SMD-01B

Optical Encoder IC

1. OVERVIEWThe SMD-01B is a high-precision optical encoder IC that employs a diffraction image projection method. It
incorporates an OEIC (Opto-Electric Integrated Circuit) and LED light source in a single package. Light emitted fromthe LED is projected onto a scale, and the reflected diffraction image is focused on a photodiode. The reflected light
contains position information that is recovered to detect the relative movement between the SMD-01B and the scale.
A photodiode array is used to reduce degradation in phase characteristics due to mounting alignment. This allows theSMD-01B to be mounted without monitoring the output signal, unlike conventional high-precision optical encoders
which typically need to be mounted and aligned while monitoring the output signal.

2. FEATURES
■
■
■
■
■
■
■
■

Package: Miniature clear-mold package (5.3mm  4.3mm  1.68mm)
Resolution: 5μm (using 20μm pitch pattern scale and A-phase/B-phase signal detection)
Optimized OEIC and optics design for easy mounting alignment
LED and OEIC fabricated in a single package
Adjustable LED brightness using external inputs
Analog (sine wave) outputSupply voltage: 3.13 to 5.25V
Current consumption: 12.2 mA

3. APPLICATIONS■ Precision stages■ Sliders■ Robots

4. BLOCK DIAGRAM
Scale

Non-reflective baseReflective grating

LED
VCC

SWL1
SWL2

SWV

Photodiodes

GND

Signal Processor IC

VA
VAB
VB
VBB
Vref

LED
DriverPhotodiode IC
SMD-01B

SMD-01B Data Sheet
DE220191-E001

2024.08
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SMD-01B

Optical Encoder IC

5. PIN LAYOUTSWL1114VSS

SWL2213NC

VDD

312VANC

411VAB

NC

510VB

NC

69VBB

SWV78

VREF

6. PIN DESCRIPTION
Number

Name

I/O

1

SWL1

I

LED brightness adjustment 1 ( pull up)

2

SWL2

I

LED brightness adjustment 2 ( pull up)

3

VDD-

Supply voltage

4NC-

No connection (leave open circuit)

5NC-

No connection (leave open circuit)

6

NC-

No connection (leave open circuit)

7

SWV

I

Reference voltage select input ( pull up)

8

VREF

O

Reference voltage output

9VBB

O

B-phase inverted analog signal (BB phase) output

10VBO

B-phase analog signal (B phase) output

11VABO

A-phase inverted analog signal (AB phase) output

12VAO

A-phase analog signal (A phase) output

13NC-No connection (leave open circuit)

14

VSS-Ground

SMD-01B Data Sheet
DE220191-E001

Description

2024.08
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SMD-01B

Optical Encoder IC

7. ABSOLUTE MAXIMUM RATINGS
VSS=0V
Parameter

SymbolConditions

Rating

Unit

note

Supply voltage range

VDD

Voltage between VDD and VSS-0.3 to +6.0

V*1

Input voltage range

VIN

SWL1 , SWL2 , SWV pins

-0.3 to VDD+0.3

V*1, *2

Output voltage range

VOUT

VA , VAB , VB , VBB ,VREF pins-0.3 to VDD+0.3

V*1, *2

Storage temperature range

TSTG-40 to +80°C*3-*1: Absolute maximum ratings are the values that must never be exceeded, even for a moment. This product maysuffer breakdown if any one of these parameter ratings is exceeded. Operation and characteristics are guaranteed
only when the product is operated at recommended supply voltage range.
*2: VDD is the VDD value of recommended operating conditions.
*3: When stored alone in nitrogen or vacuum atmosphere.

8. RECOMMENDED OPERATING CONDITIONS
VSS=0VParameter

Supply voltage

SymbolConditions

MINTYPMAX

Unit

Between VDD and VSS terminals
SWV = H

3.13

3.3

5.25

V

Between VDD and VSS terminals
SWV = L or H

4.75

55.25

VVDD

Operating temperature

Ta--20-60°C

Response speed

Rt-0-

2m/s

* Since it may influence the reliability if it is used out of the recommended operating conditions range, this productshould be used within this range.

