MM74HC688 8-Bit Magnitude Comparator (Equality Detector)
September 1983
Revised May 2005
MM74HC688
8-Bit Magnitude Comparator (Equality Detector)
The comparators output can drive 10 low power Schottky
General Description
equivalent loads. This comparator is functionally and pin
The MM74HC688 equality detector utilizes advanced sili-
compatible to the 74LS688. All inputs are protected from
con-gate CMOS technology to compare bit for bit two 8-bit
damage due to static discharge by diodes to V and
CC
words and indicates whether or not they are equal. The
ground.
P Q output indicates equality when it is LOW. A single
active low enable is provided to facilitate cascading of sev-
Features
eral packages and enable comparison of words greater
than 8 bits.
Typical propagation delay: 20 ns
This device is useful in memory block decoding applica-
Wide power supply range: 26V
tions, where memory block enable signals must be gener-
Low quiescent current: 80 PA (74 Series)
ated from computer address information.
Large output current: 4 mA (74 Series)
Same as HC521
Ordering Code:
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
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 Q
P QL L
P ! QL H
P QL H
XH H
2005 Fairchild Semiconductor Corporation DS005018 www.fairchildsemi.comAbsolute Maximum Ratings(Note 1) Recommended Operating
(Note 2)
Conditions
Supply Voltage (V ) 0.5 to 7.0V
CC Min Max Units
DC Input Voltage (V ) 1.5 to V 1.5V
IN CC Supply Voltage (V)26V
CC
DC Output Voltage (V ) 0.5 to V 0.5V
OUT CC DC Input or Output Voltage 0 V V
CC
Clamp Diode Current (I , I ) r20 mA
IK OK (V , V )
IN OUT
DC Output Current, per pin (I ) r25 mA
OUT Operating Temperature Range (T ) 40 85 qC
A
DC V or GND Current, per pin (I ) r50 mA
CC CC Input Rise or Fall Times
Storage Temperature Range (T ) 65qC to 150qC
STG (t , t ) V 2.0V 1000 ns
r f CC
Power Dissipation (P )
D V 4.5V 500 ns
CC
(Note 3) 600 mW
V 6.0V 400 ns
CC
S.O. Package only 500 mW
Note 1: Absolute Maximum Ratings are those values beyond which dam-
age to the device may occur.
Lead Temperature (T )
L
Note 2: Unless otherwise specified all voltages are referenced to ground.
(Soldering 10 seconds) 260qC
Note 3: Power Dissipation temperature derating plastic N package:
12 mW/qC from 65 qC to 85 qC.
DC Electrical Characteristics (Note 4)
T 25qCT 40 to 85qCT 55 to 125qC
A A A
Symbol Parameter Conditions V Units
CC
Typ Guaranteed Limits
V Minimum HIGH Level 2.0V 1.5 1.5 1.5 V
IH
Input Voltage 4.5V 3.15 3.15 3.15 V
6.0V 4.2 4.2 4.2 V
V Maximum LOW Level 2.0V 0.5 0.5 0.5 V
IL
Input Voltage 4.5V 1.35 1.35 1.35 V
6.0V 1.8 1.8 1.8 V
V Minimum HIGH Level V V or V
OH IN IH IL
Output Voltage |I | d 20 PA 2.0V 2.0 1.9 1.9 1.9 V
OUT
4.5V 4.5 4.4 4.4 4.4 V
6.0V 6.0 5.9 5.9 5.9 V
V V or V
IN IH IL
|I | d 4.0 mA 4.5V 4.2 3.98 3.84 3.7 V
OUT
|I | d 5.2 mA 6.0V 5.7 5.48 5.34 5.2 V
OUT
V Maximum LOW Level V V or V
OL IN IH IL
Output Voltage |I | d 20 PA 2.0V 0 0.1 0.1 0.1 V
OUT
4.5V 0 0.1 0.1 0.1 V
6.0V 0 0.1 0.1 0.1 V
V V or V
IN IH IL
|I | d 4.0 mA 4.5V 0.2 0.26 0.33 0.4 V
OUT
|I | d 5.2 mA 6.0V 0.2 0.26 0.33 0.4 V
OUT
I Maximum Input V V or GND 6.0V r0.1 r1.0 r1.0 PA
IN IN CC
Current
I Maximum Quiescent V V or GND 6.0V 8.0 80 160 PA
CC IN CC
Supply Current I 0 PA
OUT
Note 4: For a power supply of 5V r10% the worst case output voltages (V , and V ) occur for HC at 4.5V. Thus the 4.5V values should be used when
OH OL
designing with this supply. Worst case V and V occur at V 5.5V and 4.5V respectively. (The V value at 5.5V is 3.85V.) The worst case leakage cur-
IH IL CC IH
rent (I , I , and I ) occur for CMOS at the higher voltage and so the 6.0V values should be used.
IN CC OZ
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MM74HC688