JKAU: Eng. Sci., Vol 17 No. 1, pp: 25 - 32 (2006A.D. /1427 A.H.) Efficient Design of a Compact Two-Level Multiple-Output Logic Network Ali M. Rushdi and Omar M. Ba-Rukab * Department of Electrical and Computer Engineering, King Abdulaziz University, and * Dept. of Computer Technology, College of Telecom. & Electronics, Jeddah, Saudi Arabia Abstract. This note proposes a minor modification of a recently-developed method that achieves two-level multiple- output logic minimization via the constrained minimization of a single function. The modified method is simpler and more efficient than the original one, but unlike the original method, it does not guarantee exact minimality except for small-size circuits. 1. Introduction A new method for obtaining a two-level collective minimal cover for a set of switching functions } , ... , , { n f f f S 2 1 = has been recently proposed by the authors [1] . This method relies on the introduction of an auxiliary function F whose subfunctions (restrictions) with respect to (n- 1) additional auxiliary variables ) ( y y 1 2 1 - n , ... , , y are certain (possibly repeated) members of S. A particularly constrained minimal cover for F is shown [1] to contain only labeled versions of some paramount prime implicants (PPIs) of S and can be used to construct an exactly minimal multiple-output cover of S. Our method [1] adds an additional (n-1)- valued dimension for the multiple output, in contrast to earlier auxiliary- function methods [2,3] which add an n valued dimension. Hence, the spatial complexity of our method [1] is one half that of these methods. Likewise, this complexity is almost one half that of PPI-based methods [4] . 25