Si51214 - Silicon Labs

Si51214
TWO O UTPUTS F ACTORY P ROGRAMMABLE C L O C K
G ENERATOR
Features
Generates up to 2 CMOS clock  1.8 V voltage supply range
outputs from 3 to 133 MHz
 0.25% to 1.0% Spread Spectrum
(Center Spread)
 Accepts crystal or reference
clock input
 Low cycle-cycle jitter
3 to 166 MHz reference clock input  Programmable output rise and
8 to 48 MHz crystal input
fall times
 Programmable FSEL, SSEL,
 Ultra small 6-pin TDFN package
SSON, PD, and OE input
(1.2 mmx1.4 mm)
functions
 Low power dissipation

Applications
Crystal/XO replacement
 EMI reduction
 Portable devices

Ordering Information:
See page 9.
Digital still camera
 IP phone
 Smart meter

Description
The factory programmable Si51214 is industry’s lowest power, smallest
footprint and frequency flexible programmable clock generator targeting
low power, low cost and high volume consumer and embedded
applications. The device operates from a single crystal or an external
clock source and generates 1 to 2 outputs up to 133 MHz. They are
factory programmed to provide customized output frequencies, control
inputs and ac parameter tuning like output drive strength that are
optimized for customer board condition and application requirements.
Pin Assignments
VDD
1
XIN/CLKIN
2
XOUT
3
6
Si51214
5
4
VSS
SSCLK2/REFCLK_D
FSEL/SSEL/SSON/
PD/OE1
SSCLK1/REFCLK
FSEL/SSEL/SSON/
OE2
Patents pending
Functional Block Diagram
PLL with
Modulation
Control
XIN/
2
CLKIN
XOUT 3
VDD 1
VSS 6
V-REG
To Core
To Pin 4 and
Pin 5
Preliminary Rev. 0.7 1/12
Programmable
Configuration
Register
Buffers,
Dividers,
and
Switch
Matrix
4 SSCLK1/
REFCLK/
0E2/FSEL/
SSEL/SS0N
5 SSCLK2/
REFCLK_D
0E1/FSEL/
SSEL/SS0N/PD
Copyright © 2012 by Silicon Laboratories
Si51214
This information applies to a product under development. Its characteristics and specifications are subject to change without notice.
Si51214
2
Preliminary Rev. 0.7
Si51214
TABLE O F C ONTENTS
Section
Page
1. Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
2. Design Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
2.1. Typical Application Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
2.2. Comments and Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
3. Functional Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
3.1. Input Frequency Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
3.2. Output Frequency Range and Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
3.3. Programmable Modulation Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
3.4. Programmable Spread Percent (%) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
3.5. SSON or Frequency Select (FSEL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
3.6. Power Down (PD) or Output Enable (OE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
4. Pin Descriptions: 6-Pin TDFN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
5. Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
6. Package Outline: 6-pin TDFN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Contact Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Preliminary Rev. 0.7
3
Si51214
1. Electrical Specifications
Table 1. DC Electrical Specifications
(VDD = 1.8 V ±5%, TA = 0 to 70 oC)
Parameter
Symbol
Test Condition
Min
Typ
Max
Unit
Operating Voltage
VDD
VDD=1.8 V ± 5%
1.71
1.8
1.89
V
Output High Voltage
VOH
IOH= –4 mA
VDD-0.5
—
—
V
Output Low Voltage
VOL
IOL= 4 mA
—
—
0.3
V
Input High Voltage
VIH
CMOS Level
0.7VDD
—
—
V
Input Low Voltage
VIL
CMOS Level
0
—
0.3VDD
V
Operating Supply Current
IDD
FIN=12 MHz, SSCLK1
=12 MHz, SSCLK2
=24 MHz, CL=0, VDD=1.8 V
—
3.5
—
mA
Nominal Output Impedance
ZO
—
30
—

