www.docs.chipfind.ru
12-Bit R/D Converter
with Reference Oscillator
AD2S1200
Rev. 0
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 that may result from its use.
Specifications subject to change without notice. No license is granted by implication
or otherwise under any patent or patent rights of Analog Devices. Trademarks and
registered trademarks are the property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
www.analog.com
Fax: 781.326.8703
2003 Analog Devices, Inc. All rights reserved.
FEATURES
Complete monolithic R/D converter
Parallel and serial 12-bit data ports
System fault detection
Absolute position and velocity outputs
Differential inputs
11 arc minutes of accuracy
1,000 rps maximum tracking rate, 12-bit resolution
Incremental encoder emulation (1,024 pulses/rev)
Programmable sinusoidal oscillator on-board
Compatible with DSP and SPI interface standards
204.8 kHz square wave output
Single-supply operation (5.00 V 5%)
-40C to +125C temperature rating
44-lead LQFP package
4 kV ESD protection
GENERAL DESCRIPTION
The AD2S1200 is a complete 12-bit resolution tracking resolver-
to-digital converter, integrating an on-board programmable
sinusoidal oscillator that provides sine wave excitation for
resolvers. An external 8.192 MHz crystal is required to provide
a precision time reference. This clock is internally divided to
generate a 4.096 MHz clock to drive all the peripherals.
The converter accepts 3.6 V p-p 10% input signals, in the
range of 10 kHz to 20 kHz on the Sin and Cos inputs. A Type II
servo loop is employed to track the inputs and convert the input
Sin and Cos information into a digital representation of the
input angle and velocity. The bandwidth of the converter is set
internally to 1.7 kHz with an external 8.192 MHz crystal. The
maximum tracking rate is 1,000 rps.
FUNCTIONAL BLOCK DIAGRAM
04406-
0-
001
REFERENCE
OSCILLATOR
(DAC)
ADC
SinLO
Sin
ANGLE
ANGLE
ADC
CosLO
Cos
EXC
EXC
A
B
NM
SAMPLE
MONITOR
ERROR
MONITOR
(204.8kHz)
CPO
REFBYP
REFOUT
FS1
FS2
XTALOUT
CLKIN
(8.192MHz)
DOS
LOT
DIR
(4.096MHz)
ERROR
ERROR
CALCULATION/
SIGNAL
MONITOR
DEMODULATOR
CS
RD
POSITION
INTEGRATOR
POSITION REGISTER
MULTIPLEXER
DB11
SO
SOE
RDVEL
RESET
DB10
SCLK
DB9DB0
AD2S1200
DATA BUS OUTPUT
VELOCITY REGISTER
ENCODER
EMULATION
SYNTHETIC
REFERENCE
VOLTAGE
REFERENCE
INTERNAL
CLOCK
GENERATOR
CLOCK
DIVIDER
FAULT
INDICATORS
DIGITAL
FILTER
VELOCITY
INTEGRATOR
Figure 1.
AD2S1200
Rev. 0 | Page 2 of 24
APPLICATIONS
Electric power steering
Electric vehicles
Integrated starter generator/alternator
Encoder emulation
Automotive motion sensing and control
PRODUCT HIGHLIGHTS
Complete Resolver-to-Digital Interface: The AD2S1200
provides the complete solution for digitizing resolver
signals (12-bit resolution) with on-board programmable
sinusoidal oscillator.
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.
Triple Format Position Data: Absolute 12-bit angular
binary position data accessed either via a 12-bit parallel
port or via a 3-wire serial interface. Incremental encoder
emulation in standard A QUAD B format, with direction
output is available.
Digital Velocity Output: 12-bit signed digital velocity,
twos complement format, accessed either via a 12-bit
parallel port or via a 3-wire serial interface.
Programmable Excitation Frequency: Excitation fre-
quency easily programmable to 10 kHz, 12 kHz, 15 kHz, or
20 kHz by using the frequency select pins.
System Fault Detection: A fault detection circuit will
detect any loss of resolver signals, out of range input
signals, input signal mismatch, or loss of position tracking.
AD2S1200
Rev. 0 | Page 3 of 24
TABLE OF CONTENTS
AD2S1200Specifications ................................................................4
Absolute Maximum Ratings ............................................................6
ESD Caution ..................................................................................6
Pin Configuration and Function Descriptions .............................7
Resolver Format Signals ...................................................................8
Principle of Operation......................................................................9
Fault Detection Circuit.................................................................9
Connecting the Converter .........................................................11
Absolute Position and Velocity Output ....................................12
Parallel Interface..........................................................................12
Serial Interface.............................................................................14
Incremental Encoder Outputs...................................................16
On-Board Programmable Sinusoidal Oscillator.....................16
Supply Sequencing and Reset....................................................17
Charge Pump Output .................................................................17
Circuit Dynamics ............................................................................18
AD2S1200 Loop Response Model ............................................18
Sources of Error ..........................................................................19
Clock Requirements ...................................................................20
Connecting to the DSP...............................................................20
Outline Dimensions........................................................................21
Ordering Guide ...........................................................................21
REVISION HISTORY
Revision 0: Initial Version
AD2S1200
Rev. 0 | Page 4 of 24
AD2S1200SPECIFICATIONS
Table 1. (AV
DD
= DV
DD
= 5.0 V 5% @ -40C to +125C CLKIN 8.192 MHz, unless otherwise noted.)
