RT9828 1 ds9828-02 april 2011 www.richtek.com features z z z z z high accuracy 1.5% z z z z z low supply current 6ua z z z z z quick reset within 20us z z z z z built-in 55ms recovery delay z z z z z low functional supply voltage 0.9v z z z z z dual n-channel open-drain output z z z z z small sot-23-6 packages z z z z z rohs compliant and 100% lead (pb)-free applications z computers z controllers z intelligent instruments z critical up and uc power monitoring z portable/battery-powered equipment dual micro-power voltage detectors general description the RT9828 is a micro-power voltage detector supervising the power supply voltage level for microprocessors (up) or digital systems. it provides internally fixed threshold levels ranging from 1.2v to 5v, which covers most digital applications. it features low supply current of 6ua. the RT9828 performs supervisory function by sending out a reset signal whenever the v dd voltage falls below a preset threshold level. this reset signal will last the whole period before v dd recovering. once the v dd exceeds the threshold level, the reset signal will be released after a certain delay time. the RT9828 is available in sot-23-6 package. marking information for marking information, contact our sales representative directly or through a richtek distributor located in your area. 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. ordering information (top view) sot-23-6 pin configurations vdd1 nc gnd vdd2 4 23 5 6 reset2 reset1 RT9828 package type e : sot-23-6 lead plating system p : pb free g : green (halogen free and pb free) - threshold voltage : reset1/reset2 wp : 1.6v/3.0v gp : 1.8v/3.0v
RT9828 2 ds9828-02 april 2011 www.richtek.com function block diagram functional pin description pin no. pin name pin function 1 vdd1 input of detector1. 2 nc no internal connection. it should be floating. 3 reset2 active low open-drain reset pin of detector2. 4 vdd2 input of detector2. 5 gnd ground. 6 reset1 active low open-drain reset pin of detector1. code c b f w g d y h e j k voltage 1.2 1.3 1.5 1.6 1.8 1. 85 1.9 2 2.1 2.5 2.6 code t l m n v p q r s t -- voltage 2.65 2.7 2.8 2.85 2.9 3 3.1 3.2 3.3 5 -- available voltage version typical application circuit reset2 reset1 timer vset1 threshold voltage setting por power on reset cmp n mos gnd vdd1 timer vset2 threshold voltage setting por power on reset cmp n mos vdd2 gnd vdd1 RT9828 100k reset1 v dd1 vdd2 reset2 v dd2 100k reset2 reset1 1 3 4 5 6
RT9828 3 ds9828-02 april 2011 www.richtek.com absolute maximum ratings (note 1) z input voltage (with respect to gnd) v dd1 /v dd2 --------------------------------------------------------------------------------------------------------------- ? 0.3v to 6v z all other inputs -------------------------------------------------------------------------------------------------------- ? 0.3v to v dd + 0.3v z input current, i dd1 /i dd2 ----------------------------------------------------------------------------------------------- 20ma z power dissipation, p d @ t a = 25 c sot-23-6 ---------------------------------------------------------------------------------------------------------------- 0.4w z package thermal resistance (note 2) sot-23-6, ja ----------------------------------------------------------------------------------------------------------- 250 c/w z lead temperature (soldering, 10se c.) ---------------------------------------------------------------------------- 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 electrical characteristics (v dd = 3v, t a = 25 c, unless otherwise specified) parameter symbol test conditions min typ max units input voltage v dd1 / v dd2 0.9 -- 6 v supply current i vd d1 / i vd d2 v th = 3v, v dd = 4.5v -- 6 16 ua threshold voltage accuracy v th ? 1.5 -- +1.5 % v dd drop to reset delay t rd drop = v th ? 125mv -- 20 -- us reset active time out period t rp v dd 1.02 v th -- 55 -- ms reset output voltage low v ol 1.6 = v dd < v th , i sink > 3.5ma -- -- 0.4 v hysteresis width v hys -- 0.01v th -- v recommended operating conditions (note 4) z junction temperature range ---------------------------------------------------------------------------------------- ? 40 c to 125 c z ambient temperature range ---------------------------------------------------------------------------------------- ? 40 c to 85 c 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 single layer thermal conductivity 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.
