SL2305

SL2305
Low Jitter and Skew 10 to 140 MHz Zero Delay Buffer (ZDB)
Key Features
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Description
10 to 140 MHz operating frequency range
Low output clock jitter:
- 140 ps-max c-c-j at 66 MHz
Low output-to-output skew: 150 ps-max
Low product-to-product skew: 400 ps-max
3.3 V power supply range
Low power dissipation:
- 14 mA-max at 66MHz
- 26 mA-max at 133 MHz
One input drives 5 outputs organized as 4+1
SpreadThru™ PLL that allows use of SSCG
Standard and High-Drive options
Available in 8-pin SOIC and TSSOP packages
Available in Commercial and Industrial grades
The SL2305 is available with two (2) drive strength versions.
The -1 is the standard-drive version and -1H is the highdrive version.
The SL2305 high-drive version operates up to 140MHz and
the standard drive version -1 operates up to 100.
The SL2305 enter into Power-Down (PD) mode if the input
at CLKIN is DC (0 to VDD). In this power-down state all five
(5) outputs are tri-stated and the PLL is turned off leading to
less than 12μA-max of power supply current draw.
Benefits
Applications
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The SL2305 is a low skew, low jitter and low power Zero
Delay Buffer (ZDB) designed to produce up to five (5) clock
outputs from one (1) reference input clock for high speed
clock distribution applications. The product has an on-chip
PLL which locks to the input clock at CLKIN and receives its
feedback internally from the CLKOUT pin.
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Printers and MFPs
Digital Copiers
PCs and Work Stations
DTV
Routers, Switchers and Servers
Digital Embeded Systems
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Up to five (5) distribution of input clock
Standard and High-Drive levels to control impedance
level, frequency range and EMI
Low jitter and skew
Low power dissipation
Low cost
Block Diagram
PLL
CLKOUT
CLKIN
CLK1
CLK2
CLK3
CLK4
VDD
GND
Rev 0.1 9/13
400 West Cesar Chavez, Austin, TX 78701
Page 1 of 11
1+(512) 416-8500
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www.silabs.com
SL2305
Pin Configuration
CLKIN
1
8
CLKOUT
CLK2
2
7
CLK4
CLK1
3
6
VDD
GND
4
5
CLK3
8-Pin SOIC or TSSOP
Pin Description
Pin
Number
Pin Name
Pin Type
Pin Description
1
CLKIN
Input
2
CLK2
Output
Buffered Clock Output Weak pull-down (250kΩ).
3
CLK1
Output
Buffered Clock Output. Weak pull-down (250kΩ).
4
GND
Power
Power Ground.
5
CLK3
Output
Buffered Clock Output. Weak pull-down (250kΩ).
6
VDD
Power
3.3V Power Supply.
7
CLK4
Output
Buffered Clock Output. Weak pull-down (250kΩ).
8
CLKOUT
Output
Buffered Clock Output, Used for Internal Feedback to PLL Input. Weak pulldown (250kΩ).
Rev 0.1 9/13
Reference Frequency Clock Input. Weak pull-down (250kΩ).
Page 2 of 11
SL2305
General Description
The SL2305 is a low skew, low jitter Zero Delay Buffer with
very low operating power supply current (IDD).
The product includes an on-chip high performance PLL that
locks into the input reference clock and produces five (5)
output clock drivers tracking the input reference clock for
systems requiring clock distribution.
In addition to CLKOUT that is used for internal PLL
feedback, there is a single bank with four (4) outputs,
bringing the number of total available output clocks to five
(5).
Input and output Frequency Range
The input and output frequency range is the same. But, the
frequency range depends on the drive levels and load
capacitance (CL) as given in the below Table 1.
Drive
CL(pF)
Min(MHz)
Max(MHz)
HIGH (-1H)
15
10
140
HIGH (-1H)
30
10
100
STD (-1)
15
10
100
STD (-1)
30
10
66
Table 1. Input/Output Frequency Range
If the input clock frequency is DC (0 to VDD), this is
detected by an input detection circuitry and all five (5) clock
outputs are forced to Hi-Z. The PLL is shutdown to save
power. In this shutdown state, the product draws less than
12μA-max supply current.
SpreadThru™ Feature
If a Spread Spectrum Clock (SSC) were to be used as an
input clock, the SL2305 is designed to pass the modulated
Spread Spectrum Clock (SSC) signal from its CLKIN
(reference) input to the output clocks. The same spread
characteristics at the input are passed through the PLL and
drivers without any degradation in spread percent (%),
spread profile and modulation frequency.
