MM54HCT688/MM74HCT688 8-Bit Magnitude Comparator (Equality Detector) General Description This equality detector utilizes advanced silicon-gate CMOS technology to compare bit for bit two 8-bit words and indicate whether or not they are equal. The P e 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 combines the low power consumption of CMOS, but inputs are compatible with TTL logic levels, and the output can drive 10 low power Schottky equivalent loads. MM54HCT/MM74HCT devices are intended to interface between TTL and NMOS components and standard CMOS devices. These parts are also plug in replacements for LSTTL devices and can be used to reduce power consumption in existing designs. All inputs are protected from damage due to static discharge by diodes to VCC and ground. Features Y Y Y Y Y TTL input compatible Typical propagation delay: 20 ns Low quiescent current: 80 mA maximum (74HCT Series) Large output current: 4 mA Same as HCT521 Logic Diagrams TL/F/5371 – 2 C1995 National Semiconductor Corporation TL/F/5371 RRD-B30M105/Printed in U. S. A. MM54HCT688/MM74HCT688 8-Bit Magnitude Comparator (Equality Detector) February 1988 Absolute Maximum Ratings (Notes 1 & 2) Operating Conditions If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/Distributors for availability and specifications. Supply Voltage (VCC) 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) Power Dissipation (PD) (Note 3) S.O. Package only Lead Temperature (TL) b 1.5 to VCC a 1.5V g 20 mA Max 5.5 0 VCC Units V V b 40 b 55 a 85 a 125 §C §C 500 ns Input Rise or Fall Times (tr, tf) g 25 mA g 50 mA b 65§ C to a 150§ C 600 mW 500 mW 260§ C DC Electrical Characteristics Parameter Operating Temp. Range (TA) MM74HCT688 MM54HCT688 b 0.5 to VCC a 0.5V (Soldering 10 seconds) Symbol DC Input or Output Voltage (VIN, VOUT) b 0.5 to a 7.0V Min 4.5 (VCC e 5V g 10% unless otherwise specified) TA e 25§ C Conditions 74HCT TA eb40 to 85§ C Typ 54HCT TA eb55 to 125§ C Units Guaranteed Limits VIH Minimum High Level Input Voltage 2.0 2.0 2.0 V VIL Maximum Low Level Input Voltage 0.8 0.8 0.8 V VOH Minimum High Level Output Voltage VIN e 0.8V or 2.0V lIOUTl e 20 mA lIOUTl e 4.0 mA, VCC e 4.5V lIOUTl e 4.8 mA, VCC e 5.5V VCC 4.2 5.7 VCCb0.1 3.98 4.98 VCCb0.1 3.84 4.84 VCCb0.1 3.7 4.7 V V V Maximum Low Level Voltage VIN e V0.8V or 2.0V lIOUTl e 20 mA lIOUTl e 4.0 mA, VCC e 4.5V lIOUTl e 4.8 mA, VCC e 5.5V 0 0.2 0.2 0.1 0.26 0.26 0.1 0.33 0.33 0.1 0.4 0.4 V V V IIN Maximum Input Current VIN e VCC or GND g 0.1 g 1.0 g 1.0 mA ICC Maximum Quiescent Supply Current VIN e VCC or GND IOUT e 0 mA 8.0 80 160 mA VIN e 2.4V or 0.5V (Note 4) 0.3 0.4 0.5 mA VOL Note 1: Absolute Maximum Ratings are those values beyond which damage to the device may occur. Note 2: Unless otherwise specified all voltages are referenced to ground. Note 3: Power Dissipation temperature derating Ð plastic ‘‘N’’ package: b 12 mW/§ C from 65§ C to 85§ C; ceramic ‘‘J’’ package: b 12 mW/§ C from 100§ C to 125§ C. Note 4: Measured per pin. All other inputs held at VCC or ground. 2 AC Electrical Characteristics VCC e 5V, TA e 25§ C, CL e 15 pF, tr e tf e 6 ns (unless otherwise specified) Symbol Parameter Conditions Typ Guaranteed Limit Units tPHL Maximum Propagation Delay - P or Q to Output 19 30 ns tPLH Maximum Propagation Delay - P or Q to Output 13 22 ns tPHL Maximum Propagation Delay - Enable to Output 13 20 ns tPHL Maximum Propagation Delay - Enable to Output 10 18 ns AC Electrical Characteristics VCC e 5V g 10%, CL e 50 pF, tr e tf e 6 ns (unless otherwise specified) Symbol Parameter Conditions TA e 25§ C 74HCT TA eb40 to 85§ C Typ 54HCT TA eb55 to 125§ C Units Guaranteed Limits tPHL Maximum Propagation Delay - P or Q to Output 23 35 44 53 ns tPLH Maximum Propagation Delay - P or Q to Output 16 24 30 36 ns tPHL Maximum Propagation Delay - Enable to Output 16 24 30 36 ns tPLH Maximum Propagation Delay - Enable to Output 11 20 25 30 ns tTHL, tTLH Maximum Output Rise and Fall Time 8 15 19 22 ns CPD Power Dissipation Capacitance (Note 5) 45 CIN Maximum Input Capacitance 5 pF 10 10 10 pF Note 5: CPD determines the no load dynamic power consumption, PD e CPD VCC2 f a ICC VCC, and the no load dynamic current consumption, IS e CPD VCC a ICC. Connection Diagram Truth Table Dual-In-Line Package Inputs Data P, Q PeQ PlQ PkQ X TL/F/5371 – 1 Top View Order Number MM54HCT688 or MM74HCT688 3 Enable G PeQ L L L H L H H H MM54HCT688/MM74HCT688 8-Bit Magnitude Comparator (Equality Detector) Physical Dimensions inches (millimeters) Order Number MM54HCT688J or MM74HCT688J NS Package J20A LIFE SUPPORT POLICY Order Number MM74HCT688N NS Package N20A NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and whose failure to perform, when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user. National Semiconductor Corporation 1111 West Bardin Road Arlington, TX 76017 Tel: 1(800) 272-9959 Fax: 1(800) 737-7018 2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. National Semiconductor Europe Fax: (a49) 0-180-530 85 86 Email: cnjwge @ tevm2.nsc.com Deutsch Tel: (a49) 0-180-530 85 85 English Tel: (a49) 0-180-532 78 32 Fran3ais Tel: (a49) 0-180-532 93 58 Italiano Tel: (a49) 0-180-534 16 80 National Semiconductor Hong Kong Ltd. 13th Floor, Straight Block, Ocean Centre, 5 Canton Rd. Tsimshatsui, Kowloon Hong Kong Tel: (852) 2737-1600 Fax: (852) 2736-9960 National Semiconductor Japan Ltd. Tel: 81-043-299-2309 Fax: 81-043-299-2408 National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.