Cirrus CS2300P-CZZ Fractional-n clock multiplier with internal lco Datasheet

CS2300-OTP
Fractional-N Clock Multiplier with Internal LCO
Features
General Description
 Clock Multiplier / Jitter Reduction
The CS2300-OTP is an extremely versatile system
clocking device that utilizes a programmable phase lock
loop. The CS2300-OTP is based on a hybrid analogdigital PLL architecture comprised of a unique combination of a Delta-Sigma Fractional-N Frequency
Synthesizer and a Digital PLL. This architecture allows
for generation of a low-jitter clock relative to an external
noisy synchronization clock with frequencies as low as
50 Hz. The CS2300-OTP has many configuration options which are set once prior to runtime. At runtime
there are three hardware configuration pins available for
mode and feature selection.
–
Generates a Low Jitter 6 - 75 MHz Clock
from a Jittery 50 Hz to 30 MHz Clock
Source
 Internal LCO Reference Clock
 Highly Accurate PLL Multiplication Factor
–
Maximum Error Less Than 1 PPM in HighResolution Mode
 One-Time Programmability
–
–
Configurable Hardware Control Pins
Configurable Auxiliary Output
 Minimal Board Space Required
–
No External Analog Loop-filter
Components
The CS2300-OTP is available in a 10-pin MSOP package in Commercial (-10°C to +70°C) grade. Customer
development kits are also available for custom device
prototyping, small production programming, and device
evaluation. Please see “Ordering Information” on
page 25 for complete details.
3.3 V
Frequency Reference
Hardware Control
PLL Output
Hardware Configuration
Lock Indicator
LCO
Fractional-N
Frequency Synthesizer
Auxiliary
Output
6 to 75 MHz
PLL Output
N
50 Hz to 30 MHz
Frequency Reference
Output to Input
Clock Ratio
http://www.cirrus.com
Digital PLL & Fractional
N Logic
Copyright  Cirrus Logic, Inc. 2009
(All Rights Reserved)
AUG '09
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TABLE OF CONTENTS
1. PIN DESCRIPTION ................................................................................................................................. 4
2. TYPICAL CONNECTION DIAGRAM ..................................................................................................... 5
3. CHARACTERISTICS AND SPECIFICATIONS ...................................................................................... 6
RECOMMENDED OPERATING CONDITIONS .................................................................................... 6
ABSOLUTE MAXIMUM RATINGS ........................................................................................................ 6
DC ELECTRICAL CHARACTERISTICS ................................................................................................ 6
AC ELECTRICAL CHARACTERISTICS ................................................................................................ 7
PLL PERFORMANCE PLOTS ............................................................................................................... 8
4. ARCHITECTURE OVERVIEW ............................................................................................................... 9
4.1 Delta-Sigma Fractional-N Frequency Synthesizer ........................................................................... 9
4.2 Hybrid Analog-Digital Phase Locked Loop ...................................................................................... 9
5. APPLICATIONS ................................................................................................................................... 11
5.1 One Time Programmability ............................................................................................................ 11
5.2 Timing Reference Clock ................................................................................................................. 11
5.3 Frequency Reference Clock Input, CLK_IN ................................................................................... 11
5.3.1 Adjusting the Minimum Loop Bandwidth for CLK_IN ............................................................ 11
5.4 Output to Input Frequency Ratio Configuration ............................................................................. 13
5.4.1 User Defined Ratio (RUD) ..................................................................................................... 13
5.4.2 Ratio Modifier (R-Mod) .......................................................................................................... 13
5.4.3 Effective Ratio (REFF) .......................................................................................................... 13
5.4.4 Ratio Configuration Summary ............................................................................................... 14
5.5 PLL Clock Output ........................................................................................................................... 15
5.6 Auxiliary Output .............................................................................................................................. 16
5.7 Mode Pin Functionality ................................................................................................................... 16
5.7.1 M1 and M0 Mode Pin Functionality ....................................................................................... 16
5.7.2 M2 Mode Pin Functionality .................................................................................................... 17
5.7.2.1 M2 Configured as Output Disable .............................................................................. 17
5.7.2.2 M2 Configured as R-Mod Enable .............................................................................. 17
5.7.2.3 M2 Configured as AuxOutSrc Override ..................................................................... 17
5.8 Clock Output Stability Considerations ............................................................................................ 18
5.8.1 Output Switching ................................................................................................................... 18
5.8.2 PLL Unlock Conditions .......................................................................................................... 18
5.9 Required Power Up Sequencing for Programmed Devices ........................................................... 18
6. PARAMETER DESCRIPTIONS ........................................................................................................... 19
6.1 Modal Configuration Sets ............................................................................................................... 19
6.1.1 R-Mod Selection (RModSel[1:0]) ........................................................................................... 19
6.1.2 Auxiliary Output Source Selection (AuxOutSrc[1:0]) ............................................................. 20
6.2 Ratio 0 - 3 ...................................................................................................................................... 20
6.3 Global Configuration Parameters ................................................................................................... 20
6.3.1 AUX PLL Lock Output Configuration (AuxLockCfg) .............................................................. 20
6.3.2 Enable PLL Clock Output on Unlock (ClkOutUnl) ................................................................. 20
6.3.3 Low-Frequency Ratio Configuration (LFRatioCfg) ................................................................ 20
6.3.4 M2 Pin Configuration (M2Config[2:0]) ................................................................................... 21
6.3.5 Clock Input Bandwidth (ClkIn_BW[2:0]) ................................................................................ 21
7. CALCULATING THE USER DEFINED RATIO .................................................................................... 22
7.1 High Resolution 12.20 Format ....................................................................................................... 22
7.2 High Multiplication 20.12 Format ................................................................................................... 22
8. PROGRAMMING INFORMATION ........................................................................................................ 23
9. PACKAGE DIMENSIONS .................................................................................................................... 24
THERMAL CHARACTERISTICS ......................................................................................................... 24
10. ORDERING INFORMATION .............................................................................................................. 25
11. REVISION HISTORY .......................................................................................................................... 26
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LIST OF FIGURES
Figure 1. Typical Connection Diagram ........................................................................................................ 5
Figure 2. CLK_IN Sinusoidal Jitter Tolerance ............................................................................................. 8
Figure 3. CLK_IN Sinusoidal Jitter Transfer ................................................................................................ 8
Figure 4. CLK_IN Random Jitter Rejection and Tolerance ......................................................................... 8
Figure 5. Delta-Sigma Fractional-N Frequency Synthesizer ....................................................................... 9
Figure 6. Hybrid Analog-Digital PLL .......................................................................................................... 10
Figure 7. External Component Requirements for LCO ............................................................................. 11
Figure 8. Low bandwidth and new clock domain ...................................................................................... 12
Figure 9. High bandwidth with CLK_IN domain re-use ............................................................................. 12
Figure 10. Ratio Feature Summary ........................................................................................................... 14
Figure 11. PLL Clock Output Options ....................................................................................................... 15
Figure 12. Auxiliary Output Selection ........................................................................................................ 16
Figure 13. M2 Mapping Options ................................................................................................................ 17
Figure 14. Parameter Configuration Sets .................................................................................................. 19
LIST OF TABLES
Table 1. Modal and Global Configuration .................................................................................................. 11
Table 2. Ratio Modifier .............................................................................................................................. 13
Table 3. Example 12.20 R-Values ............................................................................................................ 22
Table 4. Example 20.12 R-Values ............................................................................................................ 22
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1. PIN DESCRIPTION
VD
1
10
M0
GND
2
9
M1
CLK_OUT
3
8
M2
AUX_OUT
4
7
FILTN
CLK_IN
5
6
FILTP
Pin Name
#
Pin Description
VD
1
Digital Power (Input) - Positive power supply for the digital and analog sections.
