M2086

更新时间:2024-10-29 07:33:32
品牌:ICSI
描述:VCSO FEC PLL WITH AUTOSWITCH FOR SONET/OTN

M2086 概述

VCSO FEC PLL WITH AUTOSWITCH FOR SONET/OTN 具有自动切换用于SONET / OTN VCSO FEC PLL

M2086 数据手册

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P r e l i m i n a r y I n f o r m a t i o n  
Integrated  
Circuit  
Systems, Inc.  
M2080/81/82  
M2085/86/87  
VCSO FEC PLL WITH AUTOSWITCH FOR SONET/OTN  
GENERAL DESCRIPTION  
PIN ASSIGNMENT (9 x 9 mm SMT)  
The M2080/81/82 and M2085/86/87 are VCSO (Voltage  
Controlled SAW Oscillator) based  
clock PLLs designed for FEC clock  
ratio translation in 10Gb optical  
systems such as OC-192 or 10GbE.  
They support FEC (Forward Error  
Correction) clock multiplication  
FIN_SEL0  
FEC_SEL0  
FEC_SEL1  
LOL  
P_SEL0  
P_SEL1  
nFOUT  
FOUT  
28  
29  
30  
31  
32  
33  
18  
17  
16  
15  
14  
13  
12  
11  
M2080  
Series  
ratios, both forward (mapping) and  
inverse (de-mapping). Multiplication ratios are  
pin-selected from pre-programming look-up tables.  
NBW  
VCC  
GND  
REF_ACK  
AUTO  
VCC  
( T o p V i e w )  
DNC  
DNC  
DNC  
34  
35  
36  
FEATURES  
10  
GND  
Integrated SAW delay line; Output of 15 to 700 MHz *  
Low phase jitter < 0.5 ps rms typical  
(12kHz to 20MHz or 50kHz to 80MHz)  
LVPECL clock output (CML and LVDS options available)  
Pin-selectable PLL divider ratios support FEC ratios  
Figure 1: Pin Assignment  
• M2080/85: OTU1 (255/238) and OTU2 (255/237) Mapping  
• M2081/86: OTU1 (238/255) or OTU2 (237/255) De-mapping  
• M2082/87: OTU1 (238/255) and OTU2 (237/255) De-mapping  
Example I/O Clock Frequency Combinations  
Using M2081-11-622.0800 FEC De-Map Ratios  
Reference clock inputs support differential LVDS,  
LVPECL, as well as single-ended LVCMOS, LVTTL  
FEC De-Map  
Base Input Rate 1  
(MHz)  
Output Clock  
(either output)  
MHz  
PLL Ratio  
Loss of Lock (LOL) output pin; Narrow Bandwidth  
control input (NBW pin)  
Mfec / Rfec  
AutoSwitch (AUTO pin) - automatic (non-revertive)  
1/1  
622.0800  
666.5143  
669.3266  
622.08  
or  
155.52  
reference clock reselection upon clock failure  
237/255  
238/255  
Acknowledge pin (REF_ACK pin) indicates the actively  
selected reference input  
Table 1: Example I/O Clock Frequency Combinations  
Options for Hitless Switching (HS) with or without  
Phase Build-out (PBO) to enable SONET (GR-253) /SDH  
(G.813) MTIE and TDEV compliance during reselection  
Note 1: Input reference clock can be the base frequency shown  
divided by “Mfin” (as shown in Tables 3 and 4 on pg. 3).  
* Specify VCSO center frequency at time of order.  
Single 3.3V power supply  
Small 9 x 9 mm SMT (surface mount) package  
SIMPLIFIED BLOCK DIAGRAM  
Loop Filter  
M2080 Series  
NBW  
PLL  
Phase  
MUX  
Detector  
DIF_REF0  
nDIF_REF0  
0
Rfec  
Div  
VCSO  
DIF_REF1  
nDIF_REF1  
1
REF_ACK  
REF_SEL  
M(f1in, 4,D8i,v3i2doerr  
Mfec Div  
0
1, 4, 8, 16)  
LOL Phase  
Detector  
1
LOL  
AUTO  
Auto  
FOUT  
Ref Sel  
P Divider  
nFOUT  
Tri-state  
(1, 4, 8, 32 or TriState)  
2
Mfec / Rfec Divider  
LUT  
FEC_SEL1:0  
2
3
Mfin Divider  
LUT  
FIN_SEL1:0  
P_SEL2:0  
P Divider  
LUT  
Figure 2: Simplified Block Diagram  
M2080/81/82 M2085/86/87 Datasheet Rev 0.4  
Revised 30Jul2004  
M2080/81/82 VCSO FEC PLL with AutoSwitch for SONET/OTN  
Integrated Circuit Systems, Inc. Networking & Communications www.icst.com tel (508) 852-5400  
M2080/81/82, M2085/86/87  
Integrated  
Circuit  
Systems, Inc.  
VCSO FEC PLL WITH  
A
UTO  
SWITCH FOR SONET/OTN  
P r e l i m i n a r y I n f o r m a t i o n  
PIN DESCRIPTIONS  
Number  
1, 2, 3, 10, 14, 26  
Name  
GND  
I/O  
Ground  
Configuration  
Description  
Power supply ground connections.  
4
9
OP_IN  
nOP_IN  
Input  
External loop filter connections.  
See Figure 5, External Loop Filter, on pg. 9.  
5
8
nOP_OUT  
OP_OUT  
Output  
6
7
nVC  
VC  
Input  
11, 19, 33  
VCC  
Power  
Power supply connection, connect to +3.3V.  
Automatic/manual reselection mode for clock input:  
Logic 1 automatic reselection upon clock failure  
(non-revertive)  
1
12  
AUTO  
Input  
Internal pull-down resistor  
Logic 0 manual selection only (using REF_SEL)  
Reference Acknowledgement pin for input mux state; outputs  
the currently selected reference input pair:  
Logic 1 indicates nDIF_REF1, DIF_REF1  
13  
REF_ACK  
Output  
Logic 0 indicates nDIF_REF0, DIF_REF0  
15  
16  
FOUT  
nFOUT  
Output No internal terminator  
Clock output pair. Differential LVPECL.  
17  
18  
25  
P_SEL1  
P_SEL0  
P_SEL2  
Post-PLL , P divider selection. LVCMOS/LVTTL. See Table 8,  
P Divider Look-Up Table (LUT), on pg. 4.  
1
Input  
Input  
Input  
Input  
Internal pull-down resistor  
2
20  
21  
nDIF_REF1  
DIF_REF1  
Biased to Vcc/2  
Reference clock input pair 1. Differential LVPECL or LVDS.  