SMD-01B Data Sheet
DE220191-E001

2024.08
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SMD-01B

Optical Encoder IC

9. ELECTRICAL CHARACTERISTICS
9.1. DC Characteristics
VDD = 5V , VSS = 0V ,Ta = 27C unless otherwise noted

Parameter

SymbolConditions

MIN

TYP

MAX

Current consumption 1

IDD1

SWL1 = H , SWL2 = H

412.2

23

Current consumption 2

IDD2

SWL1 = H , SWL2 = L

716.9

30

Current consumption 3

IDD3

SWL1 = L , SWL2 = H

1121.035.5

Current consumption 4

IDD4SWL1 = L , SWL2 = L

2613.5

Reference voltage 1

Vref1

SWV=H11.452

Reference voltage 2

Vref2

SWV=L
VDD = 5±0.25V

A-phasesignal offset voltage

VAO

AB-phasesignal offset voltage

VABO

B-phasesignal offset voltage

VBO

BB-phasesignal offset voltage

VBBO

Output voltage
fluctuation 1

ΔVO1

Output voltage
fluctuation 2

ΔVO2

HIGH-level
input voltage

VIH

LOW-level
input voltage

1.4

2.25

Unit

Pins

mA

VDD

V

VREF

3.2
VA

SWL1 = L , SWL2 = L
Variation from VREF

VAB
-0.25

-0.25

V
VB
VBB

Difference between
0µA and 50µA
sink current
Difference between
0µA and 50µA
source current

0-30mV-30-0-0.8*VDD-

VDD

V

VIL

-0-

0.2*VDDV

HIGH-level
input current

IIH

VIN=VDD-1-1µA

LOW-level
input current

IIL

VIN=VSS-20-1µA

SMD-01B Data Sheet
DE220191-E001

VREF
VA
VAB
VB
VBB

SWL1
SWL2
SWV

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SMD-01B

Optical Encoder IC

9.2. Analog Characteristics
VDD = 5V , VSS = 0V ,Parameter

SymbolA-phase output
signal amplitude

VAP-P

AB-phase output
signal amplitude

VABP-P

B-phase output
signal amplitude

VBP-P

BB-phase output
signal amplitude

VBBP-P

A-phase - B-phasedifference

DPConditions

MIN

Ta = 27C unless otherwise noted

TYP

MAX

Unit

Pins
VA

SWL1 = H , SWL2 = H
Standard scale conditions
Value of peak to peak

VAB
0.13

0.85

3VVB
VBB

Standard scale conditions

5090

130°

VA,VB

VB

VBO
VAP-P

VBP-P center
VBP-P

Vref1 (or Vref2)
VAP-P center

VAO
20μm
VA

VAO & VBO offsets represent the differences between the VA & VB cycle center lines and Vref1 (or Vref2).

9.3. Standard Scale Conditions
Electrical characteristics ratings apply under the following conditions.
Parameter

Scale

Mounting

SMD-01B Data Sheet
DE220191-E001

Conditions

Unit

Reflective surface
reflection factor

57%

Non-reflective surface
reflection factor

5%

Pattern

20µm pitch(10µm Cr line/10µm spacing)-Gap (ΔGap)

0.3mm

Yaw angle (Δθy)
Roll angle (Δθr)
Pitch angle (Δθp)

0°2024.08
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SMD-01B

Optical Encoder IC

10. FUNCTIONAL DESCRIPTIONThe SMD-01B IC emits 632nm center-wavelength visible light from the LED and projects the light through a slit
and onto a scale having a 20μm pitch (10μm lines/10μm spacing) grating pattern. The reflected diffraction image isfocused on a photodiode array to detect the relative movement between the IC and the scale. An analog signal (sinewave) with a cycle period of 20μm is output. The output signal is composed by the 90° phase difference A-phaseand B-phase diffraction signals.

10.1. LED Brightness Switching Function
The signal amplitude can be adjusted by adjusting the LED brightness. The LED brightness is adjusted byadjusting the LED current. The amplitude adjustment options are shown in the following table.
SWL1

HHLL

SWL2

HL

HL

A/B-phase analog signal amplitude

1.0

1.8

2.6

010.2. Reference Voltage Switching Function
The SMD-01B has a function for switching the reference voltage (Vref) by changing the setting of the SWV pin.
Set the reference voltage according to the required input conditions of the following stage circuit.

