AVAGO HEDM-55xx, HEDM-560x, HEDS-55xx, HEDS-56xx DATA SHEET

HEDM-55xx/560x & HEDS-55xx/56xx

Quick Assembly Two and Three Channel Optical Encoders

Data Sheet

HEDM-55xx/560x HEDS-550x/554x, HEDS-560x/564x

Description

The HEDS-5500/5540, HEDS-5600/5640, HEDM-5500/5540
and HEDM-5600 are high performance, low cost, two
and three channel optical incremental encoders. These
encoders emphasize high reliability, high resolution, and
easy assembly.

Each encoder contains a lensed LED source, an integrated
circuit with detectors and output circuitry, and a codewheel
which rotates between the emitter and detector IC. The
outputs of the HEDS-5500/5600 and HEDM-5500/ 5600
are two square waves in quadrature. The HEDS-5540/5640
and HEDM-5540 also have a third channel index output in
addition to the two channel quadrature. This index output
is a 90 electrical degree, high true index pulse which is
generated once for each full rotation of the codewheel.

The HEDS series utilizes metal codewheels, while the
HEDM series utilizes a lm codewheel allowing for resolu­tions to 1024 CPR.

These encoders may be quickly and easily mounted to a
motor. For larger diameter motors, the HEDM-5600, and
HEDS-5600/5640 feature external mounting ears.

The quadrature signals and the index pulse are accessed
through ve 0.025 inch square pins located on 0.1 inch
centers.

Standard resolutions between 96 and 1024 counts per
revolution are presently available. Consult local Avago
sales representatives for other resolutions.

Features

• Two channel quadrature output with optional index

pulse

• Quick and easy assembly

• No signal adjustment required

• External mounting ears available

• Low cost

• Resolutions up to 1024 counts per revolution

• Small size –40°C to 100°C operating temperature

• TTL compatible

• Single 5 V supply

Applications

The HEDS-5500, 5540, 5600, 5640, and the HEDM-5500,
5540,5600 provide motion detection at a low cost, making
them ideal for high volume applications. Typical applica­tions include printers, plotters, tape drives, positioning
tables, and automatic handlers.

Note: Avago 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 clarication is needed.

ESD WARNING: NORMAL HANDLING PRECAUTIONS SHOULD BE TAKEN TO AVOID STATIC DISCHARGE.

Package Dimensions

HEDS-5500/5540, HEDM-5500/5540

*Note: For the HEDS-5500 and HEDM-5500, Pin #2 is a No Connect. For the HEDS-5540 and HEDM-5540, Pin #2 is CH. I, the index output.

HEDS-5600/5640, HEDM-5600

*Note: For the HEDS-5600 and HEDM-5600, Pin #2 is a No Connect. For the HEDS-5640, Pin #2 is CH. I, the index output.

2

Theory of Operation

The HEDS-5500, 5540, 5600, 5640, and HEDM-5500, 5540,
5600 translate the rotary motion of a shaft into either a
two- or a three-channel digital output.

As seen in the block diagram, these encoders contain a
single Light Emitting Diode (LED) as its light source. The
light is collimated into a parallel beam by means of a
single polycarbonate 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
digital waveforms.

The codewheel rotates between the emitter and detector,
causing the light beam to be interrupted by the pattern
of spaces and bars on the codewheel. The photodi­odes which detect these interruptions are arranged in a
pattern that corresponds to the radius and design of the
codewheel. These detectors are also spaced such that a
light period on one pair of detectors corresponds to a
dark period on the adjacent pair of detectors. The photo­diode outputs are then fed through the signal processing
circuitry resulting in A, A, B and B (also I and I in the HEDS­5540/5640 and HEDM-5540). Comparators receive these
signals and produce the nal outputs for channels A and
B. Due to this integrated phasing technique, the digital
output of channel A is in quadrature with that of channel
B (90 degrees out of phase).

In the HEDS-5540/5640 and HEDM-5540, the output of
the comparator for I and I is sent to the index processing
circuitry along with the outputs of channels A and B.

The nal output of channel I is an index pulse PO which
is generated once for each full rotation of the codewheel.
This output PO is a one state width (nominally 90 electri­cal degrees), high true index pulse which is coincident
with the low states of channels A and B.

Block Diagram

Denitions

Count (N): The number of bar and window pairs or counts
per revolution (CPR) of the codewheel.