1 Resistor bias on inverting terminal supports TTL or LVCMOS.  
Internal pull-down resistor  
Internal pull-down resistor  
Reference clock input selection. LVCMOS/LVTTL:  
Logic 1 selects DIF_REF1, nDIF_REF1.  
Logic 0 selects DIF_REF0, nDIF_REF0.  
1
22  
REF_SEL  
2
23  
24  
nDIF_REF0  
DIF_REF0  
Biased to Vcc/2  
Reference clock input pair 0. Differential LVPECL or LVDS.  
Resistor bias on inverting terminal supports TTL or LVCMOS.  
1
Internal pull-down resistor  
Internal pull-down resistor  
27  
28  
FIN_SEL1  
FIN_SEL0  
Input clock frequency selection. LVCMOS/LVTTL. See  
Tables 3 and 4 Mfin Divider Look-Up Tables (LUT) on pg. 3.  
1
Input  
Input  
29  
30  
FEC_SEL0  
FEC_SEL1  
Mfec and Rfec divider value selection. LVCMOS/ LVTTL.  
See Tables 5, 6, and 7 on pg. 3.  
1
Internal pull-down resistor  
Loss of Lock indicator output. Asserted when internal PLL is  
3
not tracking the input reference for frequency and phase.  
Logic 1 indicates loss of lock.  
31  
LOL  
Output  
Input  
Logic 0 indicates locked condition.  
Narrow Bandwidth enable. LVCMOS/LVTTL:  
Logic 1 - Narrow loop bandwidth, RIN = 2100k.  
Logic 0 - Wide bandwidth, RIN = 100k.  
1
32  
NBW  
DNC  
Internal pull-UP resistor  
34, 35, 36  
Do Not Connect.  
Table 2: Pin Descriptions  
Note 1: For typical values of internal pull-down and pull-UP resistors, see DC Characteristics on pg. 11.  
Note 2: Biased toVcc/2, with 50kto Vcc and 50kto ground. See Differential Inputs Biased to VCC/2 on pg. 11.  
Note 3: See LVCMOS Outputs in DC Characteristics on pg. 11.  
M2080/81/82 M2085/86/87 Datasheet Rev 0.4  
2 of 14  
Revised 30Jul2004  
Integrated Circuit Systems, Inc. Networking & Communications www.icst.com tel (508) 852-5400  
M2080/81/82, M2085/86/87  
Integrated  
Circuit  
Systems, Inc.  
VCSO FEC PLL WITH  
A
UTO  
SWITCH FOR SONET/OTN  
P r e l i m i n a r y I n f o r m a t i o n  
DETAILED BLOCK DIAGRAM  
RLOOP CLOOP  
RPOST  
External  
Loop Filter  
Components  
CPOST  
CPOST  
RLOOP CLOOP  
nOP_IN OP_OUT  
RPOST  
M2080 Series  
OP_IN  
nOP_OUT  
nVC  
VC  
NBW  
PLL  
Phase  
MUX  
SAW Delay Line  
RIN  
RIN  
Detector  
DIF_REF0  
0
Phase  
Locked  
Loop  
(PLL)  
Rfec  
Div  
nDIF_REF0  
DIF_REF1  
nDIF_REF1  
Loop Filter  
Amplifier  
Phase  
Shifter  
1
VCSO  
REF_ACK  
REF_SEL  
Mfin Divider  
Mfec Div  
(1, 4, 8, 32) or  
(1, 4, 8, 16)  
0
1
LOL  
Phase  
AUTO  
Detector  
Auto  
LOL  
Ref Sel  
FOUT  
nFOUT  
2
2
Mfec / Rfec  
Divider LUT  
FEC_SEL1:0  
FIN_SEL1:0  
P Divider  
(1, 4, 8, 32,  
or TriState)  
Mfin Divider  
LUT  
CML or PECL  
Options  
3
P Divider  
LUT  
P_SEL2:0  
Figure 3: Detailed Block Diagram  
Mfec and Rfec Divider Look-Up Tables (LUTs)  
DIVIDER SELECTION TABLES  
Mfin Divider Look-Up Tables (LUT)  
The FEC_SEL pins select the Mfec/Rfec divider ratio. The  
look-up tables vary by device variant. The Mfec and  
Rfec values also establish phase detector frequency.  
A lower phase detector frequency improves jitter  
tolerance and lowers loop bandwidth.  
The FIN_SEL1:0 pins select the feedback divider value  
(“Mfin”), which sets the overall PLL ratio range. Since  
the VCSO frequency is fixed, this allows input reference  
selection. The look-up tables vary by device variant.  
M2080/85: FEC Map LUT, OTU1 (255/238) and OTU2 (255/237)  
Fvcso =  
FEC_SEL1:0  
0
Base Input  
Mfec Rfec  
Base Output  
Rate (MHz)  
Description  
M2080/81/82: Mfin Value LUT (Includes Divide by 32)  
Rate (MHz)  
1
Mfin  
Sample Input Reference Freq. (MHz) Options  
FIN_SEL1:0  
1
2
For M2080 or M2085 with Fvcso = 666.5143 (OTU1 FEC rate):  
255/238 OC-48 to OTU1 encode  
For M2080 , M2081 & M2082  
Value  
0
0
0
1
15 14  
15 15  
622.08 666.5143  
666.5143 666.5143  
0 0  
0 1  
1 0  
1 1  
32  
8
4
1
19.44  
77.76  
155.52  
622.08  
OTU1 repeater or jitter attenuator  
For M2080 or M2085 with Fvcso = 669.3266 (OTU2 FEC rate):  
255/237 OC-192 to OTU2 encode  
1
1
0
1
85 79  
85 85  
622.08 669.3266  
669.3266 669.3266  
Table 3: M2080/81/82: Mfin Value LUT (Includes Divide by 32)  
OTU2 repeater or jitter attenuator  
Note 1: For M2080 with Fvcso = 666.5143 or 669.3266  
Note 2: For M2081 and M2082 with Fvcso = 622.0800.  
Table 5: M2080/85: FEC Map LUT, OTU1 (255/238) and OTU2 (255/237)  
M2081/86: FEC De-map LUT, OTU1 (238/255) or OTU2 (237/255)  
M2085/86/87: Mfin Value LUT (Includes Divide by 16)  
Use this option for either OTU1 or OTU2 de-mapping  
Mfin  
Sample Input Reference Freq. (MHz) Options  
FIN_SEL1:0  
1
2
For M2085 , M2086 & M2087  
Value  
applications, but not both.  
