________________________________________________________________________ http://www.union-ic.com rev.04 jul.2012 1/8 um70xxa voltage detector um70xxa sot23-3 general description the um70xxa series are a set of three-terminal low power voltage detectors implemented in cmos technology. each voltage detector in the series detects a particular fixed voltage ranging from 2.4v to 5v. the voltage detectors consist of a high-precision voltage divider circuit, band gap voltage source, a comparator and an output driver. cmos technology ensures low power consumption. although designed primarily as fixed voltage detect ors, these devices can be used with external components to detect user specified threshold voltages (nmos open drain type only). the um70xxa series are available in sot23-3 package. applications features z battery checkers z level selectors z power failure detectors z microcomputer reset z battery memory backup z non-volatile ram signal storage protectors z low power consumption z low temperature coefficient z built-in high-stability reference source z built-in hysteresis characteristic z sot23-3 package pin configurations top view selection table part number detector voltage hysteresis width tolerance marking code packaging type shipping qty UM7027A 2.7 0.13v 3% n627 um7044a 4.4 0.22v 3% n644 sot23-3 3000pcs/7inch tape & reel note: the output type selection codes are: nmos open drain normal open, active low for example: the um7044a is a 4.4v, nmos open drain active low output. um70xxa xx: voltage rank sot23-3
________________________________________________________________________ http://www.union-ic.com rev.04 jul.2012 2/8 um70xxa output type selection table v dd v det(+) v dd v det(-) a hi-z vss block diagram n channel open drain output (normal open; active low) a type v dd vout type
________________________________________________________________________ http://www.union-ic.com rev.04 jul.2012 3/8 um70xxa absolute maximum ratings (note 1) symbol parameter value unit v dd supply voltage v ss -0.3 to v ss +10 v v out output voltage v ss -0.3 to v dd +0.3 v i o output current 50 ma t j operating junction temperature 0 to +70 c t stg storage temperature range -50 to +125 c p d power consumption 200 mw note 1: these are stress ratings only. str esses exceeding the range specified under ?absolute maximum ratings? may cause substantial damage to the device. functional operation of this device at other conditions beyond those listed in the specification is not implied and prolonged exposure to extreme cond itions may affect device reliability. electrical characteristics UM7027A test conditions symbol parameter vdd conditions min. typ. max. unit v det detection voltage 2.619 2.700 2.781 v v hys hysteresis width 0.02 v det 0.05 v det 0.1 v det v i dd operating current 8v no load 1 2 ua v dd operating voltage 1.5 10 v i ol output sink current 2v v out =0.2v 0.5 1 ma ta v det temperature coefficient 0 ________________________________________________________________________ http://www.union-ic.com rev.04 jul.2012 4/8 um70xxa function description the um70xxa series are a set of voltage det ectors equipped with a high stability voltage reference which is connected to the nega tive input of a comparator-denoted as v ref in the following figure for nmos output voltage detector. when the voltage drop to the positive input of the comparator (i,e,v b ) is higher than v ref, v out goes high, and v b is expressed as v bh =v dd r b / (r a +r b ). if v dd is decreased so that v b falls to a value less than v ref , the comparator output inverts from high to low, v out goes low, v c is high. if v dd falls below the minimum operating voltage, the output becomes undefined. the figure demonstrates the nmos output type with positive output polarity (v out is normally open, active low). the um70xxa series also suppli es options for other output types with active high outputs. application circuits shown are examples of pos itive output polarity (normally open, active low) unless otherwise specified nmos output voltage detector (um70xxa)
________________________________________________________________________ http://www.union-ic.com rev.04 jul.2012 5/8 um70xxa applications circuits microcomputer reset circuit normally a reset circuit is required to protect the microcomputer system from malfunctions due to power fail or power line interruptions. the following examples show how different output configurations perform a reset function in various systems. nmos open drain output application for separate power supply nmos open drain output application with r-c delay power-on reset circuit with several external components, the nmos ope n drain type of the um70xxa series can be used to perform a power-on reset function as shown. um70xxa um70xxa um7044a
________________________________________________________________________ http://www.union-ic.com rev.04 jul.2012 6/8 um70xxa 5v power line monitoring circuit generally, a minimum operating voltage of 4.5v is guaranteed in a 5v power line system. the um7044a is recommended for use as 5v power line monitoring circuit. 5v power line monitor with power-on reset um7044a
________________________________________________________________________ http://www.union-ic.com rev.04 jul.2012 7/8 um70xxa package information um70xxa: sot23-3 outline drawing dimensions millimeters inches symbol min max min max a 1.050 1.250 0.041 0.049 a1 0.000 0.100 0.000 0.004 a2 1.050 1.150 0.041 0.045 b 0.300 0.500 0.012 0.020 c 0.100 0.200 0.004 0.008 d 2.820 3.020 0.111 0.119 e 1.500 1.700 0.059 0.067 e1 2.650 2.950 0.104 0.116 e 0.950ref 0.037ref e1 1.800 2.000 0.071 0.079 l 0.550ref 0.022ref l1 0.300 0.600 0.012 0.024 0 8 0 8 land pattern notes: 1. compound dimension: 2.921.60; 2. unit: mm; 3. general tolerance 0.05mm unless otherwise specified; 4. the layout is just for reference. tape and reel orientation
________________________________________________________________________ http://www.union-ic.com rev.04 jul.2012 8/8 um70xxa important notice the information in this document has been ca refully reviewed and is believed to be accurate. nonetheless, this document is subjec t to change without notice. union assumes no responsibility for any inaccuracies that may be contained in this document, and makes no commitment to update or to keep current the contained information, or to notify a person or organization of any update. union rese rves the right to make changes, at any time, in order to improve reliability, function or design and to attempt to supply the best product possible. union semiconductor, inc add: 7f, no. 5, bibo road, shanghai 201203 tel: 021-51097928 fax: 021-51026018 website: www.union-ic.com
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