GND
2
Ground (Input) - Ground reference.
CLK_OUT
3
PLL Clock Output (Output) - PLL clock output.
AUX_OUT
4
Auxiliary Output (Output) - This pin outputs a buffered version of one of the input or output clocks,
or a status signal, depending on configuration.
CLK_IN
5
Frequency Reference Clock Input (Input) - Clock input for the Digital PLL frequency reference.
FILTP
FILTN
6
7
LCO Filter Connections (Input/Output) - These pins provide external supply filtering for the LCO.
M2
8
Mode Select (Input) - M2 is a configurable mode selection pin.
M1
9
Mode Select (Input) - M1 is a configurable mode selection pin.
M0
10 Mode Select (Input) - M0 is a configurable mode selection pin.
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2. TYPICAL CONNECTION DIAGRAM
0.1 µF
1 µF
+3.3 V
VD
M2
System Microcontroller
M1
M0
CS2300-OTP
Frequency Reference
CLK_IN
0.1 µF
FILTP
CLK_OUT
To circuitry which requires
a low-jitter clock
AUX_OUT
To other circuitry or
Microcontroller
FILTN
GND
Figure 1. Typical Connection Diagram
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3. CHARACTERISTICS AND SPECIFICATIONS
RECOMMENDED OPERATING CONDITIONS
GND = 0 V; all voltages with respect to ground. (Note 1)
Parameters
Symbol
Min
Typ
Max
Units
(Note 2)
VD
3.1
3.3
3.5
V
Commercial Grade
TAC
-10
-
+70
°C
DC Power Supply
Ambient Operating Temperature (Power Applied)
Notes: 1. Device functionality is not guaranteed or implied outside of these limits. Operation outside of these limits
may adversely affect device reliability.
2. CLK_IN must not be applied when these conditions are not met, including during power up. See section
5.9 on page 18 for required power up procedure.
ABSOLUTE MAXIMUM RATINGS
GND = 0 V; all voltages with respect to ground.
Parameters
Symbol
Min
Max
Units
DC Power Supply
VD
-0.3
6.0
V
Input Current
IIN
-
±10
mA
Digital Input Voltage (Note 3)
VIN
-0.3
VD + 0.4
V
Ambient Operating Temperature (Power Applied)
TA
-55
125
°C
Storage Temperature
Tstg
-65
150
°C
WARNING: Operation at or beyond these limits may result in permanent damage to the device.
Notes: 3. The maximum over/under voltage is limited by the input current except on the power supply pin.
DC ELECTRICAL CHARACTERISTICS
Test Conditions (unless otherwise specified): VD = 3.1 V to 3.5 V; TA = -10°C to +70°C (Commercial Grade).
Parameters
Symbol
Min
Typ
Max
Units
Power Supply Current - Unloaded
(Note 4)
ID
-
18
23
mA
Power Dissipation - Unloaded
(Note 4)
PD
-
59
76
mW
Input Leakage Current
IIN
-
-
±10
µA
Input Capacitance
IC
-
8
-
pF
High-Level Input Voltage
VIH
70%
-
-
VD
Low-Level Input Voltage
VIL
-
-
30%
VD
High-Level Output Voltage (IOH = -1.2 mA)
VOH
80%
-
-
VD
Low-Level Output Voltage (IOH = 1.2 mA)
VOL
-
-
20%
VD
Notes: 4. To calculate the additional current consumption due to loading (per output pin), multiply clock output
frequency by load capacitance and power supply voltage.
For example, fCLK_OUT (49.152 MHz) * CL(15 pF) * VD (3.3 V) = 2.4 mA of additional current due to
these loading conditions on CLK_OUT.
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AC ELECTRICAL CHARACTERISTICS
Test Conditions (unless otherwise specified): VD = 3.1 V to 3.5 V; TA = -10°C to +70°C (Commercial Grade);
CL = 15 pF.
Parameters
Symbol
Clock Input Frequency
fCLK_IN
Clock Input Pulse Width
pwCLK_IN
PLL Clock Output Frequency
fCLK_OUT
Conditions
fCLK_IN < 175 kHz
fCLK_IN > 175 kHz
Min
Typ
Max
Units
50 Hz
-
30
MHz
140
10
-
-
ns
ns
6
-
75
MHz
PLL Clock Output Duty Cycle
tOD
Measured at VD/2
45
50
55
%
Clock Output Rise Time
tOR
20% to 80% of VD
-
1.7
3.0
ns
Clock Output Fall Time
tOF
80% to 20% of VD
-
1.7
3.0
ns
Period Jitter
tJIT
(Note 5)
-
35
-
ps rms
Base Band Jitter (100 Hz to 40 kHz)
(Notes 5, 6)
-
50
-
ps rms
Wide Band JItter (100 Hz Corner)
(Notes 5, 7)
-
150
-
ps rms
fCLK_IN < 200 kHz
fCLK_IN > 200 kHz
-
100
1
200
3
UI
ms
PLL Lock Time - CLK_IN (Note 8)
tLC
Notes: 5. fCLK_OUT = 24.576 MHz; Sample size = 10,000 points; AuxOutSrc[1:0] = 11.