FEC_SEL1:0  
Fvcso =  
0 0  
0 1  
1 0  
1 1  
16  
8
4
1
38.88  
77.76  
155.52  
Base Input  
Mfec Rfec  
Base Output  
Rate (MHz)  
Description  
Rate (MHz)  
1
0
For M2081 or M2086 with Fvcso = 622.08 (OTU1 or OTU2 FEC rate):  
622.08  
237/255 OTU2 to OC-192 decode  
0
0
1
1
0
1
0
1
79 85  
79 79  
14 15  
14 14  
669.3266 622.08  
Table 4: M2085/86/87: Mfin Value LUT (Includes Divide by 16)  
OC-192 repeater or jitter attenuator  
238/255 OTU1 to OC-48 decode  
OC-48 repeater or jitter attenuator  
622.08  
666.5143 622.08  
622.08  
622.08  
Note 1: For M2085 with Fvcso = 666.5143 or 669.3266  
Note 2: For M2086 and M2087 with Fvcso = 622.0800.  
622.08  
Table 6: M2081/86: FEC De-map LUT, OTU1 (238/255) or OTU2 (237/255)  
M2080/81/82 Datasheet Rev 0.4  
3 of 14  
Revised 30Jul2004  
Integrated Circuit Systems, Inc. Networking & Communications www.icst.com tel (508) 852-5400  
M2080/81/82, M2085/86/87  
Integrated  
Circuit  
Systems, Inc.  
VCSO FEC PLL WITH  
A
UTO  
SWITCH FOR SONET/OTN  
P r e l i m i n a r y I n f o r m a t i o n  
M2082/87: FEC De-map LUT, Both OTU1 and OTU2  
Use this option for both OTU1 or OTU2 de-mapping  
applications. The Mfec divider value is kept nearly  
constant to maintain similar loop bandwidth using one  
set of external filter component values.  
FUNCTIONAL DESCRIPTION  
The M208x Series is a PLL (Phase Locked Loop) based  
clock generator that generates output clocks synchro-  
nized to one of two selectable input reference clocks.  
An internal high "Q" SAW delay line provides low jitter  
signal performance and establishes the output  
frequency of the VCSO (Voltage Controlled SAW  
Oscillator). In a given M208x Series device, the VCSO  
center frequency is fixed. A common center frequency  
is 622.08MHz, for SONET or SDH optical network  
applications. The VCSO center frequency is specified at  
time of order (see “Ordering Information” on pg. 14).  
The VCSO has a guaranteed tuning range of ±120 ppm  
(commercial temperature grade).  
Fvcso =  
FEC_SEL1:0  
0
Base Input  
Mfec Rfec  
Base Output  
Rate (MHz)  
Description  
Rate (MHz)  
1
For M2082 or M2087 with Fvcso = 622.08 (OTU1 or OTU2 FEC rate):  
237/255 OTU2 to OC-192 decode  
0
0
1
1
0
1
0
1
79 85  
79 79  
84 90  
84 84  
669.3266 622.08  
OC-192 repeater or jitter attenuator  
238/255 OTU1 to OC-48 decode  
OC-48 repeater or jitter attenuator  
622.08  
666.5143 622.08  
622.08 622.08  
622.08  
Table 7: M2082/87: FEC De-map LUT, Both OTU1 and OTU2  
P Divider Look-Up Table (LUT)  
Pin selectable dividers are used within the PLL and  
for the output clock. This enables tailoring of device  
functionality and performance. The FEC feedback and  
reference dividers (the “Mfec Divider” and “Rfec  
Divider”) provide the multiplication ratios necessary to  
accomodate clock translation for both forward and  
inverse Forward Error Correction. The Mfec and Rfec  
dividers also control the phase detector frequency. The  
feedback divider (labeled “Mfin Divider”) provides the  
broader division options needed to accomodate various  
reference clock frequencies.  
The P_SEL2:0 pins select the P divider values, which set  
the output clock frequency. A P divider of value of 1 will  
provide a 622.08MHz output when using a 622.08MHz  
VCSO, for example. P divider values of 4, 8, or 32 are  
also available, plus a TriState mode. The output can be  
placed into the valid states as listed in Table 8.  
M2080-622.0800 or M2085-622.0800  
P_SEL2:0  
P Value  
Output Frequency (MHz)  
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
32  
32  
1
4
8
4
8
19.44  
19.44  
622.08  
155.52  
77.76  
155.52  
77.76  
N/A  
For example, the M2082-11-622.0800 (see “Ordering  
Information” on pg. 14) has a 622.08MHz VCSO  
frequency:  
The FEC de-mapper PLL ratios (in Tables 6 and 7)  
enable the M2082-11-622.0800 to accept “base” input  
reference frequencies of: 666.5143 (OTU1), 669.3266  
(OTU2), and 622.08MHz (OC-192).  
TriState  
Table 8: P Divider Look-Up Table (LUT)  
The Mfin feedback divider enables the actual input  
reference clock to be the base input frequency  
divided by 1, 4, 8, or 32 or 16. Therefore, for the base  
input frequency of 622.08MHz, the actual input  
reference clock frequencies can be: 622.08, 155.52,  
77.76, and 19.44 or 38.88MHz. (See Tables 3 and 4 on  
pg. 3.)  
General Guidelines for Phase Detector Frequency  
The phase detector frequency (Fpd) is equal to the  
input reference frequency (Fref) divided by the Rfec  
divider value, or:  
Fpd = Fref / Rfec  
A lower phase detector frequency should be used for  
loop timing applications to assure PLL tracking,  
especially during GR-253 jitter tolerance testing. The  
recommended maximum phase detector frequency  
for loop timing mode is 19.44MHz.  
Key to Device Variants and Look-up Table Options  
Device  
Variant  
Look-up Table Option  
Mfin Lookup Table is:  
Mfec Look-up Table is:  
M2080  
M2081  
M2082  
M2085  
M2086  
M2087  
Table 5 (FEC mapper LUT)  
Table 6 (FEC de-mapper LUT)  
Table 7 (FEC de-mapper LUT)  
Table 5 (FEC mapper LUT)  
Table 6 (FEC de-mapper LUT)  
Table 7 (FEC de-mapper LUT)  
Table 3  
When LOL is to be used for system health monitoring,  
the phase detector frequency should be 5MHz or  
greater. Low phase detector frequencies make LOL  
overly sensitive, and higher phase detector  
frequencies make LOL less sensitive. The LOL pin  
should not be used during loop timing mode.  
(includes divider value 32)  
Table 4  
(includes divider value 16)  
Table 9: Key to Device Variants and Look-up Table Options  
The preceding guideline also applies when using the  
AutoSwitch Mode, since AutoSwitch uses the LOL  
output for clock fault detection.  
The P divider scales the VCSO output enabling lower  
output frequency selections (Table 8).  
M2080/81/82 M2085/86/87 Datasheet Rev 0.4  
4 of 14  
Revised 30Jul2004  
Integrated Circuit Systems, Inc. Networking & Communications www.icst.com tel (508) 852-5400  
M2080/81/82, M2085/86/87  
Integrated  
Circuit  
Systems, Inc.  
