Features
Reflective technology
Surface mount small outline leadless package
Direct replacement of HEDR-8000 encoder
Single channel incremental output
Two channels quadrature outputs for direction
sensing
Single 5 V supply, TTL compatible output
-20°C to 85°C absolute operating temperature
Lead-free package
Encoding resolution options:
75, 150 and 180 (lines/inch) or 2.95, 5.91, 7.09
(lines/mm)
PCB height profile options:
1.0 mm PCB thickness 1.5 mm PCB thickness
Description
By introducing an additional PCB top-up thickness at-
tached to the encoder, the AEDR-8000 Encoder series
could easily solve the height issue in various applica-
tions. Furthermore, this great feature is enhanced with
the offering of different height profile options.
Direct Replacement of HEDR-8000 Encoder series is now
possible with the AEDR-8000 Encoder series. Such migra-
tion is always simple and easy due to the perfect match-
ing of the height profiles as well as same footprints in
both encoder series.
The AEDR-8000 Encoder series employs reflective tech-
nology for rotary and linear movement control. The en-
coder houses an LED light source and a photo-detecting
circuitry in a single package.
In adding on to the main features, The AEDR-8000 En-
coder series offers two-channel quadrature digital out-
puts (TTL compatible) where signal could be interfaced
directly with most of the signal processing circuitries.
Thus, it’s bound to reduce the design time of an applica-
tion.
Applications
The AEDR-8000 Encoder series provides motion sensing
at a competitive price, making it ideal for high volume
applications. Its small size and surface mount package
make it ideal for printers, copiers, card readers and many
consumer products, particularly where space and weight
are design constraints.
Note: All specifications are subject to change without prior notification.
AEDR-8000 Series
Reflective Surface Mount Optical Encoder
Data Sheet
2
Block Diagram of AEDR-8000 Encoder
Phase Error (Df): The deviation of phase, in electrical de-
grees, from its ideal value of 90°e.
Pulse Width (P): The duration of high state of the output,
in electrical degrees, within one cycle. Nominally 180°e
or half a cycle.
Pulse Width Error (DP): The deviation of pulse width, in
electrical degrees, from its ideal value of 180°e.
Count (N): The number of window and bar pairs per revo-
lution (CPR) of codewheel. For linear codestrip, defined
as the number of window and bar pairs per unit length
(lines per inch [LPI] or lines per mm [LPmm]).
One Cycle (C): 360 electrical degrees (°e). Equivalent to
one window and bar pair.
One Shaft Rotation: 360 mechanical degrees. Also equiv-
alent to N counts (codewheel only).
Line Density: The number of window and bar pairs 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 the surface of the encoder to
the surface of codewheel or codestrip.
Specular Reflectance (Rf): 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 fac-
tory for more information).
Radial and Tangential Misalignment Error (ER, ET): For ro-
tary motion, mechanical displacement in the radial and
tangential directions relative to the nominal alignment.
Angular Misalignment Error (EA): Angular displacement
of the encoder relative to the tangential line.
Theory of Operation
The AEDR 8000 Encoder series combines an emitter and
a detector in a single surface mount leadless package.
When used with a codewheel or linear codestrip, the en-
coder translates rotary or linear motion into digital out-
puts. As seen in the block diagram, the AEDR-8000 En-
coder series consists of three major components: a light
emitting diode (LED) light source, a detector IC consist-
ing 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 absence
and presence of light. In this case, the rotary/linear mo-
tion of an object being monitored is converted to equiv-
alent light pattern via the use of codewheel/codestrip.
As shown in the above diagram, the reflective area (win-
dow) 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 pattern, corresponding to the window and bar, falls
on the photodiodes as the codewheel rotates. The mov-
ing light pattern is exploited by the detector circuitry to
produce digital outputs representing the rotation of the
codewheel. When the codewheel is coupled to a motor,
the encoder outputs are 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°e.
State Width Error (DS): The deviation of state width, in
electrical degrees, from its ideal value of 90°e.
Phase (f): 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°e.
SIGNAL
PROCESSING
CIRCUITRY
V
CC
CH A
V
LED
GND
CH B
GND
RCODEWHEEL
or
CODESTRIP
3
Output Waveform
CH. A
ALL FOUR STATES (S1 to S4)
ARE MAINTAINED.
CH. B
S1
P
C
S2 S3
CODEWHEEL ROTATION OR LINEAR MOVEMENT
AMPLITUDE
S4 φ
SHAFT
RADIAL (ER)
TANGENTIAL (ET)
AEDR-8000
CODEWHEEL
SHAFT
ANGULAR (EA)
AEDR-8000
CODEWHEEL
Absolute Maximum Ratings
Storage Temperature, TS -40°C to 85°C
Operating Temperature, TA -20°C to 85°C
Supply Voltage, VCC -0.5 V to 7 V
Output Voltage, VO -0.5 V to VCC
Output Current per Channel, IOUT -1.0 mA to 8 mA
ESD 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.
4
Recommended Operating Conditions
Parameter Sym. Min. Typ. Max. Units Notes
Temperature TA 0 25 85 °C
Supply Voltage VCC 4.5 5.0 5.5 V Ripple < 100 mVp-p
LED Current ILED 13 15 18 mA See note 1
Load Capacitance CL 100 pF 2.7 kΩ Pull-Up
Count Frequency f 30 kHz See note 2
Radial Misalignment ER ±0.38 mm (in.)
(±0.015)
Tangential Misalignment ET ± 0.38 mm (in.)
(± 0.015)
Angular Misalignment EA 0 ± 1.5 deg.
Codewheel/Strip Tilt CT 0 1 deg.
