View MAX4990E_2489731.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

general description the MAX4990E high-voltage dc-ac converter is ideal for driving electroluminescent (el) lamps. the MAX4990E features a wide +2.4v to +5.5v input range that allows the device to accept a wide variety of voltage sources such as single-cell lithium-ion (li+) batteries and higher voltage battery chargers. the lamp outputs of the device generate up to 250v peak-to- peak output voltage for maximum lamp brightness. the MAX4990E utilizes an inductor-based boost con- verter to generate the high voltage necessary to drive an el lamp. the boost-converter switching frequency is set with the combination of an external capacitor con- nected from sw to gnd and an external resistor con- nected from slew to gnd. the MAX4990E uses a high-voltage full-bridge output stage to convert the high voltage generated by the boost converter to an ac waveform suitable for driving the el panel. the el output switching frequency is set with the combination of an external capacitor connect- ed from el to gnd and an external resistor connected from slew to gnd. the MAX4990E uses a proprietary acoustic noise- reduction circuit that controls the slew rate of the ac voltage, reducing audible noise from the el panel. the slew rate is set with an external resistor connected from slew to gnd. the MAX4990E features an el lamp dimming control (dim) that allows the user to set the el output voltage with a pwm signal, a dc analog voltage, or a resistor connected from the dim input to gnd. a capacitor placed in parallel to the resistor on dim allows the user to program a slow turn-on/-off time that generates a soft fade-on/fade-off effect of the el lamp. the MAX4990E enters a low-power shutdown mode (100na max) when the en and dim inputs are connect- ed to gnd. the MAX4990E also enters thermal shut- down if the die temperature rises above +158?. the MAX4990E is available in a space-saving, 14-pin, 3mm x 3mm tdfn package and is specified over the extended -40? to +85? operating temperature range. features ? esd-protected el lamp outputs 15kv human body model 4kv iec 61000-4-2 contact discharge 15kv iec 61000-4-2 air-gap discharge ? 250v p-p (max) output for highest brightness ? wide +2.4v to +5.5v input voltage range ? resistor-adjustable slew-rate control for audible noise reduction ? externally driven lamp and switching converter frequencies ? capacitor-adjustable lamp and switching converter frequencies ? low 100na shutdown current ? dim input for controlling output voltage through dc analog voltage, pwm, or resistor to gnd ? capacitor adjustable for slow turn-on/-off ? space-saving packages 14-pin, 3mm x 3mm tdfn applications MAX4990E high-voltage, 15kv esd-protected electroluminescent lamp driver ________________________________________________________________ maxim integrated products 1 19-0886; rev 0; 8/07 for pricing, delivery, and ordering information, please contact maxim direct at 1-888-629-4642, or visit maxim? website at www.maxim-ic.com. ordering information note: the device operates over the -40? to +85? operating temperature range. + denotes a lead-free package. ep = exposed paddle. part pin-package top mark pkg code ?5kv protection dim control slew-rate control MAX4990Etd+ 14 tdfn-ep (3mm x 3mm) adl t1433-2 yes yes yes keypad backlighting mp3 players lcd backlighting pdas/smartphones automotive instrument clusters MAX4990E tdfn-ep top view 245 13 11 10 n.c. n.c. cs en el sw 1 + 14 v a slew 3 12 v b dim 6 9 n.c. v dd 7 8 lx gnd *ep = exposed pad. connect ep to gnd or leave unconnected. *ep pin configuration typical application circuits appear at end of data sheet.