VCSO FEC PLL WITH  
A
UTO  
S
WITCH FOR SONET/OTN  
P r e l i m i n a r y I n f o r m a t i o n  
The M208x Series includes a Loss of Lock (LOL)  
indicator, which provides status information to system  
management software. A Narrow Bandwidth (NBW)  
control pin is provided as an additional mechanism for  
adjusting PLL loop bandwidth without affecting the  
phase detector frequency.  
Differential Inputs  
Differential LVPECL inputs are connected to both  
reference input pins in the usual manner. The external  
load termination resistors shown in Figure 4 (the 127Ω  
and 82resistors) is ideally suited for both AC and DC  
coupled LVPECL reference clock lines. These provide  
the 50load termination and the VTT bias voltage.  
Options are available for Hitless Switching (HS) with or  
without Phase Build-out (PBO). They provide SONET/  
SDH MTIE and TDEV compliance during a reference  
clock reselection.  
Single-ended Inputs  
Single-ended inputs (LVCMOS or LVTTL) are  
connected to the non-inverting reference input pin  
(DIF_REF0 or DIF_REF1). The inverting reference input pin  
(nDIF_REF0 or nDIF_REF1) must be left unconnected.  
Input Reference Clocks  
Two clock reference inputs and a selection mux are  
provided. Either reference clock input can accept a  
differential clock signal (such as LVPECL or LVDS) or  
a single-ended clock input (LVCMOS or LVTTL on the  
non-inverting input).  
In single-ended operation, when the unused inverting  
input pin (nDIF_REF0 or nDEF_REF1) is left floating (not  
connected), the input will self-bias at VCC/2.  
A single-ended reference clock on the unselected  
reference input can cause an increase in output  
clock jitter. For this reason, differential reference  
inputs are preferred; interference from a differential  
input on the non-selected input is minimal.  
PLL Operation  
The M2080/81/82 and M2085/86/87 are complete clock  
PLLs. They use a phase detector and configurable  
dividers to synchronize the output of the VCSO with the  
selected reference clock.  
Configuration of a single-ended input has been  
facilitated by biasing nDIF_REF0 and nDEF_REF1 to Vcc/2,  
with 50kto Vcc and 50kto ground. The input clock  
structure, and how it is used with either  
LVCMOS/LVTTL inputs or a DC- coupled LVPECL  
clock, is shown in Figure 4.  
The M208x Series components are similar to the  
M2060 Series components except that the M208x  
Series includes the selectable AutoSwitch feature. The  
M208x Series also has only one clock output, as the  
AutoSwitch control pins replace of the second output.  
The PLL will work correctly, meaning it will phase-lock  
the VCSO output to the input reference clock, when the  
internal phase detector inputs are able to run at the  
same frequency. This means the PLL dividers must be  
set appropriately and a suitable reference frequency  
must be chosen for the intended output frequency.  
When the PLL is not set up appropriately, the VCSO is  
forced to its upper or lower operating limit which is typi-  
cally about 200 ppm above or below the VCSO center  
frequency. See “APR, VCSO Absolute Pull-Range” row,  
in the AC Characteristics table on pg. 12.  
.
DIF_REF0  
LVCMOS/  
LVTTL  
VCC  
MUX  
50k  
50k  
0
nDIF_REF0  
X
VCC  
50k  
1
127Ω  
DIF_REF1  
VCC  
VCC  
50k  
82  
LVPECL  
127  
50k  
In normal phase-locked condition, the instantaneous  
phase error is measured by the phase detector and is  
converted to charge pump current pulses. These  
current pulses are then integrated by the external loop  
filter to create a VCSO control voltage. The loop filter  
acts as a low pass filter to remove unwanted reference  
clock jitter above a determined frequency or PLL  
bandwidth. For reference phase jitter frequencies within  
the loop bandwidth, phase jitter amplitude is passed on  
to the output clock according to the PLL loop frequency  
response curve.  
nDIF_REF1  
REF_SEL  
82  
50k  
Figure 4: Input Reference Clocks  
M2080/81/82 Datasheet Rev 0.4  
5 of 14  
Revised 30Jul2004  
Integrated Circuit Systems, Inc. Networking & Communications www.icst.com tel (508) 852-5400  
M2080/81/82, M2085/86/87  
Integrated  
Circuit  
Systems, Inc.  
VCSO FEC PLL WITH  
A
UTO  
SWITCH FOR SONET/OTN  
P r e l i m i n a r y I n f o r m a t i o n  
The relationship between the nominal VCSO center  
frequency (Fvcso), the Mfin divider, the Mfec divider,  
the Rfec divider, and the input reference frequency (Fin)  
Loss of Lock Indicator (LOL) Output Pin  
Under normal device operation, when the PLL is locked,  
the LOL Phase Detector drives LOL to logic 0. Under  
circumstances when the VCSO cannot fully phase lock  
to the input (as measured by a greater than 4 ns  
discrepancy between the feedback and reference clock  
rising edges at the LOL Phase Detector) the LOL output  
goes to logic 1. The LOL pin will return back to logic 0  
when the phase detector error is less than 2 ns. The  
loss of lock indicator is a low current LVCMOS output.  
is:  
Mfec  
Rfec  
-------------  
Fvcso = Fin × Mfin ×  
The Mfec, Rfec, and Mfin dividers can be set by pin  
configuration using the input pins FEC_SEL1, FEC_SEL0,  
FIN_SEL1, and FIN_SEL0.  
Post-PLL Divider  
The M2080/81/82 and M2085/86/87 also feature a  
post-PLL (P) divider.  
Guidelines for Using LOL  
In a given application, the magnitude of peak-to-peak  
jitter at the phase detector will usually increase as the  
Rfec divider is increased. If the LOL pin will be used to  
detect an unusual clock condition, or a clock fault, the  
FEC_SEL1:0 pins should be set to provide a phase  
detector frequency of 5MHz or greater (the phase  
detector frequency is equal to Fin divided by the Rfec  
divider). Otherwise, false LOL indications may result. A  
phase detector frequency of 10MHz or greater is  
desirable when reference jitter is over 500ps, or when  
the device is used within a noisy system environment.  
LOL should not be used when the device is used in a  
loop timing application.  
Through use of the P divider, the device’s output  
frequency (Fout) can be that of the VCSO (such as  
622.08MHz) or the VCSO frequency divided by 4, 8 or 32  
(common optical reference clocks in SONET and SDH  
systems).  
The P_SEL2:0 pins select the value for the P divider. (See  
Table 8 on pg. 4.)  
