ts 4268 180ma fixed - voltage ultra low ldo 1 / 7 version: b07 sop - 8 general description t s4268 is a 5v low - drop fixed - voltage regulator. the maximum input voltage is 45 v. it can deliver an output current of at least 180ma. t s4268 is short - circuit proof and features temperature protecti on that disables the circuit in the event of impermissibly high temperatures. the watchdog function is disabled as a function of the load, so that a controller is not interrupted during sleep mode by a watchdog reset. application description t s4268 regula tes an input voltage in the range 5.5v ~ 45v. in the event of an output voltage vout < v rt , a reset signal is generated. the wiring of the reset switching threshold input enables the value of v rt to be reduced. the reset delay time can be adjusted using an external capacitor. the integrated watchdog monitors the connected active controller. if there is no positive - going edge at the watchdog input, the reset output is set to low. the reset delay capacitor provides a wide adjustment range for the pulse repeti tion time. the watchdog function is only activated if the load exceeds 8ma. this ensures that a microcontroller is not activated during power - down and the current drain is not increased. the ic is protected against overload and over temperature. features output voltage tolerance < 2% very low current consumption low - drop voltage watchdog settable reset threshold over temperature protection reverse polarity protection short - circuit proof suitable for use in automotive electronics wide temperature range orde ring information part no. package packing ts 4268cs50 rl sop - 8 2.5kpcs / 13 reel pin description pin no. symbol pin description 1 in input voltage . block to ground directly with ceramic capacitor 2 n/c not connected 3 ro reset output. the open col lector output is connected to the 5v output via an integrated resistor of 30k 4 gnd ground 5 rd reset delay. connect a capacitor to ground for delay time adjustment. 6 radj reset switching threshold. for setting the switching threshold, output to ground with voltage divider. if this input is connected to ground, the reset is tr iggered at an output voltage of 4.5v. 7 wi watchdog input . positive - edge - triggered input for monitoring a microcontroller. 8 out output voltage. block to ground with 22 u f capacitor, esr <3 pin definition : 1. in 8. out 2. n/c 7. wi 3. ro 6. radj 4. gnd 5. rd
ts 4268 180ma fixed - voltage ultra low ldo 2 / 7 version: b07 absolute maximum ratings parameter symbol min. max. unit note s input input voltage v in - 30 45 v input current i in internally limited reset output voltage v res - 0.3 7 v current i res internally limited reset delay voltage v rd - 0.3 7 v current i rd internally limited watchdog watchdog input v wi - 0.3 7 v reset input reset threshold v r t - 0.3 7 v output output voltage v out - 0.3 7 v output current i out internally limited ground current i q - 100 50 ma temperatures junction temperature t j - 40 150 storage temperature t stg - 50 150 ? operat ion range parameter symbol min. max. unit notes input voltage v in -- 45 junction temperature t j - 4 0 150 ? thermal resistance parameter symbol min. max. unit notes junction to ambient (soldered) r ja -- 185 (note 1) junction pin r jp -- 72 ? /w (n ote 2) 1. package mounted on pcb 80 x 80 x 1.5mm3, footprint only, zero airflow. 2. measure to pin 2 operation at up to the maximum junction temperature of 150 ? is possible in principle. note, however, operation at the maximum permitted rating could be affect ed the reliability of the device.
