can discharge without detection. Although
the AD2S83 feature proprietary ESD protection circuitry, permanent damage may occur on devices
subjected to high-energy electrostatic discharges. Therefore, proper ESD precautions are
recommended to avoid performance degradation or loss of functionality.
The power supply voltages connected to +VS and –VS pins
should be +12 V dc and –12 V dc and must not be reversed.
The voltage applied to V
can be +5 V dc to +VS.
L
It is recommended that the decoupling capacitors are connected
in parallel between the power lines +V
, –VS and ANALOG
S
GROUND adjacent to the converter. Recommended values are
100 nF (ceramic) and 10 µF (tantalum). Also capacitors of
100 nF and 10 µF should be connected between +V
and
L
DIGITAL GROUND adjacent to the converter.
When more than one converter is used on a card, separate decoupling capacitors should be used for each converter.
The resolver connections should be made to the SIN and COS
inputs, REFERENCE INPUT and SIGNAL GROUND as
shown in Figure 11 and described in the Connecting the
Resolver section.
The two signal ground wires from the resolver should be joined
at the SIGNAL GROUND pin of the converter to minimize the
coupling between the sine and cosine signals. For this reason it
is also recommended that the resolver is connected using individually screened twisted pair cables with the sine, cosine and
reference signals twisted separately.
SIGNAL GROUND and ANALOG GROUND are connected
internally. ANALOG GROUND and DIGITAL GROUND
must be connected externally and as close to the converter as
possible.
The external components required should be connected as
shown in Figure 1.
CONVERTER RESOLUTION
Two major areas of the AD2S83 specification can be selected by
the user to optimize the total system performance. The resolution of the digital output is set by the logic state of the inputs
SC1 and SC2 to be 10, 12, 14 or 16 bits; and the dynamic characteristics of bandwidth and tracking rate are selected by the
choice of external components.
The choice of the resolution will affect the values of R4 and R6
which scale the inputs to the integrator and the VCO respectively (see Component Selection section). If the resolution is
changed, then new values of R4 and R6 must be switched into
the circuit.
Note: When changing resolution under dynamic conditions, do
it when the BUSY is low, i.e., when data is not changing.
SIN
SIG GND
COS
GND
RIPPLE
CLOCK
+12V
–12V
DATA
LOAD
SC1
A1
SEGMENT
SWITCHING
A2
16-BIT UP/DOWN COUNTER
ENABLE
SC2
R - 2R DAC
OUTPUT DATA LATCH
16 DATA BITS
Figure 1. Connection Diagram
AC ERROR O/P
A3
AD2S83
BYTE
SELECT
HF FILTER
C1
R1
5V
GND
R2
C2
PHASE
SENSITIVE
DETECTOR
REFERENCE
I/P
C3
DEMOD
O/P
VCO + DATA
TRANSFER
LOGIC
DIRECTIONBUSYDIG
R3
R4
INTEGRATOR
O/P
INHIBIT
OFFSET ADJUST
+12V
INTEGRATOR
VCO
I/P
VCO
O/P
R9
R8
BANDWIDTH
SELECTION
I/P
R6
C7
150pF
R7
3K3
C6
390pF
–12V
C5
R5
C4
TRACKING
RATE
SELECTION
VELOCITY
SIGNAL
–6–
REV. E
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