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general description the max1564 triple, current-limited usb switch comes in a space-saving, 16-pin, 4mm x 4mm thin qfn pack- age. each channel meets all iec specifications for usb ports. the device is capable of supplying up to 1.2a from each output. the max1564 has multiple protection features, including thermal shutdown to limit junction temperature in case of a prolonged short or overload condition. reverse-current protection circuitry blocks current flow from output to input regardless of the switch state. the ic has accurate, user-programmable current-limiting circuitry to protect the input supply against overload. each output of the max1564 has short-circuit protec- tion that latches off the switch when the output is short- ed for more than 20ms, thereby saving system power. auto-restart then tests the shorted output with a 25ma current to determine when the short is removed, then automatically restarts the output. independent open- drain fault signals notify the microprocessor that the internal current limit has been reached. a 20ms fault- blanking feature allows momentary faults to be ignored, such as those caused when hot-swapping into a capacitive load. this feature helps avoid issuing false alarms to the host system. blanking also suppresses errant fault signals when the device is powering up. applications usb ports usb hubs notebook computers desktop computers docking stations features ? tiny 16-pin 4mm x 4mm thin qfn package ? reverse-current blocking ? programmable current limit ? auto-restart when fault is removed ? 12% accurate current limit ? up to 1.2a load current for each output ? thermal-overload protection ? built-in 20ms fault blanking ? compliant with all usb specifications ? 2.7v to 5.5v input supply range ? independent fault indicator outputs ? active-high/active-low select pin ? 15kv esd protection (with caps) ? ul listing pending max1564 triple 1.2a usb switch in 4mm x 4mm thin qfn ________________________________________________________________ maxim integrated products 1 13 14 15 16 12 4 9 10 11 12 onc top view onb ona ina v cc inb inc outa gnd outb outc thin qfn 4mm x 4mm fltc fltb sel seti 8 7 6 5 3 max1564 flta pin configuration ordering information 19-3463; rev 0; 11/04 for pricing, delivery, and ordering information, please contact maxim/dallas direct! at 1-888-629-4642, or visit maxim? website at www.maxim-ic.com. evaluation kit available part temp range pin-package pkg code MAX1564ETE -40? to +85? 16 thin qfn-ep* 4mm x 4mm t1644-4 * ep = exposed pad.
max1564 triple 1.2a usb switch in 4mm x 4mm thin qfn 2 _______________________________________________________________________________________ absolute maximum ratings 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. in_, on_, out_, sel, v cc to gnd (note 1)............-0.3v to +6v flt_ , seti to gnd .....................................-0.3v to (v cc + 0.3v) in_ to out_ (when disabled, note 2) .........................-6v to +6v in_ to out_ (when enabled, note 3)....................-1.5a to +2.3a flt_ sink current................................................................20ma continuous power dissipation 16-pin 4mm x 4mm thin qfn (derate 16.9mw/? above +70?) .............................1349mw operating temperature range ...........................-40? to +85? junction temperature ......................................................+150? storage temperature range .............................-65? to +150? lead temperature (soldering, 10s) ................................+300? electrical characteristics (v in_ = v cc = v sel = v on_ = 5v, r seti = 26.1k ? , t a = -40? to +85?, unless otherwise noted. typical values are at t a = +25?.) (note 4) note 1: ina, inb, inc, and v cc must be connected together externally. note 2: reverse current (current from out_ to in_) is blocked when disabled. note 3: forward and reverse current are internally limited. parameter conditions min typ max units supply voltage range 2.75 5.50 v v in_ = v cc = 5v, t a = +25? 60 v in_ = v cc = 3v, t a = +25? 80 switch on-resistance v in_ = v cc = 5v, t a = -40? to +85? 30 100 m ? in standby supply current v on_ = 0v 3 7.5 ? v ona = 5v, v onb = v onc = 0v 40 80 v ona = v on0b = 5v, v onc = 0v 55 100 in quiescent supply current i out_ = 0a v ona = v onb = v onc = 5v 60 120 ? out_ off-leakage current v on_ = 0v, v out_ = 0v 0.02 10 ? undervoltage-lockout threshold v in_ rising, 3% hysteresis 2.2 2.5 2.7 v continuous load current 1.2 a r seti = 26.1k ? 1.20 1.37 1.54 r seti = 39.2k ? 0.79 0.91 1.03 current-limit threshold r seti = 60.4k ? 0.49 0.59 0.68 a r seti = 26.1k ? 1.46 1.8 2.20 r seti = 39.2k ? 1.2 short-circuit current limit (peak amps) v out_ = 0v r seti = 60.4k ? 0.77 a r seti = 26.1k ? 0.55 r seti = 39.2k ? 0.37 short-circuit current limit (rms amps) v out_ = 0v r seti = 60.4k ? 0.23 a(rms) short-circuit/continuous current- limit transition output voltage threshold (note 5) 1 v
