7485, LS85, Comparators 4-Bit Magnitude Comparator Product S

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7485, LS85, Comparators 4-Bit Magnitude Comparator Product S

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Signetics
7485, LS85,
Comparators
4-Bit Magnitude Comparator Product Specification
Logic Products
Magnitude comparison binary words
Serial parallel expansion without extra gating
74S85 very high speed comparisons
DESCRIPTION
4-bit magnitude comparator that expanded almost length. compares 4-bit binary, BCD, other monotonic codes presents three possible magnitude results outputs. 4-bit inputs weighted (A0-a3) (B0-B3), where most significant bits.
operation described Function Table, showing possible logic conditions. upper part table describes normal operation under conditions that will occur single device series expansion scheme.
TYPE TYPICAL PROPAGATION DELAY TYPICAL SUPPLY CURRENT (TOTAL)
7485 23ns 55mA
74LS85 23ns 10mA
74S85 12ns 73mA
ORDERING CODE
PACKAGES COMMERCIAL RANGE
Plastic N7485N, N74LS85N, N74S85N
Plastic N74LS85D, N74S85D
NOTE:
information regarding devices processed Military Specifications, Signetics Military Products Data Manual.
INPUT OUTPUT LOADING FAN-OUT TABLE
PINS DESCRIPTION 74LS
A0-A3, Bo-B3> lA_B Inputs 3Sul LSul
Inputs 1Sul 1LSul
Outputs 10ul 10Sul 10LSul
NOTE:
Where unit load (ul) understood -1,6mA l,L, unit load (Sul) 50jjA -2.0mA l!L, 74LS unit load (LSul) 20/jA -0.4mA l|L.
CONFIGURATION
LOGIC SYMBOL
LOGIC SYMBOL (IEEE/IEC)
'A>B
CO04020S
December 1985
5-125
853-0570 81501
This Material Copyrighted Respective Manufacturer
Signetics Logic Products
Product Specification
Comparators 7485, LS85,
upper part table three outputs mutually exclusive. lower part table, outputs reflect feedforward conditions that exist parallel expansion scheme.
expansion inputs least significant positions. When used series expansion, outputs least significant word connected corresponding inputs next higher stage. Stages added this manner length, propagation delay penalty about 15ns added with each additional stage. proper operation expansion inputs least significant word should tied follows: LOW, HIGH, LOW.
parallel expansion scheme shown Figure demonstrates most efficient general these comparators. parallel expansion scheme, expansion inputs used fifth input position except least significant device which must connected serial scheme. expansion inputs used labeling input, input setting LOW. used 5-bit comparator only when outputs used drive inputs another device. parallel technique expanded number bits shown Table
comparing inputs cascading inputs outputs
a0>b0
HIGH voltage level voltage level Don't care
December 1985 5-126
This Material Copyrighted Respective Manufacturer
LOGIC DIAGRAM
FUNCTION TABLE
Signetics Logic Products
Product Specification
Comparators
7485, LS85,
inputs
(MS8IB23
-A,2
-A,0
-a6-
b3-a3
-(lsbi
ea>8
'a<b
'a>6
'a>6
'a<b
Figure Comparison 24-bit Words
Table
WORD LENGTH NUMBER PACKAGES TYPICAL SPEEDS
74LS
Bits 23ns 12ns 23ns
5-25 Bits 40ns 22ns 46ns
25-120 Bits 8-31 34ns 69ns
December 1985 5-127
This Material Copyrighted Respective Manufacturer
Signetics Logic Products
Product Specification
Comparators 7485, LS85,
ABSOLUTE MAXIMUM RATINGS (Over operating free-air temperature range unless otherwise noted.)
PARAMETER 74LS UNIT
Supply voltage
Input voltage -0.5 +5.5 -0.5 +7.0 -0.5 +5.5
Input current
Voltage applied output HIGH output state -0.5 +Vcc -0.5 +VCC -0.5
Operating free-air temperature range
RECOMMENDED OPERATING CONDITIONS
PARAMETER 74LS UNIT
Supply voltage 4.75 5.25 4.75 5.25 4.75 5.25
HIGH-level input voltage
LOW-level input voltage
Input clamp current
HIGH-level output current -400 -400 -1000
LOW-level output current
Operating free-air temperature
December 1985 5-128
This Material Copyrighted Respective Manufacturer
Signetics Logic Products
Product Specification
Comparators 7485, LS85,
ELECTRICAL CHARACTERISTICS (Over recommended operating free-air temperature range unless otherwise noted.)
PARAMETER TEST CONDITIONS1 7485 74LS85 74S85 UNIT
Typ2 Typ2 Typ2
HIGH-level output voltage MIN, MIN, MAX,
LOW-level output voltage 0.35
0.25
Input clamp voltage MIN. -1.5 -1.5 -1.2
Input current maximum input voltage 5.5V
Other inputs
HIGH-level input current 2.4V
Other inputs
2.7V Ia<b.
Other inputs
LOW-level input current 0.4V -1.6 -0.4
Other inputs -4.8 -1.2
0.5V -2.0
Other inputs -6.0
Short-circuit output current3 -100 -100
Supply current4 (total) 10.4
S54S85W only,
NOTES:
1.For conditions shown MAX, appropriate value specified under recommended operating conditions applicable type.
typical values
tested with Vqut +0.5V 0.5V. more than output should shorted time duration short circuit should exceed second.
measured with outputs open, grounded, other inputs 4.5V.
December 1985 5-129
This Material Copyrighted Respective Manufacturer
Signetics Logic Products
Product Specification
Comparators 7485 LS86
ELECTRICAL CHARACTERISTICS
PARAMETER TEST CONDITIONS 74LS
15pF, 400n 15pF, 2ki2 15pF, UNIT
Propagation delay tPLH input output Waveform logic levels 16.5
Propagation delay input output Waveform logic levels 16.5
tpLH Propagation delay tpu, 'A<B input output Waveform logic level
Propagation delay Ia-b input output Waveform logic levels 10.5
tpLH Propagation delay Ia>b la.b input output Waveform logic level
WAVEFORMS
L-'phl-
Vqut
Mpli
1-3V 74LS; 1.5V other families.
Waveform Waveform Inverting Outputs
l-'phl-
"out
l-'plm
1.3V 74LS; 1.5V other families.
Waveform Waveform Non-inverting Outputs
December 1985
This Material Copyrighted Respective Manufacturer
Signetics Logic Products
Product Specification
Comparators
7485, LS85,
TEST CIRCUITS WAVEFORMS
r10% 10%-
Test Circuit Totem-Pole Outputs
definitions
Load resistor Vcc; CHARACTERISTICS value. Load capacitance includes probe capacitance;
CHARACTERISTICS value. Termination resistance should equal Zout
Pulse Generators. Diodes 1N916, 1N3064, equivalent. t-thl Values should less than equal table entries.
1,3V 74LS; 1,5V other families.
Input Pulse Definition
FAMILY INPUT PULSE REQUIREMENTS
Amplitude Rep. Rate Pulse Width *TLH tTHL
3.0V 1MHz 500ns
3.0V 1MHz 500ns 15ns
3.0V 1MHz 500ns 2.5ns 2.5ns
December 1985 5-131
This Material Copyrighted Respective Manufacturer

7485, LS85, Comparators 4-Bit Magnitude Comparator Product S

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