Preliminary Information
M685
FOUT
GND
nFOU
D
UAL
SAW, S
ELECTABLE
F
REQUENCY
VCSO
G
ENERAL
D
ESCRIPTION
The M685 is a dual SAW, selectable frequency VCSO
frequency source for low-jitter clock
generation. An integrated SAW (surface
acoustic wave) delay line implements the
high-Q VCO (voltage controlled oscillator)
function, which results in low output phase
noise and very low jitter. The M685-01 is available in
a range of center frequencies from 125 to 177 MHz.
The M685-02 provides 500 to 708 MHz. Guaranteed
minimum pull-range of
±120
ppm meets GbE
requirements. (It also fully satisfies
±50
ppm minimum
pull-range specification commonly required.) Industry-
standard Kvco (VCO Gain) provides full replacement
compatibility. The M685 is well suited for phase-locked
loop implementations, clock and data recovery circuits,
and other timing applications in telecom and optical
fiber networking systems (e.g., OC-48).
P
IN
A
SSIGNMENT
(5 x 7.5mm SMT)
VCC
6
5
M685
M680
2
3
(Top View)
VIN
1
Figure 1: Pin Assignment
Sample of Available Output Frequencies
VCSO Center
Frequencies
1
(MHz)
155.5200, 167.3316
156.2500, 161.1328
622.0800, 669.3266
625.0000, 644.5313
Applications
SONET/SDH, SONET/SDH FEC
Gigabit Ethernet, GbE FEC
SONET/SDH, SONET/SDH FEC
Gigabit Ethernet, GbE FEC
F
EATURES
◆
Two integrated SAW devices and selectable output
frequency; supports multi-rate optical interfaces
◆
M685-01 output frequencies from 125 to 177 MHz
M685-02 output frequencies from 500 to 708 MHz
(Specify center frequencies at time of order)
◆
Industry-standard Kvco for full compatibility
◆
Low phase jitter 0.2ps rms typical for the M685-02
(50kHz to 80MHz)
◆
Differential 3.3V LVPECL output
◆
Single 3.3V power supply
◆
Small 5 x 7.5mm SMT (surface mount) package
◆
Pb-free / Compliant to EC RoHS Directive
Table 1: Sample of Available Output Frequencies
Note 1: Specify VCSO center frequencies at time of order
B
LOCK
D
IAGRAM
M685
SAW Delay Line
VCSO
Phase
Shifter
F_SEL
VIN
SAW Delay Line
FOUT
nFOUT
VCSO
Phase
Shifter
F_SEL
Figure 2: Block Diagram
M685 Datasheet Rev 0.7
M685 Dual SAW, Selectable Frequency VCSO
I n t e g r a t e d D e v i c e Te c h n o l o g y, I n c .
●
C o m m u n i c a t i o n M o d u l e s
●
w w w. i d t . c o m
●
t e l ( 5 0 8 ) 8 5 2 - 5 4 0 0
4
Revised 29Jul2009
M685
D
UAL
SAW, S
ELECTABLE
F
REQUENCY
VCSO
Preliminary Information
P
IN
D
ESCRIPTIONS
Number
1
2
3
4
5
6
Name
VIN
F_SEL
GND
FOUT
nFOUT
VCC
I/O
Configuration
Description
Input
Input
Ground
Output
Power
No internal terminator
Internal pull-down resistor
1
Frequency control input.
Frequency select:
Logic
1
selects Frequency 2
.
Logic
0
selects Frequency 1
.
Power supply ground connection.
Clock output pair. Differential LVPECL.
Power supply connection, connect to +
3.3
V.
Table 2: Pin Descriptions
Note 1: See “Frequency Select” in Table 5 (DC Characteristics for M685-01 on pg. 3) and Table 7 (DC Characteristics for M685-02 on pg. 4).
A
BSOLUTE
M
AXIMUM
R
ATINGS1
Symbol Parameter
Rating
Unit
V
I
V
O
V
CC
T
S
Inputs
Outputs
Power Supply Voltage
Storage Temperature
-
0.5
to V
CC
+
0.5
-
0.5
to V
CC
+
0.5
4.6
V
V
V
o
-
55
to +
125
C
Table 3: 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.
R
ECOMMENDED
C
ONDITIONS OF
O
PERATION
Symbol Parameter
Min
2.97
Typ
3.3
25
Max
3.63
Unit
V
CC
T
A
Positive Supply Voltage
Ambient Operating Temperature
V
o
C
-
40
+
85
Table 4: Recommended Conditions of Operation
M685 Datasheet Rev 0.7
2 of 7
Revised 29Jul2009
I n t e g r a t e d D e v i c e Te c h n o l o g y, I n c .