High and Low-Drive Product Options
The SL2305 is offered with High-Drive “-1H” and StandardDrive “-1” options. These drive options enable the users to
control load levels, frequency range and EMI control. Refer
to the AC electrical tables for the details.
Skew and Zero Delay
All outputs should drive the similar load to achieve outputto-output and input-to-output skew specifications given in
the AC electrical tables.
However, Zero delay between input and outputs can be
adjusted by changing the loading of CLKOUT relative to the
other clock outputs since CLKOUT is the feedback to the
PLL.
Power Supply Range (VDD)
The SL2305 is designed to operate from 3.0V (Min) to 3.6V
(Max), complying with VDD=3.3V+/-10% requirement.
An internal on-chip voltage regulator is used to supply PLL
constant power supply of 1.8V, leading to a consistent and
stable PLL electrical performance in terms of skew, jitter
and power dissipation.
Temperature Range and Packages
The SL2305 is offered with commercial temperature range
of 0 to +70°C (C-Grade) and industrial temperature range of
-40 to +85°C (I-Grade).
The SL2305 is available in 8-pin SOIC (150-mil) and 8-pin
TSSOP (173-mil) packages.
SL23EP05
Refer to SL23EP05 for extended frequency operation from
10 to 220MHz and 2.5V to 3.3V power supply operation
range.
Absolute Maximum Ratings
Description
Condition
Min
Max
Unit
Supply voltage, VDD
– 0.5
4.6
V
All Inputs and Outputs
– 0.5
VDD+0.5
V
Ambient Operating Temperature
In operation, C-Grade
0
70
°C
Ambient Operating Temperature
In operation, I-Grade
– 40
85
°C
Storage Temperature
No power is applied
– 65
150
°C
Junction Temperature
In operation, power is applied
–
125
°C
Rev 0.1 9/13
Page 3 of 11
SL2305
Soldering Temperature
–
260
°C
ESD Rating (Human Body Model)
JEDEC22-A114D
-4,000
4,000
V
ESD Rating (Charge Device Model)
JEDEC22-C101C
-1,500
1,500
V
ESD Rating (Machine Model)
JEDEC22-A115D
-250
250
V
Latch-up
125°C
-200
200
mA
Operating Conditions: Unless otherwise stated VDD=3.3V+/-10% and both C and I Grades
Symbol
Description
Condition
Min
Max
Unit
VDD
3.3V Supply Voltage
3.3V+/-10%
3.0
3.6
V
TA
Operating
Temperature(Ambient)
Commercial
0
70
°C
–40
85
°C
Load Capacitance
10 to 140 MHz, -1H high drive
–
15
pF
10 to 100 MHz, -1H high drive
–
30
pF
10 to 100MHz, -1 standard drive
–
15
pF
10 to 66MHz, -1 standard drive
–
30
pF
–
7
pF
0.05
100
ms
CLOAD
Industrial
CIN
Input Capacitance
CLKIN pin
tpu
Power-up Time
Power-up time for all VDDs to reach
minimum VDD voltage (VDD=3.0V).
CLBW
Closed-loop bandwidth
3.3V, (typical)
1.2
MHz
ZOUT
Output Impedance
3.3V (typical), -1H high drive
22
Ω
3.3V (typical), -1 standard drive
32
Ω
Rev 0.1 9/13
Page 4 of 11
SL2305
DC Electrical Specifications: Unless otherwise stated VDD=3.3V+/-10% and both C and I Grades
Symbol
Description
Condition
Min
Max
Unit
3.0
3.6
V
VDD
Supply Voltage
VIL
Input LOW Voltage
CLKIN (Pin-1)
–
0.8
V
VIH
Input HIGH Voltage
CLKIN (Pin-1)
2.0
VDD+0.3
V
IIL
Input LOW Current
CLKIN, 0 < VIN < 0.8V
–
25
µA
IIH
Input HIGH Current
CLKIN, VIN = VDD
–
50
µA
VOL
Output LOW Voltage
(All outputs)
IOL = 8 mA (standard drive)
–
0.4
V
IOL = 12 mA (high drive)
–
0.4
V
Output HIGH Voltage
(All outputs)
IOH = –8 mA (standard drive)
2.4
–
V
IOH = –12 mA (high drive)
2.4
–
V
Power Down Supply Current
CLKIN=0 to VDD
C-Grade, Power-down if CLKIN=0 to
VDD or input is floating
–
12
µA
I-Grade, Power-down if CLKIN=0 to
VDD or input is floating
–
25
µA
VOH
IDDPD
IDD1
Power Supply Current
All Outputs CL=0, 33MHz CLKIN
