Si554
R
EVISION
D
Q
UAD
F
R E Q U E N C Y
V
O L TAG E
- C
O N T R O L L E D
C
RYSTAL
O
SCILLATOR
(VCXO) 10 MH
Z TO
1 . 4 G H
Z
Features
Available with any-rate output
frequencies from 10–945 MHz and
selected frequencies to 1.4 GHz
Four selectable output frequencies
3rd generation DSPLL
®
with superior
jitter performance
3x better frequency stability than
SAW-based oscillators
Internal fixed crystal frequency
ensures high reliability and low
aging
Available CMOS, LVPECL,
LVDS, and CML outputs
3.3, 2.5, and 1.8 V supply options
Industry-standard 5 x 7 mm
package and pinout
Pb-free/RoHS-compliant
Si5602
Applications
SONET/SDH
xDSL
10 GbE LAN / WAN
Ordering Information:
Low jitter clock generation
Optical modules
Clock and data recovery
See page 10.
Description
The Si554 quad-frequency VCXO utilizes Silicon Laboratories’ advanced
DSPLL
®
circuitry to provide a very low jitter clock for all output frequencies.
The Si554 is available with any-rate output frequency from 10 to 945 MHz
and selected frequencies to 1400 MHz. Unlike traditional VCXOs, where a
different crystal is required for each output frequency, the Si554 uses one
fixed crystal frequency to provide a wide range of output frequencies. This
IC-based approach allows the crystal resonator to provide exceptional
frequency stability and reliability. In addition, DSPLL clock synthesis
provides superior supply noise rejection, simplifying the task of generating
low jitter clocks in noisy environments typically found in communication
systems. The Si554 IC-based VCXO is factory-configurable for a wide
variety of user specifications including frequency, supply voltage, output
format, tuning slope, and temperature stability. Specific configurations are
factory-programmed at time of shipment, thereby eliminating the long lead
times associated with custom oscillators.
Pin Assignments:
See page 9.
(Top View)
FS[1]
7
V
C
1
2
3
8
FS[0]
6
5
4
V
DD
OE
GND
CLK–
CLK+
Functional Block Diagram
V
DD
CLK- CLK+
FS1
Fixed
Frequency XO
Any-rate
10–1400 MHz
DSPLL
®
Clock Synthesis
FS0
ADC
V
c
OE
GND
Rev. 1.2 6/18
Copyright © 2018 by Silicon Laboratories
Si554
Si554
1. Electrical Specifications
Table 1. Recommended Operating Conditions
Parameter
Supply Voltage
1
V
DD
Supply Current
I
DD
Symbol
Test Condition
3.3 V option
2.5 V option
1.8 V option
Output enabled
LVPECL
CML
LVDS
CMOS
Tristate mode
Output Enable (OE)
and Frequency Select FS[1:0]
2
Operating Temperature Range
T
A
V
IH
V
IL
Min
2.97
2.25
1.71
—
—
—
—
—
0.75 x V
DD
—
–40
Typ
3.3
2.5
1.8
120
108
99
90
60
—
—
—
Max
3.63
2.75
1.89
130
117
108
98
75
—
0.5
85
Units
V
V
V
mA
mA
V
V
ºC
Notes:
1.
Selectable parameter specified by part number. See Section 3. "Ordering Information" on page 10 for further details.
2.
OE and FS[1:0] pins include a 17 k resistor to VDD.
Table 2. V
C
Control Voltage Input
Parameter
Control Voltage Tuning Slope
1,2,3
K
V
Symbol
Test Condition
10 to 90% of V
DD
Min
—
Typ
33
45
90
135
180
356
±1
±5
10.0
—
V
DD
/2
Max
—
Units
ppm/V
Control Voltage Linearity
4
Modulation Bandwidth
V
C
Input Impedance
Nominal Control Voltage
Control Voltage Tuning Range
L
VC
BW
Z
VC
V
CNOM
V
C
BSL
Incremental
–5
–10
9.3
500
+5
+10
10.7
—
—
V
DD
%
%
kHz
k
V
V
@ f
O
—
0
Notes:
1.
