SMD-01 NPC | Alldatasheet
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Technical content
SEIKO NPC CORPORATION —1 Optical Encoder Head OVERVIEW The SMD-01 is a high-precision optical encoder 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 from the 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-01 and the scale. In addition, the light receiver employs a photodiode array to reduce the degradation in phase characteristics due to dependency on mounting position error, making the SMD-01 easier to mount.
FEATURES
I Package: Miniature clear-mold package (5.3 4.3 1.68mm) I Output signal period: 20 µ m (Uses 20 µ m period A-phase/B-phase signals to achieve 5 µ m resolution) I Optimized OEIC and optics design for easy mounting alignment I LED and OEIC fabricated in a single package I Adjustable LED brightness using external inputs I Analog (sine wave) output I Supply voltage: 3.13 to 5.25V I Current consumption: 12.2mA (typ)
APPLICATIONS
I Linear motors I Precision stages I Sliders I Mounting equipment I Robots I Angle measurement equipment I Various encoder devices PINOUT (Top view) PACKAGE DIMENSIONS (Unit: mm) SWL1 SWL2 VCC NC NC NC SWV GND NC VA VAB VB VBB VREF LED Side view 2 Side view 1 Bottom view Slit Gold (Au) electrodes Epoxy resin Glass-epoxy substrate Top view Head center OEIC 5.3 ± 0.1 0.4 ± 0.1 0.3 ± 0.075 4.3 ± 0.1 1.68 ± 0.15 (0.3) 0.6 14 − R0.15
SEIKO NPC CORPORATION —2 BLOCK DIAGRAM PIN DESCRIPTION Number Name I/O *1. Ip: input with built-in pull-up resistor
Description
1 SWL1 Ip LED brightness adjustment 1
2 SWL2 Ip LED brightness adjustment 2
3 VCC – Supply voltage (+)
4 NC – No connection (leave open circuit)
5 NC – No connection (leave open circuit)
6 NC – No connection (leave open circuit)
7 SWV Ip
Reference voltage (VREF) select input HIGH: VREF = 1.45V (typ) LOW: VREF = 2.25V (typ)
8 VREF O Reference voltage output
9 VBB O B-phase inverted analog signal (BB phase) output
10 VB O B-phase analog signal output
11 VAB O A-phase inverted analog signal (AB phase) output
12 VA O A-phase analog signal output
13 NC – No connection (leave open circuit)
14 GND – Ground
SEIKO NPC CORPORATION —3 SPECIFICATIONS Absolute Maximum Ratings Note. Condensation free Recommended Operating Conditions Note. Since it may influence the reliability if it is used out of range of recommended operating conditions, this product should be used within this range. Condensation free Parameter Symbol Rating Unit Supply voltage *1. This parameter rating is the values that must never exceed even for a moment. The device may be damaged or deteriorated the characteristics or reliability if this parameter rating is exceeded. V CC 0.3 to +5.5 V Storage temperature *2. The device may be deteriorated the characteristics or reliability if this parameter rating is exceeded. T STG 40 to +80 C Parameter Symbol Rating Unit Supply voltage V CC 3.13 to 5.25 V Operating temperature Ta –20 to +60 C Response speed Rt 0 to 2 m/s
SEIKO NPC CORPORATION —4
Electrical Characteristics
V CC 5V , Ta C, unless otherwise noted. I Standard Scale Conditions Electrical characteristics ratings apply under the following conditions: Parameter Pins Symbol Condition Rating Unit min typ max Current consumption 1 VCC I CC1 SWL1 = HIGH, SWL2 = HIGH 4.0 12.2 23.0 mA Current consumption 2 I CC2 SWL1 = HIGH, SWL2 = LOW 7.0 16.9 30.0 mA Current consumption 3 I CC3 SWL1 = LOW, SWL2 = HIGH 11.0 21.0 35.5 mA Current consumption 4 I CC4 SWL1 = LOW, SWL2 = LOW 2.0 6.0 13.5 mA Reference voltage VREF Vref SWV = HIGH 1.00 1.45 2.00 V SWV = LOW 1.40 2.25 3.20 V A-phase output signal amplitude VA VAP-P Vp-p, SWL1 = HIGH, SWL2 = HIGH, Standard scale conditions 0.13 0.85 3.00 V AB-phase output signal amplitude VAB VABP-P B-phase output signal amplitude VB VBP-P BB-phase output signal amplitude VBB VBBP-P A-phase signal offset voltage VA VAO SWL1 = LOW, SWL2 = LOW, Variation from VREF –0.25 0.00 0.25 V AB-phase signal offset voltage VAB VABO B-phase signal offset voltage VB VBO BB-phase signal offset voltage VBB VBBO A-phase – B-phase difference VA, VB DP Standard scale conditions 50 90 130 Output voltage fluctuation 1 VREF , VA, VAB, VB, VBB VO1 Difference between 0 µ A and 50 µ A sink current 0 – +30 mV Output voltage fluctuation 2 VO2 Difference between 0 µ A and 50 µ A source current –30 – 0 mV HIGH-level input voltage SWL1, SWL2, SWV V IH 0.8V CC CC V LOW-level input voltage V IL 0 – 0.2V CC V Input current Io_SW Input voltage = 0V 1 – 20 µ A (VAO and VBO offsets represent the differences between the VA and VB amplitude center values and Vref.) Parameter Conditions Unit Scale Reflective surface reflection factor 57 % Non-reflective surface reflection factor 5 % Pattern 20 µ m pitch (10 µ m Cr line/10 µ m spacing) – SMD-01 head alignment Gap ( Gap) 0.3 mm Y aw angle ( Roll angle ( Pitch angle ( VAO Vref VAP-P center VBP-P center VAP-P VBP-P VA VB VBO 20µm
