RT9727A 1 ds9727a-01 april 2011 www.richtek.com pin configurations (top view) sc-70-6 typical application circuit marking information for marking information, contact our sales representative directly or through a richtek distributor located in your area. ordering information note : richtek products are : ` rohs compliant and compatible with the current require- ments of ipc/jedec j-std-020. ` suitable for use in snpb or pb-free soldering processes. n-mosfet load switch controller general description the RT9727A is a load switch controller to control the external n-mosfet load switch. the input voltage range of the RT9727A is from 6v to 25v. the RT9727A adopts the constant power discharge method to discharge the residual storages. besides, the RT9727A also provides enable control function and over temperature protection function. the RT9727A is available in a sc-70-6 package. features z z z z z driver n-mosfet load switch z z z z z input voltage range : 6v to 25v z z z z z constant power discharge z z z z z over temperature protection z z z z z enable control z z z z z rohs compliant and halogen free applications z notebook computers en dc2 vcc gnd ct 4 23 5 6 dc1 en RT9727A vcc v cc gnd 2 4 6 1 dc2 dc1 chip enable ct 3 5 3v source to systrm 5v source to systrm c1 q1 q2 c2 c3 c4 RT9727A package type u6 : sc-70-6 lead plating system g : green (halogen free and pb free)
RT9727A 2 ds9727a-01 april 2011 www.richtek.com pin no. pin name pin function 1 vcc power supply input. 2 gnd ground. 3 ct current source output. there is an internal 10 a current source from vcc to ct. 4 dc1 discharge path w hen en pulls low. 5 dc2 discharge path w hen en pulls low. 6 en chip enable (active high). enable c ontrol of the internal 10 a current source and d cx discharge. functional pin description function block diagram gate control dc2 gate control dc1 thermal protection bias regulator en vcc ct gnd
RT9727A 3 ds9727a-01 april 2011 www.richtek.com electrical characteristics (v cc = 10v, v en = 5v, t a = 25 c, unless otherwise specified) parameter symbol test conditions min typ max unit shutdown current i shdn v cc = 6v to 25v, en = low, dc1 and dc2 = 0 -- 5 10 a quiescent current i q v cc = 6v to 25v, en = high -- 40 65 a power on reset threshold v ccr_th v cc rising 3.8 4.2 4.6 v power on reset hysteresis v cc_hys -- 0.25 -- v ct output ct source current i ctsr en = high, ct = 0v 7 10 13 a ct sink current i ctsk en = low, ct = 0.5v 200 -- -- a discharge current en = low, dcx = 5v 18 -- -- en = low, dcx = 3.3v 20 -- -- dis charge c urrent i dcx en = low, dcx = 1.6v 50 -- -- ma thermal shutdown thermal shutdown t shdn -- 160 -- c thermal shutdown hysteresis t shdn_hys -- 20 -- c logic input logic-high v ih rising 2.4 -- -- en threshold voltage logic-low v il falling -- -- 0.8 v absolute maximum ratings (note 1) z vcc, ct to gnd ----------------------------------------------------------------------------------------------------------- ? 0.3v to 28v z en, dc1, dc2 to gnd ---------------------------------------------------------------------------------------------------- ? 0.3v to 6v z power dissipation, p d @ t a = 25 c sc-70-6 ---------------------------------------------------------------------------------------------------------------------- 0.3w z package thermal resistance (note 2) sc-70-6, ja ---------------------------------------------------------------------------------------------------------------- 333 c/w z lead temperature (soldering, 10 sec.) ------------------------------------------------------------------------------- 260 c z junction temperature ----------------------------------------------------------------------------------------------------- 150 c z storage temperature range -------------------------------------------------------------------------------------------- ? 65 c to 150 c z esd susceptibility (note 3) hbm (human body mode) ---------------------------------------------------------------------------------------------- 2kv mm (ma chine mode) ------------------------------------------------------------------------------------------------------ 200v recommended operating conditions (note 4) z supply input voltage, v cc ----------------------------------------------------------------------------------------------- 6v to 25v z junction temperature range -------------------------------------------------------------------------------------------- ? 40 c to 125 c z ambient temperature range -------------------------------------------------------------------------------------------- ? 40 c to 85 c
RT9727A 4 ds9727a-01 april 2011 www.richtek.com note 1. stresses listed as the above " absolute maximum ratings " may cause permanent damage to the device. these are for stress ratings. functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. exposure to absolute maximum rating conditions for extended periods may remain possibility to affect device reliability. note 2. ja is measured in the natural convection at t a = 25 c on a low effective thermal conductivity single layer test board of jedec 51-3 thermal measurement standard. note 3. devices are esd sensitive. handling precaution is recommended. note 4. the device is not guaranteed to function outside its operating conditions.