Positive slope; selectable option by part number. See Section 3. "Ordering Information" on page 10.
2.
For best jitter and phase noise performance, always choose the smallest K
V
that meets the application’s minimum APR
requirements. See “AN266: VCXO Tuning Slope (K
V
), Stability, and Absolute Pull Range (APR)” for more information.
3.
K
V
variation is ±10% of typical values.
4.
BSL determined from deviation from best straight line fit with V
C
ranging from 10 to 90% of V
DD
. Incremental slope
determined with V
C
ranging from 10 to 90% of V
DD
.
2
Rev. 1.2
Si554
Table 3. CLK± Output Frequency Characteristics
Parameter
Nominal Frequency
1,2,3
Temperature Stability
1,4
Symbol
f
O
Test Condition
LVDS/CML/LVPECL
CMOS
T
A
= –40 to +85 °C
Min
10
10
–20
–50
–100
±12
Frequency drift over first year.
Frequency drift over 15 year life.
Power up Time
5
Settling Time After FS[1:0]
Change
t
OSC
Typ
—
—
—
—
—
—
—
—
—
—
Max
945
160
+20
+50
+100
±375
±3
±10
10
20
Units
MHz
MHz
ppm
ppm
ppm
ms
ms
Absolute Pull Range
1,4
Aging
APR
—
—
—
—
t
FRQ
Both FS[1] and FS[0] changing
simultaneously
Notes:
1.
See Section 3. "Ordering Information" on page 10 for further details.
2.
Specified at time of order by part number. Also available in frequencies from 970 to 1134 MHz and 1213 to 1417 MHz.
3.
Nominal output frequency set by V
CNOM
= V
DD
/2.
4.
Selectable parameter specified by part number.
5.
Time from power up or tristate mode to f
O
(to within ±1 ppm of f
O
).
Table 4. CLK± Output Levels and Symmetry
Parameter
LVPECL Output Option
1
Symbol
V
O
V
OD
V
SE
Test Condition
mid-level
swing (diff)
swing (single-ended)
mid-level
swing (diff)
Min
V
DD
– 1.42
1.1
0.55
1.125
0.5
Typ
—
Max
V
DD
– 1.25
1.9
0.95
1.275
0.9
Units
V
V
PP
V
PP
V
V
PP
—
—
1.20
0.7
LVDS Output Option
2
V
O
V
OD
CML Output Option
2
V
O
V
OD
2.5/3.3 V option mid-level
1.8 V option mid-level
2.5/3.3 V option swing (diff)
1.8 V option swing (diff)
I
OH
= 32 mA
I
OL
= 32 mA
—
—
1.10
0.35
0.8 x V
DD
V
DD
– 1.30
V
DD
– 0.36
1.50
0.425
—
—
—
1
—
—
—
1.90
0.50
V
DD
V
V
V
PP
V
PP
V
CMOS Output Option
3
Rise/Fall time (20/80%)
Symmetry (duty cycle)
V
OH
V
OL
t
R,
t
F
—
—
—
45
0.4
350
—
55
LVPECL/LVDS/CML
CMOS with C
L
= 15 pF
LVPECL:
(diff)
LVDS:
CMOS:
V
DD
– 1.3 V
1.25 V (diff)
V
DD
/2
ps
ns
%
SYM
Notes:
1.
50
to V
DD
– 2.0 V.
2.
R
term
= 100
(differential).
3.
