HEDR-54xx Series
Mid-Sized Housed Encoder
Data Sheet
ESD WARNING: Normal Handling Precautions should be taken to avoid static discharge.
Description
The HEDR-542x series are high performance, cost-e ec-
tive, two-channel optional incremental housed encoders.
These encoders emphasize high reliability, high resolution,
and easy assembly. The HEDR-542x housed encoders use
re ective technology to sense rotary position. This sensor
consists of an LED light source and a photodetector IC in
a single SO-8 surface mount package. The outputs of the
HEDR-542x encoders are two square waves in quadrature.
These encoders may be quickly and easily mounted to a
motor.
Applications
The HEDR-542x provides motion detection at a low cost,
making them ideal for high volume applications. Typical
applications include vending machines and motor manu-
facturing applications.
Note: Avago Technologies encoders are not recommend-
ed for use in safety critical applications. Eg. ABS braking
systems, power steering, life support systems and critical
care medical equipment. Please contact sales representa-
tive if more clari cation is needed.
Available Styles
Features
 Two channel quadrature output
 Quick and easy assembly
 Cost-e ective
 Ideal for small motor systems
 -10° C to +85 °C operating temperature
 Right angle connector available
 Hub available in either a set screw con guration or a
press- t/adhesive mount con guration
 External mounting ears available
Right angle version (shown here with press
t/adhesive mount hub option)
External mounting ears version (shown here
with set screw type hub)
2
Package Dimensions
15.217.9
5.0
Ø23.0
2.0
46.0
52.0
8.5
11.7 13.9 14.4
1.5
B+5 A GND
Ø23.0
15.2 17.4 17.9
5.0
Ø23.0
NOTE: TYPICAL DIMENSIONS IN MILLIMETERS
11.7 13.9
1.5
B+5 A GND
Ø23.0
DETAIL A DETAIL A
B+5 V ANC GND
DETAIL B
DETAIL B
GND NC A +5 V B
3
Theory of Operation
The HEDR-542X translates rotary motion of a shaft into a
two channel digital output. As seen in the block diagram,
the HEDR-542X series has three key parts: a single Light
Emitting Diode (LED) light source, a photodetector IC
with a set of uniquely con gured photodiodes, and a pair
of lenses. The lens over the LED focuses light onto the
codewheel. Light is either re ected or not re ected back
to the lens over the photodetector IC. As the codewheel
rotates an alternating pattern of light and dark corre-
sponding to the pattern of the codewheel falls upon the
photodiodes. This light is used to produce internal signals
A and A', and B and B'. As part of this "push-pull" detector
system, these signals are fed through comparators that
are part of the signal processing circuitry to produce the
nal outputs for channels A and B.
Defi nitions
Count (N): For rotary motion, the number of bar and window
pairs or Counts Per Revolution (CPR) of the codewheel. For
linear motion, the number of bar and window pairs per
unit length (Lines Per Inch [LPI] or Lines Per mm [LPmm]).
One Cycle (C): 360 electrical degree (°e), 1 bar and window
pair.
One Shaft Rotation: 360 mechanical degrees, N cycles
(rotary motion only).
Line Density: The number of re ective and non-re ective
pairs per unit length, expressed as either Lines Per Inch
(LPI) or Lines Per mm (LPmm).
Pulse Width (P): The number of electrical degrees that an
output is high during one cycle, nominally 180°e or 1/2
a 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 the electrical degrees
between a transition in the output of the channel B. There
are 4 states per cycle, each nominally 90°e.
State Width Error (S): The deviation in electrical degrees of
each state width from its ideal value of 90°e.
Phase (): The number of electrical degrees between the
center of the high state on the channel A and the center
of the high state of channel B. This value is nominally 90°e.
Phase Error (): The deviation in electrical degrees of the
phase from its ideal value of 90°e.
SIGNAL
PROCESSING
CIRCUITRY
R
VLED
GND
VCC
CH A
CH B
GND
CODEWHEEL
Output Waveforms
Direction of Motor Rotation
When the codewheel rotates in the
clockwise direction (as viewed from the
encoder end of the motor), channel A will
lead channel B. If the codewheel rotates in
the counterclockwise direction, channel B
will lead channel A.
