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information furnished by analog devices is believed to be accurate and reliable. however, no responsibility is assumed by analog devices for its use, nor for any infringements of patents or other rights of third parties which may result from its use. no license is granted by implication or otherwise under any patent or patent rights of analog devices. ADM1072 one technology way, p.o. box 9106, norwood, ma 02062-9106, u.s.a. tel: 781/329-4700 world wide web site: http://www.analog.com fax: 781/326-8703 ? analog devices, inc., 2002 rev. pre 1/02 preliminary technical data dual, usb 2.0 full/standby power controller with supply steering functional block diagram features 500ma load current (100ma in standby mode) 135m on resistance switchable current limit 50a typical quiescent current 10na typical shutdown current 40na typical switch off leakage short-circuit protection thermal shutdown outputs small, 16-pin qsop package applications desktop computers palmtop computers notebook computers hand-held instruments universal serial bus (usb ) general description the ADM1072 is a logic controlled, dual p-channel switch with low on resistance and a built-in current limiter, capable of sourcing up to 1a from supply voltages between 2.7v and 5.5v. in addition to logic inputs that switch each channel on and off, the device has a standby input that switches the output current limit, making it ideal for use with usb peripherals. in normal operating mode and standby mode the output current is typically limited to 500ma and 100ma respectively, as outlined by the usb2.0 specification. this allows the system power supply to be protected against short-circuits and surge currents in peripheral usb devices powered via the ADM1072. over-current and over-temperature conditions are signalled by a fault output for each channel. the ADM1072 also offers low quiescent current of typically 50a and shutdown current of typically 10na. 4 120f 5 0.2a main fet 0.2a mirror fet mirror amplifier main_in (2.7v to 5.5v) 4.7f 3 temperature sensor 7 14 current limit amplifier on1 1.24v bandgap reference overtemp ADM1072 10 current setting resistor r pullup 10k to 100k v pullup 0 to 5.5v flt2 8 15 11 gnd channel 2 is identical to channel 1 to channel 2 13 op2 120f r pullup 10k to 100k v pullup 0 to 5.5v flt1 6 stby on2 undervoltage sensor to channel 2 to channel 2 to channel 2 9 2 1a mirror fet 1a main fet 12 stby_in (2.7v to 5.5v) 22f op1 16 control logic 1
?2? rev. pre 1/02 ADM1072?pecifications parameter min typ max units test conditions/comments operating voltage range +2.7 +5.5 volts quiescent current (total device) 50 a v in = 5v,
= gnd, i out = 0a shutdown supply current (total device) 0.01 2 a
= v in = 5.5v, v out = 0v undervoltage lockout 2.0 2.3 2.6 v v stby_in , rising edge, 1% hysteresis on resistance ? 135 m v in = 4.75v ?? m v in = 3.0v nominal current-limit full power mode 0.8 1.0 1.2 a stby low note 1 standby mode 160 200 240 ma stby high note 1
stby input low voltage, v il 0.8 v v in = 2.7v to 5.5v
stby input high voltage, v ih 2.4 v v in = 2.7v to 5.5v
stby input leakage 0.01 1 a v v stby = 5.5v
logic output low voltage 0.4 v i sink = 1ma
output high leakage current 0.05 1 a v fault = 5.5v turn-on time 4 ms v in = 5v, i out = 500ma 4msv in = 3v, i out = 500ma turn-off time ? ? 20 s v in = 5v, i out = 500ma notes 1 current limit is specified with v out = 4.5v. 2 guaranteed by design. derived from the i set current ratio, current-limit amplifier and internal set resistor accuraciues. 3 tested with i out = 200ma and v set adjusted until (v in - v out ) 0.8v. 4 specifications to -40 o c are guaranteed by design, not tested. (specification for either channel 1 or channel 2, v in = +5.0v, t a = -40 to +85 o c, unless otherwise noted.)
