IDT ICS849N202I

FemtoClock® NG Universal Frequency
Translator
ICS849N202I
DATA SHEET
General Description
Features
The ICS849N202I is a highly flexible FemtoClock® NG general
purpose, low phase noise Universal Frequency Translator /
Synthesizer with alarm and monitoring functions suitable for
networking and communications applications. It is able to generate
any output frequency in the 0.98MHz - 312.5MHz range and most
output frequencies in the 312.5MHz - 1,300MHz range (see Table 3
for details). A wide range of input reference clocks and a range of
low-cost fundamental mode crystal frequencies may be used as the
source for the output frequency.
•
•
•
•
•
Zero ppm frequency translation
The ICS849N202I has three operating modes to support a very
broad spectrum of applications:
•
•
•
Input frequency range: 8kHz - 710MHz
Synthesizes output frequencies from a 16MHz - 40MHz
fundamental mode crystal.
•
Fractional feedback division is used, so there are no
requirements for any specific crystal frequency to produce the
desired output frequency with a high degree of accuracy.
Universal Frequency Translator (UFT) / Frequency Synthesizer
Two outputs, individually programmable as LVPECL or LVDS
•
•
1) Frequency Synthesizer
•
4TH generation FemtoClock® NG technology
Programmable output frequency: 0.98MHz up to 1,300MHz
Two differential inputs support the following input types:
LVPECL, LVDS, LVHSTL, HCSL
Crystal input frequency range: 16MHz - 40MHz
Two factory-set register configurations for power-up default state
•
•
•
•
2) High-Bandwidth Frequency Translator
Both outputs may be set to use 2.5V or 3.3V output levels
Power-up default configuration pin or register selectable
Configurations customized via One-Time Programmable ROM
Settings may be overwritten after power-up via I2C
I2C Serial interface for register programming
•
RMS phase jitter at 125MHz, using a 40MHz crystal
(12kHz - 20MHz): 510fs (typical), Low Bandwidth Mode (FracN)
Translates any input clock in the 16MHz - 710MHz frequency
range into any supported output frequency.
•
RMS phase jitter at 400MHz, using a 40MHz crystal
(12kHz - 40MHz): 321fs (typical), Synthesizer Mode (Integer FB)
This mode has a high PLL loop bandwidth in order to track input
reference changes, such as Spread-Spectrum Clock
modulation, so it will not attenuate much jitter on the input
reference.
•
Output supply voltage modes:
VCC/VCCA/VCCO
3.3V/3.3V/3.3V
3.3V/3.3V/2.5V (LVPECL only)
2.5V/2.5V/2.5V
•
•
-40°C to 85°C ambient operating temperature
One usage example might be to install the device on a line card with
two optional daughter cards: an OC-12 option requiring a 622.08MHz
LVDS clock translated from a 19.44MHz input and a Gigabit Ethernet
option requiring a 125MHz LVPECL clock translated from the same
19.44MHz input reference.
CLK_ACTIVE
nc
1
40 39 38 37 36 35 34 33 32 31
30
XTAL_OUT
2
29
VCC
VCC
3
ICS849N202I
28
OE0
CLK_SEL
4
Q0
5
26
nQ0
nCLK0
6
25
VCCO
VCC
7
24
Q1
VEE
8
40 Lead VFQFN
6mm x 6mm x 0.925mm
K Package
Top View
27
CLK0
nQ1
CLK1
9
23
22
10
21
VEE
LOCK_IND
OE1
nc
nc
S_A0
S_A1
nc
1
CONFIG
11 12 13 14 15 16 17 18 19 20
To implement other configurations, these power-up default settings
can be overwritten after power-up using the I2C interface and the
device can be completely reconfigured. However, these settings
would have to be re-written next time the device powers-up.
SEPTEMBER 26, 2011
LF0
XTAL_IN
nCLK1
ICS849N202CKI REVISION A
LF1
This device provides two factory-programmed default power-up
configurations burned into One-Time Programmable (OTP) memory.
The configuration to be used is selected by the CONFIG pin. The two
configurations are specified by the customer and are programmed by
IDT during the final test phase from an on-hand stock of blank
devices. The two configurations may be completely independent of
one another.
VEE
XTALBAD
Pin Assignment
HOLDOVER
This mode supports PLL loop bandwidths in the 10Hz - 580Hz
range and makes use of an external crystal to provide
significant jitter attenuation.
Available in lead-free (RoHS 6) package
SCLK
•
Translates any input clock in the 8kHz -710MHz frequency
range into any supported output frequency.
CLK0BAD
Applications: Networking & Communications.
SDATA
•
•
VCCA
3) Low-Bandwidth Frequency Translator
CLK1BAD
•
VCC
Applications: PCI Express, Computing, General Purpose
PLL_BYPASS
•
•
©2011 Integrated Device Technology, Inc.
ICS849N202I Data Sheet
FemtoClock® NG Universal Frequency Translator
Complete Block Diagram
PLL_BYPASS
XTAL
XTAL_IN
XTA L_OUT
1
OSC
PD/LF
Output Divider
Q0
÷N[10:0]
FemtoClock® NG
VCO
1995 - 2600 MHz
nQ0
0
OE0
Feedback Divider
÷M_INT
[7:0]
Q1
÷M_FRAC
[17:0]
nQ1
OE1
ADC
LF1
CLK_SEL
÷4
CLK0
nCLK0
CLK1
nCLK1
0
R3
÷M1[16:0]
÷P[16:0]
PD/CP
1
RS
CP
POR
OTP
Register Set 0
0
Register Set 1
1
SCLK, S_A0, S_A1
SDATA
SEPTEMBER 26, 2011
CS
Status Indicators
Control Logic
CLK_ACTIVE
LOCK_IND
XTALBAD
CLK0BAD
CLK1BAD
HOLDOVER
Global Registers
ICS849N202CKI REVISION A
LF0
C3
CONFIG
2
©2011 Integrated Device Technology, Inc.
ICS849N202I Data Sheet
FemtoClock® NG Universal Frequency Translator
Table 1. Pin Descriptions
Number
Name
Type
Description
1
2
XTAL_IN
XTAL_OUT
Input
Crystal Oscillator interface designed for 12pF parallel resonant crystals.
XTAL_IN (pin 1) is the input and XTAL_OUT (pin 2) is the output.
3, 7, 13, 29
VCC
Power
Core supply pins. All must be either 3.3V or 2.5V.
Input clock select. Selects the active differential clock input. LVCMOS/LVTTL
interface levels.
0 = CLK0, nCLK0 (default)
1 = CLK1, nCLK1
4
CLK_SEL
Input
Pulldown
5
CLK0
Input
Pulldown
Non-inverting differential clock input.
Pullup/
Pulldown
Inverting differential clock input. VCC/2 default when left floating (set by the
internal pullup and pulldown resistors).
6
nCLK0
Input
8, 21, 35
VEE
Power
9
CLK1
Input
Pulldown
Non-inverting differential clock input.
Pullup/
Pulldown
Inverting differential clock input. VCC/2 default when left floating (set by the
internal pullup and pulldown resistors).
10
nCLK1
Input
11, 19,
20, 32
nc
Unused
Negative supply pins.
No connect. These pins are to be left unconnected.
Bypasses the VCXO PLL. In bypass mode, outputs are clocked off the falling
edge of the input reference. LVCMOS/LVTTL interface levels.
0 = PLL Mode (default)
1 = PLL Bypassed
12
PLL_BYPASS
Input
Pulldown
14
SDATA
I/O
Pullup
I2C Data Input/Output. Open drain.
15
SCLK
Input
Pullup
I2C Clock Input. LVCMOS/LVTTL interface levels.
16
CONFIG
Input
Pulldown
Configuration Pin. Selects between one of two factory programmable pre-set
power-up default configurations. The two configurations can have different
output/input frequency translation ratios, different PLL loop bandwidths, etc.
These default configurations can be overwritten after power-up via I2C if the
user so desires. LVCMOS/LVTTL interface levels.
0 = Configuration 0 (default)
1 = Configuration 1
17
S_A1
Input
Pulldown
I2C Address Bit 1. LVCMOS/LVTTL interface levels.
18
S_A0
Input
Pulldown
I2C Address Bit 0. LVCMOS/LVTTL interface levels.
22
OE1
Input
Pullup
23, 24
nQ1, Q1
Output
Differential output. Output type is programmable to LVDS or LVPECL interface
levels.
25
VCCO
Power
Output supply pins for Q1, nQ1 and Q0, nQ0 outputs. Either 2.5V or 3.3V.
26, 27
nQ0, Q0
Output
Differential output. Output type is programmable to LVDS or LVPECL interface
levels.
28
OE0
Input
30
LOCK_IND
Output
Lock Indicator - indicates that the PLL is in a locked condition. LVCMOS/LVTTL
interface levels.
Output
Indicates which of the two differential clock inputs is currently selected.
LVCMOS/LVTTL interface levels.
