54283/DM74283 4-Bit Binary Full Adder (with Fast Carry) General Description The ’283 high speed 4-bit binary full adders with internal carry lookahead accept two 4-bit binary words (A0–A3, B0 – B3) and a Carry input (C0). They generate the binary Sum outputs (S0–S3) and the Carry output (C4) from the most significant bit. They operate with either active HIGH or active LOW operands (positive or negative logic). Connection Diagram Dual-In-Line Package TL/F/9786 – 1 Order Number 54283DMQB, 54283FMQB or DM74283N See NS Package Number J16A, N16E or W16A Pin Names A0–A3 B0–B3 C0 S0–S3 C4 C1995 National Semiconductor Corporation TL/F/9786 Description A Operand Inputs B Operand Inputs Carry Input Sum Outputs Carry Output RRD-B30M115/Printed in U. S. A. 54283/DM74283 4-Bit Binary Full Adder (with Fast Carry) June 1989 Absolute Maximum Ratings (Note) Note: 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. If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/Distributors for availability and specifications. Supply Voltage Input Voltage Operating Free Air Temperature Range 54 DM74 7V b 55§ C to a 125§ C 0§ C to a 70§ C Storage Temperature Range b 65§ C to a 150§ C 5.5V Recommended Operating Conditions Symbol 54283 Parameter VCC Supply Voltage VIH High Level Input Voltage VIL Low Level Input Voltage IOH High Level Output Current IOL Low Level Output Current TA Free Air Operating Temperature DM74283 Units Min Nom Max Min Nom Max 4.5 5 5.5 4.75 5 5.25 2 2 V 0.8 0.8 V b 0.4 b 0.4 mA 16 b 55 V 125 0 16 mA 70 §C Max Units b 1.5 V Electrical Characteristics Over recommended operating free air temperature range (unless otherwise noted) Symbol VI Parameter Conditions Input Clamp Voltage VCC e Min, II e b12 mA VOH High Level Output Voltage VCC e Min, IOH e Max VIL e Max VOL Low Level Output Voltage VCC e Min, IOL e Max VIH e Min II Input Current @ Max Input Voltage VCC e Max, VI e 5.5V IIH High Level Input Current IIL IOS IOS ICCH Min 2.4 Typ (Note 1) 3.4 0.4 V 1 mA VCC e Max, VI e 2.4V 40 mA Low Level Input Current VCC e Max, VI e 0.4V b 1.6 mA Short Circuit Output Current at Sn VCC e Max (Note 2) 54 b 20 b 55 DM74 b 20 b 55 Short Circuit Output Current at C4 VCC e Max (Note 2) 54 b 20 b 70 DM74 b 18 b 70 Supply Current with Outputs High VCC e Max 54 99 DM74 110 Note 1: All typicals are at VCC e 5V, TA e 25§ C. Note 2: Not more than one output should be shorted at a time. 2 0.2 V mA mA mA Switching Characteristics VCC e a 5.0V, TA e a 25§ C (See Section 1 for waveforms and load configurations) Symbol CL e 15 pF, RL e 400X Parameter Min Units Max tPLH tPHL Propagation Delay C0 or Sn 21 21 ns tPLH tPHL Propagation Delay An or Bn to Sn 24 24 ns tPLH tPHL Propagation Delay C0 to C4 14 16 ns tPLH tPHL Propagation Delay An or Bn to C4 14 16 ns Functional Description The ’283 adds two 4-bit binary words (A plus B) plus the incoming carry C0. The binary sum appears on the Sum (S0 – S3) and outgoing carry (C4 outputs. The binary weight of the various inputs and outputs is indicated by the subscript numbers, representing powers of two. 20 (A0 a B0 a C0) a 21 (A1 a B1) a 22 (A2 a B2) a 23 (A3 a B3) e S0 a 2S1 a 4S2 a 8S3 a 16C4 Where ( a ) e plus Interchanging inputs of equal weight does not affect the operation. Thus C0, A0, B0 can be arbitrarily assigned to pins 5, 6 and 7. Due to the symmetry of the binary add function, the ’283 can be used either with all inputs and outputs active HIGH (positive logic) or with all inputs and outputs active LOW (negative logic). Note that if C0 is not used it must be tied LOW for active HIGH logic or tied HIGH for active LOW logic. Example: Due to pin limitations, the intermediate carries of the ’283 are not brought out for use as inputs or outputs. However, other means can be used to effectively insert a carry into, or bring a carry out from, an intermediate stage. Figure a shows a way of making a 3-bit adder. Tying the operand inputs of the fourth adder (A3, B3) LOW makes S3 dependent ony on, and equal to, the carry from the third adder. Using somewhat the same principle,Figure b shows a way of dividing the ’283 into a 2-bit and a 1-bit adder. The third stage adder (A2, B2, S2) is used merely as a means of getting a carry (C10) signal into the fourth stage (via A2 and B2) and bringing out the carry from the second stage on S2. Note that as long as A2 and B2 are the same, whether HIGH or LOW, they do not infuence S2. Similarly, when A2 and B2 are the same the carry into the third stage does not influence they carry out of the third stage. Figure c shows a method of implementing a 5-input encoder, where the inputs are equally weighted. The outputs S0, S1 and S2 present a binary number equal to the number of inputs I1 – I5 that are true. Figure d shows one method of implementing a 5-input majority gate. When three or more of the inputs I1 – I5 are true, the output M5 is true. C0 A0 A1 A2 A3 B0 B1 B2 B3 S0 S1 S2 S3 C4 Logic Levels L L H L H H L L H H H L L H Active HIGH 0 0 1 0 1 1 0 0 1 1 1 0 0 1 Active LOW 1 1 0 1 0 0 1 1 0 0 0 1 1 0 Active HIGH: 0 a 10 a 9 e 3 a 16 Active LOW: 1 a 5 a 6 e 12 a 0 TL/F/9786 – 3 FIGURE a. 3-Bit Adder TL/F/9786 – 4 FIGURE b. 2-Bit and 1-Bit Adders 3 Functional Description (Continued) TL/F/9786 – 5 FIGURE c. 5-Input Encoder TL/F/9786 – 6 FIGURE d. 5-Input Majority Gate Logic Symbol TL/F/9786 – 2 VCC e Pin 16 GND e Pin 8 Logic Diagram TL/F/9786 – 7 4 Physical Dimensions inches (millimeters) 16-Lead Ceramic Dual-In-Line Package (J) Order Number 54283DMQB NS Package Number J16A 16-Lead Molded Dual-In-Line Package (N) Order Number DM74283N NS Package Number N16E 5 54283/DM74283 4-Bit Binary Full Adder (with Fast Carry) Physical Dimensions inches (millimeters) (Continued) 16-Lead Ceramic Flat Package (W) Order Number 54283FMQB NS Package Number W16A LIFE SUPPORT POLICY NATIONAL’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 NATIONAL SEMICONDUCTOR CORPORATION. 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