●
C o m m u n i c a t i o n M o d u l e s
●
w w w. i d t . c o m
●
t e l ( 5 0 8 ) 8 5 2 - 5 4 0 0
M685
D
UAL
SAW, S
ELECTABLE
F
REQUENCY
VCSO
Preliminary Information
E
LECTRICAL
S
PECIFICATIONS FOR
M685-01
DC Characteristics for M685-01
Unless stated otherwise, V
CC
= 3.3 Volts + 10%, T
A
= 0 to 85
o
C, VCSO Freq.’s = 155.52, 167.3316MHz, Outputs terminated into 180Ω to ground
Symbol Parameter
Pin
VCC
Min
2.97
Typ
3.3
90
Max
3.63
125
3.3
Unit
Power Supply V
CC
I
CC
Control
Voltage
Frequency
Select
1
V
IN
V
IH
V
IL
I
IH
I
IL
Positive Supply Voltage
Power Supply Current
Input Control Voltage Range
V
IN
Input Impedence
Input High Voltage
Input Low Voltage
Input High Current
Input Low Current
V
mA
V
kΩ
V
V
µA
µA
VIN
0
100
2
V
cc
+
0.3
0.8
-
0.3
F_SEL
5
-1
50
51
V
cc
-
0.98
R
pulldown
Internal Pull-down Resistor
Differential
Outputs
V
OH
V
OL
V
P
-
P
I
OUT
Output High Voltage
Output Low Voltage
Peak to Peak Output Voltage
2
Output Current
FOUT, nFOUT
V
cc
-
1.95
0.450
kΩ
V
cc
-
0.75
V
V
cc
-
1.63
V
0.625
0.85
20
V
P
-
P
mA
Note 1: Internally pulled down to Logic 0 (Frequency 1) if left unselected.
Note 2: Single-ended measurement. See Figure 3, Output Rise and Fall Time, on pg. 5.
Table 5: DC Characteristics for M685-01
AC Characteristics for M685-01
Unless stated otherwise, V
CC
= 3.3 Volts + 10%, T
A
= 0 to 85
o
C, VCSO Freq.’s = 155.52, 167.3316MHz, Outputs terminated into 180Ω to ground
Symbol Parameter
Min
VIN
125
Typ
600
Max
Unit
Notes
Control Voltage V
IN
Output
F
OUT
APR
f
STAB
L
IN
K
VCO
Φ
n
Modulation Bandwidth
kHz
177
Output Center Frequency Range
M685-01
Absolute (Guaranteed) Pull-Range
1
Frequency Stability
Tuning Linearity
VCO Gain
Non-harmonic Spurious
SSB (single sideband)
Phase Noise, offset
from carrier
@
155.52
MHz
100Hz Offset
1kHz Offset
10kHz Offset
100kHz Offset
1MHz Offset
12kHz to 20MHz
50kHz to 80MHz
MHz
ppm
ppm p-p
At any givin V
IN
%
V
IN
=
0.3
to
3.0
V
Best fit straight line
±
120
100
6
@
155.52
MHz
-50
400
-77
-48
-75
-99
-124
-142
0.30
0.18
45
275
275
55
425
425
ppm/V
V
IN
=
0.3
to
3.0
V
dBc
dBc/Hz
dBc/Hz
dBc/Hz
dBc/Hz
dBc/Hz
ps rms
ps rms
%
ps
ps
20
% to
80
%
20
% to
80
%
J(t)
odc
t
R
t
F
Jitter (rms)
@
155.52
MHz
Output Duty Cycle
2
Output Rise Time
2
for
FOUT, nFOUT
Output Fall Time
2
for
FOUT, nFOUT
Note 1: Also fully meets ±50 ppm minimum pull-range specification that is commonly required.
Note 2: See Parameter Measurement Information on pg. 5.
Table 6: AC Characteristics for M685-01
M685 Datasheet Rev 0.7
3 of 7
Revised 29Jul2009
I n t e g r a t e d D e v i c e Te c h n o l o g y, I n c .
