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| issue 1 - january 2008 1 www.zetex.com ? zetex semiconductors plc 2008 ZXLD1321 boost mode dc-dc converter for led driving with 1a output and current control description note # : using standard external components as specified under electrical characteristics. efficiency is dependent upon external component types and values. higher efficiency is possible with alternative coils. the ZXLD1321 is an inductive dc-dc converter, with an internal switch, designed for driving single or multiple leds in series up to a total of 1a output current. applications cover commercial environments with input voltages ranging from 1.2v to 12v. the device employs a variable 'on' and 'off' time control scheme wi th adjustable peak switch current limiting and supports step-up (boost) mode and self-powering bootstrap operating modes, offering higher power efficiency and lowe r system cost than conventional pfm circuitry. the device includes the dc-dc converter, a high-side current monitor and an npn switching transistor to provide an integrated solution offering small pcb size, competitive cost/performance, high power efficiency of dc-dc conversion and maximum led brightness/reliability. more importantly, it retains design flexibility to add customer specific features. the feedback control circuitry inside the ZXLD1321 provides excellent load and current regulation, resulting in very stable led current over the useful life of the battery and over the full operating temperature range. the led current can be adjusted from 100% down to 10% of the set value by applying a dc voltage to the adj pin and down to 1% by applying a pwm signal to the adj pin. an on- chip led protection circuit also allows output current to be reduced linearly above a predetermined threshold temperature using an external thermistor at the tadj pin. external resistors set nominal average led current and coil peak current independently. the device can be shut down by applying a continuous low level dc voltage to the adj pin. features ? 1.2v to 12v input voltage range ? up to 1a output current ? typical efficiency # >85% ? bootstrap operation enables input voltage down to 1v ? user-defined thermal control of led output current using external thermistor ? high output current stability over input voltage and temperature ? 12a typical standby current ? led current adjustable from 100% down to 2% ? adjustable soft-start ? drives up to 5 white leds in series applications ? high power led flashlights ? led back-up lighting ? general led lighting ? emergency lighting www.datasheet.co.kr datasheet pdf - http://www..net/
ZXLD1321 issue 1 - january 2008 2 www.zetex.com ? zetex semiconductors plc 2008 pin connections (t op-view) package view block diagram package 14-pin dfn with exposed pad 4mm x 3mm 0.50mm pitch 1.5w @t a =70c dfn14 package (bottom view). 45 chamfer denotes pin 1 www.datasheet.co.kr datasheet pdf - http://www..net/ ZXLD1321 issue 1 - january 2008 3 www.zetex.com ? zetex semiconductors plc 2008 absolute maximum ratings (voltages relative to gnd unless otherwise stated) dc-dc converter high-side current monitor switching npn transistor these are stress ratings only. operation outside the absolute maximum ratings may cause device failure. operation at the absolute maximum ratings for extended periods may reduce device reliability. thermal resistance operating temperature (top) -40 to 125 c storage temperature (tst) -55 to 150 c junction temperature (tj) -40 to 150 c package power dissipation (ptot) dfn-14 with exposed pad: 4mmx3mm, 0.5mm pitch 1.5w at tamb = 70 c supply voltage (vin) -0.3v to +12v adj -0.3v to the lower of (+5.0v) or (vin + 0.3v) cfb -0.3v to the lower of (+5.0v) or (vin + 0.3v) isense -0.3v to the lower of (+5.0v) or (vin + 0.3v) tadj -0.3v to the lower of (+5.0v) or (vin + 0.3v) bias -0.3v to the lower of (+5.0v) or (vin + 0.3v) monitor supply voltage (m_vin) -0.3v to +18v continuous sense voltage (m_vin ? m_load) -0.3v to +5v collector-base voltage (v cbo )18v collector-emitter voltage (v ceo )18v peak pulse current (i cm ) 3a (pulse width = 300s. duty cycle<=2%) continuous collector current (i c )2a junction to case (r jc ) nominal value dfn-14 26.3c/w www.datasheet.co.kr datasheet pdf - http://www..net/ ZXLD1321 issue 1 - january 2008 4 www.zetex.com ? zetex semiconductors plc 2008 pin description name pin # description adj 1 adjust input ? leave floating, or connect to vref to set 100% output current. ? drive with dc voltage. (50mv ZXLD1321 issue 1 - january 2008 8 www.zetex.com ? zetex semiconductors plc 2008 output current regulation parameters notes: (f) system parameter only. this value is dependent upon external components