AEDR-8300 Series Encoders
Reflective Surface Mount Optical Encoder
Data Sheet
Description
The AEDR-8300 series is the smallest optical encoder
employing reflective technology for motion control
purposes. The encoder houses an LED light source and
a photo-detecting circuitry in a single package.
The AEDS-8300 series offers options of either single
channel or two-channel quadrature digital outputs.
Being TTL compatible, the outputs of the AEDR-8300
series can be interfaced directly with most of the signal
processing circuitries. Hence the encoder provides great
design-in flexibility and easy integration into existing
systems. The AEDR-8300 series is available in four reso-
lutions, namely 36, 75, 150 and 180 lines per inch (LPI)
(1.42, 2.95, 5.91 and 7.09 lines per mm respectively).
This range of resolutions caters for different design and
application needs.
Features
•
Reflective technology
•
Surface mount small outline leadless package
•
Single channel incremental output
•
Two channel quadrature outputs for direction sens-
ing
•
TTL compatible output
•
Single 5V supply
•
-20
o
C to 85
o
C absolute operating temperature
•
Encoding resolution options:
36, 75, 150, 180 (lines/inch) or 1.42, 2.95, 5.91, 7.09
(lines/mm)
Applications
The AEDR-8300 series provides motion sensing at a
competitive cost, making it ideal for high volume appli-
cations. Its small size and surface mount package make
it ideal for printers, copiers, card readers and many con-
sumer products, particularly where space and weigh are
design constraint.
Note: All specifications are subject to change without prior notification.
Theory of Operation
The AEDR-8300 series combines an emitter and a detec-
tor in a single surface mount leadless package. When
used with a codewheel or linear codestrip, the encoder
translates rotary or linear motion into digital outputs.
As seen in the block diagram, the AEDR-8300 consists
of three major components: a light emitting diode (LED)
light source, a detector IC consisting photodiodes and
lens to focus light beam from the emitter as well as light
falling on the detector.
The operation of the encoder is based on the principle
of optics where the detector photodiodes sense the ab-
sence and presence of light. In this case, the rotary/lin-
ear motion of an object being monitored is converted
to equivalent light pattern via the use of codewheel/
codestrip. As shown in the diagram below, the reflective
area (window) of the codewheel (or codestrip) reflects
light back to the photodetector IC, whereas no light is
reflected by the non-reflective area (bar). An alternating
light and dark patterns corresponding to the window
and bar fall on the photodiodes as the codewheel ro-
tates. The moving light pattern is exploited by the de-
tector circuitry to produce digital outputs representing
the rotation of the codewheel. When the codewheel is
coupled to a motor, the encoder outputs is then a direct
representation of the motor rotation. The same concept
applies to the use of a codestrip to detect linear motion.
Definitions
State Width (S):
The number of electrical degrees be-
tween a transition in Channel A and the neighboring
transition in Channel B. There are 4 states per cycle,
each nominally 90
o
e.
State Width Error (∆S):
The deviation of state width, in
electrical degree, from its ideal value of 90
o
e.
Phase (φ):
The number of electrical degrees between
the center of high state of Channel A and the center of
high state of Channel B. Nominally 90
o
e.
Phase Error (∆φ):
The deviation of phase, in electrical
degree, from its ideal value of 90
o
e.
Pulse Width (P):
The duration of high state of the out-
put, in electrical degree, within one cycle. Nominally
180
o
e or half a cycle.
Pulse Width Error (∆P):
The deviation of pulse width, in
electrical degree, from its ideal value of 180
o
e.
Count (N):
The number of window and bar pair per rev-
olution (CPR) of codewheel. For linear codestrip, defined
as the number of window and bar pair per unit length
(lines per inch [LPI] or lines per mm [LPmm]).
One Cycle (C):
360 electrical degrees (
o
e). Equivalent to
one window and bar pair.
V
LED
GND
V
CC
CH A
CH B
R
CODEWHEEL
OR
CODESTRIP
SIGNAL
PROCESSING
CIRCUITRY
GND
Figure 1. Block Diagram of AEDR-8300.
AEDR-8300 block diag
2
One Shaft Rotation:
360 mechanical degrees. Also
equivalent to N counts (codewheel only).
Line Density:
The number of window and bar pair per
unit length, expressed in either lines per inch (LPI) or
lines per mm (LPmm).
Optical radius (Rop):
The distance between the code-
wheel center and the centerline between the two
domes of the encoder.
Gap (G):
The distance from surface of the encoder to
the surface of codewheel or codestrip.
Specular Reflectance (R
f
):
The amount of incident light
reflected by a surface. Quantified in terms of the per-
centage of incident light. A spectrometer can be used
to measure specular reflectance of a surface (contact
factory for more information).