–
8
mA
IDD2
Power Supply Current
All Outputs CL=0, 66MHz CLKIN
–
14
mA
IDD3
Power Supply Current
All Outputs CL=0, 100MHz CLKIN
–
20
mA
IDD4
Power Supply Current
All Outputs CL=0, 133MHz CLKIN
–
26
mA
RPD
Pull-down Resistors
Pins-1/2/3/5/7/8, 250kΩ-typ
175
325
kΩ
Switching Specifications: Unless otherwise stated VDD=3.3V+/-10% and both C and I Grades
Symbol
Description
Condition
FMAX1
Maximum Frequency [1]
(Input=Output )
All Active PLL Modes
High drive (-1H). All outputs CL=15pF
10
140
MHz
High drive (-1H), All outputs CL=30pF
10
100
MHz
Standard drive, (-1), All outputs CL=15pf
10
100
MHz
Standard drive, (-1), All outputs CL=30pf
10
66
MHz
Input Duty Cycle
Measured at 1.4V, Fout=66MHz,
CL=15pF
30
70
%
OUTDC1
Output Duty Cycle[2]
Measured at 1.4V, Fout≥50MHz,
CL=15pF
40
60
%
OUTDC2
Output Duty Cycle[2]
Measured at 1.4V, Fout≤50MHz,
CL=15pF
45
55
%
tr/f
Rise, Fall Time (3.3V) [2]
(Measured at: 0.8 to 2.0V)
High drive (-1H), CL=10pF
–
1.5
ns
High drive (-1H), CL=30pF
–
1.8
ns
Standard drive (-1), CL=10pF
–
2.2
ns
Standard drive (-1), CL=30pF
–
2.5
ns
INDC
Rev 0.1 9/13
Min
Max
Unit
Page 5 of 11
SL2305
t1
Output-to-Output Skew[2]
(Measured at VDD/2)
All outputs CL=0 or equally loaded, -1 or
-1H drives
–
150
ps
t2
Product-to-Product Skew[2]
(Measured at VDD/2)
All outputs CL=0 or equally loaded, -1 or
-1H drives
–
400
ps
t3
Delay Time, CLKIN Rising
Edge to CLKOUT Rising
Edge[2]
Measured at VDD/2
–220
220
ps
tPLOCK
PLL Lock Time[2]
Time from 90% of VDD to valid clocks on
all the output clocks
–
1.0
ms
CCJ
Cycle-to-cycle Jitter [2]
Fin=Fout=66 MHz, <CL=15pF, -1H drive
–
140
ps
Fin=Fout=66 MHz, <CL=15pF, -1 drive
–
150
ps
Fin=Fout=66 MHz, <CL=30pF, -1H drive
–
160
ps
Fin=Fout=66 MHz, <CL=30pF, -1 drive
–
170
ps
Notes:
1. For the given maximum loading conditions. See CL in Operating Conditions Table.
2. Parameter is guaranteed by design and characterization. Not 100% tested in production.
Rev 0.1 9/13
Page 6 of 11
SL2305
External Components & Design Considerations
Typical Application Schematic
CLKIN
1
8
CLKOUT
CL
VDD
3
6
0.1μF
SL2305
CLK1
CL
7
4
CLK4
CL
GND
Comments and Recommendations
Decoupling Capacitor: A decoupling capacitor of 0.1μF must be used between VDD and VSS on the pins 6 and 4. Place
the capacitor on the component side of the PCB as close to the VDD pin as possible. The PCB trace to the VDD pin and to
the GND via should be kept as short as possible. Do not use vias between the decoupling capacitor and the VDD pin.
Series Termination Resistor: A series termination resistor is recommended if the distance between the outputs and the
load is over 1 ½ inch. The nominal impedance of the Clock outputs are about 30 Ω. Use 20 Ω resistor in series with the
output to terminate 50Ω trace impedance and place 20 Ω resistor as close to the clock outputs as possible.
Zero Delay and Skew Control: All outputs and CLKIN pins should be loaded with the same load to achieve “Zero Delay”
between the CLKIN and the outputs. The CLKOUT pin is connected to CLKIN internally on-chip for internal feedback to
PLL, and sees an additional 2 pF load with respect to the clock pins. For applications requiring zero input/output delay, the
load at the all output pins including the CLKOUT pin must be the same. If any delay adjustment is required, the capacitance
at the CLKOUT pin could be increased or decreased to increase or decrease the delay between clocks and CLKIN.
For minimum pin-to-pin skew, the external load at the clock outputs must be the same.