max1564 triple 1.2a usb switch in 4mm x 4mm thin qfn _______________________________________________________________________________________ 3 electrical characteristics (continued) (v in_ = v cc = v sel = v on_ = 5v, r seti = 26.1k ? , t a = -40? to +85?, unless otherwise noted. typical values are at t a = +25?.) (note 4) parameter conditions min typ max units current-limit fault-blanking timeout period from current-limit condition to flt_ low 10 20 40 ms turn-on delay r out _ = 10 ? , c out_ = 1?, measured from on_ high to 10% of v out_ 0.5 1.5 4.0 ms output rise time r out_ = 10 ? , c out _= 1?, measured from 10% to 90% of v out_ 3.5 ms turn-off delay time r out_ = 10 ? , c out_ = 1?, measured from on_ low to 90% of v out_ 100 1000 ? output fall time r out_ = 10 ? , c out_ = 1?, measured from 90% to 10% of v out_ 4.0 ms thermal shutdown threshold 10? hysteresis +160 ? v in_ = 2.7v to 4.0v 1.6 logic-input high voltage (ona, onb, onc, sel) v in_ = 4.0v to 5.5v 2.0 v v in_ = 2.7v to 4.0v 0.6 logic-input low voltage (ona, onb, onc, sel) v in_ = 4.0v to 5.5v 0.8 v logic-input current -1 +1 ? flt_ output low voltage i sink = 1ma 0.4 v flt_ output high leakage current v flt_ = 5.5v 1 a seti output voltage 600 mv seti external resistor range 26.1k ? sets 1.37a maximum current limit 26 60 k ? out_ auto-restart current in latched-off state, v out_ = 0v 10 25 50 ma out_ auto-restart threshold in latched-off state, v out_ rising 0.4 0.5 0.6 v out_ auto-restart delay time in latched-off state, v out_ > 1v 10 20 40 ms reverse current detection threshold 0.9 a reverse current detection blank time 10 20 40 ms note 4: specifications to -40? are guaranteed by design and characterization and not production tested. note 5: the output voltage at which the device transitions from short-circuit current limit to continuous current limit.
max1564 triple 1.2a usb switch in 4mm x 4mm thin qfn 4 ________________________________________________________________________________________ typical operating characteristics (circuit of figure 1, v ina = v inb = v inc = v sel = v ona = v onb = v onc = 5v, t a = +25?, unless otherwise noted.) current limit vs. r seti max1564 toc01 r seti (k ? ) current limit (a) 66 36 46 56 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 0 26 quiescent supply current vs. input voltage max1564 toc02 input voltage (v) input current ( a) 5 4 1 2 3 10 20 30 40 50 60 70 80 0 06 temperature ( c) 60 35 10 -15 30 40 50 60 70 80 20 -40 85 quiescent supply current vs. temperature max1564 toc03 input current ( a) v in = 5.5v v in = 4.5v v in = 5v standby current vs. temperature max1564 toc04 temperature ( c) input current ( a) 60 35 -15 10 0.5 1.0 1.5 2.0 3.0 2.5 3.5 4.0 0 -40 85 v ona = v onb = v onc = 0v switch off leakage current vs. temperature max1564 toc05 temperature ( c) leakage current ( a) 60 35 10 -15 0.01 0.1 1 10 0.001 -40 85 v ona = v onb = v onc = 0v v out = 0v reverse block leakage current vs. output voltage max1564 toc06 ouput voltage (v) leakage current ( a) 4.8 4.1 3.4 10 2.7 5.5 100 1 normalized on-resistance vs. temperature max1564 toc07 temperature ( c) normalized r on 60 35 10 -15 0.75 1.00 1.25 1.50 0.50 -40 85 continuous current limit vs. temperature max1564 toc08 temperature ( c) current limit (a) 60 35 10 -15 1.05 1.10 1.15 1.20 1.25 1.30 1.35 1.40 1.45 1.50 1.00 -40 85 output rise time vs. temperature output rise time (ms) 1 2 3 4 5 6 7 8 9 10 0 max1564 toc09 temperature ( c) 60 35 10 -15 -40 85 v in = 5.5v, r load = 5 ? v in = 5v, r load = 5 ? v in = 4.5v, r load = 5 ? v in = 5v, no load v in = 5.5v, no load v in = 4.5v, no load
