Area Analysis III : Low Power Design Technology

Basic Assumption

(1) Technology : 0.35um CMOS process
(2) Operating Voltage : 2.5 V (Vt=0.5V) 2.0 V (Vt=0.4V) 1.5 V (Vt=0.3V) 1.0 V (Vt=0.2V)
(3) Operating Temperature : 25 C
(4) Circuit : Double Pass-Transistor Logic
(5) 6 subcycles : 1 main cycle is divided by 4 subcycles
(6) 16 bit Multiplier : Wallace Tree + 32bit CLA Adder
(7) No Architectural Change but Change for Circuit and Process Technology


Area Estimation Method

(1) The Area calculation is based on the paper, Carl Lemonds, "A High Throughput 16 by 16 Bit Multiplier for DSP Cores", IEEE International Symposium on Circuits and Systems, 1996. p479.
(2) Transformation of Area Calculation in Table III of the paper, Carl Lemonds

Channel Width

Dual-Rail Domino Logic

Double Pass Transistor Logic

16bit Multiplier

111.064 mm

65.447 mm

Combinational Logic per 1 transistor

1.832 um

1.080 um

Wallace Tree Compressor per 1 transistor

5.217 um

3.074 um

Register per 1 transistor

7.462 um

4.397 um

16bit Carry Look Ahead Adder

8.760 mm

5.162 mm

32bit Carry Look Ahead Adder

22.379 mm

13.187 mm

48bit Carry Look Ahead Adder

38.736 mm

22.826 mm

64bit Carry Look Ahead Adder

57.170 mm

33.689 mm

96bit Carry Look Ahead Adder

98.957 mm

58.313 mm

128bit Carry Look Ahead Adder

146.052 mm

86.065 um

[ TABLE 23 ]


(3) Area Table 24 : Variable Circuitry

Channel Width

Natural Ratio
with Dual-Rail Domino Logic

Enhanced Natural Ratio
with Dual-Rail Domino Logic

Enhanced Natural Ratio
with Double Pass Transistor Logic

Sail Boat Allocation

104.03 mm

104.03 mm

61.30 mm

16 bit Multiplier

444.26 mm

N/A

N/A

32 bit Wallace Tree

N/A

130.55 mm

76.93 mm

32 bit CLA Adder

N/A

22.38 mm

13.19 mm

48 bit Wallace Tree

61.64 mm

124.83 mm

73.559 mm

48 bit CLA Adder

154.94 mm

N/A

N/A

64 bit CLA Adder

N/A

114.34 mm

67.38 mm

32 bit FP Converter

41.77 mm

20.89 mm

12.31 mm

96 bit Wallace Tree

30.54 mm

61.08 mm

35.99 mm

96 bit CLA Adder

98.96 mm

N/A

N/A

128 bit CLA Adder

N/A

146.05 mm

86.06 mm

96 bit FP Converter

26.68 mm

26.68 mm

15.72 mm

Output Registers

23.40 mm

23.40 mm

13.79 mm

Total Channel Width

986.22 mm

774.23 mm

456.23 mm

relative Area

100.00

78.50

46.26

[ TABLE 24 ]