C
P
S1 S2 S3 S4 Ø
CH. I
CH. A
CH. B
CODEWHEEL ROTATION
AMPLITUDE
ALL FOUR STATES (S1 TO S4)
ARE MAINTAINED
4
Absolute Maximum Ratings
Storage Temperature -40° C to +85° C
Operating Temperature -10°-C to +85°-C
Supply Voltage -0.5 V to 7 V
Output Voltage -0.5 V to VCC
Output Current per Channel -2.0 mA to 12 mA
Shaft Axial Play ± 0.25 mm
Shaft Eccentricity Plus Radial Play 0.04 mm
Radial Play between Housing and Cover 0.2 mm – 0.5 mm
Distance between Tip of Codewheel Shaft and PC Board 0.4 mm – 0.5 mm
Distance between Codewheel and Stopper before Reset 0.25 mm – 0.35 mm
Distance between Codewheel and Stopper after Reset 0.75 mm
Concentricity Misalignment between Mounted Base 0.12 mm
Plate Center Bore and Motor Shaft
Frequency 16 kHz
Recommended Operating Conditions
Parameter Symbol Min. Typical Max. Units Notes
Temperature TA085°C
Supply Voltage VCC 4.5 5.0 5.5 Volts Ripple < 100 mVp–p
LED Current ILED 13 15 18 mA
Load Capacitance CL100 pF 2.7 K Pull-Up
Electrical Characteristics
(Over recommended operating conditions. Typically at 25° C)
Parameter Symbol Min. Typical Max. Units Notes
Supply Current ICC 18 33 mA
High Level Output Voltage VOH 2.4 V IOH = –2 mA min.
Low Level Output Voltage VOL 0.4 V IOL = 12 mA max.
Encoding Characteristics
Parameter Symbol Typical Max. Units
Pulse Width Error P775°e
State Width Error S15 60 °e
Phase Error  15 60 °e
Position Error  50 120 arcmin
Cycle Error C10 45 °e
5
Mechanical Characteristics
Parameter Dimension Tolerance Units
Codewheel Fits these Standard Shaft Diameters
Press Fit/Adhesive Mount Hub
Set Screw Hub
2, 3, 4
2, 3, 4, 5, (1/8)
+0/–0.01
(+0/–0.0005)
mm
(in.)
Allowable Motor Shaft Length
Press Fit/Adhesive Mount Hub
Set Screw Hub (uses size M1.5 Allen wrench, not included)
Between 7.5 and 8.0
Between 7.5 and 11.5
mm
Bolt Circle Diameter (2 holes) 16 to 18 mm
Mounting Screw Size M2
M2.5, (2-56) for external
mounting ears
mm
(in.)
Electrical Interface
Pull up resistors on output pins 2, 3, and 5 have already
been integrated into the mid-sized encoder. Each of the
three encoder outputs can drive a single TTL load in this
con guration.
Connectors
The connector to be used with the mid-sized encoder
is Molex Part Number 51021-0500. This is a 5 connector
crimp wire to board connector.
The connector used on the encoder is orientation proof
type, 2 di erent cables con guration required for connec-
tion to right angle and axial angle type encoder.
Pins con guration HEDR-542x series
Pin 1 GND
Pin 2 NC
Pin 3 Ch.A
Pin 4 5 V
Pin 5 Ch.B
6
Standard Mounting
Mounting Considerations
The mid-sized encoder must be aligned using the optional aligning pins, as speci ed in Figure 1, by using the optional
motor boss shown in Figure 2, or by using an alignment tool or as shown in Encoder Mounting and Assembly.
Figure 2.
Figure 1.
Mounting with External Ears
OPTIONAL MOTOR BOSS -
DIAMETER 9.96/10.01
MAX HEIGHT 1.5
OPTIONAL ALIGNMENT PINS -
DIAMETER 1.940/2.007. 2 PLACES
ON 14.50 DIAMETER CIRCLE.
MAX HEIGHT 1.9
M2 2 PLACES EQUALLY SPACED
ON BOLT CIRCLE BETWEEN
16 AND 20
SHAFT LENGTH
SHAFT LENGTH
OPTIONAL ALIGNMENT PINS-
DIAMETER 1.940/2.007. 2 PLACES
ON 14.50 DIAMETER CIRCLE.
MAX HEIGHT 1.9
OPTIONAL MOTOR BOSS - DIAMETER 9.96/10.01
MAX HEIGHT 1.5
M2 2 PLACES EQUALLY SPACED
ON DIAMETER 46 BOLT CIRCLE
7
Encoder Mounting and Assembly
Press Fit Style Encoder
1. If not using optional alignment pins or motor boss to
locate the base plate, slip alignment tool onto motor
shaft. Slip encoder base plate into place on motor
as shown below. Tighten screws or attach with an
adhesive. If using alignment tool, remove it.
