AVAGO HEDS-97EX Small optical encoder modules 200 lpi analog voltage output Datasheet

HEDS-97EX Series
Small Optical Encoder Modules
200 LPI Analog Voltage Output
Data Sheet
Description
Features
The HEDS-97EX series is a small and high performance
optical incremental encoder module. When operated in
conjunction with either a codewheel or codestrip, this
module detects rotary or linear position. The encoder
module consists of a lensed LED source and a detector
IC enclosed in a small C-shaped plastic package. Due to a
highly collimated light source and a unique photodetector array, the module is extremely tolerant to mounting
misalignment.
• Small size
The two channel analog outputs and 3.3V supply input
are accessed through four solder-plated leads located on
2.54 mm (0.1 inch.) centers.
• RoHS compliant
HEDS-97EX is designed for use with an appropriate
optical radius codewheel. Please contact factory for more
information.
• Multiple mounting options
• Insensitive to radial and axial play
• 0°C to +60°C recommended operating temperature
• Two channel analog output
• Single 3.3V supply
• Wave solderable
Specifications
• 200 LPI
• 3.3V supply*
* Typical conditions
Applications
• Printers
• Copiers/Fax
• Plotters
• Office automation equipments
ESD WARNING: NORMAL PRECAUTIONS SHOULD BE TAKEN TO AVOID STATIC DISCHARGE.
Theory of Operation
Definitions
The HEDS-97EX is a C-shaped emitter/detector module.
Coupled with a codewheel/codestrip, it translates rotary
motion into a two-channel analog output.
Count (N): The number of bar and window pairs or counts
per revolution (CPR) of the codewheel. Or the number of
lines per inch of the codestrip (LPI)
The module contains a single Light Emitting Diode (LED)
as its light source. The light is collimated into a parallel
beam by means of a single lens located directly over the
LED. Opposite the emitter is the integrated detector
circuit. This IC consists of multiple sets of photodetectors
and the signal processing circuitry necessary to produce
the analog waveforms.
1 shaft rotation = 360 degrees
= N cycles
The codewheel/codestrip moves between the emitter
and detector, causing the light beam to be interrupted
by the pattern of spaces and bars on the codewheel/
codestrip.
The photodiodes, which detect these interruptions, are
arranged in a pattern that corresponds to the radius and
count density of the codewheel/codestrip.
These detectors are also spaced such that a light period
on one pair of detectors corresponds to a dark period on
the adjacent pairs of detectors. The photodiode outputs
are fed through the signal processing circuitry, which
produce the final outputs for Channel A and Channel
B. Due to this integrated phasing technique, the analog
output of Channel A is in quadrature with Channel B (90
degrees out of phase).
1 cycle (c)
= 360 electrical degree, equivalent to 1
bar and window pair.
Direction of Rotation: When the codewheel rotates in the
counter-clockwise direction (as viewed from the encoder
end of the motor), channel A will lead channel B. If the
codewheel rotates in the clockwise direction, channel B
will lead channel A.
Line Density: The number of window and bar pair per
unit length, express in either lines per inch (LPI) or lines
per mm (LPmm)
Optical Radius (Rop): The distance from the codewheel’s
center of rotation to the optical center (O.C) of the
encoder module.
Gap (G): The distance from surface of the encoder to the
surface of codewheel or codestrip
Mounting Position (RM): Distance from Motor Shaft
center of rotation to center of Alignment Tab receiving
hole.
Radial and Tangential Misalignment Error (ER and Er): For
rotary motion mechanical displacement in the radial and
tangential directions relative to the nominal alignment
Angular Misalignment Error (EA): Angular misalignment
of the sensor in relation to then tangential direction.
This applies for both rotary and linear motion.of electrical degrees that an output is high during one cycle,
nominally 180°e or 1/2 a cycle.
Absolute Maximum Ratings
Subjecting the part to stresses beyond those listed under this section may cause permanent damage to the device.