Codewheel/Strip Gap G 1.0 (0.04) 2.0 (0.08) 2.5 (0.10) mm (in.)
Note:
1. Refer to “LED Current Limiting Resistor” on page 5.
2. Count frequency = velocity (RPM) x N/60.
Encoding Characteristics
Encoding characteristics over the recommended operating condition and mounting conditions.
Parameter Symbol Typical Maximum Unit Notes
Pulse Width Error DP 15 55 °e AEDR-8010-K
Pulse Width Error (Ch. A, Ch. B) DP 15, 25 55, 75 °e AEDR-8000-K
16 75 AEDR-8100-P
16 75 AEDR-8100-Q
Phase Error Df 12 60 °e AEDR-8000-K
10 60 AEDR-8100-P
10 60 AEDR-8100-Q
Note: 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.
Electrical Characteristics
Characteristics over recommended operating conditions at 25°C.
Parameter Symbol Min. Typ. Max. Unit Notes
Detector Supply Current Icc 2.2 5.0 mA
High Level Output Voltage VOH 2.4 V IOH = -0.2 mA
Low Level Output Voltage VOL 0.4 V IOL = 8.0 mA
Rise Time tr 500 ns CL = 25 pF
Fall Time tf 100 ns RL = 2.7 kΩ
5
Recommended Codewheel and Codestrip Characteristics
Parameter Symbol Min. Max. Unit Notes
Window/Bar Ratio Ww/Wb 0.9 1.1
Window/Bar Length LW 1.80 (0.071) 2.31 (0.091) mm (inches)
Specular Reflectance Rf 60 85 Reflective area. See note 1.
10 Nonreflective area
2.95 (75) AEDR-80X0-K
5.91 (150) AEDR-8100-P
7.09 (180) AEDR-8100-Q
Optical Radius Rop 11 mm Recommended value
Notes:
1. Measurements from TMA µScan meter. Contact factory for more information.
2. Contact factory for more information on compatibility of codewheel/strip.
LED Current Limiting Resistor
A resistor to limit current to the LED is required. The
recommended value is 220 Ω (±10 %) and the resistor
should be placed in series between the 5 V supply and
pin 3 of the device (Vled). This will result in an LED current
of approximately 15 mA.
Moisture Sensitive Level
The AEDR-8000 series is specified to moisture sensitive
level (MSL) 3.
WbWw
WwWb
Lw
Rop Lw
6
Package Outline Drawing
2.7
1.5
SIDE VIEW (LOW RESOLUTION) SIDE VIEW (HIGH RESOLUTION)
1.65
0.38
0.59
1.30
0.78
4.38
6.23
1.02
0.7
0.4
1.04
7
Encoder Orientation
The AEDR-8000 series is designed such that both the LED
and detector IC should be placed parallel to the window/
bar orientation, as shown. As such, the encoder is toler-
ant against radial play of ± 0.38 mm. The emitter side
should be placed closer to the rotating shaft.
Mounting Consideration
Direction of Codewheel Rotation
With the emitter side of the encoder placed closer to the
codewheel centre, Channel A leads Channel B when the
codewheel rotates anti-clockwise and vice versa.
Viewed from Top
CODESTRIP
DIRECTION OF
RADIAL PLAY
CODEWHEEL
DIRECTION OF
RADIAL PLAY
CH. A LEADS
CH. B
EMITTER
ANTI-CLOCKWISE
CH. B LEADS
CH. A
EMITTER
CLOCKWISE
ROP
11.00 mm (0.433 IN) < ROP <
CODEWHEEL/CODESTRIP
GAP
8
Recommended Lead-Free Reflow Soldering Temperature Profile
Preheat Temperature 40°C to 125°C = 120 sec. max.
Temperature Maintain Above 217°C = 60 – 150 sec.
Peak Temperature = 255 ± 5°C
Time Above 250°C = 10 – 20 sec.
Note: Due to treatment of high temperature, AEDR-8000 transparent compound is expected to turn yellow after IR reflow.
Resolution Indicator
Since the encoder is too small to imprint resolution
marking on its package, color-coding the package is em-
ployed to differentiate resolutions. The details are:
LPI 75 150 180
Color Clear Red Amber
300
250
200
150
100
50
01 22 45 66 87 108 129 150 171 192 213 235 256 278 299 320 341 363 384
255C
250C
217C
40C
125C
10 - 20 SEC.
120 SEC. MAX. 60 - 150 SEC.
TIME (SEC.)
HEAT UP SOLDER PASTE DRY SOLDER REFLOW COOL DOWN
TEMPERATURE (C)
Ordering Information
AEDR-8 0 Option
PCB Thickness Number of Packaging Lines per Inch Shipping Units
0 - 1.5 mm (Low Channels 1 - Tape and K - 75 LPI 0 - 1000 pcs
Resolution) 1 - One Channel Reel P - 150 LPI 1 - 500 pcs
1 - 1.0 mm (High 0 - Two Channels Q - 180 LPI 2 - 100 pcs
Resolution)
Note: Encoders are packed in tape of quantity 1000 pcs or 500 pcs or 100 pcs.
Available Options
Resolution Shipping Units
K – P – Q – 0 – 1 – 2 –
Encoder 75 LPI 150 LPI 180 LPI 1000 pcs 500 pcs 100 pcs
AEDR-8000 * * * *
AEDR-8010 * *
AEDR-8100 * * * *
AEDR-8100 * * *
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Data subject to change. Copyright © 2005-2009 Avago Technologies. All rights reserved. Obsoletes 5989-3067EN
AV02-0971EN - August 27, 2009