features ? small size ? low cost ? multiple mounting options ? wide resolution range ? linear and rotary options available ? no signal adjustment required ? insensitive to radial and axial play ? -40c to +85c operating temperature ? two channel quadrature output ? ttl compatible ? single 5v supply ? wave solderable description the heds-9700 series is a high performance, low cost, optical incremental encoder module. when operated in conjunction with either a codewheel or codestrip, this module detects rotary or linear position. the 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 photo - detector array, the module is extremely tolerant to mounting misalignment. the two channel digital outputs and 5v supply input are accessed through four solder-plated leads located on 2.54 mm (0.1 inch) centers. the standard heds-9700 is designed for use with an 11 mm optical radius codewheel, or linear codestrip. other options are available. please contact factory for more in - formation. mounting option #50 - standard (baseplane mounting) contact factory for detailed pack age dimensions esd warning; normal handling precautions should be taken to avoid static discharge. heds-970x, heds-972x series digital output small optical encoder modules data sheet package dimensions
2 applications the heds-9700 provides sophisticated motion detection at a low cost, mak ing closed-loop control very cost-com - petitivef typical applications include printers, plotters, copiers, and ofce automation equipment. note: avago technologies encoders are not recom - mended for use in safety critical applications. eg. abs bra k ing systems, power steering, life support systems and critical care medical equipment. please contact sales representative if more clarifcation is needed. theory of operation the heds-9700 is a c-shaped emitter/detector module. coupled with a codewheel, it translates rotary motion into a two-channel digital output. coupled with a codestrip, it translates linear motion into a digital output. as seen in the block diagram, 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 digital waveforms. 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 cod ewheel/ codestrip. the photodiodes which detect these interrup - tions 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 dar k period on the adjacent pair of detectors. the photodiode outputs are fed through the signal processing circuitry. two comparators receive these signals and produce the fnal outputs for channels a and b. due to this integrated phasing technique, the digital output of channel a is in quadrature with channel b (90 degrees out of phase). block diagram
pulse width (p): the number of electrical degrees that an output is high during one cycle. this value is nomi - nally 180e or 1/2 cycle. pulse width error ( ? p): the deviation, in electrical de - grees, of the pulse width from its ideal value of 180e. state width (s): the number of electrical degrees be - tween 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 90e. state width error ( ? s): the deviation, in electrical de - grees, of each state width from its ideal value of 90e. phase ( ): 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 90e for quadrature output. phase error ( ? ): the deviation of the phase from its ideal value of 90e. direction of rotation: when the codewheel rotates counterclockwise, as viewed look ing down on the mod - ule (so the mar k ing is visible), channel a will lead chan - nel b. if the codewheel rotates in the opposite direction, channel b will lead channel a. optical radius (rop): the distance from the codewheels center of rotation to the optical center (o.c.) of the encoder module. absolute maximum ratings parameter symbol min. max. units notes storage temperature t s -40 85 c see note operating temperature t a -40 85 c see note supply voltage v cc -0.5 7 v output voltage v o -0.5 v cc v output current per i o -1.0 5 ma channel soldering temperature 260 c t 5 sec. output waveforms defnitions 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). 1 shaft rotation = 60 mechanical degrees = n cycles 1 cycle (c) = 60 electrical degrees (e) = 1 bar and window pair
4 encoding characteristics encoding characteristics over recommended operating range and recommended mounting tolerances. these characteristics do not include codewheel/codestrip contributions. case 1 case 2 parameter symbol typ. max. max. units notes pulse width error ? p 7 0 40 e logic state width error ? s 5 0 40 e phase error ? 2 10 15 e case 1: module mounted on tolerances of 0.1 mm (0.005). case 2: module mounted on tolerances of 0.25 mm (0.010) note: see figures in mounting considerations for details on case 1 and case 2 mounting tolerances. recommended operating conditions parameter symbol min. max. units notes temperature ?40 85 c supply voltage v cc 4.5 5.5 v ripple < 100 mv p-p load capacitance c l 100 pf .2 k ? pull-up count frequency 20 k hz (velocity (rpm) x n)/60 note: the module performance is guaranteed to 20 k hz but can operate at higher frequencies. for operation at 0khz for resolution options e, f, g and h, the maximum pulse width and logic state width errors are 40e and phase error is 15e. electrical characteristics electrical characteristics over recommended operating range, typical at 25c. parameter symbol min. typ. max. units notes supply current i cc 17 40 ma high level output voltage v oh 2.4 v i oh = -40 a low level output voltage v ol 0.4 v i ol = .2 ma rise time t r 200 ns c l = 25 pf, r l = 11 k ? fall time t f 50 ns c l = 25 pf, r l = 11 k ?
5 recommended codewheel and codestrip characteristics mounting option #51 C rounded outline (baseplane mounting) parameter symbol min. max. units notes window/bar ratio ww/wb 0.7 1.4 window length (rotary) lw 1.80 2. 0 mm (0.071) (0.091) (inch) absolute maximum codewheel rc rop + .40 mm includes eccenC radius (rotary) (rop + 0.1 4) (inch) tricity errors center of post to inside w1 1.04 mm edge of window (0.041) (inch) center of post to outside w2 0.76 mm edge of window (0.0 0) (inch) center of post to inside edge l .60 mm of codestrip (0.142) (inch) optional packages available
6 optional packages available (contd.) mounting option #52 C backplane (backplane mounting) mounting option #53 C standard with posts (baseplane mounting)
7 optional packages available (contd.) mounting option #54 C tabless (baseplane mounting) mounting option #55 C backplane with posts (backplane mounting)
8 bent lead option note: these dimensions include shaft end play and codewheel warp. all dimensions for mounting the module and codewheel/codestrip should be measured with respect to the two mounting posts, shown above. mounting tolerances case 1 and case 2 specify the mounting tolerances required on rm in order to achieve the respective encoding characteristics shown on page 4. the mounting tolerances are as follows: case 1: rm 0.1 mm (.005 inches) case 2: rm 0.25 mm (.010 inches) recommended screw size: m2.5 x 0.45 or 2-56 mounting considerations
9 recommended wave solder conditions flux C rma water soluble (per mil-f-14256d) process parameters 1. flux 2. pre-heat 60 seconds total nominal preheat temp: 90c min: 85c max: 110c . solder pot zone nominal dip in time: 2.5 - 4.5 seconds min: 2.5 seconds max: 5 seconds pcb top side: 140 -160c pcb bottom side: 240 - 260c 4. wave solder 255c, 1.2 meters/minute line speed 5. hot water wash 1st: 0c 45 seconds 2nd: 70c 90 seconds 6. rinse 1st: 2c 45 seconds 2nd: 2c 45 seconds 7. dry 1st: 80c 105 seconds 2nd: 95c 105 seconds typical interface host processor ch b ch a hedsC9700 avago hctl-20xx quadrature decoder/ counter
ordering information note: please contact factory for codewheel and codestrip information. 50 51 52 5 54 55 heds-9700 k c * d * * e * f * * * * g h * * * * l m p heds-9701 k c * * d e * * f * * g h * * * l m p 50 51 52 5 54 55 heds-9720 k c d e f g h l * * * m p * * * * * heds-9721 k c d e f g h l * m p * * * 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. obsoletes 5988-8045en av02-0511en - june 13, 2007 heds-97 resolution options (11 mm optical radius, rop) k C 96 cpr c C 100 cpr d C 192 cpr e C 200 cpr f C 256 cpr g C 60 cpr h C 400 cpr (linear) l C 120 lpi m C 127 lpi p C 150 lpi lead bend 0 C straight leads 1 C bent leads 0 C rotary 2 C linear mounting options 50 C standard 51 C rounded outline 52 C back plane 5 C standard w/posts 54 C tabless 55 C back plane w/posts contact factory for other resolution options option
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