P r o d u c t D a t a S h e e t
Integrated
Circuit
Systems, Inc.
M1020/21
VCSO BASED CLOCK PLL
GENERAL DESCRIPTION
PIN ASSIGNMENT (9 x 9 mm SMT)
The M1020/21 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 up to 2.5Gb data rates.
It can serve to jitter attenuate a
MR_SEL2
MR_SEL0
MR_SEL1
LOL
P_SEL0
P_SEL1
nFOUT0
FOUT0
GND
nFOUT1
FOUT1
VCC
28
29
30
31
18
17
16
15
14
13
12
11
10
M1020
M1021
NBW
VCC
32
33
34
35
36
stratum reference clock or a recovered clock in loop
timing mode. The M1020/21 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.
( T o p V i e w )
DNC
DNC
DNC
GND
FEATURES
◆ Integrated SAW delay line; low phase jitter of < 0.5ps
rms, typical (12kHz to 20MHz)
Figure 1: Pin Assignment
◆ Output frequencies of 62.5 to 175 MHz
Example I/O Clock Frequency Combinations
Using M1020-11-155.5200 or M1021-11-155.5200
(Specify VCSO output frequency at time of order)
◆ LVPECL clock output (CML and LVDS options available)
◆ Reference clock inputs support differential LVDS,
PLL Ratio
Output Clock
Input Reference
Clock (MHz)
LVPECL, as well as single-ended LVCMOS, LVTTL
(Pin Selectable)
(MHz)
(Pin Selectable)
◆ Loss of Lock (LOL) output pin
(M1020)
(M1021)
(M1020) (M1021)
◆ Narrow Bandwidth control input (NBW pin)
19.44 or 38.88
8 or 4
2
1
155.52
or
77.76
◆ Hitless Switching (HS) options with or without Phase
Build-out (PBO) to enable SONET (GR-253) / SDH
(G.813) MTIE and TDEV compliance during reselection
77.76
155.52
622.08
0.25
◆ Pin-selectable feedback and reference divider ratios
◆ Industrial temperature grade available
◆ Single 3.3V power supply
Table 1: Example I/O Clock Frequency Combinations
◆ Small 9 x 9 mm SMT (surface mount) package
SIMPLIFIED BLOCK DIAGRAM
Loop
Filter
M1020/21
NBW
LOL
MUX
Phase
Detector
DIF_REF0
0
nDIF_REF0
R Div
VCSO
DIF_REF1
nDIF_REF1
1
M Divider
REF_SEL
4
2
M/R Divider
LUT
MR_SEL3:0
FOUT0
nFOUT0
P Divider
TriState
(1, 2, or TriState)
FOUT1
nFOUT1
P Divider
LUT
P_SEL1:0
Figure 2: Simplified Block Diagram
M1020/21 Datasheet Rev 1.0
Revised 28Jul2004
M1020/21 VCSO Based Clock PLL
Integrated Circuit Systems, Inc. ● Networking & Communications ● www.icst.com ● tel (508) 852-5400