7.11 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 7-11 shows the setup used to measure charge injection from

Drain (D) to Source (Sx).

V

DD

V

DD

OUTPUT

C

L

SELx

S1A

D1

GND

0.1

F

V

OUT

Output

V

S

Q

C = CL ×

V

OUT

V

OUT

V

SEL

V

D

S1B

N.C.

0 V

V

DD

VSEL

OUTPUT

C

L

S2A

D2

V

OUT

S2B

N.C.

Figure 7-11. Charge-Injection Measurement Setup

7.12 Bandwidth

Bandwidth is defined as the range of frequencies that are attenuated by less than 3 dB when the input is applied

to the source pin (Sx) of an on-channel, and the output is measured at the drain pin (D) of the device. Figure

7-12 shows the setup used to measure bandwidth.

GND

NETWORK

ANALYZER

V

OUT

S

D

50

V

SIG

R

L

50

V

S

V

DD

0.1 µF

SxA / SxB

R

L

50

Figure 7-12. Bandwidth Measurement Setup

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TMUX2889

SCDS464 – JUNE 2023

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