MAX4990E high-voltage, 15kv esd-protected electroluminescent lamp driver 2 _______________________________________________________________________________________ absolute maximum ratings electrical characteristics (v dd = +2.4v to +5.5v, c lamp = 10nf, c cs = 3.3nf, l x = 220? (i sat = 170ma, r s = 5.5 ), t a = t min to t max , unless otherwise noted. typical values are at v dd = +3.0v and t a = +25?.) (note 1) stresses beyond those listed under ?bsolute maximum ratings?may cause permanent damage to the device. these are stress rating s only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specificatio ns is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. (all voltages referenced to gnd.) v dd ...........................................................................-0.3v to +7v cs, lx...................................................................-0.3v to +160v v a , v b .........................................................-0.3v to (v cs + 0.3v) en, el, slew, dim, sw .............................-0.3v to (v dd + 0.3v) continuous power dissipation (t a = +70?) 14-pin tdfn (derate 24.4mw/? above +70?) ...... 1951mw j a .................................................................................41?/w operating temperature range ...........................-40? to +85? junction temperature ......................................................+150? storage temperature range .............................-65? to +150? lead temperature (soldering, 10s) .................................+300? parameter symbol conditions min typ max units power-supply voltage v dd 2.4 5.5 v power-supply current i dd r slew = 375k , slope = 30v/100?; f el = 200hz, v a - v b = 250v p-p 350 ? en = 0v, dim = 0v, t a = +25? 25 100 shutdown supply current i shdn en = 0v, dim = 0v, t a = -40? to +85? 300 na shutdown inductor supply current ilx shdn en = 0v, dim = 0v, lx = v dd , cs = v dd 1500 na undervoltage lockout v lo v dd rising 1.8 2.1 2.3 v uvlo hysteresis v hyst 125 mv el outputs (v a - v b ) v dd = +3v, dim = +0.5v 84 100 122 v dd = +3v, dim = +1v 170 200 230 peak-to-peak output voltage v a - v b v dd = +3v, dim = +1.3v 210 250 280 v pulldown switch on-resistance r onpd i sink = 1ma, v cs = +10v, v a , v b < +0.6v, v dd = +3v 50 165 500 pullup switch on-resistance r onpu v cs = +125v, i source = 1ma 700 1500 2200 i lkg_nmos v a = +125v, v b = +125v, shutdown mode, v cs = +125v -1 +1 switch off-leakage i lkg_pmos v a = 0v, v b = unconnected, shutdown mode, v cs = +125v -60 +60 ? v a , v b differential resistor v ab_res v a = +0.1v, v b = 0v, shutdown mode, cs = unconnected 27m el lamp switching frequency f el c el = 872pf, r slew = 375k 210 250 290 hz human body model ?5 iec 61000-4-2 contact discharge ? esd protection (v a , v b only) iec 61000-4-2 air-gap discharge ?5 kv
MAX4990E high-voltage, 15kv esd-protected electroluminescent lamp driver _______________________________________________________________________________________ 3 electrical characteristics (continued) (v dd = +2.4v to +5.5v, c lamp = 10nf, c cs = 3.3nf, l x = 220? (i sat = 170ma, r s = 5.5 ), t a = t min to t max , unless otherwise noted. typical values are at v dd = +3.0v and t a = +25?.) (note 1) parameter symbol conditions min typ max units boost converter v dd = +3v, dim = +0.5v forced externally 42 50 61 v dd = +3v, dim = +1v forced externally 85 100 115 output peak voltage v cs v dd = +3v, dim = +1.3v forced externally 105 125 140 v boost switching frequency f sw c sw = 96pf, r slew = 375k 80 100 120 khz switch on-resistance r lx i sink = 25ma, v dd = +3v 20 lx leakage current i lx v lx = +125v -1 +1 ? cs input current i cs no load, v cs = +125v, en = 0v, dim = 0v 50 ? control input sw input voltage-high threshold v ih_sw r slew = 375k 0.9 0.98 1.06 v input voltage-low threshold v il_sw r slew = 375k 0.43 0.49 0.55 v input low current i il_sw r slew = 375k , cs = +40v, el = v dd, dim = v dd 43 77 ? input high current i ih_sw r slew = 375k , cs = +40v, el = v dd , dim = v dd 5.0 7.5 ? control input el input voltage-high threshold v ih_cel r slew = 375k 1.08 1.32 v input voltage-low threshold v il_cel r slew = 375k 0.22 0.39 v input low current i il_cel r slew = 375k 1.2 1.87 ? input high current i ih_cel r slew = 375k 1.2 1.87 ? control input slew force voltage v force i source = 20? 0.89 0.95 1.04 v high-voltage output slew rate r slew = 375k 30 v/100? control input dim input logic-high voltage v ih_dim output voltage (max) 1.3 v input logic-low voltage v il_dim output voltage (off) 0.15 v input low current i il_dim v dim = 0v, r slew = 375k 2.22 3.0 ? input high current i ih_dim v dim = v dd -1 +1 ? pwm frequency range 0.2 to 1 mhz low-peak detector threshold v lpd 0.15 0.35 v low-peak detector hysteresis v lpd_hyst 100 mv control input en input voltage-high threshold v ih_en 1.2 v input voltage-low threshold v il_en 0.2 v input low current i il_en -1 +1 ? input high current i ih_en -1 +1 ?