0 = CLK0, nCLK0 differential input pair
1 = CLK1, nCLK1 differential input pair
31
CLK_ACTIVE
ICS849N202CKI REVISION A
SEPTEMBER 26, 2011
Pullup
Active High Output Enable for Q1, nQ1. LVCMOS/LVTTL interface levels.
0 = Output pins high-impedance
1 = Output switching (default)
Active High Output Enable for Q0, nQ0. LVCMOS/LVTTL interface levels.
0 = Output pins high-impedance
1 = Output switching (default)
3
©2011 Integrated Device Technology, Inc.
ICS849N202I Data Sheet
FemtoClock® NG Universal Frequency Translator
Number
Name
33, 34
LF0, LF1
Input
Type
Description
Connection for external loop filter components.
36
VCCA
Power
Analog supply voltage. See Applications section for details on how to connect
this pin.
37
HOLDOVER
Output
Alarm output reflecting if the device is in a holdover state. LVCMOS/LVTTL
interface levels.
0 = Device is locked to a valid input reference
1 = Device is not locked to a valid input reference
38
CLK0BAD
Output
Alarm output reflecting the state of CLK0. LVCMOS/LVTTL interface levels.
0 = Input Clock 0 is switching within specifications
1 = Input Clock 0 is out of specification
39
CLK1BAD
Output
Alarm output reflecting the state of CLK1. LVCMOS/LVTTL interface levels.
0 = Input Clock 1 is switching within specifications
1 = Input Clock 1 is out of specification
40
XTALBAD
Output
Alarm output reflecting the state of XTAL. LVCMOS/LVTTL interface levels.
0 = crystal is switching within specifications
1 = crystal is out of specification
NOTE: Pullup and Pulldown refer to internal input resistors. See Table 2, Pin Characteristics, for typical values.
Table 2. Pin Characteristics
Symbol
Parameter
CIN
Input Capacitance
3.5
pF
RPULLUP
Input Pullup Resistor
51
kΩ
RPULLDOWN
Input Pulldown Resistor
51
kΩ
ICS849N202CKI REVISION A
Test Conditions
SEPTEMBER 26, 2011
4
Minimum
Typical
Maximum
Units
©2011 Integrated Device Technology, Inc.
ICS849N202I Data Sheet
FemtoClock® NG Universal Frequency Translator
Functional Description
The ICS849N202I is designed to provide two copies of almost any
desired output frequency within its operating range (0.98 - 1300MHz)
from any input source in the operating range (8kHz - 710MHz). It is
capable of synthesizing frequencies from a crystal or crystal
oscillator source. The output frequency is generated regardless of
the relationship to the input frequency. The output frequency will be
exactly the required frequency in most cases. In most others, it will
only differ from the desired frequency by a few ppb. IDT configuration
software will indicate the frequency error, if any. The ICS849N202I
can translate the desired output frequency from one of two input
clocks. Again, no relationship is required between the input and
output frequencies in order to translate to the output clock rate. In this
frequency translation mode, a low-bandwidth, jitter attenuation option
is available that makes use of an external fixed-frequency crystal or
crystal oscillator to translate from a noisy input source. If the input
clock is known to be fairly clean or if some modulation on the input
needs to be tracked, then the high-bandwidth frequency translation
mode can be used, without the need for the external crystal.
ratios within the ICS849N202I for the two different card
configurations. Access via I2C would not be necessary for operation
using either of the internal configurations.
Operating Modes
The ICS849N202I has three operating modes which are set by the
MODE_SEL[1:0] bits. There are two frequency translator modes low bandwidth and high bandwidth and a frequency synthesizer
mode. The device will operate in the same mode regardless of which
configuration is active.
Please make use of IDT-provided configuration applications to
determine the best operating settings for the desired configurations
of the device.
Output Dividers & Supported Output Frequencies
In all 3 operating modes, the output stage behaves the same way, but
different operating frequencies can be specified in the two
configurations.
The input clock references and crystal input are monitored
continuously and appropriate alarm outputs are raised both as
register bits and hard-wired pins in the event of any
out-of-specification conditions arising. Clock switching is supported
in manual, revertive & non-revertive modes.
The internal VCO is capable of operating in a range anywhere from
1.995GHz - 2.6GHz. It is necessary to choose an integer multiplier of
the desired output frequency that results in a VCO operating
frequency within that range. The output divider stage N[10:0] is
limited to selection of integers from 2 to 2046. Please refer to Table 3
for the values of N applicable to the desired output frequency.
The ICS849N202I has two factory-programmed configurations that
may be chosen from as the default operating state after reset. This is
intended to allow the same device to be used in two different
applications without any need for access to the I2C registers. These
defaults may be over-written by I2C register access at any time, but
those over-written settings will be lost on power-down. Please
contact IDT if a specific set of power-up default settings is desired.
Table 3. Output Divider Settings & Frequency Ranges
Register
Setting
Frequency
Divider
Minimum
fOUT
Maximum
fOUT
Nn[10:0]
N
(MHz)
(MHz)
Configuration Selection
0000000000x
2
997.5
1300
The ICS849N202I comes with two factory-programmed default
configurations. When the device comes out of power-up reset the
selected configuration is loaded into operating registers. The
ICS849N202I uses the state of the CONFIG pin or CONFIG register
bit (controlled by the CFG_PIN_REG bit) to determine which
configuration is active. When the output frequency is changed either
via the CONFIG pin or via internal registers, the output behavior may
not be predictable during the register writing and output settling
periods. Devices sensitive to glitches or runt pulses may have to be
reset once reconfiguration is complete.
00000000010
2
997.5
1300
00000000011
3
665
866.7
00000000100
4
498.75
650
00000000101
5
399
520
0000000011x
6
332.5
433.3
0000000100x
8
249.4
325
0000000101x
10
199.5
260
0000000110x
12
166.3
216.7
0000000111x
14
142.5
185.7
0000001000x
16
124.7
162.5
Once the device is out of reset, the contents of the operating registers
can be modified by write access from the I2C serial port. Users that
have a custom configuration programmed may not require I2C
access.
It is expected that the ICS849N202I will be used almost exclusively
in a mode where the selected configuration will be used from device
power-up without any changes during operation. For example, the
device may be designed into a communications line card that
supports different I/O modules such as a standard OC-12 module
running at 622.08MHz or a (255/237) FEC rate OC-12 module
running at 669.32MHz. The different I/O modules would result in a
different level on the CONFIG pin which would select different divider
ICS849N202CKI REVISION A
SEPTEMBER 26, 2011
5
0000001001x
18
110.8
144.4
...
Even N
1995 / N
2600 / N
1111111111x
2046
0.98
1.27
©2011 Integrated Device Technology, Inc.
ICS849N202I Data Sheet
FemtoClock® NG Universal Frequency Translator
Frequency Synthesizer Mode
The input reference frequency range is now extended up to 710MHz.
A pre-divider stage P is needed to keep the operating frequencies at
the phase detector within limits.
This mode of operation allows an arbitrary output frequency to be
generated from a fundamental mode crystal input. As can be seen
from the block diagram in Figure 1, only the upper feedback loop is
used in this mode of operation. It is recommended that CLK0 and
CLK1 be left unused in this mode of operation.
Low-Bandwidth Frequency Translator Mode
As can be seen from the block diagram in Figure 3, this mode
involves two PLL loops. The lower loop with the large integer dividers
is the low bandwidth loop and it sets the output-to-input frequency
translation ratio.This loop drives the upper DCXO loop (digitally
controlled crystal oscillator) via an analog-digital converter.
The upper feedback loop supports a delta-sigma fractional feedback
divider. This allows the VCO operating frequency to be a non-integer
multiple of the crystal frequency. By using an integer multiple only,
lower phase noise jitter on the output can be achieved, however the
use of the delta-sigma divider logic will provide excellent
performance on the output if a fractional divisor is used.
PLL_BYPASS
XTAL
XTAL_IN
XTAL_OUT
1
OSC
PLL_BYPASS
XTAL
1
XTAL_IN
OSC
XTAL_OUT
÷M_INT
[7:0]
Q0
nQ0
0
OE0
OE1
LF1
CLK_SEL
nQ1
CLK0
nCLK0
CLK1
nCLK1
÷4
0
R3
÷M1[16:0]
÷P[16:0]
PD/CP
1
OTP
OTP
Register Set 1
1
SDATA
0
Register Set 1
1
SCLK, S_A0, S_A1
0
SCLK, S_A0, S_A1
Register Set 0
LOCK_IND
XTALBAD
SDATA
CS
CLK_ACTIVE
LOCK_IND
XTALBAD
CLK0BAD
CLK1BAD
HOLDOVER
Status Indicators
Register Set 0
C3
RS
Status Indicators
Control Logic
Global Registers
Global Registers
LF0
CP
POR
Control Logic
nQ1
ADC
OE1
POR
Q1
÷M_FRAC
[17:0]
Q1
÷M_FRAC
[17:0]
nQ0
OE0
Feedback Divider
÷M_INT
[7:0]
Q0
0
Feedback Divider
Output Divider
÷N[10:0]
FemtoClock® NG
VCO
1995 - 2600 MHz
PD/LF
Output Divider
÷N[10:0]
FemtoClock® NG
VCO
1995 - 2600 MHz
PD/LF
CONFIG
Figure 3. Low Bandwidth Frequency Translator Mode
Block Diagram
CONFIG
The phase detector of the lower loop is designed to work with
frequencies in the 8kHz - 16kHz range. The pre-divider stage is used
to scale down the input frequency by an integer value to achieve a
frequency in this range. By dividing down the fed-back VCO
operating frequency by the integer divider M1[16:0] to as close as
possible to the same frequency, exact output frequency translations
can be achieved.
