AEDR-8710-102

Data Sheet AEDR-871x 3-Channel High Resolution Reflective Incremental Encoder (Digital Outputs) Description The Broadcom® AEDR-871x encoder is the smallest 3-channel optical encoder with digital outputs that employs Reflective Technology for motion control. The encoder is designed to operate over the –40°C to 85°C temperature range and so is suitable for both commercial and industrial applications. AEDR-871x offers high resolution (318 LPI) with built-in interpolation, enabling great flexibility and versatility in resolution range. The compact dimensions of 3.95 mm (L) × 3.4 mm (W) × 0.9562 mm (H) coupled with the low operating 3.3V option allows it to be used in a wide range of miniature commercial applications and portable devices in which space and power consumption is a primary concern. Features        Applications  AEDR-871x encoder offers two-channel (AB) quadrature digital outputs and a third channel, index digital outputs. Being TTL compatible, the outputs of the AEDR-871x encoder can be interfaced directly with most of the signal processing circuitries. Therefore, the encoder provides great design-in flexibility and easy integration into existing systems.         Broadcom World's smallest 3-channel reflective technology encoder Digital Output option – 3 channels TTL compatible; 2 channel quadrature (AB) digital outputs for direction sensing and a third channel, Index digital output. Built-in interpolator for 4×, 8×, and 16× interpolation. Surface mount leadless package 3.95 mm (L) × 3.4 mm (W) × 0.9562 mm (H) Operating voltage of 3.3V or 5V supply Built-in LED current regulation, removing the need for external biasing resistor –40 °C to 85 °C absolute operating temperature Encoding resolution: 318 (lines/inch, LPI) Ideal for high volume applications: Miniature motors Printers and copiers Card readers Miniature camera module Portable measurement devices Healthcare, lab diagnostic equipment and portable devices Optometric equipment Consumer and industrial product applications AV02-4517EN November 30, 2017 AEDR-871x Data Sheet 3-Channel High Resolution Reflective Incremental Encoder (Digital Outputs) Output Waveform Top View P C 360 e Deg A Amplitude I S1 B S2 S3 S4 Anti-clockwise Po Index of 90 e Deg option I Encoder CH A leads CH B Po Index of 180 e Deg option I Po Codewheel Index of 360 e Deg option I Codewheel rotation movement (Anti-clockwise) Note: Drawing not to scale QUADRATURE SIGNALS A, B and I Test Parameter Definitions Parameter Symbol Description 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. C An indication of cycle uniformity. The difference between an observed shaft angle that gives rise to one electrical cycle, and the nominal angular increment of 1/N of a revolution. Pulse Width (Duty) 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 (Duty) Error P The deviation, in electrical degrees, of the pulse width from its ideal value of 180°e. State S The number of electrical degrees between a transition in the output of channel A and the neighboring transition in the output of channel B. There are 4 states per cycle, each nominally 90°e. State Error S The deviation, in electrical degrees, of each state width from its ideal value of 90°e. One Shaft Rotation Cycle Error Phase Phase Error 360 mechanical degrees, N cycles. ɸ ɸ 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. The deviation of the phase from its ideal value of 90°e. Optical Radius ROP The distance from the codewheel’s center of rotation to the optical center (O.C.) of the encoder module. Index Pulse Width PO The number of electrical degrees that an index is high during one full shaft rotation. Broadcom AV02-4517EN 2 AEDR-871x Data Sheet 3-Channel High Resolution Reflective Incremental Encoder (Digital Outputs) Absolute Maximum Ratings Parameter Value Storage Temperature, TS –40°C to 85°C Operating Temperature, TA –40°C to 85°C Supply Voltage, VCC 7V NOTE: 1. Exposure to extreme light intensity (such as from flashbulbs or spotlights) may cause permanent damage to the device. 