View RT9167A_810391.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

rt9167/a ds9167/a-14 june 2003 www.richtek.com 1 low-noise, fixed output voltage, 200ma/500ma ldo regulator general description the rt9167/a is a 200ma/500ma low dropout and low noise micropower regulator suitable for portable applications. the output voltages range from 1.5v to 5.0v in 100mv increments and 2% accuracy. the rt9167/a is designed for use with very low esr capacitors. the output remains stable even with 1 f ceramic output capacitor. the rt9167/a uses and internal pmos as the pass device, which does not cause extra gnd current in heavy load and dropout conditions. the shutdown mode of nearly zero operation current makes the ic suitable for battery-power devices. other features include a reference bypass pin to improve low noise performance, current limiti ng, and over temperature protection. ordering information rt9167/a- marking information for marking information, contact our sales representative directly or through a richtek distributor located in your area, otherwise visit our website for detail. features stable with low-esr output capacitor low dropout voltage (220mv and 200ma) low operation current - 80 a typical shutdown function low noise output low temperature coefficient current and thermal limiting custom voltage available sot-25 and sop-8 packages applications cellular telephones laptop, notebook, and palmtop computers battery-powered equipment hand-held equipment pin configurations part number pin configurations rt9167/a- cb (plastic sot-25) top view 1. in 2. gnd 3. shdn 4. bp 5. out rt9167/a- cbr (plastic sot-25) top view 1. out 2. gnd 3. in 4. shdn 5. bp rt9167/a- cs (plastic sop-8) top view operating temperature range c: commercial standard package type b : sot-25 type i br : sot-25 type ii s : sop-8 output voltage 15 : 1.5v 16 : 1.6v : 49 : 4.9v 50 : 5.0v 2h : 2.85v 500ma output current 200ma out p ut current 54 3 2 1 54 3 2 1 shdn in out bp gnd gnd gnd gnd 1 2 3 4 8 7 6 5
rt9167/a www.richtek.com ds9167/a-14 june 2003 2 pin description pin name pin function in input gnd ground shdn active low shutdown input bp reference noise bypass out output function block diagram typical application circuit rt9167/ a on off gnd in out v out c bp 10nf c out 1 f v in c in 1 f shdn bp rt9167/ a on off gnd in out v out c bp 10nf c out 1 f v in c in 1 f shdn bp current-limit and thermal protection mos driver + - out shutdown and logic control r1 r2 in error amplifier vref bp shdn gnd
rt9167/a ds9167/a-14 june 2003 www.richtek.com 3 absolute maximum ratings input voltage 8v power dissipation, p d @ t a = 25 c sot-25 0.25w sop-8 0.625w operating junction temperature range ? 40 c to 125 c storage temperature range ? 65 c to 150 c package thermal resistance sot-25, ja 250 c/w sop-8, ja 160 c/w lead temperature (soldering, 5 sec.) 260 c electrical characteristics (v in = 5.0v, c in = 1 f, c out = 1 f, t a = 25 c, unless otherwise specified) parameter symbo test conditions min typ max units 2.9 -- 7 input voltage range v in i l = 50ma 2.7 -- 7 v output voltage accuracy ? v out i l = 1ma -2 -- +2 % rt9167 200 -- -- maximum output current RT9167A i max 500 -- -- ma rt9167 -- 300 -- current limit RT9167A i limit r load = 1 ? -- 700 -- ma rt9167/a no load -- 80 150 rt9167 i out = 200ma -- 90 150 gnd pin current RT9167A i g i out = 500ma -- 90 150 a rt9167/a i out = 1ma -- 1.1 5 rt9167/a i out = 50ma -- 55 100 rt9167/a i out = 200ma -- 220 300 dropout voltage (note) (v out (nominal) 3.0v version) RT9167A v drop i out = 500ma -- 600 750 mv line regulation ? v line v in = (v out +0.15) to 7v, i out =1ma -- -- 6 mv/v rt9167 i out = 0ma to 200ma -- -- 25 load regulation RT9167A ? v load i out = 0ma to 500ma -- -- 35 mv shdn input high threshold v ih v in = 3v to 5.5v 1.6 -- -- v shdn input low threshold v il v in = 3v to 5.5v -- -- 0.4 v shdn bias current i sd -- -- 100 na shutdown supply current i gsd v out = 0v -- 0.01 1 a thermal shutdown temperature t sd -- 155 -- c output noise e no c bp = 10nf, c out = 10 f -- 350 -- nv hz ripple rejection psrr f = 100hz, c bp = 10nf, c out = 10 f -- 58 -- db notes: dropout voltage definition: v in - v out when v out is 50 mv below the value of v out at v in = v out + 0.5v
