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march 2000 1 mic2025/2075 mic2025/2075 micrel mic2025/2075 single-channel power distribution switch final information general description the mic2025 and mic2075 are high-side mosfet switches optimized for general-purpose power distribution requiring circuit protection. the mic2025/75 are internally current limited and have thermal shutdown that protects the device and load. the mic2075 offers ?mart?thermal shutdown that reduces cur- rent consumption in fault modes. when a thermal shutdown fault occurs, the output is latched off until the faulty load is removed. removing the load or toggling the enable input will reset the device output. both devices employ soft-start circuitry that minimizes inrush current in applications where highly capacitive loads are employed. a fault status output flag is provided that is asserted during overcurrent and thermal shutdown condi- tions. the mic2025/75 is available in the mm8 8-lead msop and 8-lead sop. typical application en out flg in on/off overcurrent mic2025/75 logic controller gnd out nc v cc 2.7v to 5.5v 0.1f 10k 1f vin gnd nc load features 140m ? maximum on-resistance 2.7v to 5.5v operating range 500ma minimum continuous output current short-circuit protection with thermal shutdown fault status flag with 3ms filter eliminates false asser- tions undervoltage lockout reverse current flow blocking (no body diode ) circuit breaker mode (mic2075) reduces power consumption logic-compatible input soft-start circuit low quiescent current pin-compatible with mic2525 applications usb peripherals general purpose power switching acpi power distribution notebook pcs pdas pc card hot swap micrel, inc. ?1849 fortune drive ?san jose, ca 95131 ?usa ?tel + 1 (408) 944-0800 ?fax + 1 (408) 944-0970 ?http://www.mic rel.com mm8 is a trademark of micrel, inc.
mic2025/2075 micrel mic2025/2075 2 march 2000 pin description pin number pin name pin function 1 en switch enable (input): active-high (-1) or active-low (-2). 2 flg fault flag (output): active-low, open-drain output. indicates overcurrent or thermal shutdown conditions. overcurrent condition must exceed t d in order to assert flg. 3 gnd ground 4 nc not internally connected 5 nc not internally connected 6, 8 out supply (output): pins must be connected together. 7 in supply voltage (input). ordering information part number enable temperature range package mic2025-1bm active high 40 c to +85 c 8-lead sop mic2025-2bm active low 40 c to +85 c 8-lead sop mic2025-1bmm active high 40 c to +85 c 8-lead msop mic2025-2bmm active low 40 c to +85 c 8-lead msop mic2075-1bm active high 40 c to +85 c 8-lead sop mic2075-2bm active low 40 c to +85 c 8-lead sop mic2075-1bmm active high 40 c to +85 c 8-lead msop mic2075-2bmm active low 40 c to +85 c 8-lead msop pin configuration 1 2 3 4 8 7 6 5 out in out nc en flg gnd nc mic2025/75 8-lead sop (bm) 8-lead msop (bmm)
march 2000 3 mic2025/2075 mic2025/2075 micrel electrical characteristics v in = +5v; t a = 25 c, bold values indicate 40 c t a +85 c; unless noted symbol parameter condition min typ max units i dd supply current mic20x5-1, v en 0.8v, (switch off), 0.75 5 a out = open mic20x5-2, v en 2.4v, (switch off), 0.75 5 a out = open mic20x5-1, v en 2.4v, (switch on), 160 a out = open mic20x5-2, v en 0.8v, (switch on), 160 a out = open v en enable input voltage low-to-high transition 2.1 2.4 v high-to-low transition 0.8 1.9 v enable input hysteresis 200 mv i en enable input current v en = 0v to 5.5v 1 0.01 1 a control input capacitance 1 pf r ds(on) switch resistance v in = 5v, i out = 500ma 90 140 m ? v in = 3.3v, i out = 500ma 100 160 m ? output leakage current mic2025/2075 (output off) 10 a off current in latched mic2075 50 a thermal shutdown (during thermal shutdown state) t on output turn-on delay r l = 10 ? , c l = 1 f, see timing diagrams 1 2.5 6 ms t r output turn-on rise time r l = 10 ? , c l = 1 f, see timing diagrams 0.5 2.3 5.9 ms t off output turnoff delay r l = 10 ? , c l = 1 f, see timing diagrams 50 100 s t f output turnoff fall time r l = 10 ? , c l = 1 f, see timing diagrams 50 100 s i limit short-circuit output current v out = 0v, enabled into short-circuit. 