●
C o m m u n i c a t i o n M o d u l e s
●
w w w. i d t . c o m
●
t e l ( 5 0 8 ) 8 5 2 - 5 4 0 0
M685
D
UAL
SAW, S
ELECTABLE
F
REQUENCY
VCSO
Preliminary Information
E
LECTRICAL
S
PECIFICATIONS FOR
M685-02
DC Characteristics for M685-02
Unless stated otherwise, V
CC
= 3.3 Volts + 10%, T
A
= 0 to 85
o
C, VCSO Freq.’s = 622.08, 669.3266MHz, Outputs terminated into 180Ω to ground
Symbol Parameter
Pin
VCC
Min
2.97
Typ
3.3
90
Max
3.63
125
3.3
Unit
Power Supply V
CC
I
CC
Control
Voltage
Frequency
Select
1
V
IN
V
IH
V
IL
I
IH
I
IL
Positive Supply Voltage
Power Supply Current
Input Control Voltage Range
V
IN
Input Impedence
Input High Voltage
Input Low Voltage
Input High Current
Input Low Current
V
mA
V
kΩ
V
V
µA
µA
VIN
0
100
2
V
cc
+
0.3
0.8
-
0.3
F_SEL
5
-1
50
51
V
cc
-
0.98
R
pulldown
Internal Pull-down Resistor
Differential
Outputs
V
OH
V
OL
V
P
-
P
I
OUT
Output High Voltage
Output Low Voltage
Peak to Peak Output Voltage
2
Output Current
FOUT, nFOUT
V
cc
-
1.95
0.450
kΩ
V
cc
-
0.75
V
V
cc
-
1.63
V
0.625
0.85
20
V
P
-
P
mA
Note 1: Internally pulled down to Logic 0 (Frequency 1) if left unselected.
Note 2: Single-ended measurement. See Figure 3, Output Rise and Fall Time, on pg. 5.
Table 7: DC Characteristics for M685-02
AC Characteristics for M685-02
Unless stated otherwise, V
CC
= 3.3 Volts + 10%, T
A
= 0 to 85
o
C, VCSO Freq.’s = 622.08, 669.3266MHz, Outputs terminated into 180Ω to ground
Symbol Parameter
Min
VIN
500
Typ
600
Max
Unit
Notes
Control Voltage V
IN
Output
F
OUT
APR
f
STAB
L
IN
K
VCO
Φ
n
Modulation Bandwidth
kHz
708
Output Center Frequency Range
M685-02
Absolute (Guaranteed) Pull-Range
1
Frequency Stability
Tuning Linearity
VCO Gain
Non-harmonic Spurious
SSB (single sideband)
Phase Noise, offset
from carrier
@
622.08
MHz
100Hz Offset
1kHz Offset
10kHz Offset
100kHz Offset
1MHz Offset
12kHz to 20MHz
50kHz to 80MHz
MHz
ppm
ppm p-p
At any givin V
IN
%
V
IN
=
0.3
to
3.0
V
Best fit straight line
±
120
100
6
@
622.08
MHz
-50
400
-77
-42
-72
-102
-127
-146
0.22
0.16
45
275
275
55
400
400
ppm/V
V
IN
=
0.3
to
3.0
V
dBc
dBc/Hz
dBc/Hz
dBc/Hz
dBc/Hz
dBc/Hz
ps rms
ps rms
%
ps
ps
20
% to
80
%
20
% to
80
%
J(t)
odc
t
R
t
F
Jitter (rms)
@
622.08
MHz
Output Duty Cycle
2
Output Rise Time
2
for
FOUT, nFOUT
Output Fall Time
2
for
FOUT, nFOUT
Note 1: Also fully meets ±50 ppm minimum pull-range specification that is commonly required.
Note 2: See Parameter Measurement Information on pg. 5.
Table 8: AC Characteristics for M685-02
M685 Datasheet Rev 0.7
4 of 7
Revised 29Jul2009
I n t e g r a t e d D e v i c e Te c h n o l o g y, I n c .
●
C o m m u n i c a t i o n M o d u l e s
●
w w w. i d t . c o m
●
t e l ( 5 0 8 ) 8 5 2 - 5 4 0 0
M685
D
UAL
SAW, S
ELECTABLE
F
REQUENCY
VCSO
Preliminary Information
P
ARAMETER
M
EASUREMENT
I
NFORMATION
Output Rise and Fall Time
80%
Clock
Outputs
20%
t
R
80%
V
P-P
20%
t
F
FOUT
t
PW
(Output Pulse Width)
t
PERIOD
odc =
t
PW
t
PERIOD
Output Duty Cycle
nFOUT
Figure 3: Output Rise and Fall Time
Figure 4: Output Duty Cycle
D
EVICE
P
ACKAGE
-
5 x 7.5mm SMT (Surface Mount) Package
Mechanical Dimensions:
M685
-02-AA-AH
Dimensions are in mm;
dimensions in [ ] are in inches
Unless otherwise specified, all
dimensions are
±0.13
[0.005]
Figure 5: Device Package - 5 x 7.5mm SMT (Surface Mount) Package
M685 Datasheet Rev 0.7
5 of 7
Revised 29Jul2009
I n t e g r a t e d D e v i c e Te c h n o l o g y, I n c .
●
C o m m u n i c a t i o n M o d u l e s
●
w w w. i d t . c o m
●
t e l ( 5 0 8 ) 8 5 2 - 5 4 0 0