The SMD-01 head emits 635nm 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 is focused on a photodiode array to detect the relative movement between the head and the scale. A20μm period pseudo sine wave phase A (V A) signal corresponding to the detector state is output, together with phase B (VB), which has 90°phase difference from V A, and inverted signals of both V A & VB (V AB, VBB). LED Brightness Switching Function The signal amplitude can be adjusted by adjusting the LED brightness. The LED brightness is adjusted by adjusting the LED current. The amplitude adjustment options are shown in the following table. SWL1 H H L L SWL2 H L H L A/B-phase analog signal amplitude ×1.0 ×1.8 ×2.6 ×0 SCALE and HEAD ALIGNMENT The encoder head optical center position is offset from the physical center of the head by 0.77mm (ΔY) in the vertical direction and 0.1mm (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 thorough evaluation 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 is recommended to obtain better product characteristics. Reference data: Parameter Conditions Unit Scale Scale width (±SW) ±1 (min) mm SMD-01 head alignment Scale vertical offset (ΔY) 0.77 mm Scale horizontal offset (ΔX) 0.1 mm Scale Head-scale alignment center Scale width alignment center Head-scale alignment center Yaw angle Roll angle Pitch angle Gap Head center Scale vertical offset (ΔY) Scale horizontal offset (ΔX) Head (SMD-01) Head center ∆θy ∆θr ∆θ ∆Gap +SW -SW
SEIKO NPC CORPORATION —6 Typical Performances by Scale and Head Alignment Amplitude vs. Gap ( Gap) Gap [mm] Amplitude [%] 100 Phase difference vs. Gap ( Gap) Gap [mm] Phase difference [°] Amplitude vs. Yaw angle ( Yaw [°] Amplitude [%] 100 Phase difference vs. Yaw angle ( 0123 4−1−2−3−4 Yaw [°] Phase difference [°] Amplitude vs. Roll angle ( Roll [°] Amplitude [%] 100 Phase difference vs. Roll angle ( Phase difference [°] 0123 4−1−2−3−4 Roll [°]
SEIKO NPC CORPORATION —7 TEMPERATURE and FREQUENCY CHARACTERISTICS Amplitude vs. Pitch angle ( Pitch [°] Amplitude [%] 100 Phase difference vs. Pitch angle ( 0123 4−1−2−3−4 Phase difference [°] Amplitude vs. Temperature (Ta) 02 0−20−40 40 60 Temperature [°C] Amplitude [%] 100 110 120 130 Amplitude vs. Frequency 10 100 1000 Frequency [kHz] Encoder amplitude [dB]
SEIKO NPC CORPORATION —8 PACKAGING The SMD-01 is supplied on trays. The same trays are designed to withstand the baking temperature before reflow, so the devices can be left on the trays during the baking process. Note. The trays can be stacked without problem during baking, but tape and labels must first be removed. Tape Storage quantity: 100pcs (10 × 10) Device Orientation
SEIKO NPC CORPORATION —9 MOUNTING PRECAUTIONS Observe the following precautions when mounting the SMD-01. Soldering Precautions I The SMD devices are hygroscopic (moisture absorbing). If the head is soldered after absorbing moisture, the head plastic may crack and the surfaces between the plastic and other materials may separate. I When soldering, ensure there is no foreign matter adhering to the SMD surface. I After soldering, ensure that no mechanical stress or strong vibration is applied until the devices reach room temperature. Infrared Reflow Method The following temperature profile conditions are recommended when soldering using the application of heat to the entire device. Temperature profile conditions (Package surface temperature) I Before reflow, dry devices at 125 °C ± 5°C for 3 hours, and then reflow in a 30 °C ≤ 70% dehydrated atmo- sphere within 12 hours. Dehydrate devices once only. I Use a Nitrogen atmosphere in the reflow oven. I Reflow devices once only. I Minimize temperatures ripples as much as possible during preheating. I After reflow, the plastic body may be slightly deformed due to heat. Do not touch the devices until they reach room temperature. I The output signal amplitude before and after reflow may vary greatly, depending on the reflow profile condi- tions. 190°C 225°C +1.5 to +5°C/sec 150°C −1.5 to −5°C/sec Preheating 120 sec (max) 40 sec (max) 4°C/sec or less 4°C/sec or less 250°C
SEIKO NPC CORPORATION - 10 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 aerospace equipment, 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 that exerts 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 or reliability 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 or other 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. SEIKO NPC CORPORATION 1-9-9, Hatchobori, Chuo-ku, Tokyo 104-0032, Japan Telephone: +81-3-5541-6501 Facsimile: +81-3-5541-6510 http://www.npc.co.jp/ Email:sales@npc.co.jp NC0906BE 2015.07