One Cycle (C): 360 electrical degrees (°e), 1 bar and window
pair.

One Shaft Rotation: 360 mechanical degrees, N cycles.

Position Error (∆Θ): The normalized angular dierence

between the actual shaft position and the position
indicated by the encoder cycle count.

Cycle Error (∆C): An indication of cycle uniformity. The
dier¬ence between an observed shaft angle which
gives rise to one electrical cycle, and the nominal angular
increment of 1/N of a revolution.

Pulse Width (P): The number of electrical degrees that an
output is high during 1 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
transition in the output of channel A and the neighbour­ing transition in the output of 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 (φ): The number of electrical 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.

Note: Circuitry for CH I is only for HEDS-5540, 5640 and HEDM 5540 Three Channel Encoder

3

Absolute Maximum Ratings

Parameter HEDS-55XX/56XX HEDM-550X/560X HEDM-5540

Storage Temperature, TS -40°C to 100°C -40°C to +70°C -40°C to 100°C

Operating Temperature, TA -40°C to 100°C -40°C to +70°C -40°C to 100°C

Supply Voltage, VCC -0.5 V to 7 V -0.5 V to 7 V -0.5 V to 7 V

Output Voltage, VO -0.5 V to VCC -0.5 V to VCC -0.5 V to VCC

Output Current per Channel, I

Vibration 20 g, 5 to 1000 Hz 20 g, 5 to 1000 Hz 20 g, 5 to 1000 Hz

Shaft Axial Play ± 0.25 mm

Shaft Eccentricity Plus Radial Play 0.1 mm

Velocity 30,000 RPM 30,000 RPM 30,000 RPM

Acceleration 250,000 rad/sec2 250,000 rad/sec2 250,000 rad/sec2

-1.0 mA to 5 mA -1.0 mA to 5 mA -1.0 mA to 5 mA

OUT

(± 0.010 in.)

(0.004 in.) TIR

± 0.175 mm
(± 0.007 in.)

0.04 mm
(0.0015 in.) TIR

± 0.175 mm
(± 0.007 in.)

0.04 mm
(0.0015 in.) TIR

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.

Output Waveforms

Index Pulse Width (PO): The number of electrical degrees that
an index output is high during one full shaft rotation. This
value is nominally 90°e or 1/4 cycle.

4

Recommended Operating Conditions

Parameter Sym. Min. Typ. Max. Units Notes

Temperature HEDS Series TA -40 100 °C

Temperature HEDM Series 5500/5600 TA -40 70 °C non-condensing

5540 T

A

-40 100 °C

Supply Voltage VCC 4.5 5.0 5.5 Volts Ripple < 100 mVp-p

Load Capacitance CL 100 pF 2.7 kΩ pull-up

Count Frequency f 100 kHz Velocity (rpm) x N/60

Shaft Perpendicularity
Plus Axial Play (HEDS Series)

Shaft Eccentricity Plus
Radial Play (HEDS Series)

Shaft Perpendicularity
Plus Axial Play (HEDM Series)

Shaft Eccentricity Plus
Radial Play(HEDM Series)

Note: The module performance is guaranteed to 100 kHz but can operate at higher frequencies. 2.7 kΩ pull-up resistors required for HEDS­5540/5640 and HEDM-5540.

± 0.25

(±0.010)

0.04

(0.0015)

± 0.175

(±0.007)

0.04

(0.0015)

mm
(in.)

mm (in.)

TIR

mm
(in.)

mm (in.)

TIR

atmosphere

6.9 mm (0.27 in.)
from mounting surface

6.9 mm (0.27 in.)
from mounting surface

6.9 mm (0.27 in.)
from mounting surface

6.9 mm (0.27 in.)
from mounting surface

Encoding Characteristics

Part No. Description Sym. Min Typ.* Max. Units

HEDS-5500
HEDS-5600
(Two Channel)

HEDM-5500
HEDM-5600
(Two Channel)

HEDS-5540
HEDS-5640
(Three Channel)

HEDM-5540
(Three Channel)

Note: See Mechanical Characteristics for mounting tolerances. *Typical values specied at VCC = 5.0 V and 25°C.

