? semiconductor components industries, llc, 2000 june, 2000 rev. 1 1 publication order number: and8018/d
! prepared by: fred zlotnick, strategic marketing jess diaz, market development standard logic business unit introduction onegate logic devices have been in use for several years, and are nothing more than singlegate derivatives of their multigate cousins. initial offerings were pioneered in japan, to help solve particular problems the design community had encountered. earlier, traditional ics were packaged in 14 and 16 pin dualinline packages (dips), and the goal of the ic manufacturer was to get as much functionality as possible into a singlepackage device. double, triple, quadruple, and quintuple versions of simple logic functions became the norm. the enormously successful 7400ttl/ls logic family of standard bipolar logic ic's became the industry standard for nearly 20 years. ceramic, and later plastic, dip packages became a staple item for logic designers. new, smalloutlineintegratedcircuit (soic) packages began to replace dips as packaging technologies evolved. as cmos process technologies emerged and began to gain popularity, the 4000 series cmos family also followed industry trends. the 4000 series, was not only a low power family, but was also low speed. improvements in cmos technology accelerated process development efforts. the resulting products were faster than older bipolar families, and have become standards within the design community. these newer product families tended to be offered only in soic and smaller packages. the result of all the improvements in cmos technology is that the older bipolar families are now rarely used, except for legacy designs. families such as vhc now offer lower power, and higher speed and drive capabilities than lsttl, at the same or lower cost. the japanese electronics industry is responsible for the majority of the world's consumer electronics designs. one trend in this area has been to get as much function into as small a space as possible, while conserving power. owing to the huge number of units consumed, japanese designers rely on techniques different from that of the rest of the world. to turn new designs quickly, japanese circuit designers created an infrastructure to support rapid design of moderate sized gate arrays, as well as application specific standard products (assp). previously designed gate arrays or assps often needed one bit of buffering, logic, or switching in order to make the circuit usable in a new system design. often there was not enough room to add an additional logic element on the chip and still keep the board size small. the designer was faced with having to redesign the entire chip or to add additional ic components to the board layout to accomplish the required task. a solution to this dilemma was to use onegate designs, initially offered in the sot23, 5pin package, and later in the even smaller sot353 (sc88a). the latter package takes up only 4.2 mm 2 of board space, and less than the area of a tssop20 pin device. onegate products, now fabricated in a .6 m advanced highspeed cmos technology, are very fast, with < 4 nsecs gate delays, and enough drive (8 ma) to support most typical applications. the package is so small, that it fits ainlineo with the trace that it is mounted on. the onegate device is performing only one function at a time. because onegates can be mounted right where they are needed, additional direct benefits to the design are lower aground bounceo effects, smaller number of decoupling component requirements, shorter signal routing lines, and a significant reduction in overall board space. onegate products are beginning to be universally recognized for the value they bring to a design. the design may be a consumer oriented portable product, or a larger computing system such as a workstation. the benefits of improved routing, reduced crosstalk effects, cleaner system signals, and elimination of previously required signal acleanup componentso, are recognized as extremely important to overall system performance, and the use of onegate devices is expected to increase dramatically in the future. http://onsemi.com application note
and8018/d http://onsemi.com 2 typical application cases: example #1 problem: interface a 3.0 volt logic level serial input to a 5.0 volt older board. solution: the 1gt50 provides an interface with no inversion board 1gt50 +5 +5 3.03.3 voh signal discussion: this product is a new function in the industry standard family of onegate products. the 1gt50 operates at 5.0 volts and interfaces seamlessly with 3.0 volt logic levels. no resistors or other additional components are necessary. the devi ce occupies minimum board space and contributes almost no loading (<10 pf). it also provides up 8 ma of drive with minimum noise and ground bounce and only a small signal delay ( 4 ns, depending upon load). example #2 problem: a phase locked loop for a motor driver needs a fast attack time with a long steady state time constant. solution: the 1gt66 or 1g66 (standard industry functions) onegate analog switches. t 1 = rc 1 t 2 = r(c 1 + c 2 ) r c1 c2 lm741 v ref vco ctrl 1g66 f1(ref) phase detector out + discussion: designers are familiar with this function in multigate families. either of these two onegate devices, the 1gt66 or 1g66 (depending on system requirements), allows the designer to specify two time constants. the first time constant is selected for fast attack with perhaps 15% overshoot. the second time constant delivers maximum stability and minimum ripple. the analog switch takes up almost no room on the board and only requires one resistor and two capacitors, as well. when the analog switch is turned aon,o it selects the time constant equal to: t = 2p (c 1 +c 2 ). the longer time constant is effective a few nanoseconds after being switched aono. example #3 problem: how to switch a low power 3.3 volt device aono from a ttl level source. solution: use a 1g66 onegate with v dd connected to the supply voltage of 3.3 volts as a highside switch. device 1g66/1gt66 3.3 discussion: the control pin on the industry standard 1g66 is overvoltage tolerant and may be driven by a 5.0 volt logic driver. the switch will offer only 15 ohms of resistance, resulting in a drop of 0.15 volts with a 10 ma load. this function can turn on a local oscillator, rf stage, small audio output, etc. this low cost switch provides an interface between the 5.0 volt porti on of the system and highside switching. the onegate device occupies only 4.2 mm 2 of board space and requires no external resistors or capacitors.
