GND

SX

Dx

Audio Precision

VOUT

RL

VDD

VDD

0.1 µF

VS

40

Ω

Figure 14-9. THD + N Measurement Setup

14.10 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 100mVPP. 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 14-10. AC PSRR Measurement Setup

14.11 Charge Injection

Any mismatch in capacitance results in a charge injected into the drain or source during the falling or rising edge

of the gate signal. The amount of charge injected into the source or drain of the device is known as charge

injection, and is denoted by the symbol QC. Figure 14-11 shows the setup used to measure charge injection from

Drain (D) to Source (Sx).

TMUX4821, TMUX4819

SCDS487A – OCTOBER 2025 – REVISED DECEMBER 2025

www.ti.com

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