Fairchild Semiconductor MM74HC688MTC, MM74HC688MTCX, MM74HC688WM, MM74HC688SJ, MM74HC688CW Datasheet

September 1983

Revised February 1999

MM74HC688 8-Bit Magnitude Comparator (Equality Detector)

© 1999 Fairchild Semiconductor Corporation DS005018.prf www.fairchildsemi.com

MM74HC688

8-Bit Magnitude Comparator (Equality Detector)

General Description

The MM74HC688 equality detector utilizes advanced sili-

con-gate CMOS technolog y to com pare bit f or bit two 8-bi t

words and indicates wheth er 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 se v-

eral packages and enable comparison of words greater

than 8 bits.

This device is useful in m emory block decoding applica-

tions, where memory bloc k enable signals must be ge ner-

ated from computer address information.

The comparator’s output can driv e 10 low power Schottky

equivalent loads. This comparator is functionally and pin

compatible to the 74L S688. All inputs are protected fr om

damage due to static discharge by diodes to V

CC

and

ground.

Features

■ Typical propagation delay: 20 ns

■ Wide power supply range: 2–6V

■ Low quiescent current: 80 µA (74 Series)

■ Large output current: 4 mA (74 Series)

■ Same as HC521

Ordering Code:

Devices also availab le in Tape and Reel. Specify by appending th e s uffix let t er “X” to the ordering cod e.

Connection Diagram

Pin Assignments for DIP

Top View

Truth Table

Logic Diagram

Order Number Package Number Package Description

MM74HC688WM M20B 20-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300” Wide

MM74HC688SJ M20D 20-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide

MM74HC688MTC MTC20 20-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm Wide

MM74HC688N N20A 20-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300” Wide

Inputs

Data Enable

P,Q

G

P = Q

P = QL L

P > QL H

P < QL H

XHH

www.fairchildsemi.com 2

MM74HC688

Absolute Maximum Ratings(Note 1)

(Note 2)

Recommended Operating

Conditions

Note 1: Absolute Maximum Ratings are those values beyond which dam-

age to the device may occur.

Note 2: Unless otherwise specified all voltages are referenced to ground.

Note 3: Power Dissipation temper ature dera ting — plas tic “N” packa ge: −

12 mW/°C from 65 °C to 85°C.

DC Electrical Characteristics (Note 4)

Note 4: For a power supply of 5V ±1 0% the worst c ase ou tput volta ges (V

OH

, and V

OL

) occur for HC at 4.5V. Thus the 4. 5V valu es shoul d be use d when

designing with this supply. Worst case V

IH

and V

IL

occur at V

CC

= 5.5V and 4.5V res pectively. (The V

IH

value at 5.5V is 3.85V.) The worst case leakage c ur-

rent (I

IN

, I

CC

, and I

OZ

) occur for CMOS at the higher voltage and so th e 6. 0V values should be used.

Supply Voltage (V

CC

) −0.5 to +7.0V

DC Input Voltage (V

IN

) −1.5 to V

CC

+1.5V

DC Output Voltage (V

OUT

) −0.5 to V

CC

+0.5V

Clamp Diode Current (I

IK

, I

OK

) ±20 mA

DC Output Current, per pin (I

OUT

) ±25 mA

DC V

CC

or GND Current, per pin (I

CC

) ±50 mA

Storage Temperature Range (T

STG

) −65°C to +150°C

Power Dissipation (P

D

)

(Note 3) 600 mW

S.O. Package only 500 mW

Lead Temperature (T

L

)

(Soldering 10 seconds) 260°C

Min Max Units

Supply Voltage (V

CC

)26V

DC Input or Output Voltage 0 V

CC

V

(V

IN

, V

OUT

)

Operating Temperature Range (T

A

) −40 +85 °C

Input Rise or Fall Times

(t

r

, t

f

) V

CC

= 2.0V 1000 ns

V

CC

= 4.5V 500 ns

V

CC

= 6.0V 400 ns

Symbol Parameter Conditions

V

CC

T

A

= 25°CT

A

= −40 to 85°CT

A

= −55 to 125°C

Units

Typ Guaranteed Limits

V

IH

Minimum HIGH Level 2.0V 1.5 1.5 1.5 V

Input Voltage 4.5V 3.15 3.15 3.15 V

6.0V 4.2 4.2 4.2 V

V

IL

Maximum LOW Level 2.0V 0.5 0.5 0.5 V

Input Voltage 4.5V 1.35 1.35 1.35 V

6.0V 1.8 1.8 1.8 V

V

OH

Minimum HIGH Level V

IN

= V

IH

or V

IL

Output Voltage |I

OUT

| ≤ 20 µA 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

V

IN

= V

IH

or V

IL

|I

OUT

| ≤ 4.0 mA 4.5V 4.2 3.98 3.84 3.7 V

|I

OUT

| ≤ 5.2 mA 6.0V 5.7 5.48 5.34 5.2 V

V

OL

Maximum LOW Level V

IN

= V

IH

or V

IL

Output Voltage |I

OUT

| ≤ 20 µA 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

V

IN

= V

IH

or V

IL

|I

OUT

| ≤ 4.0 mA 4.5V 0.2 0.26 0.33 0.4 V

|I

OUT

| ≤ 5.2 mA 6.0V 0.2 0.26 0.33 0.4 V

I

IN

Maximum Input V

IN

= V

CC

or GND 6.0V ±0.1 ±1.0 ±1.0 µA

Current

I

CC

Maximum Quiescent V

IN

= V

CC

or GND 6.0V 8.0 80 160 µA

Supply Current I

OUT

= 0 µA