Accounting for the P divider, the complete relationship  
between the input clock reference frequency (Fin) and  
output clock frequency (Fout) is defined as:  
Mfin × Mfec  
Fvcso  
---------------------------------  
Fout =  
= Fin ×  
-------------------  
Rfec × P  
P
Due to the narrow tuning range of the VCSO (+120ppm  
guaranteed), appropriate selection of all of the following  
are required for the PLL be able to lock: VCSO center  
frequency, input frequency, and divider selections.  
TriState  
The TriState feature puts the LVPECL output driver into  
a high impedance state, effectively disconnecting the  
driver from the FOUT and nFOUT pins of the device. In  
TriState, the M208x Series is not driving the output  
clock net with a defined logic level. The impedance of  
the clock net is then set to 50by the external circuit  
resistors. The 50impedance level of the LVPECL  
TriState allows manufacturing In-circuit Test to drive the  
clock net with an external LVPECL source to validate  
the integrity of clock net and the clock load.  
Any unused output (single-ended or differential) should  
be left unconnected (floating) in system application.  
This minimizes output switching current and therefore  
minimizes noise modulation of the VCSO.  
M2080/81/82 M2085/86/87 Datasheet Rev 0.4  
6 of 14  
Revised 30Jul2004  
Integrated Circuit Systems, Inc. Networking & Communications www.icst.com tel (508) 852-5400  
M2080/81/82, M2085/86/87  
Integrated  
Circuit  
Systems, Inc.  
VCSO FEC PLL WITH  
A
UTO  
SWITCH FOR SONET/OTN  
P r e l i m i n a r y I n f o r m a t i o n  
REF_ACK output always indicates the reference selection  
status and the LOL output always indicates the PLL lock  
status.  
AutoSwitch (AUTO) Reference Clock Reselection  
This device offers an automatic reference clock  
reselection feature for switching input reference clocks  
upon a reference clock failure. With the AUTO input pin  
set to high and the LOL output low, the device is placed  
into automatic reselection (AutoSwitch) mode. Once in  
AutoSwitch mode, when LOL then goes high (due to a  
reference clock fault), the input clock reference is  
automatically reselected internally, as indicated by the  
state change of the REF_ACK output. Automatic clock  
reselection is made only once (it is non-revertive).  
Re-arming of automatic mode requires placing the  
device into manual selection (Manual Select) mode  
(AUTO pin low) before returning to AutoSwitch mode  
(AUTO pin high).  
A successful automatic reselection is indicated by a  
change of state of the REF_ACK output and a momentary  
level high of the LOL output (minimum high time is 10  
ns).  
If an automatic reselection is made to a non-valid  
reference clock (one to which the PLL cannot lock),  
the REF_ACK output will change state but the LOL  
output will remain high.  
No further automatic reselection is made; only one  
reselection is made each time the AutoSwitch mode is  
armed. AutoSwitch mode is re-armed by placing the  
device into Manual Select mode (AUTO pin low) and then  
into AutoSwitch mode again (AUTO pin high).  
Using the AutoSwitch Feature  
Following an automatic reselection and prior to  
selecting Manual Select mode (AUTO pin low), the  
REF_SEL pin has no control of reference selection.  
To prevent an unintential reference reselection,  
AutoSwitch mode must not be re-enabled until the  
desired state of the REF_SEL pin is set and the LOL output  
is low. It is recommended to delay the re-arming of  
AutoSwitch mode, following an automatic reselection, to  
ensure the PLL is fully locked on the new reference. In  
most system configurations, where loop bandwidth is in  
the range of 100-1000 Hz and damping factor below 10,  
a delay of 500 ms should be sufficient. Until the PLL is  
fully locked intermittent LOL pulses may occur.  
See also Table 10, Example AutoSwitch Sequence.  
In application, the system is powered up with the device  
in Manual Select mode (AUTO pin is set low), allowing  
sufficient time for the reference clock and device PLL to  
settle. The REF_SEL input selects the reference clock to  
be used in Manual Select mode and the initial reference  
clock used in AutoSwitch mode. The REF_SEL input state  
must be maintained when switching to AutoSwitch  
mode (AUTO pin high) and must still be maintained until a  
reference fault occurs.  
Once a reference fault occurs, the LOL output goes high  
and the input reference is automatically reselected. The  
Example AutoSwitch Sequence  
0 = Low; 1 = High. Example with REF_SEL initially set to 0 (i.e., DIF_REF0 selected)  
Selected  
Clock Input  
REF_SEL  
Input  
REF_ACK AUTO LOL Conditions  
Output Input Output  
Initialization  
0
0
0
0
0
0
0
0
1
-0-  
0
DIF_REF0  
DIF_REF0  
DIF_REF0  
Device power-up. Manual Select mode. DIF_REF0 input selected reference, not yet locked to.  
LOL to 0: Device locked to reference (may get intermittent LOL pulses until fully locked).  
-1-  
AUTO set to 1: Device placed in AutoSwitch mode (with DIF_REF0 as initial reference clock).  
Operation & Activation  
0
0
1
0
DIF_REF0  
Normal operation with AutoSwitch mode armed, with DIF_REF0 as initial reference clock.  
DIF_REF0  
0
0
0
-1-  
1
1
-1-  
1
LOL to 1: Clock fault on DIF_REF0, loss of lock indicated by LOL pin, ...  
... and immediate automatic reselection to DIF_REF1 (indicated by REF_ACK pin).  
-DIF_REF1-  
0
1
1
-0-  
DIF_REF1  
LOL to 0: Device locks to DIF_REF1 (assuming valid clock on DIF_REF1).  
Re-initialization  
-1-  
1
1
1
1
1
0
0
0
DIF_REF1  
DIF_REF1  
DIF_REF1  
REF_SEL set to 1: Prepares for Manual Selection of DIF_REF1 before then re-arming AutoSwitch.  
-0-  
-1-  
AUTO set to 0: Manual Select mode entered briefly, manually selecting DIF_REF1 as reference.  
1
AUTO set to 1: Device is placed in AutoSwitch mode (delay recommended to ensure device fully  
locked), re-initializing AutoSwitch with DIF_REF1 now specified as the initial reference clock.  
Table 10: Example AutoSwitch Sequence  
M2080/81/82 Datasheet Rev 0.4  
7 of 14  
Revised 30Jul2004  
Integrated Circuit Systems, Inc. Networking & Communications www.icst.com tel (508) 852-5400  
M2080/81/82, M2085/86/87  
Integrated  
Circuit  
Systems, Inc.  
VCSO FEC PLL WITH  
A
UTO  
S
WITCH FOR SONET/OTN  
P r e l i m i n a r y I n f o r m a t i o n  
HS/PBO Operation  
Optional Hitless Switching and Phase Build-out  
Once triggered, the following HS/PBO sequence  
occurs:  
The M208x Series is available with a Hitless Switching  
feature that is enabled during device manufacturing.  