and circuit configuration. (g) this refers to the accuracy of output current regulation under normal operation when the feedback loop incorporating the current monitor is active. the tolerances of ext ernal components are not included in this figure. ordering information symbol parameter conditions min typ max units i out minimum output/ led current (f) vin>3v 2 a i out output current accuracy (g) 3.0v ZXLD1321 issue 1 - january 2008 9 www.zetex.com ? zetex semiconductors plc 2008 device description the ZXLD1321 is a inductive boost dc-dc converter, with an internal switch, designed for driving single or multiple leds in series up to a total of 1a output current. depending upon supply voltage (v in ), led forward voltage drop (v led ) and circuit configuration, this can provide up to 8w of output power. applications cover v in ranging from 1.2v to 12v. the device employs a modified pulse frequency modulation (pfm) control scheme, with variable "on" and "off" time control and adjustable peak switch current limiting. general device operation (refer to block diagram) normal operation control is achieved by sensing the le d current in a series resistor (r m ), connected between the two inputs of the led current monitor. this genera tes a proportional current (imon) that charges the external integrator capacitor c fb . i mon is balanced against a reference discharge current (i adj ) generated at the output of a second voltage to current converter driven from the demand voltage (v adj) on the adj pin. the difference between i mon and i adj is integrated by c fb to produce an error voltage. a comparator takes a summed version of the voltage at the isense pin and a fraction of this cfb voltage and resets the latch driving the switch when the sum is greater than 50mv. the switch transistor is turned on by the output of the sr latch, which remains set until the emitter current in the switch transistor produces a voltage drop vsense (=50mv nominal) in external resistor rsense, defining a preset maximum switch current of 50mv/rsense. operation is such that a rising error voltage on cfb will effectively lower the voltage required on the isense pin and therefore reset the latch earlier in the sw itching cycle. this will reduce the 'on' time of the switch and reduce the peak current in the switch from its preset maximum value. similarly, a falling error voltage will reset the latch later and the peak switch current will be increased. the control loop therefore reduces or increases the energy stored in the coil during each switching cycle, as necessary, to force the led current to the set value. thi s results in high accuracy, as no error is needed in the led current to drive the servo to the required region. the time taken for the coil current to reach the peak value depends on several factors: the supply voltage, the peak coil current required at that particular led power and whether the system operates in "continuous" or "discontinuous" m ode. the time allowed for the coil current to discharge into the led is fixed by the 'variabl e off delay' monostable, whose period is modified by the power demand signal on the adj pin. th is monostable determines the time for which the latch remains reset (switch off) and provides a longer "off" period at lower power settings, helping to keep the parameters within an acceptable range. note that the "on" period and the "off" period are set by the supply voltage, led power and external components chosen. the frequency is therefore determined by these parameters and is not fixed. in this mo dified pfm scheme, the external components can be chosen to keep the frequency well above the audio range for all extremes of parameters, so no audible whistling should ever occur. the 500mv reference voltage defines the nominal vadj voltage and this defines the 100% output current. for lower led currents, the adj pin can be-driven from an external dc voltage (50mv ZXLD1321 issue 1 - january 2008 11 www.zetex.com ? zetex semiconductors plc 2008 application notes setting peak coil current the peak current in the coil is set by the resistor (r sense ) between the switch emitter and ground according to the minimum peak current will depend on opera ting mode, coil inductance and supply voltage range. the maximum peak current must not exceed the specified value for the switch. (see application circuits for details). setting led current the nominal average led current is given by where r m is the external resistor connected between pins m_vin and m_load. this current can be adjusted to a lower value by applying a dc control voltage or pwm control signal to the adj pin. dc control the led current can be adjusted over a 10% to 100% range by