2. Proper operation of the encoder cannot be guaranteed if the maximum ratings are exceeded. ATTENTION: To avoid damage or degradation induced by ESD, take normal static precautions when handling the encoder. Recommended Operating Conditions Parameter Symbol Min. Typ. Max. Units TA –40 25 85 °C VCC 3.0 3.3 3.6 V 4.5 5 5.5 ICC — 27 60 mA F — — 240 kHz 4× Interpolation F — — 480 kHz 8× Interpolation F — — 960 kHz 16× Interpolation Radial Misalignment ER — — ± 0.2 mm Tangential Misalignment ET — — ± 0.2 mm Codewheel Gap G 0.5 0.75 1.0 mm Operating Temperature Supply Voltage Current Output Frequency Notes Ripple < 100 mVp-p Recommended Codewheel Characteristics Parameter Symbol Min. Max. WW/WB 0.9 1.1 Window/Bar Length LW 1.80 (0.071) — Specular Reflectance Rf 60 — Reflective areaa — 10 Non-reflective area LPmm 12.52 lines/mm LPI 318 lines/inch Window/Bar Ratio Line Density b Unit Notes mm (inches) a. Measurements from TMA µScan meter b. LPmm = CPR/[2π.Rop(mm)]. Broadcom AV02-4517EN 3 AEDR-871x Data Sheet 3-Channel High Resolution Reflective Incremental Encoder (Digital Outputs) Encoder Pinouts VDDD VDDA VDDA CH A AGND VDDD CH A AGND DGND DGND CH B SEL 1 CH I SEL 1 CH B SEL 2 Pin Configurations (Top View) SEL 2 CH I Pin Configurations (Bottom View) Digital Option – Encoder's Built-in Interpolation Pin (Interpolation) SEL 1 SEL 2 Interpolation Factor Max. Output Frequency Example of CPR @ ROP = 11 mm Ha Ha 4´ 240 kHz 3460 Lb Lb 8´ 480 kHz 6920 Ha Lb 16´ 960 kHz 13840 a. HIGH Logic Level. b. LOW Logic Level. This interpolation factor may be used with the following formula to cater to the need for various rotation speeds (RPM) and counts. RPM = (Count Frequency × 60 ) / CPR The CPR (@1´ interpolation) is based on the following formula, which is directly dependent on ROP: CPR = LPI × 2π × ROP (inch) or CPR = LPmm × 2π × ROP (mm) NOTE: Broadcom LPmm (lines per mm) = LPI/25.4. AV02-4517EN 4 AEDR-871x Data Sheet 3-Channel High Resolution Reflective Incremental Encoder (Digital Outputs) Recommended Setup For the Power Supply Pins Connect both VDDD, VDDA and their corresponding grounds (AGND and DGND) appropriately as follows. It is recommended that you use 22 µF and 0.1 µF for bypass capacitor on VDDD and VDDA and place them in parallel as close as possible to the power and the ground pins. VCC 0.1 PF 22 PF 9 DGND 6 0.1 PF 1 VDDA CH A AGND CH B SEL1X CH I 5 SEL2X 4 SEL2X CH B 7 8 VDDD CH I CH A 22 PF 2 3 SEL1X NOTE: 1. DGND (Pin 9) is the center pad of the package. 2. For SEL1X and SEL2X configuration, see the Digital Option – Encoder's Built-in Interpolation table. Broadcom AV02-4517EN 5 AEDR-871x Data Sheet 3-Channel High Resolution Reflective Incremental Encoder (Digital Outputs) Encoding Characteristics (Codewheel of ROP @ 11 mm) Dynamic Performance Parameter Symbol Typical Interpolation Factor Unit 4× 8× 16× C ±17 ±28 ±35 °e Pulse Width (Duty) Error P ±14 ±18 ±22 °e Phase Error  ±5 ±8 ±9 °e State Error S ±8 ±10 ±13 °e Cycle Error Index Pulse Width (Gated 90°) Po 90 90 90 °e Index Pulse Width (Gated 180°) Po 180 180 180 °e Index Pulse Width (Gated 360°) Po 360 360 360 °e NOTE: 1. Typical values represent the average values of encoder performance in our factory-based setup conditions. 2. The optimal performance of the encoder depends on the motor/system setup condition of the individual customer. Electrical Characteristics Characteristics over recommended operating conditions at 25°C. Parameter Symbol Min. Typ. Max. Unit High Level Output Voltage VOH 2.4 — — V IOH = –4 mA Low Level Output Voltage VOL — — 0.4 V IOH = +4 mA Output current per channel, lout lo — — 4 mA Rise Time tr — < 100 — ns Fall Time tf — < 100 — ns Broadcom Notes CL ≤ 50 pF AV02-4517EN 6 AEDR-871x Data Sheet 3-Channel High Resolution Reflective Incremental Encoder (Digital Outputs) Codewheel Design Guideline The index bar (I-) track is opaque and the width is 3 × WB°. The Index (I) track is reflective and the width is 3 × WW°. The dimension LW should be at least 1.8 mm. (Note: If LW shorter than 1.8 mm is required, consult the factory). There are six pairs of incremental track (1 pair= 1 WB° and 1 WW°) between opaque and reflective index tracks. Figure 1: Codewheel Design Example WWq WBq Opaque Surface 3×WBq (Index Bar Track) 6×(WWq+WBq) Reflective Surface LW 3×WWq (Index Track) The following demonstrates a codewheel design for Rop of 11 mm @ 865 CPR for a 2-channel and a 3-channel encoder. Figure 2: Codewheel Pattern for a 2-Channel Encoder Reflective Surface 0.4162q 0.2081q Opaque Surface 865CPR Broadcom Pitch= 360/CPR=360/865=0.4162° WW° and WB° = 360/(2×CPR) = 360/(2×865)=0.2081° AV02-4517EN 7 AEDR-871x Data Sheet 3-Channel High Resolution Reflective Incremental Encoder (Digital Outputs) Figure 3: Codewheel Pattern for a 3-Channel Encoder 1.8 0.4162q 0.2081q 0.2081q 0.6243q Opaque Surface 2.4971q Reflective Surface 0.6243q WW° and WB° = 360/(2×CPR) = 360/(2×865)=0.2081° Index Width = 3×WW° = 0.6243° Index Bar Width = 3×WB° = 0.6243° NOTE: The overall physical track count is reduced but not the counts per revolution (CPR). The CPR remains the same because the count