In addition, a Phase Build-out feature is also offered.  
These features are offered as device options and are  
specified by device order code. Refer to “Ordering  
Information” on pg. 14.  
1.The HS function disables the PLL Phase Detector  
and puts the device into NBW (narrow bandwidth)  
mode. The internal resistor Rin is changed to  
2100k. See the Narrow Bandwidth (NBW) Control  
Pin on pg. 8.  
The Hitless Switching feature (with or without Phase  
Build-out) is designed for applications where switching  
occurs between two stable system reference clocks. It  
should not be used in loop timing applications, or when  
reference clock jitter is greater than 1 ns pk-pk. The  
Hitless Switching sequence is triggered by the LOL  
circuit, which is activated by a 4 ns phase transient. This  
magnitude of phase transient can generated by the  
CDR (Clock & Data Recovery unit) in loop timing mode,  
especially during a system jitter tolerance test. It can  
also be generated by some types of Stratum clock  
DPLLs (digital PLL), especially those that do not include  
a post de-jitter APLL (analog PLL).  
2.If included, the PBO function adds to (builds out) the  
phase in the clock feedback path (in VCSO clock  
cycle increments) to align the feedback clock with  
the (new) reference clock input phase.  
3.The PLL Phase Detector is enabled, allowing the  
PLL to re-lock.  
4.Once the PLL Phase Detector feedback and input  
clocks are locked to within 2 nsec for 8 consecutive  
cycles, a timer (WBW timer) for resuming wide  
bandwidth (in 175 nsec) is started.  
5.When the WBW timer times out, the device reverts  
to wide loop bandwidth mode (i.e., Rin is returned to  
100k) and the HS/PBO function is re-armed.  
The LOL pin will indicate lock status on a cycle-to-cycle  
basis and may be intermittent until PLL phase lock has  
fully stabilized.  
When the M208x Series is operating in wide bandwidth  
mode (NBW=0), the optional Hitless Switching function  
puts the device into narrow bandwidth mode when  
during the Hitless Switching sequence. This allows the  
PLL to lock the new input clock phase gradually. With  
proper configuration of the external loop filter, the output  
clock phase change complies with MTIE and TDEV  
specifications for GR-253 (SONET) and ITU G.813  
(SDH) during input reference clock changes.  
Narrow Bandwidth (NBW) Control Pin  
A Narrow Loop Bandwidth control pin (NBW pin) is  
included to enable adjustment of the PLL loop  
bandwidth. In wide bandwidth mode (NBW=0), the  
internal resistor Rin is 100k. With the NBW pin  
asserted (NBW=1), the internal resistor Rin is changed to  
2100k. This lowers the loop bandwidth by a factor of  
about 21 (2100 / 100) and lowers the damping factor by  
about 4.6 (the square root of 21), assuming the same  
external loop filter component values.  
The optional proprietary Phase Build-out (PBO)  
function enables the PLL to absorb most of the phase  
change of the input clock during reference switching.  
The PBO function selects a new VCSO clock edge for  
the PLL Phase Detector feedback clock, selecting the  
edge closest in phase to the new input clock phase.  
This reduces re-lock time, the generation of wander,  
and extra output clock cycles.  
The Hitless Switching and Phase Build-out functions  
are triggered by the LOL circuit. For proper operation,  
a low phase detector frequency must be avoided. See  
“Guidelines for Using LOLon pg. 6 for information  
regarding the phase detector frequency.  
HS/PBO Sequence Trigger Mechanism  
The HS function (or the combined HS/PBO function)  
is armed after the device locks to the input clock refer-  
ence. Once armed, HS is triggered by the occurance of  
a Loss of Lock condition. This would typically occur as a  
consequence of a clock reference failure, a clock failure  
upstream to the M208x Series, or a M208x Series clock  
reference mux reselection.  
M2080/81/82 M2085/86/87 Datasheet Rev 0.4  
8 of 14  
Revised 30Jul2004  
Integrated Circuit Systems, Inc. Networking & Communications www.icst.com tel (508) 852-5400  
M2080/81/82, M2085/86/87  
Integrated  
Circuit  
Systems, Inc.  
VCSO FEC PLL WITH  
A
UTO  
SWITCH FOR SONET/OTN  
P r e l i m i n a r y I n f o r m a t i o n  
External Loop Filter  
PLL Simulator Tool Available  
To provide stable PLL operation, the M2080/81/82  
requires the use of an external loop filter. This is  
provided via the provided filter pins (see Figure 5).  
The loop filter is implemented as a differential circuit  
to minimize system noise interference.  
A free PC software utility is available on the ICS website  
(www.icst.com). The M2000 Timing Modules PLL  
Simulator is a downloadable application that simulates  
PLL jitter and wander transfer characteristics. This  
enables the user to set appropriate external loop  
component values in a given application.  
RLOOP CLOOP  
RPOST  
CPOST  
CPOST  
RLOOP CLOOP  
nOP_IN OP_OUT  
RPOST  
OP_IN  
nOP_OUT  
nVC  
VC  
4
9
8
5
6
7
Figure 5: External Loop Filter  
PLL bandwidth is affected by loop filter component  
values, “Mfec” and “Mfin” values, and the “PLL Loop  
Constants” listed in AC Characteristics on pg. 12.  
The FEC_SEL setting can be used to actively change PLL  
loop bandwidth in a given application. See “Mfec and  
Rfec Divider Look-Up Tables (LUTs)” on pg. 3.  
See Table 11, Example Values for Loop Filter External  
Components, below.  
1
Example Values for Loop Filter External Components  
for Particular M208x Series Devices  
VCSO Parameters: K  
= 800kHz/V, R = 100k  
(pin NBW = 0), VCSO Bandwidth = 700kHz.  
VCO  
IN  
Device  
Device Configuration  
Example External Component Values  
Nominal Performance With These Values  
FIN_SEL MRSEL  
1:0  
FRef  
FVCSO  
R loop  
C loop  
R post  
C post  
PLL Loop Damping Passband  
1:0  
Bandwidth Factor Peaking(dB)  
(MHz)  
(MHz)  
M2080, M2080 622.08 622.08  
1 1  
0 1  
6.5  
5.9  
6.5  
6.5  
0.05  
0.06  
0.05  
0.05  
5.6kΩ  
243.0kΩ  
8.2kΩ  
10µF  
0.1µF  
10µF  
10µF  
68kΩ  
34kΩ  
100kΩ  
100kΩ  
470pF  
470pF  
470pF  
470pF  
530Hz  
1kHz  
M2080, M2085 155.52 669.3266 1 0  
1 0 0  
0 1  
M2081, M2086 77.76 622.08  
M2081  
0 1  
0 0  
360Hz  
360Hz  
19.44 622.08  
1 1  
8.2kΩ  
Table 11: Example Values for Loop Filter External Components  
Note 1: KVCO , VCSO Bandwidth, M Divider Value, and External Loop Filter Component Values determine Loop Bandwidth, Damping Factor, and  
Passband Peaking. For PLL Simulator software, go to www.icst.com.  
