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AS8401 multipurpose control asic for omnifet data sheet austria mikro systeme international ag
multipurpose control asic for omninet ? data sheet AS8401 rev. a december 1999 page 2 of 11 austria mikro systeme international ag key features multipurpose control asic for omnifet (sgs thompson intelligent power fet family) contains one channel on-chip applicable in low or high side switch circuits supply voltage range 10v ? 60v up to +/- 3v potential difference between system?s digital ground and power ground poss i - ble. current controlled interface provides load circuit surveillance and fault back signal typical rise time shorter then 2.4us typical fall time shorter then 3.8us 8 pin soic package general description the asic?s purpose is to drive one omnifet n-channel power fet device. (omnifet is a trademark of sgs-thomson). the omnifet?s integrated protection circuits (current limit a - tion, over temperature protection , ...) are supplied via the omnifet?s gate input. thus in the omnifet?s on-state, a dc gate current of 0.5ma is required. in a failure case (e.g. excessive temperature) an internal resistor of about 100 w is connected between the omnifet?s gate and source. this state is used to detect errors by the controlling asic. the control asic?s standard application is in the use as a high side or low side switch (selec t - able) in a 24v-supply system, where the functionality is guaranteed up to a maximum driver voltage of 55v. in the load dump case (vtr = 60v, pulse duration about 5ms, 5 pulses) the asic remains functioning (function state a) with modified parameters (rise times and fall times). the asic contains one driver circuit (omnifet driver) and realises the following functions: current controlled on switch / off switch with defined rise, fall and delay times (programm a - ble externally at the control input), that is usable as a high side or low side switch. automatic mode change between low side and high side use. this allows processing both, relatively low driver voltages (up to 25v, low side switch) and high driver voltages (up to 60v, high side switch) by detecting the present driver voltage related to omnifet?s source potential. error detection for the omnifet and generation of an error status signal. gate to source voltage limitation for the omnifet to a maximum of 13v (omnifet pr o - tection). floating ground interface between the controlling processor (control and status signal) and the driven omnifet; provided by separation of digital and power ground. the omnifet?s source potential is the asic?s ground. power reduction in the off-state (supply current falling to less than 80a after switching the asic off). the driver can be used as low or high side switch. the control and the fault back signal are realised with current sources in order to guarantee the separation of digital ground (of the processor) and power ground (at the load circuit). this is a safety function for a broken asic ground line and it fulfils emc demands.
multipurpose control asic for omninet ? data sheet AS8401 rev. a december 1999 page 3 of 11 austria mikro systeme international ag in applications as a high side driver the omnifet?s source is connected to the asic ground, which switches together with the load circuit. changes in the asic?s ground potential of up to 58v, and rise and fall speeds of up to 58v/s are permitted. functional description block diagram figure 1: block diagram of the AS8401 description from the functional view the chip can be divided into the following units: a driving circuit, which implements a current-controlled switching of the omnifet with current pulses of approximately +30 ma, and makes the following further functions available: detection of the operating condition of the omnifet and generation of an error status signal (output of a current of approximately 0.5 ma in the event of an error) defined delay of the switching-on-impulse of approximately 2.0s and implementation of a delay of the switch-off-impulse of smaller than 0.5s defined (current-controlled) rise/fall times of approximately. 2.0s/1,0s disconnection of the switching-on-impulse after approximately 5,0s and connecting a cu r - rent source of approximately 3 ma whilst the omnifet is switched on for the supply of the omnifet?s protective circuits and error recognition current sinking at the omnifet drive pin of up to 30 ma during the off state ensures a safe off status.
multipurpose control asic for omninet ? data sheet AS8401 rev. a december 1999 page 4 of 11 austria mikro systeme international ag 1. automatic mode recognition / mode switching, which is controlled by detection of the driver voltage vtr related to the source potential: operating as a low side switch (mode1), the driver voltage is approximately 10v and the point of switching is approximately 25v. when the AS8401 operates as a high side switch, during the transition of the omnifet to conduction, provided that the asic?s supply voltage, vtr, remains constant, the asic?s output current should be maintained. 2. a bandgap stabilised 5v voltage regulator, which generates the supply voltage for the digital control section and all the voltage references 3. a floating ground interface to the controlling processor (pin in), comprised of a reference current supply and a general current supply, which implements the following functions: generation of a logic voltage signal from the ground-free input current at the pin in in on-state there are further derived currents for the production of the delay and rise/fall times of the driver from the input current at the pin in after the omnifet has been switched off and an additional time delay, the control asic enters power down mode. during power down the current consumption is 80a or less. the time delay is necessary to ensure fast comparator operation in order to complete the power down s e quence. 4. a time-delayed power down circuit for the control of the generation of supply current (see point 4) 5. voltage delimitation which limits the voltage between gate and source of the omnifet to 13v 1,0v (protection of the omnifet). the asic controls the omnifet between gate and source (in particular also when it is used in high-side-switch applications). the operating condition in which the source potential is more positive than the gate potential, not permitted for the omnifet, is avoided. the use of the source potential of the omnifet as asic ground for the ground free coupling between asic and the processor causes fast variable asic ground potential during the switching operation particularly when the AS8401 is used in high side switch applications. the size of the switching-on pulses and switching-off pulses and thus the rise and fall times with given gate-source capacities of the omnifet can be programmed by an external resi s - tance r in , which determines the input current at the pin in, within certain limits. the switching time varies approximately in inverse proportion to the current i in at the pin in. thereby it is possible to adapt the AS8401 to the particular requirements of the omnifet (taking into a c - count gate source capacitance and required delay/transition times) within certain limits (this adjustment range is not constituent of these device specification). this adaptability is limited by the possible range of the current at the input pin in.
multipurpose control asic for omninet ? data sheet AS8401 rev. a december 1999 page 5 of 11 austria mikro systeme international ag definition of the logic signals symbol logic meaning level meaning in control input for the driver, the input is current controlled, i.e.: a) according to to a current from 0,1ma to dgnd externally pr o - duced b) according to no current (< 5 ma) i in = -0,1 ma i in = 0 a) appropriate driver output goes high (according to v out = v tr ) b) appropriate driver output goes low (according to v out = v source ) stat accumulated error status signal for the controlled omnifet, the output is current controlled, i.e.: a) fault condition according to a current from 0,35 ma to 0.5 ma from the asic to dgnd b) normally operation according to no current i stat = -0,5ma i stat = 0 error at the omnifet during the on- status (signal is valid after termin a - tion of the switch-on procedure) a) an error of the omnifet during the on-status, b) normal operation or off-status of the omnifet electrical characteristics absolute maximum ratings (non operating) symbol parameter min max note vtr - vpgnd dc supply voltage -0.5 v 55 v vdl load dump voltage 60v din 40839 vol. 2: 5 pulse, 500ms with ri = 2 ohm i inmax maximum input cu r - rent -30 ma 30 ma v in < v inmin respectively v in > vtr v ina digital input level vpgnd - 0.3v 55v t strg storage temperature -55 o c 150 o c t sold soldering temperature 260 o c 1) t sold soldering time 10 sec reflow and wave h humidity 5 % 85 % esd electrostatic discharge 1000 v hbm: r = 1.5 k w , c = 100 pf note: 1) 360 o c and 3s for manual soldering