MAX4990E high-voltage, 15kv esd-protected electroluminescent lamp driver 4 _______________________________________________________________________________________ 0 6 4 2 8 10 12 14 16 18 20 2.4 3.6 3.0 4.2 4.8 5.4 total input current vs. supply voltage MAX4990E toc01 supply voltage (v) total input current (ma) 0 4 12 8 16 20 -40 10 -15 35 60 85 total input current vs. temperature MAX4990E toc02 temperature ( c) total input current (ma) 80 60 40 20 0 40 120 80 160 200 total input current and peak-to-peak output voltage vs. boost converter frequency MAX4990E toc03 boost converter frequency (khz) total input current (ma) 300 225 150 75 0 peak-to-peak output voltage (v) - - - - peak-to-peak output voltage 90% duty cycle c cs = 4.7nf c cs = 2.2nf c cs = 2.2nf c cs = 4.7nf 0 0.2 0.6 0.4 0.8 1.0 2.4 3.6 3.0 4.2 4.8 5.4 shutdown current vs. supply voltage MAX4990E toc04 supply voltage (v) shutdown current (na) dim = en = 0v -40 10 -15 35 60 85 shutdown current vs. temperature MAX4990E toc05 temperature ( c) shutdown current (na) 10 1 0.1 0.01 100 dim = en = 0v 0 100 50 200 150 250 300 2.4 5.4 peak-to-peak output voltage vs. supply voltage MAX4990E toc06 supply voltage (v) peak-to-peak output voltage (v) 3.6 3.0 4.2 4.8 dim = 1.3v dim = 1.0v dim = 0.8v dim = 0.6v typical operating characteristics (v dd = +3.6v, c lamp = 10nf, c cs = 3.3nf, l x = 220? (i sat = 170ma, r s = 5.5 ), r slew = 390k , dim = v dd , c sw = 100pf, c el = 1.2nf, t a = +25?, unless otherwise noted.) electrical characteristics (continued) (v dd = +2.4v to +5.5v, c lamp = 10nf, c cs = 3.3nf, l x = 220? (i sat = 170ma, r s = 5.5 ), t a = t min to t max , unless otherwise noted. typical values are at v dd = +3.0v and t a = +25?.) (note 1) parameter symbol conditions min typ max units thermal shutdown thermal shutdown 158 ? thermal shutdown hysteresis 8c note 1: specifications at t a = -40? are guaranteed by design and not production.
MAX4990E high-voltage, 15kv esd-protected electroluminescent lamp driver _______________________________________________________________________________________ 5 180 190 185 200 195 205 210 -40 85 peak-to-peak output voltage vs. temperature MAX4990E toc07 temperature ( c) peak-to-peak output voltage (v) 10 -15 35 60 0 100 50 200 150 250 300 0.35 1.30 peak-to-peak output voltage vs. dim voltage MAX4990E toc08 dim voltage (v) peak-to-peak output voltage (v) 0.73 0.54 0.92 1.11 v dd = 4.5v 0 100 50 200 150 250 300 20 40 60 80 peak-to-peak output voltage vs. dim duty cycle MAX4990E toc09 dim duty cycle (%) peak-to-peak output voltage (v) f dim = 200khz f dim = 1mhz 0 40 20 80 60 100 120 2.4 5.4 rms output voltage vs. supply voltage MAX4990E toc10 supply voltage (v) rms output voltage (v) 3.6 3.0 4.2 4.8 -1000 -700 -800 -900 -600 -500 -400 -300 -200 -100 0 2.4 3.6 3.0 4.2 4.8 5.4 average output voltage vs. supply voltage MAX4990E toc11 supply voltage (v) average output voltage (mv) -1000 -700 -800 -900 -600 -500 -400 -300 -200 -100 0 -40 10 -15 35 60 85 average output voltage vs. temperature MAX4990E toc12 temperature ( c) average output voltage (mv) 0 100 300 200 400 500 el switching frequency vs.c el MAX4990E toc13 c el (nf) el switching frequency (hz) 0.5 1.5 1.0 2.0 2.5 r slew = 390k 190 185 180 175 170 2.4 3.6 3.0 4.2 4.8 5.4 el switching frequency vs. supply voltage MAX4990E toc14 supply voltage (v) el switching frequency (hz) 190 185 180 175 170 -40 10 -15 35 60 85 el switching frequency vs. temperature MAX4990E toc15 temperature ( c) el switching frequency (hz) typical operating characteristics (continued) (v dd = +3.6v, c lamp = 10nf, c cs = 3.3nf, l x = 220? (i sat = 170ma, r s = 5.5 ), r slew = 390k , dim = v dd , c sw = 100pf, c el = 1.2nf, t a = +25?, unless otherwise noted.)
