Agilent HEDR-8130
Reflective Optical Surface
Mount Encoders
Data Sheet
Features
• Reflective technology
• Surface mount S0-8 package
• Two channel quadrature outputs
for direction sensing
• 3.3 V input and output
• 150 lpi (5.91 lines/mm)
Description
The HEDR-8130 encoder uses
reflective technology to sense
rotary or linear position. This sen-
sor consists of an LED light source
and a photodetector IC in a single
S0-8 surface mount package. When
used with a reflective codewheel or
codestrip, this device can sense
rotary or linear position.
The reflective surface mount opti-
cal encoder provides two square
wave outputs in quadrature for
count and direction information.
These TTL-compatible outputs
correspond to the alternating re-
flective/non-reflective pattern of
the codewheel or codestrip.
The HEDR-8130 can be used with
a codewheel or codestrip with 150
lines per inch (5.91 lines per mm).
Applications
The HEDR-8130 provides two
channel motion sensing at a very
low cost, making it ideal for high
volume applications. Its small size
and surface mount capability make
it ideal for printers, copiers, card
readers, and consumer product
applications.
Theory of Operation
The HEDR-8130 combines an
emitter and a detector in a single
surface mount S0-8 package.
When used with a codewheel or
codestrip, the reflective sensors
translate rotary or linear motion
into a two-channel digital output.
The HEDR-8130 has three key
parts: a single Light Emitting
Diode (LED) light source, a
photodetector IC with a set of
uniquely configured photodiodes,
and a pair of lenses molded into
the package. The lens over the
LED focuses light onto the
codewheel or codestrip. Light is
either reflected or not reflected
back to the lens over the photo-
detector IC.
ESD WARNING: NORMAL HANDLING PRECAUTIONS SHOULD BE TAKEN TO AVOID STATIC DISCHARGE.
As the codewheel rotates, or
codestrip passes by, an alternat-
ing pattern of light and dark cor-
responding to the pattern of the
codewheel falls upon the photo-
diodes. This light is used to pro-
duce internal signals A and A-bar,
and B and B-bar. As part of this
“push-pull” detector system,
these signals are fed through
comparators to produce the final
output for channels A and B.
Note: Agilent Technologies
encoders are not recommended
for use in safety critical
applications. Eg. ABS braking
systems, power steering, life
support systems and critical care
medical equipment. Please
contact sales representative if
more clarification is needed.
2
Definitions
(Note: Refer to the Appendix for
Signals Diagram.)
Count (N) = The number of bar
and window pairs or Counts Per
Revolution (CPR) of the code-
wheel, or the number of Lines Per
Inch of the codestrip (LPI).
1 Shaft Rotation
= 360 mechanical degrees
= N cycles
1 cycles (c)
= 360 electrical degrees (˚e)
= 1 bar and window pair
Pulse Width (P): The number of
electrical degrees that an output
is high during one cycle. This
value is nominally 180˚e or 1/2
cycle.
Pulse Width Error (∆P): The
deviation, in electrical degrees, of
the pulse width from its ideal
value of 180˚e.
State Width (S): The number of
electrical degrees between a tran-
sition in the output of channel A
and the neighboring transition in
the output of channel B. There
are 4 states per cycle, each nomi-
nally 90˚e.
State Width Error (∆S): The
deviation, in electrical degrees, of
each state width from its ideal
value of 90˚e.
Phase (φ): The number of electri-
cal degrees between the center of
the high state of channel A and
the center of the high state of
channel B.
This value is nominally 90˚e for
quadrature output.
Phase Error (∆φ): the deviation
of the phase from its ideal value
of 90˚e.
Direction of Rotation: When
the codewheel or codestrip
moves in the direction from pin 1
to pin 4, as viewed when looking
down on the lenses, channel B
will lead channel A. If the
codewheel or codestrip moves in
the opposite direction, channel A
will lead channel B.
Optical Radius (Rop): For ro-
tary motion, the distance from
the codewheel’s center of rota-
tion to the center line connecting
the two lenses of the encoder.
Gap (G): The distance from the
top of the package to the surface
of the reflective codewheel or
codestrip.
Specular Reflectance (Rf): A
measure of a surface’s reflective
finish. This is quantified by the
amount of light reflected when hit
with an incident beam. A device
called a scatterometer is used to
quantify specular reflectance on a
percent scale. (Contact factory
for more information.)
Radial and Tangential Mis-
alignment Error ER, ET): For
rotary motion, mechanical mis-
alignment in the radial and tan-
gential directions relative to the
codewheel.
Angular Misalignment Error
(EA): Angular misalignment of
the sensor in relation to the tan-
gential direction. This applies for
both rotary and linear motion.
Absolute Maximum Ratings
Parameter Symbol Min. Max. Units Notes
Storage Temperature TS–40 85 ˚C
Operating Temperature TA–10 85 ˚C
Supply Voltage VCC –0.5 5 V
Output Voltage VO–0.5 VCC V
Output Current per Channel IO–0.2 9 mA
3
Recommended Operating Conditions
Parameter Symbol Min. Typ. Max. Units Notes
Temperature T –10 25 85 ˚C
Supply Voltage VCC 3 3.3 3.5 V Ripple < 100 mV p-p
LED Current ILED 13 16 18 mA See ”Current Limiting Resistor
for LED“
Load Capacitance CL100 pF
Pull-Up Resistor RLnone KΩRecommend no pull-up.