multipurpose control asic for omninet ? data sheet AS8401 rev. a december 1999 page 6 of 11 austria mikro systeme international ag recommended operating conditions the following values are valid for a temperature range from ?40 to 105c and a supply voltage range vtr from 10v to 42v. if the supply voltage vtr rises above 42v and stays below 60v (load dump case) the circuit stay fully functional with different parameters. in every case it is guaranteed, that the switch-off-delay is 600ns shorter than the switch-on-delay. symbol parameter min typ max note static parameters driver circuit vtr driver voltage 10v 42v 1) vcc chip internal 5v power su p - ply 4.7v 5.0v 5.7v external using not allowed i vtroff leakage current to power ground (pgnd) in the off state 80a vtr = 10v, low side switch application, off state, i in = 0a, t = 27 o c 80a 100a vtr = 34v, high side switch application, off state, i in = 0a, t = 27 o c 150a vtr = 42v, high side switch application, off state, i in = 0a, t = 105 o c i vtron current consumption in on state 3ma vtr = 10v, on state, i in = 100a i outoff peak switch current of the driver in the switch-off phase 20ma 50ma 2) i outon peak switch current of the driver in the switch on- phase -60ma -30ma 3) i outn output current of the ?no r - mal-condition? in the on- state 0.3ma -30ma 4) i outf output current of the ?fault condition? in the on-state 2ma 4ma v sat normal saturation voltage of the ?normal-condition? in the on- state 0.5v v sat fault saturation voltage of the ?fault-condition? in the on- state 2v v out/source output voltage limitation between out and source 12v 14v 5) control input in i inon input current of the control signal for the on-state -100a 6) i inoff input current of the control signal for the off-state -5a 0 status output stat i statonf output current of status pin of the error case (fault co n - dition) for the on-state -1.2ma -0.5ma i statonn output current of status pin of the normal condition for the on-state -50a 5a
multipurpose control asic for omninet ? data sheet AS8401 rev. a december 1999 page 7 of 11 austria mikro systeme international ag recommended operating conditions (continued) symbol parameter min typ max note dynamic parameters t rise rise time 2.4s t fall fall time 3.8s t pdon switch on delay 0.75s 3.9s t pdoff switch off delay 4.0s t sp duration of the switch-on current pulse 4.0s 5.0s 7.0s note: 1) the maximum driver voltage vtr at full function it is vtr = 42v. at vtr = 60v in the load dump case all defined functions are staying valid (function state a). in this state it is possible that some times some param e - ters are different from the specified value, but in every time the switch off delay is shorter then the switch on delay. 2) valid for an input current i in = 0a. this possibility of the output out is valid the off state. 3) valid for an input current i in = 100a. this possibility of the output out is valid the on state. 4) this is the input current of the omnifet in the on-state 5) this is a chip internal dynamical limitation of the output voltage. 6) correspondent with the output current of the control circuit. the capacity on the pin in has to be low (c pin extern < 1 pf). the tolerance of this current controls the switch timing.
multipurpose control asic for omninet ? data sheet AS8401 rev. a december 1999 page 8 of 11 austria mikro systeme international ag soic-8 1 2 3 4 n.c . in n.c . stat source vcc out vtr as 8401 8 7 6 5 (top view) pin-out information pin description figure 2: pin-out AS8401 pin list pin no. pin name type description 1 n.c . not connected 2 in input control input of the driver 3 n.c . not connected 4 stat output output for state signal ( error state) 5 vcc output internal supply for logic (5v) 6 source ground source of the omnifet and ground of the asic 7 out output driver output (gate of the omnifet) 8 vtr supply supply of the driver
multipurpose control asic for omninet ? data sheet AS8401 rev. a december 1999 page 9 of 11 austria mikro systeme international ag application schematic high side switch figure 3: AS8401/omnifet as high-side switch low side switch figure 4: AS8401/omnifet as low-side switch
multipurpose control asic for omninet ? data sheet AS8401 rev. a december 1999 page 10 of 11 austria mikro systeme international ag grounding concept in figure 3 and 4 two possible application circuits for the AS8401/omnifet were shown. for a better understanding of this two application circuits in figure 5 a grounding/supply-concept for this two circuits is shown. figure 5: AS8401/omnifet application circuits grounding/supply-concept
multipurpose control asic for omninet ? data sheet AS8401 rev. a december 1999 page 11 of 11 austria mikro systeme international ag package information package : soic 8 small outline soic 8 soic 8 small outline marking (dimensions in mm) AS8401 chip number min. nom. max. yy year of production a 1,6 1,6 1,7 ww week of production a1 0,1 0,15 0,3 xxx assembly-id a2 1,40 1,5 1,6 b 0,4 0,4 0,5 c 0,19 0,2 0,3 d 4,8 4,9 5 e 3,8 3,9 3,99 e 1,27 bsc h 5,8 5,99 6,2 h 0,25 0,33 0,41 l 0,41 0,64 0,9 a 0 5 8 figure 6: physical package dimensions copyright ? 1999, austria mikro systeme international ag, schlo? premst?tten, 8141 unterpremst?tten, austria. telefon +43-(0)3136-500-0, telefax +43-(0)3136-52501, e-mail info@amsint.com all rights reserved. no part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, without the prior permission in writing by the copyright holder. to the best of its knowledge, austria mikro systeme international asserts that the information contained in this publication is accurate and correct. a1 a h x 45 a l e b d e h seating plane r 2 3 4 5 6 7 a2 c yywwxxx 1 8 AS8401

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