Radial and Tangential Misalignment Error (E
R
, E
T
):
For
rotary motion, mechanical displacement in the radial
and tangential directions relative to the nominal align-
ment.
Angular Misalignment Error (E
A
):
Angular displace-
ment of the encoder relative to the tangential line.
C
P
ALL FOUR STATES (S1 TO S4)
ARE MAINTAINED.
CH. A
AMPLITUDE
S1
S2
S3
S4
φ
CH. B
CODEWHEEL ROTATION OR LINEAR MOVEMENT
RADIAL (E
R
)
AEDR-8300 output wave.
TANGENTIAL (E
T
)
ANGULAR (E
A
)
AEDR-8300
AEDR-8300
SHAFT
SHAFT
CODEWHEEL
CODEWHEEL
AEDR-8300 angular misalign.
3
AEDR-8300 Absolute Maximum Ratings
Storage Temperature, T
S
Operating Temperature, T
A
Supply Voltage, V
CC
Output Voltage, V
O
Output Current per Channel, I
OUT
ESD
-40°C to 85°C
-20°C to 85°C
-0.5 V to 7 V
-0.5 V to V
CC
-1.0 mA to 8 mA
Human Body Model JESD22-A114-A Class 2
Machine Model JESD22-A115-A Class B
Notes:
1. Exposure to extreme light intensity (such as from flashbulbs or spotlights) may cause permanent damage to the device.
2. CAUTION: It is advised that normal static precautions should be taken when handling the encoder in order to avoid damage and/or degrada-
tion induced by ESD.
3. Proper operation of the encoder cannot be guaranteed if the maximum ratings are exceeded.
AEDR-8300 Recommended Operating Conditions
Parameter
Temperature
Supply Voltage
LED Current
Load Capacitance
Count Frequency
Count Frequency
Radial Misalignment
Tangential Misalignment
Angular Misalignment
Codewheel/strip tilt
Codewheel/strip Gap
f
E
R
E
T
E
A
C
T
G
1.0 (0.04)
0
0
2.0 (0.08)
Sym.
T
A
V
CC
I
LED
C
L
f
Min.
-20
4.5
13
Typ.
25
5
15
Max.
85
5.5
18
100
30
15
±0.38 (±0.015)
±0.38 (±0.015)
±1.5
1
2.5 (0.10)
Units
°C
V
mA
pF
kHz
kHz
mm (in.)
mm (in.)
deg.
deg.
mm (in.)
Ripple< 100mVp-p
See note 1
2.7 kW Pull-Up
AEDR-83X0-K/P/Q
See Note 2
AEDR-8310-V
Notes
Note:
1. Refer to “LED Current Limiting Resistor” in Page 6.
2. Count frequency = velocity(rpm)xN/60.
4
AEDR-8300 Encoding Characteristics
Encoding characteristics over the recommended operating condition and mounting conditions.
Parameter
Pulse Width Error
Pulse Width Error
(Ch.A, Ch. B)
Phase Error
Symbol
∆P
∆P
∆P
∆P
∆φ
∆φ
∆φ
Typical
15
16
15, 25
16
16
12
10
10
Maximum
55
75
55, 75
75
75
60
60
60
Units
°e
°e
°e
°e
°e
°e
°e
°e
Notes
AEDR-8310-K
AEDR-8310-V
AEDR-8300-K
AEDR-8300-P
AEDR-8300-Q
AEDR-8300-K
AEDR-8300-P
AEDR-8300-Q
Note:
1. Typical values represent the encoder performance at typical mounting alignment, whereas the maximum values represent the encoder
performance across the range of recommended mounting tolerance.
AEDR-8300 Electrical Characteristics
Characteristics over recommended operating conditions at 25°C.
Parameter
Detector Supply Current
High Level Output Voltage
Low Level Output Voltage
Rise Time
Fall Time
Sym.
I
CC
V
OH
V
OL
t
r
t
f
500
100
2.4
0.4
Min.
Typ.
2.2
Max.
5.0
Units
mA
V
V
ns
ns
I
OH
= –0.2 mA
I
OL
= 8.0 mA
C
L
= 25 pF, R
L
= 2.7 kW
C
L
= 25 pF, R
L
= 2.7 kW
Notes
AEDR-8300 Encoder Pin Configuration
Encoder option
AEDR-8310-K/V
AEDR-8300-K/P/Q
Pin 1
NC
Ch B
Pin 2
Gnd
Gnd
Pin 3
V
LED
V
LED
Pin 4
Gnd
Gnd
Pin 5
Ch A
Ch A
Pin 6
V
cc
V
cc
5
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