1/10 june 2001 n high speed: t pd = 4.8 ns (typ.) at v cc = 5v n low power dissipation: i cc = 4 m a (max.) at t a =25c 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 257 n improved latch-up immunity n low noise: v olp = 0.8v (max.) description the 74vhct257a is an advanced high-speed cmos quad 2-channel multiplexer (3-state) fabricated with sub-micron silicon gate and double-layer metal wiring c 2 mos technology. it is composed of four independent 2-channel multiplexers with common select and enable input(oe) . the vhct257a is a non-inverting multiplexer. when the enable input is held "high", all outputs become high impedance state. if select input is held "low", "a" data is selected, when select input is "high", "b" data is chosen. 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. 74vhct257a quad 2 channel multiplexer (3-state) pin connection and iec logic symbols order codes package tube t & r sop 74vhct257am 74VHCT257AMTR tssop 74vhct257attr tssop sop
74vhct257a 2/10 input equivalent circuit pin description truth table x : dont care z : high impedance logic diagram this logic diagram has not be used to estimate propagation delays 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 3 state multiplexer outputs 15 oe 3 state output enable inputs (active low) 8 gnd ground (0v) 16 v cc positive supply voltage inputs output oe select a b y hxxxz lllxl llhxh lhxll lhxhh
74vhct257a 3/10 absolute maximum ratings absolute maximum ratings are those values beyond which damage to the device may occur. functional operation under these conditi ons is not implied 1) output in off state 2) high or low state recommended operating conditions 1) output in off state 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
74vhct257a 4/10 dc specifications ac electrical characteristics (input t r = t f = 3ns) (*) voltage range is 5.0v 0.5v symbol parameter test condition value unit v cc (v) t a = 25c -40 to 85c -55 to 125c 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 ioz high impedance output leakage current 5.5 v i = v ih or v il v o = 0v to 5.5v 0.25 2.5 2.5 m a i i input leakage current 0 to 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 44040 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 = 25c -40 to 85c -55 to 125c min. typ. max. min. max. min. max. t plh t phl propagation delay time a, b, to y 5.0 15 4.8 7.0 1.0 8.0 1.0 8.0 ns 5.0 50 5.5 8.0 1.0 9.0 1.0 9.0 t plh t phl propagation delay time select to y 5.0 15 6.0 6.8 1.0 8.0 1.0 8.0 ns 5.0 50 7.0 8.8 1.0 10.0 1.0 10.0 t pzl t pzh output enable time 5.0 15 5.8 6.8 1.0 8.0 1.0 8.0 ns 5.0 50 6.5 8.8 1.0 10.0 1.0 10.0 t plz t phz output disable time 5.0 50 5.7 7.9 1.0 9.0 1.0 9.0 ns
74vhct257a 5/10 capacitive characteristics 1) c pd is defined as the value of the ics 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 x v cc x f in + i cc /4 (per channel) 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. symbol parameter test condition value unit t a = 25c -40 to 85c -55 to 125c min. typ. max. min. max. min. max. c in input capacitance 4101010pf c out output capacitance 6pf c pd power dissipation capacitance (note 1) 23 pf symbol parameter test condition value unit v cc (v) t a = 25c -40 to 85c -55 to 125c min. typ. max. min. max. min. max. v olp dynamic low voltage quiet output (note 1, 2) 5.0 c l = 50 pf 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
74vhct257a 6/10 test circuit c l =15/ 50pf or equivalent (includes jig and probe capacitance) r l = r 1 = 1k w or equivalent r t = z out of pulse generator (typically 50 w ) waveform 1: propagation delays for inverting conditions (f=1mhz; 50% duty cycle) test switch t plh , t phl open t pzl , t plz v cc t pzh , t phz gnd
74vhct257a 7/10 waveform 2: propagation delays for non-inverting conditions (f=1mhz; 50% duty cycle) waveform 3: output enable and disable time (f=1mhz; 50% duty cycle)
74vhct257a 8/10 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
74vhct257a 9/10 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 80 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
74vhct257a 10/10 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 infringement of patents or other rights of third parties which may result f rom its use. no license is granted by implication or otherwise under any patent or patent rights of stmicroelectronics. specificati ons mentioned in this publication are subject to change without notice. this publication supersedes and replaces all information previously supplied. stmicroelectronics products are not authorized for use as critical components in life support 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 - switzerland - united kingdom ? http://www.st.com
|
