Revised May 2005 MM74HC688 8-Bit Magnitude Comparator (Equality Detector) General Description The MM74HC688 equality detector utilizes advanced silicon-gate CMOS technology to compare bit for bit two 8-bit words and indicates whether or not they are equal. The P Q output indicates equality when it is LOW. A single active low enable is provided to facilitate cascading of several packages and enable comparison of words greater than 8 bits. This device is useful in memory block decoding applications, where memory block enable signals must be generated from computer address information. The comparator’s output can drive 10 low power Schottky equivalent loads. This comparator is functionally and pin compatible to the 74LS688. All inputs are protected from damage due to static discharge by diodes to VCC and ground. Features ■ Typical propagation delay: 20 ns ■ Wide power supply range: 2–6V ■ Low quiescent current: 80 PA (74 Series) ■ Large output current: 4 mA (74 Series) ■ Same as HC521 Ordering Code: Order Number Package Number MM74HC688WM MM74HC688SJ MM74HC688MTC MM74HC688N Package Description M20B 20-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300" Wide M20D 20-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide MTC20 N20A 20-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm Wide 20-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300" Wide Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code. Connection Diagram Logic Diagram Pin Assignments for DIP Top View Truth Table Inputs Data Enable P,Q G P P Q Q L L P!Q L H PQ L H X H H © 2005 Fairchild Semiconductor Corporation DS005018 www.fairchildsemi.com MM74HC688 8-Bit Magnitude Comparator (Equality Detector) September 1983 MM74HC688 Absolute Maximum Ratings(Note 1) Recommended Operating Conditions (Note 2) Supply Voltage (VCC) DC Input Voltage (VIN) DC Output Voltage (VOUT) Clamp Diode Current (IIK, IOK) DC Output Current, per pin (IOUT) DC VCC or GND Current, per pin (ICC) Storage Temperature Range (TSTG) 0.5 to 7.0V 1.5 to VCC 1.5V 0.5 to VCC 0.5V r20 mA r25 mA r50 mA 65qC to 150qC Min Max Supply Voltage (VCC) 2 6 V DC Input or Output Voltage 0 VCC V 40 85 qC (VIN, VOUT ) Operating Temperature Range (TA) Input Rise or Fall Times (tr, tf) VCC 2.0V 1000 ns VCC 4.5V 500 ns VCC 6.0V 400 ns Power Dissipation (PD) (Note 3) 600 mW S.O. Package only 500 mW Note 1: Absolute Maximum Ratings are those values beyond which damage to the device may occur. Lead Temperature (TL) DC Electrical Characteristics Symbol VIH VIL Parameter Conditions TA VCC 25qC Typ TA 40 to 85qC TA 55 to 125qC Guaranteed Limits Units 2.0V 1.5 1.5 1.5 V 4.5V 3.15 3.15 3.15 V 6.0V 4.2 4.2 4.2 V Maximum LOW Level 2.0V 0.5 0.5 0.5 V 4.5V 1.35 1.35 1.35 V 6.0V 1.8 1.8 1.8 V Minimum HIGH Level VIN Output Voltage |IOUT| d 20 PA VIH or VIL 2.0V 2.0 1.9 1.9 1.9 V 4.5V 4.5 4.4 4.4 4.4 V 6.0V 6.0 5.9 5.9 5.9 V |IOUT| d 4.0 mA 4.5V 4.2 3.98 3.84 3.7 V |IOUT| d 5.2 mA 6.0V 5.7 5.48 5.34 5.2 V VIH or VIL Maximum LOW Level VIN Output Voltage |IOUT| d 20 PA VIH or VIL 2.0V 0 0.1 0.1 0.1 V 4.5V 0 0.1 0.1 0.1 V 6.0V 0 0.1 0.1 0.1 V |IOUT| d 4.0 mA 4.5V 0.2 0.26 0.33 0.4 V |IOUT| d 5.2 mA 6.0V 0.2 0.26 0.33 0.4 V VIN VCC or GND 6.0V r0.1 r1.0 r1.0 PA Maximum Quiescent VIN VCC or GND 6.0V 8.0 80 160 PA Supply Current IOUT VIN IIN (Note 4) Input Voltage VIN VOL Note 3: Power Dissipation temperature derating — plastic “N” package: 12 mW/qC from 65qC to 85qC. Minimum HIGH Level Input Voltage VOH Note 2: Unless otherwise specified all voltages are referenced to ground. 260qC (Soldering 10 seconds) Units Maximum Input VIH or VIL Current ICC 0 PA Note 4: For a power supply of 5V r10% the worst case output voltages (VOH, and VOL) occur for HC at 4.5V. Thus the 4.5V values should be used when designing with this supply. Worst case VIH and VIL occur at VCC 5.5V and 4.5V respectively. (The VIH value at 5.5V is 3.85V.) The worst case leakage current (IIN, ICC, and IOZ) occur for CMOS at the higher voltage and so the 6.0V values should be used. www.fairchildsemi.com 2 VCC 5V, TA 25qC, CL Symbol tPHL, tPLH 15 pF, tr tf 6 ns Parameter Conditions Typ Maximum Propagation Guaranteed Limit Units 21 30 ns 14 20 ns Delay, any P or Q to Output tPLH, tPHL Maximum Propagation Delay, Enable to any Output AC Electrical Characteristics VCC 2.0V to 6.0V, CL Symbol tPHL, tPLH tPHL, tPLH tTHL, tTLH CPD 50 pF, tr Parameter tf 6 ns (unless otherwise specified) Conditions TA 25qC VCC Typ TA 40 to 85qC TA 55 to 125qC Guaranteed Limits Units Maximum Propagation 2.0V 60 175 220 263 ns Delay, P or Q to 4.5V 22 35 44 53 ns Output 6.0V 19 30 38 45 ns Maximum Propagation 2.0V 45 120 150 180 ns Delay, Enable to 4.5V 15 24 30 36 ns Output 6.0V 13 20 25 30 ns Maximum Output Rise 2.0V 30 75 95 110 ns and Fall Time 4.5V 8 15 19 22 ns 6.0V 7 13 16 19 Power Dissipation 45 ns pF Capacitance (Note 5) CIN Maximum Input 5 10 10 10 pF Capacitance Note 5: CPD determines the no load dynamic power consumption, PD IS CPD VCC f ICC. CPD VCC2 f ICC VCC, and the no load dynamic current consumption, 3 www.fairchildsemi.com MM74HC688 AC Electrical Characteristics MM74HC688 Physical Dimensions inches (millimeters) unless otherwise noted 20-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300" Wide Package Number M20B www.fairchildsemi.com 4 MM74HC688 Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 20-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide Package Number M20D 5 www.fairchildsemi.com MM74HC688 Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 20-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm Wide Package Number MTC20 www.fairchildsemi.com 6 MM74HC688 8-Bit Magnitude Comparator (Equality Detector) Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 20-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300" Wide Package Number N20A Fairchild does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and Fairchild reserves the right at any time without notice to change said circuitry and specifications. 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