MAX4990E high-voltage, 15kv esd-protected electroluminescent lamp driver 6 _______________________________________________________________________________________ 160 120 80 40 0 80 150 115 185 220 boost converter frequency vs. c sw MAX4990E toc16 c sw (pf) boost converter frequency (khz) r slew = 390k 110 105 100 95 90 2.4 3.6 3.0 4.2 4.8 5.4 boost converter frequency vs. supply voltage MAX4990E toc17 supply voltage (v) boost converter frequency (khz) 110 105 100 95 90 -40 -10 -15 35 60 85 boost converter frequency vs. temperature MAX4990E toc18 temperature ( c) boost converter frequency (khz) output voltage slope vs. r slew MAX4990E toc19 0 5 15 10 30 35 25 20 40 output voltage slope (v/100 s) 300 500 600 400 700 800 900 1000 r slew (k ) 22 24 28 26 30 32 2.4 3.6 3.0 4.2 4.8 5.4 output voltage slope vs. supply voltage MAX4990E toc20 supply voltage (v) output voltage slope (v/100 s) 22 24 28 26 30 32 -40 10 -15 35 80 85 output voltage slope vs. temperature MAX4990E toc21 temperature ( c) output voltage slope (v/100 s) 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 0 1.2 0.6 1.8 2.4 3.0 3.6 slow turn-on/-off time vs. c dim MAX4990E toc22 c dim ( f) slow turn on/off time (s) r dim = 390k t on t off 25 0 20 15 10 5 2.4 3.6 3.0 4.2 4.8 5.4 brightness and total input current vs. supply voltage MAX4990E toc23 supply voltage (v) brightness (cd/m 2 ) 30 22 18 14 26 10 total input current (ma) - - - - supply current c lamp = 20nf typical v a , v b , and v a - v b waveforms MAX4990E toc24 1ms/div v a - v b 100v/div v a 50v/div v b 50v/div typical operating characteristics (continued) (v dd = +3.6v, c lamp = 10nf, c cs = 3.3nf, l x = 220? (i sat = 170ma, r s = 5.5 ), r slew = 390k , dim = v dd , c sw = 100pf, c el = 1.2nf, t a = +25?, unless otherwise noted.)
detailed description the MAX4990E high-voltage dc-ac converter is ideal for driving el lamps. the MAX4990E features a wide +2.4v to +5.5v input range that allows the device to accept a wide variety of voltage sources such as sin- gle cell li+ batteries and higher voltage battery charg- ers. the lamp outputs of the device generate up to 250v peak-to-peak output voltage for maximum lamp brightness. the MAX4990E utilizes an inductor-based boost con- verter that allows for the use of a 220? inductor to gen- erate the high voltage necessary to drive an el lamp. the boost converter switching frequency is set with the combination of an external capacitor connected from the sw input to gnd and an external resistor connect- ed from slew to gnd. applying a pwm signal to the sw input allows the switching frequency of the boost converter to take the frequency of the pwm signal. the MAX4990E uses a high-voltage full-bridge output stage to convert the high voltage generated by the boost converter to an ac waveform suitable for driving the el panel. the el output switching frequency is set with the combination of an external capacitor connect- ed from el to gnd and an external resistor connected from slew to gnd. the MAX4990E allows programma- bility of the el lamp output frequency by applying a clock signal to the el input. applying a clock signal to the el input allows the switching frequency of the lamp to take the frequency of the clock signal divided by 4 to switch at the el input frequency divided by 4. the MAX4990E uses a proprietary acoustic noise- reduction circuit to control the slew rate of the ac volt- age, reducing audible noise from the el panel. the slew rate is set with an external resistor connected from slew to gnd. the MAX4990E enters a low-power shutdown mode (100na max) when en and dim inputs are connected MAX4990E high-voltage, 15kv esd-protected electroluminescent lamp driver _______________________________________________________________________________________ 7 pin description pin name function 1 slew high-voltage slew-rate control. connect an external resistor, r slew , to gnd to set the slew rate of the v a and v b high-voltage outputs. 2en enable input. drive en > +1.2v and dim > +0.35v to turn on the device. drive en < +0.2v and dim < +0.15v to turn off the device. 3 dim el panel dimming control. apply a pwm signal or dc analog control signal, or connect a resistor to gnd to adjust peak-to-peak output voltage. use dim together with en to control device shutdown (see shutdown section). 4el el voltage switching frequency. connect an external capacitor, c el , to gnd or drive with an external oscillator to set the switching frequency of the v a and v b high-voltage outputs. connect el to gnd to shut off the el oscillator. drive el high to keep alternatively v a or v b output high. 5sw boost-converter switching frequency. connect an external capacitor, c sw , to gnd or drive with an external oscillator to set the switching frequency of the boost converter. connect sw to gnd to shut off the boost oscillator. do not keep sw high to avoid lx shorting to gnd, which causes the internal die temperature to increase. the MAX4990E is protected by entering a themal-shutdown state. (see the thermal short-circuit protection section.) 6v dd power-supply voltage 7 gnd ground 8lx internal switching dmos drain connection. connect lx to a switching inductor and an anode of a rectifying diode. 9, 11, 13 n.c. no connection. leave n.c. unconnected. 10 cs high-voltage supply. connect cs to output capacitor of boost converter. 12 v b high-voltage el panel output. connect to non-v a side of el lamp. 14 v a high-voltage el panel output. connect to non-v b side of el lamp. ep ep exposed pad. connect exposed pad to gnd.