ADM1072 ?3? rev. pre 1/02 pin configuration absolute maximum ratings* (t a = +25c unless otherwise noted) main_in to gnd . . . . . . . . . . . . . . . . . . . . . . ?0.3v to +6v ,
to gnd . . . . . . . . . . . ?0.3v to +6v
to gnd . . . . . . . . . . . . . . . . +0.3 v to (v in + 0.3v) maximum switch current full power mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1a standby power mode . . . . . . . . . . . . . . . . . . . . . . . . 200ma continuous power dissipation (ta = +70 o c) . . . . . 667mw qsop (derate 8.3mw/ o c above +70 o c) operating temperature range industrial (a version) . . . . . . . . . . . . . . . ?40c to +85c storage temperature range . . . . . . . . . . . ?65c to +150c lead temperature (soldering, 10 sec) . . . . . . . . . . . +300c *this is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operation sections of this speci- fication is not implied. exposure to absolute maximum rating conditions for extended periods of time may affect reliability. pin function description pin mnemonic function 2, 3, 14, 15 main_in input to main p-channel mosfet source (both channels). bypass main_in with a 22f capacitor to ground. 5, 12 stby_in input to standby p-channel mosfet source (both channels) and supply to chip circuitry. bypass stby_in with a 4.7f capacitor to ground. 1, 4 op1 output from channel 1, p-channel mosfet drains. bypass op1 with a 120f capacitor to ground. 13, 16 op2 output from channel 2, p-channel mosfet drains. bypass op2 with a 120f capacitor to ground. 6 open-drain digital output. goes low when the channel 1 current limit is exceeded for 10ms or the die temperature exceeds +150 o c. during startup, remains low for the turn-on time. 7
open-drain digital output.
goes low when the channel 2 current limit is exceeded for 10ms or the die temperature exceeds +150 o c. during startup,
remains low for the turn-on time. 8 gnd ground pin for all chip circuits. 9 stby digital input. active high standby mode input. stby = 0 sets normal operating mode with 500ma current limit. stby = 1 sets standby mode with 100ma current limit. 10
digital input. active-low switch enable for channel 2 (logic 0 turns the switch on). 11 digital input. active-low switch enable for channel 1 (logic 0 turns the switch on). thermal characteristics 16-pin qsop package: q ja = 105c/watt, q jc = 40c/watt ordering guide temperature package package model range description option ADM1072arq -40c to +85c 16-pin qsop rq-16 package ADM1072 top view (not to scale) 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 op1 main_in main_in op1 stby_in gnd op2 main_in main_in op2 stby_in stby
ADM1072 ?4? rev. pre 1/02 typical performance curves aw ai t i ng da ta figure 1. quiescent current vs. input voltage aw ai t i ng da ta figure 2. quiescent current vs. temperature aw ai t i ng da ta figure 3. off-supply current vs. temperature aw ai t i ng da ta figure 4. off-switch current vs. temperature aw ai t i ng da ta figure 5. normalized on resistance vs. temperature aw ai t i ng da ta figure 6. i out /i set ratio vs switch current
ADM1072 ?5? rev. pre 1/02 aw ai t i ng da ta figure 7. normalized output current vs. output voltage aw ai t i ng da ta figure 8. turn-on time vs. temperature aw ai t i ng da ta figure 9. turn-off time vs. temperature aw ai t i ng da ta figure 10. fast current-limit response aw ai t i ng da ta figure 11. slow current-limit response aw ai t i ng da ta figure 12. load transient response typical performance curves
ADM1072 ?6? rev. pre 1/02 aw ai t i ng da ta figure 13. switch turn-on time aw ai t i ng da ta figure 14. switch turn-off time aw ai t i ng da ta figure 15. usb circuit output rise time aw ai t i ng da ta figure 16 usb circuit output fall time typical performance curves
ADM1072 ?7? rev. pre 1/02 functional description the ADM1072 is a dual, logic-controlled p-channel switch. each channel of the ADM1072 comprises two p-channel switches. the source of one switch is connected to the ?main_in? input pins and can switch up to 1a. the second switch is conected to the ?stby_in? pins and can switch up to 200ma. the device is rated to provide 500ma continuously in full power mode and 100ma continuously in stby mode. the stby_in inputs also provide the power for the chip circuitry and so must be connected to a supply at all times. when stby is low the main switch is active and when stby is high the standby switch is active. each channel is individually controlled by an active-low logic input (pin 11) and
(pin 10). when either or
