AD2S81AJD Analog Devices Inc, AD2S81AJD Datasheet - Page 12

• Manufacturer Part Number: AD2S81AJD
• Description: IC R/D CONV TRACKING 28CDIP
• Manufacturer: Analog Devices Inc
• Type: R/D Converterr

Specifications of AD2S81AJD

• Rohs Status: RoHS non-compliant
• Input Type: Parallel
• Output Type: Digital
• Interface: Parallel
• Current - Supply: 30mA
• Mounting Type: Through Hole
• Package / Case: 28-CDIP (0.600", 15.24mm)
• Resolution (bits): 12bit
• Input Channel Type: Parallel
• Data Interface: Parallel
• Supply Voltage Range - Analog: ± 10.8V To ± 13.2V
• Supply Current: 19mA
• Digital Ic Case Style: DIP
• No. Of Pins: 40
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

AD2S80A
The small signal step response is shown in Figure 6. The time
from the step to the first peak is t
POSITION
OUTPUT
–135
–180
–12
180
135
–45
–90
0.02f
12
–3
–6
–9
0.02f
90
45
9
6
3
0
0
BW
BW
0.04f
0.04f
t
1
BW
BW
0.1f
0.1f
BW
BW
FREQUENCY
FREQUENCY
0.2f
0.2f
t
2
1
BW
BW
and the t
0.4f
0.4f
BW
BW
2
is the time from
f
f
BW
BW
2f
2f
BW
BW
TIME
the step until the converter is settled to 1 LSB. The times t
t
where R = resolution, i.e., 10, 12, 14, or 16.
The large signal step response (for steps greater than 5 degrees)
applies when the error voltage exceeds the linear range of the
converter.
Typically the converter will take 3 times longer to reach the first
peak for a 179 degrees step.
In response to a velocity step, the velocity output will exhibit the
same time response characteristics as outlined above for the
position output.
ACCELERATION ERROR
A tracking converter employing a Type 2 servo loop does not
suffer any velocity lag, however, there is an additional error due
to acceleration. This additional error can be defined using the
acceleration constant K
The numerator and denominator must have consistent angular
units. For example if K
may be specified in degrees/sec
Angular measurement may also be specified using radians, min-
utes of arc, LSBs, etc.
K
to it’s acceleration. The maximum acceleration allowable before
the converter loses track is dependent on the angular accuracy
requirements of the system.
K
given input acceleration. For example for an acceleration of
100 revs/sec
To determine the value of K
used to define the dynamics of the converter the following
should be used.
Where n = resolution of the converter.
2
A
A
are given approximately by
does not define maximum input acceleration, only the error due
can be used to predict the output position error for a
=
100 [rev/sec
Error in LSBs =
2.7×10
R4, R6 in ohms
C5, C4 in farads
2
, K
Angular Accuracy × K
A
K
= 2.7 × 10
2
K
] × 2
6
A
A
=
=
A
A
2
12
t
t
Error in Output Angle
1
is in sec
2
of the converter.
n
Input acceleration [LSB/sec
Input Acceleration
=
• R6• R4 •(C4 + C5)
= 0.15 LSBs or 47.5 seconds of arc
=
6
A
f
sec
4.04 ×10
f
based on the passive components
BW
1
BW
2
5
and the error output in degrees.
–2
–2
, then the input acceleration
and 12-bit resolution.
×
A
K
= Degrees/sec
12
A
R
[sec
11
–2
]
2
2
]
1
and