RPUP/RPD
Pin 5
—
150k
—

Input Pin Capacitance
CIN
Input pin capacitance
—
3
5
pF
Load Capacitance
CL
Clock outputs
—
—
15
pF
Internal Pull-up/Pull-down
Resistor
4
Preliminary Rev. 0.7
Si51214
Table 2. AC Electrical Specifications
(VDD = 1.8 V ±5%, TA = 0 to 70 oC)
Parameter
Symbol
Condition
Min
Typ
Max
Unit
Input Frequency Range
FIN1
Crystal input
8
—
48
MHz
Input Frequency Range
FIN2
Reference clock Input
3
—
166
MHz
Output Frequency Range
FOUT
SSCLK1/2, CL=15 pF
3
—
133
MHz
Frequency Accuracy
FACC
Configuration dependent
—
0
—
ppm
DCOUT
Measured at VDD/2
45
50
55
%
Input Duty Cycle
DCIN
CLKIN, CLKOUT through PLL
30
50
70
%
Output Rise Time
tr
CL=5 pF, 20 to 80%
—
1
3.0
ns
Output Fall Time
tf
CL=5 pF, 20 to 80%
—
1
3.0
ns
PJ1
SSCLK1/2, two clocks running,
VDD=1.8 V, CL=5 pF
—
160*
—
ps
CCJ1
SSCLK1/2, two clocks running,
VDD=1.8 V, CL=5 pF
—
120*
—
ps
Power-up Time
tPU
Time from 0.9 VDD to valid frequencies at all clock outputs
—
1.2
5.0
ms
Output Enable Time
tOE
Time from OE raising edge to active
at output SSCLK (asynchronous)
—
15
—
ns
Output Disable Time
tOD
Time from OE falling edge to active at
output SSCLK (asynchronous)
—
15
—
ns
Output Duty Cycle
Period Jitter
Cycle-to-Cycle Jitter
*Note: Jitter performance depends on configuration and programming parameters.
Table 3. Absolute Maximum Conditions
Parameter
Symbol
Condition
Min
Typ
Max
Unit
–0.5
—
2.4
V
Main Supply Voltage
VDD
Input Voltage
VIN
Relative to VSS
–0.5
—
VDD+0.5
V
Temperature, Storage
TS
Non-functional
–65
—
150
°C
Temperature, Operating Ambient
TA
Functional, C-Grade
0
—
70
°C
ESD Protection (Human Body Model)
ESDHBM
JEDEC (JESD 22-A114)
–4000
—
4000
V
ESD Protection (Charge Device Model)
ESDCDM
JEDEC (JESD 22-C101)
–1500
—
1500
V
ESD Protection (Machine Model)
ESDMM
JEDEC (JESD 22-A115)
–200
—
200
V
MSL
JEDEC (J-STD-020)
Moisture Sensitivity Level
1
Note: While using multiple power supplies, the Voltage on any input or I/O pin cannot exceed the power pin during power-up.
Power supply sequencing is not required.
Preliminary Rev. 0.7
5
Si51214
2. Design Considerations
2.1. Typical Application Schematic
VDD
10µF
0.1µF
VDD
CL1
XIN
XOUT
VSS
SSCLK3
VDD
Si51214
XOUT
XIN
FSEL
5K
CL2
5K
2.2. Comments and Recommendations
Decoupling Capacitor: A decoupling capacitor of 0.1 μF must be used between VDD and VSS on pin 1. 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
(SSCLK or REFCLK pins) and the load is over 1 ½ inch. The nominal impedance of the SSCLK output is about
30 Ω. Use 20 Ω resistor in series with the output to terminate 50 Ω trace impedance and place 20 Ω resistor as
close to the SSCLK output as possible.
Crystal and Crystal Load: Only use a parallel resonant fundamental AT cut crystal. Do not use higher overtone
crystals. To meet the crystal initial accuracy specification (in ppm) make sure that external crystal load capacitor is
matched to crystal load specification. To determine the value of CL1 and CL2, use the following formula:
C1 = C2 = 2CL – (Cpin + Cp)
Where: CL is load capacitance stated by crystal manufacturer
Cpin is the Si51214 pin capacitance (4 pF).
Cp is the parasitic capacitance of the PCB traces.
Example: If a crystal with CL=18 pF is used and Cp=4 pF, by using the above formula, PCin=PCout=[(18 – (4/2)] x
2 = 32 pF. Programming PCin and PCout to 32 pF assures that this crystal sees an equivalent load of 18 pF and no
other external crystal load capacitor is needed. Deviating from the crystal load specification could cause an
increase in frequency accuracy in ppm.
6
Preliminary Rev. 0.7
Si51214
3. Functional Descriptions
3.1. Input Frequency Range
The input frequency range is from 8.0 to 48.0 MHz for crystals and ceramic resonators. If an external clock is used,
the input frequency range is from 8.0 to 166.0 MHz.
3.2. Output Frequency Range and Outputs
Up to two outputs can be programmed as SSCLK or REFCLK. SSCLK output can be synthesized to any value from
3 to 133 MHz with spread based on valid input frequency. The spread at SSCLK pins can be stopped by SSON
input control pin, If SSON pin is high (VDD), the frequency at SSCLK pin is synthesized to the nominal value of the
input frequency and there is no spread.
REFCLK is the buffered output of the oscillator and is the same frequency as the input frequency without spread.
However, REFCLK_D output is divided by output dividers from 2 to 32. By using only low cost, fundamental mode
crystals, the Si51214 can synthesize output frequency up to 133 MHz, eliminating the need for higher order
crystals (Xtals) and crystal oscillators (XOs). This reduces the cost while improving the system clock accuracy,
performance and reliability.
3.3. Programmable Modulation Frequency
The spread spectrum clock (SSC) modulation default value is 31.5 kHz. The higher values of up to 62 kHz can also
be programmed. Less than 30 kHz modulation frequency is not recommended to stay out of the range audio
frequency bandwidth since this frequency could be detected as a noise by the audio receivers within the vicinity.
