general description the max4987ae/max4987be are overvoltage protection devices with built-in esd protection for usb data lines. these devices feature a low 100m (typ) r on internal nfet switch and protect low-voltage systems against volt- age faults up to +28v. when the input voltage exceeds the overvoltage threshold or decreases below the under- voltage threshold, the internal nfet switch is turned off to prevent damage to the protected components. all switches feature a minimum 1.5a current-limit pro- tection. during a short-circuit occurrence, the switch operates in an autoretry mode where the internal nfet switch is turned on to check if the fault has been removed. the autoretry interval is 30ms, and if the fault is removed, the nfet switch remains on. the max4987ae/max4987be feature low-capacitance (3pf) esd protection for usb data lines that allow transmission of high-speed usb 2.0 signals. the overvoltage threshold (ovlo) is preset to 6.15v. the undervoltage thresholds (uvlo) are preset to 2.55v (max4987ae) or 4.2v (max4987be). when the input voltage drops below the undervoltage (uvlo) thresh- old, the devices enter a low-current standby mode. all devices are offered in a small 2mm x 3mm, 8-pin tdfn package and operate over the -40? to +85? extended temperature range. applications cell phones media players features input voltage protection up to +28v integrated low r on (100m ) nfet switch internal overcurrent protection 1.5a (min) overcurrent protection (autoretry) enable input internal 30ms startup delay low-capacitance usb high-speed data line esd protection (3pf) ?5kv human body model ?5kv iec 61000-4-2 air gap ?kv iec 61000-4-2 contact thermal-shutdown protection 2mm x 3mm, 8-pin tdfn package max4987ae/max4987be overvoltage-protection controller with usb esd protection ________________________________________________________________ maxim integrated products 1 ordering information/selector guide 19-1059; rev 0; 11/07 for pricing, delivery, and ordering information, please contact maxim direct at 1-888-629-4642, or visit maxim? website at www.maxim-ic.com. note: all devices are specified over the -40? to +85? operating temperature range. + denotes a lead-free package. * future product? ontact factory for availability. ** ep = exposed paddle. typical operating circuit appears at end of data sheet. part pin- package top mark package code uvlo (v) ovlo (v) overcurrent mode max4987ae eta+ 8 tdfn-ep** aai t823-1 2.55 6.15 autoretry max4987be eta+* 8 tdfn-ep** aaj t823-1 4.2 6.15 autoretry pin configuration 134 865 out v cc max4987ae/ max4987be 2 7 in *connect exposed pad to gnd. gnd cd- cd+ tdfn-ep 2mm x 3mm top view en acok *ep
max4987ae/max4987be overvoltage-protection controller with usb esd protection 2 _______________________________________________________________________________________ absolute maximum ratings electrical characteristics (v in = +2.2v to +28v, t a = -40? to +85?, unless otherwise noted. typical values are at v in = +5v and t a = +25?.) 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.) in ............................................................................-0.3v to +30v out.............................................................-0.3v to +(in + 0.3v) v cc , en , acok , cd+, cd- ......................................-0.3v to +6v continuous power dissipation (t a = +70?) for multilayer board: 8-pin tdfn (derate 16.7mw/? above +70?) .........1333mw package junction-to-ambient thermal resistance ( ja ) (note 1) ................................................................60.0?/w package junction-to-case thermal resistance ( jc ) (note 1) ................................................................10.8?/w operating temperature range ...........................-40? to +85? junction temperature ......................................................+150? storage temperature range .............................-65? to +150? lead temperature (soldering) .........................................+300? parameter symbol conditions min typ max unit analog switch input-voltage range v in 2.2 28 v v cc input voltage v cc 5.5 v en = 0v, v in > v uvlo 60 150 input supply current i in en = 5v, v in > v uvlo 50 100 ? uvlo supply current i uvlo v in < v uvlo 40 ? max4987ae 2.3 (v in falling) max4987be 3.8 max4987ae 2.35 2.55 2.75 in undervoltage lockout v uvlo (v in rising) max4987be 3.85 4.2 4.45 v in undervoltage lockout hysteresis 1% (v in rising) 5.55 6.15 6.45 overvoltage trip level v ovlo (v in falling) 5.5 v in overvoltage lockout hysteresis 1% switch on-resistance r on v in = 5v, i out = 500ma 100 200 m overcurrent protection threshold i lim 1.5 4.2 a maximum output capacitance v in = 5v, no overcurrent shutdown 1000 ? cd+ and cd- leakage current i lkg_cd v cc = 5.5v, v cd_ = 0v, 3.3v -300 +300 na cd+ and cd- capacitance c cd f = 1mhz, v cd_ = 0.5 p-p 3pf digital signals acok output low voltage v ol i sink = 1ma 0.4 v acok high-leakage current v acok = 5.5v, flag deasserted 1 ? en input-voltage high v ih 1.4 v en input-voltage low v il 0.4 v en input-leakage current i leak v en = 5.5v -1 +1 ? note 1: package thermal resistances were obtained using the method described in jedec specification jesd51-7, using a 4-layer board. for detailed information on package thermal considerations, go to www.maxim-ic.com/thermal-tutorial .