during this index transition is generated by an intelligent signal processing circuit. Package Outline Drawing 0.9562 Note: Unless otherwise specified, 1. All dimensions in mm. 2. Tolerance x.xx ± 0.15 mm. TOP VIEW 3.40±0.20 0.50 Center of Lens 8×0.350 2×0.90 3.95±0.20 2.15 2×0.90 2.62 8×0.450 2×0.95 FRONT VIEW Broadcom 2×0.95 BACK VIEW AV02-4517EN 8 AEDR-871x Data Sheet 3-Channel High Resolution Reflective Incremental Encoder (Digital Outputs) Recommended Land Pattern 3.40 0.5 2×3.00 Package outline 2.15 2×1.8 8 ×0.35 3.95 8 ×0.80 2×1.9 2×2.45 Broadcom All dimensions in mm Tolerance x.xx ± 0.05 mm AV02-4517EN 9 AEDR-871x Data Sheet 3-Channel High Resolution Reflective Incremental Encoder (Digital Outputs) Encoder Placement Orientation and Positioning The AEDR-871x is designed such that both the emitter and the detector ICs are placed parallel to the window/bar orientation, with the encoder mounted on top of the codewheel (see below right). When properly oriented, the detector side will be closer to the center of codewheel than the emitter. More importantly, the center of the lens of the encoder unit must be aligned with the codewheel (ROP), or more specifically tangential to the center point of LW (1/2 of the length of the window). Codewheel Codewheel Emitter (LED) Placement orientation of the encoder’s emitter and detector on the codewheel 2.62 Detector Center of Codewheel Center of the lens should be aligned with the ROP of the codewheel Broadcom AV02-4517EN 10 AEDR-871x Data Sheet 3-Channel High Resolution Reflective Incremental Encoder (Digital Outputs) Direction of Movement With the detector side of the encoder placed closer to the codewheel (see the figure on the previous page), Channel A leads Channel B when the codewheel rotates anti-clockwise and vice versa (with the encoder mounted on top of the codewheel). The optimal gap setting recommended is between 0.5 mm to 1.0 mm (see the side view below). Encoder height = 0.9562 mm Gap = 0.5 to 1.0 mm Codewheel Side View Codewheel CH A leads CH B Codewheel CH B leads CH A Top View Anti-clockwise Emitter Clockwise Emitter Note: Drawing not to scale Moisture Sensitivity Level The AEDR-871x is specified to Moisture Sensitive Level (MSL) 3. Precaution is required to handle this moisture-sensitive product to ensure the reliability of the product. Storage before use:   An unopened moisture barrier bag (MBB) can be stored at < 40°C/90% RH for 12 months. It is not recommended that the MBB is opened before assembly. Control after the MBB is opened:  Encoder that will be subjected to reflow solder must be mounted within 168 hours of factory condition 10% when read at 23°C ± 5°C. The encoder floor life exceeded 168 hours. Recommended baking condition: 60°C ± 5°C for 20 hours (tape and reel), 125°C ± 5°C for 5 hours (loose unit). Broadcom AV02-4517EN 11 AEDR-871x Data Sheet 3-Channel High Resolution Reflective Incremental Encoder (Digital Outputs) Recommended Lead-free Reflow Soldering Temperature Profile 250 Max. 235 qC Liquidus point 217 qC 200 150 60 sec Max. 100 Preheat Zone 50 0 0 25 50 60 75 100 125 150 175 200 225 250 275 300 324 354 Thermocouple Mold Compound LED IC Reflow PCB Average ramp up rate = 3°C/s Average ramp down rate = 6°C/s Preheat temperature = 150°C to 200°C Preheat time = 60s to 100s Time maintain above 217°C = 40s to 60s Peak temperature = 235°C Time within 5°C of peak temperature = 20s to 30s NOTE: 1. Reflow with peak temperature > 235°C may damage the component. 2. Due to treatment of high temperature, this clear compound may turn yellow after IR reflow. 3. Profile shown here is the actual readings from the thermocouple (attached to AEDR-871x as shown above) on the reflow board PCB. Broadcom AV02-4517EN 12 AEDR-871x Data Sheet 3-Channel High Resolution Reflective Incremental Encoder (Digital Outputs) Tape and Reel Information Order Information AEDR – 87xx – x 0 x Output Signal Index Gating Packaging Resolution LPI Shipping Units 1 – Digital 2 – Analog 0 – Gated 90ºe 1 – Gated 180ºe 2 – Gated 360ºe 3* – Tag 360ºe 1 – Tape and Reel 0 – 318 0 – 1000 pcs 2 – 100 pcs Broadcom Notes: Digital 3.3V and 5V operating mode Analog: 5V operating mode only Index Gating: 3* applicable only for analog output AV02-4517EN 13 Disclaimer Broadcom’s products and software are not specifically designed, manufactured, or authorized for sale as parts, components, or assemblies for the planning, construction, maintenenace, or direct operation of a nuclear facility or for use in medical devices or applications. 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