Improved Target Impedance for Power Distribution Network Design With Power Traces Based on Rigorous Transient Analysis in a Handheld Device

The concept of target impedance can be significantly improved, based on the rigorous closed-form expressions for transient supply voltage ripple excited by an integrated circuit (IC) switching current, for the power distribution network (PDN) with power traces that is commonly used in handheld devices. A systematic procedure for developing the target impedance is formulated, which is then applied to the PDN design of a handheld product. From measurements of transient IC switching currents, PDN impedance, and supply voltage ripple, it is shown that the proposed target impedance successfully correlates the PDN impedance in the frequency domain with the transient supply voltage ripple in the time domain.