These are stress ratings only and do not imply that the device functions beyond these ratings. Exposure to the
extremes of these conditions for extended periods may affect device reliability.
Parameter
Symbol
Min.
Max.
Units
Storage Temperature
TS
-40
85
°C
Operating Temperature
TA
0
60
°C
Supply voltage (Detector)
VCC
-0.5
7
V
Output Voltage
Va , Vb
-0.5
VCC + 0.4
V
260
°C
t ≤ 7 sec
Soldering Temperature
Notes
DC Forward current (LED)
ILED
50
mA
VF < 1.8V
Reverse Voltage
VR
5
V
IR = 100uA
Recommended Operating Conditions
Parameter
Symbol
Min.
Typ.
Max.
Units
Notes
Operating Temperature
T
0
25
60
°C
Supply Voltage (Detector)
VCC
3.15
3.3
3.45
V
Ripple < 100mVpp
Output Frequency
f
8
40
KHz
(Velocity (rpm) x N)/60
DC Forward Current (LED)
ILED
26
mA
Electrical Characteristics
Electrical Characteristics over Recommended Operating Range, typically at 25°C
Parameter
Symbol
Supply Current (Detector)
ICC
LED Forward Voltage
VF
Min.
1.3 (turn on)
1.5 (operate)
Typ.
Max.
Units
5
8
mA
1.44
1.54
V
Notes
Typical If = 24mA
Encoding Characteristics
Parameter
Symbol
Min (b)
Max (b)
Units
State width error
DS
-40
+40
°e
Pulse width error
DP
-40
+40
°e
Peak to Peak voltage
VppA
VppB
1
3
V
Analog offset voltage
Voffset A
Voffset B
-150
150
mV
Notes:
(a) Obtained at typical conditions specified in “Recommended Operating Conditions” and nominal mounting position (Radial, Tangential, Gap) of
(0,0, 0)
(b) Obtained over the whole “Recommended Operating Conditions” and “Part Mounting Tolerances”
Waveform Definition
Ch A
Vpp
1.65 voltage
offset reference
Ch B
PA
PB
S1
S2
S3
S4
Test Parameter Definitions
Parameter
Symbol
Definition
Units
Analog peak voltage
Vap, Vbp,
Vam, Vbm
The absolute value in V of the magnitude of the analog signal
(i.e. one sided rating)
V
Analog peak to peak voltage
Vpp
The peak to peak signal magnitude in mA of the analog signal
V
Analog peak to peak ratio
VppA/VppB
The ratio of A channel peak analog signal to B channel peak analog signal
V
Analog Crossing
Vx12, Vx34, Vx56, Vx78 The intersection in V of the A channel analog waveform with either the B channel analog V
waveform or its compliment.
Analog Offset current
Voffset
The offset in V from the mid-point of the analog peak to peak signal to zero current
State Width
S1, S2, S3, S4
The number of electrical degrees between a transition in channel A and the neighboring °e
transition in channel B. There are 4 state per cycle, each nominally 90°e. The transitions
are determined by where the analog signal crosses the Zero point
State Width Error
DS1, DS2, DS3, DS4
The deviation in electrical degrees of each state width from its ideal value of 90°e.
°e
Pulse Width
PA,PB
The number of electrical degrees that an analog output is greater than zero during one
cycle. This value is nominally 180°e or ½ cycle.
°e
Pulse Width Error
DP
The deviation in electrical degrees of each pulse width from its ideal value of 180°e.
°e
V
Mounting Configuration
Error
Rop=19.40mm Unit
Notes
Recommend CW to put closer to the detector side (upper side), in order to give
enough margin for encoder operation.
Eg
Gap
0.05 to 0.65
mm
Er
Radial
±0.13
mm
Et
Tangential
±0.13
mm
Ea
Angular
±3
Deg.