ALIGNMENT TOOL
BASE PLATE
MOTOR
2. Place the hub in the housing assembly on top of the
motor shaft. Lining up the guide (connector side) at
the bottom of the housing with the slot (indicator side)
on the encoder base plate, the housing latches should
be aligned to the respective baseplate catches now.
Press the housing assembly downward and slide the
hub into and along the shaft, until the 3 latches make
contact with the catches.
MOTOR SHAFT
LATCH
(3 POSITION)
CATCH
(3 POSITION)
INDICATOR
SLOT (INDICATOR SIDE)
INDICATOR
60.0°
NOTE:
THIS IS A TOP VIEW OF THE BASE PLATE.
INDICATOR IS ALSO INDICATING THE
CONNECTOR DIRECTION. ANGULAR OFFSET
TO OPTIONAL ALIGNMENT PIN IS 60°.
TOLERANCE FOR THE ANGLE IS ± 2°.
GUIDE
(CONNECTOR SIDE)
30.0°
8
4. Using the end of a pen or other appropriate tool,
press the triangular portion of the housing assembly
downward. Recommended force is between 3.5 kgf
to 4.0 kgf. This will set the codewheel and hub into
their proper position through the internalguide of the
triangular piece. When the triangular piece is released,
it should naturally spring back to its original position,
eliminating contact between the housing assembly
and the codewheel. The encoder is now ready for use.
3. Press down the housing assembly until it snaps into
place. Recommended force is 3.5 kgf minimum, 4.0 kgf
nominal, and 4.5 kgf maximum. Note that the encoder
is shipped such that the housing assembly and the
base plate are not being snapped together.
9
Set Screw Style Encoder
1. If not using optional alignment pins or motor boss to
locate the base plate, slip alignment tool onto motor
shaft. Slip encoder base plate into place on motor
as shown below. Tighten screws or attach with an
adhesive. If using alignment tool, remove it.
ALIGNMENT TOOL
BASE PLATE
MOTOR
2. Slip the set screw hub into the shaft. Proper  nger-wear must be worn to avoid contamination on codewheel surface
(top of hub). Place an Allen wrench into the socket of the set screw while aligning it on the Allen wrench groove.
Lining up the guide (connector side) at the bottom of the housing with the slot (indicator side) on the encoder
baseplate, the housing latches should be aligned to the respective baseplate catches. Move the housing assembly
downward until the 3 latches make contact with the catches.
HOUSING ASSEMBLY
GUIDE
(CONNECTOR
SIDE)
SLOT
(INDICATOR SIDE)
MOTOR SHAFT
SET SCREW HUB
ALLEN
WRENCH
ALLEN WRENCH GROOVE
10
4. Using the end of a pen or other appropriate tool,
press the triangular portion of the housing assembly
downward. Recommended force is between 3.5 kgf
to 4.0 kgf. Then apply a downward force on the end
of the Allen wrench. This sets the codewheel position
by levering the codewheel upward against internal
guide of the triangular piece. While continuing to
apply a downward force on both tools, rotate the Allen
wrench in the clockwise direction until the hub set
screw is tightened against the motor shaft. Remove the
Allen wrench by pulling it straight out of the housing
assembly. When the triangular piece is released, it
should naturally spring back to its original position,
eliminating contact between the housing assembly
and the codewheel. The encoder is now ready for use.
3. Press down the housing assembly, holding the set
screw and Allen wrench in their initial position until
the housing assembly snaps into place. Recommended
force is 3.5 kgf minimum, 4.0 kgf nominal, and 4.5 kgf
maximum.
MOTOR
ALLEN WRENCH
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. Obsoletes 5988-9450EN
AV02-3576EN - August 7, 2012
Ordering Information
*Note: Part numbers currently available:
a. HEDR-5420-ES201
b. HEDR-5420-ES202
c. HEDR-5420-ES203
d. HEDR-5420-ES211
e. HEDR-5420-ES214
f. HEDR-5421-EP111
Ordering Information for Alignment Tool
*HEDR-5 4 X X – X X X X X
Output
2 = 2 channel
Connector
0 = standard/axial
1 = right angle/radial
Shaft
01 = 2 mm
02 = 3 mm
03 = 1/8 inch
11 = 4 mm
14 = 5 mm
Hub
S2 = Set screw with mounting ears base plate
P1 = Press t without mounting ears base plate
Resolution
E = 200 CPR
Shaft
01 = 2 mm
02 = 3 mm
03 = 1/8"
11 = 4 mm
14 = 5 mm
HEDR-5900-000