6. In accordance with AES-12id-2006 section 3.4.2. Measurements are Time Interval Error taken with 3rd
order 100 Hz to 40 kHz bandpass filter.
7. In accordance with AES-12id-2006 section 3.4.1. Measurements are Time Interval Error taken with 3rd
order 100 Hz Highpass filter.
8. 1 UI (unit interval) corresponds to tCLK_IN or 1/fCLK_IN.
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PLL PERFORMANCE PLOTS
Test Conditions (unless otherwise specified): VD = 3.3 V; TA = 25 °C (Commercial Grade); CL = 15 pF;
fCLK_OUT = 12.288 MHz; fCLK_IN = 12.288 MHz; Sample size = 10,000 points; Base Band Jitter (100 Hz to 40 kHz);
AuxOutSrc[1:0] = 11.
10,000
10
1 Hz Bandwidth
128 Hz Bandwidth
1 Hz Bandwidth
128 Hz Bandwidth
0
-10
Jitter Transfer (dB)
Max Input Jitter Level (usec)
1,000
100
10
-20
-30
-40
1
-50
0.1
1
10
100
1,000
-60
10,000
1
10
Input Jitter Frequency (Hz)
100
1000
10000
Input Jitter Frequency (Hz)
Figure 2. CLK_IN Sinusoidal Jitter Tolerance
Figure 3. CLK_IN Sinusoidal Jitter Transfer
Samples size = 2.5M points; Base Band Jitter (10Hz to 40kHz).
Samples size = 2.5M points; Base Band Jitter (10Hz to 40kHz).
1000
1 Hz Bandwidth
128 Hz Bandwidth
Output Jitter Level (nsec)
100
Unlock
10
1
Unlock
0.1
0.01
0.01
0.1
1
10
100
1000
Input Jitter Level (nsec)
Figure 4. CLK_IN Random Jitter Rejection and Tolerance
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4. ARCHITECTURE OVERVIEW
4.1
Delta-Sigma Fractional-N Frequency Synthesizer
The core of the CS2300 is a Delta-Sigma Fractional-N Frequency Synthesizer which has very high-resolution for Input/Output clock ratios, low phase noise, very wide range of output frequencies and the ability to
quickly tune to a new frequency. In very simplistic terms, the Fractional-N Frequency Synthesizer multiplies
the LC Oscillator (LCO) by the value of N to generate the PLL output clock. The desired output to input clock
ratio is the value of N that is applied to the delta-sigma modulator (see Figure 5).
The analog PLL based frequency synthesizer uses a low-jitter timing reference clock, the LCO, as a time
and phase reference for the internal voltage controlled oscillator (VCO). The phase comparator compares
the fractional-N divided clock with the original timing reference and generates a control signal. The control
signal is filtered by the internal loop filter to generate the VCO’s control voltage which sets its output frequency. The delta-sigma modulator modulates the loop integer divide ratio to get the desired fractional ratio
between the reference clock and the VCO output (thus the duty cycle of the modulator sets the fractional
value). This allows the design to be optimized for very fast lock times for a wide range of output frequencies
without the need for external filter components.
LC Oscillator
Phase
Comparator
Internal
Loop Filter
Voltage Controlled
Oscillator
PLL Output
Fractional-N
Divider
Delta-Sigma
Modulator
N
Figure 5. Delta-Sigma Fractional-N Frequency Synthesizer
4.2
Hybrid Analog-Digital Phase Locked Loop
The addition of the Digital PLL and Fractional-N Logic (shown in Figure 6) to the Fractional-N Frequency
Synthesizer creates the Hybrid Analog-Digital Phase Locked Loop with many advantages over classical analog PLL techniques. These advantages include the ability to operate over extremely wide frequency ranges
without the need to change external loop filter components while maintaining impressive jitter reduction performance. In the Hybrid architecture, the Digital PLL calculates the ratio of the PLL output clock to the frequency reference and compares that to the desired ratio. The digital logic generates a value of N which is
then applied to the Fractional-N frequency synthesizer to generate the desired PLL output frequency. Notice
that the frequency and phase of the LCO does not affect the output of the PLL since the digital control loop
will correct for the PLL output. A major advantage of the Digital PLL is the ease with which the loop filter
bandwidth can be altered. The PLL bandwidth is set to a wide-bandwidth mode to quickly achieve lock and
then reduced for optimal jitter rejection.
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CS2300-OTP
Delta-Sigma Fractional-N Frequency Synthesizer
LCO
Phase
Comparator
Internal
Loop Filter
Voltage Controlled
Oscillator
PLL Output
Fractional-N
Divider
Delta-Sigma
Modulator
Digital PLL and Fractional-N Logic
N
Digital Filter
Frequency Reference
Clock
Frequency
Comparator for
Frac-N Generation
Output to Input Ratio for Hybrid mode
Figure 6. Hybrid Analog-Digital PLL
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5. APPLICATIONS
5.1
One Time Programmability
The one time programmable (OTP) circuitry in the CS2300-OTP allows for pre-configuration of the device
prior to use in a system. There are two types of parameters that are used for device pre-configuration: modal
and global. The modal parameters are features which, when grouped together, create a modal configuration
set (see Figure 14 on page 19). Up to four modal configuration sets can be permanently stored and then
dynamically selected using the M[1:0] mode select pins (see Table 1). The global parameters are the remaining configuration settings which do not change with the mode select pins. The modal and global parameters can be pre-set at the factory or user programmed using the customer development kit, CDK2000;
Please see “Programming Information” on page 23 for more details.
Parameter Type
M[1:0] pins = 00
M[1:0] pins = 01
M[1:0] pins = 10
M[1:0] pins = 11
Modal
Configuration Set 0
Ratio 0
Configuration Set 1
Ratio 1
Configuration Set 2
Ratio 2
Configuration Set 3
Ratio 3
Global
Configuration settings set once for all modes.
