SN54AS882A, SN74AS882A 32-BIT LOOK-AHEAD CARRY GENERATORS SDAS235 – D2661, DECEMBER 1982 – REVISED NOVEMBER 1985 • SN54AS882A . . . JT PACKAGE SN74AS882A . . . DW OR NT PACKAGE Directly Compatible With ’AS181B, ’AS1181, ’AS881B, and ’AS1881 ALUs Package Options Include Plastic Small Outline Packages, Both Plastic and Ceramic Chip Carriers, and Standard Plastic and Ceramic 300-mil DIPs Capable of Anticipating the Carry Across a Group of Eight 4-Bit Binary Adders Cascadable to Perform Look-Ahead Across n-Bit Adders Typical Carry Time, Cn to Any Cn+i, is Less Than 6 ns Dependable Texas Instruments Quality and Reliability • • • • • (TOP VIEW) Cn G0 P0 G1 P1 1 24 2 23 3 22 4 21 5 20 Cn + 8 G2 P2 G3 P3 Cn – 16 GND 6 19 7 18 8 17 9 16 10 15 11 14 12 13 VCC NC Cn + 32 P7 G7 P6 G6 Cn + 24 P5 G5 P4 G4 description SN54AS882A . . . FK PACKAGE SN74AS882A . . . DW OR NT PACKAGE The ’AS882A is a high-speed look-ahead carry generator capable of anticipating the carry across a group of eight 4-bit adders permitting the designer to implement look-ahead for a 32-bit ALU with a single package or, by cascading ’AS882As, full look-ahead is possible across n-bit adders. P0 G0 Cn NC VCC NC C n + 32 (TOP VIEW) The SN54AS882A is characterized for operation over the full military temperature range of – 55°C to 125°C. The SN74AS882A is characterized for operation from 0°C to 70°C. Cn+8 = G1 + P1G0+P1P0Cn Cn+16 = G3 + P3G2 + P3P2G1 + P3P2P1G0 + P3P2P1P0Cn Cn+24 = G5 + P5G4 + P5P4G3 + P5P4P3G2 + P5P4P3P2G1 + P5P4P3P2P1G0 + P5P4P3P2P1P0Cn Cn+32 = 3 2 1 28 27 26 5 6 24 Cn + 8 NC G2 P2 G3 7 23 8 22 9 21 10 20 25 11 19 12 13 14 15 16 17 18 P7 G7 P6 NC G6 Cn + 24 P5 P3 C n + 16 GND NC G4 P4 G5 ’AS882A LOGIC EQUATIONS 4 G1 P1 NC – No internal connection G7 + P7G6 + P7P6G5 + P7P6P5G4 + P7P6P5P4G3 + P7P6P5P4P3G2 + P7P6P5P4P3P2G1 + P7P6P5P4P3P2P1G0 + P7P6P5P4P3P2P1P0Cn Copyright 1985, Texas Instruments Incorporated PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 1 SN54AS882A, SN74AS882A 32-BIT LOOK-AHEAD CARRY GENERATORS SDAS235 – D2661, DECEMBER 1982 – REVISED NOVEMBER 1985 logic symbol† CPG Cn P0 GO P1 G1 P2 G2 P3 G3 P4 G4 P5 G5 P6 G6 P7 G7 1 C1 3 CP0 2 CG0 5 CP1 4 8 7 10 9 CG1 CP2 CO1 CG2 CP3 CO3 6 11 Cn+8 Cn+16 CG3 14 13 16 15 19 18 21 20 CP4 CG4 CO5 CP5 CO7 17 22 Cn+24 Cn+32 CG5 CP6 CG6 CP7 CG7 † This symbol is in accordance with ANSI/IEEE Std 91-1984 and IEC Publication 617-12. Pin numbers shown are for DW, JT, and NT packages. 2 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 SN54AS882A, SN74AS882A 32-BIT LOOK-AHEAD CARRY GENERATORS SDAS235 – D2661, DECEMBER 1982 – REVISED NOVEMBER 1985 FUNCTION TABLE FOR Cn + 32 OUTPUT INPUTS OUTPUT G7 G6 G5 G4 G3 G2 G1 G0 P7 P6 P5 P4 P3 P2 P1 P0 Cn L X X X X X X X X X X X X X X X X Cn + 32 H X L X X X X X X L X X X X X X X X H X X L X X X X X L L X X X X X X X H X X X L X X X X L L L X X X X X X H X X X X L X X X L L L L X X X X X H X X