february 1999 toko, inc. page 1 advanced information features n low dropout voltage n very low quiescent current (50 m a maximum) n internal bandgap reference n regulates down to 1.8 v n short circuit protection n very low standby current (1 m a maximum) n miniature package (sot-23-5) block diagram tkxxxxx gnd v in nc v out control tk6xxxx s ordering information tape/reel code tl: tape left package code s: sot-23-5 tape/reel code package code voltage code 18 = 1.8 v 33 = 3.3 v 55 = 5.5 v 20 = 2.0 v 35 = 3.5 v 60 = 6.0 v 25 = 2.5 v 40 = 4.0 v 28 = 2.8 v 45 = 4.5 v 30 = 3.0 v 50 = 5.0 v voltage code description the device is a low dropout linear regulation housed in a small sot-23-5 package, rated at 500 mw. an internal p channel pass transistor is used in order to achieve low dropout voltage. the device has extremely low quiescent current (max 50 m a). the device offers high precision output voltage of 2% at over temperature. the low quiescent current and dropout voltage make this part ideal for battery powered applications. in the standby mode when the device is disabled, the linear regulator only draws 1 m a (max). applications n battery powered systems n cellular telephones n pagers n toys n radio control systems n low voltage systems n personal communications systems n portable instrumentation n portable consumer equipment cmos ldo regulator with high active control advanced information control gnd v in v out + - bandgap reference control circuit + - current limit
page 2 february 1999 toko, inc. advanced information absolute maximum ratings all pins except gnd ................................................... 9 v power dissipation (note 1) ................................ 500 mw storage temperature range ................... -55 to +150 c operating temp. range ..............................-30 to +80 c junction temperature ........................................... 150 c electrical characteristics test conditions: v in = v out(typ) + 1 v, t a = 25 c, unless otherwise specified. note 1: power dissapation is 500 mw when mounted as recommended (150 mw in free air). derate at 1.8 mw/ c for operation above 25 c. note 2: v out = 1.8 v to 6 v, 0.1 v step. l o b m y sr e t e m a r a ps n o i t i d n o c t s e tn i mp y tx a ms t i n u v n i y l p p u s t u p n i 8v i q t n e r r u c t n e c s e i u qd a o l o n0 30 5a i y b t s t n e r r u c y b d n a t sv n i f f o t u p t u o , v 8 =1a i t u o t n e r r u c t u p t u o0 5a m v t u o e g a t l o v t u p t u ot , 2 e t o n a i , c 0 8 + o t 0 3 - = t u o a m 1 =% 2 -v t u o % 2v g e r d a o ln o i t a l u g e r d a o li t u o a m 1 =a m 0 5 o t0 0 2v m g e r e n i ln o i t a l u g e r e n i lv ) p y t ( t u o v 5 . 0 + v n i i , v 8 t u o a m 1 =d b tv m v p o r d e g a t l o v t u o p o r di t u o a m 0 5 =5 50 0 2v m s n o i t a c i f i c e p s l a n i m r e t l o r t n o c i t n o c t n e r r u c l o r t n o cv t n o c n o t u p t u o , v 5 . 1 =d b ta v t n o c ) n o (n o e g a t l o v l o r t n o cn o t u p t u o5 . 1v v t n o c ) f f o (f f o e g a t l o v l o r t n o cf f o t u p t u o5 2 . 0v
february 1999 toko, inc. page 3 advanced information definition and explanation of technical terms output voltage (v out ) the output voltage is specified with v in = (v out(typ) + 1 v) and i out = 1 ma. dropout voltage (v drop ) the dropout voltage is the difference between the input voltage and the output voltage at which point the regulator starts to fall out of regulation. below this value, the output voltage will fall as the input voltage is reduced. it is dependent upon the load current and the junction temperature. output current (i out ) normal operating output current. this is limited by package power dissipation. line regulation (line reg) line regulation is the ability of the regulator to maintain a constant output voltage as the input voltage changes. the line regulation is specified as the input voltage is changed from v in = v out + 0.5 v to v in = 8 v. load regulation (load reg) load regulation is the ability of the regulator to maintain a constant output voltage as the load current changes. it is a pulsed measurement to minimize temperature effects with the input voltage set to v in = v out +1 v. the load regulation is specified under output current step conditions of 1 ma to 50 ma. quiescent current (i q ) the quiescent current is the current which flows through the ground terminal under no load conditions (i out = 0 ma). standby current (i stby ) standby current is the current which flows into the regulator when the output is turned off by the control function (v cont = 0 v). it is measured with v in = 8 v. sensor circuits overcurrent sensor the overcurrent sensor protects the device if the output is shorted to ground. package power dissipation (p d ) this is the