Figure 1. Frequency Synthesizer Mode Block Diagram
High-Bandwidth Frequency Translator Mode
This mode of operation is used to translate one of two input clocks of
the same nominal frequency into an output frequency with little jitter
attenuation. As can be seen from the block diagram in Figure 2,
similarly to the Frequency Synthesizer mode, only the upper
feedback loop is used.
Alarm Conditions & Status Bits
PLL_BYPASS
1
÷N[10:0]
FemtoClock® NG
VCO
1995 - 2600 MHz
PD/LF
The ICS849N202I monitors a number of conditions and reports their
status via both output pins and register bits. All alarms will behave as
indicated below in all modes of operation, but some of the conditions
monitored have no valid meaning in some operating modes. For
example, the status of CLK0BAD, CLK1BAD and CLK_ACTIVE are
not relevant in Frequency Synthesizer mode. The outputs will still be
active and it is left to the user to determine which to monitor and how
to respond to them based on the known operating mode.
Output Divider
0
Q0
nQ0
OE0
Feedback Divider
÷M_INT
[7:0]
÷M_FRAC
[17:0]
Q1
nQ1
OE1
CLK_SEL
CLK0
nCLK0
CLK1
nCLK1
CLK_ACTIVE - indicates which input clock reference is being used to
derive the output frequency.
0
÷P[16:0]
1
POR
Status Indicators
Control Logic
OTP
Register Set 0
0
Register Set 1
1
SCLK, S_A0, S_A1
SDATA
LOCK_IND - This status is asserted on the pin & register bit when the
PLL is locked to the appropriate input reference for the chosen mode
of operation. The status bit will not assert until frequency lock has
been achieved, but will de-assert once lock is lost.
CLK_ACTIVE
LOCK_IND
Global Registers
CLK0BAD
CLK1BAD
HOLDOVER
CONFIG
Figure 2. High Bandwidth Frequency Translator Mode
Block Diagram
ICS849N202CKI REVISION A
SEPTEMBER 26, 2011
6
©2011 Integrated Device Technology, Inc.
ICS849N202I Data Sheet
FemtoClock® NG Universal Frequency Translator
XTALBAD - indicates if valid edges are being received on the crystal
input. Detection is performed by comparing the input to the feedback
signal at the upper loop’s Phase / Frequency Detector (PFD). If three
edges are received on the feedback without an edge on the crystal
input, the XTALBAD alarm is asserted on the pin & register bit. Once
an edge is detected on the crystal input, the alarm is immediately
deasserted.
This will occur even if there is a valid clock on the non-selected
reference input. The device will recover from holdover / free-run state
once a valid clock is re-established on the selected reference input.
CLK0BAD - indicates if valid edges are being received on the CLK0
reference input. Detection is performed by comparing the input to the
feedback signal at the appropriate Phase / Frequency Detector
(PFD). When operating in high-bandwidth mode, the feedback at the
upper PFD is used. In low-bandwidth mode, the feedback at the lower
PFD is used. If three edges are received on the feedback without an
edge on the divided down (÷P) CLK0 reference input, the CLK0BAD
alarm is asserted on the pin & register bit. Once an edge is detected
on the CLK0 reference input, the alarm is deasserted.
Automatic Switching Mode
The ICS849N202I will only switch input references on command from
the user. The user must either change the CLK_SEL register bit (if in
Manual via Register) or CLK_SEL input pin (if in Manual via Pin).
When the AUTO_MAN[1:0] field is set to either of the automatic
selection modes (Revertive or Non-Revertive), the ICS849N202I
determines which input reference it prefers / starts from by the state
of the CLK_SEL register bit only. The CLK_SEL input pin is not used
in either Automatic switching mode.
When starting from an unlocked condition, the device will lock to the
input reference indicated by the CLK_SEL register bit. It will not pay
attention to the non-selected input reference until a locked state has
been achieved. This is necessary to prevent ‘hunting’ behavior during
the locking phase.
CLK1BAD - indicates if valid edges are being received on the CLK1
reference input. Behavior is as indicated for the CLK0BAD alarm, but
with the CLK1 input being monitored and the CLK1BAD output pin &
register bits being affected.
Once the ICS849N202I has achieved a stable lock, it will remain
locked to the preferred input reference as long as there is a valid clock
on it. If at some point, that clock fails, then the device will
automatically switch to the other input reference as long as there is a
valid clock there. If there is not a valid clock on either input reference,
the ICS849N202I will go into holdover (Low Bandwidth Frequency
Translator mode) or free-run (High Bandwidth Frequency Translator
mode) state. In either case, the HOLDOVER alarm will be raised.
HOLDOVER - indicates that the device is not locked to a valid input
reference clock. This can occur in Manual switchover mode if the
selected reference input has gone bad, even if the other reference
input is still good. In automatic mode, this will only assert if both input
references are bad.
Input Reference Selection and Switching
The device will recover from holdover / free-run state once a valid
clock is re-established on either reference input. If clocks are valid on
both input references, the device will choose the reference indicated
by the CLK_SEL register bit.
When operating in Frequency Synthesizer mode, the CLK0 and
CLK1 inputs are not used and the contents of this section do not
apply. Except as noted below, when operating in either High or Low
Bandwidth Frequency Translator mode, the contents of this section
apply equally when in either of those modes.
If running from the non-preferred input reference and a valid clock
returns, there is a difference in behavior between Revertive and
Non-revertive modes. In Revertive mode, the device will switch back
to the reference indicated by the CLK_SEL register bit even if there
is still a valid clock on the non-preferred reference input. In
Non-revertive mode, the ICS849N202I will not switch back as long as
the non-preferred input reference still has a valid clock on it.
Both input references CLK0 and CLK1 must be the same nominal
frequency. These may be driven by any type of clock source,
including crystal oscillator modules. A difference in frequency may
cause the PLL to lose lock when switching between input references.
Please contact IDT for the exact limits for your situation.
The global control bits AUTO_MAN[1:0] dictate the order of priority
and switching mode to be used between the CLK0 and CLK1 inputs.
Switchover Behavior of the PLL
Even though the two input references have the same nominal
frequency, there may be minor differences in frequency and
potentially large differences in phase between them. The
ICS849N202I will adjust its output to the new input reference. It will
use Phase Slope Limiting to adjust the output phase at a fixed
maximum rate until the output phase and frequency are now aligned
to the new input reference. Phase will always be adjusted by
extending the clock period of the output so that no unacceptably short
clock periods are generated on the output ICS849N202I.
Manual Switching Mode
When the AUTO_MAN[1:0] field is set to Manual via Pin, then the
ICS849N202I will use the CLK_SEL input pin to determine which
input to use as a reference. Similarly, if set to Manual via Register,
then the device will use the CLK_SEL register bit to determine the
input reference. In either case, the PLL will lock to the selected
reference if there is a valid clock present on that input.
If there is not a valid clock present on the selected input, the
ICS849N202I will go into holdover (Low Bandwidth Frequency
Translator mode) or free-run (High Bandwidth Frequency Translator
mode) state. In either case, the HOLDOVER alarm will be raised.
ICS849N202CKI REVISION A
SEPTEMBER 26, 2011
7
©2011 Integrated Device Technology, Inc.
ICS849N202I Data Sheet
FemtoClock® NG Universal Frequency Translator
Holdover / Free-run Behavior
The two outputs are individually selectable as LVDS or LVPECL
output types via the Q0_TYPE and Q1_TYPE register bits. These
two selection bits are provided in each configuration to allow different
output type settings under each configuration.
When both input references have failed (Automatic mode) or the
selected input has failed (Manual mode), the ICS849N202I will enter
holdover (Low Bandwidth Frequency Translator mode) or free-run
(High Bandwidth Frequency Translator mode) state . In both cases,
once the input reference is lost, the PLL will stop making adjustments
to the output phase.
The two outputs can be enabled individually also via both register
control bits and input pins. When both the OEn register bit and OEn
pin are enabled, then the appropriate output is enabled. The OEn
register bits default to enabled so that by default the outputs can be
directly controlled by the input pins. Similarly, the input pins are
provisioned with weak pull-ups so that if they are left unconnected,
the output state can be directly controlled by the register bits. When
the differential output is in the disabled state, it will show a high
impedance condition.
If operating in Low Bandwidth Frequency Translation mode, the PLL
will continue to reference itself to the local oscillator and will hold its
output phase and frequency in relation to that source. Output stability
is determined by the stability of the local oscillator in this case.