MAX4990E to gnd. the MAX4990E also enters thermal shutdown if the die temperature rises above +158?. the MAX4990E features an el lamp dimming control (dim) that allows the user to set the el output voltage with a pwm, dc analog voltage, or a resistor connect- ed to gnd. a capacitor placed in parallel to the resistor on the dim input allows the user to program a slow turn-on/-off time of the MAX4990E? outputs to generate a soft fade-on/fade-off effect of the el lamp. the high-voltage outputs are esd protected up to ?5kv human body model, ?5kv air-gap discharge, and ?kv contact discharge, as specified in the iec 61000-4-2 specification. el output voltage the slew rate, frequency, and peak-to-peak voltage of the MAX4990E el lamp outputs are programmed through a combination of external components and/or dc inputs. the device uses resistor r slew to set the bias current used as a reference current for the MAX4990E internal circuitry. the reference current directly affects the slew rate of the el lamp output. increasing the value of r slew decreases the slew rate, and decreasing the value of r slew increases the slew rate. (see the r slew resistor selection section on how to select r slew .) the MAX4990E el lamp output frequency uses an internal el oscillator to set the desired frequency. the output frequency is adjusted by either 1) the combina- tion of a resistor from slew to gnd and an external capacitor from the el input to gnd, or 2) by driving a clock signal directly into the el input. (see the c el capacitor selection section for choosing the c el capacitor value.) the peak-to-peak voltage of the el lamp output is var- ied from 70v p-p to 250v p-p by applying an external dc voltage ranging from +0.35v to +1.3v to the dim input. high-voltage, 15kv esd-protected electroluminescent lamp driver 8 _______________________________________________________________________________________ +- -+ switch oscillator v dd sw lx cs v a v b el slew en dim gnd timeout el oscillator v-i converter high esd protection h-bridge high esd protection dmos driver ref n v sense low-power shutdown low peak detector low-power shutdown shutdown no-operation signal timeout pwm converter thermal shutdown uvlo MAX4990E functional diagram
increasing the voltage on the dim input increases the peak-to-peak voltage, and decreasing the voltage on the input decreases the peak-to-peak voltage. the el lamp peak-to-peak voltage is also adjusted by applying a pwm signal to the dim input. the duty cycle of the pwm determines the el lamp output peak-to-peak volt- age. as the duty cycle is increased, the peak-to-peak output voltage is increased, and as the duty cycle is decreased, the peak-to-peak voltage is decreased. the MAX4990E also features a slow turn-on and slow turn-off time feature that is enabled by connecting a resistor and capacitor from dim to gnd (see the typical application circuits and the r dim resistor and c dim capacitor selection section). this slow turn-on/-off feature causes the peak-to-peak voltage of the el outputs to slowly rise from zero to the maximum set value when the device is enabled. this feature also causes the peak-to-peak volt- age of the el outputs to fall from the maximum set value to zero when the device is placed into shutdown. the slow rise and fall of the peak-to-peak el output voltage creates a soft fade-on and fade-off of the el lamp, rather than an abrupt change in brightness. boost converter the MAX4990E boost converter consists of an external inductor from v dd to the lx input, an internal dmos switch, an external diode from lx to the cs output, an external capacitor from the cs output to gnd, and the el lamp, c lamp , connected to the el lamp outputs. when the dmos switch is turned on, lx is connected to gnd, and the inductor is charged. when the dmos switch is turned off, the energy stored in the inductor is transferred to the capacitor c cs and the el lamp. note: keeping sw high shorts lx to gnd, causing the internal die temperature to increase. the MAX4990E is protected by entering a thermal-shutdown state (see the thermal short-circuit protection section.) the MAX4990E boost converter frequency uses an internal switch oscillator to set the desired frequency of the boost converter. the boost converter frequency is adjusted by either 1) the combination of a resistor from slew to gnd and an external capacitor from sw to gnd, or 2) by driving a pwm signal directly into the sw input. when sw is driven with an external pwm signal at a suggested 90% duty cycle, the boost converter fre- quency is changed to the frequency of the external pwm signal. (see the c sw capacitor selection section for choosing the c sw capacitor value.) dimming control