X X X L X X L L L L L X X X X H X X X X X X L X L L L L L L X X X H X X X X X X X L L L L L L L L X X H X X X X X X X X L L L L L L L L H H All other combinations L FUNCTION TABLE FOR Cn+24 OUTPUT INPUTS OUTPUT G5 G4 G3 G2 G1 G0 P5 P4 P3 P2 P1 P0 Cn Cn + 24 L X X X X X X X X X X X X H X L X X X X L X X X X X X H X X L X X X L L X X X X X H X X X L X X L L L X X X X H X X X X L X L L L L X X X H X X X X X L L L L L L X X H X X X X X X L L L L L L H H All other combinations L Function Tables FOR Cn + 16 OUTPUT INPUTS G3 G2 G1 G0 P3 P2 P1 P0 L X X X X X L X X X X X L X X X X X L X X L L L L X X L L L X X X L L X X X X L FOR Cn + 8 OUTPUT INPUTS OUTPUT Cn Cn + 16 H X H X H X H X H H L G1 G0 P1 P0 Cn L X X X L X X L L X X L X X H OUTPUT Cn + 16 H H H L All other combinations All other combinations Any inputs not shown in a given table are irrelevant with respect to that output. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 3 SN54AS882A, SN74AS882A 32-BIT LOOK-AHEAD CARRY GENERATORS SDAS235 – D2661, DECEMBER 1982 – REVISED NOVEMBER 1985 logic diagram (positive logic) P7 P6 P5 P4 21 19 16 14 22 P3 P2 P1 P0 G7 G6 G5 G4 G3 G2 G1 G0 10 8 5 3 20 18 15 13 17 9 4 2 6 1 Pin numbers shown are for DW, JT, and NT packages. 4 Cn + 24 7 11 Cn Cn + 32 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 Cn + 16 Cn + 8 SN54AS882A, SN74AS882A 32-BIT LOOK-AHEAD CARRY GENERATORS SDAS235 – D2661, DECEMBER 1982 – REVISED NOVEMBER 1985 absolute maximum ratings over operating free-air temperature range (unless otherwise noted) Supply voltage, VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 V Input voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 V Operating free-air temperature range: SN54AS882A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 55°C to 125°C SN74AS882A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0°C to 70°C Storage temperature range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 65°C to 150°C recommended operating conditions SN54AS882A SN74AS882A MIN NOM MAX MIN NOM MAX 4.5 5 5.5 4.5 5 5.5 UNIT VCC VIH Supply voltage VIL IOH Low-level input voltage 0.8 0.8 V High-level output current –2 –2 mA IOL TA Low-level output current 20 20 mA 70 °C High-level input voltage 2 Operating free-air temperature – 55 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 2 125 0 V V 5 SN54AS882A, SN74AS882A 32-BIT LOOK-AHEAD CARRY GENERATORS SDAS235 – D2661, DECEMBER 1982 – REVISED NOVEMBER 1985 electrical characteristics over recommended operating free-air temperature range (unless otherwise noted) PARAMETER TEST CONDITIONS VIK VOH VCC = 4.5 V, VCC = 4.5 V to 5.5 V, II = – 18 mA IOH = – 2 mA VOL VCC = 4.5 V, IOL = 20 mA II SN54AS882A TYP† MAX MIN – 1.2 VCC – 2 0.3 0.5 0.5 0.4 0.4 G0, G6 0.8 0.8 G1, G2, G4 1.2 1.2 G3, G5 VCC = 5.5 V, VI = 7 V 1.5 1.5 G7 0.9 0.9 P2, P3 0.3 0.3 P4, P5 0.2 0.2 P6, P7 0.1 0.1 Cn, P 0, P1 80 80 160 160 240 240 300 300 