However, if operating in High Bandwidth Frequency Translation
mode, the PLL no longer has any frequency reference to use and
output stability is now determined by the stability of the internal VCO.
Serial Interface Configuration Description
If the device is programmed to perform Manual switching, once the
selected input reference recovers, the ICS849N202I will switch back
to that input reference. If programmed for either Automatic mode, the
device will switch back to whichever input reference has a valid clock
first.
The ICS849N202I has an I2C-compatible configuration interface to
access any of the internal registers (Table 4D) for frequency and PLL
parameter programming. The ICS849N202I acts as a slave device on
the I2C bus and has the address 0b11011xx, where xx is set by the
values on the S_A0 & S_A1 pins (see Table 4A for details). The
interface accepts byte-oriented block write and block read
operations. An address byte (P) specifies the register address (Table
4D) as the byte position of the first register to write or read. Data
bytes (registers) are accessed in sequential order from the lowest to
the highest byte (most significant bit first, see table 4B, 4C). Read
and write block transfers can be stopped after any complete byte
transfer. It is recommended to terminate I2C the read or write transfer
after accessing byte #23.
The switchover that results from returning from holdover or free-run
is handled in the same way as a switch between two valid input
references as described in the previous section.
Output Configuration
The two outputs of the ICS849N202I both provide the same clock
frequency. Both must operate from the same output voltage level of
3.3V or 2.5V, although this output voltage may be less than or equal
to the core voltage (3.3V or 2.5V) the rest of the device is operating
from. The output voltage level used on the two outputs is supplied on
the VCCO pin.
For full electrical I2C compliance, it is recommended to use external
pull-up resistors for SDATA and SCLK. The internal pull-up resistors
have a size of 50kΩ typical.
Note: if a different device slave address is desired, please contact
IDT.
Table 4A. I2C Device Slave Address
1
1
0
1
1
S_A1
S_A0
R/W
Table 4B. Block Write Operation
Bit
Description
1
2:8
9
10
11:18
19
20:27
28
29-36
37
...
...
...
START
Slave
Address
W (0)
ACK
Address
Byte (P)
ACK
Data Byte
(P)
ACK
Data Byte
(P+1)
ACK
Data Byte
...
ACK
STOP
1
7
1
1
8
1
8
1
8
1
8
1
1
9
10
11:18
19
Address
Byte (P)
A
C
K
Repeate
d START
8
1
1
Length (bits)
Table 4C. Block Read Operation
Bit
1
START
Slave
Address
W
(0)
A
C
K
1
7
1
1
Description
Length (bits)
2:8
ICS849N202CKI REVISION A
SEPTEMBER 26, 2011
20
21:27
28
29
30:37
38
39-46
47
...
...
...
Slave
Address
R
(1)
A
C
K
Data
Byte (P)
A
C
K
Data Byte
(P+1)
A
C
K
Data Byte
...
A
C
K
STOP
7
1
1
8
1
8
1
8
1
1
8
©2011 Integrated Device Technology, Inc.
ICS849N202I Data Sheet
FemtoClock® NG Universal Frequency Translator
Register Descriptions
Please consult IDT for configuration software and/or programming guides to assist in selection of optimal register settings for the desired
configurations.
Table 4D. I C Register Map
2
Reg
Binary
Register
Address
Register Bit
D7
D6
D5
D4
D3
D2
D1
D0
0
00000
MFRAC0[17]
MFRAC0[16]
MFRAC0[15]
MFRAC0[14]
MFRAC0[13]
MFRAC0[12]
MFRAC0[11]
MFRAC0[10]
1
00001
MFRAC1[17]
MFRAC1[16]
MFRAC1[15]
MFRAC1[14]
MFRAC1[13]
MFRAC1[12]
MFRAC1[11]
MFRAC1[10]
2
00010
MFRAC0[9]
MFRAC0[8]
MFRAC0[7]
MFRAC0[6]
MFRAC0[5]
MFRAC0[4]
MFRAC0[3]
MFRAC0[2]
3
00011
MFRAC1[9]
MFRAC1[8]
MFRAC1[7]
MFRAC1[6]
MFRAC1[5]
MFRAC1[4]
MFRAC1[3]
MFRAC1[2]
4
00100
MFRAC0[1]
MFRAC0[0]
MINT0[7]
MINT0[6]
MINT0[5]
MINT0[4]
MINT0[3]
MINT0[2]
5
00101
MFRAC1[1]
MFRAC1[0]
MINT1[7]
MINT1[6]
MINT1[5]
MINT1[4]
MINT1[3]
MINT1[2]
6
00110
MINT0[1]
MINT0[0]
P0[16]
P0[15]
P0[14]
P0[13]
P0[12]
P0[11]
7
00111
MINT1[1]
MINT1[0]
P1[16]
P1[15]
P1[14]
P1[13]
P1[12]
P1[11]
8
01000
P0[10]
P0[9]
P0[8]
P0[7]
P0[6]
P0[5]
P0[4]
P0[3]
9
01001
P1[10]
P1[9]
P1[8]
P1[7]
P1[6]
P1[5]
P1[4]
P1[3]
10
01010
P0[2]
P0[1]
P0[0]
M1_0[16]
M1_0[15]
M1_0[14]
M1_0[13]
M1_0[12]
11
01011
P1[2]
P1[1]
P1[0]
M1_1[16]
M1_1[15]
M1_1[14]
M1_1[13]
M1_1[12]
12
01100
M1_0[11]
M1_0[10]
M1_0[9]
M1_0[8]
M1_0[7]
M1_0[6]
M1_0[5]
M1_0[4]
13
01101
M1_1[11]
M1_1[10]
M1_1[9]
M1_1[8]
M1_1[7]
M1_1[6]
M1_1[5]
M1_1[4]
14
01110
M1_0[3]
M1_0[2]
M1_0[1]
M1_0[0]
N0[10]
N0[9]
N0[8]
N0[7]
15
01111
M1_1[3]
M1_1[2]
M1_1[1]
M1_1[0]
N1[10]
N1[9]
N1[8]
N1[7]
16
10000
N0[6]
N0[5]
N0[4]
N0[3]
N0[2]
N0[1]
N0[0]
BW0[6]
17
10001
N1[6]
N1[5]
N1[4]
N1[3]
N1[2]
N1[1]
N1[0]
BW1[6]
18
10010
BW0[5]
BW0[4]
BW0[3]
BW0[2]
BW0[1]
BW0[0]
Q1_TYPE0
Q0_TYPE0
19
10011
BW1[5]
BW1[4]
BW1[3]
BW1[2]
BW1[1]
BW1[0]
Q1_TYPE1
Q0_TYPE1
20
10100
MODE_SEL[1]
MODE_SEL[0]
CONFIG
CFG_PIN_REG
OE1
OE0
Rsvd
Rsvd
21
10101
CLK_SEL
AUTO_MAN[1]
AUTO_MAN[0]
0
ADC_RATE[1]
ADC_RATE[0]
LCK_WIN[1]
LCK_WIN[0]
22
10110
1
0
1
0
0
0
0
0
23
10111
CLK_ACTIVE
HOLDOVER
CLK1BAD
CLK0BAD
XTAL_BAD
LOCK_IND
Rsvd
Rsvd
Register Bit Color Key
Configuration 0 Specific Bits
Configuration 1 Specific Bits
Global Control & Status Bits
ICS849N202CKI REVISION A
SEPTEMBER 26, 2011
9
©2011 Integrated Device Technology, Inc.
ICS849N202I Data Sheet
FemtoClock® NG Universal Frequency Translator
The register bits described in Table 4E are duplicated, with one set
applying for Configuration 0 and the other for Configuration 1. The
functions of the bits are identical, but only apply when the
configuration they apply to is enabled. Replace the lowercase n in the
bit field description with 0 or 1 to find the field’s location in the bitmap
in Table 4D.
Table 4E. Configuration-Specific Control Bits
Register Bits
Function
Q0_TYPEn
Determines the output type for output pair Q0, nQ0 for Configuration n.
0 = LVPECL
1 = LVDS
Q1_TYPEn
Determines the output type for output pair Q1, nQ1 for Configuration n.
0 = LVPECL
1 = LVDS
Pn[16:0]
M1_n[16:0]
M_INTn[7:0]
M_FRACn[17:0]
Reference Pre-Divider for Configuration n.
Integer Feedback Divider in Lower Feedback Loop for Configuration n.
Feedback Divider, Integer Value in Upper Feedback Loop for Configuration n.
Feedback Divider, Fractional Value in Upper Feedback Loop for Configuration n.
Nn[10:0]
Output Divider for Configuration n.
BWn[6:0]
Internal Operation Settings for Configuration n.
Please use IDT ICS849N202I Configuration Software to determine the correct settings for these bits for the specific
configuration. Alternatively, please consult with IDT directly for further information on the functions of these bits.The
function of these bits are explained in Tables 4J and 4K.