connecting a variable resistor r adj from the adj pin to ground to vary the dc voltage at the adj pin. r adj forms the lower part of a resistive divider and the internal 100k resistor between the adj and vref pins forms the upper part. a value of 1m for radj will therefore give a maximum current of 91% of i led (nom) and the device will be turned off when the voltag e on the adj pin falls below 28mv, corresponding to an r adj value of approximately 5k . if required, an end-stop resistor in series with r adj can be used to maintain the voltage on the adj pin above the turn-on threshold. using a logarithmic potentiometer for r adj will give an approximately linear variation of output current with shaft rotation. (fig 1) if required, the maximum output current can be re stored to 100% by adjusting the value of the led current monitor resistor (r m ). the tolerance of the internal 100k resistor and r adj should be taken into account when calculating output current. the adj pin is clamped internally to a voltage of 575mv (nom), to limit maximum average output current to approximately 115% of i led (nom). rsense mv i swpeak 50 = m led r mv nom i 100 ) ( = www.datasheet.co.kr datasheet pdf - http://www..net/ ZXLD1321 issue 1 - january 2008 12 www.zetex.com ? zetex semiconductors plc 2008 fig 1 pwm control a wider dimming range can be achieved by applyi ng a pwm control signal to the adj pin to turn the device on and off, giving an average output current proportional to the duty cycle of the control signal. the adj pin can be driven directly from the open drain nmos output of a microcontroller, or indirectly with a low satu ration voltage npn transistor such as the zetex zxtn25015dfh. (fig 2). fig 2 in the circuit of fig 4, the average led output current will be where duty cycle a pwm frequency of 200hz, or lower is recommended, to minimize errors due to the rise and fall times of the converter output. ZXLD1321 adj zxtn25015dfh d nom i avg i led led * ) ( ) ( = ) 2 1 ( 2 t t t d + = www.datasheet.co.kr datasheet pdf - http://www..net/ ZXLD1321 issue 1 - january 2008 13 www.zetex.com ? zetex semiconductors plc 2008 thermal compensation of led current high-luminance leds often need to be supplied with a temperature compensated current in order to maintain stable and reliable operation at high temperatures. this is usually achieved by reducing the led current proportionally from its nominal set value when the led temperature rises above a predefined threshold. (fig.3) fig 3 the 'thermal compensation current' generator inside the ZXLD1321 provides the necessary thermal compensation current to meet this requirement, using an ntc thermistor and resistor. (fig 4) fig 4 the tadj pin of the device has a voltage thresh old of 75mv nominal, which is derived from the reference voltage vref. if the voltage (v tadj ) on the tadj pin is held above the threshold, the thermal compensation current will be zero and no thermal compensation is applied. however, if v tadj falls below the threshold, a thermal compensation current (i tc ) is produced that is proportional to v tadj . i tc is injected into the control loop in such a way as to reduce the demand current i adj , causing the control loop to decrease the led current. the led current will be reduced to less than 10% of the set value when v tadj falls below 50mv. the threshold voltage has been chosen to set a nominal threshold of 105 c and the device has been optimized to operate with a standard 103kt1608 thermistor and 5k resistor in the potential divider. circuit details are given in the applicat ion notes. alternative thermistor/resistor networks can be used providing the input resistance presented to the device at the tadj pin is similar at the threshold temperature. if no led thermal co mpensation is required, the tadj pin should be connected to vref to disable this function. i led led temperature www.datasheet.co.kr datasheet pdf - http://www..net/ ZXLD1321 issue 1 - january 2008 14 www.zetex.com ? zetex semiconductors plc 2008 typical operating conditions inductive converters can operate in either c ontinuous mode, where current always flows in the inductor, but rises during th e on period and falls during th e off period, or discontinuous mode, where the current falls to zero during the off period. the mode depends on several factors, including supply voltage, output (led) voltage and the choice of peak current and inductor value. calculati ons need to be done to determine which mode the converter will be in. the circuit should be designed to give slightly more led current than required under the lowest supply voltage, so the control loop can regulate the current accurately. if the theoretical led current is less than