max4987ae/max4987be overvoltage-protection controller with usb esd protection _______________________________________________________________________________________ 3 note 2: all timing is specified using 20% and 80% levels, unless otherwise noted. electrical characteristics (continued) (v in = +2.2v to +28v, t a = -40? to +85?, unless otherwise noted. typical values are at v in = +5v and t a = +25?.) parameter symbol conditions min typ max unit timing characteristics (note 2) debounce time t indbc time from v uvlo < v in < v ovlo to charge-pump enable 30 ms acok assertion time t acok v uvlo < v in < v ovlo , to acok low 30 ms switch turn-on time t on v uvlo < v in < v ovlo , r load = 100 , from 10% to 90% of v out 3ms switch turn-off time t off v in < v uvlo or v in > v ovlo to internal switch off, r load = 100 10 ? current-limit turn-off time t blank overcurrent fault to internal switch off 10 ? autoretry time t retry from overcurrent fault to internal switch turn-on 30 ms thermal protection thermal shutdown t shdn 150 ? thermal-shutdown hysteresis 40 ? esd protection human body model ?5 iec 61000-4-2 air gap ?5 cd+ and cd- iec 61000-4-2 contact ? kv all other pins human body model ? kv in supply current vs. in voltage max4987ae/be toc01 0 10 30 20 60 70 50 40 80 in supply current ( a) 21014 6 18 22 26 in voltage (v) max4987ae 0 60 40 20 80 100 120 140 160 180 200 -40 10 -15 35 60 85 switch on-resistance vs. temperature max4987ae/be toc02 temperature ( c) r on (m ) 0.990 0.996 0.994 0.992 0.998 1.000 1.002 1.004 1.006 1.008 1.010 -40 10 -15 356085 normalized uvlo threshold vs. temperature max4987ae/be toc03 temperature ( c) normalized uvlo threshold (v) typical operating characteristics (t a = +25?, unless otherwise noted.)