rt9167/a www.richtek.com ds9167/a-14 june 2003 4 typical operating charateristics output voltage vs. temp. 3.25 3.26 3.27 3.28 3.29 3.30 3.31 3.32 3.33 -50 -25 0 25 50 75 100 125 150 output voltage (v) temperature ( ) v out = 3.3v c gnd current vs. temp. 0 15 30 45 60 75 90 105 120 -50 -25 0 25 50 75 100 125 150 temperature ( ) gnd current ( a) c v out = 3.3v current limit vs. temp. 100 200 300 400 500 600 700 800 900 -50 -25 0 25 50 75 100 125 150 current limit (ma) temperature ( ) c RT9167A v out = 3.3v current limit vs. temp. 0 60 120 180 240 300 360 420 480 -50 -25 0 25 50 75 100 125 150 current limit (ma) temperature ( ) c rt9167 psrr 0 10 20 30 40 50 60 70 10 100 1000 10000 100000 100000 0 frequency (khz) psrr (db) i load = 1ma, c out = 4.7f v out = 3.3v, c bp = 10nf 10 100 1k 10k 100k 1m dropout voltage vs. output current 0 50 100 150 200 250 300 0 25 50 75 100 125 150 175 200 output current (ma) dropout voltage (v) v out = 3.3v 85 c 25 c -40 c (mv)
rt9167/a ds9167/a-14 june 2003 www.richtek.com 5 t t t 1 > 2 > 50 1 -50 60 40 20 0 -20 load transient response time ( 50 f c in = 10 f c bp = 10nf v out = 3.0v v in = 4v t t t 1 > 2 > 50 1 -50 60 40 20 0 -20 load transient response time ( 50 f c in = 10 f c bp = 10nf v out = 3.0v v in = 4v t t t 1 2 > 5 4 150 100 50 0 -50 line transient response time (1ms/div) input voltage (v) output voltage (mv) c out = 1 f v out = 3.0v loading = 1ma c bp = 10nf t t t 1 2 > 5 4 150 100 50 0 -50 line transient response time ( 500 f v out = 3.0v loading = 1ma c bp = 10nf t t t 1 2 > 5 4 150 100 50 0 -50 line transient response time (1ms/div) input voltage (v) output voltage (mv) c out = 1 f v out = 3.0v loading = 50ma c bp = 10nf t t t 1 2 > 5 4 60 40 20 0 -20 line transient response time ( 500 f v out = 3.0v loading = 50ma c bp = 10nf
rt9167/a www.richtek.com ds9167/a-14 june 2003 6 applications guides capacitor selection and regulator stability like any low-dropout regulator , the external capacitors used with the rt9167/a must be carefully selected for regulator stability and performance. using a capacitor whose value is > 1 f on the rt9167/a input and the amount of capacitance can be increased without limit. the input capacitor must be located a distance of not more than 0.5" from the input pin of the ic and returned to a clean analog ground. any good quality ceramic or tantalum can be used for this capacitor. the capacitor with larger value and lower esr (equivalent series resistance) provides better psrr and line-transient response. the output capacitor must meet both requirements for minimum amount of capacitance and esr in all ldos application. the rt9167/a is designed specifically to work with low esr ceramic output capacitor in space-saving and performance consideration. using a ceramic capacitor whose value is at least 1uf with esr is > 5m ? on the rt9167/a output ensures stability. the rt9167/a st ill works well with output capacitor of other types due to the wide stable esr range. fig.1 shows the curves of allowable esr range as a function of load current for various output voltages and capacitor values. output capacitor of larger capacitance can reduce noise and improve load-transient response, stability, and psrr. the output capacitor should be located not more than 0.5" from the v out pin of the rt9167/a and returned to a clean analog ground. note that some ceramic dielectrics exhibit large capacitance and esr variation with temperature. it may be necessary to use 2.2 f or more to ensure stability at temperatures belo w -10c in this case. also, tantalum capacitors, 2.2 f or more may be needed to