Table 1. Modal and Global Configuration
5.2
Timing Reference Clock
The internal LC oscillator is used to generate the timing reference clock. A single 0.1 µF cap must be connected between the FILTP and FILTN pins and FILTN must be connected to ground as shown in Figure 7.
FILTN
FILTP
0.1 µF
Figure 7. External Component Requirements for LCO
5.3
Frequency Reference Clock Input, CLK_IN
The frequency reference clock input (CLK_IN) is used by the Digital PLL and Fractional-N Logic block to
dynamically generate a fractional-N value for the Frequency Synthesizer (see “Hybrid Analog-Digital PLL”
on page 10). The Digital PLL first compares the CLK_IN frequency to the PLL output. The Fractional-N logic
block then translates the desired ratio based off of CLK_IN to one based off of the internal LCO. This allows
the low-jitter internal LCO to be used as the clock which the Frequency Synthesizer multiplies while maintaining synchronicity with the frequency reference clock through the Digital PLL. The allowable frequency
range for CLK_IN is found in the “AC Electrical Characteristics” on page 7.
5.3.1
Adjusting the Minimum Loop Bandwidth for CLK_IN
The CS2300 allows the minimum loop bandwidth of the Digital PLL to be adjusted between 1 Hz and
128 Hz using the ClkIn_BW[2:0] global parameter. The minimum loop bandwidth of the Digital PLL directly affects the jitter transfer function; specifically, jitter frequencies below the loop bandwidth corner are
passed from the PLL input directly to the PLL output without attenuation. In some applications it is desirable to have a very low minimum loop bandwidth to reject very low jitter frequencies, commonly referred
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CS2300-OTP
to as wander. In others it may be preferable to remove only higher frequency jitter, allowing the input wander to pass through the PLL without attenuation.
Typically, applications in which the PLL_OUT signal creates a new clock domain from which all other system clocks and associated data are derived will benefit from the maximum jitter and wander rejection of
the lowest PLL bandwidth setting. See Figure 8.
PLL
BW = 1 Hz
CLK_IN
Wander > 1 Hz
PLL_OUT
Wander and Jitter > 1 Hz Rejected
MCLK
Jitter
MCLK
Subclocks generated
from new clock domain.
or
LRCK
LRCK
SCLK
SCLK
D0
SDATA
D1
SDATA
D0
D1
Figure 8. Low bandwidth and new clock domain
Systems in which some clocks and data are derived from the PLL_OUT signal while other clocks and data
are derived from the CLK_IN signal will often require phase alignment of all the clocks and data in the
system. See Figure 9. If there is substantial wander on the CLK_IN signal in these applications, it may be
necessary to increase the minimum loop bandwidth allowing this wander to pass through to the CLK_OUT
signal in order to maintain phase alignment. For these applications, it is advised to experiment with the
loop bandwidth settings and choose the lowest bandwidth setting that does not produce system timing
errors due to wandering between the clocks and data synchronous to the CLK_IN domain and those synchronous to the PLL_OUT domain.
PLL
BW = 128 Hz
CLK_IN
Wander < 128 Hz
PLL_OUT
Jitter > 128 Hz Rejected
Wander < 128 Hz Passed to Output
MCLK
Jitter
MCLK
or
Subclocks and data re-used
from previous clock domain.
LRCK
LRCK
SCLK
SCLK
SDATA
D0
D1
SDATA
D0
D1
Figure 9. High bandwidth with CLK_IN domain re-use
While acquiring lock, the digital loop bandwidth is automatically set to a large value. Once lock is
achieved, the digital loop bandwidth will settle to the minimum value selected by the ClkIn_BW[2:0] parameter.
Referenced Control
Parameter Definition
ClkIn_BW[2:0] .......................“Clock Input Bandwidth (ClkIn_BW[2:0])” on page 21
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5.4
Output to Input Frequency Ratio Configuration
5.4.1
User Defined Ratio (RUD)
The User Defined Ratio, RUD, is a 32-bit un-signed fixed-point number which determines the basis for the
desired input to output clock ratio. Up to four different ratios, Ratio0-3, can be stored in the CS2300’s one
time programmable memory. Selection between the four ratios is achieved by the M[1:0] mode select
pins. The 32-bit RUD can be expressed in either a high resolution (12.20) or high multiplication (20.12)
format selectable by the LFRatioCfg global parameter.
The RUD for high resolution (12.20) format is encoded with 12 MSBs representing the integer binary portion with the remaining 20 LSBs representing the fractional binary portion. The maximum multiplication
factor is approximately 4096 with a resolution of 0.954 PPM in this configuration. See “Calculating the
User Defined Ratio” on page 22 for more information.
The RUD for high multiplication (20.12) format is encoded with 20 MSBs representing the integer binary
portion with the remaining 12 LSBs representing the fractional binary portion. In this configuration, the
maximum multiplication factor is approximately 1,048,575 with a resolution of 244 PPM. It is recommended that the 12.20 High-Resolution format be utilized whenever the desired ratio is less than 4096 since
the output frequency accuracy of the PLL is directly proportional to the accuracy of the timing reference
clock and the resolution of the RUD.
Referenced Control
Parameter Definition
Ratio 0-3................................“Ratio 0 - 3” on page 20
LFRatioCfg ............................“Low-Frequency Ratio Configuration (LFRatioCfg)” on page 20
M[1:0] ....................................“M1 and M0 Mode Pin Functionality” on page 16
5.4.2
Ratio Modifier (R-Mod)
The Ratio Modifier is used to internally multiply/divide the currently addressed RUD (Ratio0-3 stored in the
register space remain unchanged). The available options for R-Mod are summarized in Table 2 on
page 13. R-Mod is enabled via the M2 pin in conjunction with the appropriate setting of the M2Config[2:0]
global parameter (see Section 5.7.2 on page 17).
RModSel[1:0]
R Modifier
00
0.5
01
0.25
10
0.125
11
0.0625
Table 2. Ratio Modifier
Referenced Control
Parameter Definition
Ratio 0-3................................“Ratio 0 - 3” on page 20
RModSel[1:0] ........................“R-Mod Selection (RModSel[1:0])” section on page 19
M2Config[2:0]........................“M2 Pin Configuration (M2Config[2:0])” on page 21
5.4.3
Effective Ratio (REFF)
The Effective Ratio (REFF) is an internal calculation comprised of RUD and the appropriate modifiers, as
previously described. REFF is calculated as follows:
REFF = RUD • R-Mod
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Ratio modifiers which would produce an overflow or truncation of REFF should not be used. In all cases,
the maximum and minimum allowable values for REFF are dictated by the frequency limits for both the
input and output clocks as shown in the “AC Electrical Characteristics” on page 7.
