Load Regulation ΔVout/ΔIout and Output Impedance Zout
October 6, 2023
Masashi Nogawa, Sr. Member of Technical Staff, Qorvo
Published on Microwave Journal.com
In Masashi’s latest installment of his ongoing blog series exploring Power Supply Ripple Rejection (PSRR), he takes a brief detour from PSRR investigations to shift his attention to another essential factor in voltage regulation: output impedance (ZOUT).
In this installment of our blog series about Power Supply Ripple Rejection, we’ll take a break and shift our focus from PSRR to output impedance ZOUT.
Before the 21st century, most voltage regulator datasheets started their electrical characteristics (EC) tables with two key parameters:
Line Regulation
Load Regulation
For example, the LM317 datasheet of the early days [1] started its electrical characteristic table with the values as seen in Table 1:

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