that required, the control loop will not be able to reach the required value. the calculations will give an idea of the on and off times and hence the operating frequency, but bear in mind that the control loop will reduce the peak current to achieve the exact programmed led current and this will raise the operating fre quency. in general, values in the discontinuous mode are simpler to calculate because the current can go from zero to the theoretical maximum during the on period and fall to zero during the off period. in continuous mode the current will start from some value, so the on time will be lower to reach the theoretical maximum and lower still when the control loop reduces the peak current below the maximum. circuit operation operation of boost led driver the input voltage must always be lower than the led voltage. this circuit has an on phase, where the coil is connected from the supply to ground and an off phase, where the coil current flows through the led via a schottky diode. the current therefore only flows into the led circuit during the off phase, although the reservoir ca pacitor c3 should keep current flowing in the led(s) continuously. adj is set between 50mv and 500mv to give between 10% and 100% power respectively. making r2 = zero gives a base current to the output transistor of 50ma nominal and making r2 = 1.68k gives 10ma nominal. the reduced base current will lower supply current and hence improve efficiency in lower power applications. making r1 = 25m gives a peak coil current of 2 amps. the internal power transistor turns on until the coil current builds up to the peak value. at this point the transistor swit ches off and the coil current continues to flow in the led(s) via schottky diode d1. www.datasheet.co.kr datasheet pdf - http://www..net/ ZXLD1321 issue 1 - january 2008 15 www.zetex.com ? zetex semiconductors plc 2008 the led current is sensed by r3 and the controller varies this until the drop in r3 equals 20% of v adj . hence making r3 = 100m and v adj = 500mv gives a led current of 1 amp because the 500mv v adj results in 100mv across r3 wh ich equals 1 amp. making v adj = 10mv gives a led current of 100ma because the 50mv v adj results in 10mv drop across r3 which equals 100ma. the power is controlled by the chip backing off the pe ak coil current, so it is necessary to calculate the coil inductance and current to guarantee slightly more than 100% led power, so the circuit can control it effectively. the internal control loop is compensated by c1, which is normally 10nf. if the thermistor (r5) is used, the power will be backed off progressively as the tadj pin goes low. with the tadj pin above 75mv, power is 100% and this is reduced to zero when the tadj pin reaches 50mv. making r4 = 5k and using a 103kt1608 thermistor, the thermistor will reach 869 at 105c giving v tadj = 74mv which will start to reduce the led power above 105c. by 125c the thermistor will reach 547 giving v tadj = 50mv which gives zero power. this will protect the led from damage. these temperature values can be set by the customer by using a different thermistor or a different value of r4. if protection is not required, leaving the tadj pin open circuit will make it float to a high voltage and always give 100% power. reference part no value manufacturer contact details u1 ZXLD1321 led driver zetex www.zetex.com d1 zxcs2000 schottky diode zetex l1 mss7341-103ml 10h 2a coilcraft www.coilcraft.co m l1 npis64d100mtrf 10h 2a nic www.niccomp l1 744 77810 10h 2a wurth www.wurth.co.uk c1 generic 10nf 10v generic c2 grm31cr71h475k 4.7f 50v murata 1206 www.murata.com c3 grm31mr71e225k 2.2f 25v murata 1206 www.murata.com r1 generic 25m generic 0805 r2 generic generic 0603 r3 generic 100m generic 0805 r4 generic 5.1k generic 0603 r5 thermistor ntc 10k 103kt1608 www.datasheet.co.kr datasheet pdf - http://www..net/ ZXLD1321 issue 1 - january 2008 16 www.zetex.com ? zetex semiconductors plc 2008 operation in bootstrap mode diagram b : bootstrap mode operation of bootstrap led driver this is used when the input voltage is less than 2 volts. note that the chip vin now goes to the cathode of the schottky diode d1. the control loop can not operate at this low voltage, so the chip goes into a start-up mode, where the output transistor is switched on and off at nominally 50khz with a 50:50 duty cycle with about 10ma of base current into the power transistor (20% of nominal). the emitter current is still sensed by r1 and the "on" part of the duty cycle will be terminated either when the emitter sense voltage reaches 10mv (corresponding to 20% of the set peak current) or the on part of the duty cycle fini shes after 10s. there is no control of the led current yet, the circuit just opera tes in boost mode. eventually, the reservoir capacitor c3 charges up to 2v and the chip goes into "normal" mode, where it delivers 50ma to the base of the power transistor and the control loop works normally. it will continue to charge c3 until the led current is correctly established, with the chip now running from a voltage equal to the led forward drop (around 3.6v for one led) even though the supply is still below 2 volts. once the circuit has reached this condition, the rest of the descripti on of the operation is the same as for the boost operation. like the boost circuit, this ci rcuit has an on phase, where the coil is connected from the supply to ground and an off phase, where the coil current flows through the led via the schottky diode d1. the current therefore only flows into the le d circuit during the off phase, although the reservoir capacitor c2 should keep current flowing in the led(s) continuously. adj is set between 50mv and 500mv to give between 10% and 100% power respectively. making r2 = zero gives a base current to the output transistor of 50ma nominal and making r2 = 1.68k gives 10ma nominal. the reduced base current will lower supply current and hence improve efficiency in lower power applications. making r1 = 50m gives a peak coil current of 1 amps. the internal power transistor turns on until the co il current builds up to the peak. at this point the transistor switches off and th e coil current continues to flow in the led(s) via schottky diode d1. www.datasheet.co.kr datasheet pdf - http://www..net/ ZXLD1321 issue 1 - january 2008 17 www.zetex.com ? zetex semiconductors plc 2008 the led current is sensed by r3 and the controller varies this until the drop in r3 equals 20% of vadj. hence making r3 = 100m and vadj = 500mv gives a led current of 1 amp because the 500mv vadj results in 100mv across r3 which equals 1 amp. making vadj = 10mv gives a led current of 100ma because the 50mv vadj results in 10mv drop across r3 which equals 100ma. the power is controlled by the chip backing off the pe ak coil current, so it is necessary to calculate the coil inductance and current to guarantee slightly more than 100% led power, so the circuit can control it effectively. the internal control loop is compensated by c1, which is normally 10nf. note that in bootstrap mode, the input current will be 2 or 3 times larger than the led current and the duty cycle will be such that ton is larger than toff, due to the fact that the supply voltage charging the coil is low. because of this, larg e led currents can not be programmed at very low supply voltages, as the transistor current would need to exceed 2 amps. if the thermistor (r5) is used, the power will be backed off progressively as the tadj pin goes low. with the tadj pin above 75mv, power is 100% and this is reduced to zero when the tadj pin reaches 50mv. making r4 = 5k and using a 103kt1608 thermistor, the thermistor will reach 869 at 105c giving tadj = 74mv which will start to reduce the led power above 105c. by 125c the thermistor will reach 547 giving tadj = 50mv which gives zero power. this will protect the led from damage. these temperature values can be set by the customer by using a different thermistor or a different value of r4. if protection is not required, leaving the tadj pin open circuit will make it float to a high voltage and always give 100% power. reference part no value manufacturer contact details u1 ZXLD1321 led driver zetex www.zetex.com d1 zxcs2000 schottky diode zetex l1 mss7341-103ml 10h 2a coilcraft www.coilcraft.co m l1 npis64d100mtrf 10h 2a nic www.niccomp l1 744 777910 10h 2a wurth www.wurth.co.uk c1 generic 10nf 10v generic c2 grm31cr71h475k 4.7f 50v murata 1206 www.murata.com c3 grm31mr71e225k 2.2f 25v murata 1206 www.murata.com r1 generic 25m generic 0805 r2 generic generic 0603 r3 generic 100m generic 0805 r4 generic 5.1k generic 0603 r5 thermistor ntc 10k 103kt1608 www.datasheet.co.kr datasheet pdf - http://www..net/ ZXLD1321 issue 1 - january 2008 18 www.zetex.com ? zetex semiconductors plc 2008 additional notes which apply to all operational modes note with all these circuits that the on time is set by the time it takes the coil to reach the peak current. this peak value is reduced by the control loop to give the desired led power, so the on time can vary over a wide range. the minimum coil current can be zero (discontinuous operation) or finite (continuous operation) depending on the supply voltage, led current and the led voltage. the off time is set by an internal timer and is nominally 1.2s at 100% led power (v adj = 500mv), increasing to about 8s at 10% led power (v adj = 50mv). the longer off time and variable peak current enables the circuit to di m the led whilst maintaining continuous switching, rather than "skipping" or stalling and continuou s running is better for reducing elec trical noise and also for eliminating audibl e noise from the coil core. layout considerations as with all switching dc to dc converters, the currents can be large. using small inductors with a reasonably high supply voltage wi ll cause currents to change quickly. high di/dt can cause inductively-coupled spikes into adjacent tracks. at the transition from of the on phase to the off phase and back, where the power transistor switches, the voltage at the collector rises and falls quickly. high dv/dt can cause capacitively coupled spikes into adjacent tracks, especially if they have a high impedance. for this reason, all tracks on the pcb should be thick, to minimise drops, and short to keep all the components coupled tightly together. a double-sided board should be used with a gr ound plane to screen the tracks and provide a good ground return for the various functions and the rear exposed pad on the package should have an appropriately-sized land with good ground connecti ons, both to reduce electrical noise due to ground drops and to improve thermal conductivity. the input decoupling capacitor c1 should be ver y close to the chip pins and the led sense resistor r3 should have kelvin tracks to m_vin and m_load to achieve led current measurement accuracy, as the pcb tracks will have comparable resistance to the 100m resistor, so taking sense tracks to the current monitor which are not connected close to the ends of r3 will cause a measurement error. the peak current sense resistor r1 should have short tracks to the ground at the bottom end and kelvin tracks to isense at the top end. this resistor might need to be only 25m and pcb track resistance becomes comparable if the tracks are not very short. isense is a high impedance input, so a thin track from this pin directly to the top of r sense resistor r1 will still give an accurate measurement. the adj pin should have short tracks, as this is a fairly low-level signal controlling the power of the system. as it needs to be less than 28mv for shutdown, a close ground connection is needed for the pull-down device, as any ground drops could raise the potential. in particular, if a bipolar transistor is used as a pull-down device, this will have an appreciable v sat , which could perhaps be half the shutdown potential. the bottom of the thermistor must be coupled very closely to ground, as the tadj pin varies the led current from 100% to 0% for a voltage change of only 25mv, so any noise on the bottom of the thermistor will seriously affect the ac curacy of the thermal protection circuit. www.datasheet.co.kr datasheet pdf - http://www..net/ ZXLD1321 issue 1 - january 2008 19 www.zetex.com ? zetex semiconductors plc 2008 package outline - tdfn1443 note: controlling dimensions are in millimeters. ap proximate dimensions are provided in inches dim inches millimeters dim inches millimeters min max min max min max min max a 0.0276 0.0315 0.70 0.80 d2 0.1240 0.1279 3.15 3.25 a1 0.00 0.002 0.00 0.05 e 0.0197 bsc 0.50 bsc a3 0.008 ref. 0.203 ref. e 0.1161 0.1201 2.95 3.05 b 0.0079 0.0118 0.20 0.30 e2 0.0650 0.0689 1.65 1.75 d 0.1555 0.1594 3.95 4.05 l 0.0138 0.0177 0.35 0.45 e d a a1 a3 d2 b l e2 60.3938 pin 1 dot by marking chamfer 0.300 x 45 pin #1 identification www.datasheet.co.kr datasheet pdf - http://www..net/ ZXLD1321 issue 1 - january 2008 20 www.zetex.com ? zetex semiconductors plc 2008 zetex sales offices europe zetex gmbh kustermann-park balanstra?e 59 d-81541 mnchen germany telefon: (49) 89 45 49 49 0 fax: (49) 89 45 49 49 49 europe.sales@zetex.com americas zetex inc 700 veterans memorial highway hauppauge, ny 11788 usa telephone: (1) 631 360 2222 fax: (1) 631 360 8222 usa.sales@zetex.com asia pacific zetex (asia ltd) 3701-04 metroplaza tower 1 hing fong road, kwai fong hong kong telephone: (852) 26100 611 fax: (852) 24250 494 asia.sales@zetex.com corporate headquarters zetex semiconductors plc zetex technology park, chadderton oldham, ol9 9ll united kingdom telephone: (44) 161 622 4444 fax: (44) 161 622 4446 hq@zetex.com ? 