power dissipation level at which the thermal sensor is activated. the ic contains an internal thermal sensor which monitors the junction temperature. when the junction temperature exceeds the monitor threshold of 150 c, the ic is shut down. the junction temperature rises as the difference between the input power (v in x i in ) and the output power (v out x i out ) increases. the rate of temperature rise is greatly affected by the mounting pad configuration on the pcb, the board material, and the ambient temperature. when the ic mounting has good thermal conductivity, the junction temperature will be low even if the power dissipation is great. when mounted on the recommended mounting pad, the power dissipation of the sot-23-5 is increased to 500 mw. for operation at ambient temperatures over 25 c, the power dissipation of the sot-23-5 device should be derated at 4.0 mw/ c. to determine the power dissipation for shutdown when mounted, attach the device on the actual pcb and deliberately increase the output current (or raise the input voltage) until the thermal protection circuit is activated. calculate the power dissipation of the device by subtracting the output power from the input power. these measurements should allow for the ambient temperature of the pcb. the value obtained from p d /(150 c - t a ) is the derating factor. the pcb mounting pad should provide maximum thermal conductivity in order to maintain low device temperatures. as a general rule, the lower the temperature, the better the reliability of the device. the thermal resistance when mounted is expressed as follows: t j = 0 ja x p d + t a for toko ics, the internal limit for junction temperature is 150 c. if the ambient temperature (t a ) is 25 c, then: 150 c = 0 ja x p d + 25 c 0 ja = 125 c / p d
page 4 february 1999 toko, inc. advanced information definition and explanation of technical terms (cont.) p d is the value when the thermal protection circuit is activated. a simple way to determine p d is to calculate v in x i in when the output side is shorted. input current gradually falls as temperature rises. you should use the value when thermal equilibrium is reached. the range of usable currents can also be found from the graph below. procedure: 1) find p d 2) p d1 is taken to be p d x (~0.8 - 0.9) 3) plot p d1 against 25 c 4) connect p d1 to the point corresponding to the 150 c with a straight line. 5) in design, take a vertical line from the maximum operating temperature (e.g., 75 c) to the derating curve. 6) read off the value of p d against the point at which the vertical line intersects the derating curve. this is taken as the maximum power dissipation, d pd . the maximum operating current is: i out = (d pd / (v in(max) - v out ) sot-23-5 power dissipation curve p d d pd 25 50 75 150 (mw) t a ( c) 3 6 5 4 0 50 100 150 t a ( c) p d ( m w) 0 100 500 mounted as shown free air 200 300 400
february 1999 toko, inc. page 5 advanced information application information
page 6 february 1999 toko, inc. advanced information 0.95 0.95 0.95 0.95 e m 0.1 2.9 1.6 1.1 0.15 0.4 2.8 1.90 2.4 e' recommended mount pad 1 23 4 5 1.0 0.7 (0.8) 0 - 0.1 (0.6) (0.6) 1.4 max e e e 0.1 e1 0 - 15 max marking 0.3 +0.15 - 0.05 dimensions are shown in millimeters tolerance: x.x = 0.2 mm (unless otherwise specified) +0.15 -0.05 marking information part number marking sot-23-5 package outline printed in the usa ? 1999 toko, inc. all rights reserved toko america regional offices toko america, inc. headquarters 1250 feehanville drive, mount prospect, illinois 60056 tel: (847) 297-0070 fax: (847) 699-7864 ic-216-tkxxxxx 0798o0.0k visit our internet site at http://www.tokoam.com the information furnished by toko, inc. is believed to be accurate and reliable. however, toko reserves the right to make chang es or improvements in the design, specification or manufacture of its products without further notice. toko does not assume any liability arising from the application or use of any product or circu it described herein, nor for any infringements of patents or other rights of third parties which may result from the use of its products. no license is granted by implication or otherwise under any patent or patent rights of toko, inc. western regional office toko america, inc. 2480 north first street , suite 260 san jose, ca 95131 tel: (408) 432-8281 fax: (408) 943-9790 midwest regional office toko america, inc. 1250 feehanville drive mount prospect, il 60056 tel: (847) 297-0070 fax: (847) 699-7864 eastern regional office toko america, inc. 107 mill plain road danbury, ct 06811 tel: (203) 748-6871 fax: (203) 797-1223 semiconductor technical support toko design center 4755 forge road colorado springs, co 80907 tel: (719) 528-2200 fax: (719) 528-2375
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