Table 4F. Global Control Bits
Register Bits
Function
MODE_SEL[1:0]
PLL Mode Select
00 = Low Bandwidth Frequency Translator
01 = Frequency Synthesizer
10 = High Bandwidth Frequency Translator
11 = High Bandwidth Frequency Translator
CFG_PIN_REG
Configuration Control. Selects whether the configuration selection function is under pin or register control.
0 = Pin Control
1 = Register Control
CONFIG
Configuration Selection. Selects whether the device uses the register configuration set 0 or 1. This bit only has an
effect when the CONFIG_PIN_REG bit is set to 1 to enable register control.
OE0
Output Enable Control for Output 0. Both this register bit and the corresponding Output Enable pin OE0 must be
asserted to enable the Q0, nQ0 output.
0 = Output Q0, nQ0 disabled
1 = Output Q0, nQ0 under control of the OE0 pin
OE1
Output Enable Control for Output 1. Both this register bit and the corresponding Output Enable pin OE1 must be
asserted to enable the Q1, nQ1 output.
0 = Output Q1, nQ1 disabled
1 = Output Q1, nQ1 under control of the OE1 pin
Rsvd
Reserved bits - user should write a ‘0’ to these bit positions if a write to these registers is needed
AUTO_MAN[1:0]
ICS849N202CKI REVISION A
Selects how input clock selection is performed.
00 = Manual Selection via pin only
01 = Automatic, non-revertive
10 = Automatic, revertive
11 = Manual Selection via register only
SEPTEMBER 26, 2011
10
©2011 Integrated Device Technology, Inc.
ICS849N202I Data Sheet
CLK_SEL
ADC_RATE[1:0]
LCK_WIN[1:0]
FemtoClock® NG Universal Frequency Translator
In manual clock selection via register mode, this bit will command which input clock is selected. In the automatic
modes, this indicates the primary clock input. In manual selection via pin mode, this bit has no effect.
0 = CLK0
1 = CLK1
Sets the ADC sampling rate in Low-Bandwidth Mode as a fraction of the crystal input frequency.
00 = Crystal Frequency / 16
01 = Crystal Frequency / 8
10 = Crystal Frequency / 4 (recommended)
11 = Crystal Frequency / 2
Sets the width of the window in which a new reference edge must fall relative to the feedback edge: 00 = 2usec
(recommended), 01 = 4usec, 10 = 8usec, 11 = 16usec
Table 4G. Global Status Bits
Register Bits
Function
CLK0BAD
Status Bit for input clock 0. This function is mirrored in the CLK0BAD pin.
0 = input CLK0 is good
1 = input CLK0 is bad. Self clears when input clock returns to good status
CLK1BAD
Status Bit for input clock 1. This function is mirrored in the CLK1BAD pin.
0 = input CLK1 is good
1 = input CLK1 is bad. Self clears when input clock returns to good status
XTALBAD
Status Bit. This function is mirrored on the XTALBAD pin.
0 = crystal input good
1 = crystal input bad. Self-clears when the XTAL clock returns to good status
LOCK_IND
Status bit. This function is mirrored on the LOCK_IND pin.
0 = PLL unlocked
1 = PLL locked
HOLDOVER
Status Bit. This function is mirrored on the HOLDOVER pin.
0 = Input to phase detector is within specifications and device is tracking to it
1 = Phase detector input is not within specifications and DCXO is frozen at last value
CLK_ACTIVE
Status Bit. Indicates which input clock is active. Automatically updates during fail-over switching. Status also
indicated on CLK_ACTIVE pin.
ICS849N202CKI REVISION A
SEPTEMBER 26, 2011
11
©2011 Integrated Device Technology, Inc.
ICS849N202I Data Sheet
FemtoClock® NG Universal Frequency Translator
Table 4J. BW[6:0] Bits
Mode
BW[6]
BW[5]
BW[4]
BW[3]
BW[2]
BW[1]
BW[0]
Synthesizer Mode
PLL2_LF[1]
PLL2_LF[0]
DSM_ORD
DSM_EN
PLL2_CP[1]
PLL2_CP[0]
PLL2_LOW_ICP
High-Bandwidth Mode
PLL2_LF[1]
PLL2_LF[0]
DSM_ORD
DSM_EN
PLL2_CP[1]
PLL2_CP[0]
PLL2_LOW_ICP
Low-Bandwidth Mode
ADC_GAIN[3]
ADC_GAIN[2]
ADC_GAIN[1]
ADC_GAIN[0]
PLL1_CP[1]
PLL1_CP[0]
PLL2_LOW_ICP
Table 4K. Functions of Fields in BW[6:0]
Register Bits
Function
PLL2_LF[1:0]
Sets loop filter values for upper loop PLL in Frequency Synthesizer & High-Bandwidth modes.
Defaults to setting of 00 when in Low Bandwidth Mode. See Table 4L for settings.
DSM_ORD
Sets Delta-Sigma Modulation to 2nd (0) or 3rd order (1) operation
Enables Delta-Sigma Modulator
0 = Disabled - feedback in integer mode only
1 = Enabled - feedback in fractional mode
DSM_EN
Upper loop PLL charge pump current settings:
00 = 173µA (defaults to this setting in Low Bandwidth Mode)
01 = 346µA
10 = 692µA
11 = reserved
PLL2_CP[1:0]
PLL2_LOW_ICP
Reduces Charge Pump current by 1/3 to reduce bandwidth variations resulting from higher feedback register
settings or high VCO operating frequency (>2.4GHz).
ADC_GAIN[3:0]
Gain setting for ADC in Low Bandwidth Mode.
Lower loop PLL charge pump current settings (lower loop is only used in Low Bandwidth Mode):
00 = 800µA
01 = 400µA
10 = 200µA
11 = 100µA
PLL1_CP[1:0]
Table 4L. High Bandwidth Frequency and Frequency Synthesizer Bandwidth Settings
Desired
Bandwidth
PLL2_CP
PLL2_LOW_ICP
PLL2_LF
Frequency Synthesizer Mode
200kHz
00
1
00
400kHz
01
1
01
800kHz
10
1
10
2MHz
10
1
11
High Bandwidth Frequency Translator Mode
200kHz
00
1
00
400kHz
01
1
01
800kHz
10
1
10
4MHz
10
0
11
NOTE: To achieve 4MHz bandwidth, reference to the phase detector should be 80MHz.
ICS849N202CKI REVISION A
SEPTEMBER 26, 2011
12
©2011 Integrated Device Technology, Inc.
ICS849N202I Data Sheet
FemtoClock® NG Universal Frequency Translator
Absolute Maximum Ratings
NOTE: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device.
These ratings are stress specifications only. Functional operation of product at these conditions or any conditions beyond
those listed in the DC Characteristics or AC Characteristics is not implied. Exposure to absolute maximum rating conditions for
extended periods may affect product reliability.
Item
Rating
Supply Voltage, VCC
3.63V
Inputs, VI
XTAL_IN
Other Inputs
0V to 2V
-0.5V to VCC + 0.5V
Outputs, VO (LVCMOS)
-0.5V to VCCO + 0.5V
Outputs, IO (LVPECL)
Continuous Current
Surge Current
50mA
100mA
Outputs, IO (LVDS)
Continuous Current
Surge Current
10mA
15mA
Package Thermal Impedance, θJA
32.4°C/W (0 mps)
Storage Temperature, TSTG
-65°C to 150°C
DC Electrical Characteristics
Table 5A. LVPECL Power Supply DC Characteristics, VCC = VCCO = 3.3V±5%, VEE = 0V, TA = -40°C to 85°C
Symbol
Parameter
Test Conditions
Minimum
Typical
Maximum
Units
VCC
Core Supply Voltage
3.135
3.3
3.465
V
VCCA
Analog Supply Voltage
VCC – 0.30
3.3
VCC
V
VCCO
Output Supply Voltage
3.135
3.3
3.465
V
IEE
Power Supply Current
320
mA
ICCA
Analog Supply Current
30
mA
Table 5B. LVPECL Power Supply DC Characteristics, VCC = 3.3V±5%, VCCO = 2.5V±5%, VEE = 0V, TA = -40°C to 85°C
Symbol
Parameter
Minimum
Typical
Maximum
Units
VCC
Core Supply Voltage
3.135
3.3
3.465
V
VCCA
Analog Supply Voltage
VCC – 0.30
3.3
VCC
V
VCCO
Output Supply Voltage
2.375
2.5
2.625
V
IEE
Power Supply Current
319
mA
ICCA
Analog Supply Current
30
mA
ICS849N202CKI REVISION A
Test Conditions
SEPTEMBER 26, 2011
13
©2011 Integrated Device Technology, Inc.