Selection of the user defined ratio from the four stored ratios is made by using the M[1:0] pins.
Referenced Control
Parameter Definition
M[1:0] pins.............................“M1 and M0 Mode Pin Functionality” on page 16
5.4.4
Ratio Configuration Summary
The RUD is the user defined ratio for which up to four different values (Ratio0-3) can be stored in the one
time programmable memory. The M[1:0] pins then select the user defined ratio to be used as well as the
modal configuration set. The resolution/format for the RUD is selectable. R-Mod is applied accordingly.
The user defined ratio, ratio modifier, and automatic ratio modifier make up the effective ratio REFF, the
final calculation used to determine the output to input clock ratio. The conceptual diagram in Figure 10
summarizes the features involved in the calculation of the ratio values used to generate the fractional-N
value which controls the Frequency Synthesizer. The subscript ‘4’ indicates the modal parameters.
LCO
Effective Ratio REFF
M2 pin
M[1:0] pins
User Defined Ratio RUD
Ratio 0
Ratio 1
Ratio 2
Frequency
Synthesizer
RModSel[1:0]4
PLL Output
Ratio Format
12.20
20.12
Ratio
Modifier
Digital PLL &
Fractional N Logic
Dynamic Ratio, ‘N’
Ratio 3
LFRatioCfg
Frequency Reference Clock
(CLK_IN)
Figure 10. Ratio Feature Summary
Referenced Control
Parameter Definition
Ratio 0-3................................“Ratio 0 - 3” on page 20
M[1:0] pins.............................“M1 and M0 Mode Pin Functionality” on page 16
LFRatioCfg ............................“Low-Frequency Ratio Configuration (LFRatioCfg)” on page 20
RModSel[1:0] ........................“R-Mod Selection (RModSel[1:0])” section on page 19
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5.5
PLL Clock Output
The PLL clock output pin (CLK_OUT) provides a buffered version of the output of the frequency synthesizer.
The driver can be set to high-impedance with the M2 pin when the M2Config[1:0] global parameter is set to
either 000 or 010. The output from the PLL automatically drives a static low condition while the PLL is unlocked (when the clock may be unreliable). This feature can be disabled by setting the ClkOutUnl global
parameter, however the state CLK_OUT may then be unreliable during an unlock condition.
ClkOutUnl
PLL Locked/Unlocked
0
0
2:1 Mux
M2 pin with
M2Config[1:0] = 000, 010
0
1
2:1 Mux
PLL Output
PLL Clock Output
PLLClkOut
PLL Clock Output Pin
(CLK_OUT)
1
Figure 11. PLL Clock Output Options
Referenced Control
Parameter Definition
ClkOutUnl..............................“Enable PLL Clock Output on Unlock (ClkOutUnl)” on page 20
ClkOutDis ..............................“M2 Configured as Output Disable” on page 17
M2Config[2:0]........................“M2 Pin Configuration (M2Config[2:0])” on page 21
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5.6
Auxiliary Output
The auxiliary output pin (AUX_OUT) can be mapped, as shown in Figure 12, to one of three signals: input
clock (CLK_IN), additional PLL clock output (CLK_OUT), or a PLL lock indicator (Lock). The mux is controlled via the AuxOutSrc[1:0] modal parameter. If AUX_OUT is set to Lock, the AuxLockCfg global parameter is then used to control the output driver type and polarity of the LOCK signal (see section 6.3.1 on
page 20). If AUX_OUT is set to CLK_OUT, the phase of the PLL Clock Output signal on AUX_OUT may
differ from the CLK_OUT pin. The driver for the pin can be set to high-impedance using the M2 pin when
the M2Config[1:0] global parameter is set to either 001 or 010.
AuxOutSrc[1:0]
M2 pin with
M2Config[1:0] = 001, 010
Frequency Reference Clock
(CLK_IN)
PLL Clock Output
(PLLClkOut)
Auxiliary Output Pin
(AUX_OUT)
3:1 Mux
PLL Lock/Unlock Indication
(Lock)
AuxLockCfg
Figure 12. Auxiliary Output Selection
Referenced Control
Parameter Definition
AuxOutSrc[1:0]......................“Auxiliary Output Source Selection (AuxOutSrc[1:0])” on page 20
AuxOutDis .............................“M2 Configured as Output Disable” on page 17
AuxLockCfg...........................“AUX PLL Lock Output Configuration (AuxLockCfg)” section on page 20
M2Config[2:0]........................“M2 Pin Configuration (M2Config[2:0])” on page 21
5.7
5.7.1
Mode Pin Functionality
M1 and M0 Mode Pin Functionality
M[1:0] determine the functional mode of the device and select both the default User Defined Ratio and
the set of modal parameters. The modal parameters are RModSel[1:0], and AuxOutSrc[1:0]. By modifying
one or more of the modal parameters between the 4 sets, different functional configurations can be
achieved. However, global parameters are fixed and the same value will be applied to each functional
configuration. Figure 14 on page 19 provides a summary of all parameters used by the device.
16
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CS2300-OTP
5.7.2
M2 Mode Pin Functionality
M2 usage is mapped to one of the optional special functions via the M2Config[2:0] global parameter. Depending on what M2 is mapped to, it will either act as an output enable/disable pin or override certain modal parameters. Figure 13 summarizes the available options and the following sections will describe each
option in more detail.
M2Config[2:0] global parameter
000
Disable CLK_OUT pin
001
Disable AUX_OUT pin
010
Disable CLK_OUT and AUX_OUT pins
011
RModSel[1:0] Modal Parameter Enable
100
Reserved
101
Reserved
110
Reserved
111
Force AuxOutSel[1:0] = 10 (PLL Clock Out)
M2 pin
Figure 13. M2 Mapping Options
5.7.2.1
M2 Configured as Output Disable
If M2Config[2:0] is set to either ‘000’, ‘001’, or ‘010’, M2 becomes an output disable pin for one or
both output pins. If M2 is driven ‘low’, the corresponding output(s) will be enabled, if M2 is driven
‘high’, the corresponding output(s) will be disabled.
