AEDR-850x
3 Channel Re ective Incremental Encoders
Data Sheet
Description
The AEDR-850X encoder is the smallest 3 channels optical
encoder with digital outputs in the market employing
re ective technology for motion control purposes. The
encoder is designed to operate over -20° C to 85° C tem-
perature range and hence suitable for both commercial
and even industrial end applications.
The encoder houses an LED light source and a photo-
detecting circuitry in a single package. The small size of
3.95 mm (L) x 3.4 mm (W) x 0.9562 mm (H), allows it to be
even used in a wide range of miniature commercial appli-
cation where size and space is a primary concern.
The AEDR-850X encoder o ers two-channel quadrature
digital outputs and a 3rd channel, index digital outputs.
Being TTL compatible, the outputs of the AEDR-850X
encoder can be interfaced directly with most of the signal
processing circuitries. Hence the encoder provides great
design-in  exibility and easy integration into existing
systems.
Features
 World smallest 3 channels re ective technology
encoder.
 Surface mount leadless package 3.95 mm (L) x 3.4 mm
(W) x 0.9562 mm (H)
 3 channels; two channel quadrature digital outputs
for direction sensing and a 3rd channel, Index digital
output.
 Build in interpolator, factor of 1x, 2x and 4x selectable
via external pinouts
TTL compatible
Single 5 V supply
-20° C to 85° C absolute operating temperature
Encoding resolution: 294 to 304 (lines/inch)
Applications
Ideal for high volume applications:
 Close Loop stepper Motors
 Miniature Motors
 Printers
 Copiers
 Card readers
 Scanners
 Projectors
 Consumer and Industrial Product Applications
Note: Drawing not to scale.
Codewheel
Reective Encoder
VCC
VCC
Ch A
Ch B
Ch I
SEL 4X
SEL 2X
Gnd
Gnd
Signal
Processing
Circuitry
R
Note: Avago Technologies encoders are not recommended for use in safety critical applications, e.g., ABS braking
systems, power steering, life support systems and critical care medical equipment. Avago’s products and software are
not speci cally designed, manufactured or authorized for sale as parts, components or assemblies for the planning, con-
struction, maintenance or direct operation of a nuclear facility or for use in medical devices or applications. Customers
are solely responsible, and waive all rights to make claims against Avago or its suppliers, for all losses, damage, expense
or liability in connection with such use. Please contact your local sales representative if more clari cation is needed.
2
Output waveform
Absolute Maximum Ratings
Storage Temperature, TS-20° C to 85° C
Operating Temperature, TA-20° C to 85° C
Supply Voltage, VCC 7 V
Output Voltage, VOVCC
Notes:
1. Exposure to extreme light intensity (such as from  ashbulbs 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 degradation induced by ESD.
3. Proper operation of the encoder cannot be guaranteed if the maximum ratings are exceeded.
Recommended Operating Conditions ( based on limited prototype samples testing @ 11.38 Rop codewheel)
Parameter Sym. Min. Typ. Max. Units Notes
Temperature TA-20 25 85 °C
Supply Voltage VCC 4.5 5 5.5 V Ripple < 100mVp-p
LED Current ILED 15mA mA See note 1
Count Frequency2F 55 kHz 1 x Interpolation Factor
Radial Misalignment ER±0.2 mm
Tangential Misalignment ET±0.2 mm
Codewheel Gap G 0.5 1.0 1.25 mm See note 3
Notes:
1. LED Current Limiting Resistor: Recommended series resistor = 180 (±1%)
2. Count frequency = velocity (rpm) x CPR / 60.
3. Avago recommends 1.0mm gap as nominal.
IIndex of 360 e Deg option
Po
C
360 e Deg
A
φ
BS1 S2 S3 S4
IIndex of 90 e Deg option
IIndex of 180 e Deg option
Codewheel rotation movement (Anti-clockwise)
QUADRATURE SIGNALS A, B and I
Po
P
Amplitude
Po
Codewheel
Encoder
Note: Drawing not to scale.
Anti-clockwise
Ch. A leads
Ch. B
Top View
3
Encoder Pin-Out
Pin con guration (Top view)
Encoder’s Built-in Interpolation
Pin (Interpolation) Interpolation
Factor
CPR @
( ROP = 11.38 mm )
Count
Frequency
SEL 4X SEL 2X
L L 1X 828 55 KHz
L H 2X 1656 110 KHz
H L 4X 3312 220 KHz
H H Factory use
H = HIGH Logic Level L = LOW Logic Level
The interpolation factor above may be used in conjunction with the below formulae to cater the needs for various
rotation speed (RPM) and count.
RPM = (Count Frequency x 60 ) / CPR
The CPR (@ 1X interpolation) is based on the following formulae which is directly dependent on ROP
CPR = LPI x 2 x ROP (inch) or
CPR = LPmm x 2 x ROP (mm)
Pin 8
Gnd
Pin 1
VLED
Pin 5
A
Pin 4
B
Emitter
Detector
Pin 6
VCC
Pin 7
SEL 4X
Pin 3
CHI
Pin 2
SEL 2X
4
Encoding Characteristics (Codewheel of Rop @11.38 mm)
Encoding characteristics over the recommended operating condition and mounting conditions.
Parameter Symbol Typical Unit
Interpolation factor 1 X 2 X 4 X
Cycle Error C18 22 36 °e
Pulse Width Error P15 20 30 °e
Phase Error  91518
°e
State Error S10 15 25 °e
Index Pulse Width (Gated 90°) PO90 90 90 °e
Index Pulse Width (Gated 180°) PO180 180 180 °e
Index Pulse Width (Gated 360°) PONot Available 360 360 °e
Notes:
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.
2. For optimal performance, please refer to alignment method as described in Application Note 5500 (document AV02-2789EN)
Electrical Characteristics
Characteristics over recommended operating conditions at 25° C.
Parameter Symbol Min. Typ. Max. Unit Notes
High Level Output Voltage VOH 2.4 V IOH = -1.5 mA
Low Level Output Voltage VOL 0.4 VIOH = +1.5 mA
Output current per channel, Iout IO- - 1.5 mA
Rise Time tr<100 ns CL = 25pF
RL = 2.7kΩ
Fall Time tf<100 ns
LED Current Limiting Resistor
A resistor to limit the current to the LED is required. The
recommended value is 180 (±1%) and the resistor
should be placed in series between the 5 V supply and pin
VLED of the encoder. This will result in an LED current of
approximately 15 mA for optimal encoder performance.
Gnd VLED
AB
Emitter
Detector
VCC
SEL 4X
CHI
SEL 2X
VCC
R
5
Codewheel Design Example
The following example demonstrates a codewheel design for a Rop of 11.38 mm @ 828 CPR for a typical 2 channels
encoder. In the case for an index track design, special index tracks have to be utilized.
Codewheel pattern for a 2 channels encoder Codewheel pattern for a 3 channels encoder
Notes:
a). 2 tracks from the original 828 CPR, 2 channels codewheel design have been utilized for the special track(Index), but CPR remains the same.
Codewheel Characteristics
The most important dimension to remember is that the index (I) channel pattern on the codewheel, the width angle is
made up of 3 x WB° (opaque-non re ective region).
Caution: As the Index track is generated by utilizing the 3xWB (opaque – non re ective)
region, any dirt that blocked the tracks resulting in the encoder’s detector sensing
a 3x WB will result in another erroneous Index.
LW = 1.8 mm (minimum)
Index track width angle is made up of 3 x W B°
828 CPR 0.43478°
0.21739°
Opaque (Cu)
Reflective (Ni)
828 CPR
0.21739°
826 X 0.43478°
0.652174°
Opaque (Cu)
Reflective (Ni)
Special track
3 x WB°
Opaque (Cu)
Reflective (Ni)
WB°
WW°
Lw
Index
track
6
Recommended Codewheel Characteristics
Parameter Symbol Min. Max. Unit Notes
Window/bar Ratio Ww/Wb 0.9 1.1
Window/bar Length LW1.80
(0.071)
–mm
(inches)
Specular Re ectance Rf60 – Re ective area. See note 1.
– 10 Non re ective area
Line Density LPmm 11.575 11.969 lines/mm
LPI 294 304 lines/inch Recommended LPI is 294
Notes:
1. Measurements from TMA Scan meter.
2. LPmm = CPR / [2.Rop(mm)]
3. The LED used in AEDR-850x has a typical peak wavelength of 630nm.
Outline Drawing
* All dimensions in millimeter.
Tolerance x.xx ± 0.15 mm
0.956
0.7662 ±0.0500
0.19 ±0.03
TOP VIEW
FRONT VIEW
Center of lens
3.40
3.95
2.62
BACK VIEW
8 X Ø 0.30
8 X 0.450
2 X 0.950
2 X 0.950
8 X 0.350
2 X 0.900 2 X 0.900
0.50
2.15
NC
7
Encoder Placement Orientation and Positioning
The AEDR-850X is designed such that both the emitter and detector IC should be placed parallel to the window/bar
orientation, as shown (with the encoder mounted on top of the codewheel. See view below).
Most importantly, the center of the lens of the encoder unit; needs to be in line with the operating radius of the codewheel
(ROP) or rather the center point of Lw (0.5 of the Length of Window). Lw is recommended to be 1.8 mm or greater.
Top View
Codewheel
Placement orientation of
the encoder’s on the codewheel
Note: Drawing not to scale
Emitter
Detector
Codewheel
Direction of Movement
With the detector side of the encoder placed closer to the codewheel centre, see the above top view; Channel A leads Channel
B when the codewheel rotates anti-clockwise and vice versa (with the encoder mounted on top of the codewheel).
The optimal gap setting recommended is between 0.5 to 1.25 mm (See side view below).
Side View
Gap = 0.5 to 1.25 mm
(1.0mm nominal)
Encoder height = 0.9562 mm
Codewheel
Note: Drawing not to scale.
Anti-clockwise
Ch. A leads
Ch. B
Ch. B leads
Ch. A
Emitter
Codewheel
Clockwise
Emitter
Codewheel
Top
View
8
Recommended Land Pattern for AEDR-850X
3.40
Package outline
0.80
1.45
0.35
3.95
2.45
Front View
Moisture Sensitivity Level
The AEDR-850X is speci ed to moisture sensitive level (MSL) 3. Precaution is required to handle this moisture sensitive
product to ensure the reliability of the product.
Storage before use
- Un-open moisture barrier bag (MBB) can be stored at <40’C/90%RH for 12 months.
- It is not recommended to open the MBB prior to assembly.
Control after open the MBB
- Encoder that will be subjected to re ow solder must mounted within 168hrs of factory condition <30’C/60%RH
Control for un nished reel
- Stored and sealed MBB with desiccant or desiccators at <5%RH.
Baking is required if :
- Humidity indicator card (HIC) is >10% when read at 23±5°C
- The encoder  oor life exceeded 168 hours.
- Recommended baking condition : 60±5°C for 20 hours (tape and reel)
125 ±5°C for 5 hours (loose unit)
9
Recommended Lead-free Re ow Soldering Temperature Pro le
Average ramp up rate = 3°C/sec
Average ramp down rate = 6°C/sec
Preheat temperature = 150° C to 200° C
Preheat time = 60 to 100 sec
Time maintain above 217° C = 40 to 60 sec
Peak Temperature = 235° C
Time within 5° C of peak temperature = 20 to 30 sec
Note:
1. Re ow with peak temperature > 235° C may cause damage to the component.
2. Due to treatment of high temperature, this clear compound may turn yellow
after IR re ow.
3. Pro le shown here is the actual readings from the thermocouple (attached
to AEDR-850x as shown to the right) on the re ow board PCB.
0
50
100
150
200
250
0 25506075100 125 150 175 200 225 250 275 300 324 354
Preheat Zone
Liquidus point 217 °C
60 sec Max
Max 235 °C
Tape and reel information
Mold
Compound
IC
Reow PCB
Thermocouple
LED
For product information and a complete list of distributors, please go to our web site: www.avagotech.com
Avago, Avago Technologies, and the A logo are trademarks of Avago Technologies in the United States and other countries.
Data subject to change. Copyright © 2005-2012 Avago Technologies. All rights reserved.
AV02-2790EN - June 27, 2012
Ordering Information
Index Gating
AEDR – 850x – x0x
0 – Gated 90º e
1 – Gated 180º e
2 – Gated 360º e
Shipping Units
0 – 1000 pcs
2 – 100 pcs
Packaging
1 – Tape and Reel
Note: Avago Technologies encoders are not recommended for use in safety critical applications, e.g., ABS braking
systems, power steering, life support systems and critical care medical equipment. Avago’s products and software are
not speci cally designed, manufactured or authorized for sale as parts, components or assemblies for the planning, con-
struction, maintenance or direct operation of a nuclear facility or for use in medical devices or applications. Customers
are solely responsible, and waive all rights to make claims against Avago or its suppliers, for all losses, damage, expense
or liability in connection with such use. Please contact your local sales representative if more clari cation is needed.