HEDS-97EX Series Small Optical Encoder Modules 200 LPI Analog Voltage Output Data Sheet Description Features The HEDS-97EX series is a small and high performance optical incremental encoder module. When operated in conjunction with either a codewheel or codestrip, this module detects rotary or linear position. The encoder module consists of a lensed LED source and a detector IC enclosed in a small C-shaped plastic package. Due to a highly collimated light source and a unique photodetector array, the module is extremely tolerant to mounting misalignment. • Small size The two channel analog outputs and 3.3V supply input are accessed through four solder-plated leads located on 2.54 mm (0.1 inch.) centers. • RoHS compliant HEDS-97EX is designed for use with an appropriate optical radius codewheel. Please contact factory for more information. • Multiple mounting options • Insensitive to radial and axial play • 0°C to +60°C recommended operating temperature • Two channel analog output • Single 3.3V supply • Wave solderable Specifications • 200 LPI • 3.3V supply* * Typical conditions Applications • Printers • Copiers/Fax • Plotters • Office automation equipments ESD WARNING: NORMAL PRECAUTIONS SHOULD BE TAKEN TO AVOID STATIC DISCHARGE. Theory of Operation Definitions The HEDS-97EX is a C-shaped emitter/detector module. Coupled with a codewheel/codestrip, it translates rotary motion into a two-channel analog output. Count (N): The number of bar and window pairs or counts per revolution (CPR) of the codewheel. Or the number of lines per inch of the codestrip (LPI) The module contains a single Light Emitting Diode (LED) as its light source. The light is collimated into a parallel beam by means of a single 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 analog waveforms. 1 shaft rotation = 360 degrees = N cycles The codewheel/codestrip moves between the emitter and detector, causing the light beam to be interrupted by the pattern of spaces and bars on the codewheel/ codestrip. The photodiodes, which detect these interruptions, are arranged in a pattern that corresponds to the radius and count density of the codewheel/codestrip. These detectors are also spaced such that a light period on one pair of detectors corresponds to a dark period on the adjacent pairs of detectors. The photodiode outputs are fed through the signal processing circuitry, which produce the final outputs for Channel A and Channel B. Due to this integrated phasing technique, the analog output of Channel A is in quadrature with Channel B (90 degrees out of phase). 1 cycle (c) = 360 electrical degree, equivalent to 1 bar and window pair. 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. Line Density: The number of window and bar pair per unit length, express in either lines per inch (LPI) or lines per mm (LPmm) Optical Radius (Rop): The distance from the codewheel’s center of rotation to the optical center (O.C) of the encoder module. Gap (G): The distance from surface of the encoder to the surface of codewheel or codestrip Mounting Position (RM): Distance from Motor Shaft center of rotation to center of Alignment Tab receiving hole. Radial and Tangential Misalignment Error (ER and Er): For rotary motion mechanical displacement in the radial and tangential directions relative to the nominal alignment Angular Misalignment Error (EA): Angular misalignment of the sensor in relation to then tangential direction. This applies for both rotary and linear motion.of electrical degrees that an output is high during one cycle, nominally 180°e or 1/2 a cycle. Absolute Maximum Ratings Subjecting the part to stresses beyond those listed under this section may cause permanent damage to the device. These are stress ratings only and do not imply that the device functions beyond these ratings. Exposure to the extremes of these conditions for extended periods may affect device reliability. Parameter Symbol Min. Max. Units Storage Temperature TS -40 85 °C Operating Temperature TA 0 60 °C Supply voltage (Detector) VCC -0.5 7 V Output Voltage Va , Vb -0.5 VCC + 0.4 V 260 °C t ≤ 7 sec Soldering Temperature Notes DC Forward current (LED) ILED 50 mA VF < 1.8V Reverse Voltage VR 5 V IR = 100uA Recommended Operating Conditions Parameter Symbol Min. Typ. Max. Units Operating Temperature T 0 25 60 °C Supply Voltage (Detector) VCC 3.15 3.3 3.45 V Ripple < 100mVpp Output Frequency f 8 40 KHz (Velocity (rpm) x N)/60 DC Forward Current (LED) ILED 26 Notes mA Electrical Characteristics Electrical Characteristics over Recommended Operating Range, typically at 25°C Parameter Symbol Supply Current (Detector) ICC LED Forward Voltage VF Min. 1.3 (turn on) 1.5 (operate) Typ. Max. Units 5 8 mA 1.44 1.54 V Notes Typical If = 24mA Encoding Characteristics Parameter Symbol Min (b) Max (b) Units State width error DS -40 +40 °e Pulse width error DP -40 +40 °e Peak to Peak voltage VppA VppB 1 3 V Analog offset voltage Voffset A Voffset B -150 150 mV Notes: (a) Obtained at typical conditions specified in “Recommended Operating Conditions” and nominal mounting position (Radial, Tangential, Gap) of (0,0, 0) (b) Obtained over the whole “Recommended Operating Conditions” and “Part Mounting Tolerances” Waveform Definition Ch A Vpp 1.65 voltage offset reference Ch B PA PB S1 S2 S3 S4 Test Parameter Definitions Parameter Symbol Definition Units Analog peak voltage Vap, Vbp, Vam, Vbm The absolute value in V of the magnitude of the analog signal (i.e. one sided rating) V Analog peak to peak voltage Vpp The peak to peak signal magnitude in mA of the analog signal V Analog peak to peak ratio VppA/VppB The ratio of A channel peak analog signal to B channel peak analog signal V Analog Crossing Vx12, Vx34, Vx56, Vx78 The intersection in V of the A channel analog waveform with either the B channel analog V waveform or its compliment. Analog Offset current Voffset The offset in V from the mid-point of the analog peak to peak signal to zero current State Width S1, S2, S3, S4 The number of electrical degrees between a transition in channel A and the neighboring °e transition in channel B. There are 4 state per cycle, each nominally 90°e. The transitions are determined by where the analog signal crosses the Zero point State Width Error DS1, DS2, DS3, DS4 The deviation in electrical degrees of each state width from its ideal value of 90°e. °e Pulse Width PA,PB The number of electrical degrees that an analog output is greater than zero during one cycle. This value is nominally 180°e or ½ cycle. °e Pulse Width Error DP The deviation in electrical degrees of each pulse width from its ideal value of 180°e. °e V Mounting Configuration Error Rop=19.40mm Unit Notes Recommend CW to put closer to the detector side (upper side), in order to give enough margin for encoder operation. Eg Gap 0.05 to 0.65 mm Er Radial ±0.13 mm Et Tangential ±0.13 mm Ea Angular ±3 Deg. 4.25 ± 0.3 (0.17 ± 0.012) 5.32 MAX. (0.2094) SEE NOTE 1 Rm CL OF ALIGNMENT TAB Rop 6.30 MAX. (0.248) 6.50 MIN. (0.256) 2.03 MIN. (0.080) 1.0 DEEP MIN. (0.039) 2X R Rm = Rop - 0.14 (0.006) ∅ 2.03 HOLE MIN. (0.080) NOTE: THESE DIMENSIONS INCLUDE SHAFT END PLAY AND CODEWHEEL WARP. ALL DIMENSIONS FOR MOUNTING THE MODULE/CODESTRIP SHOULD BE MEASURED WITH RESPECT TO THE TWO MOUNTING POSTS, SHOWN ABOVE. DIMENSIONS IN MILLIMETERS (INCHES). 1.0 DEEP MIN. (0.039) Recommended Codewheel and Codestrip Characteristics MAX 3.4 (0.134) Wb Ww Lw Rc Rop W1 W2 Ww Wb Parameter Symbol Min. Max. Window/Bar Ratio Ww/Wb 0.9 1.1 Window Length (Rotary) Lw 1.80 (0.071) 3.0 (0.1181) mm (inch) Absolute Maximum Codewheel Radius (Rotary) Rc Rop + 3.40 (Rop + 0.134) mm (inch) Center of Post to Inside Edge of Window W1 1.04 (0.041) mm (inch) Center of Post to Outside Edge of Window W2 0.76 (0.030) mm (inch) Center of Post to Inside Edge of Codestrip L 3.60 (0.142) Units mm (inch) Notes Includes eccentricity errors Package Dimensions HEDS-97E0-R50 (Bracket 50) 1.4 0.055 2x ∅ 7.5 0.295 2.00 0.079 15.0 0.591 10.1 0.398 3.0 0.118 0.8 0.031 20.2 0.795 10.8 0.425 9.8 0.386 4.2 0.167 1.7 0.667 3.9 0.154 YYWW 3.9 0.152 0.14 0.006 7.0 0.276 50 5.0 0.198 97EX 6.4 0.252 GND R 1.4 0.055 5.5 0.217 LEAD THICKNESS: 0.25 0.010 VCC CH A 0.50 0.020 (OPTICAL CENTER) CH B 3.8 0.150 1.8 0.071 12.6 0.496 HEDS-97E0-R54 (Bracket 54) (OPTICAL CENTER) 97EX 6.4 0.252 3.9 0.152 0.14 0.006 2x ∅ YYWW 54 5.5 0.217 4.9 0.193 2.00 0.079 3.0 0.118 9.8 0.386 10.8 0.425 0.8 0.031 4.2 0.167 1.7 0.667 3.9 0.154 HEDS-97E1-R54 (BEND LEAD) 3.0 0.118 5° TYP 9.2 0.362 3.8 0.150 0.50 0.020 0.25 0.010 GND CH B 0.50 0.020 VCC CH A LEAD THICKNESS: 3.8 0.150 12.6 0.496 Recommended Wave Solder Profile 7 sec Max 260ºC Temperature (ºC) A B C Reflow 120ºC/120 sec Max Cool Down Time (s) Parameter Min. Max. Nominal values Units A Solder Pot Temperature NA 260 250 - 260 °C B Preheat Zone Temperature 85 120 100 - 120 °C C Dip in Time 5 7 5 sec D Solder Pot Zone (Encoder Lead) 200 260 NA °C Note: - Nominal values are evaluated profiles for optimum performance. - Min/Max are critical limits to ensure encoders in good condition. Ordering Information HEDS-97E Option Lead Configuration 0 - Straight Leads 1 - Bent Leads Resolution Option R - 200 LPI Bracket Option 50 54 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 © 2006 Avago Technologies Limited. All rights reserved. AV02-0184EN - March 28, 2007