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a s1 7 2 0 s o l en o i d / va l v e d r i v e r w i th cu r r e n t l i m i t at i o n www.austriamicrosystems.com/solenoidrelaydriver/a s1720 revision 1.04 1 12 d ata sh eet 1 general description the AS1720a is a low side current source providing an optimized dc operation for power saving and ultra low electro magnetic radiation. the AS1720b is a low side switch providing a pwm ou tput, which frequency is defined by an internal rc oscillator. the adjustable pwm allows a fine control of the power delivered to the load. the AS1720a and AS1720b can be set to provide a str ong initial closure current and is automatically switching to h old mode for power saving. the initial dc current, the hold curr ent and the duty cycle of the pwm can be adjusted by external resist ors. an internal thermal sensor prevents damage of the circuit due t o excessive heating up. both devices are optimized for driving electromecha nical devices such as valves, solenoids relays, actuators and pos itioners. 2 key features supply range: +5v to +50v internal vdda: 3.3v supply current: 1 ma internal osc frequency: 30khz fix delay: 136ms adjustable duty cycle: 20% C 90% (AS1720b only) adjustable energizing current: 10ma C 100ma adjustable hold current: 30% 70% of energizing cu rrent current limitation thermal shutdown: 150oc 8pin mlpd (2x2mm) package on request soic 8 package (reduced temperature rang e 40c to +85c) 3 applications the AS1720 is ideal for fluid and gas flow systems, industrial control, electrical heaters, motor speed control. table 1. standard products model operation mode AS1720a dc current source operation AS1720b pwm switching operation l energising current adjust thermal shutdown pwm & control free- wheeling diode vsupply: +5v to +50v ih enn ie adjustable duty cycle hold current adjust internal vdda typ. 3.3v current adjust ldo & ref generator r1 r2 v ref 100nf r pu on off AS1720 delay 30khz oscillator vdda 3 duty 2 vdda 1 vddhv 4 out 5 vss 7 6 8 figure 1. AS1720 - block diagram r ie r ih r l 10nf
www.austriamicrosystems.com/solenoidrelaydriver/a s1720 revision 1.04 2 12 AS1720 datasheet p i n a s s i g n m e n t s 4 pin assignments figure 2. pin out (top view) pin description table 2. pin descriptions pin name pin number description vddhv 1 positive supply voltage vdda 2 internal supply of 3.3v (typ.) duty 3 duty-cycle. by means of this pin the duty cycle can be adjuste d between 20% and 90% during hold phase. the duty cycle can be adjusted by a voltage source or an external resistor divider. setting thi s pin to v dda the 50% duty cycle is selected automatically. out 4 current source output vss 5 ground ie 6 energize current. this pin defines the current during energize phase by means of a resistor. ih 7 hold current. this pin defines the current during hold phase by means of a resistor. enn 8 enable not. this pin can be used to switch on/off the current source (e.g. via a p), when the AS1720 is always powered on. low during startup: when vddhv is applied, the dev ice starts with the energise phase, followed by the hold phase. when the device is constantly powered on, it can be controlled by this pin. high: the output current source is switched off. low: the device starts with the energise phase, fol lowed by the hold phase. 1 vddhv AS1720 2 vdda 3 duty 4 out 8 enn 7 ih 6 ie 5 vss
www.austriamicrosystems.com/solenoidrelaydriver/a s1720 revision 1.04 3 12 AS1720 datasheet a b s o l u t e m a x i m u m r a t i n g s 5 absolute maximum ratings stresses beyond those listed in table 3 may cause permanent damage to the device. these ar e stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in section 6 electrical characteristics on page 4 is not implied. exposure to absolute maximum rating conditions for extended per iods may affect device reliability. table 3. absolute maximum ratings parameter min max units notes electrical parameters vddhv, out 0.9 +55 v vdda, duty, enn, ie, ih 0.3 +5 v input current (latchup immunity) 100 100 ma norm: je dec 78 @85c electrostatic discharge electrostatic discharge hbm +/ 1.5 kv norm: mil 883 e method 3015 temperature ranges and storage conditions thermal resistance q ja +36 oc/w junction temperature t j +140 oc internally limited storage temperature range 55 +150 oc package body temperature +260 oc the reflow peak soldering temperature (body temperature) specified is in accordance with ipc/ jedec j-std-020 moisture/reflow sensitivity classification for non-hermetic solid state surface mount devices. the lead finish for pbfree leaded packages is matte tin (100% sn). humidity 5 85 % noncondensing moisture sensitive level 1 represents a max. floor li fe time of unlimited
www.austriamicrosystems.com/solenoidrelaydriver/a s1720 revision 1.04 4 12 AS1720 datasheet e l e c t r i c a l c h a r a c t e r i s t i c s 6 electrical characteristics v ddhv = 5v, v ss = 0v, typical values are at t amb = +25oc (unless otherwise specified). all limits a re guaranteed. the parameters with min and max values are guaranteed with production tests or sqc (statistical quality control) methods. table 4. electrical characteristics symbol parameter conditions min typ max units t amb operating ambient temperature 40 +85 c t j operating junction temperature 40 +125 c valid for AS1720a & AS1720b v ddhv supply voltage range 5 50 v v dda internal supply no load 3.1 3.3 3.5 v i dd supply current 1 2 ma i out_e output energizing current range 1 1. the parameters are tested with proprietary test m odes. defined by r ie (see figure 10 on page 7) 10 100 ma v ih digital input threshold @ pin enn 2 v dda v v il v ss 1.2 v hyst hysteresis @ pin enn 200 mv r pu pullup resistor @ pin enn 100 k w delay time see delay on page 6 136 ms t shdn thermal shutdown temperature 160 oc d t shdn thermal shutdown hysteresis 15 oc only valid for AS1720a v out saturation voltage, sink 1 i out = 100ma 0.6 1 v k transfer value r ie = 12k w , v ddhv = 5v to 50v, out = 1v to 40v (see page 7) 1080 1200 1320 a w i out_h output hold current range 1 defined by r ih (see figure 10 on page 7) 0.3 x i out_e 0.7 x i out_e ma only valid for AS1720b minimum duty cycle 15 20 25 % maximum duty cycle 83 90 95 % internal duty cycle 50 % v trig trigger level to select internal voltage divider @ pin duty v dda v f pwm pwm frequency 25.5 30 34.5 khz
www.austriamicrosystems.com/solenoidrelaydriver/a s1720 revision 1.04 5 12 AS1720 datasheet ty p i c a l o p e r a t i n g c h a r a c t e r i s t i c s 7 typical operating characteristics v supply = 5v, r ie = 30k w , r ih = 120k w , t amb = +25oc (unless otherwise specified); figure 3. duty cycle vs. v duty figure 4. pwm frequency vs. temperature 20 30 40 50 60 70 80 90 0.5 0.75 1 1.25 1.5 1.75 2 2.25 2.5 voltage @ pin duty (v) duty cycle (%) 25 26 27 28 29 30 31 32 33 34 35 -40 -20 0 20 40 60 80 100 120 temperature (c) pwm frequency (khz) figure 5. supply current vs. supply voltage figure 6. supply current vs. temperature 360 370 380 390 400 410 420 430 440 5 10 15 20 25 30 35 40 45 50 v ddhv (v) i dd (a) 300 350 400 450 500 550 -40 -20 0 20 40 60 80 100 120 temperature (c) i dd (a) figure 7. transfer function vs. supply voltage fig ure 8. transfer function vs. temperature 1050 1100 1150 1200 1250 1300 1350 1400 5 10 15 20 25 30 35 40 v ddhv (v) transfer value k 1050 1100 1150 1200 1250 1300 1350 1400 -40 -20 0 20 40 60 80 100 120 temperature (c) transfer value k
www.austriamicrosystems.com/solenoidrelaydriver/a s1720 revision 1.04 6 12 AS1720 datasheet d e t a i l e d d e s c r i p t i o n 8 detailed description delay the delay time is generated internally by a digital divider. ldo and reference generator this block provides the internal supply voltage of typ. 3.3v and all bias currents for the analog cell s. further the external resistor divider for setting the duty cycle will be supplied. thermal shutdown the temperature is constantly monitored. if the tem perature exceeds typ. 160oc the output is disabled. in order to exit the over temperature condition, the device has to cool down and the reas on of over temperature (e.g. short circuit) must be removed. after exiting the overtemperature condition the system restarts beginning with the en ergizing phase followed by the hold phase. dc operation (AS1720a only) after power up, the delay time (see delay) starts running. after expiration of the delay the hold phase starts automatically. during the hold ph ase the dc output current is reduced according to the r ih on pin ih. pwm operation (AS1720b only) after power up, the delay time (see delay) starts running. after expiration of the delay the hold phase starts automatically. the internal rc oscillator sets the pwm period. the duty cycle is e ither defined by the external resistor divider (vol tage) at pin duty or by the fixed internal divider. when using the external divider the duty c ycle can be adjusted between 20% and 90% (e.g. from a dac). alternatively the pin can be driven by a voltage source. for using the internal divider the pin duty has to be connected to v dda . the comparator recognizes this condition and switches to the internal divider, which causes a fixed 50% duty cycle. figure 9. simplified circuit of block pwm and cont rol (eq 1) dutycycle v duty ( ) 0 381 , v duty 0 014 , C = duty adjustable duty cycle fixed 50% duty cycle optional pwm & control duty 30khz oscillator vdda r1 r2 v ref r pu enn on off internal vdda typ. 3.3v delay vdda vdda
www.austriamicrosystems.com/solenoidrelaydriver/a s1720 revision 1.04 7 12 AS1720 datasheet d e t a i l e d d e s c r i p t i o n control by pin enn when vddhv is constantly switched on the AS1720 can be controlled by pin enn. the functionality is the same as for controlling the device via pin vddhv. this feature is useful when controlling by a microprocessor is desired. because of the internal pullup resistor to v dda a microprocessor with opendrain or with push/pull (max 3.3v) output can be used. current adjust (AS1720a) and current limitation (AS1720b) this block provides the current reference for the o utput current source. the current is generated by r egulating the internal bandgap voltage to the pins ie and ih. the external resistors r ie and r ih define the output current and can be expressed as: the temperature coefficient depends on the bandgap voltage (100ppm/k, box method) and external resisto r (in the range of several ppm/k). the saturation voltage of the output current source for a 100ma current is typical 600mv. figure 10. simplified circuit of blocks current ad just and current source (eq 2) r ie ih k i out ------------ = current mirror 1.2v reference ie r ie 1.2v out r ih ih pwm & control
www.austriamicrosystems.com/solenoidrelaydriver/a s1720 revision 1.04 8 12 AS1720 datasheet a p p l i c a t i o n i n f o r m a t i o n 9 application information in order to drive relays, which need more than 100m a current, an external circuitry (see figure 11) can be used. this application shows how to drive 5w @12v relays. this circuit is only applicable for AS1720a. for this example with r1 = 100 w and r s = 2.5 w the current is is calculated as follows: figure 11. AS1720a - typical application (eq 3) i s i 1 r 1 r s ------ 0 01 a , 100 2 5 , --------- 400 ma = = = bc161 100 w lm741 i s relay vddhv vsupply: +12v ih enn duty ie vss out vdda 100nf AS1720a i 1 1v r1 r s 10ma r ie 120k w + - free- wheeling diode r ih 240k w energising current adjust hold current adjust
www.austriamicrosystems.com/solenoidrelaydriver/a s1720 revision 1.04 9 12 AS1720 datasheet p a c k a g e d r a w i n g s a n d m a r k i n g s 10 package drawings and markings figure 12. 8-pin mlpd (2x2mm) marking
www.austriamicrosystems.com/solenoidrelaydriver/a s1720 revision 1.04 10 12 AS1720 datasheet p a c k a g e d r a w i n g s a n d m a r k i n g s figure 13. 8-pin mlpd (2x2mm) package
www.austriamicrosystems.com/solenoidrelaydriver/a s1720 revision 1.04 11 12 AS1720 datasheet o r d e r i n g i n f o r m a t i o n 11 ordering information the device is available as the standard products sh own in table 5 . note: all products are rohs compliant and austriamicrosys tems green. buy our products or get free samples online at icdi rect: http://www.austriamicrosystems.com/icdirect technical support is found at http://www.austriamicrosystems.com/technicalsuppor t for further information and requests, please contac t us mailto:sales@austriamicrosystems.com or find your local distributor at http://www.austriamicrosystems.com/distributor table 5. ordering information ordering code marking description delivery form package AS1720aatdt a0 solenoid / valve driver with current limitation and with dc current source operation tape and reel 8pin mlpd (2x2mm) AS1720batdt aw solenoid / valve driver with current limitation and with pwm switching operation tape and reel 8pin mlpd (2x2mm)
www.austriamicrosystems.com/solenoidrelaydriver/a s1720 revision 1.04 12 12 AS1720 datasheet copyrights copyright ? 19972011, austriamicrosystems ag, tobe lbaderstrasse 30, 8141 unterpremstaetten, austriae urope. trademarks registered ?. all rights reserved. the material herein may not be reproduced, adapted, merged, translated, stored, o r used without the prior written consent of the copyright owner. all products and companies mentioned are trademarks or registered trademarks of their respective compa nies. disclaimer devices sold by austriamicrosystems ag are covered by the warranty and patent indemnification provisio ns appearing in its term of sale. aus triamicrosystems ag makes no warranty, express, sta tutory, implied, or by description regarding the in formation set forth herein or regarding the freedom of the described devices from patent infrin gement. austriamicrosystems ag reserves the right t o change specifications and prices at any time and without notice. therefore, prior to de signing this product into a system, it is necessary to check with austriamicrosystems ag for current information. this product is intended for u se in normal commercial applications. applications requiring extended temperature range, unusual environmental requirements, or high reliabi lity applications, such as military, medical lifes upport or lifesustaining equipment are specif ically not recommended without additional processin g by austriamicrosystems ag for each application. f or shipments of less than 100 parts the manufacturing flow might show deviations from the s tandard production flow, such as test flow or test location. the information furnished here by austriamicrosyste ms ag is believed to be correct and accurate. howev er, austriamicrosystems ag shall not be liable to recipient or any third party for any d amages, including but not limited to personal injur y, property damage, loss of profits, loss of use, interruption of business or indirect, special, inci dental or consequential damages, of any kind, in co nnection with or arising out of the furnishing, performance or use of the technical data herein. no obligation or liability to recipient or any third party shall arise or flow out of austriamicrosystems ag rendering of technical or ot her services. contact information headquarters austriamicrosystems ag tobelbaderstrasse 30 a8141 unterpremstaetten, austria tel: +43 (0) 3136 500 0 fax: +43 (0) 3136 525 01 for sales offices, distributors and representatives , please visit: http://www.austriamicrosystems.com/contact

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