Pulse Width Error
Logic State Width Error
Phase Error
Position Error
Cycle Error

Pulse Width Error
Logic State Width Error
Phase Error
Position Error
Cycle Error

Pulse Width Error
Logic State Width Error
Phase Error
Position Error
Cycle Error
Index Pulse Width

CH.I rise after

-40°C to +100°C t

CH.A or CH. B fall

CH.I fall after

-40°C to +100°C t

CH.A or CH. B rise

Pulse Width Error
Logic State Width Error
Phase Error
Position Error
Cycle Error
Index Pulse Width

CH.I rise after

-40°C to +100°C t

CH.A or CH. B fall

CH.I fall after

-40°C to +100°C t

CH.A or CH. B rise

∆P
∆S
∆Φ
∆Θ
∆C

∆P
∆S
∆Φ
∆Θ
∆C

∆P
∆S
∆Φ
∆Θ
∆C
Po 55

1

2

-300 100 250 ns

70 150 1000 ns

∆P
∆S
∆Φ
∆Θ
∆C
Po 50

1

2

200 1000 1500 ns

0 300 1500 ns

7
5
2
10
3

10
10
2
10
3

5
5
2
10
3
90

10
10
2
10
6
90

45
45
20
40

5.5

45
45
15
40

7.5

45
35
15
40

5.5
125

45
45
15
40
12
130

°e
°e
°e
min. of arc
°e

°e
°e
°e
min. of arc
°e

°e
°e
°e
min. of arc
°e
°e

°e
°e
°e
min. of arc
°e
°e

5

Electrical Characteristics

Electrical Characteristic over Recommended Operating Range

Part No. Parameter Sym. Min Typ.* Max. Units Notes

HEDS-5500
HEDS-5600

HEDS-5540
HEDS-5640
HEDM-5500
HEDM-5600

HEDM-5500
HEDM-5600

HEDM-5540 Supply Current

* Typical values specied at VCC = 5.0V and 25ºC

Supply Current
High Level Output Voltage
Low Level Output Voltage

Rise Time
Fall Time

Supply Current
High Level Output Voltage
Low Level Output Voltage

Rise Time
Fall Time

Supply Current
High Level Output Voltage
Low Level Output Voltage

Rise Time
Fall Time

High Level Output Voltage
Low Level Output Voltage

Rise Time
Fall Time

I

CC

V

2.4

OH

V

OL

t

r

t

f

30

I

CC

2.4

V

OH

V

OL

t

r

t

f

I

30

CC

V

2.4

OH

V

OL

t

r

t

f

I

30

CC

V

2.4

OH

V

OL

t

r

t

f

17 40

0.4

200
50

57 85

0.4

180
40

57 85

0.4

180
40

57 85

0.4

200
80

mA
V
V

ns
ns

mA
V
V

ns
ns

mA
V
V

ns
ns

mA
V
V

ns
ns

IOH = -40�A max�A maxA max
IOL= 3.2mA

CL= 25 pF
RL = 11 kΩ pull-up

IOH = -200�A max�A maxA max
IOL= 3.86mA

CL= 25 pF
RL = 2.7 kΩ pull-up

IOH = -40�A max�A maxA max
IOL= 3.86mA

CL= 25 pF
RL = 3.2 kΩ pull-up

IOH = -200�A max�A maxA max
IOL= 3.86mA

CL= 25 pF
RL = 2.7 kΩ pull-up

6

Mechanical Characteristics

Parameter Symbol Dimension Tolerance

Codewheel Fits These Standard
Shaft Diameters

Moment of Inertia J 0.6 (8.0 x 10-6) g-cm2 (oz-in-s2)

Required Shaft Length[2] 14.0 (0.55) ± 0.5

Bolt Circle[3] 2 screw mounting 19.05

3 screw mounting 20.90

external mounting ears 46.0

Mounting Screw Size[4] 2 screw mounting M 2.5 or (2-56) mm (in.)

3 screw mounting M 1.6 or (0-80) mm (in.)

external mounting ears M 2.5 or (2-56) mm (in.)

Encoder Base Plate Thickness 0.33 (0.130) mm (in.)

Hub Set Screw (2-56) (in.)

Notes:

1. These are tolerances required of the user.

2. The HEDS-55X5 and 56X5, HEDM-5505, 5605 provide an 8.9 mm (0.35 inch) diameter hole through the housing for longer motor shafts. See
Ordering Information.

3. The HEDS-5540 and 5640 must be aligned using the aligning pins as specied in Figure 3, or using the alignment tool as shown in “Encoder
Mounting and Assembly”. See also “Mounting Considerations.”