the MAX4990E features a dimming control input, dim, that controls the peak-to-peak voltage on the lamp out- puts v a and v b . dim is controlled by a resistor con- nected from the dim input to gnd, a pwm signal applied to the dim input, or a dc voltage applied to the dim input. (see the r dim resistor and c dim capacitor selection section.) the duty cycle of a pwm signal to the dim input is internally translated into a dc voltage with the 0 to +1.22v range. the dim input accepts the frequency range of 200khz to 1mhz. as the duty cycle increases, the peak-to-peak voltage of the output increases, and as the duty cycle decreases, the peak-to-peak voltage of the output decreases. the peak-to-peak voltage is adjusted by applying a dc voltage to the dim input. increasing the voltage on dim increases the peak-to-peak output, and decreasing the voltage on dim decreases the peak-to-peak output voltage. the dim input, in combination with the en input, con- trols the shutdown mode of the MAX4990E shutdown. (see the shutdown section.) slow turn-on, slow turn-off the MAX4990E provides a slow turn-on/-off feature by connecting a resistor in parallel with a capacitor con- nected from the dim input to gnd (see the r dim resistor and c dim capacitor selection section). when en is driven high, the reference current i b (set by r slew ) is used to charge capacitor c dim . when en is driven to gnd, i b is removed, and the voltage on the capacitor c dim and resistor decays with a time con- stant of r dim x c dim . a slow turn-on effect is seen by driving en high. the slow rise and fall of the voltage on dim during transitions on the en input modulates the peak-to-peak voltage of the el outputs, creating a soft fade-on/-off effect at the el lamp. shutdown the MAX4990E features an enable logic input, en, to enable and disable the device. to enable the device, apply +1.2v or greater to the en input and +0.35v or greater to the dim input. to place the device in shut- down, apply +0.2v or less to the en input, and +0.15v or less to the dim input. undervoltage lockout (uvl0) the MAX4990E has a uvlo threshold of +2.1v (typ). when v dd falls below +2.1v (typ), the device enters a nonoperative mode. thermal short-circuit protection the MAX4990E enters a nonoperative mode if the inter- nal die temperature of the device reaches or exceeds +158? (typ). the device turns back on when the inter- nal die temperature cools to +150?. MAX4990E high-voltage, 15kv esd-protected electroluminescent lamp driver _______________________________________________________________________________________ 9
MAX4990E 15kv esd protection as with all maxim devices, esd-protection structures are incorporated on all pins to protect against electro- static discharges encountered during handling and assembly. the el lamp driver outputs of the MAX4990E have extra protection against static electricity. maxim? engineers have developed state-of-the-art structures to protect these pins against esd of ?5kv without dam- age. the esd structures withstand high esd in all states: normal operation, shutdown, and powered down. after an esd event, the MAX4990E keep working without latchup or damage. esd protection can be tested in various ways. the transmitter el lamp outputs of the MAX4990E are char- acterized for protection to the following limits: ? ?5kv using the human body model ? ?kv iec 61000-4-2 contact discharge ? ?5kv iec 61000-4-2 air-gap discharge esd test conditions esd performance depends on a variety of conditions. contact maxim for a reliability report that documents test setup, test methodology, and test results. human body model figure 1a shows the human body model, and figure 1b shows the current waveform it generates when dis- charged into a low impedance. this model consists of a 100pf capacitor charged to the esd voltage of inter- est, which is then discharged into the test device through a 1.5k resistor. iec 61000-4-2 the iec 61000-4-2 standard covers esd testing and performance of finished equipment. however, it does not specifically refer to integrated circuits. the MAX4990E assists in designing equipment to meet iec 61000-4-2 without the need for additional esd-protec- tion components. the major difference between tests done using the human body model and iec 61000-4-2 is higher peak current in iec 61000-4-2 because series resistance is lower in the iec 61000-4-2 model. hence, the esd withstand voltage measured to iec 61000-4-2 is gener- ally lower than that measured using the human body model. figure 1c shows the iec 61000-4-2 model, and figure 1d shows the current waveform for iec 61000-4- 2 esd contact discharge test. machine model the machine model for esd tests all pins using a 200pf storage capacitor and zero discharge resistance. the objective is to emulate the stress caused when i/o pins are contacted by handling equipment during test and assembly. of course, all pins require this protection. the air-gap test involves approaching the device with a charged probe. the contact discharge method connects the probe to the device before the probe is energized. design procedure l x inductor selection the recommended inductor values are 220?