max4987ae/max4987be overvoltage-protection controller with usb esd protection 4 _______________________________________________________________________________________ typical operating characteristics (continued) (t a = +25?, unless otherwise noted.) 0.990 0.996 0.994 0.992 0.998 1.000 1.002 1.004 1.006 1.008 1.010 -40 10 -15 356085 normalized ovlo threshold vs. temperature max4987ae/be toc04 temperature ( c) normalized ovlo threshold (v) 0.80 0.92 0.88 0.84 0.96 1.00 1.04 1.08 1.12 1.16 1.20 -40 10 -15 356085 normalized current limit vs. temperature max4987ae/be toc05 temperature ( c) current limit (%) 0 2.0 1.0 3.0 4.0 5.0 -40 85 turn-on time vs. temperature max4987ae/be toc06 temperature ( c) turn on time (ms) 10 -15 35 60 20.0 30.0 25.0 40.0 35.0 45.0 50.0 -40 85 debounce time vs. temperature max4987ae/be toc07 temperature ( c) debounce time (ms) 10 -15 35 60 undervoltage fault response max4987ae/be toc10 4 s/div v in 2v/div 5 2 0 0 0 v out 2v/div i out 1a/div v acok 5v/div power-up response max4987ae/be toc08 10ms/div v in 5v/div v out 5v/div i out 1a/div v acok 5v/div overvoltage fault response max4987ae/be toc09 2 s/div v in 5v/div 8v 5v 8v 5v 0 0 0 v out 5v/div i out 1a/div v acok 5v/div short-circuit fault response max4987ae/be toc11 10 s/div v in 5v/div 0 0 0 0 v out 5v/div i out 1a/div v acok 5v/div c in = 100 f
max4987ae/max4987be overvoltage-protection controller with usb esd protection _______________________________________________________________________________________ 5 pin description pin name function 1in voltage input. bypass in with a 1? ceramic capacitor as close to the device as possible to obtain ?5kv hbm esd protection. no capacitor required to obtain ?kv hbm esd protection. 2 cd+ usb data line 3 gnd ground 4 cd- usb data line 5v cc positive supply-voltage input. v cc is required only when usb signals are present. 6 en enable active-low input. drive en low to enable the switch. drive en high to disable the switch. 7 acok open-drain adapter-voltage indicator output. acok is driven low after the v in voltage is stable between uvlo and ovlo for 30ms (typ). connect a pullup resistor from acok to the logic i/o voltage of the host system. 8 out output voltage. output of internal switch. ep ep exposed pad. connect exposed pad to ground. do not use ep as a sole ground connection. overcurrent fault in cd+ cd- v cc charge pump control logic max4987ae/ max4987be acok v bg reference + - + - ov uv en en out gnd functional diagram
max4987ae/max4987be detailed description the max4987ae/max4987be are overvoltage protec- tion devices with integrated esd protection for usb data lines. these devices feature a low r on internal fet and protect low-voltage systems against voltage faults up to +28v. if the input voltage exceeds the over- voltage threshold, the internal nfet switch is turned off to prevent damage to the protected components. the 30ms debounce time prevents false turn-on of the inter- nal nfet switch during startup. an open-drain active- low logic output is available to signal that a successful power-up has occurred. device operation the max4987ae/max4987be have an internal oscilla- tor and charge pump that control the turn-on of the internal nfet switch. the internal oscillator controls the timers that enable the turn-on of the charge pump and controls the state of the open-drain acok output. if v in < v uvlo or if v in > v ovlo , the internal oscillator remains off, thus disabling the charge pump. if v uvlo < v in < v ovlo , the internal charge pump is enabled. the charge-pump startup, after a 30ms internal delay, turns on the internal nfet switch and asserts acok (see figure 1). at any time, if v in drops below v uvlo or rises above v ovlo , acok is pulled high and the charge pump is disabled. internal nfet switch the max4987ae/max4987be incorporate an internal nfet switch with a 100m (typ) on-resistance. the nfet switch is internally driven by a charge pump that generates a voltage above the input voltage. the max4987ae/max4987be is equipped with a 1.5a (min) current-limit protection that turns off the nfet switch within 5? (typ) during an overcurrent fault condition. autoretry the max4987ae/max4987be have an overcurrent autoretry function that turns on the nfet switch again after a 30ms (typ) retry time (see figure 2). if the faulty load condition is still present after the blanking time, the switch turns off again and the cycle is repeated. the fast turn-off time and 30ms retry time result in a very low duty cycle in order to keep power consumption low. if the faulty load condition is not present, the switch remains on. undervoltage lockout (uvlo) the max4987ae has a 2.55v undervoltage-lockout threshold (uvlo), while the max4987be has a 4.15v uvlo threshold. when v in is less than v uvlo , acok is high impedance. overvoltage-protection controller with usb esd protection 6 _______________________________________________________________________________________ uvlo ovlo t indbc t on in out acok t indbc t off 90% v out t indbc t off 10% v out figure 1. max4987ae/max4987be timing diagram