3.4. Programmable Spread Percent (%)
The spread percent (%) value is programmable from ±0.25% to ±1% (center spread) for all SSCLK frequencies. It
is possible to program smaller or larger non-standard values of spread percentage. Contact Silicon Labs if these
non-standard spread percent values are required in the application.
3.5. SSON or Frequency Select (FSEL)
The Si51214 pin4 and 5can be programmed as either SSON to enable or disable the programmed spread percent
value or as frequency select (FSEL). If SSON is used, when this pin is pulled high (VDD), the spread is stopped
and the frequency is the nominal value without spread. If low (GND), the frequency is the nominal value with the
spread.
If FSEL function is used, the output pin can be programmed for different set of frequencies as selected by FSEL.
SSCLK value can be any frequency from 3 to 133 MHz, but the spread % is the same percent value. REFCLK is
the same frequency as the input reference clock and the REFCLK_D input clock is divided by 2 to 32 without
spread. The set of frequencies in Table 4 is given as an example, using 48 MHz crystal.
Table 4. Example Frequencies
FSEL
(Pin 4)
SSCLK1
(Pin 5)
0
66 MHz, ±1%
1
33 MHz, ±1%
3.6. Power Down (PD) or Output Enable (OE)
The Si51214 pin 5 can be programmed as PD input. Pin 4 and pin 5 can be programmed as OE input. PD turns off
both PLL and output buffers whereas OE only disables the output buffers to Hi-Z.
Preliminary Rev. 0.7
7
Si51214
4. Pin Descriptions: 6-Pin TDFN
VDD
1
XIN/CLKIN
2
XOUT
3
6
Si51214
5
4
VSS
SSCLK2/REFCLK_D
FSEL/SSEL/
SSON/PD/OE1
SSCLK1/REFCLK
FSEL/SSEL/
SSON/OE2
Table 5. Si51214 6-Pin Descriptions
8
Pin #
Name
Type
Description
1
VDD
2
XIN/CLKIN
I
External crystal and clock input.
3
XOUT
O
Crystal output. Leave this pin unconnected (floating) if an external clock
input is used.
4
SSCLK1/REFCLK/
FSEL/SSEL/SSON/
OE2
I/O
Programmable SSCLK1 or REFCLK output or MultiFunction control
input. The frequency at this pin is synthesized by internal PLL if programmed as SSCLK1 with or without spread. If programmed as REFCLK, output clock is buffered output of crystal or reference clock input. If
programmed as MultiFunction control input, it can be OE, FSEL, SSEL
and SSON.
5
SSCLK2/REFCLK_D/
OE1/FSEL/SSEL/
SSON/PD
I/O
Programmable SSCLK2 or REFCLK_D output or MultiFunction control
input. The frequency at this pin is synthesized by internal PLL if programmed as SSCLK2 with or without spread. If programmed as
REFCLK_D, output clock is buffered output of crystal or reference clock
input divided by 2 to 32. If programmed as MultiFunction control input, it
can be OE, PD, FSEL, SSEL and SSON.
6
VSS
GND
PWR 1.8 V power supply.
Ground.
Preliminary Rev. 0.7
Si51214
5. Ordering Information
Part Number
Package Type
Temperature
Si51214-AxxxFM
6-pin TDFN
Commercial, 0 to 70 C
Si51214-AxxxFMR
6-pin TDFN—Tape and Reel
Commercial, 0 to 70 C
Si 51214
SiSi512xx
51210 programmable Clock
Generator Product Family
FMR
AXXX
Operating Temp Range
:
F = 0 to + 70° C
M = TDFN, ROHS 6 , Pb -free
R = Tape & Reel
( blank) = Tubes
A = Product Revision A
2nd Option Code= XXX
A three character code will be assigned for each unique configuration
.
Device starts operation upon powerup
.
Preliminary Rev. 0.7
9
Si51214
1.20±0.05
1.40±0.05
0.75±0.05
0.00-0.05
0.20±0.05
PIN 1 AREA
0.20± 0.025
NOTE
10
0.40± 0.05
6. Package Outline: 6-pin TDFN
Preliminary Rev. 0.7
0.40±0.05
4
6
3
1
Pin 1 Corner
Si51214
NOTES:
Preliminary Rev. 0.7
11
Si51214
CONTACT INFORMATION
Silicon Laboratories Inc.
400 West Cesar Chavez
Austin, TX 78701
Tel: 1+(512) 416-8500
Fax: 1+(512) 416-9669
Toll Free: 1+(877) 444-3032
Please visit the Silicon Labs Technical Support web page:
https://www.silabs.com/support/pages/contacttechnicalsupport.aspx
and register to submit a technical support request.
The information in this document is believed to be accurate in all respects at the time of publication but is subject to change without notice.
Silicon Laboratories assumes no responsibility for errors and omissions, and disclaims responsibility for any consequences resulting from
the use of information included herein. Additionally, Silicon Laboratories assumes no responsibility for the functioning of undescribed features
or parameters. Silicon Laboratories reserves the right to make changes without further notice. Silicon Laboratories makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does Silicon Laboratories assume any liability
arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation consequential or incidental damages. Silicon Laboratories products are not designed, intended, or authorized for use in applications intended to
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Silicon Laboratories and Silicon Labs are trademarks of Silicon Laboratories Inc.
Other products or brand names mentioned herein are trademarks or registered trademarks of their respective holders.
12
Preliminary Rev. 0.7