0.5 0.7 1.25 a current-limit threshold ramped load applied to output, note 4 0.85 1.25 a short-circuit response time v out = 0v to i out = i limit 24 s (short applied to output) t d overcurrent flag response v in = 5v, apply v out = 0v until flg low 1.5 3 7 ms delay v in = 3.3v, apply v out = 0v until flg low 1.5 3 8 ms undervoltage lockout v in rising 2.2 2.5 2.7 v threshold v in falling 2.0 2.3 2.5 v absolute maximum ratings (note 1) supply voltage (v in ) ........................................ 0.3v to 6v fault flag voltage (v flg ) .............................................. +6v fault flag current (i flg ) ............................................ 25ma output voltage (v out ) .................................................. +6v output current (i out ) ............................... internally limited enable input (i en ) ..................................... 0.3v to v in +3v storage temperature (t s ) ....................... 65 c to +150 c esd rating, note 3 operating ratings (note 2) supply voltage (v in ) ................................... +2.7v to +5.5v ambient temperature (t a ) ......................... 40 c to +85 c junction temperature (t j ) ....................... internally limited thermal resistance sop ( ja ) .......................................................... 160 c/w msop( ja ) ........................................................ 206 c/w
mic2025/2075 micrel mic2025/2075 4 march 2000 test circuit device under test c l out r l v out i out timing diagrams 90% v out 10% 90% 10% t r t f output rise and fall times v en 50% 90% v out 10% t off t on active-low switch delay times (mic20x5-2) v en 50% 90% v out 10% t off t on active-high switch delay times (mic20x5-1) symbol parameter condition min typ max units error flag output i l = 10ma, v in = 5v 8 25 ? resistance i l = 10ma, v in = 3.3v 11 40 ? error flag off current v flag = 5v 10 a overtemperature threshold t j increasing 140 c t j decreasing 120 c note 1. exceeding the absolute maximum rating may damage the device. note 2. the device is not guaranteed to function outside its operating rating. note 3. devices are esd sensitive. handling precautions recommended. note 4. see functional characteristics: current-limit response graph.
march 2000 5 mic2025/2075 mic2025/2075 micrel 0 20 40 60 80 100 120 140 160 180 -40 -20 0 20 40 60 80 100 current ( a) temperature ( c) supply on-current vs. temperature 5v 3.3v 0 20 40 60 80 100 120 140 160 -40 -20 0 20 40 60 80 100 on-resistance (m ? ) temperature ( c) on-resistance vs. temperature 5v 3.3v i out = 500ma 0 50 100 150 200 2.5 3.0 3.5 4.0 4.5 5.0 5.5 resistance (m ? ) input voltage (v) on-resistance vs. input voltage i out = 500ma +85 c +25 c -40 c 0 1 2 3 4 5 -40 -20 0 20 40 60 80 100 rise time (ms) temperature ( c) turn-on rise time vs. temperature r l =10 ? c l =1 f v in = 5v v in = 3.3v 0 50 100 150 200 2.5 3.0 3.5 4.0 4.5 5.0 5.5 current ( a) input voltage (v) supply on-current vs. input voltage +85 c +25 c -40 c 0 200 400 600 800 1000 1200 -40 -20 0 20 40 60 80 100 current limit threshold (ma) temperature ( c) current-limit threshold vs. temperature v in = 3.3v v in = 5v 0 200 400 600 800 1000 -40 -20 0 20 40 60 80 100 current limit (ma) temperature ( c) short-circuit current-limit vs. temperature v in = 3.3v v in = 5v 0 1.0 2.0 3.0 4.0 5.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 rise time (ms) input voltage (v) turn-on rise time vs. input voltage r l =10 ? c l =1 f +85 c +25 c -40 c 0 100 200 300 400 500 600 700 800 2.5 3.0 3.5 4.0 4.5 5.0 5.5 current limit (ma) input voltage (v) short-circuit current-limit vs. input voltage +85 c +25 c -40 c 0 100 200 300 400 500 600 700 800 900 1000 1100 1200 2.5 3.0 3.5 4.0 4.5 5.0 5.5 current limit threshold (ma) input voltage (v) current-limit threshold vs. input voltage +85 c +25 c -40 c 0 0.5 1.0 1.5 2.0 2.5 2.5 3.0 3.5 4.0 4.5 5.0 5.5 enable threshold (v) input voltage (v) enable threshold vs. input voltage t a = 25 c v en falling v en rising 0 0.5 1.0 1.5 2.0 2.5 -40 -20 0 20 40 60 80 100 enable threshold (v) temperature ( c) enable threshold vs. temperature v in = 5v v en rising v en falling
mic2025/2075 micrel mic2025/2075 6 march 2000 0 1 2 3 4 5 -40 -20 0 20 40 60 80 100 delay time (ms) temperature ( c) flag delay vs. temperature v in = 3.3v v in = 5v 0 1 2 3 4 5 2.5 3.0 3.5 4.0 4.5 5.0 5.5 delay time (ms) input voltage (v) flag delay vs. input voltage +85 c +25 c -40 c 0 0.5 1.0 1.5 2.0 2.5 3.0 -40 -20 0 20 40 60 80 100 uvlo threshold (v) temperature ( c) uvlo threshold vs. temperature v in rising v in falling
march 2000 7 mic2025/2075 mic2025/2075 micrel functional characteristics uvlo v in rising (mic2025-1) time (10ms/div.) i out (100ma/div.) v in (1v/div.) v out (2v/div.) v flg (1v/div.) v en = v in v in = 5v c l = 57 f r l = 35 ? 2.5v uvlo v in falling (mic2025-1) time (25ms/div.) i out (100ma/div.) v in (2v/div.) v out (2v/div.) v flg (2v/div.) v en = v in v in = 5v c l = 57 f r l = 35 ? 2.3v turn-on response (mic2025-1) time (1ms/div.) i out (200ma/div.) v en (10v/div.) v out (5v/div.) v flg (5v/div.) v in = 5v c l = 147 f r l = 35 ? 640ma 144ma inrush current response (mic2025-1) time (1ms/div.) i out (200ma/div.) v en (10v/div.) v flg (5v/div.) v in = 5v r l = 35 ? c l = 310 f c l = 210 f c l = 110 f c l = 10 f enable into short (mic2025-1) time (1ms/div.) i out (500ma/div.) v en (10v/div.) v out (2v/div.) v flg (5v/div.) v in = 5v 3.1ms (t d ) 640ma short-circuit current turnoff response (mic2025-1) time (2.5ms/div.) i out (200ma/div.) v en (10v/div.) v out (5v/div.) v flg (5v/div.) v in = 5v c l = 147 f r l = 35 ? 144ma
mic2025/2075 micrel mic2025/2075 8 march 2000 current-limit response (ramped load into short mic2025-1) time (100ms/div.) i out (500ma/div.) v in (10v/div.) v out (5v/div.) v flg (5v/div.) v in = 5v c l = 47 f current-limit threshold (780ma) thermal shutdown short-circuit current (650ma) short removed current-limit transient response (enable into short mic2025-1) time (500 s/div.) i out (5a/div.) v out (5v/div.) v flg (5v/div.) v in = 5v c l = 47 f 640ma short-circuit current load no load current-limit transient response (mic2025-1) time (10 s/div.) i out (5a/div.) v out (5v/div.) v in = 5v c l = 47 f 640ma short-circuit current 24 s load no load thermal shutdown response (output reset by removing load mic2075-1) time (100ms/div.) i out (500ma/div.) v en (10v/div.) v out (5v/div.) v flg (5v/div.) thermal shutdown output is reset (load removed) ramped load to a short output latched off v in = 5v thermal shutdown (output reset by toggling enable mic2075-1) time (100ms/div.) i out (500ma/div.) v en (10v/div.) v out (5v/div.) v flg (5v/div.) thermal shutdown enable reset output reset r l = 35 ? ramped load to a short r l = 35 ? v in = 5v
march 2000 9 mic2025/2075 mic2025/2075 micrel block diagram 1.2v reference thermal shutdown osc. charge pump out uvlo gate control in flg en current limit gnd flag response delay functional description input and output in is the power supply connection to the logic circuitry and the drain of the output mosfet. out is the source of the output mosfet. in a typical circuit, current flows from in to out toward the load. if v out is greater than v in , current will flow from out to in since the switch is bidirectional when en- abled. the output mosfet and driver circuitry are also designed to allow the mosfet source to be externally forced to a higher voltage than the drain (v out > v in ) when the switch is disabled. in this situation, the mic2025/75 avoids undesirable current flow from out to in. thermal shutdown thermal shutdown is employed to protect the device from damage should the die temperature exceed safe margins due mainly to short circuit faults. each channel employs its own thermal sensor. thermal shutdown shuts off the output mosfet and asserts the flg output if the die temperature reaches 140 c. the mic2025 will automatically reset its output should the die temperature cool down to 120 c. the mic2025 output and flg signal will continue to cycle on and off until the device is disabled or the fault is removed. figure 2 depicts typical timing. if the mic2075 goes into thermal shutdown, its output will latch off and a pull-up current source is activated. this allows the output latch to automatically reset when the load (such as a usb device) is removed. the output can also be reset by toggling en. refer to figure 1 for details. depending on pcb layout, package, ambient temperature, etc., it may take several hundred milliseconds from the incidence of the fault to the output mosfet being shut off. the worst-case scenario of thermal shutdown is that