ts 4268 180ma fixed - voltage ultra low ldo 3 / 7 version: b07 electrical characteristics (vin=13.5v, - 40 t j 125 c, unless otherwise specified.) parameter test conditions m in t yp m ax u nit output voltage 5m a i l 1 5 0ma , 6v v in 28v 4.90 5.00 5.10 v current limit v out = 0 180 2 50 -- ma quiescent current i q = 0m a i q = 100ma -- -- 300 13 400 20 u a ma dropout voltage (note 1) i l =1 5 0ma -- 250 500 mv line regulation 6v v in 28 v , i l =1 5 0ma -- 10 30 mv load regulation 5m a i l 1 5 0ma -- 10 30 mv reset function reset threshold 4.20 4.50 4.80 v reset adjust threshold 1.28 1.35 1.45 v reset low voltage 1ma external -- 0.20 0.50 v saturation voltage v out < v r t -- 0.03 0.10 v charging current v rd < 1.0v 5 12 18 ua upper reset timing threshold 1.4 1.8 2.2 v reset delay time c r d = 100 nf 10 15 25 ms reset reaction time c rd = 100 nf -- 2 -- us pull - up with resp. to v out 18 30 46 k lower reset timing threshold 0.2 0 0.4 0 0.55 v watchdog input discharge current v rd < 1.0v 1.5 3.5 5.2 ua charging current v rd < 1.0v 5 12 1 8 ua upper timing threshold 1.4 1.8 2.2 v lower timing threshold 0.2 0 0.4 0 0.55 v watchdog period c rd = 100 nf 30 55 75 ms watchdog trigger time c rd = 100 nf 25 40 60 ms activating current activates watchdog 2 8 15 ma slew rate from 20% up to 80% v out 5 -- -- v/ u s n ote 1: drop voltage = v in - v out (measured when the output voltage has dropped 100 mv from the nominal value obtained at 13.5 v input) note 2: the reset output is low in range from v out = 1v to v out , rt
ts 4268 180ma fixed - voltage ultra low ldo 4 / 7 version: b07 circuit description the control amplifier compares a reference voltage, which is kept highly accurate by resistance adjustment, to a voltage that is proportional to the output voltage and drives the base of the series transistor via a buffer. saturation control as a function of t he load current prevents any over - saturation of the power element. if the externally scaled down output voltage at the reset threshold input drops below 1.35 v, the external reset delay capacitor is discharged by the reset generator. if the voltage on the capacitor reaches the lower threshold v st , a reset signal is generated on the reset output and not cancelled again until the upper threshold voltage is exceeded. if the reset threshold input is connected to gnd, reset is triggered at an output voltage of 4 .5 v. a connected microcontroller is monitored by the watchdog logic. if pulses are missing, the rest output is set to low. the pulse sequence time can be set within a wide range with the reset delay capacitor. ts4268 is also incorporates a member of inter nal circuits for protection against: ? over load over temperature reverse polarity block diagram
ts 4268 180ma fixed - voltage ultra low ldo 5 / 7 version: b07 test circuit reset timing the power - on reset delay time is defined by charging time of an external c apacitor c d which can be calculated as follow : c d = ( ? t rd x i d,c ) / ? v definitions: c d = delay capacitor ? t rd = delay time i d,c = charge current, typical 12 ua ? v = v du , typical 1.8 v v du = upper delay switching threshold at c d for reset delay time the reset reaction time trr is the time it takes the vol tage regulator to set the reset out low after the output voltage has dropped below the reset threshold. it is typically 1 us for delay capacitor of 47nf . for other values for c d the reaction time can be estimated using the following equation: trr 20 s/f x c d
ts 4268 180ma fixed - voltage ultra low ldo 6 / 7 version: b07 timing (watchdog disabled) timing (watchdog function)
ts 4268 180ma fixed - voltage ultra low ldo 7 / 7 version: b07 notice specifications of the products displayed herein are subject to change without notice. tsc or anyone on its behalf, assumes no responsibility or liability for any errors or inaccuracies. information contained herein is intended to provide a product description only. no license, express or implied, to any intellectual property rights is granted by this document. except as provided in tsc s terms and conditions of sale for such products, tsc assumes no liability whatsoever, and disclaims any express or implied warranty, relating to sale and/or use of tsc products including liability or warranties re lating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright, or other intellectual property right. the products shown herein are not designed for use in medical, life - saving, or life - sustaining applications. custo mers using or selling these products for use in such applications do so at their own risk and agree to fully indemnify tsc for any damages resulting from such improper use or sale.
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