1 cs3717a features full/half /quarter step operation output current up to 1 a motor supply voltage 10v to 46v integrated bootstrap lowers saturation voltage built in protection diodes externally selectable current level digital or analog control of output current level thermal overload protection minimum external components package options 1a h-bridge stepper motor driver cs3717a description block diagram 16l pdip (internally fused leads) 1 outb pulse v dd b gnd v cc in1 direction sense outa v dd a gnd gnd v ref comp in in0 gnd december, 2001 - rev. 4 on semiconductor 2000 south county trail, east greenwich, ri 02818 tel: (401)885?600 fax: (401)885?786 n. american technical support: 800-282-9855 web site: www.cherry?emi.com archive device not recommended for new design the cs3717a controls and drives one phase of a bipolar stepper motor with chopper control of the phase current. current levels may be selected in three steps by means of two logic inputs which select one of three current comparators. when both of these inputs are high the device is disabled. a separate logic input controls the direction of cur- rent flow. a monostable, pro- grammed by an external rc net- work, sets the current decay time. the power section is a full h-bridge driver with four internal clamp diodes for current recirculation. an external connection to the lower emitters is available for the insertion of a sensing resistor. two cs3717a? and several external components form a complete stepper motor drive subsystem. the recommended operating ambient temperature range is from 0 to 70?. the cs3717a is supplied in a 16 lead pdip. power supply voltage (v dda , v ddb )............................................................50v logic supply voltage (v cc ) .............................................................................7v logic input voltage (in0, in1, direction) ...............................................6v comparator input............................................................................................v cc reference input voltage..................................................................................15v output current (dc operation)...................................................................1.2a storage temperature .................................................................?5? to +150? operating junction temperature ............................................?0? to +150? lead temperature soldering wave solder(through hole styles only) ...........10 sec. max, 260? peak absolute maximum ratings thermal shutdown v dd a pulse comp in sense outa outb v dd b direction in1 in0 v cc v ref gnd + - + - + - mono- stable 105 ? 223 ? 223 ? 6k ? 00 01 10 11
2 electrical characteristics: refer to the test circuit v dd = 36v, v cc = 5v, t a = 25?; unless otherwise specified. parameter test conditions min typ max unit supply voltage 10 46 v logic supply voltage 4.75 5.25 v logic supply current 7 15 ma reference input current v ref = 5v 0.75 1.00 ma logic inputs input low voltage 0.8 v input high voltage 2 v low voltage input current v in = 0.4v (direction) -100 a (in0, in1) -400 a high voltage input current v in = 2.4v 10 a comparators comparator low v ref = 5v in0 = low 66 80 94 mv threshold voltage in1 = high comparator medium v ref = 5v in0 = high 236 251 266 mv threshold voltage in1 = low comparator high v ref = 5v in0 = low 396 416 436 mv threshold voltage in1 = low comparator input current ?0 a cutoff time r t = 56k ? c t = 820pf 27 37 s turn off delay 2 s output leakage current in0 =in1 = high 100 a source diode-transistor pair saturation voltage i motor = -0.5a conduction period 1.7 2.1 v recirculation period 1.10 1.35 v saturation voltage i motor = -1a conduction period 2.1 2.8 v recirculation period 1.7 2.5 v leakage current v s = 46v 300 a diode forward voltage i motor = -0.5a 1.00 1.25 v i motor = -1a 1.3 1.7 v sink diode-transistor pair saturation voltage i motor = 0.5a 1.20 1.45 v i motor = 1a 1.75 2.30 v leakage current v s = 46v 300 a diode forward voltage i motor = 0.5a 1.1 1.5 v i motor = 1a 1.4 2.0 v cs3717a