4. The recommended mounting screw torque for 2 screw and external ear mounting is 1.0 kg-cm (0.88 in-lbs). The recommended mounting screw
torque for 3 screw mounting is 0.50 kg-cm (0.43 in-lbs).

2 3 4
5 6 8

5/32 1/8
3/16 1/4

(0.750)

(0.823)

(1.811)

+0.000

-0.015

+0.0000

-0.0007

(± 0.02)

± 0.13
(± 0.005)

± 0.13
(± 0.005)

± 0.13
(± 0.005)

[1]

Units

mm

in

mm (in.)

mm (in.)

mm (in.)

mm (in.)

Electrical Interface

To insure reliable encodingperformance, the HEDS­5540/5640 and HEDM-5540 three channel encoders
require 2.7 kΩ (± 10%) pull-up resistors on output pins 2, 3,
and 5 (Channels I, A, and B) as shown in Figure 1. These pull­up resistors should be located as close to the encoder as
possible (within 4 feet). Each of the three encoder outputs

Figure 1. Pull-up Resistors on HEDS-5X40 and HEDM-5540 Encoder Outputs.

can drive a single TTL load in this conguration. The HEDS­5500, 5600, and HEDM-5500, 5600 two channel encoders
do not normally require pull-up resistors. However, 3.2
kΩ pull-up resistors on output pins 3 and 5 (Channels A
and B) are recommended to improve rise times, especially
when operating above 100 kHz frequencies.

7

Mounting Considerations

The HEDS-5540 and 5640 three channel encoders and the
HEDM Series high resolution encoders must be aligned
using the aligning pins as specied in Figure 3, or using
the HEDS-8910 Alignment Tool as shown in Encoder
Mounting and Assembly.

The use of aligning pins or alignment tool is recommend­ed but not required to mount the HEDS-5500 and 5600.
If these two channel encoders are attached to a motor
with the screw sizes and mounting tolerances specied
in the mechanical characteristics section without any

additional mounting bosses, the encoder output errors
will be within the maximums specied in the encoding
characteristics section. The HEDS-5500 and 5540 can be
mounted to a motor using either the two screw or three
screw mounting option as shown in Figure 2. The optional
aligning pins shown in Figure 3 can be used with either
mounting option. The HEDS-5600, 5640, and HEDM-5600
have external mounting ears which may be used for
mounting to larger motor base plates. Figure 4 shows the
necessary mounting holes with optional aligning pins and
motor boss.

Figure 2. Mounting Holes.

Figure 4. Mounting with External Ears.

Figure 3. Optional Mounting Aids.

8

Encoder Mounting and Assembly

1a. For HEDS-5500 and 5600: Mount encoder base plate

onto motor. Tighten screws. Go on to step 2.

1b. For HEDS-5540, 5640 and HEDM-5500, 5600, 5540 :

Slip alignment tool onto motor shaft. With alignment
tool in place, mount encoder baseplate onto motor
as shown above. Tighten screws. Remove alignment
tool.

1c. It is recommended that adhesive* is applied to the

screw-baseplate interface to prevent screw loosening
due to eect of high temperature on plastic

2. Snap encoder body onto base plate locking all 4

snaps.

3a. Push the hex wrench into the body of the encoder to

ensure that it is properly seated into the code wheel
hub set screws. Then apply a downward force on the
end of the hex wrench. This sets the code wheel gap
by levering the code wheel hub to its upper position.

3b. While continuing to apply a downward force, rotate

the hex wrench in the clockwise direction until the
hub set screw is tight against the motor shaft (The
recommended torque to tighten the setscrew is 15­18 ozf.inch). The hub set screw attaches the code
wheel to the motor’s shaft.

3c. Remove the hex wrench by pulling it straight out of

the encoder body.

4. Use the center screwdriver slot, or either of the two

side slots, to rotate the encoder cap dot clockwise
from the one dot position to the two dot position. Do
not rotate the encoder cap counterclockwise beyond
the one dot position.

The encoder is ready for use!

9

Connectors

42.50

1.673

31.40

1.236

14.00
.551

16.50

.650

7.20

.283

1. Dimensions are in

2. All tolerances are within ±0.5

millimeters

Inches

Manufacturer Part Number

AMP 103686-4

640442-5

Avago (designed to mechanically lock into the
HEDS-5XXX, HEDM-5X0X Series)

Molex 2695 series with 2759 series term.

