PL138-48

DS20005543B-page 8

 2016 Microchip Technology Inc.

3.0

NOISE CHARACTERISTICS

When a buffer is used to pass a signal, the buffer adds 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 of 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 3-1:

FIGURE 3-1:

PL138-48 Additive Phase Jitter Plot, 622 MHz.

TABLE 3-1:

PL138-48 NOISE CHARACTERISTICS

Parameters

Symbol

Min.

Typ.

Max.

Units Conditions

Additive Phase Jitter

—20

40

fs

Offset = 12 kHz ~ 20 MHz

—50

100

Offset = 12 kHz ~ 20 MHz

—50

100

Offset = 1 kHz ~ 1 MHz

—50

100

Offset = 1 kHz ~ 1 MHz

AdditivePhaseJitter

OutputPhaseJitter

2

InputPhaseJitter

2

–

=