1/9 september 2001 n high speed: t pd = 21ns (typ.) at v cc = 4.5v 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 symmetrical output impedance: |i oh | = i ol = 4ma (min) n balanced propagation delays: t plh @ t phl n pin and function compatible with 74 series 688 description the m74hct688 is an high speed cmos 8 bit equality comparator fabricated with silicon gate c 2 mos technology. the m74hct688 compares bit for bit two 8-bit words applied on inputs p0 - p7 and inputs q0 - q7 and indicates whether or not they are equal. a single active low enable is provided to facilitate cascading several packages to enable comparison of words greater than 8 bits. all inputs are equipped with protection circuits against static discharge and transient excess voltage. m74hct688 8 bit equality comparator pin connection and iec logic symbols order codes package tube t & r dip M74HCT688B1R sop m74hct688m1r m74hct688rm13tr tssop m74hct688ttr tssop dip sop
m74hct688 2/9 input and output equivalent circuit pin description truth table x: dont care logic diagram this logic diagram has not be used to estimate propagation delays pin no symbol name and function 1g enable input (active low) 2, 4, 6, 8, 11, 13, 15, 17 p0 to p7 word inputs 3, 5, 7, 9, 12, 14, 16, 18 q0 to q7 word outputs 19 p = q equal to output 10 gnd ground (0v) 20 v cc positive supply voltage inputs output p, q g p = q p = q l l p <> q l h xhh
m74hct688 3/9 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 (*) 500mw at 65 c; derate to 300mw by 10mw/ c from 65 c to 85 c recommended operating conditions dc specifications symbol parameter value unit v cc supply voltage -0.5 to +7 v v i dc input voltage -0.5 to v cc + 0.5 v v o dc output voltage -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 p d power dissipation 500(*) mw 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 v cc v v o output voltage 0 to v cc v t op operating temperature -55 to 125 c t r , t f input rise and fall time (v cc = 4.5 to 5.5v) 0 to 500 ns 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 2.0 2.0 2.0 v 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 =-20 m a 4.4 4.5 4.4 4.4 v i o =-4.0 ma 4.18 4.31 4.13 4.10 v ol low level output voltage 4.5 i o =20 m a 0.0 0.1 0.1 0.1 v i o =4.0 ma 0.17 0.26 0.33 0.40 i i input leakage current 5.5 v i = v cc or gnd 0.1 1 1 m a i cc quiescent supply current 5.5 v i = v cc or gnd 44080 m a d i cc additional worst case supply current 5.5 per input pin v i = 0.5v or v i = 2.4v other inputs at v cc or gnd i o = 0 2.0 2.9 3.0 ma
m74hct688 4/9 ac electrical characteristics (c l = 50 pf, input t r = t f = 6ns) 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 test circuit c l = 50pf/150pf 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 = 25c -40 to 85c -55 to 125c min. typ. max. min. max. min. max. t tlh t thl output transition time 4.5 8151922ns t plh t phl propagation delay time (pn, qn - p=q ) 4.5 21 32 40 48 ns t plh t phl propagation delay time (g - p=q ) 4.5 15 23 29 35 ns 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. c in input capacitance 5101010pf c pd power dissipation capacitance (note 1) 32 pf
m74hct688 5/9 waveform : propagation delay time (f=1mhz; 50% duty cycle)
m74hct688 6/9 dim. mm. inch min. typ max. min. typ. max. a1 0.254 0.010 b 1.39 1.65 0.055 0.065 b 0.45 0.018 b1 0.25 0.010 d 25.4 1.000 e 8.5 0.335 e 2.54 0.100 e3 22.86 0.900 f 7.1 0.280 i 3.93 0.155 l 3.3 0.130 z 1.34 0.053 plastic dip-20 (0.25) mechanical data p001j
m74hct688 7/9 dim. mm. inch min. typ max. min. typ. max. a 2.65 0.104 a1 0.1 0.2 0.004 0.008 a2 2.45 0.096 b 0.35 0.49 0.014 0.019 b1 0.23 0.32 0.009 0.012 c 0.5 0.020 c1 45 (typ.) d 12.60 13.00 0.496 0.512 e 10.00 10.65 0.393 0.419 e 1.27 0.050 e3 11.43 0.450 f 7.40 7.60 0.291 0.300 l 0.50 1.27 0.020 0.050 m 0.75 0.029 s8 (max.) so-20 mechanical data po13l
m74hct688 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 6.4 6.5 6.6 0.252 0.256 0.260 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 tssop20 mechanical data c e b a2 a e1 d 1 pin 1 identification a1 l k e 0087225c
m74hct688 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 ? 2000 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 9/9
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