max1564 triple 1.2a usb switch in 4mm x 4mm thin qfn _______________________________________________________________________________________ 5 typical operating characteristics (continued) (circuit of figure 1, v ina = v inb = v inc = v sel = v ona = v onb = v onc = 5v, t a = +25?, unless otherwise noted.) output fall time vs. temperature output fall time (ms) 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0 2.0 max1564 toc10 temperature ( c) 60 35 10 -15 -40 85 r load = 5 ? v in = 5v v in = 5.5v v in = 4.5v fault-blanking time (ms) 18 19 20 21 23 22 24 25 17 fault-blanking time vs. temperature max1564 toc11 temperature ( c) 60 35 10 -15 -40 85 v in = 5v v in = 5.5v v in = 4.5v auto-restart current vs. temperature max1564 toc13 auto-restart current (ma) 5 10 15 20 30 25 35 40 0 temperature ( c) 60 35 10 -15 -40 85 v in = 5v v in = 5.5v v in = 4.5v 4.8 4.1 3.4 2.7 5.5 auto-restart current vs. input voltage max1564 toc14 input voltage (v) auto-restart current (ma) 16 18 20 22 24 26 28 14 t a = +85 c t a = +25 c t a = -40 c flt_ low voltage vs. temperature v flt_ (mv) 125 175 225 275 75 max1564 toc12 temperature ( c) 60 35 10 -15 -40 85 r pullup = 5k ? v in = 5v v in = 5.5v v in = 4.5v
max1564 triple 1.2a usb switch in 4mm x 4mm thin qfn 6 _______________________________________________________________________________________ 4ms/div overload response into 2.5 ? max1564 toc15 v in (ac-coupled) v out_ 1a/div 2v/div 5v/div 100mv/div i out_ v flt_ 10ms/div short-circuit response into 0 ? max1564 toc16 v in (ac-coupled) v out_ 1a/div 5v/div 5v/div 200mv/div i out_ v flt_ 1ms/div switch turn-on time max1564 toc17 v out_ v on_ 1v/div 2v/div r load = 5 ? 1ms/div switch turn-off time max1564 toc18 v out_ v on_ 1v/div 2v/div r load = 5 ? typical operating characteristics (continued) (circuit of figure 1, v ina = v inb = v inc = v sel = v ona = v onb = v onc = 5v, t a = +25?, unless otherwise noted.)
max1564 triple 1.2a usb switch in 4mm x 4mm thin qfn _______________________________________________________________________________________ 7 detailed description undervoltage lockout (uvlo) and input voltage requirements the max1564 includes undervoltage-lockout (uvlo) circuitry to prevent erroneous switch operation when the input voltage is low during startup and brownout conditions. the ic is disabled when the input voltage is less than 2.5v (typ). flt_ asserts low during a uvlo condition. current-limit fault protection the max1564 uses two methods to protect the circuit from overcurrent conditions. during an overcurrent event, the ic senses the switch output voltage and selects either continuous current limiting or short-circuit pin description pin name function 1 ina input power supply for outa. provides power to outa. ina, inb, inc, and v cc must be connected together externally. bypass with a 0.1? capacitor to gnd. additional capacitors can be used as required. 2v cc input power supply for the max1564. provides power to the ic. ina, inb, inc, and v cc must be connected together externally. 3 inb input power supply for outb. provides power to outb. ina, inb, inc, and v cc must be connected together externally. 4inc input power supply for outc. provides power to outc. ina, inb, inc, and v cc must be connected together externally. 5 sel polarity control input. selects the polarity of ona, onb, and onc. connect to v cc for active-high on_ inputs. connect to gnd for active-low on_ inputs. 6 seti current-limit program input. connect a resistor from seti to gnd in the 26k ? to 60k ? range. i lim = 1.37a x 26.1k ? / r seti . 7 fltb fault-indicator output for switch b. fltb is an open-drain output that goes low when inb is below the uvlo threshold, or when switch b is in current limit for greater than 20ms, or when switch b is in thermal shutdown. 8 fltc fault indicator output for switch c. fltc is an open-drain output that goes low when inc is below the uvlo threshold, or when switch c is in current limit for greater than 20ms, or when switch c is in thermal shutdown. 9 outc power output for switch c. outc is high impedance during shutdown. 10 outb power output for switch b. outb is high impedance during shutdown. 11 gnd ground. connect ground to the exposed pad directly under the ic. 12 outa power output for switch a. outa is high impedance during shutdown. 13 flta fault indicator output for switch a. flta is an open-drain output that goes low when ina is below the uvlo threshold, or when switch a is in current limit for greater than 20ms, or when switch a is in thermal shutdown. 14 onc control input for switch c. onc is active high when sel is connected to v cc and active low when sel is connected to gnd. 15 onb control input for switch b. onb is active high when sel is connected to v cc and active low when sel is connected to gnd. 16 ona control input for switch a. ona is active high when sel is connected to v cc and active low when sel is connected to gnd. ep exposed pad. connect exposed pad to a large ground plane to improve thermal power dissipation.
max1564 triple 1.2a usb switch in 4mm x 4mm thin qfn 8 _______________________________________________________________________________________ current limiting. when v out_ is greater than 1v, the device operates in continuous current-limit mode and limits output current to a user-programmable level. when v out_ is less than 1v, the device operates in short-circuit current-limit mode and pulses the output current to levels that are 30% (typ) higher than the selected current limit. when either fault condition per- sists for 20ms (typ), the output turns off and its fault flag is asserted. the output automatically restarts 20ms after the short or overload is removed. auto-restart mode the max1564 detects short-circuit removal by sourcing 25ma from the output and monitoring the output volt- age. when the voltage at the output exceeds 0.5v for 20ms, the fault flag resets, the output turns back on, and the 25ma current source turns off. active loads are not expected to draw measurable current when sup- plied with less than 0.5v. the max1564 can also be reset from a fault by toggling the on_ input for the offending channel. reverse current blocking the usb specification does not allow an output device to source current back into the usb port. however, the max1564 is designed to safely power noncompliant devices. during normal operation with the channel enabled, the ic immediately turns off the switch if the output voltage rises above the input voltage sufficiently to create a reverse current in excess of 0.9a (typ). if the output voltage condition persists for longer than 20ms (typ), the switch remains off and the flt_ flag is assert- ed. when any channel is disabled, the output is switched to a high-impedance state, blocking reverse current flow from the output back to the input. thermal shutdown independent thermal shutdown of each channel per- mits delivering power to normal loads even if one load has a fault condition. the thermal limit does not have the 20ms fault blanking but sets the same fault latch that is used for other faults. exiting this latched state is described in the auto-restart mode section. fault indicators and fault blanking the max1564 provides an independent open-drain fault output ( flt_ ) for each switch. connect flt_ to in_ through a 100k ? pullup resistor for most applications. flt_ asserts low when any of the following conditions occur: the input voltage is below the uvlo threshold. the switch junction temperature exceeds the +160? thermal-shutdown temperature limit. the switch is in current-limit or short-circuit current- limit mode after the fault-blanking period (20ms typ) expires. the reverse current condition exists after the fault- blanking period expires. the flt_ output goes high impedance after a 20ms delay once the fault condition is removed. ensure that the max1564 input bypass capacitance prevents glitches from triggering the flt_ outputs. to differenti- ate large capacitive loads from short circuits or sus- tained overloads, the max1564 has an independent fault-blanking circuit for each switch. when a load tran- sient causes the output to enter current limit, an internal counter monitors the duration of the fault. for load faults exceeding the 20ms fault-blanking time, the switch turns off, flt_ asserts low, and the output enters auto-restart mode (see the current-limit fault protection and auto-restart mode sections). only cur- rent-limit and short-circuit faults are blanked. thermal- overload faults and input voltages below the uvlo threshold immediately turn off the offending output and assert flt_ low. fault blanking allows the max1564 to handle usb loads that might not be fully compliant with usb specifications. the max1564 successfully powers usb max1564 ina 1 3 4 2 5 16 15 14 6 11 9 10 12 8 7 13 inb inc v cc sel outa outb outc ona onb onc flta fltb fltc r2 100k ? r3 100k ? r1 26.1k ? r4 100k ? c2 1 f c1 0.1 f c3 1 f c4 1 f seti input 2.75v to 5.5v usb port a usb port b usb port c gnd active-high/ active-low select input figure 1. typical application circuit
max1564 triple 1.2a usb switch in 4mm x 4mm thin qfn _______________________________________________________________________________________ 9 loads with additional bypass capacitance and/or large startup currents while protecting the upstream power source. no fault is reported if the output voltage rises nominal within the 20ms blanking period. applications information setting the current limit the current limit for the max1564 is user programma- ble using the seti input. connect a resistor from seti to gnd (r1) to set the current limit. the value for r1 is calculated as: i limit = 1.37a x 26.1k ? / r1 r1 must be between 26k ? and 60k ? . input capacitor to limit the input voltage drop during momentary output load transients, connect a capacitor from in_ to ground. a 0.1? ceramic capacitor is required for local decoupling; however, higher capacitor values further reduce the voltage drop at the input. when driving inductive loads, a larger capacitance prevents voltage spikes from exceeding the max1564? absolute maxi- mum ratings. output capacitor a capacitor as large as 2000? may be used on the output to smooth out transients and/or increase rise/fall times. larger output capacitance may be used, but the resulting output charge time during startup may exceed the fault blanking period, resulting in a flt_ flag. driving inductive loads a wide variety of devices (mice, keyboards, cameras, and printers) typically connect to the usb port with cables, adding an inductive component to the load. this inductance causes the output voltage at the usb port to oscillate during a load step. the max1564 drives induc- tive loads; however, care must be taken to avoid exceeding the device? absolute maximum ratings. usually, the load inductance is relatively small, and the max1564? input includes a substantial bulk capaci- tance from an upstream regulator, as well as local bypass capacitors, limiting overshoot. if severe ringing occurs because of large load inductance, clamp the max1564 outputs below +6v and above -0.3v. turn-on and turn-off behavior slow turn-on and turn-off under normal operating condi- tions minimizes loading transients on the upstream power source. rapid turn-off under fault conditions (thermal, short circuit, and uvlo) is done for maximum safety. sel sets the active polarity of the logic inputs of the max1564. connect on_ to the same voltage as sel to enable the respective out_ switch. connect on_ to the opposite voltage as sel to disable the respective output (see table 1). the output of a disabled switch enters a high-impedance state. layout and thermal dissipation keep all input/output traces as short as possible to reduce the effect of undesirable parasitic inductance and optimize the switch response time to output short- circuit conditions. place input and output capacitors no more than 5mm from device leads. connect in_ and out_ to the power bus with short traces. wide power bus planes at in_ and out_ provide superior heat dissi- pation as well. an active switch dissipates little power with minimal change in package temperature. calculate the power dissipation for this condition as follows: p = i out_ 2 x r on at the normal operating current (i out_ = 0.5a) and the maximum on-resistance of the switch (100m ? ), the power dissipation is: p = (0.5a) 2 x 0.100 ? = 25mw per switch the worst-case power dissipation occurs when the out- put current is just below the current-limit threshold with an output voltage greater than 1v. in this case, the power dissipated in each switch is the voltage drop across the switch multiplied by the current limit: p = i lim x (v in - v out ) for a 5.5v input and 1v output, the maximum power dissipation per switch is: p = 1.54a x (5.5v - 1v) = 6.9w because the package power dissipation is 1349mw, the max1564 die temperature may exceed the +160? thermal-shutdown threshold, in which case the switch output shuts down until the junction temperature cools by 10?. in a continuous overload condition, this caus- es a cyclical on/off situation. the duty cycle and period of this situation are strong functions of the ambient tem- perature and the pc board layout (see the thermal shutdown section). sel on_ out_ state high high enabled high low disabled low high disabled low low enabled table 1. sel/on_ inputs
max1564 triple 1.2a usb switch in 4mm x 4mm thin qfn 10 ______________________________________________________________________________________ if the output current exceeds the current-limit threshold, or the output voltage is pulled below the short-circuit detect threshold, the max1564 enters a fault state after 20ms, at which point auto-restart mode is enabled and 25ma is sourced by the output. for a 5v input, out_ short circuited to gnd, and auto-restart mode active, the power dissipation is as follows: p = 0.025a x 5v = 0.125w chip information transistor count: 4793 process: bicmos
max1564 triple 1.2a usb switch in 4mm x 4mm thin qfn 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 ____________________ 11 2004 maxim integrated products printed usa is a registered trademark of maxim integrated products. 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 .) 24l qfn thin.eps c 1 2 21-0139 package outline 12, 16, 20, 24l thin qfn, 4x4x0.8mm c 2 2 21-0139 package outline 12, 16, 20, 24l thin qfn, 4x4x0.8mm

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