RT9828 4 ds9828-02 april 2011 www.richtek.com typical operating characteristics nch driv er sink current vs. input voltage 0 5 10 15 20 25 30 35 40 00.511.522.533.5 input voltage (v) nch driver sink current (ma) 80 c 25 c -30 c v th = 3v, v ds = 0.5v nch diver sink current vs. input voltage 0 4 8 12 16 20 0 0.4 0.8 1.2 1.6 2 input voltage (v) nch driver sink current (ma) 80 c 25 c -30 c v th = 1.6v, v ds = 0.5v output voltage vs. input voltage 0 1 2 3 4 5 6 0123456 input voltage (v) output voltage (v) v th = 3v output voltage vs. input voltage 0 1 2 3 4 5 6 0123456 input voltage (v) output voltage (v) v th = 1.6v vdd2 supply current vs. input voltage 0 1 2 3 4 5 0123456 input voltage (v) supply current (ua) 80 c -30 c v th = 3v 25 c vdd1 supply current vs. input voltage 0 1 2 3 4 5 0123456 input voltage (v) supply current (ua) 80 c -30 c v th = 1.6v 25 c
RT9828 5 ds9828-02 april 2011 www.richtek.com power-up reset time-out vs. temperature 0 20 40 60 80 100 -50 -25 0 25 50 75 100 125 temperature power-up reset time-out (ms) v th = 3v v th = 1.6v ( c) power-down reset time-out vs. temperature 10 15 20 25 30 35 40 -50 -25 0 25 50 75 100 125 temperature power-down reset time-out (us) v drop = 200mv v drop = 150mv v drop = 250mv v th = 3v ( c) power-down reset time-out vs. temperature 0 4 8 12 16 20 -50 -25 0 25 50 75 100 125 temperature power-down reset time-out (us) v drop = 200mv v drop = 150mv v drop = 250mv ( c) v th = 1.6v reset threshold deviation vs. temperature 1.5 2.0 2.5 3.0 3.5 -50 -25 0 25 50 75 100 125 temperature reset threshold (v) v th = 3v v th = 1.6v ( c)
RT9828 6 ds9828-02 april 2011 www.richtek.com application information the RT9828 voltage detector monitors the input voltage fo generate a reset signal while the input voltage is lower then the detecting threshold voltage level. the reset pin is an open drain output. it is recommended to connect a pull-up resister between reset pin and v in . figure 1 shows the timming diagram of vdd and reset signals. when vdd is lower than v th , the reset goes low after a short delay time t rd . when vdd is higher than v th with a hystersis (v hys ), the reset will be pulled up after the delay time t rp . the typical value of the delay time t rd and t rp are showed in specification. figure 1. timming diagram v th + v hys v th vdd t rd t rp reset minimum operation voltage 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 125 c, t a is the ambient temperature and the ja is the junction to ambient thermal resistance. for recommended operating conditions specification of RT9828, where t j(max) is the maximum junction temperature of the die (125 c) and t a is the maximum ambient temperature. the junction to ambient thermal resistance ja is layout dependent. for sot-23-6 packages, the thermal resistance ja is 250 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) / (250 c/w) = 0.400w for sot-23-6 packages the maximum power dissipation depends on operating ambient temperature for fixed t j(max) and thermal resistance ja . for RT9828 packages, the figure 2 of derating curves allows the designer to see the effect of rising ambient temperature on the maximum power allowed. figure 2. derating curves for RT9828 packages 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0255075100125 ambient temperature (c) maximum power dissipation (w) single layer pcb sot-23-6
RT9828 7 ds9828-02 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 infringemen t of the applications should be guaranteed by users when integrating richtek products into any application. no legal responsibility for any said applications is assumed b y 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 outline dimension a a1 e b b d c h l sot-23-6 surface mount package dimensions in millimeters dimensions in inches symbol min max min max a 0.889 1.295 0.031 0.051 a1 0.000 0.152 0.000 0.006 b 1.397 1.803 0.055 0.071 b 0.250 0.560 0.010 0.022 c 2.591 2.997 0.102 0.118 d 2.692 3.099 0.106 0.122 e 0.838 1.041 0.033 0.041 h 0.080 0.254 0.003 0.010 l 0.300 0.610 0.012 0.024
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