Refer to the M208x Series product web page at  
www.icst.com/products/summary/m2080-2087.htm  
for additional product information.  
M2080/81/82 Datasheet Rev 0.4  
9 of 14  
Revised 30Jul2004  
Integrated Circuit Systems, Inc. Networking & Communications www.icst.com tel (508) 852-5400  
M2080/81/82, M2085/86/87  
Integrated  
Circuit  
Systems, Inc.  
VCSO FEC PLL WITH  
A
UTO  
SWITCH FOR SONET/OTN  
P r e l i m i n a r y I n f o r m a t i o n  
1
ABSOLUTE MAXIMUM RATINGS  
Symbol Parameter  
Rating  
-0.5 to VCC +0.5  
Unit  
VI  
Inputs  
V
VO  
VCC  
TS  
Outputs  
-0.5 to VCC +0.5  
4.6  
V
V
Power Supply Voltage  
Storage Temperature  
-45 to +100  
oC  
Table 12: Absolute Maximum Ratings  
Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the  
device. These ratings are stress specifications only. Functional operation of product at these conditions  
or any conditions beyond those listed in Recommended Conditions of Operation, DC Characteristics, or  
AC Characteristics is not implied. Exposure to absolute maximum rating conditions for extended periods  
may affect product reliability  
.
RECOMMENDED CONDITIONS OF OPERATION  
Symbol Parameter  
Min  
Typ  
Max Unit  
VCC  
Positive Supply Voltage  
3.135  
3.3  
3.465  
V
TA  
Ambient Operating Temperature  
oC  
oC  
0
Commercial  
Industrial  
+70  
+85  
-40  
Table 13: Recommended Conditions of Operation  
M2080/81/82 M2085/86/87 Datasheet Rev 0.4  
10 of 14  
Revised 30Jul2004  
Integrated Circuit Systems, Inc. Networking & Communications www.icst.com tel (508) 852-5400  
M2080/81/82, M2085/86/87  
Integrated  
Circuit  
Systems, Inc.  
VCSO FEC PLL WITH  
A
UTO  
SWITCH FOR SONET/OTN  
P r e l i m i n a r y I n f o r m a t i o n  
ELECTRICAL SPECIFICATIONS  
DC Characteristics  
Unless stated otherwise, VCC  
= 3.3V +5 = 622-675MHz,  
%,TA = 0 oC to +70 oC (commercial), TA = -40 oC to +85 oC (industrial), FVCSO = FOUT  
LVPECL outputs terminated with 50to VCC - 2V  
Symbol Parameter  
Power Supply VCC Positive Supply Voltage  
Min  
3.135  
Typ  
3.3  
Max Unit Conditions  
3.465  
V
175  
225  
ICC  
VP-P  
VCMR  
CIN  
IIH  
Power Supply Current  
mA  
V
0.15  
0.5  
All  
Differential  
Inputs  
Peak to Peak Input Voltage  
Common Mode Input  
DIF_REF0, nDIF_REF0,  
DIF_REF1, nDIF_REF1  
V
- .85  
V
cc  
4
Input Capacitance  
pF  
VCC = VIN  
3.456V  
=
Differential  
Inputs with  
Pull-down  
Input High Current (Pull-down)  
Input Low Current (Pull-down)  
Internal Pull-down Resistance  
Input High Current (Biased) 1  
Input Low Current (Biased) 1  
150 µA  
µA  
DIF_REF0, DIF_REF1  
IIL  
-5  
50  
R
kΩ  
pulldown  
VIN  
0 to 3.456V  
=
150  
Differential  
Inputs  
Biased to  
IIH  
IIL  
µA  
nDIF_REF0, nDIF_REF1  
-150  
µA  
R
Biased to Vcc/2 1  
kΩ  
1
(Note 1)  
VCC/2  
bias  
AUTO, REF_SEL, FIN_SEL1,  
FIN_SEL0, FEC_SEL1,  
FEC_SEL0, P_SEL2, P_SEL1,  
P_SEL0, NBW  
2
All LVCMOS VIH  
/ LVTTL  
Input High Voltage  
Input Low Voltage  
V
+ 0.3 V  
cc  
0.8  
4
VIL  
-0.3  
V
Inputs  
CIN  
Input Capacitance  
Input High Current (Pull-down)  
pF  
VCC = VIN  
3.456V  
=
AUTO, REF_SEL, FIN_SEL1,  
FIN_SEL0, FEC_SEL1,  
FEC_SEL0, P_SEL2, P_SEL1,  
P_SEL0  
LVCMOS /  
LVTTL  
IIH  
150 µA  
IIL  
R
Input Low Current (Pull-down)  
Internal Pull-down Resistance  
Input High Current (Pull-UP)  
-5  
µA  
kΩ  
Inputs with  
Pull-down  
LVCMOS /  
LVTTL  
50  
50  
pulldown  
VCC = 3.456V  
IN = 0 V  
IIH  
5
µA  
V
NBW  
IIL  
R
Input Low Current (Pull-UP)  
Internal Pull-UP Resistance  
Output High Voltage  
-150  
µA  
kΩ  
Inputs with  
Pull-UP  
pullup  
Differential  
Output  
VOH  
VOL  
VP-P  
VOH  
VOL  
V
- 1.4  
V
V
- 1.0 V  
cc  
cc  
FOUT, nFOUT  
Output Low Voltage  
V
- 2.0  
- 1.7 V  
cc  
cc  
2
0.4  
0.85  
VCC  
0.4  
Peak to Peak Output Voltage  
Output High Voltage  
V
V
V
2.4  
IOH= 1mA  
IOL= 1mA  
LVCMOS  
Outputs  
LOL, REF_ACK  
GND  
Output Low Voltage  
Table 14: DC Characteristics  
Note 1: Biased to Vcc/2, with 50kto Vcc and 50kto ground. See Figure 4, Input Reference Clocks, on pg. 5  
Note 2: Single-ended measurement. See Figure 6, Output Rise and Fall Time, on pg. 12.  
M2080/81/82 Datasheet Rev 0.4  
11 of 14  
Revised 30Jul2004  
Integrated Circuit Systems, Inc. Networking & Communications www.icst.com tel (508) 852-5400  
M2080/81/82, M2085/86/87  
Integrated  
Circuit  
Systems, Inc.  
