AD2S81A/AD2S82A
1M⍀
100k⍀
22nF
15k⍀
100nF
4.7M⍀
REFERENCE
INPUT
VELOCITY
O/P
100nF
22nF
15k⍀
1.5nF
6.8nF
39k⍀
110k⍀
68⍀
180k⍀
COS HIGH
REF LOW
COS LOW
SIN LOW
RESOLVER
SIGNAL
470pF
100nF
6
7
5
4
3
2
1
44 43 42 41 40
–12V
39
38
37
36
35
34
33
32
31
SIN HIGH
+12V
PIN 1
IDENTIFIER
RIPPLE CLK
DIRECTION
BUSY
8
9
MSB
10
11
12
13
14
15
16
17
DATA LOAD
AD2S82A
TOP VIEW
(Not to scale)
COMPLEMENT
SC2
DATA
OUTPUT
0V
30 INHIBIT
29
18 19 20 21 22 23 24 25 26 27 28
LSB
BYTE SELECT
ENABLE
DATA OUTPUT
+5V
Figure 11. Typical Circuit Configuration
TYPICAL CIRCUIT CONFIGURATION
For more information on resistive scaling of SIN, COS and
REFERENCE converter inputs, refer to the application note
“Circuit Applications of the 2S81 and 2S80 Resolver-to-Digital
Converters.”
Figure 11 shows a typical circuit configuration for the AD2S81A/
AD2S82A in a 12-bit resolution mode. Values of the external
components have been chosen for a reference frequency of 5 kHz
and a maximum tracking rate of 260 rps with a bandwidth of
520 Hz. Placing the values for R4, R6, C4 and C5 in the equa-
tion for KA gives a value of 2.7 × 106. The resistors are 0.125 W,
5% tolerance preferred values. The capacitors are 100 V ceramic,
10% tolerance components.
APPLICATIONS
Control Transformer
The ratio multiplier of the AD2S82A can be used independently
of the loop integrators as a control transformer. In this mode the
resolver inputs θ are multiplied by a digital angle φ, any differ-
ence between and φ and θ will be represented by the AC ERROR
output as SIN ωt sin (θ–φ) or the DEMOD output as sin (θ–φ).
To use the AD2S81A/AD2S82A in this mode refer to the
“Control Transformer” application note.
For signal and reference voltages greater than 2 V rms a simple
voltage divider circuit of resistors can be used to generate the
correct signal level at the converter. Care should be taken to
ensure that the ratios of the resistors between the sine signal line
and ground and the cosine signal line and ground are the same.
Any difference will result in an additional position error.
Dynamic Switching
In applications where the user requires wide band response from
the converter, for example 100 rpm to 6000 rpm, superior per-
formance is achieved if the converters control characteristics are
switched dynamically. This reduces velocity offset levels at low
tracking rates. For more information on the technique refer to
“Dynamic Resolution Switching Using the Variable Resolution
Monolithic Resolver-to-Digital Converters.”
360
315
270
225
180
OTHER PRODUCTS
The AD2S80A is a monolithic resolver-to-digital converter
offering 10–16 bits of resolution and user selectable dynamics.
The AD2S80A is also available in 40-lead ceramic DIP, 44-lead
LCC and is qualified to MIL-STD 883B Rev C.
135
90
45
0
The AD2S46 is a highly integrated hybrid resolver/synchro to
digital converter packaged in a 28-lead ceramic DIP. The part
offers the user 1.3 arc minutes of accuracy over the full military
temperature range.
0
4
8
12
16
20
24
TIME – ms
Figure 12. Large Step Response Curves for Typical Circuit
Shown in Figure 11
The AD2S34 is a dual channel 14-bit hybrid resolver-to-digital
converter packaged in a 1 in2 32-lead flatpack.
The 1740/41/42 are hybrid resolver/synchro to digital converters
which incorporate pico-transformer isolated input signal
conditioning.
REV. B
–15–
ADI [ ADI ]