maintain capacitance and esr in the stable region for strict application environment. tantalum capacitors maybe suffer failure due to surge current when it is connected to a low-impedance source of power (like a battery or very large capacitor). if a tantalum capacitor is used at the input, it must be guaranteed to have a surge cu rrent rating sufficient for the application by the manufacture. use a 10nf bypass capacitor at bp for low output voltage noise. the capacitor, in conjunction with an internal 200k ? resistor, which connects bypass pin and the band-gap reference, creates an 80hz low-pass filter for noise reduction. increasing the capacitance will slightly decrease the output noise, but increase the start-up time. the capacitor connected to the bypass pin for noise reduction must have very low leakage. this capacitor leakage current causes the output voltage to decline by a proportional amount to the current due to the voltage drop on the internal 200k ? resistor. fig. 2 shows the power on response. region of stable cout esr v.s load current 0.001 0.01 0.1 1 10 100 0 40 80 120 160 200 load current (ma) cout esr ( ) c out = 4.7 f c out = 1 f ? region of stable c out esr vs. load current 0 40 80 120 160 200 c() c out esr ( ? ) 100 0.001 0.01 0.1 1 10 ( ? ) fig. 1 stable region unstable region unstable region
rt9167/a ds9167/a-14 june 2003 www.richtek.com 7 load-transient considerations the rt9167/a load-transient response graphs (see typical operating characteristics) show two components of the output response: a dc shift from the output impedance due to the load current change, and the transient response. the dc shift is quite small due to the excellent load regulation of the ic. typical output voltage transient spike for a step change in the load current from 0ma to 50ma is tens mv, depending on the esr of the output capacitor. increasing the output capacitor?s value and decreasing the esr attenuates the overshoot. shutdown input operation the rt9167/a is shutdown by pulling the shdn input low, and turned on by driving the input high. if this feature is not to be used, the shdn input should be tied to vin to keep the regulator on at all times (the shdn input must not be left floating). to ensure proper operation, the signal source used to drive the shdn input must be able to swing above and below the specified turn-on/turn-off voltage thresholds which guarantee an on or off state (see electrical characteristics). the on/off signal may come from either cmos output, or an open-collector output with pull-up resistor to the rt9167/a input voltage or another logic supply. the high-level voltage may exceed the rt9167/a input voltage, but must remain within the absolute maximum ratings for the shdn pin. internal p-channel pass transistor the rt9167/a features a typical 1.1 ? p-channel mosfet pass transistor. it provides several advantages over similar designs using pnp pass transistors, including longer battery life. the p-channel mosfet requires no base drive, which reduces quiescent current considerably. pnp-based regulators waste considerable current in dropout when the pass transistor saturates. they also use high base-drive currents under large loads. the rt9167/a does not suffer from these problems and consume only 80 a of quiescent current whether in dropout, light-load, or heavy-load applications. input-output (dropout) voltage a regulator?s minimum input-output voltage differential (or dropout voltage) determines the lowest usable supply voltage. in battery-powered systems, this will determine the useful end-of-life battery voltage. because the rt 9167/a uses a p-channel mosfet pass transistor, the dropout voltage is a function of drain-to-source on-resistance [r ds(on) ] multiplied by the load current. reverse current path the power transistor used in the rt9167/a has an inherent diode connected bet ween the regulator input and output (see fig.3). if the