3 package pin description package pin # pin symbol function truth table in0 in1 output current h h no current l h low current h l medium current l l high current 16l (internally fused leads) 1 out b output connection with outa. the output stage is a ? bridge formed by four transistors and four diodes suitable for switching applications. 2 pulse a parallel rc network connected to this pin sets the off time of the lower power transistors. the pulse generator is a monos- table triggered by the rising edge of the output of the compara- tors (t off = 0.69 r t c t ). 3v ddb supply voltage input for half output stage. 4, 5, 12, 13 gnd ground connection. also conducts heat from die to printed circuit copper. 6v cc supply voltage input for logic circuitry. 7 in1 this pin and in0 are logic inputs which select the outputs of the three comparators to set the current level. current also depends on the sensing resistor and reference voltage. see truth table. 8 direction this ttl-compatible logic input sets the direction of current flow through the load. a high level causes current to flow from outa (source) to outb (sink). a schmitt trigger on this input provides good noise immunity and a delay circuit prevents out- put stage short circuits during switching. 9 in0 see in1. 10 comp in input connected to the three comparators. the voltage across the sense resistor is fed back to this input through the low pass filter r c c c . the lower power transistors are disabled when the sense voltage exceeds the reference voltage of the selected compara- tor. when this occurs the current decays for a time set by r t c t , t off = 0.69 r t c t . 11 v ref a voltage applied to this pin sets the reference voltage of the three comparators, thus determining the output current (also dependent on r sense and the two inputs in 0 and in 1). 14 v dda supply voltage input for half output stage. 15 out a see outb. 16 sense connection to lower emitters of output stage for insertion of current sense resistor. cs3717a
4 control of the motor the stepper motor can rotate in either direction according to the sequence of the input signals. it is possible to obtain a full step, a half step and quarter step operation. full step operation both windings of the stepper motor are energized all the time with the same current i ma = i mb . in0 and in1 remain fixed at whatever torque value is required. calling the condition with winding a energized in one direction and a in the other direction, the sequence for full step rotation is: ab b aetc. b ab a a typical performance characteristics source saturation voltage vs. output current (conduction period) source saturation voltage vs. output current (recirculation period) 1 2 3 4 v ce sat (v) 0.2 0.4 0.6 0.8 i (a) 0 1 2 3 4 v ce sat (v) 0.2 0.4 0.6 0.8 i (a) 0 comparator threshold vs. junction temperature sink saturation voltage vs. output current 1 2 3 4 v sat (v) 0.2 0.4 0.6 0.8 i (a) 0 v cx (%) 40 160 t j (c) 0 20 40 60 80 100 60 80 100 120 140 20 the application diagram shows a typical application in which two cs3717a's control a two phase bipolar stepper motor. programming the amplitude of the current flowing in the motor wind- ing is controlled by the logic inputs in0 and in1. the truth table (page 3) shows three current levels and an off state. a high level on the ?irection? logic input sets the direction of that current from outa to outb; a low level from outb to outa. it is recommended that unused inputs are tied to v cc or (gnd) as appropriate to avoid noise problems. the current levels can be varied continuously by chang- ing v ref . application information cs3717a
5 for rotation in the other direction the sequence must be reversed. the torque of each step is constant in full step operation. half step operation power is applied alternately to one winding then both according to the sequence: ab b b a a etc. like full step this can be done at any current level; the torque is not constant but is lower when only one wind- ing is energized. a coil is turned off by setting in0 and in1 both high. quarter step operation it is preferable to realize the quarter step operation at full power otherwise the steps will be of very irregular size. b b ab a a the extra quarter steps are added to the half step sequence by putting one coil on half current according to the sequence. ab b b b b etc. motor selection as the cs3717a provides constant current drive with a switching operation, care must be taken to select stepper motors with low hysteresis losses to prevent motor over- heating. l-c filter to reduce emi and chopping losses in the motor, a low pass l-c filter can be inserted across the outputs of the cs3717a as shown in the following diagram. a b 2 a a a 2 a 2 in0 a full step motor drive 1m = 500ma half step motor drive 1m = 250ma stand by with holding torque 1m = 80ma in1 a direction a direction b in0 b in1 b 500 ma i ma 500 ma i mb - 500 ma - 500 ma 12345678 in out input and output sequences for half step and full step operation l ? l m 1 10 c ? 4 10 10 l c outa cs3717a outb l motor winding (l m , r m ) cs3717a application information: continued
6 test circuit 1 ? motor supply +36v v cc logic supply +5v v ref reference voltage +5v 1k ? r c r sense v rs v c c c 820 pf 56k ? r t c t 820 pf gnd sense comp in gnd pulse direction in0 in1 v dd a outa outb logic control inputs cs3717a motor winding l l ? 10mh r ? 13 ? v dd b waveforms with ma regulating (phase = 0) 0v v motor t on t off t v cc v out b 0v v out a t v dd 0v v comp in t v cx 0v v sense t v cx t d v f v sat v sat rec v sat cond cs3717a
7 application circuit - two phase bipolar stepper motor driver 1 ? v s 1k ? r c c c 0.1 f cs-3717a c2 c1 100 f 820pf 1k ? r c 1 ? r sense c c 820pf c t 820pf c t 820pf comp in gnd in0 56k ? r t 56k ? r t cs3717a i ma i mb mba maa stepper motor v ss 0.1 f c3 from processor gnd sense out b outa v dd a v dd b v cc v ref in1 direction pulse v cc v ref sense gnd pulse direction in0 in1 v dd a outa outb v dd b gnd r sense cs3717a comp in the r ja of the cs3717a can be reduced by soldering the gnd pins to a suitable copper area of the printed circuit board or to an external heatsink. the diagram of fig. 2 shows the maximum dissipated power p tot and the r ja as a function of the side l ?of two equal square copper areas having a thickness of 35 (see fig. 1). in addition, it is possible to use an external heatsink (see fig. 3). during soldering the pins tempera- ture must not exceed 260? and the soldering time must not be longer than 12 seconds. the external heatsink or printed circuit copper area must be connected to electrical ground. mounting instructions figure 2 - max. power dissipation and junction to ambient thermal resistance vs. size ?? for 16 lead fused package. 1 2 3 4 p tot (w) 10 20 30 40 i(mm) 0 0 20 40 60 80 (?c/w) 0 ? p tot (t amb = 70?c) r ja r ja l l copper area 35 thickness p.c. board figure 1 - example of p.c. board copper area which is used as heatsink with 16 lead fused package. 170mm 38.0mm 11.9mm 0 -50 1 2 3 4 5 p tot (w) 0 50 100 t amb (c) free air heat - sink with r th = 25?c/w with infinite heat - sink figure 3 - external heatsink mounting example (r th = 30?/w) for 16 lead batwing package. figure 4 - maximum allowable power dissipation vs. ambient temperature for 16 lead batwing package. cs3717a
8 part number description CS3717AGNF16 16 lead pdip (internally fused leads) d lead count metric english max min max min 16l pdip 19.69 18.67 .775 .735 (internally fused leads) 16 lead pdip thermal data (internally fused leads) r jc typ 15 c/w r ja typ 50 c/w package specification package dimensions in mm (inches) package thermal data ordering information cs3717a ?semiconductor components industries, llc, 2000 on semiconductor and the on logo are trademarks of semiconductor components industries, llc (scillc). on semiconductor reserves the right to make changes without further notice to any products herein. for additional infor- mation and the latest available information, please contact your local on semiconductor representative. archive device not recommended for new design plastic dip (n); 300 mil wide 0.39 (.015) min. 2.54 (.100) bsc 1.77 (.070) 1.14 (.045) d some 8 and 16 lead packages may have 1/2 lead at the end of the package. all specs are the same. .203 (.008) .356 (.014) ref: jedec ms-001 3.68 (.145) 2.92 (.115) 8.26 (.325) 7.62 (.300) 7.11 (.280) 6.10 (.240) .356 (.014) .558 (.022)
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