INTEGRATED CIRCUITS
DATA SHEET
For a complete data sheet, please also download:
• The IC06 74HC/HCT/HCU/HCMOS Logic Family Specifications • The IC06 74HC/HCT/HCU/HCMOS Logic Package Information • The IC06 74HC/HCT/HCU/HCMOS Logic Package Outlines
74HC/HCT85 4-bit magnitude comparator
Product specification File under Integrated Circuits, IC06 December 1990
Philips Semiconductors
Product specification
4-bit magnitude comparator
FEATURES • Serial or parallel expansion without extra gating • Magnitude comparison of any binary words • Output capability: standard • ICC category: MSI GENERAL DESCRIPTION The 74HC/HCT85 are high-speed Si-gate CMOS devices and are pin compatible with low power Schottky TTL (LSTTL). They are specified in compliance with JEDEC standard no. 7A. The 74HC/HCT85 are 4-bit magnitude comparators that can be expanded to almost any length. They perform comparison of two 4-bit binary, BCD or other monotonic codes and present the three possible magnitude results at the outputs (QA>B, QA=B and QAB, IA=B and IAB = = LOW and IA=B = HIGH. For words greater than 4-bits, units can be cascaded by connecting outputs QAΒ and QA=B to the corresponding inputs of the significant comparator.
TYPICAL SYMBOL tPHL/ tPLH PARAMETER propagation delay An, Bn to QA>B, QAB to QAB IA=B to QA=B CI CPD Notes 1. CPD is used to determine the dynamic power dissipation (PD in µW): PD = CPD × VCC2 × fi + ∑ (CL × VCC2 × fo) where: fi = input frequency in MHz fo = output frequency in MHz ∑ (CL × VCC2 × fo) = sum of outputs CL = output load capacitance in pF VCC = supply voltage in V 2. For HC the condition is VI = GND to VCC For HCT the condition is VI = GND to VCC − 1.5 V ORDERING INFORMATION See “74HC/HCT/HCU/HCMOS Logic Package Information”. input capacitance power dissipation capacitance per package notes 1 and 2 CONDITIONS HC CL = 15 pF; VCC = 5 V 20 18 15 11 3.5 18 22 20 15 15 3.5 20 ns ns ns ns pF pF HCT UNIT
December 1990
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Philips Semiconductors
Product specification
4-bit magnitude comparator
PIN DESCRIPTION PIN NO. 2 3 4 5 6 7 8 9, 11, 14, 1, 10, 12, 13, 15 16 SYMBOL IAB QA>B QA=B QA B expansion input A > B output A = B output A < B output ground (0 V) word B inputs word A inputs positive supply voltage
74HC/HCT85
Fig.1 Pin configuration.
Fig.2 Logic symbol.
Fig.3 IEC logic symbol.
December 1990
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Philips Semiconductors
Product specification
4-bit magnitude comparator
74HC/HCT85
Fig.4 Functional diagram.
APPLICATIONS • Process controllers • Servo-motor control FUNCTION TABLE COMPARING INPUTS A3, B3 A3>B3 A3B2 A2B1 A1B0 A0B X X X X X X X X H L L X H L CASCADING INPUTS IAB H L H L H L H L H L L L L H OUTPUTS QAB or QAB to QAB propagation delay IA=B to QA=B output transition time 63 23 18 58 21 17 50 18 14 39 14 11 19 7 6 max. 195 39 33 175 35 30 140 28 24 120 24 20 75 15 13 −40 to +85 min. max. 245 49 42 220 44 37 175 35 30 150 30 26 95 19 16 −40 to +125 UNIT min. max. 295 59 50 265 53 45 210 42 36 180 36 31 110 22 19 ns
74HC/HCT85
TEST CONDITIONS VCC WAVEFORMS (V) 2.0 4.5 6.0 2.0 4.5 6.0 2.0 4.5 6.0 2.0 4.5 6.0 2.0 4.5 6.0 Fig.6
tPHL/ tPLH
ns
Fig.6
tPHL/ tPLH
ns
Fig.6
tPHL/ tPLH
ns
Fig.6
tTHL/ tTLH
ns
Fig.6
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Philips Semiconductors
Product specification
4-bit magnitude comparator
DC CHARACTERISTICS FOR 74HCT For the DC characteristics see “74HC/HCT/HCU/HCMOS Logic Family Specifications”. Output capability: standard ICC category: MSI Note to HCT types
74HC/HCT85
The value of additional quiescent supply current (∆ICC) for a unit load of 1 is given in the family specifications. To determine ∆ICC per input, multiply this value by the unit load coefficient shown in the table below.
INPUT IAB IA=B An, Bn
UNIT LOAD COEFFICIENT 1.00 1.00 1.50 1.50
AC CHARACTERISTICS FOR 74HCT GND = 0 V; tr = tf = 6 ns; CL = 50 pF Tamb (°C) 74HCT SYMBOL PARAMETER +25 min. typ. tPHL/ tPLH tPHL/ tPLH tPHL/ tPLH propagation delay An, Bn to QA>B or QAB to QAB propagation delay IA=B to QA=B output transition time 26 24 18 max. 44 40 31 −40 to +85 min. max. 55 50 39 −40 to +125 UNIT min. max. 66 60 47 ns ns ns 4.5 4.5 4.5 Fig.6 Fig.6 Fig.6 VCC WAVEFORMS (V) TEST CONDITIONS
tPHL/ tPLH tTHL/ tTLH
18 7
31 15
39 19
47 22
ns ns
4.5 4.5
Fig.6 Fig.6
December 1990
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Philips Semiconductors
Product specification
4-bit magnitude comparator
AC WAVEFORMS
74HC/HCT85
(1) HC : VM = 50%; VI = GND to VCC. HCT: VM = 1.3 V; VI = GND to 3 V.
Fig.6
Waveforms showing the word A inputs (An), word B inputs (Bn) and expansion inputs (In) to the outputs (Qn) propagation delays and the output transition times.
APPLICATION INFORMATION
Fig.7 Series cascading; comparing 12-bit words.
December 1990
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Philips Semiconductors
Product specification
4-bit magnitude comparator
74HC/HCT85
Fig.8 Parallel cascading; comparing 12-bit words.
PACKAGE OUTLINES See “74HC/HCT/HCU/HCMOS Logic Package Outlines”.
December 1990
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