/330?. for most applications, series resistance (dcr) should be below 8 for reasonable efficiency. do not exceed the inductor? saturation current. r slew resistor selection to help reduce audible noise emission by the el lamp, the MAX4990E features a slew-rate control input (slew) that allows the user to set the slew-rate of the high-voltage outputs, v a and v b, by connecting a resistor, r slew , from the slew input to gnd. r slew precisely sets the reference current i b that is used to charge and discharge the capacitances at the sw input and el input, and is used as a reference current for internal circuitry. the reference current is related to r slew by the following equation: i b = 1v/r slew . decreasing the value of r slew increases i b and increases the slew rate at the el lamp output. increasing the value of r slew decreases i b and decreases the slew rate at the el lamp output. the output slew rate is related to r slew by the following equation: the ideal value for a given design varies depending on lamp size and mechanical enclosure. typically, the best slew rate for minimizing audible noise is between 10v/100? and 20v/100?. this results in r slew values ranging from 1.125m to 0.5625m . for example, if the desired slew rate is 20 (v/100?), this leads to an r slew resistor value in m of r slew = 11.25/20v = 0.5625m . note: connecting r slew to gnd will not damage the device. however, for the device to operate correctly, r slew should be in the 100k to 2.2m range. r slew also affects the frequency of the boost converter (see the c sw capacitor selection ), the frequency of the el lamp (see the c el capacitor selection section), and the peak-to-peak voltage of the el lamp. slewrate v sr m 100 125 ? ? ? ? ? ? = () 1 slew . high-voltage, 15kv esd-protected electroluminescent lamp driver 10 ______________________________________________________________________________________
the peak-to-peak voltage is adjusted by connecting a resistor from the slew input to gnd together with a resistor from the dim input to gnd. the equation relating the peak-to-peak voltage to the resistors is the following: r dim resistor and c dim capacitor selection the MAX4990E provides a slow turn-on/-off feature by connecting a resistor in parallel with a capacitor con- nected from the dim input to gnd. the reference cur- rent i b is used to charge the resistor and capacitor. when en is driven to gnd, i b is removed, and the volt- age across the capacitor and resistor decay with a time constant of rc that provides a slow turn off of the el v r r p-p dim slew = 200 MAX4990E high-voltage, 15kv esd-protected electroluminescent lamp driver ______________________________________________________________________________________ 11 charge-current- limit resistor discharge resistance storage capacitor c s 100pf r c 1m r d 1500 high- voltage dc source device under test figure 1a. human body esd test model i p 100% 90% 36.8% t rl time t dl current waveform peak-to-peak ringing (not drawn to scale) i r 10% 0 0 amps figure 1b. human body current waveform charge-current- limit resistor discharge resistance storage capacitor c s 150pf r c 50m to 100m r d 330 high- voltage dc source device under test figure 1c. iec 61000-4-2 esd test model t r = 0.7ns to 1ns 30ns 60ns t 100% 90% 10% i peak i figure 1d. iec 61000-4-2 esd generator current waveform table 1. inductor vendors inductor value (?) vendor website part 220 toko www.tokoam.com d312c 1001bs-221m 330 coilcraft www.coilcraft.com do1608c-334ml 470 coilcraft www.coilcraft.com do1608c-474ml 220 coilcraft www.coilcraft.com lps4018-224ml 330 coilcraft www.coilcraft.com lps4018-334ml 470 coilcraft www.coilcraft.com lps4018-474ml