ICS849N202I Data Sheet
FemtoClock® NG Universal Frequency Translator
Table 5C. LVPECL Power Supply DC Characteristics, VCC = VCCO = 2.5V±5%, VEE = 0V, TA = -40°C to 85°C
Symbol
Parameter
Test Conditions
Minimum
Typical
Maximum
Units
VCC
Core Supply Voltage
2.375
2.5
2.625
V
VCCA
Analog Supply Voltage
VCC – 0.26
2.5
VCC
V
VCCO
Output Supply Voltage
2.375
2.5
2.625
V
IEE
Power Supply Current
304
mA
ICCA
Analog Supply Current
26
mA
Table 5D. LVDS Power Supply DC Characteristics, VCC = VCCO = 3.3V±5%, TA = -40°C to 85°C
Symbol
Parameter
Test Conditions
Minimum
Typical
Maximum
Units
VCC
Core Supply Voltage
3.135
3.3
3.465
V
VCCA
Analog Supply Voltage
VCC – 0.30
3.3
VCC
V
VCCO
Output Supply Voltage
3.135
3.3
3.465
V
ICC
Power Supply Current
273
mA
ICCA
Analog Supply Current
30
mA
ICCO
Output Supply Current
42
mA
Table 5E. LVDS Power Supply DC Characteristics, VCC = VCCO = 2.5V±5%, TA = -40°C to 85°C
Symbol
Parameter
Minimum
Typical
Maximum
Units
VCC
Core Supply Voltage
2.375
2.5
2.625
V
VCCA
Analog Supply Voltage
VCC – 0.26
2.5
VCC
V
VCCO
Output Supply Voltage
2.375
2.5
2.625
V
ICC
Power Supply Current
263
mA
ICCA
Analog Supply Current
26
mA
ICCO
Output Supply Current
42
mA
ICS849N202CKI REVISION A
Test Conditions
SEPTEMBER 26, 2011
14
©2011 Integrated Device Technology, Inc.
ICS849N202I Data Sheet
FemtoClock® NG Universal Frequency Translator
Table 5F. LVCMOS/LVTTL DC Characteristics, TA = -40°C to 85°C
Symbol
Parameter
VIH
Input High Voltage
VIL
Input Low Voltage
IIH
Input
High Current
Input
Low Current
IIL
Test Conditions
Minimum
VCC = 3.3V
Typical
Maximum
Units
2
VCC + 0.3
V
VCC = 2.5V
1.7
VCC + 0.3
V
VCC = 3.3V
-0.3
0.8
V
VCC = 2.5V
-0.3
0.7
V
CLK_SEL, CONFIG,
PLL_BYPASS, S_A[0:1]
VCC = VIN = 3.465V or 2.625V
150
µA
OE0, OE1,
SCLK, SDATA
VCC = VIN = 3.465V or 2.625V
5
µA
CLK_SEL, CONFIG,
PLL_BYPASS, S_A[0:1]
VCC = 3.465V or 2.625V,
VIN = 0V
-5
µA
OE0, OE1,
SCLK, SDATA
VCC = 3.465V or 2.625V,
VIN = 0V
-150
µA
VCCO = 3.3V ± 5%, IOH = -8mA
2.6
V
VCCO = 2.5V ± 5%, IOH = -8mA
1.8
V
VOH
Output
High Voltage
HOLDOVER, SDATA
CLK_ACTIVE,
LOCK_IND, XTALBAD,
CLK0BAD, CLK1BAD
VOL
Output
Low Voltage
HOLDOVER, SDATA
CLK_ACTIVE,
LOCK_IND, XTALBAD,
CLK0BAD, CLK1BAD
VCCO = 3.3V ± 5% or
2.5V ± 5%, IOL = 8mA
0.5
V
Table 5G. Differential DC Characteristics, VCC = VCCO = 3.3V±5% or 2.5V±5%, VEE = 0V, TA = -40°C to 85°C
Symbol
Parameter
IIH
Input
High Current
CLK0, nCLK0,
CLK1, nCLK1
IIL
Input
Low Current
CLK0, CLK1
VCC = 3.465V or 2.625V, VIN = 0V
-5
µA
nCLK0, nCLK1
VCC = 3.465V or 2.625V, VIN = 0V
-150
µA
VPP
Peak-to-Peak Voltage
VCMR
Common Mode Input Voltage;
NOTE 1
.NOTE
Test Conditions
Minimum
Typical
VCC = VIN = 3.465V or 2.625V
Maximum
Units
150
µA
0.15
1.3
V
VEE + 0.5
VCC - 1.0
V
Maximum
Units
1: Common mode input voltage is defined as the crosspoint voltage.
Table 5H. LVPECL DC Characteristics, VCC = VCCO = 3.3V±5%, VEE = 0V, TA = -40°C to 85°C
Symbol
Parameter
Test Conditions
Minimum
Typical
VOH
Output High Voltage; NOTE 1
VCCO – 1.1
VCCO – 0.7
V
VOL
Output Low Voltage NOTE 1
VCCO – 2.0
VCCO – 1.5
V
VSWING
Peak-to-Peak Output Voltage Swing
0.6
1.0
V
NOTE 1: Outputs terminated with 50Ω to VCCO – 2V.
ICS849N202CKI REVISION A
SEPTEMBER 26, 2011
15
©2011 Integrated Device Technology, Inc.
ICS849N202I Data Sheet
FemtoClock® NG Universal Frequency Translator
Table 5I. LVPECL DC Characteristics, VCC = 3.3V±5% or 2.5V±5%, VCCO = 2.5V±5%, VEE = 0V, TA = -40°C to 85°C
Symbol
Parameter
Test Conditions
VOH
Output High Voltage; NOTE 1
VOL
Output Low Voltage NOTE 1
VSWING
Peak-to-Peak Output Voltage Swing
Minimum
Typical
Maximum
Units
VCCO – 1.1
VCCO – 0.8
V
VCCO – 2.0
VCCO – 1.5
V
0.4
1.0
V
NOTE 1: Outputs terminated with 50Ω to VCCO – 2V.
Table 5J. LVDS DC Characteristics, VCC = VCCO = 3.3V ± 5%, TA = -40°C to 85°C
Symbol
Parameter
Test Conditions
VOD
Differential Output Voltage
∆VOD
VOD Magnitude Change
VOS
Offset Voltage
∆VOS
VOS Magnitude Change
Minimum
Typical
247
1.125
Maximum
Units
454
mV
50
mV
1.375
V
50
mV
Maximum
Units
454
mV
50
mV
1.375
V
50
mV
Table 5K. LVDS DC Characteristics, VCC = VCCO = 2.5V±5%, TA = -40°C to 85°C
Symbol
Parameter
Test Conditions
VOD
Differential Output Voltage
∆VOD
VOD Magnitude Change
VOS
Offset Voltage
∆VOS
VOS Magnitude Change
Minimum
Typical
247
1.125
Table 6. Input Frequency Characteristics, VCC = VCCO = 3.3V ± 5%, TA = -40°C to 85°C
Symbol
Parameter
Test Conditions
Maximum
Units
16
40
MHz
High Bandwidth Mode
16
710
MHz
Low Bandwidth Mode
0.008
710
MHz
5
MHz
XTAL_IN, XTAL_OUT
NOTE 1
fIN
Input
Frequency
CLK0, nCLK0,
CLK1, nCLK1
Minimum
Typical
SCLK
NOTE 1: For the input crystal and CLKx, nCLKx frequency range, the M value must be set for the VCO to operate within the 1995MHz to
2600MHz range.
Table 7. Crystal Characteristics
Parameter
Test Conditions
Minimum
Mode of Oscillation
Maximum
Units
40
MHz
100
Ω
7
pF
Fundamental
Frequency
16
Equivalent Series Resistance (ESR)
Shunt Capacitance
ICS849N202CKI REVISION A
Typical
SEPTEMBER 26, 2011
16
©2011 Integrated Device Technology, Inc.
ICS849N202I Data Sheet
FemtoClock® NG Universal Frequency Translator
AC Electrical Characteristics
Table 8. AC Characteristics, VCC = VCCO = 3.3V±5% or 2.5V±5%, or
VCC = 3.3V±5%, VCCO = 2.5V±5% (LVPECL Only), VEE = 0V, TA = -40°C to 85°C
Symbol
Parameter
fOUT
Output Frequency
tjit(Ø)
Test Conditions
Minimum
Typical
0.98
RMS Phase Jitter;
Integer Divide Ratio
Maximum
Units
1300
MHz
Synth Mode (Integer FB),
fOUT = 400MHz, 40MHz XTAL,
Integration Range: 12kHz – 40MHz
321
493
fs
Synth Mode (FracN FB),
fOUT = 698.81MHz, 40MHz XTAL,
Integration Range: 12kHz – 20MHz
469
638
fs
HBW Mode, (NOTE 1)
fIN = 133.33MHz, fOUT = 400MHz,
Integration Range: 12kHz – 20MHz
301
428
fs
LBW Mode (FracN), 40MHz XTAL,
fIN = 19.44MHz, fOUT = 622.08MHz,
Integration Range: 12kHz – 20MHz
477
600
fs
LBW Mode (FracN), 40MHz XTAL,
fIN = 25MHz, fOUT = 125MHz,
Integration Range: 12kHz – 20MHz
510
618
fs
Frequency Synthesizer Mode
50
ps
Frequency Translator Mode
40
ps
30
ps
3.7
ps
tjit(cc)
Cycle-to-Cycle Jitter; NOTE 2
tsk(o)
Output Skew; NOTE 2, 3
tjit(per)
RMS Period
Jitter
LVPECL Outputs
7.5
ps
tR / tF
Output
Rise/Fall Time
LVPECL Outputs
20% to 80%
80
500
ps
LVDS Outputs
20% to 80%
100
500
ps
odc
Output Duty Cycle
fOUT < 600MHz
47
53
%
fOUT ≥ 600MHz
45
55
%
tSET
2.1
LVDS Outputs
Output Re-configuration Settling
Time
4.7
from falling edge of the 8th SCLK for a
register change
200
ns
from edge on CONFIG pin
10
ns
NOTE: Electrical parameters are guaranteed over the specified ambient operating temperature range, which is established when the device is
mounted in a test socket with maintained transverse airflow greater than 500 lfpm. The device will meet specifications after thermal equilibrium
has been reached under these conditions.