of a short-circuit fault and is shown in the in the function char- acteristics: thermal shutdown response graph. power dissipation the device s junction temperature depends on several fac- tors such as the load, pcb layout, ambient temperature and package type. equations that can be used to calculate power dissipation of each channel and junction temperature are found below. p d = r ds(on) i out 2 total power dissipation of the device will be the summation of p d for both channels. to relate this to junction temperature, the following equation can be used: t j = p d ja + t a where: t j = junction temperature t a = ambient temperature ja = is the thermal resistance of the package current sensing and limiting the current-limit threshold is preset internally. the preset level prevents damage to the device and external load but still allows a minimum current of 500ma to be delivered to the load. the current-limit circuit senses a portion of the output mos- fet switch current. the current-sense resistor shown in the block diagram is virtual and has no voltage drop. the reaction to an overcurrent condition varies with three scenarios: switch enabled into short-circuit if a switch is enabled into a heavy load or short-circuit, the switch immediately enters into a constant-current mode, reducing the output voltage. the flg signal is asserted indicating an overcurrent condition. see the short-circuit response graph under functional characteristics.
mic2025/2075 micrel mic2025/2075 10 march 2000 short-circuit applied to enabled output when a heavy load or short-circuit is applied, a large transient current may flow until the current-limit circuitry responds. once this occurs the device limits current to less than the short-circuit current limit specification. see the short-circuit transient response graph under functional characteristics. current-limit response ramped load the mic2025/75 current-limit profile exhibits a small foldback effect of about 200ma. once this current-limit threshold is exceeded the device switches into a constant current mode. it is important to note that the device will supply current until the current-limit threshold is exceeded. see the current-limit response graph under functional characteristics. fault flag the flg signal is an n-channel open-drain mosfet output. flg is asserted (active-low) when either an overcurrent or thermal shutdown condition occurs. in the case where an overcurrent condition occurs, flg will be asserted only after the flag response delay time, t d , has elapsed. this ensures that flg is asserted only upon valid overcurrent conditions and that erroneous error reporting is eliminated. for ex- ample, false overcurrent conditions can occur during hot-plug events when a highly capacitive load is connected and causes a high transient inrush current that exceeds the current-limit threshold. the flg response delay time t d is typically 3ms. undervoltage lockout undervoltage lockout (uvlo) prevents the output mosfet from turning on until v in exceeds approximately 2.5v. under- voltage detection functions only when the switch is enabled. v en v out i out short-circuit fault thermal shutdown reached load removed (output reset) v flg i limit i dc t d figure 1. mic2075-2 timing: output reset by removing load v en v out i out short-circuit fault thermal shutdown reached load/fault removed v flg i dc i limit t d figure 2. mic2025-2 timing
march 2000 11 mic2025/2075 mic2025/2075 micrel applications information supply filtering a 0.1 f to 1 f bypass capacitor positioned close to v in and gnd of the device is strongly recommended to control supply transients. without a bypass capacitor, an output short may cause sufficient ringing on the input (from supply lead induc- tance) to damage internal control circuitry. printed circuit board hot-plug the mic2025/75 are ideal inrush current-limiters suitable for hot-plug applications. due to the integrated charge pump, the mic2025/75 presents a high impedance when off and slowly becomes a low impedance as it turns on. this soft- start feature effectively isolates power supplies from highly capacitive loads by reducing inrush current during hot-plug events. figure 3 shows how the mic2075 may be used in a hot-plug application. in cases of extremely