1/9 june 2001 n high speed: t pd = 4.1 ns (typ.) at v cc =5v n low power dissipation: i cc =2 m a (max.) at t a =25 c n compatible with ttl outputs: v ih = 2v (min.), v il = 0.8v (max) n power down protection on inputs & outputs n symmetrical output impedance: |i oh |=i ol = 8 ma (min) n balanced propagation delays: t plh @ t phl n operating voltage range: v cc (opr) = 4.5v to 5.5v n pin and function compatible with 74 series 157 n improved latch-up immunity n low noise: v olp = 0.8v (max.) description the 74vhct157a is an advanced high-speed cmos quad 2-channel multiplexer fabricated with sub-micron silicon gate and double-layer metal wiring c 2 mos technology. it consists of four 2-input digital multiplexer with common select and strobe inputs. it is a non-inverting multiplexer. when the strobe input is held high, selection of data is inhibited and all the outputs become low. the select decoding determines whether the a or b inputs get routed to their corresponding y outputs. power down protection is provided on all inputs and outputs and 0 to 7v can be accepted on inputs with no regard to the supply voltage. this device can be used to interface 5v to 3v since all inputs are equipped with ttl threshold. all inputs and outputs are equipped with protection circuits against static discharge, giving them 2kv esd immunity and transient excess voltage. 74vhct157a quad 2 channel multiplexer pin connection and iec logic symbols order codes package tube t & r sop 74VHCT157AM 74VHCT157AMtr tssop 74vhct157attr tssop sop
74vhct157a 2/9 input equivalent circuit pin description truth table x : don't care logic diagram pin no symbol name and function 1 select common data select inputs 2, 5, 11, 14 1a to 4a data inputs from source a 3, 6, 10, 13 1b to 4b data inputs from source b 4, 7, 9, 12 1y to 4y multiplexer outputs 15 strobe strobe input 8 gnd ground (0v) 16 v cc positive supply voltage inputs output strobe select a b y hxxxl lllxl llhxh lhxll lhxhh
74vhct157a 3/9 absolute maximum ratings absolute maximum ratings are those values beyond which damage to the device may occur. functional operation under these conditions is not implied 1) v cc =0v 2) high or low state recommended operating conditions 1) v cc =0v 2) high or low state 3) vin from 0.8v to 2v symbol parameter value unit v cc supply voltage -0.5 to +7.0 v v i dc input voltage -0.5 to +7.0 v v o dc output voltage (see note 1) -0.5 to +7.0 v v o dc output voltage (see note 2) -0.5 to v cc + 0.5 v i ik dc input diode current -20 ma i ok dc output diode current 20 ma i o dc output current 25 ma i cc or i gnd dc v cc or ground current 50 ma t stg storage temperature -65 to +150 c t l lead temperature (10 sec) 300 c symbol parameter value unit v cc supply voltage 4.5 to 5.5 v v i input voltage 0 to 5.5 v v o output voltage (see note 1) 0 to 5.5 v v o output voltage (see note 2) 0 to v cc v t op operating temperature -55 to 125 c dt/dv input rise and fall time (see note 3) (v cc = 5.0 0.5v) 0 to 20 ns/v
74vhct157a 4/9 dc specifications ac electrical characteristics (input t r =t f = 3ns) (*) voltage range is 5.0v 0.5v capacitive characteristics 1) c pd is defined as the value of the ic's internal equivalent capacitance which is calculated from the operating current consumption without load. (refer to test circuit). average operating current can be obtained by the following equation. i cc(opr) =c pd xv cc xf in +i cc /4 (per channel) symbol parameter test condition value unit v cc (v) t a =25 c -40 to 85 c -55 to 125 c min. typ. max. min. max. min. max. v ih high level input voltage 4.5 to 5.5 222v v il low level input voltage 4.5 to 5.5 0.8 0.8 0.8 v v oh high level output voltage 4.5 i o =-50 m a 4.4 4.5 4.4 4.4 v 4.5 i o =-8 ma 3.94 3.8 3.7 v ol low level output voltage 4.5 i o =50 m a 0.0 0.1 0.1 0.1 v 4.5 