NOTE 1: Measured using a Rohde & Schwarz SMA100 Signal Generator, 9kHz to 6GHz as the input source.
NOTE 2: This parameter is defined in accordance with JEDEC Standard 65.
NOTE 3: Defined as skew between outputs at the same supply voltage and with equal load conditions. Measured at the output differential cross
points.
ICS849N202CKI REVISION A
SEPTEMBER 26, 2011
17
©2011 Integrated Device Technology, Inc.
ICS849N202I Data Sheet
FemtoClock® NG Universal Frequency Translator
Typical Phase Noise at 400MHz (HBW Mode)
Noise Power
dBc
Hz
400MHz
RMS Phase Jitter
12kHz to 20MHz = 295fs (typical)
Offset Frequency (Hz)
ICS849N202CKI REVISION A
SEPTEMBER 26, 2011
18
©2011 Integrated Device Technology, Inc.
ICS849N202I Data Sheet
FemtoClock® NG Universal Frequency Translator
Parameter Measurement Information
2V
2V
2V
VCC,
VCCO
2V
Qx
SCOPE
VCC,
VCCO
VCCA
Qx
SCOPE
VCCA
nQx
nQx
VEE
VEE
-1.3V+0.165V
-0.5V±0.125V
2.5 Core/2.5V LVPECL Output Load AC Test Circuit
3.3 Core/3.3V LVPECL Output Load AC Test Circuit
2.8V±0.04V
2V
2.8V±0.04V
VCC
Qx
VCCO
SCOPE
SCOPE
VCC,
VCCO VCCA
3.3V±5%
POWER SUPPLY
+ Float GND –
VCCA
Qx
nQx
nQx
VEE
-0.5V±0.125V
3.3 Core/3.3V LVDS Output Load AC Test Circuit
3.3 Core/2.5V LVPECL Output Load AC Test Circuit
VCC
SCOPE
VCC,
2.5V±5%
POWER SUPPLY
+ Float GND –
Qx
nCLKx
VCCO V
CCA
V
PP
Cross Points
CLKx
nQx
V
CMR
VEE
2.5 Core/2.5V LVDS Output Load AC Test Circuit
ICS849N202CKI REVISION A
SEPTEMBER 26, 2011
Differential Input Levels
19
©2011 Integrated Device Technology, Inc.
ICS849N202I Data Sheet
FemtoClock® NG Universal Frequency Translator
Parameter Measurement Information, continued
Phase Noise Plot
Noise Power
nQx
Qx
nQy
Qy
f1
Offset Frequency
tsk(o)
f2
RMS Jitter = Area Under Curve Defined by the Offset Frequency Markers
Output Skew
RMS Phase Jitter
VOH
nQx
VREF
Qx
➤
➤
tcycle n
tcycle n+1
VOL
1σ contains 68.26% of all measurements
2σ contains 95.4% of all measurements
3σ contains 99.73% of all measurements
4σ contains 99.99366% of all measurements
6σ contains (100-1.973x10-7)% of all measurements
➤
➤
tjit(cc) = |tcycle n – tcycle n+1|
1000 Cycles
Histogram
Reference Point
Mean Period
(Trigger Edge)
(First edge after trigger)
Period Jitter
Cycle-to-Cycle Jitter
nQx
nQx
80%
80%
80%
80%
VSW I N G
VOD
Qx
20%
20%
Qx
SEPTEMBER 26, 2011
tF
LVPECL Output Rise/Fall Time
LVDS Output Rise/Fall Time
ICS849N202CKI REVISION A
20%
20%
tR
tF
tR
20
©2011 Integrated Device Technology, Inc.
ICS849N202I Data Sheet
FemtoClock® NG Universal Frequency Translator
Parameter Measurement Information, continued
VDD
nQx
out
Qx
t
odc =
DC Input
PERIOD
t PW
LVDS
➤
t PW
out
x 100%
t PERIOD
➤
VOS/∆ VOS
➤
Differential Output Duty Cycle/Output Pulse Width/Period
Offset Voltage Setup
VDD
LVDS
100
➤
VOD/∆ VOD
out
➤
DC Input
➤
out
Differential Output Voltage Setup
ICS849N202CKI REVISION A
SEPTEMBER 26, 2011
21
©2011 Integrated Device Technology, Inc.
ICS849N202I Data Sheet
FemtoClock® NG Universal Frequency Translator
Applications Information
Recommendations for Unused Input and Output Pins
Inputs:
Outputs:
Crystal Inputs
LVPECL Outputs
For applications not requiring the use of the crystal oscillator input,
both XTAL_IN and XTAL_OUT can be left floating. Though not
required, but for additional protection, a 1kΩ resistor can be tied from
XTAL_IN to ground.
All unused LVPECL outputs can be left floating. We recommend that
there is no trace attached. Both sides of the differential output pair
should either be left floating or terminated.
CLKx/nCLKx Inputs
All unused LVDS output pairs can be either left floating or terminated
with 100Ω across. If they are left floating there should be no trace
attached.
LVDS Outputs
For applications not requiring the use of either differential input, both
CLKx and nCLKx can be left floating. Though not required, but for
additional protection, a 1kΩ resistor can be tied from CLKx to ground.
It is recommended that CLKx, nCLKx be left unconnected in
frequency synthesizer mode.
LVCMOS Outputs
All unused LVCMOS output can be left floating. There should be no
trace attached.
LVCMOS Control Pins
All control pins have internal pullups or pulldowns; additional
resistance is not required but can be added for additional protection.
A 1kΩ resistor can be used.
Recommended Values for Low-Bandwidth Mode Loop Filter
External loop filter components are not needed in Frequency
Synthesizer or High-Bandwidth modes. In Low-Bandwidth mode, the
loop filter structure and components shown in Figure 11 are
recommended. Please consult IDT if other values are needed.
ICS849N202CKI REVISION A
SEPTEMBER 26, 2011
22
©2011 Integrated Device Technology, Inc.
ICS849N202I Data Sheet
FemtoClock® NG Universal Frequency Translator
Wiring the Differential Input to Accept Single-Ended Levels
Figure 4 shows how a differential input can be wired to accept single
ended levels. The reference voltage VREF = VCC/2 is generated by
the bias resistors R1 and R2. The bypass capacitor (C1) is used to
help filter noise on the DC bias. This bias circuit should be located as
close to the input pin as possible. The ratio of R1 and R2 might need
to be adjusted to position the VREF in the center of the input voltage
swing. For example, if the input clock swing is 2.5V and VCC = 3.3V,
R1 and R2 value should be adjusted to set VREF at 1.25V. The values
below are for when both the single ended swing and VCC are at the
same voltage. This configuration requires that the sum of the output
impedance of the driver (Ro) and the series resistance (Rs) equals
the transmission line impedance. In addition, matched termination at
the input will attenuate the signal in half. This can be done in one of
two ways. First, R3 and R4 in parallel should equal the transmission
line impedance. For most 50Ω applications, R3 and R4 can be 100Ω.
The values of the resistors can be increased to reduce the loading for
slower and weaker LVCMOS driver. When using single-ended
signaling, the noise rejection benefits of differential signaling are
reduced. Even though the differential input can handle full rail
LVCMOS signaling, it is recommended that the amplitude be
reduced. The datasheet specifies a lower differential amplitude,
however this only applies to differential signals. For single-ended
applications, the swing can be larger, however VIL cannot be less
than -0.3V and VIH cannot be more than VCC + 0.3V. Though some
of the recommended components might not be used, the pads
should be placed in the layout. They can be utilized for debugging
purposes. The datasheet specifications are characterized and
guaranteed by using a differential signal.
Figure 4. Recommended Schematic for Wiring a Differential Input to Accept Single-ended Levels
ICS849N202CKI REVISION A
SEPTEMBER 26, 2011
23
©2011 Integrated Device Technology, Inc.
ICS849N202I Data Sheet
FemtoClock® NG Universal Frequency Translator
Overdriving the XTAL Interface
The XTAL_IN input can be overdriven by an LVCMOS driver or by one
side of a differential driver through an AC coupling capacitor. The
XTAL_OUT pin can be left floating. The amplitude of the input signal
should be between 500mV and 1.8V and the slew rate should not be
less than 0.2V/nS. For 3.3V LVCMOS inputs, the amplitude must be
reduced from full swing to at least half the swing in order to prevent
signal interference with the power rail and to reduce internal noise.
