M908-02 Datasheet Rev 0.4
Revised 30Jul2004
M908-02
VCSO BASED CLOCK GENERATOR
Prelimina r y Inf o r m ation
GENERAL DESCRIPTION
The M908-02 is a PLL (Phase Locked Loop) based
clock generator that uses an
internal VCSO (Voltage Controlled
SAW Oscillator) to produce a very
low jitter output clock. From the
M908-02-155.5200
, an output clock
frequency of 155.52MHz is provided
from eight LVPECL clock output
pairs. (Other frequencies are available; consult factory.)
The accuracy of the output frequency is assured by the
internal PLL that phase-locks the internal VCSO to the
reference input frequency (19.44MHz for the
M908-02-155.5200
). The input reference can either be an
external crystal, utilizing the internal crystal oscillator,
or a stable external clock source such as a packaged
crystal oscillator.
FEATURES
◆ Output clock frequency range 75MHz to 175MHz
(Consult factory for frequency availability)
◆ Eight identical LVPECL output pairs
◆ Jitter 0.7ps rms (at 155.52MHz, over 12kHz-20MHz), typ.
◆ Ideal for OC-48/STM-16 clock reference
◆ Output-to-output skew < 100ps
◆ External XTAL or LVCMOS reference input
◆ Integrated SAW (surface acoustic wave) delay line
◆ Single 3.3V power supply
◆ Small 9 x 9 mm SMT (surface mount) package
PIN ASSIGNMENT (9 x 9 mm SMT)
Figure 1: Pin Assignment
SIMPLIFIED BLOCK DIAGRAM
Example Output Frequency Configurations
(M908-02-155.5200)
Ref Clock
Frequency
(MHz)
PLL
Multiplication
Ratio
VCSO and
Output
Frequency
(MHz)
Application
19.44
8
155.52
OC-48/STM-16
nOP
OP
nO
P_
M908-02-155.52 (Other Frequencies Available)
External Loop Filter
M908-02 VCSO Based Clock Generator