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2020 Microchip Technology Inc.

DS20006309B-page 3

PL133-21

2.0

NOISE CHARACTERISTICS

FIGURE 2-1:

PL133-21 Additive Phase Jitter. VDD = 3.3V, CLK = 26 MHz, Integration Range:

12 kHz to 5 MHz, 0.127 ps Typical.

When a buffer is used to pass a signal then the buffer will add a little bit of its own noise. The phase noise on the output

of the buffer will be a little bit more than the phase noise in the input signal. To quantify the noise addition in the buffer

we compare the Phase Jitter numbers from the input and the output. The difference is called Additive Phase Jitter. The

formula for the Additive Phase Jitter is as follows:

EQUATION 2-1:

TABLE 2-1:

NOISE CHARACTERISTICS

Parameter

Symbol

Min.

Typ.

Max.

Units

Conditions

Additive Phase Jitter

—

130

—

fs

VDD = 3.3V, Frequency = 26 MHz

Offset = 12 kHz ~ 5 MHz

—

150

—

VDD = 3.3V, Frequency = 100 MHz

Offset = 12 kHz ~ 20 MHz

-170

-160

-150

-140

-130

-120

-110

-100

-90

-80

-70

10

100

1000

10000

100000

1000000

10000000

Offset Frequency (Hz)

REF Input

PL133-21 Output

Additive Phase Jitter

Output Phase Jitter2 Input Phase Jitter2

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