5.7.2.2
M2 Configured as R-Mod Enable
If M2Config[2:0] is set to ‘011’, M2 becomes the R-Mod enable pin. It should be noted that M2 is
the only way to enable R-Mod. Even though the RModSel[1:0] modal parameter can be set arbitrarily for each configuration set, it will not take effect unless enabled via M2. If M2 is driven ‘low’,
R-Mod will be disabled, if M2 is driven ‘high’ R-Mod will be enabled.
5.7.2.3
M2 Configured as AuxOutSrc Override
If M2Config[2:0] is set to ‘111’, M2 when driven ‘high’ will override the AuxOutSrc[1:0] modal parameter and force the AUX_OUT source to PLL Clock Output. When M2 is driven ‘low’, AUX_OUT
will function according to AuxOutSrc[1:0].
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17
CS2300-OTP
5.8
Clock Output Stability Considerations
5.8.1
Output Switching
The CS2300-OTP is designed such that re-configuration of the clock routing functions do not result in a
partial clock period on any of the active outputs (CLK_OUT and/or AUX_OUT). In particular, enabling or
disabling an output, and the automatic disabling of the output(s) during unlock will not cause a runt or partial clock period.
The following exceptions/limitations exist:
•
Enabling/disabling AUX_OUT when AuxOutSrc[1:0] = 11 (unlock indicator).
•
Switching AuxOutSrc[1:0] to or from 01 (CLK_IN) and to or from 11 (unlock indicator)
(Transitions between AuxOutSrc[1:0] = [00,10] will not produce a glitch).
When any of these exceptions occur, a partial clock period on the output may result.
5.8.2
PLL Unlock Conditions
Certain changes to the clock inputs and mode pins can cause the PLL to lose lock which will affect the
presence of a clock signal on CLK_OUT. The following outlines which conditions cause the PLL to go unlocked:
5.9
18
•
Any change in the state of the M1 and M0 pins will cause the PLL to temporarily lose lock as the new
setting takes affect.
•
Changes made to the state of the M2 when the M2Config[2:0] global parameter is set to 011, 100, 101,
or 110 can cause the PLL to temporarily lose lock as the new setting takes affect.
•
Discontinuities on the Frequency Reference Clock, CLK_IN.
•
Gradual changes in CLK_IN frequency greater than ±30% from the starting frequency.
•
Step changes in CLK_IN frequency.
Required Power Up Sequencing for Programmed Devices
•
Apply power. All input pins should be held in a static logic hi or lo state until the ‘DC Power Supply’ specification in the “Recommended Operating Conditions” table on page 6 are met.
•
Apply input clock.
•
For CDK programmed devices, toggle the state of the M0, M1, or both pins at least 3 times to initialize
the device. This must be done after the power supply is stable and before normal operation is expected.
Note: This operation is not required for factory programmed devices.
•
After the specified PLL lock time on page 7 has passed, the device will output the desired clock as configured by the M0-M2 pins.
DS844F1
CS2300-OTP
6. PARAMETER DESCRIPTIONS
As mentioned in Section 5.1 on page 11, there are two different kinds of parameter configuration sets, Modal and
Global. These configuration sets, shown in Figure 14, can be programmed in the field using the CDK2000 or preprogrammed at the factory. Please see “Programming Information” on page 23 for more details.
M[1:0] pins
Modal Configuration Set #0
Ratio 0
RModSel[1:0]
AuxOutSrc[1:0]
00
RModSel[1:0]
AuxOutSrc[1:0]
01
RModSel[1:0]
AuxOutSrc[1:0]
10
RModSel[1:0]
AuxOutSrc[1:0]
11
Ratio 1
Modal Configuration Set #2
Ratio 2
Modal Configuration Set #3
Ratio 3
Digital/PLL Core
Modal Configuration Set #1
Global Configuration Set
AuxLockCfg
ClkOutUnl
LFRatioCfg
M2Config[2:0]
ClkIn_BW[2:0]
Figure 14. Parameter Configuration Sets
6.1
Modal Configuration Sets
There are four instances of each of these configuration parameters. Selection between the four stored sets
is made using the M[1:0] pins.
6.1.1
R-Mod Selection (RModSel[1:0])
Selects the R-Mod value, which is used as a factor in determining the PLL’s Fractional N.
RModSel[1:0]
R-Mod Selection
00
Right-shift R-value by 1 (÷ 2).
01
Right-shift R-value by 2 (÷ 4).
10
Right-shift R-value by 3 (÷ 8).
11
Right-shift R-value by 4 (÷ 16).
Application:
“Ratio Modifier (R-Mod)” on page 13
Note: This parameter does not take affect unless M2 pin is high and the M2Config[2:0] global parameter is set to ‘011’.
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19
CS2300-OTP
6.1.2
Auxiliary Output Source Selection (AuxOutSrc[1:0])
Selects the source of the AUX_OUT signal.
AuxOutSrc[1:0]
Auxiliary Output Source
00
Reserved.
01
CLK_IN.
10
CLK_OUT.
11
PLL Lock Status Indicator.
Application:
“Auxiliary Output” on page 16
Note: When set to 11, the AuxLockCfg global parameter sets the polarity and driver type (“AUX PLL
Lock Output Configuration (AuxLockCfg)” on page 20).
6.2
Ratio 0 - 3
The four 32-bit User Defined Ratios are stored in the CS2300’s one time programmable memory. See “Output to Input Frequency Ratio Configuration” on page 13 and “Calculating the User Defined Ratio” on
page 22 for more details.
6.3
6.3.1
Global Configuration Parameters
AUX PLL Lock Output Configuration (AuxLockCfg)
When the AUX_OUT pin is configured as a lock indicator (AuxOutSrc[1:0] modal parameter = ‘11’), this
global parameter configures the AUX_OUT driver to either push-pull or open drain. It also determines the
polarity of the lock signal. If AUX_OUT is configured as a clock output, the state of this parameter is disregarded.
AuxLockCfg
AUX_OUT Driver Configuration
0
Push-Pull, Active High (output ‘high’ for unlocked condition, ‘low’ for locked condition).
1
Open Drain, Active Low (output ‘low’ for unlocked condition, high-Z for locked condition).