Parameter
Min
Typ
Max
Unit
Conditions/Comments
Sin, Cos INPUTS
1
Voltage
3.24
3.6
3.96
V p-p
Sinusoidal waveforms, differential inputs
Input Bias Current
2
A
V
IN
= 3.96 V p-p
Input Impedance
1.0
M
V
IN
= 3.96 V p-p
Common Mode Volts
100
mV Peak
CMV @ SinLO, CosLO, with respect to REFOUT @ 10 kHz
Phase Lock Range
-45
+45
Degrees
Sin/Cos vs. EXC output
ANGULAR ACCURACY
Angular Accuracy
11
arc min
Zero acceleration Y Grade
22
arc min
Zero acceleration W Grade
Resolution
12
Bits
Guaranteed no missing codes
Linearity INL
2
LSB
Zero acceleration, 0 to 1,000 rps
Linearity DNL
0.3
LSB
Guaranteed monotonic
Repeatability
1
LSB
Hysteresis
1
LSB
VELOCITY OUTPUT
Velocity Accuracy
2
LSB
Zero acceleration
Resolution
11
Bits
Linearity
1
LSB
Guaranteed by design 2 LSB max
Offset
0
1
LSB
Zero acceleration
Dynamic Ripple
1
LSB
Zero acceleration
DYNAMIC PERFORMANCE
Bandwidth
1,500
1,700
2,000
Hz
Fixed
Tracking Rate
1,000
rps
Guaranteed by design. Tested to 800 rps.
Acceleration Error
30
arc min
At 10,000 rps
2
Settling Time 179 Step Input
4.72
5.0
ms
To within stated accuracy
Settling Time 179 Step Input
3.7
3.8
ms
To within one degree
EXC, EXC OUTPUTS
Voltage
3.34
3.6
3.83
V p-p
Load 100 A
Center Voltage
2.39
2.47
2.52
V
Frequency
10
kHz
FS1 = high, FS2 = high
12
kHz
FS1 = high, FS2 = low
15
kHz
FS1 = low, FS2 = high
20
kHz
FS1 = low, FS2 = low
EXC/EXC DC Mismatch
35
mV
THD
-60
-55
dB
First five harmonics
FAULT DETECTION BLOCK
LOS
Sin/Cos Threshold
2.86
2.92
3.0
V p-p
DOS and LOT go low when Sin or Cos fall below
threshold.
Angular Accuracy (Worst Case)
45
Degrees
LOS indicated before angular output error exceeds limit
(3.96 V p-p input signal and 2.9 V LOS threshold).
Angular Latency (Worst Case)
90
Degrees
Maximum electrical rotation before LOS is indicated
(3.96 V p-p input signal and 2.9 V LOS threshold).
Time Latency
125
s
1
The voltages Sin, SinLO, Cos, and CosLO relative to AGND must always be between 0.2 V and AV
DD
.
AD2S1200
Rev. 0 | Page 5 of 24
Parameter
Min
Typ
Max
Unit
Conditions/Comments
FAULT DETECTION BLOCK (CONT.)
DOS
Sin/Cos Threshold
4.0
4.09
4.2
V p-p
DOS goes low when Sin or Cos exceeds threshold.
Sin/Cos Mismatch
385
420
mV
DOS latched low when Sin/Cos amplitude mismatch
exceeds the threshold.
Angular Accuracy (Worst Case)
30
Degrees
DOS indicated before angular output error exceeds
limit.
Angular Latency (Worst Case)
60
Degrees
Maximum electrical rotation before DOS is indicated.
Time Latency
125
s
LOT
Tracking Threshold
5
Degrees
LOT goes low when internal error signal exceeds
threshold. Guaranteed by design.
Time Latency
1.1
ms
Hysteresis
4
Degrees
Guaranteed by design
VOLTAGE REFERENCE
REFOUT
2.39
2.47
2.52
V
IOUT = 100 A
Drift
70
ppm/C
PSRR
-60
dB
CHARGE PUMP OUTPUT (CPO)
Frequency
204.8
kHz
Square wave output
Duty Cycle
50
%
POWER SUPPLY
I
DD
Dynamic
18
mA
ELECTRICAL CHARACTERISTICS
V
IL
Voltage Input Low
0.8
V
V
IH
Voltage Input High
2.0
V
V
OL
Voltage Output Low
0.4
V
2 mA load
V
OH
Voltage Output High
4.0
V
-1 mA load
I
IL
Low Level Input Current
10
A
I
IH
High Level Input Current
-10
A
I
OZH
High Level Three-State Leakage
-10
A
I
OZL
Low Level Three-State Leakage
10
A
Document Outline
PDF 
ZIP