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
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, B0-b3, Inputs 3Sul' 3LSul
Inputs 1Sul LSul
Outputs 10ul 10Sul 10LSul
Where unit load (ul) understood 40nA -1.6mA l|(_, unit load (Sul) 50/uA -2.0mA llL, 74LS unit load (LSul) 20mA -0.4mA l,L.
CONFIGURATION
LOGIC SYMBOL
LOGIC SYMBOL (IEEE/IEC)
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 arid 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, Ia-b HIGH, Ia<b 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 Ia>b input, Ia<b 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
a3<b3
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
<MSB)B23
-BlO
-b9.
-(LSei
'a>6
'a<b
'a>b
'a.b
'a>b
'a<b
'a-b
'a>b
'a<b
'a-b
<a>B
Figure Comparison 24-bit Words
Table
WORD NUMBER TYPICAL SPEEDS
LENGTH PACKAGES 74LS
Bits 23ns 12ns 23ns
5-25 Bits 40ns 22ns 46ns
25-120 Bits 8-31 63ns 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 +VCc
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 tree-air temperature range unless otherwise noted.)
PARAMETER TEST CONDITIONS1 7485 74LS85 74S85 UNIT
Typ2 Typ2 Typ2
HIGH-level output voltage WIN, MIN, MAX,
LOW-level output voltage MIN, MIN, 0.35
(74LS) 0.25
Input clamp voltage MIN, -1.5 -1.5 -1.2
Input current maximum input voltage 5.5V
7.0V
Other inputs
HIGH-level input current 2.4V
Other inputs
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:
conditions shown MAX, appropriate value specified under recommended operating conditions applicable type.
typical values
3.1Qs tested with V0ut +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, LS85,
ELECTRICAL CHARACTERISTICS 5.0V
74LS
PARAMETER TEST CONDITIONS 15pF, 400H 15pF, 15pF, UNIT
tpLH tpHL Propagation delay input output Waveform logic levels 16.5
tpLH 'PHL Propagation delay input output Waveform logic levels 16.5
tpLH tpHL Propagation delay input output Waveform logic level
tpLH 'PHL Propagation delay input output Waveform logic levels 10.5
tpHL Propagation delay input output Waveform logic level
WAVEFORMS
L'PHcj l-'PLH-j l-'PHL-j |-'PLH*|
VOUT 'OUT
WF07570S 74LS; 1.5V other families. Waveform Waveform Inverting Outputs 74LS; 1.5V other families. Waveform Waveform Non-inverting Outputs
December 1985
This Material
Copyrighted
5-130
Respective
Manufacturer
Signetics Logic Products
Product Specification
Comparators
7485, LS85,
TEST CIRCUITS WAVEFORMS
10%/
lTLH(lrl
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. tjLHi tjHL 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
3.0V 500ns
74LS 3.0V 500ns 15ns
3.0V 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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