DM74LS85 4-Bit Magnitude Comparators General Description These 4-bit magnitude comparators perform comparison of straight binary or BCD codes. Three fully-decoded decisions about two, 4-bit words (A, B) are made and are externally available at three outputs. These devices are fully expandable to any number of bits without external gates. Words of greater length may be compared by connecting comparators in cascade. The A > B, A < B, and A = B outputs of a stage handling less-significant bits are connected to the corresponding inputs of the next stage handling more-significant bits. The stage handling the least-significant bits must have a high-level voltage applied to the A = B input. The cascading path is implemented with only a two-gate-level delay to reduce overall comparison times for long words. Features n Typical power dissipation 52 mW n Typical delay (4-bit words) 24 ns n Alternate Military/Aerospace device (54LS85) is available. 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Connection Diagram Dual-In-Line Package DS006379-1 Order Number 54LS85DMQB, 54LS85FMQB, 54LS85LMQB, DM54LS85J, DM54LS85W, DM74LS85M or DM74LS85N See Package Number E20A, J16A, M16A, N16E or W16A (c) 1998 Fairchild Semiconductor Corporation DS006379 www.fairchildsemi.com DM74LS85 4-Bit Magnitude Comparators March 1998 Function Table Comparing Cascading Inputs Inputs Outputs A3, B3 A2, B2 A1, B1 A0, B0 A>B A<B A=B A>B A<B A=B A3 > B3 X X X X X X H L L A3 < B3 A3 = B3 A3 = B3 X X X X X X L H L A2 > B2 X X X X X H L L A2 < B2 A2 = B2 A2 = B2 X X X X X L H L A3 = B3 A3 = B3 A1 > B1 X X X X H L L X X X L H L A2 = B2 A2 = B2 A2 = B2 A1 < B1 A1 = B1 A1 = B1 X A3 = B3 A3 = B3 A3 = B3 A0 > B0 X X X H L L X X L H L H L L H L L A3 = B3 A3 = B3 A3 = B3 A2 = B2 A2 = B2 A2 = B2 A0 < B0 A0 = B0 A0 = B0 X A1 = B1 A1 = B1 L H L L H L L H L L H X X H L L H A2 = B2 A2 = B2 A0 = B0 A0 = B0 A0 = B0 L A3 = B3 A3 = B3 A1 = B1 A1 = B1 A1 = B1 H H L L L L A1 = B1 A0 = B0 L L L H H L H = High Level, L = Low Level, X = Don't Care www.fairchildsemi.com 2 Absolute Maximum Ratings (Note 1) Supply Voltage Input Voltage Operating Free Air Temperature Range DM54LS and 54LS DM74LS Storage Temperature Range 7V 7V -55C to +125C 0C to +70C -65C to +150C Recommended Operating Conditions Symbol Parameter DM54LS85 DM74LS85 Units Min Nom Max Min Nom Max 4.5 5 5.5 4.75 5 5.25 VCC Supply Voltage VIH High Level Input Voltage VIL Low Level Input Voltage 0.7 0.8 V IOH High Level Output Current -0.4 -0.4 mA IOL Low Level Output Current 8 mA TA Free Air Operating Temperature 70 C 2 2 V 4 -55 125 V 0 Note 1: The "Absolute Maximum Ratings" are those values beyond which the safety of the device cannot be guaranteed. The device should not be operated at these limits. The parametric values defined in the "Electrical Characteristics" table are not guaranteed at the absolute maximum ratings. The "Recommended Operating Conditions" table will define the conditions for actual device operation. Electrical Characteristics over recommended operating free air temperature range (unless otherwise noted) Symbol Parameter Conditions Min Typ Max Units (Note 2) VI Input Clamp Voltage VOH High Level Output Voltage VOL Low Level Output Voltage Input Current @ Max II Input Voltage IIH High Level Input Current IIL Low Level Input Current IOS ICC VCC = Min, II = -18 mA VCC = Min, IOH = Max VIL = Max, VIH = Min -1.5 DM54 2.5 DM74 2.7 3.4 3.4 VCC = Min, IOL = Max VIL = Max, VIH = Min IOL = 4 mA, VCC = Min VCC = Max VI = 7V A<B 0.1 A>B 0.1 Others 0.3 VCC = Max VI = 2.7V VCC = Max VI = 0.4V DM54 0.25 DM74 0.35 0.4 0.5 DM74 0.25 0.4 A<B 20 A>B 20 Others 60 A<B -0.4 A>B -0.4 Others -1.2 Short Circuit VCC = Max DM54 -20 -100 Output Current (Note 3) VCC = Max (Note 4) DM74 -20 -100 Supply Current V V 10 20 V mA A mA mA mA Note 2: All typicals are at VCC = 5V, TA = 25C. Note 3: Not more than one output should be shorted at a time, and the duration should not exceed one second. Note 4: ICC is measured with all outputs open, A = B grounded and all other inputs at 4.5V. 3 www.fairchildsemi.com Switching Characteristics at VCC = 5V and TA = 25C Symbol Parameter From To Number of Input Output Gate Levels RL = 2 k CL = 50 pF CL = 15 pF Min tPLH tPHL tPLH Units Max Propagation Delay Time Any A or B A < B, 3 36 42 Data Input A>B A=B 4 40 40 ns Propagation Delay Time Any A or B A < B, 3 30 40 High-to-Low Level Output Data Input A>B A=B 4 30 40 A<B or A = B A>B 1 22 26 ns Propagation Delay Time Propagation Delay Time High-to-Low Level Output tPLH Min Low-to-High Level Output Low-to-High Level Output tPHL Max Propagation Delay Time ns A<B A>B 1 17 26 ns or A = B A =B A=B 2 20 25 ns A=B A=B 2 17 26 ns A>B or A = B A<B 1 22 26 ns A>B or A = B A<B 1 17 26 ns Low-to-High Level Output tPHL Propagation Delay Time High-to-Low Level Output tPLH Propagation Delay Time Low-to-High Level Output tPHL Propagation Delay Time High-to-Low Level Output www.fairchildsemi.com 4 Logic Diagram DS006379-2 5 www.fairchildsemi.com Physical Dimensions inches (millimeters) unless otherwise noted Chip Carrier Package (E) Order Number 54LS85LMQB Package Number E20A 16-Lead Ceramic Dual-In-Line Package (J) Order Number 54LS85DMQB or DM54LS85J Package Number J16A www.fairchildsemi.com 6 Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 16-Lead Small Outline Molded Package (M) Order Number DM74LS85M Package Number M16A 16-Lead Molded Dual-In-Line Package (N) Order Number DM74LS85N Package Number N16E 7 www.fairchildsemi.com DM74LS85 4-Bit Magnitude Comparators Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 16-Lead Ceramic Flat Package (W) Order Number 54LS85FMQB or DM54LS85W Package Number W16A LIFE SUPPORT POLICY FAIRCHILD'S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR CORPORATION. As used herein: 2. A critical component in any component of a life support 1. Life support devices or systems are devices or sysdevice or system whose failure to perform can be reatems which, (a) are intended for surgical implant into sonably expected to cause the failure of the life support the body, or (b) support or sustain life, and (c) whose device or system, or to affect its safety or effectiveness. failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user. Fairchild Semiconductor Corporation Americas Customer Response Center Tel: 1-888-522-5372 www.fairchildsemi.com Fairchild Semiconductor Europe Fax: +49 (0) 1 80-530 85 86 Email: europe.support@nsc.com Deutsch Tel: +49 (0) 8 141-35-0 English Tel: +44 (0) 1 793-85-68-56 Italy Tel: +39 (0) 2 57 5631 Fairchild Semiconductor Hong Kong Ltd. 13th Floor, Straight Block, Ocean Centre, 5 Canton Rd. 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