and8018/d http://onsemi.com 3 example #4 problem: how to make a lowcost/area crystalceramic resonator oscillator solution: the industry standard onegate device, the 1gu04 unbuffered inverter. 10 m u04 cc crystal or resonator up to 25mhz vcc discussion: the 1gu04 makes a perfect oscillator for any fundamental mode crystal. a 10 meg ohm resistor placed from output to input puts the inverter in a classa state. the crystal manufacturer should determine the capacitor value. the oscillator should function up to the maximum value of a fundamental crystal (~25 mhz). the designer can use an overtone crystal to achieve higher frequencies. the designer should follow recommendations of the crystal manufacturer. if buffering is required, any of the vhc onegates or multigate buffers or inverters will perform admirably. example #5 problem: how to create a dual gain audio amplifier with either 0 db gain or +6 db gain. solution: the use of an operational amplifier with selectable feedback resistance provides constant input and output impedance. use a single gate analog switch to select/deselect resistors and provide either unity gain or +6 db. 12 k 24 k 24 k lm741 0, +6 db 1g66 ctrl + vref
and8018/d http://onsemi.com 4 example #6 problem: for many years, programmable array logic (pal's) were used to perform complex logic operations on multiple signals. in the wireless/handheld world, pal's consume too much power. an additional problem arises if the designer needs a complex set of a combinationalo logic. solution: depending on the number of terms needed, open drain single gate devices can provide an excellent solution. open drain gates allow the outputs to be a wiredor'edo together so that the or function is not only free, but is very low power, uses up very little space, and adds practically zero delay into the signal path. the following is an illustration of a complex funct ion: out = (a0 x a1) + (a2 x a3) + (a4 + a5) using three open drain onegate devices (09, 01, and 03), wireor the outputs. to attempt to accomplish this function with a pal would be overkill in both power and board space. using multigate logic would require four devices and >50 mm 2 of board space. the use of open drain devices provides a perfect solution, consuming only 13mm 2 of board space. signal propagation delays would be <7ns, with minimum power consumption (determined by the value of r). a0 out = (a0*a1) + (a2*a3) + (a4*a5) out 09 r v cc 01 a1 a2 a3 a4 a5 on semiconductor and are trademarks of semiconductor components industries, llc (scillc). scillc reserves the right to make changes without further notice to any products herein. scillc makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does scillc assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. atypicalo parameters which may be provided in scill c data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. all operating parameters, including atypicalso must be validated for each customer application by customer's technical experts. scillc does not convey any license under its patent r ights nor the rights of others. scillc products are not designed, intended, or authorized for use as components in systems intended for surgical implant into t he body, or other applications intended to support or sustain life, or for any other application in which the failure of the scillc product could create a sit uation where personal injury or death may occur. should buyer purchase or use scillc products for any such unintended or unauthorized application, buyer shall indemnify and hold scillc and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that scillc was negligent regarding the design or manufacture of the part. scillc is an equal opportunity/affirmative action employer. publication ordering information central/south america: spanish phone : 3033087143 (monfri 8:00am to 5:00pm mst) email : onlitspanish@hibbertco.com asia/pacific : ldc for on semiconductor asia support phone : 3036752121 (tuefri 9:00am to 1:00pm, hong kong time) toll free from hong kong & singapore: 00180044223781 email : onlitasia@hibbertco.com japan : on semiconductor, japan customer focus center 4321 nishigotanda, shinagawaku, tokyo, japan 1410031 phone : 81357402745 email : r14525@onsemi.com on semiconductor website : http://onsemi.com for additional information, please contact your local sales representative. and8018/d sensefet is a trademark of semiconductor components industries, llc. north america literature fulfillment : literature distribution center for on semiconductor p.o. box 5163, denver, colorado 80217 usa phone : 3036752175 or 8003443860 toll free usa/canada fax : 3036752176 or 8003443867 toll free usa/canada email : onlit@hibbertco.com fax response line: 3036752167 or 8003443810 toll free usa/canada n. american technical support : 8002829855 toll free usa/canada europe: ldc for on semiconductor european support german phone : (+1) 3033087140 (mf 1:00pm to 5:00pm munich time) email : onlitgerman@hibbertco.com french phone : (+1) 3033087141 (mf 1:00pm to 5:00pm toulouse time) email : onlitfrench@hibbertco.com english phone : (+1) 3033087142 (mf 12:00pm to 5:00pm uk time) email : onlit@hibbertco.com european tollfree access*: 0080044223781 *available from germany, france, italy, england, ireland
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