PL138-48 Datasheet, PDF (8/20 Pages) Microchip Technology – 2.5V to 3.3V, Low-Skew, 1:4 Differential PECL Fanout Buffer

PL138-48
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:
AdditivePhaseJitter = OutputPhaseJitter² – InputPhaseJitter²
TABLE 3-1: PL138-48 NOISE CHARACTERISTICS
Parameters
Symbol Min.
Typ.
Max.
—
20
40
—
Additive Phase Jitter t_APJ
—
50
100
50
100
—
50
100
Units
fs
Conditions
V_DD = 3.3V, Frequency = 622.08 MHz
Offset = 12 kHz ~ 20 MHz
V_DD = 3.3V, Frequency = 156.25 MHz
Offset = 12 kHz ~ 20 MHz
V_DD = 3.3V, Frequency = 50 MHz
Offset = 1 kHz ~ 1 MHz
V_DD = 3.3V, Frequency = 25 MHz
Offset = 1 kHz ~ 1 MHz
FIGURE 3-1:
PL138-48 Additive Phase Jitter Plot, 622 MHz.
DS20005543B-page 8
 2016 Microchip Technology Inc.