Device has integrated 2.5 KΩ
on outputs.
Count Frequency 15 kHz (Velocity (rpm) x N)/60
Redial Misalignment ER± 0.38 mm
(± 0.015) (in.)
Tangential Misalignment ET± 0.38 mm
(± 0.015) (in.)
Angular Misalignment EA0.0 ± 1.5 deg.
Codewheel or Codestrip G 0.2 1.4 2.00 mm 1.4 mm is the recommended
Gap gap but the unit can operate
from 0.2 to 2 mm with no
problem
Codewheel or Codestrip Rf60% As other rose products,
Specular Reflectance eg., HEDR-8100 series
Codewheel/Codestrip Tilt CT0 1 deg.
Codewheel/Codestrip LPmm 5.91 lines/mm HEDR-8130 is 150 lpi
Resolution (LPI) (150) (lines/in.)
Encoding Characteristics
Encoding Characteristics over Recommended Operating Conditions and Mounting Conditions.
Parameter Symbol Typical Max. Units Notes
Pulse Width Error P 16 75 ˚e HEDR-8130
Phase Error φ10 60 ˚e HEDR-8130
State Error S 30 75 ˚e HEDR-8130
4
Current Limiting Resistor for LED
A resistor to limit current to the
LED is required. The recomended
value is 110 Ω (±10%) and
should be placed in series be-
tween the 3.3 V supply and pin 8
of the device (VLED). This will
result in an LED current of
approximately 16 mA.
Recommended Codewheel and Codestrip Characteristcs
Table 1.
Parameter Symbol Min. Max. Units Notes
Window/Bar Ratio Ww/Wb 0.9 1.1
Specular Reflectance Rf 60 85 Reflective Bars
– 10 Non-reflective Bars
Line Density LPmm 5.91 lines/mm
(LPI) (150) (lines/inch)
Window Length Lw 1.80 2.31 mm mm
(0.071) (0.091) (inches) (inches)
Electrical Characteristics
Electrical Characteristics over Recommended Operating Conditions. Typical Values at 25˚C.
Parameter Symbol Min. Typ. Max. Units Notes
Supply Current ICC 35mA
High Level Output Voltage VOH 2.4 3.3 V IOH = –140 µA
Low Level Output Voltage VOL 0.4 V IOL = 8 mA
Rise Time tr150 200 ns CL = 25 pF
RL = 2.7 KΩ
Fall Time tf50 60 ns
R
OP
W
b
W
w
L
w
L
w
W
w
W
b
5
Mounting Conditions
IR Soldering Conditions
The following recommended IR
soldering profile meets the speci-
fications of the Electronic Indus-
tries Association of Japan (EIAJ):
1. 150 ± 10˚C for 90 ±
30 seconds
2. Greater than 200˚C for 30 ±
10 seconds
3. 230 ± 5˚C for 10 ± 1 seconds
R
OP
1
2
3
4
8
7
6
5
11.00 mm (0.433 IN.) < R
OP
< ∞
90 ± 30 S
30 ± 10 S
10 ± 1 S
235°C MAX.
230°C ± 5°C
200°C
TIME (S)
TEMPERATURE (°C)
150°C ± 10°C
Ordering Information
H E D R - 8 1 3 0 Opt 2
signifies 3.3 V
Lines/Inch
P = 150 lpi Units in Shipping Tube
4 = 1500 units
6
Outline Drawing
6.20 ± 0.20
(0.244 ± 0.008)
1.270 ± 0.025
(0.050 ± 0.001)
1234
8765
3.937 ± 0.076 *
(0.155 ± 0.003)
REF.
0.381 ± 0.050
(0.016 ± 0.002)
3.175 ± 0.076
(0.125 ± 0.003)
5.080 ± 0.100 *
(0.200 ± 0.004)
1.40 ± 0.20
(0.055 ± 0.001)
0.076 ± 0.025
(0.003 ± 0.001)
1.877 / 1.775
(0.0739 / 0.0699)
LEAD COPLANARITY ± 0.051
(0.002)
0.228 ± 0.025
(0.009 ± 0.001)
0.59
(0.023)MIN.
0.18 ± 0.08
(0.007 ± 0.003)
1
2
3
4
8
7
6
5
NC
GND
A
V
CC
V
LED
NC
B
GND
NOTES:
1. DO NOT INCLUDE FLASH IN DIMENSIONS MARKED WITH AN *.
2. DEVICE MARKING ORIENTATION IS AS SHOWN.
DATE CODE IS YEAR/WORKWEEK (YYWW).
PART NUMBER IS XXXX.
3. DIMENSIONS IN MILLIMETERS (INCHES).
XXXX
YYWW
7
Appendix
Note: For Definitions in page 2 and
Electrical Characteristics in page 3.
P
CHANNEL B
CHANNEL A
ROTATION
AMPLITUDE
C
S1 S2
Φ
S3 S4
2.4 V
0.4 V
trtf
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distributors, please go to our web site.
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Data subject to change.
Copyright © 2002 Agilent Technologies, Inc.
May 3, 2002
5988-5014EN