is low, the internal circuitry of the ADM1072 is powered up and the output of the corresponding current-limit amplifier is low, providing gate drive to the switching fet, thus turning it on. when both inputs are high, the internal circuitry is powered down and the current consumption is typically 10na. it should be noted that the ADM1072 is not a bi-directional switch, so v in must always be higher than v out . table 1. truth table for , and stby stby channel 1 channel 2 0 0 0 500ma 500ma 0 0 1 100ma 100ma 0 1 0 500ma off 0 1 1 100ma off 1 0 0 off 500ma 1 0 1 off 100ma 1 1 x both shut down x = don?t care current limit when either the main or standby switch is turned on a smaller mirror switch passes a proportionate current equal to i out / 1000. the mirror amplifier maintains this relationship by keeping the drain of the mirror fet at the same voltage as the main fet, and drives the mirror current through an internal current-limit resistor, which is connected between the non- inverting input of the current limit amplifier and ground. an on-chip bandgap reference of 1.24v is connected to the inverting input of the current-limit amplifier. when the load current exceeds the preset limit, the voltage across the current- limit resistor exceeds 1.24v and the output voltage of the cur- rent-limit amplifier rises, reducing the gate drive to the fets. by selecting between the standby and main fets and their associated mirror fets, the stby input allows the two differ- ent values of current limit specified by usb2.0 to be selected. this feature is particularly useful when driving usb peripherals from a host system such as a pc that can go into a power- saving mode, since it limits the current that the peripherals can attempt to draw from the host power supply. short-circuit protection the proportional relationship between the main fet and the mirror fet is only maintained down to an output voltage of about 1.6v. below this voltage the output current is limited to approximately 1.2 x i limit . in the event of a high dv/dt across the switching fet during a short-circuit, the switch will turn off and disconnect the input from the output. the switch is then turned on slowly with the current limited to the short-circuit value. thermal shutdown the thermal shutdown operates when the die temperature exceeds +150 o c, turning off both channels. the thermal shut- down circuit has built-in hysteresis of 10 o c, so the switch will not turn on again until the die temperature falls to +140 o c. if the fault condition is not removed, the switch will pulse on and off as the temperature cycles between these limits. undervoltage lockout the undervoltage sensor monitors the input supply voltage (ie) the voltage on stby_in. the outputs will not turn on until the supply voltage is sufficient for the chip circuits to operate reliably. undervoltage lockout occurs at between 2.0 and 2.6v. outputs the ADM1072 has active-low fault outputs for each channel, (pin 6) and
(pin 7). if the current limit is exceeded for greater than 10ms, the corresponding output will pull low. if the thermal shutdown is activated, both outputs will pull low. the outputs are open-drain and require a pullup resistor of between 10k and 100k . several outputs may be wire- or?d to form a common interrupt line, as shown in figure 17 or outputs may be wire-or?d to an existing interrupt line that has a resistive pullup. ADM1072 flt1 flt2 r pullup v pullup int ADM1072 flt1 flt2 ADM1072 flt1 flt2 figure 17. wire or?ing fault outputs during startup, the flt output goes low for the turn-on time.
ADM1072 ?8? rev. pre 1/02 outline dimensions dimensions shown in inches and (mm). 16-pin qsop package (rq-16) 16 9 8 1 0.197 (5.00) 0.189 (4.80) 0.244 (6.20) 0.228 (5.79) pin 1 0.157 (3.99) 0.150 (3.81) seating plane 0.010 (0.25) 0.004 (0.10) 0.012 (0.30) 0.008 (0.20) 0.025 (0.64) bsc 0.059 (1.50) max 0.069 (1.75) 0.053 (1.35) 0.010 (0.20) 0.007 (0.18) 0.050 (1.27) 0.016 (0.41) 8 0 applications information input filtering to prevent the input voltage being pulled below the minimum operating voltage under transient short-circuit conditions, before the current limit has had time to operate, a reservoir capacitor should be connected from main_in to gnd. this does not need to be large, but should have a low esr. a value of around 10 - 22f is suitable. larger values will reduce the voltage drop still further. the stby_in input requires a proportionately smaller value, typically 2.2 to 4.7f. output capacitance 120f capacitors should be connected between op1 and op2 and gnd to prevent the back e.m.f. of parasitic inductance from pulling op1 and op2 below ground during turn-off and to provide adequate turn- on current for universal serial bus (usb) applications that are hot plugged to op! or op2. this causes the output rise and fall times to be longer, as shown in the typical operating characteristics, but does not affect the turn-off time of the ADM1072 itself. layout considerations printed circuit board tracks to and from the ADM1072 should be as thick and as short as possible to minimise parasitic induc- tance and take full advantage of the fast response time of the switch. input and output capacitors should be placed as close to the device as possible (less than 5mm). thermal considerations under normal operating conditions, the worst-case power dissipation will be 135mw with the 135m on resistance and 3v supply (w = (1a) 2 0.135 ). the package is capable of handling and dissipating this power, but heat dissipation can further be improved by providing a large area of copper in contact with the device pins, particularly main_in and op1,op2.

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