7.9 THD + Noise

The total harmonic distortion (THD) of a signal is a measurement of the harmonic distortion, and is defined as

the ratio of the sum of the powers of all harmonic components to the power of the fundamental frequency at the

mux output. The on-resistance of the device varies with the amplitude of the input signal and results in distortion

when the drain pin is connected to a low-impedance load. Total harmonic distortion plus noise is denoted as

THD + N.

GND

SX

Dx

Audio Precision

VOUT

RL

VDD

VDD

0.1 µF

VS

40

Ω

Figure 7-9. THD + N Measurement Setup

7.10 Power Supply Rejection Ratio (PSRR)

PSRR measures the ability of a device to prevent noise and spurious signals that appear on the supply voltage

pin from coupling to the output of the switch. The DC voltage on the device supply is modulated by a sine wave

of 100 mVPP. The ratio of the amplitude of signal on the output to the amplitude of the modulated signal is the

AC PSRR.

620 mVPP

RL

Network Analyzer

VOUT

VDD

DC Bias

Injector

VIN

CL

VBIAS

GND

Sx

Dx

VDD

0.1 µF

With and Without

Capacitor

Other SxA/

SxB/Dx pins

50

Ω

50

Ω

50

Ω

Figure 7-10. AC PSRR Measurement Setup

TMUX2889

SCDS464 – JUNE 2023

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