large capacitive loads (>400 f), the length of the transient due to inrush current may exceed the delay provided by the integrated filter. since this inrush current exceeds the current-limit delay specification, flg will be asserted during this time. to prevent the logic controller from responding to flg being asserted, an external rc filter, as shown in figure 4, can be used to filter out transient flg assertion. the value of the rc time constant will be selected to match the length of the transient. universal serial bus (usb) power distribution the mic2025/75 is ideally suited for usb (universal serial bus) power distribution applications. the usb specification defines power distribution for usb host systems such as pcs and usb hubs. hubs can either be self-powered or bus- powered (that is, powered from the bus). figure 5 below shows a typical usb host application that may be suited for mobile pc applications employing usb. the requirements for usb host systems is that the port must supply a minimum of 500ma at an output voltage of 5v 5%. in addition, the output power delivered must be limited to below 25va. upon an overcurrent condition, the host must also be notified. to support hot-plug events, the hub must have a minimum of 120 f of bulk capacitance, preferably low-esr electrolytic or tantulum. refer to application note 17 for more details on designing compliant usb hub and host systems. for bus-powered hubs, usb requires that each downstream port be switched on or off under control by the host. up to four downstream ports each capable of supplying 100ma at 4.4v minimum are allowed. in addition, to reduce voltage droop on the upstream v bus , soft-start is necessary. although the hub can consume up to 500ma from the upstream bus the hub must consume only 100ma max at start-up, until it enumer- ates with the host prior to requesting more power. the same requirements apply for bus-powered peripherals that have no downstream ports. figure 6 shows a bus-powered hub. mic2025-2 en out flg gnd out nc in 18 27 36 5 nc 4 adaptor card to "hot" receptacle c bulk gnd v cc 0.1 f backend function figure 3. hot plug application 10k v+ mic2025 en out flg gnd out nc nc in 18 27 36 45 overcurrent logic controller r c figure 4. transient filter
mic2025/2075 micrel mic2025/2075 12 march 2000 v bus d+ d gnd usb port data en out flg in on/off overcurrent mic2025/75 3.3v usb controller gnd out nc v cc 5.0v 0.1f 10k in out gnd 4.50v to 5.25v upstream v bus 100ma max. ferrite beads 120f v bus d+ d gnd data 1f 1f vin gnd 3.3v nc mic5203-3.3 0.01f figure 5 usb host application v bus d+ d gnd usb downstream connector (up to four ganaged ports) data en out flg in on/off overcurrent mic2025/75 usb logic controller gnd out nc 0.1f 1.5k in out gnd usb upstream connector ferrite beads 120f v bus d+ d gnd data 0.1f 0.1f vin gnd 3.3v nc mic5203-3.3 (ldo) 0.01f 1.5k figure 6. usb bus-powered hub
march 2000 13 mic2025/2075 mic2025/2075 micrel package information 45 0 8 0.244 (6.20) 0.228 (5.79) 0.197 (5.0) 0.189 (4.8) seating plane 0.026 (0.65) max ) 0.010 (0.25) 0.007 (0.18) 0.064 (1.63) 0.045 (1.14) 0.0098 (0.249) 0.0040 (0.102) 0.020 (0.51) 0.013 (0.33) 0.157 (3.99) 0.150 (3.81) 0.050 (1.27) typ pin 1 dimensions: inches (mm) 0.050 (1.27) 0.016 (0.40) 8-lead sop (m) 0.008 (0.20) 0.004 (0.10) 0.039 (0.99) 0.035 (0.89) 0.021 (0.53) 0.012 (0.03) r 0.0256 (0.65) typ 0.012 (0.30) r 5 max 0 min 0.122 (3.10) 0.112 (2.84) 0.120 (3.05) 0.116 (2.95) 0.012 (0.03) 0.007 (0.18) 0.005 (0.13) 0.043 (1.09) 0.038 (0.97) 0.036 (0.90) 0.032 (0.81) dimensions: inch (mm) 0.199 (5.05) 0.187 (4.74) mm8 8-pin msop (mm)
mic2025/2075 micrel mic2025/2075 14 march 2000
march 2000 15 mic2025/2075 mic2025/2075 micrel
mic2025/2075 micrel mic2025/2075 16 march 2000 micrel inc. 1849 fortune drive san jose, ca 95131 usa tel + 1 (408) 944-0800 fax + 1 (408) 944-0970 web http://www.micrel.com this information is believed to be accurate and reliable, however no responsibility is assumed by micrel for its use nor for an y infringement of patents or other rights of third parties resulting from its use. no license is granted by implication or otherwise under any patent or pat ent right of micrel inc. ? 2000 micrel incorporated

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