output is forced above the input by more than a diode-drop, this diode will become forward biased and cu rrent will flow from the v out terminal to v in . this diode will also be turned on by abruptly stepping the input voltage to a value below the output voltage. to prevent regulator mis-operation, a schottky diode should be used in any applications where input/output voltage conditions can cause the internal diode to be turned on (see fig.4). as shown, the schottky diode is connected in parallel with the internal parasitic diode and prevents it from being turned on by limiting the voltage drop across it to about 0.3v. < 100 ma to prevent damage to the part. 10.0 15.0 0 5.0 c bp = 10nf time (ms) fig. 2 c bp = 1nf vo l tage (0 . 5 v / div ) v out =3.0v
rt9167/a www.richtek.com ds9167/a-14 june 2003 8 current limit and thermal protection the rt9167 includes a current limit which monitors and controls the pass transistor?s gate voltage limiting the output current to 300ma typ. (700ma typ. for RT9167A). thermal-overl oad protection limits total power dissipation in the rt9167/a. when the junction temperature exceeds t j = +155c, the thermal sensor signals the shutdown logic turning off the pass transistor and allowing the ic to cool. the thermal sensor will turn the pass transistor on again after the ic?s junction temperature cools by 10c, resulting in a pulsed output during continuous thermal-overload conditions. thermal-overloaded protection is designed to protect the rt9167/a in the event of fault conditions. do not exceed the absolute maximum junction-temperature rating of t j = +150c for continuous operation. the output can be shorted to ground for an indefinite amount of time without damaging the part by cooperation of current limit and thermal protection. operating region and power dissipation the maximum power dissipation of rt9167/a depends on the thermal resistance of the case and circuit board, the temperature difference between the die junction and ambient air, and the rate of airflow. the power dissipation across the device is p = i out (v in - v out ). the maximum power dissipation is: pmax = (t j - t a ) / ja where t j - t a is the temperature difference between the rt9167/a die junction and the surrounding environment, ja is the thermal resistance from the junction to the surrounding environment. the gnd pin of the rt9167/a performs the dual function of providing an electrical connection to ground and channeling heat away. connect the gnd pin to ground using a large pad or ground plane. fi g . 3 v in v ou t fig. 4 v in v ou t
rt9167/a ds9167/a-14 june 2003 www.richtek.com 9 package information dimensions in millimeters dimensions in inches symbol min max min max a 0.889 1.295 0.035 0.051 a1 0.000 0.152 0.000 0.006 b 1.397 1.803 0.055 0.071 b 0.356 0.559 0.014 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 0.102 0.254 0.004 0.010 l 0.356 0.610 0.014 0.024 sot- 25 surface mount package a a1 e b b d c h l
rt9167/a www.richtek.com ds9167/a-14 june 2003 10 dimensions in millimeters dimensions in inches symbol min max min max a 4.801 5.004 0.189 0.197 b 3.810 3.988 0.150 0.157 c 1.346 1.753 0.053 0.069 d 0.330 0.508 0.013 0.020 f 1.194 1.346 0.047 0.053 h 0.178 0.254 0.007 0.010 i 0.102 0.254 0.004 0.010 j 5.791 6.198 0.228 0.244 m 0.406 1.270 0.016 0.050 8?lead sop plastic package a b j f h m c d i
rt9167/a ds9167/a-14 june 2003 www.richtek.com 11
rt9167/a www.richtek.com ds9167/a-14 june 2003 12 richtek technology corp. headquarter 5f, no. 20, taiyuen street, chupei city hsinchu, taiwan, r.o.c. tel: (8863)5526789 fax: (8863)5526611 richtek technology corp. taipei office (marketing) 8f-1, no. 137, lane 235, paochiao road, hsintien city taipei county, taiwan, r.o.c. tel: (8862)89191466 fax: (8862)89191465 email: marketing@richtek.com

▲Up To Search▲

Price & Availability of RT9167A

	To Download RT9167A Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .