Si51211 - Silicon Labs

S i 5 1 2 11
T HREE O UTPUTS F ACTORY P R O GRA MM A B LE C LOCK
G ENERATOR
Features
Generates up to 3 CMOS clock  Separate voltage supply pins
outputs from 3 to 200 MHz
VDD = 2.5 to 3.3 V
 Accepts crystal or reference
VDDO= 1.8 to 3.3 V (VDDO ≤ VDD)
clock input
 0.25% to 1.0% Spread Spectrum
3 to 166 MHz reference clock input
(Center Spread)
8 to 48 MHz crystal input
 Low cycle-cycle jitter
 Programmable FSEL, SSEL,
 Programmable output rise and
SSON, PD, and OE input
fall times
functions
 Ultra small 8-pin TDFN package
 Low power dissipation
(1.4 x 1.6 mm)

Applications
Crystal/XO replacement
EMI reduction
 Portable devices
Digital still camera
IP phone
 Smart meter




Ordering Information:
See page 9.
Pin Assignments
Description
8
VDDO
7
SSCLK3
3
6
SSCLK2/REFCLK_D
FSEL/SSEL/SSON/
PD/OE1
4
5
VSS
VDD
1
XOUT
2
Si51211
The factory programmable Si51211 is a low power, small 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 3 outputs up to 200 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. A separate VDDO supply pin supports
clock output at a different voltage level.
XIN/CLKIN
SSCLK1/REFCLK
FSEL/SSEL/SSON/
OE2
Patents pending
Functional Block Diagram
XOUT 2
VDD0 8
VDD 1
4
PLL with
Modulation
Control
XIN/
3
CLKIN
To Pin 7
V-REG
To Core
Programmable
Configuration
Register
To Pin 4 and Pin 6
VSS 5
Preliminary Rev. 0.7 1/12
Buffers,
Dividers,
and
Switch
Matrix
6
SSCLK1/
REFCLK/
0E2/FSEL/
SSEL/SS0N
SSCLK2/
REFCLK_D
0E1/FSEL/
SSEL/SS0N/PD
7 SSCLK3 (VDD0)
Copyright © 2012 by Silicon Laboratories
Si51211
This information applies to a product under development. Its characteristics and specifications are subject to change without notice.
Si51211
2
Preliminary Rev. 0.7
Si51211
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 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .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: 8-Pin TDFN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
5. Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
6. Package Outline: 8-pin TDFN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Contact Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Preliminary Rev. 0.7
3
Si51211
1. Electrical Specifications
Table 1. DC Electrical Specifications
(VDD = 2.5 V ± 5%, or VDD = 3.3 V ± 10%, TA = 0 to 70 oC)
Parameter
Symbol
Test Condition
Min
Typ
Max
Unit
VDD
VDD=3.3 V ±10%
2.97
3.3
3.63
V
VDD=2.5 V ±5%
2.375
2.5
2.625
V
VDDO
VDDO ≤ VDD
1.71
—
3.6
V
Output High Voltage
VOH
IOH= –4 mA,
VDDX=VDD or VDDO
VDDX-0.5
—
—
V
Output Low Voltage
VOL
IOL= 4mA,
—
—
0.3
V
Input High Voltage
VIH
CMOS level
0.7 VDD
—
—
V
Input Low Voltage
VIL
CMOS level
—
—
0.3 VDD
V
Operating Supply Current
IDD
FIN=12 MHz,
SSCLK1=12 MHz,
SSCLK2 =24 MHz, CL=0,
VDD=VDDO=3.3 V
—
6
—
mA
Nominal Output Impedance
ZO
—
30
—

Operating Voltage
RPUP/RPD
Pin 6
—
150k
—

Input Pin Capacitance
CIN
Input Pin Capacitance
—
3
5
pF
Load Capacitance
CL
Clock outputs < 166 MHz
—
—
15
pF
Clock outputs > 166 MHz
—
—
10
pF
Internal Pull-up/Pull-down
Resistor
4
Preliminary Rev. 0.7
Si51211
Table 2. AC Electrical Specifications
(VDD = 2.5 V ± 5%, or VDD = 3.3 V ± 10%, 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
SSCLK1/2/3
3
—
200
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=15 pF, 20 to 80%
—
1
3.0
ns
Output Fall Time
tf
CL=15 pF, 20 to 80%
—
1
3.0
ns
PJ1
SSCLK1/2/3, three clocks running,
VDD=3.3 V, CL=15 pF
—
150*
—
ps
CCJ1
SSCLK1/2/3, three clocks running,
VDD=3.3 V, CL=15 pF
—
100*
—
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 outputs SSCLK1/2 (asynchronous)
—
15
—
ns
Output Disable Time
tOD
Time from OE falling edge to active
at outputs SSCLK1/2 (asynchronous)
—
15
—
ns
Min
Typ
Max
Unit
–0.5
—
4.2
V
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
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
Si51211
2. Design Considerations
2.1. Typical Application Schematic
VDD
10µF
0.1µF
0.1µF
VDD
VDDO
CL1
XOUT
SSCLK3
Si51211
XIN
SSCLK2
CL2
VDD
FSEL
VSS
5K
5K
2.2. Comments and Recommendations
Decoupling Capacitor: A decoupling capacitor of 0.1 μF must be used between VDD and VSS on the pins 1 and
8. 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. In addition, a 10 µF capacitor should be placed between VDD and VSS.
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 Si51211 pin capacitance (4 pF).
Cp is the parasitic capacitance of the PCB traces.
Example: If a crystal with CL=12 pF specification is used and Cp=1 pF (parasitic PCB capacitance on PCB), 19 or 20 pF
external capacitors from pins XIN (pin 2) and XOUT (Pin 3) to VSS are required. Users must verify Cp value.
6
Preliminary Rev. 0.7
Si51211
3. Functional Description
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 three outputs can be programmed as SSCLK or REFCLK. SSCLK output can be synthesized to any value
from 3 to 200 MHz with spread based on valid input frequency. The spread at SSCLK pins can be stopped by the
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 Si51211 can synthesize output frequency up to 200 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 Si51211 pin 4 and 6 can 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 pins can be programmed for different set of frequencies as selected by FSEL.
SSCLK value can be any frequency from 3 to 200 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 a 48 MHz crystal.
Table 4. Example Frequencies
FSEL
(Pin 6)
SSCLK1
(Pin 4)
0
66 MHz, ±1%
1
33 MHz, ±1%
3.6. Power Down (PD) or Output Enable (OE)
The Si51211 pin 6 can be programmed as PD input. Pin 4 and pin 6 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
Si51211
4. Pin Descriptions: 8-Pin TDFN
VDD
1
8
VDDO
XOUT
2
7
SSCLK3
3
6
SSCLK2/REFCLK_D
FSEL/SSEL/SSON/
PD/OE1
4
5
VSS
Si51211
XIN/CLKIN
SSCLK1/REFCLK
FSEL/SSEL/SSON/
OE2
Table 5. Si51211 Pin Descriptions
8
Pin #
Name
Type
Description
1
VDD
2
XOUT
O
Crystal output. Leave this pin unconnected (floating) if an external clock
input is used.
3
XIN/CLKIN
I
External crystal and clock input.
4
SSCLK1/REFCLK/
FSEL/SSEL/SSON/
OE2
I/O
5
VSS
GND
6
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.
7
SSCLK3
O
Programmable SSCLK3 output. The frequency at this pin is synthesized
by internal PLL with or without spread. It is power by VDDO pin (pin 8).
8
VDDO
PWR 2.5 to 3.3 V power supply.
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.
Ground.
PWR 1.8 to 3.3 V output power supply to SSCLK3 (pin 7) VDDO ≤ VDD.
Preliminary Rev. 0.7
Si51211
5. Ordering Information
Part Number
Package Type
Temperature
Si51211-AxxxFM
8-pin TDFN
Commercial, 0 to 70 C
Si51211-AxxxFMR
8-pin TDFN—Tape and Reel
Commercial, 0 to 70 C
Si 51211
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
Si51211
6. Package Outline: 8-pin TDFN


10
Preliminary Rev. 0.7
Si51211
NOTES:
Preliminary Rev. 0.7
11
Si51211
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
support or sustain life, or for any other application in which the failure of the Silicon Laboratories product could create a situation where personal injury or death may occur. Should Buyer purchase or use Silicon Laboratories products for any such unintended or unauthorized application, Buyer shall indemnify and hold Silicon Laboratories harmless against all claims and damages.
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