SMD-01B Data Sheet
DE220191-E001

2024.08
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SMD-01B

Optical Encoder IC

11. SCALE Mounting Conditions
The optical center position of encoder ic is offset from the physical center of the ic by 0.77mm (ΔY) in the verticaldirection and 0.0mm (ΔX) in the horizontal direction. If using a linear scale, only the offset in the scale width direction(ΔY) needs to be considered. If using a rotary scale, the scale offset in the horizontal direction (ΔX) must also be taken
into account.
Conditions of optimum optics of this product may vary due to mounting tolerance of optical elements, so thoroughevaluation is needed to set the conditions. Particularly when using small-diameter rotary scale, effect of alignment
conditions on signal amplitude and phase difference is greater than when using linear scale. Individualized alignment isrecommended to obtain better product characteristics.
Roll angle
Δθr
Scale

Yaw angleΔθyIC-scale alignment
centerIC (this product)
Gap
ΔθpΔGap

Pitch angle

IC-scale alignment centerIC center+SW
Scale width alignment center
Scale vertical offset ΔY-SW

IC center

Scale horizontal offset ΔX

Reference data:
Scale
Mounting

SMD-01B Data Sheet
DE220191-E001

Parameter
Scale width (±SW)
Scale vertical offset (ΔY)
Scale horizontal offset (ΔX)

Conditions±1 (min)
0.77
0.0Unitmmmmmm2024.087/12

SMD-01B

Optical Encoder IC

12. REFERENCE DATA
* NPC Standard Conditions Scale and IC Alignment

12.1. Alignment Characteristics
phase difference vs. gap

AB-phase signal amplitude vs. gap
100phase difference [°]Amplitude [%]8060402000.10

0.15

0.20

0.25 0.30 0.35
ΔGap [mm]

0.40

0.45

5432
10-1-2-3-4-5
0.1

0.50

0.2

Amplitude vs. Gap (ΔGap)

phase difference [°]Amplitude [%]806040200-1.0-0.50.0Δθy [°]

0.5

1.0

1.5543210-1-2-3-4-5-32.0-2

Amplitude vs. Yaw angle (Δθy)

AB-phase signal amplitude vs. rollphase difference [°]Amplitude [%]6040
200-1.0-0.50.0Δθr [°]

0.5

1.0

Amplitude vs. Roll angle (Δθr)

SMD-01B Data Sheet
DE220191-E001

0Δθy [°]

123

phase difference vs. roll

80-1.5-1

Phase difference vs. Yaw angle (Δθy)

100-2.00.5

phase difference vs. yaw

AB-phase signal amplitude vs. yaw-1.50.4

Phase difference vs. Gap (ΔGap)

100-2.00.3ΔGap [mm]1.52.0543210-1-2-3-4-5-3-2-10Δθr [°]123

Phase difference vs. Roll angle (Δθr)

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SMD-01B

Optical Encoder ICphase difference vs. pitch

AB-phase signal amplitude vs. pitch100

phase difference [°]Amplitude [%]

80
60
40
200-2.0-1.5-1.0-0.50.0
Δθp [°]

0.5

1.0

1.5

2.0

543210-1-2-3-4-5-3

Amplitude vs. Pitch angle (Δθp)-2-10Δθp [°]12

Phase difference vs. Pitch angle (Δθp)

12.2. Temperature Characteristics

Amplitude vs. Temperature (Ta)12.3. Frequency Characteristics

Amplitude vs. Frequency

SMD-01B Data Sheet
DE220191-E001

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SMD-01B

Optical Encoder IC

13. PACKAGE DIMENSIONSTop view(Unit : mm)

0.4±0.1

5.3±0.1

LED（0.3）

Side view2

4.3±0.1

0.6×6=3.6

GratingGold(Au)
electrodes
OEIC

IC center1.68±0.15

Side view1
Epoxy resin
Glass-epoxy substrate

0.6×6=3.6

0.3±0.075

Bottom view

0.6

SMD-01B Data Sheet
DE220191-E001

2024.08
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SMD-01B

Optical Encoder IC

14. PRECAUTION FOR USE
Wire involved in drive actuator should be placed as far away from SMD-01B and wire drawn out from SMD-01B(especially analog signal wire) as possible.
The closer, the larger the noise to encoder ic signal. More digital signal chatterings occur when the noise is larger,
and position detection accuracy is deteriorated.
Capacitors shown below should be placed on VDD wire and VSS wire of SMD-01B for protection against noise.