C
L
= 15 pF
Rev. 1.2
3
Si554
Table 5. CLK± Output Phase Jitter
Parameter
Phase Jitter (RMS)
1,2,3
for F
OUT
> 500 MHz
Symbol
Test Condition
Kv = 33 ppm/V
12 kHz to 20 MHz (OC-48)
50 kHz to 80 MHz (OC-192)
Kv = 45 ppm/V
12 kHz to 20 MHz (OC-48)
50 kHz to 80 MHz (OC-192)
Kv = 90 ppm/V
12 kHz to 20 MHz (OC-48)
50 kHz to 80 MHz (OC-192)
Kv = 135 ppm/V
12 kHz to 20 MHz (OC-48)
50 kHz to 80 MHz (OC-192)
Kv = 180 ppm/V
12 kHz to 20 MHz (OC-48)
50 kHz to 80 MHz (OC-192)
Kv = 356 ppm/V
12 kHz to 20 MHz (OC-48)
50 kHz to 80 MHz (OC-192)
Min
—
—
—
—
—
—
—
—
—
—
—
—
Typ
0.26
0.26
0.27
0.26
0.32
0.26
0.40
0.27
0.49
0.28
0.87
0.33
Max
—
—
—
—
—
—
—
—
—
—
—
—
Units
ps
J
ps
ps
ps
ps
ps
Notes:
1.
Refer to AN255, AN256, and AN266 for further information.
2.
For best jitter and phase noise performance, always choose the smallest K
V
that meets the application’s minimum APR
requirements. See “AN266: VCXO Tuning Slope (K
V
), Stability, and Absolute Pull Range (APR)” for more information.
3.
See “AN255: Replacing 622 MHz VCSO devices with the Si550 VCXO” for comparison highlighting power supply
rejection (PSR) advantage of Si55x versus SAW-based solutions.
4.
Max jitter for LVPECL output with V
C
=1.65V, V
DD
=3.3V, 155.52 MHz.
5.
Max offset frequencies: 80 MHz for F
OUT
> 250 MHz, 20 MHz for 50 MHz < F
OUT
<250 MHz,
2 MHz for 10 MHz < F
OUT
<50 MHz.
4
Rev. 1.2
Si554
Table 5. CLK± Output Phase Jitter (Continued)
Parameter
Phase Jitter (RMS)
1,2,3,4,5
for F
OUT
of 125 to 500 MHz
Symbol
Test Condition
Kv = 33 ppm/V
12 kHz to 20 MHz (OC-48)
50 kHz to 80 MHz (OC-192)
Kv = 45 ppm/V
12 kHz to 20 MHz (OC-48)
50 kHz to 80 MHz (OC-192)
Kv = 90 ppm/V
12 kHz to 20 MHz (OC-48)
50 kHz to 80 MHz (OC-192)
Kv = 135 ppm/V
12 kHz to 20 MHz (OC-48)
50 kHz to 80 MHz (OC-192)
Kv = 180 ppm/V
12 kHz to 20 MHz (OC-48)
50 kHz to 80 MHz (OC-192)
Kv = 356 ppm/V
12 kHz to 20 MHz (OC-48)
50 kHz to 80 MHz (OC-192)
Min
—
—
—
—
—
—
—
—
—
—
—
—
Typ
0.37
0.33
0.37
0.33
0.43
0.34
0.50
0.34
0.59
0.35
1.00
0.39
Max
—
—
0.4
—
—
—
—
—
—
—
—
—
Units
ps
J
ps
ps
ps
ps
ps
Notes:
1.
Refer to AN255, AN256, and AN266 for further information.
2.
For best jitter and phase noise performance, always choose the smallest K
V
that meets the application’s minimum APR
requirements. See “AN266: VCXO Tuning Slope (K
V
), Stability, and Absolute Pull Range (APR)” for more information.
3.
See “AN255: Replacing 622 MHz VCSO devices with the Si550 VCXO” for comparison highlighting power supply
rejection (PSR) advantage of Si55x versus SAW-based solutions.
4.
Max jitter for LVPECL output with V
C
=1.65V, V
DD
=3.3V, 155.52 MHz.
5.
Max offset frequencies: 80 MHz for F
OUT
> 250 MHz, 20 MHz for 50 MHz < F
OUT
<250 MHz,
2 MHz for 10 MHz < F
OUT
<50 MHz.
Rev. 1.2
5