HEDS-8902 (2 ch.) with 4-wire leads

HEDS-8903 (3 ch.) with 5-wire leads

Figure 5. HEDS-8902 nd 8903 connectors

Protective Silicon Cover

Protective Silicon Rubber cover gives an extra protection
for HEDS-5xx0 and HEDM-5xx0 family when operating in
dusty environment.

The protective silicon cover is installed to HEDS-5xx0
or HEDM-5xx0 prior to the connector to the encoder is
installed.

Part Number

Material

Used With

Temperature Range

HEDS-8907-001

Silicon Rubber- Semi transparent-ESD
protective material

HEDS-5xx0 and HEDM-5xx0

-40ºC to 100ºC

10

Shaft Diameter

01 - 2 mm 06 - 1/4 in.
02 - 3 mm 11 - 4 mm
03 - 1/8 in. 14 - 5 mm
04 - 5/32 in. 12 - 6 mm
05 - 3/16 in. 13 - 8 mm

Mounting Type

5 - Standard
6 - External

Mounting Ears

Resolution (Cycles/Rev)

B - 1000 CPR
J - 1024 CPR

Through Hole

0 - None
5 - 8.9 mm (0.35 in.)

Outputs

0 - 2 Channel

HEDS-8910 0 Alignment Tool

HEDM-5 0 Option

HEDS-5 Option

Shaft Diameter

01 - 2 mm 06 - 1/4 in.
02 - 3 mm 11 - 4 mm
03 - 1/8 in. 14 - 5 mm
04 - 5/32 in. 12 - 6 mm
05 - 3/16 in. 13 - 8 mm

Mounting Type

5 - Standard
6 - External

Mounting Ears

Through Hole

0 - None
5 - 8.9 mm (0.35 in.)

Outputs

0 - 2 Channel
4 - 3 Channel

4 - 3 Channel

HEDS-8910 0 Alignment Tool

Resolution (Cycles/Rev)

(HEDS-550X, 560X 2 Channel)

S - 50 CPR F - 256 CPR
K - 96 CP G - 360 CPR
C - 100 CPR H - 400 CPR
D - 192 CPR A - 500 CPR
E - 200 CPR I - 512 CPR

(HEDS-554X, 564X 3 Channel)

S - 50 CPR
K - 96 CPR
C - 100 CPR
E - 200 CPR
F - 256 CPR

G - 360 CPR
H - 400 CPR
A - 500 CPR
I - 512 CPR

Typical Interfaces

HOST

PROCESSOR

HEDS–55XX

OR

HEDS-56XX

OR

HEDM-5X0X

HCTL-20xx

QUADRATURE

DECODER/
COUNTER

CH. A

CH. B

HOST

PROCESSOR

CH. B

CH. A

HEDS–55XX

OR

HEDS-56XX

OR

HEDM-5X0X

HCTL-1100

MOTION

CONTROL IC

Ordering Information

Encoders with Film Codewheels

(Included with each order of HEDM-550X/560X two channel encoders and HEDM-554X three Channel encoders)

(Included with each order of HEDS-554X/564X three channel encoders)

11

01 02 03 04 05 06 11 12 13 14

HEDM-5500 B * * * * * * *

J * * * * *

HEDM-5505 B *

J * * *

HEDM-5540 B * * * * * *

HEDM-5545 B *

HEDM-5600 B * *

J *

HEDM-5605 B *

J *

HEDS-5500 A * * * * * * * * * *

C * * * * * * * * * *

E * * * * * * *

F * * * * * * * *

G * * * * *

H * * * *

I * * * * * * * * * *

K * * * *

S *

HEDS-5505 A * * * *

C * * * *

E * * *

F * * *

G * *

H * *

I * * *

K *

HEDS-5540 A * * * * * * * * * *

C * * * * * * *

E * * *

F * * *

G *

H * *

I * * * * * * *

01 02 03 04 05 06 11 12 13 14

HEDS-5545 A * *

C *

H * *

I *

HEDS-5600 A * * * *

C * * *

E *

G * *

H * *

I * *

HEDS-5605 A * *

C *

E *

F *

G *

H * *

I *

HEDS-5640 A * * *

E *

F *

H *

HEDS-5645 A * * *

C *

E *

G *

H * * *

I *

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 © 2007 Avago Technologies Limited. All rights reserved.
AV02-1046EN - February 29, 2008