4.25 ± 0.3
(0.17 ± 0.012)
5.32 MAX.
(0.2094)
SEE NOTE 1
Rm
CL OF ALIGNMENT TAB
Rop
6.30 MAX.
(0.248)
6.50 MIN.
(0.256)
2.03 MIN.
(0.080)
1.0 DEEP MIN.
(0.039)
2X R
Rm = Rop - 0.14 (0.006)
∅ 2.03 HOLE MIN.
(0.080)
NOTE: THESE DIMENSIONS INCLUDE SHAFT END PLAY AND CODEWHEEL WARP.
ALL DIMENSIONS FOR MOUNTING THE MODULE/CODESTRIP SHOULD BE MEASURED
WITH RESPECT TO THE TWO MOUNTING POSTS, SHOWN ABOVE.
DIMENSIONS IN MILLIMETERS (INCHES).
1.0 DEEP MIN.
(0.039)
Recommended Codewheel and Codestrip Characteristics
MAX 3.4 (0.134)
Wb
Ww
Lw
Rc
Rop
W1
W2
Ww Wb
Parameter
Symbol
Min.
Max.
Window/Bar Ratio
Ww/Wb
0.9
1.1
Window Length (Rotary)
Lw
1.80
(0.071)
3.0
(0.1181)
mm
(inch)
Absolute Maximum Codewheel Radius (Rotary)
Rc
Rop + 3.40
(Rop + 0.134)
mm
(inch)
Center of Post to Inside Edge of Window
W1
1.04
(0.041)
mm
(inch)
Center of Post to Outside Edge of Window
W2
0.76
(0.030)
mm
(inch)
Center of Post to Inside Edge of Codestrip
L
3.60
(0.142)
Units
mm
(inch)
Notes
Includes eccentricity errors
Package Dimensions
HEDS-97E0-R50 (Bracket 50)
1.4
0.055
2x ∅
7.5
0.295
2.00
0.079
15.0
0.591
10.1
0.398
3.0
0.118
0.8
0.031
20.2
0.795
10.8
0.425
9.8
0.386
4.2
0.167
1.7
0.667
3.9
0.154
YYWW
3.9
0.152
0.14
0.006
7.0
0.276
50
5.0
0.198
97EX
6.4
0.252
GND
R 1.4
0.055
5.5
0.217
LEAD THICKNESS: 0.25
0.010
VCC
CH A
0.50
0.020
(OPTICAL CENTER)
CH B
3.8
0.150
1.8
0.071
12.6
0.496
HEDS-97E0-R54 (Bracket 54)
(OPTICAL CENTER)
97EX
6.4
0.252
3.9
0.152
0.14
0.006
2x ∅
YYWW
54
5.5
0.217
4.9
0.193
2.00
0.079
3.0
0.118
9.8
0.386
10.8
0.425
0.8
0.031
4.2
0.167
1.7
0.667
3.9
0.154
HEDS-97E1-R54 (BEND LEAD)
3.0
0.118
5° TYP
9.2
0.362
3.8
0.150
0.50
0.020
0.25
0.010
GND
CH B
0.50
0.020
VCC
CH A
LEAD THICKNESS:
3.8
0.150
12.6
0.496
Recommended Wave Solder Profile
7 sec Max
260ºC
Temperature (ºC)
A
B
C
Reflow
120ºC/120 sec Max
Cool Down
Time (s)
Parameter
Min.
Max.
Nominal values
Units
A
Solder Pot Temperature
NA
260
250 - 260
°C
B
Preheat Zone Temperature
85
120
100 - 120
°C
C
Dip in Time
5
7
5
sec
D
Solder Pot Zone (Encoder Lead)
200
260
NA
°C
Note:
- Nominal values are evaluated profiles for optimum performance.
- Min/Max are critical limits to ensure encoders in good condition.
Ordering Information
HEDS-97E
Option
Lead Configuration
0 - Straight Leads
1 - Bent Leads
Resolution Option
R - 200 LPI
Bracket Option
50
54
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, Limited in the United States and other countries.
Data subject to change. Copyright © 2006 Avago Technologies Limited. All rights reserved.
AV02-0184EN - March 28, 2007
Similar pages