P r o d u c t D a t a S h e e t
Integrated
Circuit
Systems, Inc.
M2020/21
VCSO BASED CLOCK PLL
G
ENERAL
D
ESCRIPTION
PIN
ASSIGNMENT (9 x 9 mm SMT)
The M2020/21 is a VCSO (Voltage Controlled SAW
Oscillator) based clock jitter
attenuator PLL designed for clock
jitter attenuation and frequency
translation. The device is ideal for
generating the transmit reference
clock for optical network systems
supporting 2.5-10 GB data rates.
FIN_SEL0
MR_SEL0
MR_SEL1
LOL
P_SEL0
P_SEL1
nFOUT0
FOUT0
GND
28
29
30
18
17
16
M2020
M2021
31
32
33
34
35
36
15
14
13
12
11
10
NBW
It can serve to jitter attenuate a
VCC
nFOUT1
FOUT1
VCC
stratum reference clock or a recovered clock in loop
timing mode. The M2020/21 module includes a
proprietary SAW (surface acoustic wave) delay line as
part of the VCSO. This results in a high frequency,
high-Q, low phase noise oscillator that assures low
intrinsic output jitter.
(Top View)
DNC
DNC
DNC
GND
F
EATURES
◆ Integrated SAW (surface acoustic wave) delay line;
low phase jitter of < 0.5ps rms, typical (12kHz to 20MHz
or 50kHz to 80MHz)
Figure 1: Pin Assignment
Example I/O Clock Frequency Combinations
Using M2020-11-622.0800 or M2021-11-622.0800
◆ Output frequencies of 15 to 700 MHz *
◆ LVPECL clock output (CML and LVDS options available)
PLL Ratio
Output Clock
(MHz)
Input Reference
◆ Reference clock inputs support differential LVDS,
LVPECL, as well as single-ended LVCMOS, LVTTL
(Pin Selectable)
Clock (MHz)
(M2020)
(M2021)
(M2020) (M2021)
◆ Loss of Lock (LOL) output pin
19.44 or 38.88
77.76
32 or 16
◆ Narrow Bandwidth control input (NBW pin)
8
4
1
622.08
155.52
622.08
◆ Hitless Switching (HS) options with or without Phase
Build-out (PBO) available for SONET (GR-253) /
SDH (G.813) MTIE and TDEV compliance during
reference clock reselection
Table 1: Example I/O Clock Frequency Combinations
* Specify VCSO center frequency at time of order.
◆ Industrial temperature grade available
◆ Single 3.3V power supply
◆ Small 9 x 9 mm SMT (surface mount) package
SIMPLIFIED
B
LOCK
D
IAGRAM
Loop
Filter
M2020/21
NBW
LOL
MUX
Phase
Detector
DIF_REF0
R Div
(1, 4,
16, 64)
0
1
nDIF_REF0
DIF_REF1
nDIF_REF1
VCSO
M
Mfin Div
(1, 4, 8, 32) or
( 1, 4, 8, 16)
Divider
(1, 4, 16, 64)
REF_SEL
2
M / R Divider
LUT
MR_SEL1:0
FOUT0
nFOUT0
P Divider
TriState
FOUT0: 1, 4, 8, 32 or TriState
FOUT1: 1, 4, 8 or TriState
2
3
Mfin Divider
LUT
FOUT1
FIN_SEL1:0
P_SEL2:0
nFOUT1
P Divider
LUT
Figure 2: Simplified Block Diagram
M2020/21 Datasheet Rev 1.1
Revised 20Jul2009
M2020/21 VCSO Based Clock PLL
Integrated Circuit Systems, Inc.
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Networking & Communications
●
www.icst.com
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tel (508) 852-5400