i o =8 ma 0.36 0.44 0.55 i i input leakage current 0to 5.5 v i = 5.5v or gnd 0.1 1.0 1.0 m a i cc quiescent supply current 5.5 v i =v cc or gnd 22020 m a i cc additional worst case supply current 5.5 one input at 3.4v, other input at v cc or gnd 1.35 1.5 1.5 ma i opd output leakage current 0 v out = 5.5v 0.5 5.0 5.0 m a symbol parameter test condition value unit v cc (*) (v) c l (pf) t a =25 c -40 to 85 c -55 to 125 c min. typ. max. min. max. min. max. t plh t phl propagation delay time a, b, to y 5.0 15 4.1 6.4 1.0 7.5 1.0 7.5 ns 5.0 50 5.6 8.4 1.0 9.5 1.0 9.5 t plh t phl propagation delay time select to y 5.0 15 5.3 8.1 1.0 9.5 1.0 9.5 ns 5.0 50 6.8 10.1 1.0 11.5 1.0 11.5 t plh t phl propagation delay time strobe to y 5.0 15 5.6 8.6 1.0 10.0 1.0 10.0 ns 5.0 50 7.1 10.6 1.0 12.0 1.0 12.0 symbol parameter test condition value unit t a =25 c -40 to 85 c -55 to 125 c min. typ. max. min. max. min. max. c in input capacitance 6101010pf c pd power dissipation capacitance (note 1) 18 pf
74vhct157a 5/9 dynamic switching characteristics 1) worst case package. 2) max number of outputs defined as (n). data inputs are driven 0v to 3.0v, (n-1) outputs switching and one output at gnd. 3) max number of data inputs (n) switching. (n-1) switching 0v to 3.0v. inputs under test switching: 3.0v to threshold (v ild ), 0v to threshold (v ihd ), f=1mhz. test circuit c l =15/50pf or equivalent (includes jig and probe capacitance) r t =z out of pulse generator (typically 50 w ) symbol parameter test condition value unit v cc (v) t a =25 c -40 to 85 c -55 to 125 c min. typ. max. min. max. min. max. v olp dynamic low voltage quiet output (note 1, 2) 5.0 c l =50pf 0.3 0.8 v v olv -0.8 -0.3 v ihd dynamic high voltage input (note 1, 3) 5.0 2.0 v ild dynamic low voltage input (note 1, 3) 5.0 0.8
74vhct157a 6/9 waveform 1: propagation delays for inverting conditions waveform 2: propagation delays for non-inverting conditions
74vhct157a 7/9 dim. mm. inch min. typ max. min. typ. max. a 1.75 0.068 a1 0.1 0.2 0.003 0.007 a2 1.65 0.064 b 0.35 0.46 0.013 0.018 b1 0.19 0.25 0.007 0.010 c 0.5 0.019 c1 45 (typ.) d 9.8 10 0.385 0.393 e 5.8 6.2 0.228 0.244 e 1.27 0.050 e3 8.89 0.350 f 3.8 4.0 0.149 0.157 g 4.6 5.3 0.181 0.208 l 0.5 1.27 0.019 0.050 m 0.62 0.024 s8 (max.) so-16 mechanical data po13h
74vhct157a 8/9 dim. mm. inch min. typ max. min. typ. max. a 1.2 0.047 a1 0.05 0.15 0.002 0.004 0.006 a2 0.8 1 1.05 0.031 0.039 0.041 b 0.19 0.30 0.007 0.012 c 0.09 0.20 0.004 0.0089 d 4.9 5 5.1 0.193 0.197 0.201 e 6.2 6.4 6.6 0.244 0.252 0.260 e1 4.3 4.4 4.48 0.169 0.173 0.176 e 0.65 bsc 0.0256 bsc k0 8 0 8 l 0.45 0.60 0.75 0.018 0.024 0.030 tssop16 mechanical data c e b a2 a e1 d 1 pin 1 identification a1 l k e 0080338d
74vhct157a information furnished is believed to be accurate and reliable. however, stmicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringe ment of patents or other righ ts of third parties which may result from its use. no license is granted by implication or otherwise under any patent or patent rights of stmicroelectronics. specifications mentioned in this pub lication are subject to change without notice. thi s pub lication supersedes and replaces all information previously supplied. stmicroelectronics prod ucts are not authori zed for use as critical components in life suppo rt devices or systems without express written approval of stmicroelectronics. ? the st logo is a registered trademark of stmicroelectronics ? 2001 stmicroelectronics - printed in italy - all rights reserved stmicroelectronics group of companies australia - brazil - china - finland - france - germany - hong kong - india - italy - japan - malaysia - malta - morocco singapore - spain - sweden - swit zerland - united kingdom ? http://w ww.st.com 9/9
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