RT9727A 5 ds9727a-01 april 2011 www.richtek.com typical operating characteristics shutdown current vs. input voltage 0 2 4 6 8 10 5 7 9 1113151719212325 input voltage (v) shutdown current ( a) 1 v en = 0.5v ct source current vs. input voltage 7 8 9 10 11 12 13 5 7 9 1113151719212325 input voltage (v) ct source current ( a) v en = 5v quiescent current vs. input voltage 40 42 44 46 48 50 5 7 9 1113151719212325 input voltage (v) quiescent current ( a ) v en = 5v ct sink current vs. input voltage 145.0 145.4 145.8 146.2 146.6 147.0 5 7 9 1113151719212325 input voltage (v) ct sink current ( a ) v en = 0v, v ct = 0.5v quiescent current vs. temperature 35 40 45 50 55 60 -50 -25 0 25 50 75 100 125 temperature (c) quiescent current ( a ) v cc = 6v v cc = 25v v en = 5v shutdown current vs. temperature 0 2 4 6 8 10 -50 -25 0 25 50 75 100 125 temperature (c) shutdown current ( a) 1 v cc = 25v v cc = 6v v en = 0.5v
RT9727A 6 ds9727a-01 april 2011 www.richtek.com discharge current vs. temperature 0 10 20 30 40 50 60 70 80 -50-25 0 25 50 75100125 temperature (c) discharge current (ma ) v dcx = 1.6v v dcx = 3.3v v dcx = 5v v en = 0v discharge current vs. system residual voltage 0 10 20 30 40 50 60 70 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 system residual voltage (v) vdcx discharge current (ma ) v en = 0v, c out = 300 f vdcx discharge characteristic 0 1 2 3 4 5 6 0 20406080100 time (ms) system residual voltage (v) 1 c out = 300 f ct sink current vs. temperature 80 100 120 140 160 180 200 -50 -25 0 25 50 75 100 125 temperature (c) ct sink current ( a ) v cc = 25v v cc = 6v v en = 0v, v ct = 0.5v ct source current vs. temperature 7 8 9 10 11 12 13 -50 -25 0 25 50 75 100 125 temperature (c) ct source current ( a) v cc = 25v v cc = 6v v en = 5v
RT9727A 7 ds9727a-01 april 2011 www.richtek.com applications information the RT9727A is a load switch with wide input voltage range from 6v to 25v. it provides two paths for discharging the residual voltage when system shutdown. besides, the external mosfet switch on/off can be controlled by an internal current source from the ct pin to the gate of the mosfet switch. a novel control is implemented for nearly constant power to discharge the system residual voltages. enable & por power-on reset (por) occurs when the input voltage rises above to approximately 4.5v, the RT9727A will be turned on once the en pin voltage is higher than 2.4v. after the RT9727A is turned on, there is 10 a (typ.) current flows from ct pin to the gate of the external mosfet, while both dcx pin discharge mosfet are off. discharge operation when en is low, the RT9727A will discharge the system residual voltage using internal mosfet connected between the dcx and gnd, while ct pin is pulled low. the discharge current depends on the voltage at the dcx pin. while both of the voltages at the dc1 and dc2 pins are lower than 0.5v, the RT9727A will fully turn the internal mosfet on to pull the dcx pins low. thermal protection the RT9727A provides thermal shutdown detection to protect the device from over-heating in discharge mode. once the junction temperature reaches 160 c, the RT9727A will stop discharging until the junction temperature is recovered. thermal considerations for continuous operation, do not exceed absolute maximum operation junction temperature. the maximum power dissipation depends on the thermal resistance of ic package, pcb layout, the rate of surroundings airflow and temperature difference between junction to ambient. the maximum power dissipation can be calculated by following formula : p d(max) = (t j(max) ? t a ) / ja where t j(max) is the maximum operation junction temperature, t a is the ambient temperature and the ja is the junction to ambient thermal resistance. for recommended operating condition specification of RT9727A, the maximum junction temperature is 125 c and t a is the maximum ambient temperature. the junction to ambient thermal resistance ja is layout dependent. for sc-70-6 packages, the thermal resistance ja is 333 c/w on the standard jedec 51-3 single layer thermal test board. the maximum power dissipation at t a = 25 c can be calculated by following formula : p d(max) = (125 c ? 25 c) / (333 c /w) = 0.3w for sc-70-6 package the maximum power dissipation depends on operating ambient temperature for fixed t j(max) and thermal resistance ja . for RT9727A package, the figure 1 of derating curves allows the designer to see the effect of rising ambient temperature on the maximum power dissipation allowed. figure 1. derating curves for RT9727A package 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0 25 50 75 100 125 ambient temperature (c) maximum power dissipation (w) 1 single layer pcb sc-70-6
RT9727A 8 ds9727a-01 april 2011 www.richtek.com figure 2. pcb layout guide layout consideration for best performance of the RT9727A, the following guidelines must be followed : ` input capacitor should be placed close to the ic and connected to ground plane to reduce noise coupling. ` keep the main current traces as short and wide as possible. the input capacitor should be placed as close as possible to the ic. c in the main current trace should be as short and wide as possible. en dc2 vcc gnd ct 4 2 3 5 6 dc1
RT9727A 9 ds9727a-01 april 2011 www.richtek.com richtek technology corporation headquarter 5f, no. 20, taiyuen street, chupei city hsinchu, taiwan, r.o.c. tel: (8863)5526789 fax: (8863)5526611 information that is provided by richtek technology corporation is believed to be accurate and reliable. richtek reserves the ri ght to make any change in circuit design, specification or other related things if necessary without notice at any time. no third party intellectual property inf ringement of the applications should be guaranteed by users when integrating richtek products into any application. no legal responsibility for any said applications i s assumed by richtek. richtek technology corporation taipei office (marketing) 5f, no. 95, minchiuan road, hsintien city taipei county, taiwan, r.o.c. tel: (8862)86672399 fax: (8862)86672377 email: marketing@richtek.com a a1 e b b d c h l sc-70-6 surface mount package dimensions in millimeters dimensions in inches symbol min max min max a 0.800 1.100 0.031 0.044 a1 0.000 0.100 0.000 0.004 b 1.150 1.350 0.045 0.054 b 0.150 0.400 0.006 0.016 c 1.800 2.450 0.071 0.096 d 1.800 2.250 0.071 0.089 e 0.650 0.026 h 0.080 0.260 0.003 0.010 l 0.210 0.460 0.008 0.018 outline dimension
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