overvoltage lockout (ovlo) the max4987ae/max4987be have a 6.15v (typ) over- voltage threshold (ovlo). when v in is greater than v ovlo , acok is high impedance. acok acok is an active-low open-drain output that asserts low when v uvlo < v in < v ovlo following the 30ms (typ) debounce period. connect a pullup resistor from acok to the logic i/o voltage of the host system. during a short-circuit fault, acok may deassert due to v in not being in the valid operating voltage range. thermal-shutdown protection the max4987ae/max4987be feature thermal-shutdown circuitry. the internal nfet switch turns off when the junction temperature exceeds t shdn and immediately goes into a fault mode. the device exits thermal shut- down after the junction temperature cools by +40? (typ). applications information in bypass capacitor for most applications, bypass in to gnd with a 1? ceramic capacitor as close to the device as possible to enable ?5kv hbm esd protection on in. if ?5kv hbm esd protection is not required, there is no capacitor required at in. if the power source has significant induc- tance due to long lead length, take care to prevent over- shoots due to the lc tank circuit and provide protection if necessary to prevent exceeding the absolute maximum rating on in. esd test conditions esd performance depends on a number of conditions. the max4987ae/max4987be are specified for ?5kv hbm esd protection on the cd+, cd-, and in pins when in is bypassed to ground with a 1? ceramic capacitor. the cd+ and cd- inputs are also protected against ?5kv air gap and ?kv contact iec 61000-4- 2 esd events. human body model figure 3 shows the human body model, and figure 4 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, that is then discharged into the device through a 1.5k resistor. iec 61000-4-2 the iec 61000-4-2 standard covers esd testing and per- formance of finished equipment. it does not specifically refer to integrated circuits. the max4987ae/ max4987be max4987ae/max4987be overvoltage-protection controller with usb esd protection _______________________________________________________________________________________ 7 nfet switch on nfet switch on switch off current through nfet switch i lim t off t retry figure 2. autoretry timing diagram charge current- limit resistor discharge resistance storage capacitor c s 100pf r c 1m r d 1.5k high- voltage dc source device under test figure 3. 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 amperes figure 4. human body current waveform
max4987ae/max4987be are specified for ?5kv air-gap discharge and ?kv contact discharge iec 61000-4-2 on the cd+ and cd- pins. the major difference between tests done using the human body model and iec 61000-4-2 is a higher peak current in iec 61000-4-2, due to lower series resistance. hence, the esd withstand voltage measured to iec 61000-4-2 generally is lower than that measured using the human body model. figure 5 shows the iec 61000- 4-2 model. the contact discharge method connects the probe to the device before the probe is charged. the air-gap discharge test involves approaching the device with a charged probe. overvoltage-protection controller with usb esd protection 8 _______________________________________________________________________________________ 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 5. iec 61000-4-2 esd test model overcurrent fault in cd+ cd- out v cc charge pump control logic max4987ae/ max4987be acok v io phone load v bg reference + - + - ov uv en usb connector vbus d+ d- usb transceiver v cc d+ d- gnd v cc battery charger typical operating circuit chip information process: bicmos
max4987ae/max4987be overvoltage-protection controller with usb esd protection _______________________________________________________________________________________ 9 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 .) 8l, tdfn.eps package outline 21-0174 2 1 b 8l tdfn, exposed pad, 2x3x0.8mm
max4987ae/max4987be overvoltage-protection controller with usb esd protection 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. 10 ____________________maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 2007 maxim integrated products is a registered trademark of maxim integrated products, inc. springer 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 .) symbol dimensions 3.00 2.95 0.75 nom. 0.70 min. 0.20 ref. 0.40 0.02 2.00 0.30 0.00 1.95 e a l a1 d a2 k 0.20 min. package outline 21-0174 2 2 b 8l tdfn, exposed pad, 2x3x0.8mm 8 n 3.05 0.80 max. 0.50 0.05 2.05 0.50 bsc e b 0.25 0.18 0.30 1.60 min. 1.75 nom. 1.90 max. e2 1.50 min. 1.63 nom. 1.75 max. d2 t823-1 pkg. code exposed pad package
|