2008 published by zetex semiconductors plc definitions product change zetex semiconductors reserves the right to alter, without notice, specifications, design, price or conditions of supply of any product or service. customers are solely responsible for obtaining th e latest relevant information before placing orders. applications disclaimer the circuits in this design/application note are offered as desi gn ideas. it is the responsibility of the user to ensure that t he circuit is fit for the user?s application and meets with the user?s requirements. no representation or warranty is given and no liability whatsoev er is assumed by zetex with respect to the accuracy or use of such in formation, or infringement of patents or other intellectual prop erty rights arising from such use or otherwise. zetex does not assume any le gal responsibility or will not be held legally liable (whether in contract, tort (including negligence), breach of statutory duty, restricti on or otherwise) for any damages, loss of profit, business, con tract, opportunity or consequential loss in the use of th ese circuit applications, under any circumstances. life support zetex products are specifically not authorized for use as critic al components in life support devices or systems without the ex press written approval of the chief executive officer of zetex semiconductors plc. as used herein: a. life support devices or systems are devices or systems which: 1. are intended to implant into the body or 2. support or sustain life and whose failure to perform when proper ly used in accordance with instructions for use provided in t he labelling can be reasonably expected to result in significant injury to the user. b. a critical component is any component in a life support devi ce or system whose failure to pe rform can be reasonably expected to cause the failure of the life support device or to affect its safety or effectiveness. reproduction the product specifications contained in this publication are issu ed to provide outline information only which (unless agreed by the company in writing) may not be used, applied or reproduced for any purpose or form part of any order or contract or be regarded as a representation relating to the pr oducts or services concerned. terms and conditions all products are sold subjects to zetex? terms and conditions of sale, and this disclaimer (save in the event of a conflict bet ween the two when the terms of the contract shall prevail) according to region, supplied at the time of order acknowledgement. for the latest information on technology, delivery terms and condi tions and prices, please contact your nearest zetex sales off ice. quality of product zetex is an iso 9001 and ts16949 certified semiconductor manufacturer. to ensure quality of service and products we strongly advise the purchase of parts dire ctly from zetex semiconductors or one of our regionally authorized distributors. for a complete listing of authorized distributors please visit: www.zetex.com/salesnetwork zetex semiconductors does not warrant or accept any liability whatsoever in respect of any parts purchased through unauthorized sales channels. esd (electrostatic discharge) semiconductor devices are susceptible to damage by esd. suitab le precautions should be taken when handling and transporting dev ices. the possible damage to devices depends on the circumstances of the handling and transporting, and the nature of the device. the extent of damage can vary from immediate functional or parametric malfunc tion to degradation of function or performance in use over ti me. devices suspected of being affected should be replaced. green compliance zetex semiconductors is committed to envir onmental excellence in all aspects of its operations which includes meeting or exce eding regulatory requirements with respect to the use of hazardous s ubstances. numerous successful programs have been implemented to reduce the use of hazardous substances and/or emissions. all zetex components are compliant with the ro hs directive, and through this it is supporting its customers in their compliance with weee and elv directives. product status key: ?preview? future device intended for production at some point. samples may be available ?active? product status recommended for new designs ?last time buy (ltb)? device will be discontinued and last time buy period and delivery is in effect ?not recommended for new designs? device is still in production to support existing designs and production ?obsolete? production ha s been discontinued datasheet status key: ?draft version? this term denotes a very early datasheet ver sion and contains highly provisional information, which may change in any manner without notice. ?provisional version? this term denotes a pre-release datasheet. it provides a clear indication of anticipated performance. however, changes to the test conditions and specif ications may occur, at any time and without notice. ?issue? this term denotes an issued datasheet cont aining finalized specifications. however, changes to specifications may occur, at any time and without notice. www.datasheet.co.kr datasheet pdf - http://www..net/ |
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