0.1μF(Place as close as possible to ic.)

10μF
(Regulator section)
5.0±0.25Vor
3.3V±0.17V

SMD-01B Data Sheet
DE220191-E001

1.SWL1

14.VSS

2.SWL2

13.NC

3.VDD

12.VA

4.NC

SMD-01B 11.VAB

5.NC

10.VB

6.NC

9.VBB

7.SWV

8.VREF2024.08
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SMD-01B

Optical Encoder IC

15. USAGE AND PRECAUTIONSThis product is designed and manufactured to the generally accepted standards of reliability as expected for use ingeneral electronic and electrical equipment, such as personal equipment, machine tools, and measurement
equipment. This product is not designed and manufactured to be used in any other special equipment requiringextremely high level of reliability and safety, such as aerospace equipment, nuclear power control equipment, medicalequipment, transportation equipment, disaster prevention equipment, security equipment.
If you wish to use this product in equipment requiring extremely high level of reliability, please contact our sales
department or representative in advance.
In the event that this product is used in such equipment, please take scrupulous care and apply fail-safe techniques
including redundancy and malfunction prevention in order to prevent damage to life, health, property, or infrastructureetc. in case there is some malfunction in the product.

Please pay your attention to the following points at time of using the products shown in this document.
1. The products shown in this document (hereinafter ”Products”) are designed and manufactured to the generally
accepted standards of reliability as expected for use in general electronic and electrical equipment, such as
personal equipment, machine tools and measurement equipment. The Products are not designed and manufactured
to be used in any other special equipment requiring extremely high level of reliability and safety, such as aerospaceequipment, nuclear power control equipment, medical equipment, transportation equipment, disaster prevention
equipment, security equipment. The Products are not designed and manufactured to be used for the apparatus thatexerts harmful influence on the human lives due to the defects, failure or malfunction of the Products.
If you wish to use the Products in that apparatus, please contact our sales section in advance.
In the event that the Products are used in such apparatus without our prior approval, we assume no responsibility
whatsoever for any damages resulting from the use of that apparatus.
2. NPC reserves the right to change the specifications of the Products in order to improve the characteristics orreliability thereof.
3. The information described in this document is presented only as a guide for using the Products. No responsibility is
assumed by us for any infringements of patents or other rights of the third parties which may result from its use. No
license is granted by implication or otherwise under any patents or other rights of the third parties. Then, we assume
no responsibility whatsoever for any damages resulting from that infringements.
4. The constant of each circuit shown in this document is described as an example, and it is not guaranteed about its
value of the mass production products.
5. In the case of that the Products in this document falls under the foreign exchange and foreign trade control law orother applicable laws and regulations, approval of the export to be based on those laws and regulations are necessary.
Customers are requested appropriately take steps to obtain required permissions or approvals from appropriate
government agencies.
6. When exporting customer’s products that use the Products, customers must comply with the "Foreign Exchange andForeign Trade Act" and other export-related laws and regulations, and follow the necessary procedures inaccordance with those laws and regulations. Do not use the Products in equipment whose sale is prohibited byexport-related laws and regulations ("JP Foreign Exchange and Foreign Trade Act" and "US Export Administration
Regulations", etc.). In addition, please do not sell the Products to users who are expected to use it for the above
equipment or companies in its supply chain. If a user who uses module parts and equipment using the Products is acompany suspected of violating human rights, please do not sell the above parts and equipment to that user.

SEIKO NPC CORPORATION
2-9-4, Taito, Taito-ku,
Tokyo 110-0016, Japan
Telephone: +81-3-6747-5300
Facsimile: +81-3-6747-5303
https://www.npc.co.jp/
Email:sales@npc.co.jp

SMD-01B Data Sheet
DE220191-E001

2024.08
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