Application:
“Auxiliary Output” on page 16
Note: AUX_OUT is an unlock indicator, signalling an error condition when the PLL is unlocked. Therefore, the pin polarity is defined relative to the unlock condition.
6.3.2
Enable PLL Clock Output on Unlock (ClkOutUnl)
Defines the state of the PLL output during the PLL unlock condition.
6.3.3
ClkOutUnl
Clock Output Enable Status
0
Clock outputs are driven ‘low’ when PLL is unlocked.
1
Clock outputs are always enabled (results in unpredictable output when PLL is unlocked).
Application:
“PLL Clock Output” on page 15
Low-Frequency Ratio Configuration (LFRatioCfg)
Determines how to interpret the currently indexed 32-bit User Defined Ratio .
20
LFRatioCfg
Ratio Bit Encoding Interpretation
0
20.12 - High Multiplier.
1
12.20 - High Accuracy.
Application:
“User Defined Ratio (RUD)” on page 13
DS844F1
CS2300-OTP
6.3.4
M2 Pin Configuration (M2Config[2:0])
Controls which special function is mapped to the M2 pin.
6.3.5
M2Config[2:0]
M2 pin function
000
Disable CLK_OUT pin.
001
Disable AUX_OUT pin.
010
Disable CLK_OUT and AUX_OUT.
011
RModSel[1:0] Modal Parameter Enable.
100
Reserved.
101
Reserved.
110
Reserved.
111
Force AuxOutSrc[1:0] = 10 (PLL Clock Out).
Application:
“M2 Mode Pin Functionality” on page 17
Clock Input Bandwidth (ClkIn_BW[2:0])
Sets the minimum loop bandwidth when locked to CLK_IN.
DS844F1
ClkIn_BW[2:0]
Minimum Loop Bandwidth
000
1 Hz
001
2 Hz
010
4 Hz
011
8 Hz
100
16 Hz
101
32 Hz
110
64 Hz
111
128 Hz
Application:
“Adjusting the Minimum Loop Bandwidth for CLK_IN” on page 11
21
CS2300-OTP
7. CALCULATING THE USER DEFINED RATIO
Note:
The software for use with the evaluation kit has built in tools to aid in calculating and converting the User
Defined Ratio. This section is for those who would like to know more about how the User Defined Ratio is
calculated and stored.
Most calculators do not interpret the fixed point binary representation which the CS2300-OTP uses to define the
output to input clock ratio (see Section 5.4.1 on page 13); However, with a simple conversion we can use these tools
to generate a binary or hex value for Ratio0-3 to be stored in one time programmable memory. Please see “Programming Information” on page 23 for more details on programming.
7.1
High Resolution 12.20 Format
To calculate the User Defined Ratio (RUD) to store in the register(s), divide the desired output clock frequency by the given input clock (CLK_IN). Then multiply the desired ratio by the scaling factor of 220 to get the
scaled decimal representation; then use the decimal to binary/hex conversion function on a calculator and
write to the register. A few examples have been provided in Table 3.
Scaled Decimal
Representation =
(output clock/input clock) • 220
Hex Representation of
Binary RUD
12.288 MHz/10 MHz=1.2288
1288490
00 13 A9 2A
11.2896 MHz/44.1 kHz=256
268435456
10 00 00 00
Desired Output to Input Clock Ratio
(output clock/input clock)
Table 3. Example 12.20 R-Values
7.2
High Multiplication 20.12 Format
To calculate the User Defined Ratio (RUD) to store in the register(s), divide the desired output clock frequency by the given input clock (CLK_IN). Then multiply the desired ratio by the scaling factor of 212 to get the
scaled decimal representation; then use the decimal to binary/hex conversion function on a calculator and
write to the register. A few examples have been provided in Table 4.
Desired Output to Input Clock Ratio
(output clock/input clock)
Scaled Decimal
Representation =
(output clock/input clock) • 212
Hex Representation of
Binary RUD
12.288 MHz/60 Hz=204,800
838860800
32 00 00 00
11.2896 MHz/59.97 Hz =188254.127...
771088904
2D F5 E2 08
Table 4. Example 20.12 R-Values
22
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CS2300-OTP
8. PROGRAMMING INFORMATION
Field programming of the CS2300-OTP is achieved using the hardware and software tools included with the
CDK2000. The software tools can be downloaded from www.cirrus.com for evaluation prior to ordering a CDK. The
CDK2000 is designed with built-in features to ease the process of programming small quantities of devices for prototype and small production builds. In addition to its field programming capabilities, the CDK2000 can also be used
for the complete evaluation of programmed CS2300-OTP devices.
The CS2300-OTP can also be factory programmed for large quantity orders. When ordering factory programmed
devices, the CDK should first be used to program and evaluate the desired configuration. When evaluation is complete, the CS2000 Configuration Wizard is used to generate a file containing all device configuration information;
this file is conveyed to Cirrus Logic as a complete specification for the factory programming configuration. Please
contact your local Cirrus Logic sales representative for more information regarding factory programmed parts.
See the CDK2000 datasheet, available at www.cirrus.com, for detailed information on the use of the CDK2000 programming and evaluation tools.
Below is a form which represents the information required for programming a device (noted in gray). The “Parameter
Descriptions” section beginning on page 19 describes the functions of each parameter. This form may be used either for personal notation for device configuration or it can be filled out and given to a Cirrus representative in conjunction with the programming file from the CDK2000 as an additional check. The User Defined Ratio may be filled
out in decimal or it may be entered as hex as outlined in “Calculating the User Defined Ratio” on page 22. For all
other parameters mark a ‘0’ or ‘1’ below the parameter name.
OTP Modal and Global Configuration Parameters Form
Modal Configuration Set #0
Ratio 0 (dec)
Ratio 0 (hex) __ __ : __ __ : __ __ : __ __
RModSel1 RModSel0 AuxOutSrc1 AuxOutSrc0
Modal Configuration Set #1
Ratio 1 (dec)
Ratio 1 (hex) __ __ : __ __ : __ __ : __ __
RModSel1 RModSel0 AuxOutSrc1 AuxOutSrc0
Modal Configuration Set #2
Ratio 2 (dec)
Ratio 2 (hex) __ __ : __ __ : __ __ : __ __
RModSel1 RModSel0 AuxOutSrc1 AuxOutSrc0
Modal Configuration Set #3
Ratio 3 (dec)
Ratio 3 (hex) __ __ : __ __ : __ __ : __ __
RModSel1 RModSel0 AuxOutSrc1 AuxOutSrc0
Global Configuration Set
AuxLockCfg ClkOutUnl
ClkIn_BW2
DS844F1
ClkIn_BW1
LFRatioCfg
M2Cfg2
M2Cfg1
M2Cfg0
ClkIn_BW0
23
CS2300-OTP
9. PACKAGE DIMENSIONS
10L MSOP (3 mm BODY) PACKAGE DRAWING (Note 1)
N
D
E11
c
E
A2
A
∝
e
b
A1
SIDE VIEW
1 2 3
END VIEW
L
SEATING
PLANE
L1
TOP VIEW
DIM
MIN
INCHES
NOM
A
A1
A2
b
c
D
E
E1
e
L
L1
-0
0.0295
0.0059
0.0031
----0.0157
--
-----0.1181 BSC
0.1929 BSC
0.1181 BSC
0.0197 BSC
0.0236
0.0374 REF
MAX
0.0433
0.0059
0.0374
0.0118
0.0091
----0.0315
--
MIN
MILLIMETERS
NOM
NOTE
MAX
-0
0.75
0.15
0.08
----0.40
--
-----3.00 BSC
4.90 BSC
3.00 BSC
0.50 BSC
0.60
0.95 REF
1.10
0.15
0.95
0.30
0.23
----0.80
--
4, 5
2
3
Notes: 1. Reference document: JEDEC MO-187
2. D does not include mold flash or protrusions which is 0.15 mm max. per side.
3. E1 does not include inter-lead flash or protrusions which is 0.15 mm max per side.
4. Dimension b does not include a total allowable dambar protrusion of 0.08 mm max.
5. Exceptions to JEDEC dimension.
THERMAL CHARACTERISTICS
Parameter
Junction to Ambient Thermal Impedance
24
JEDEC 2-Layer
JEDEC 4-Layer
Symbol
Min
Typ
Max
Units
θJA
θJA
-
170
100
-
°C/W
°C/W
DS844F1
CS2300-OTP
10.ORDERING INFORMATION
The CS2300-OTP is ordered as an un-programmed device. The CS2300-OTP can also be factory programmed for
large quantity orders. Please see “Programming Information” on page 23 for more details.
Product
Description
Package
Pb-Free
CS2300-OTP
Clocking Device
10L-MSOP
Yes
CS2300-OTP
Clocking Device
10L-MSOP
Yes
CDK2000
Evaluation Platform
-
Yes
DS844F1
Grade
Commercial
-
Temp Range Container
Order#
-10° to +70°C
Rail
CS2300P-CZZ
-10° to +70°C
Tape and
Reel
CS2300P-CZZR
-
-
CDK2000-LCO
25
CS2300-OTP
11.REVISION HISTORY
Release
F1
Changes
Updated Period Jitter specification in “AC Electrical Characteristics” on page 7.
Added “PLL Performance Plots” section on page 8.
Removed CLK_IN Skipping Mode.
Removed Auto R-Mod.
Added Mode pin toggle requirement to startup for CDK programmed devices to “Required Power Up
Sequencing for Programmed Devices” on page 18.
Contacting Cirrus Logic Support
For all product questions and inquiries, contact a Cirrus Logic Sales Representative.
To find one nearest you, go to www.cirrus.com.
IMPORTANT NOTICE
Cirrus Logic, Inc. and its subsidiaries (“Cirrus”) believe that the information contained in this document is accurate and reliable. However, the information is subject
to change without notice and is provided “AS IS” without warranty of any kind (express or implied). Customers are advised to obtain the latest version of relevant
information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale
supplied at the time of order acknowledgment, including those pertaining to warranty, indemnification, and limitation of liability. No responsibility is assumed by Cirrus
for the use of this information, including use of this information as the basis for manufacture or sale of any items, or for infringement of patents or other rights of third
parties. This document is the property of Cirrus and by furnishing this information, Cirrus grants no license, express or implied under any patents, mask work rights,
copyrights, trademarks, trade secrets or other intellectual property rights. Cirrus owns the copyrights associated with the information contained herein and gives consent for copies to be made of the information only for use within your organization with respect to Cirrus integrated circuits or other products of Cirrus. This consent
does not extend to other copying such as copying for general distribution, advertising or promotional purposes, or for creating any work for resale.
CERTAIN APPLICATIONS USING SEMICONDUCTOR PRODUCTS MAY INVOLVE POTENTIAL RISKS OF DEATH, PERSONAL INJURY, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE (“CRITICAL APPLICATIONS”). CIRRUS PRODUCTS ARE NOT DESIGNED, AUTHORIZED OR WARRANTED FOR USE
IN PRODUCTS SURGICALLY IMPLANTED INTO THE BODY, AUTOMOTIVE SAFETY OR SECURITY DEVICES, LIFE SUPPORT PRODUCTS OR OTHER CRITICAL APPLICATIONS. INCLUSION OF CIRRUS PRODUCTS IN SUCH APPLICATIONS IS UNDERSTOOD TO BE FULLY AT THE CUSTOMER’S RISK AND CIRRUS DISCLAIMS AND MAKES NO WARRANTY, EXPRESS, STATUTORY OR IMPLIED, INCLUDING THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
FITNESS FOR PARTICULAR PURPOSE, WITH REGARD TO ANY CIRRUS PRODUCT THAT IS USED IN SUCH A MANNER. IF THE CUSTOMER OR CUSTOMER’S CUSTOMER USES OR PERMITS THE USE OF CIRRUS PRODUCTS IN CRITICAL APPLICATIONS, CUSTOMER AGREES, BY SUCH USE, TO FULLY
INDEMNIFY CIRRUS, ITS OFFICERS, DIRECTORS, EMPLOYEES, DISTRIBUTORS AND OTHER AGENTS FROM ANY AND ALL LIABILITY, INCLUDING ATTORNEYS’ FEES AND COSTS, THAT MAY RESULT FROM OR ARISE IN CONNECTION WITH THESE USES.
Cirrus Logic, Cirrus, and the Cirrus Logic logo designs are trademarks of Cirrus Logic, Inc. All other brand and product names in this document may be trademarks
or service marks of their respective owners.
26
DS844F1