Rev 0.1 9/13
Page 7 of 11
SL2305
Switching Waveforms
VDD/2
OUTPUT
VDD/2
OUTPUT
t1
Figure 1. Output to Output Skew
VDD/2
Any Output
Part 1 or 2
VDD/2
Any Output
Part 2 or 1
t3
Figure 2. Input- to-Output Skew
VDD/2
INPUT
VDD/2
CLKOUT
t2
Figure 3. Part-to-Part Skew
Rev 0.1 9/13
Page 8 of 11
SL2305
Package Outline and Package Dimensions
8-Pin SOIC Package (150-mil)
5
8
Dimensions are in inches(milimeters).
Top line: (MIN) and Bottom line: (Max)
0.150(3.810)
0.157(3.987
Pin-1 ID
0.230(5.842)
0.244(6.197)
4
1
0.189(4.800)
0.196(4.978)
0.010(0.2540)
X 45°
0.016(0.406)
0.0075(0.190)
0.0098(0.249)
0.061(1.549)
0.068(1.727)
0.004(0.102)
0.050(1.270)
BSC
0.004(0.102)
0.0098(0.249)
Seating plane
0.016(0.406)
0.035(0.889)
0° to 8°
0.0138(0.350)
0.0192(0.487)
Thermal Characteristics
Parameter
Thermal Resistance
Junction to Ambient
Thermal Resistance
Junction to Case
Rev 0.1 9/13
Symbol
Condition
Min
Typ
Max
Unit
θ JA
Still air
-
150
-
°C/W
θ JA
1m/s air flow
-
140
-
°C/W
θ JA
3m/s air flow
-
120
-
°C/W
θ JC
Independent of air flow
-
40
-
°C/W
Page 9 of 11
SL2305
Package Outline and Package Dimensions
8-Pin TSSOP Package (4.4-mm)
8
5
6.250(0.246)
6.500(0.256)
4.300(0.169)
4.500(0.177)
Dimensions are in milimeters (inches)
Top line: (MIN) and Bottom line: (Max)
Pin-1 ID
1
4
2.900(0.114)
3.100(0.122)
1.200(0.047) MAX
0.190(0.007)
0.300(0.012)
0.250(0.010)
BSC
0.050(0.002)
0.150(0.006)
0.800(0.031)
1.050(0.041)
0.076(0.003)
0.650(0.025)
BSC
0.090(0.003)
0.200(0.008)
Gauge
Plane
0 to 8°
Seating Plane
0.500(0.020)
0.750(0.030)
Thermal Characteristics
Parameter
Thermal Resistance
Junction to Ambient
Thermal Resistance
Junction to Case
Rev 0.1 9/13
Symbol
Condition
Min
Typ
Max
Unit
Still air
-
110
-
°C/W
1m/s air flow
-
100
-
°C/W
3m/s air flow
-
80
-
°C/W
Independent of air flow
-
35
-
°C/W
Page 10 of 11
SL2305
Ordering Information *
Ordering Number
Marking
Shipping Package
Package
Temperature
SL2305SC-1
SL2305SC-1
Tube
8-pin SOIC
0 to 70°C
SL2305SC-1T
SL2305SC-1
Tape and Reel
8-pin SOIC
0 to 70°C
SL2305SI-1
SL2305SI-1
Tube
8-pin SOIC
-40 to 85°C
SL2305SI-1T
SL2305SI-1
Tape and Reel
8-pin SOIC
-40 to 85°C
SL2305SC-1H
SL2305SC-1H
Tube
8-pin SOIC
0 to 70°C
SL2305SC-1HT
SL2305SC-1H
Tape and Reel
8-pin SOIC
0 to 70°C
SL2305SI-1H
SL2305SI-1H
Tube
8-pin SOIC
-40 to 85°C
SL2305SI-1HT
SL2305SI-1H
Tape and Reel
8-pin SOIC
-40 to 85°C
SL2305ZC-1
SL2305ZC-1
Tube
8-pin TSSOP
0 to 70°C
SL2305ZC-1T
SL2305ZC-1
Tape and Reel
8-pin TSSOP
0 to 70°C
SL2305ZI-1
SL2305ZI-1
Tube
8-pin TSSOP
-40 to 85°C
SL2305ZI-1T
SL2305ZI-1
Tape and Reel
8-pin TSSOP
-40 to 85°C
SL2305ZC-1H
SL2305ZC-1H
Tube
8-pin TSSOP
0 to 70°C
SL2305ZC-1HT
SL2305ZC-1H
Tape and Reel
8-pin TSSOP
0 to 70°C
SL2305ZI-1H
SL2305ZI-1H
Tube
8-pin TSSOP
-40 to 85°C
SL2305ZI-1HT
SL2305ZI-1H
Tape and Reel
8-pin TSSOP
-40 to 85°C
*Note: The SL2305 products are RoHS compliant.
Rev 0.1 9/13
Page 11 of 11
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