VCSO FEC PLL WITH  
A
UTO  
SWITCH FOR SONET/OTN  
P r e l i m i n a r y I n f o r m a t i o n  
ELECTRICAL SPECIFICATIONS (CONTINUED)  
AC Characteristics  
Unless stated otherwise, VCC  
=
3.3V +  
5
%,TA = 0 oC to +70 oC (commercial), TA = -40 oC to +85 oC (industrial), FVCSO = FOUT  
to VCC - 2V  
= 622-675MHz,  
LVPECL outputs terminated with 50  
Symbol Parameter  
Min  
Typ  
Max Unit Conditions  
DIF_REF0, nDIF_REF0,  
DIF_REF1, nDIF_REF1  
10  
700  
700  
FIN  
Input Frequency  
MHz  
MHz  
FOUT  
APR  
Output Frequency  
FOUT, nFOUT  
15  
Commercial  
Industrial  
VCSO Absolute  
Pull-Range  
±120  
±50  
±200  
±150  
800  
ppm  
ppm  
KVCO  
RIN  
VCO Gain  
kHz/V  
Wide Bandwidth  
100  
2100  
700  
Internal Loop Resistor  
kΩ  
PLL Loop  
Constants  
1
Narrow Bandwidth  
kΩ  
BWVCSO VCSO Bandwidth  
kHz  
Φn  
Single Side Band  
Phase Noise  
1kHz Offset  
-73  
dBc/Hz  
dBc/Hz  
dBc/Hz  
Fin=19.44 or  
38.88 MHz  
10kHz Offset  
-103  
-126  
Mfin=32 or 16,  
Mfec=Rfec  
@622.08MHz  
PhaseNoise  
and Jitter  
100kHz Offset  
0.25  
0.25  
50  
0.5  
0.5  
55  
J(t)  
Jitter (rms)  
@622.08MHz  
12kHz to 20MHz  
ps  
ps  
%
50kHz to 80MHz  
P = 4, 8, or 32  
2
45  
40  
odc  
Output Duty Cycle  
FOUT, nFOUT  
P = 1  
50  
60  
%
2
200  
450  
500  
tR  
tF  
Output Rise Time  
ps  
20% to 80%  
20% to 80%  
FOUT, nFOUT  
2
200  
450  
500  
Output Fall Time  
ps  
Table 15: AC Characteristics  
Note 1: Parameters needed for PLL Simulator software; see Table 11, Example Values for Loop Filter External Components, on pg. 9.  
Note 2: See Parameter Measurement Information on pg. 12.  
PARAMETER MEASUREMENT INFORMATION  
Output Rise and Fall Time  
Output Duty Cycle  
nFOUT  
FOUT  
80%  
80%  
VP-P  
tPW  
(Output Pulse Width)  
20%  
t
F
20%  
Clock Output  
t
R
tPERIOD  
t
PW  
odc =  
t
PERIOD  
Figure 7: Output Duty Cycle  
Figure 6: Output Rise and Fall Time  
M2080/81/82 M2085/86/87 Datasheet Rev 0.4  
12 of 14  
Revised 30Jul2004  
Integrated Circuit Systems, Inc. Networking & Communications www.icst.com tel (508) 852-5400  
M2080/81/82, M2085/86/87  
Integrated  
Circuit  
Systems, Inc.  
VCSO FEC PLL WITH  
A
UTO  
SWITCH FOR SONET/OTN  
P r e l i m i n a r y I n f o r m a t i o n  
DEVICE PACKAGE - 9 x 9mm CERAMIC LEADLESS CHIP CARRIER  
Mechanical Dimensions:  
Refer to the M208x Series product web page at  
www.icst.com/products/summary/m2080-2087.htm  
for recommended PCB footprint, solder mask,  
furnace profile, and related information.  
Figure 8: Device Package - 9 x 9mm Ceramic Leadless Chip Carrier  
M2080/81/82 Datasheet Rev 0.4  
13 of 14  
Revised 30Jul2004  
Integrated Circuit Systems, Inc. Networking & Communications www.icst.com tel (508) 852-5400  
P r e l i m i n a r y I n f o r m a t i o n  
VCSO FEC PLL WITH  
M2080/81/82, M2085/86/87  
Integrated  
Circuit  
Systems, Inc.  
AUTO  
SWITCH FOR SONET/OTN  
Standard VCSO Output Frequencies (MHz)*  
ORDERING INFORMATION  
622.0800  
625.0000  
627.3296  
644.5313  
666.5143  
669.1281  
669.3120  
669.3266  
669.6429  
670.8386  
672.1600  
690.5692  
Part Numbering Scheme  
Part Number:  
M208x-yz-xxx.xxxx  
Divider Look-up Table Option  
See Table 9, page 4.  
Output type  
1 = LVPECL  
(For CML or LVDS clock output, consult factory)  
Hitless Switching / Phase Build-out Options  
1 = none  
Table 16: Standard VCSO Output Frequencies  
2 = Hitless Switching  
3 = Hitless Switching with Phase Build-out  
Temperature  
0
to +70 o  
C
(commercial)  
I-==- 40 to +85 o  
C (industrial)  
VCSO Frequency (MHz)  
See Table 16, right. Consult ICS for other frequencies.  
Figure 9: Part Numbering Scheme  
Note *: Fout can equal Fvcso divided by: 1, 4, 8, or 32.  
Consult ICS for the availability of other VCSO frequencies.  
Example Part Numbers  
VCSO Frequency (MHz)  
Temperature  
commercial  
industrial  
commercial  
industrial  
Order Part Number (Examples)  
M2081-11-622.0800 or M2082-11-622.0800  
622.0800  
M2081-11  
M2080-11-669.3266 or M2085-11-669.3266  
M2080-11 669.3266 or M2085-11 669.3266  
I622.0800 or M2082-11I622.0800  
669.3266  
I
I
Table 17: Example Part Numbers  
While the information presented herein has been checked for both accuracy and reliability, Integrated Circuit Systems (ICS)  
assumes no responsibility for either its use or for the infringement of any patents or other rights of third parties, which would  
result from its use. No other circuits, patents, or licenses are implied. This product is intended for use in normal commercial  
applications. Any other applications such as those requiring extended temperature range, high reliability, or other extraordinary  
environmental requirements are not recommended without additional processing by ICS. ICS reserves the right to change any  
circuitry or specifications without notice. ICS does not authorize or warrant any ICS product for use in life support devices or  
critical medical instruments.  
M2080/81/82 M2085/86/87 Datasheet Rev 0.4  
14 of 14  
Revised 30Jul2004  
Integrated Circuit Systems, Inc. Networking & Communications www.icst.com tel (508) 852-5400  

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