MAX4990E lamp outputs. a slow turn-on effect is produced by dri- ving en high. slow turn-on/-off time is related by the fol- lowing equation: t on = 2.6 x r dim x c dim t off = 1.2 x r dim x c dim for this equation to be valid, r dim /r slew must be 1.3. c cs capacitor selection c cs is the output of the boost converter and provides the high-voltage source for the el lamp. connect a 3.3nf capacitor from cs to gnd and place as close to the cs input as possible. when using an inductor value larger than 220?, it may be necessary to increase the c cs . for a lx = 470? and c lamp = 20nf, a c cs ranging from 3.3nf to 6.8nf is recommended. c el capacitor selection the MAX4990E el lamp output frequency is set by connecting a capacitor from the el input to gnd together with a resistor from slew to gnd or by driving the el input with an external clock (0 to +1.5v). the el lamp output frequency is related to the c el capacitor by the following equation: for example, an r slew = 375k and a c el capacitor value of 1000pf equals an el lamp output frequency of f el = 217hz. c sw capacitor selection the boost converter switching frequency is set by con- necting a capacitor from the sw input to gnd, together with the resistance from the slew input to gnd, or driving the sw input with an external clock (0 to +1.5v). the switching frequency of the boost converter is related to the capacitor from sw to gnd by the following equation: connect the sw input to gnd to turn the switch oscilla- tor of the boost converter off. although the optimal f sw depends on the inductor value, the suggested f sw range is 20khz to 150khz. note: driving sw with a logic-high causes lx to be dri- ven to gnd. keeping sw high shorts lx to gnd, caus- ing the internal die temperature to increase. the MAX4990E is protected by entering a thermal-shutdown state. (see the thermal short-circuit protection section.) c b capacitor selection bypass v dd with a 0.1? ceramic capacitor as close to the ic as possible and a 4.7? ceramic capacitor as close to the inductor as possible diode selection connect a diode, d 1 , from the lx node to cs to rectify the boost voltage on cs. the diode should be a fast- recovery diode that is tolerant to +150v. el lamp selection el lamps have a capacitance of approximately 2.5nf to 3.5nf per square inch. the MAX4990E effectively charges capacitance ranging from 2nf to 20nf. applications information pcb layout keep pcb traces as short as possible. ensure that bypass capacitors are as close to the device as possi- ble. use large ground planes where possible. chip information process: bicmos-dmos f rc sw slew sw = 361 . f rc el slew el = 0 0817 . high-voltage, 15kv esd-protected electroluminescent lamp driver 12 ______________________________________________________________________________________
MAX4990E high-voltage, 15kv esd-protected electroluminescent lamp driver ______________________________________________________________________________________ 13 MAX4990E slew digital output pwm or v bias c or asic r slew l x = 220 h v dd 14 12 13 1 v a n.c. v b en el lamp c lamp = 10nf dim el 11 n.c. sw c el c sw 10 d 1 c cs = 3.3nf c b = 0.1 f cs v dd 9 n.c. gnd 8 3 2 4 5 6 7 lx 4.7 f MAX4990E slew digital output c or asic r slew r dim c dim l x = 220 h v dd 14 12 13 1 v a n.c. v b en el lamp c lamp = 10nf dim el 11 n.c. sw c el c sw 10 d 1 c cs = 3.3nf c b = 0.1 f cs v dd 9 n.c. gnd 8 3 2 4 5 6 7 lx 4.7 f typical application circuits
MAX4990E high-voltage, 15kv esd-protected electroluminescent lamp driver 14 ______________________________________________________________________________________ 6, 8, &10l, dfn thin.eps package information (the package drawing(s) in this data sheet may not reflect the most current specifications. for the latest package outline info rmation, go to www.maxim-ic.com/packages .)
MAX4990E high-voltage, 15kv esd-protected electroluminescent lamp driver maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circu it patent licenses are implied. maxim reserves the right to change the circuitry and specifications without notice at any time. maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 ____________________ 15 2007 maxim integrated products is a registered trademark of maxim integrated products, inc. springer common dimensions symbol min. max. a 0.70 0.80 d 2.90 3.10 e 2.90 3.10 a1 0.00 0.05 l 0.20 0.40 pkg. code n d2 e2 e jedec spec b [(n/2)-1] x e package variations 0.25 min. k a2 0.20 ref. 2.00 ref 0.250.05 0.50 bsc 2.300.10 10 t1033-1 2.40 ref 0.200.05 - - - - 0.40 bsc 1.700.10 2.300.10 14 t1433-1 1.500.10 mo229 / weed-3 0.40 bsc - - - - 0.200.05 2.40 ref t1433-2 14 2.300.10 1.700.10 t633-2 6 1.500.10 2.300.10 0.95 bsc mo229 / weea 0.400.05 1.90 ref t833-2 8 1.500.10 2.300.10 0.65 bsc mo229 / weec 0.300.05 1.95 ref t833-3 8 1.500.10 2.300.10 0.65 bsc mo229 / weec 0.300.05 1.95 ref 2.300.10 mo229 / weed-3 2.00 ref 0.250.05 0.50 bsc 1.500.10 10 t1033-2 package information (continued) (the package drawing(s) in this data sheet may not reflect the most current specifications. for the latest package outline info rmation, go to www.maxim-ic.com/packages .)

▲Up To Search▲

Price & Availability of MAX4990E

	To Download MAX4990E Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .