MC54/74F182 CARRY LOOKAHEAD GENERATOR The MC54/74F182 is a high-speed carry lookahead generator. It is generally used with the F181, F381 or 29F01 4-bit arithmetic logic unit to provide highspeed lookahead over word lengths of more than four bits. • Provides Lookahead Carries Across a Group of Four ALUs • Multi-level Lookahead High-speed Arithmetic Operation Over Long Word Lengths CARRY LOOKAHEAD GENERATOR FAST SCHOTTKY TTL CONNECTION DIAGRAM DIP (TOP VIEW) VCC P2 G2 Cn 16 15 14 13 Cn + x Cn + y 12 11 G Cn + z 10 9 J SUFFIX CERAMIC CASE 620-09 16 1 1 2 3 4 5 6 7 8 G1 P1 G0 P0 G3 P3 P GND N SUFFIX PLASTIC CASE 648-08 16 1 D SUFFIX SOIC CASE 751B-03 16 1 LOGIC DIAGRAM Cn G0 P0 G1 P1 G2 P2 ORDERING INFORMATION MC54FXXXJ MC74FXXXN MC74FXXXD G3 P3 Ceramic Plastic SOIC LOGIC SYMBOL 13 Cn Cn + x Cn + y Cn + z G P FAST AND LS TTL DATA 4-97 P0 G0 4 P1 G1 2 3 12 Cn + x 11 Cn + y 9 Cn + z P2 G2 15 14 6 5 P P3 G3 G 7 10 1 VCC = PIN 16 GND = PIN 8 MC54/74F182 FUNCTION TABLE Inputs G1 P1 Outputs Cn G0 P0 G2 P2 G3 P3 Cn+x X H H L L H X L X L X H H X L H Cn+y X X X H H L X H H H X L L H X H X L X X X L X H Cn+z G X L X X L H H X L X L H X X X X X H H L X X X H H H X L X H H H X H X L L H X H X H X L X X X X X L X H X X X L X X L H X L X X L X L H H X L X L X L H X X X X X H H H X X X H H H X H X H H H X H X H H H X H X H X H X X X X X L X L X X X L X X L L X L X X L X L L L X L X L X L L P H X X X H X H X X H X X H X H X X X H H L L L L L H = HIGH Voltage Level L = LOW Voltage Level X = Don’t Care GUARANTEED OPERATING RANGES Symbol Parameter VCC Supply Voltage TA Operating Ambient Temperature Range Min Typ Max Unit 54,74 4.5 5.0 5.5 V 54 –55 25 125 °C 74 0 25 70 IOH Output Current — High 54, 74 –1.0 mA IOL Output Current — Low 54, 74 20 mA FAST AND LS TTL DATA 4-98 MC54/74F182 DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE (unless otherwise specified) Limits Symbol Parameter VIH Input HIGH Voltage VIL Input LOW Voltage VIK Input Clamp Diode Voltage VOH Output HIGH Voltage VOL Output LOW Voltage IIH Input HIGH Current IIL Min Typ Max Unit 2.0 54, 74 2.5 74 2.7 V Guaranteed Input HIGH Voltage 0.8 V Guaranteed Input LOW Voltage –1.2 V IIN = –18 mA VCC = MIN V IOH = –1.0 mA VCC = 4.50 V 3.4 3.4 0.35 V IOH = –1.0 mA VCC = 4.75 V 0.5 V IOL = 20 mA VCC = MIN 20 µA VIN = 2.7 V VCC = MAX 100 µA VIN = 7.0 V VCC = MAX mA VIN = 0.5 V VCC = MAX –150 mA VOUT = 0 V VCC = MAX Cn Input –1.2 P3 Input –2.4 Input LOW P2 Input –3.6 Current G3, P0, P1 Inputs –4.8 G0, G2 Inputs –8.4 G1 Input –9.6 –60 Test Conditions IOS Output Short Circuit Current (Note 2) ICCH Power Supply Current (All Outputs HIGH) 18.4 28 mA P3, G3 = 4.5 V All Other Inputs = GND VCC = MAX ICCL Power Supply Current (All Outputs LOW) 23.5 36 mA G0, G1, G2 = 4.5 V All Other Inputs = GND VCC = MAX NOTES: 1. For conditions shown as MIN or MAX, use the appropriate value specified under guaranteed operating ranges. 2. No more than one output should be shorted at a time, nor for more than 1 second. AC CHARACTERISTICS Symbol Parameter 54/74F 54F 74F TA = +25°C TA = –55°C to +125°C TA = 0°C to +70°C VCC = +5.0 V VCC = 5.0 V ± 10% VCC = 5.0V ± 10% CL = 50 pF CL = 50 pF CL = 50 pF Min Typ Max Min Max Min Max tPLH Propagation Delay 3.0 6.6 8.5 3.0 10.5 3.0 9.5 tPHL Cn to Cn + x, Cn + y, Cn + z 3.0 6.8 9.0 3.0 11 3.0 10 tPLH Propagation Delay 2.5 6.2 8.0 2.5 10.7 2.5 9.0 tPHL P0, P1, or P2 to Cn + x, Cn + y, Cn + z 1.5 3.7 5.0 1.5 6.5 1.5 6.0 tPLH Propagation Delay 2.5 6.5 8.5 2.5 10.5 2.5 9.5 tPHL G0, G1, or G2 to Cn + x, Cn + y, Cn + z 1.5 3.9 5.2 1.5 6.5 1.5 6.0 Unit ns FAST AND LS TTL DATA 4-99 ns ns MC54/74F182 AC CHARACTERISTICS (Continued) Symbol Parameter 54/74F 54F 74F TA = +25°C TA = –55°C to +125°C TA = 0°C to +70°C VCC = +5.0 V VCC = 5.0 V ± 10% VCC = 5.0V ± 10% CL = 50 pF CL = 50 pF CL = 50 pF Min Typ Max Min Max Min Max tPLH Propagation Delay 2.0 7.9 10 2.0 12.5 2.0 11 tPHL P1, P2, or P3 to G 2.0 6.0 8.0 2.0 9.5 2.0 9.0 tPLH Propagation Delay 2.0 8.3 10.5 2.0 12.5 2.0 11.5 tPHL Gn to G 1.5 5.7 7.5 1.5 9.5 1.5 8.5 tPLH Propagation Delay 2.5 5.7 7.5 2.5 11 2.5 8.5 tPHL Pn to P 2.5 4.1 5.5 2.5 7.5 2.5 6.5 Unit ns ns ns FUNCTIONAL DESCRIPTION The F182 carry lookahead generator accepts up to four pairs of active-LOW Carry Propagate (P0-P3) and carry Generate (G0-G3) signals and an active-HIGH Carry input (Cn) and provides anticipated active-HIGH carries (Cn + x, Cn + y, Cn + z) across four groups of binary adders. The F182 also has active-LOW Carry Propagate (P) and Carry Generate (G) outputs which may be used for further levels of lookahead. The logic equations provided at the output are: Cn + x = G0 + P0Cn Cn + y = G1 + P1G0 + P1P0Cn Cn + z = G2 + P2G1 + P2P1G0 + P2P1P0Cn Cn G = G3 + P3G2 + P3P2G1 + P3P2P1G0 P = P3P2P1P0 Also, the F182 can be used with binary ALUs in an activeLOW or active-HIGH input operand mode. The connections (Figure 1) to and from the ALU to the carry lookahead generator are identical in both cases. Carries are rippled between lookahead blocks. The critical speed path follows the circled numbers. There are several possible arrangements for the carry interconnects, but all achieve about the same speed. A 28-bit ALU is formed by dropping the last F181 or F381. Cn ALU** G P ALU** G P A, B 1 Cn Cn + 4 ALU** G P Cn C16 Cn Cn + 4 ALU** G P ALU** G P 5 Cn Cn Cn + 4 ALU** ALU** G P 2 CIN Cn Cn + 4 ALU** F P0 G0 P1 G1 P2G2 P3 G3 Cn F182 G Cn + x Cn + y Cn + zP P0 G0 P1 G1 P2 G2 P3 G3 Cn F182 G Cn + x Cn + y Cn + z P 3 4 ** ALUs may be either F181, F381, or 2901A. Figure 1. 32-Bit ALU with Ripple Carry Between 16-Bit Lookahead ALUs FAST AND LS TTL DATA 4-100 6 COUT (C32)