G3, G5 VCC = 5.5 V, VI = 2.7 V G7 180 180 P2, P3 60 60 P4, P5 40 40 P6, P7 20 20 Cn, P 0, P1 –2 –2 G0, G6 –4 –4 G1, G2, G4 –6 –6 – 7.5 – 7.5 G7 – 4.5 – 4.5 P2, P3 – 1.5 – 1.5 P4, P5 –1 –1 P6, P7 – 0.5 – 0.5 G3, G5 VCC = 5.5 V, VI = 0.4 V UNIT V V 0.3 Cn, P 0, P1 G1, G2, G4 IIL – 1.2 VCC – 2 G0, G6 IIH SN74AS882A TYP† MAX MIN V mA µA mA IO‡ VCC = 5.5 V, VO = 2.25 V – 30 – 130 – 30 – 30 mA ICC VCC = 5.5 V 44 70 44 70 mA † All typical values are at VCC = 5 V, TA = 25°C. ‡ The output conditions have been chosen to produce a current that closely approximates one half of the true short-circuit output current, IOS. 6 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 SN54AS882A, SN74AS882A 32-BIT LOOK-AHEAD CARRY GENERATORS SDAS235 – D2661, DECEMBER 1982 – REVISED NOVEMBER 1985 switching characteristics (see Note 1) PARAMETER FROM (INPUT) VCC = 4.5 V to 5.5 V, CL = 50 pF, pF RL = 500 Ω, TA = MIN to t MAX TO (OUTPUT) SN54AS882A tPLH tPHL Cn Any output tPLH tPHL P or G Cn + 8 tPLH tPHL P or G Cn + 16 tPLH tPHL P or G Cn + 24 tPLH tPHL P or G Cn + 32 UNIT SN74AS882A MIN MAX MIN 2 10 2 MAX 9 3 15 3 14 2 8 2 7 2 8 2 7 2 8 2 7 2 8 2 7 2 8 2 7 2 11 2 10 1.5 9 2 8 2 13 2 12 ns NOTE 1: Load circuits and voltage waveforms are shown in Section 1. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 7 SN54AS882A, SN74AS882A 32-BIT LOOK-AHEAD CARRY GENERATORS SDAS235 – D2661, DECEMBER 1982 – REVISED NOVEMBER 1985 TYPICAL APPLICATION DATA The application given in Figure 1 illustrates how the ’AS882A can implement look-ahead carry for a 32-bit ALU (in this case, the popular ’AS881A) with a single package. Typical carry times shown are derived using the standard Advanced Schottky load circuit. A B A B A B A B A B A B A B A B LSB MSB ’AS881A ’AS881A 6 ns Cn 6 ns Cn–4 Cn Cn–4 6 ns ’AS881A F Cn ’AS881A G0 P1 6 ns Cn–4 Cn Cn–4 6 ns 6 ns F F F G1 Cn + 8 6 ns Cn–4 Cn Cn ’AS881A F F P0 Cn–4 Cn ’AS881A P2 G2 P3 G3 Cn+16 ’AS882A Cn P4 G4 P5 G5 6 ns Cn–4 Cn Cn–4 ’AS881A ’AS881A F F Cn + 24 P6 G6 P7 G7 6 ns Cn + 32 7 ns Figure 1 Likewise, Figure 2 illustrates the same 32-bit ALU using two ’AS882s. This shows the worst-case delay from LSB to MSB to be 19 ns as opposed to 25 ns in Figure 1. LSB A B 4 A 4 B 4 A 4 4 B A 4 B 4 A B 4 4 6 ns ’AS881A A 4 ’AS881A Cn Cn Cn 6 ns ’AS881A F F P0 Cn G0 B Cn 4 Cn P2 G2 F P3 Cn Cn G3 6 ns F F Cn + 16 P4 G4 P5 G5 F Cn + 24 P6 G6 6 ns H P0 G0 Cn P1 G1 Cn + 8 P2 G2 P3 G3 Cn + 16 P4 G4 P5 6 ns ’AS882A 7 ns Cn Figure 2 8 P7 G7 Cn + 32 ’AS882A L 4 ’AS881A 6 ns F B MSB A 4 ’AS881A ’AS881A F P1 G1 A ’AS881A ’AS881A 6 ns B 4 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 G5 Cn + 24 P6 G6 P7 G7 Cn + 32 IMPORTANT NOTICE Texas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue any product or service without notice, and advise customers to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability. 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