Figure 5A shows an example of the interface diagram for a high
speed 3.3V LVCMOS driver. This configuration requires that the sum
of the output impedance of the driver (Ro) and the series resistance
(Rs) equals the transmission line impedance. In addition, matched
termination at the crystal input will attenuate the signal in half. This
VCC
can be done in one of two ways. First, R1 and R2 in parallel should
equal the transmission line impedance. For most 50Ω applications,
R1 and R2 can be 100Ω. This can also be accomplished by removing
R1 and changing R2 to 50Ω. The values of the resistors can be
increased to reduce the loading for a slower and weaker LVCMOS
driver. Figure 5B shows an example of the interface diagram for an
LVPECL driver. This is a standard LVPECL termination with one side
of the driver feeding the XTAL_IN input. It is recommended that all
components in the schematics be placed in the layout. Though some
components might not be used, they can be utilized for debugging
purposes. The datasheet specifications are characterized and
guaranteed by using a quartz crystal as the input.
XTAL_OUT
R1
100
Ro
Rs
C1
Zo = 50 ohms
XTAL_IN
R2
100
Zo = Ro + Rs
.1uf
LVCMOS Driver
Figure 5A. General Diagram for LVCMOS Driver to XTAL Input Interface
XTAL_OUT
C2
Zo = 50 ohms
XTAL_IN
.1uf
Zo = 50 ohms
LVPECL Driver
R1
50
R2
50
R3
50
Figure 5B. General Diagram for LVPECL Driver to XTAL Input Interface
ICS849N202CKI REVISION A
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24
©2011 Integrated Device Technology, Inc.
ICS849N202I Data Sheet
FemtoClock® NG Universal Frequency Translator
Differential Clock Input Interface
with the vendor of the driver component to confirm the driver
termination requirements. For example, in Figure 6A, the input
termination applies for IDT open emitter LVHSTL drivers. If you are
using an LVHSTL driver from another vendor, use their termination
recommendation.
The CLK /nCLK accepts LVDS, LVPECL, LVHSTL, HCSL and other
differential signals. Both VSWING and VOH must meet the VPP and
VCMR input requirements. Figures 6A to 6E show interface examples
for the CLK/nCLK input driven by the most common driver types. The
input interfaces suggested here are examples only. Please consult
3.3V
3.3V
3.3V
1.8V
Zo = 50Ω
Zo = 50Ω
CLK
CLK
Zo = 50Ω
Zo = 50Ω
nCLK
nCLK
Differential
Input
LVHSTL
R1
50Ω
IDT
LVHSTL Driver
Differential
Input
LVPECL
R2
50Ω
R1
50Ω
R2
50Ω
R2
50Ω
Figure 6A. CLK/nCLK Input
Driven by an IDT Open Emitter LVHSTL Driver
Figure 6B. CLK/nCLK Input
Driven by a 3.3V LVPECL Driver
3.3V
3.3V
3.3V
R3
125Ω
3.3V
R4
125Ω
3.3V
Zo = 50Ω
Zo = 50Ω
CLK
CLK
R1
100Ω
Zo = 50Ω
nCLK
R1
84Ω
Zo = 50Ω
Differential
Input
LVPECL
R2
84Ω
3.3V
Receiver
LVDS
Figure 6C. CLK/nCLK Input
Driven by a 3.3V LVPECL Driver
nCLK
Figure 6D. CLK/nCLK Input
Driven by a 3.3V LVDS Driver
3.3V
*R3
33Ω
Zo = 50Ω
CLK
Zo = 50Ω
nCLK
HCSL
*R4
33Ω
R1
50Ω
R2
50Ω
Differential
Input
*Optional – R3 and R4 can be 0Ω
Figure 6E. CLK/nCLK Input
Driven by a 3.3V HCSL Driver
ICS849N202CKI REVISION A
SEPTEMBER 26, 2011
25
©2011 Integrated Device Technology, Inc.
ICS849N202I Data Sheet
FemtoClock® NG Universal Frequency Translator
LVDS Driver Termination
For a general LVDS interface, the recommended value for the
termination impedance (ZT) is between 90Ω and 132Ω. The actual
value should be selected to match the differential impedance (Z0) of
your transmission line. A typical point-to-point LVDS design uses a
100Ω parallel resistor at the receiver and a 100Ω differential
transmission-line environment. In order to avoid any
transmission-line reflection issues, the components should be
surface mounted and must be placed as close to the receiver as
possible. IDT offers a full line of LVDS compliant devices with two
types of output structures: current source and voltage source. The
LVDS
Driver
standard termination schematic as shown in Figure 7A can be used
with either type of output structure. Figure 7B, which can also be
used with both output types, is an optional termination with center tap
capacitance to help filter common mode noise. The capacitor value
should be approximately 50pF. If using a non-standard termination, it
is recommended to contact IDT and confirm if the output structure is
current source or voltage source type. In addition, since these
outputs are LVDS compatible, the input receiver’s amplitude and
common-mode input range should be verified for compatibility with
the output.
ZO • Z T
ZT
LVDS
Receiver
Figure 7A. Standard Termination
LVDS
Driver
Z O • ZT
C
ZT
2 LVDS
ZT Receiver
2
Figure 7B. Optional Termination
ICS849N202CKI REVISION A
SEPTEMBER 26, 2011
26
©2011 Integrated Device Technology, Inc.
ICS849N202I Data Sheet
FemtoClock® NG Universal Frequency Translator
Termination for 3.3V LVPECL Outputs
The clock layout topology shown below is a typical termination for
LVPECL outputs. The two different layouts mentioned are
recommended only as guidelines.
transmission lines. Matched impedance techniques should be used
to maximize operating frequency and minimize signal distortion.
Figures 8A and 8B show two different layouts which are
recommended only as guidelines. Other suitable clock layouts may
exist and it would be recommended that the board designers
simulate to guarantee compatibility across all printed circuit and clock
component process variations.
The differential outputs are low impedance follower outputs that
generate ECL/LVPECL compatible outputs. Therefore, terminating
resistors (DC current path to ground) or current sources must be
used for functionality. These outputs are designed to drive 50Ω
R3
125Ω
3.3V
3.3V
Zo = 50Ω
3.3V
R4
125Ω
3.3V
3.3V
+
Zo = 50Ω
+
_
LVPECL
Input
Zo = 50Ω
R1
50Ω
_
LVPECL
R2
50Ω
R1
84Ω
VCC - 2V
RTT =
1
* Zo
((VOH + VOL) / (VCC – 2)) – 2
R2
84Ω
RTT
Figure 8A. 3.3V LVPECL Output Termination
ICS849N202CKI REVISION A
Input
Zo = 50Ω
SEPTEMBER 26, 2011
Figure 8B. 3.3V LVPECL Output Termination
27
©2011 Integrated Device Technology, Inc.
ICS849N202I Data Sheet
FemtoClock® NG Universal Frequency Translator
Termination for 2.5V LVPECL Outputs
level. The R3 in Figure 10B can be eliminated and the termination is
shown in Figure 10C.
Figure 10A and Figure 10B show examples of termination for 2.5V
LVPECL driver. These terminations are equivalent to terminating 50Ω
to VCCO – 2V. For VCCO = 2.5V, the VCCO – 2V is very close to ground
2.5V
VCCO = 2.5V
2.5V
2.5V
VCCO = 2.5V
R1
250
R3
250
50Ω
+
50Ω
+
50Ω
–
50Ω
2.5V LVPECL Driver
–
R1
50
2.5V LVPECL Driver
R2
62.5
R2
50
R4
62.5
R3
18
Figure 9A. 2.5V LVPECL Driver Termination Example
Figure 9B. 2.5V LVPECL Driver Termination Example
2.5V
VCCO = 2.5V
50Ω
+
50Ω
–
2.5V LVPECL Driver
R1
50
R2
50
Figure 9C. 2.5V LVPECL Driver Termination Example
ICS849N202CKI REVISION A
SEPTEMBER 26, 2011
28
©2011 Integrated Device Technology, Inc.
ICS849N202I Data Sheet
FemtoClock® NG Universal Frequency Translator
VFQFN EPAD Thermal Release Path
In order to maximize both the removal of heat from the package and
the electrical performance, a land pattern must be incorporated on
the Printed Circuit Board (PCB) within the footprint of the package
corresponding to the exposed metal pad or exposed heat slug on the
package, as shown in Figure 10. The solderable area on the PCB, as
defined by the solder mask, should be at least the same size/shape
as the exposed pad/slug area on the package to maximize the
thermal/electrical performance. Sufficient clearance should be
designed on the PCB between the outer edges of the land pattern
and the inner edges of pad pattern for the leads to avoid any shorts.
and dependent upon the package power dissipation as well as
electrical conductivity requirements. Thus, thermal and electrical
analysis and/or testing are recommended to determine the minimum
number needed. Maximum thermal and electrical performance is
achieved when an array of vias is incorporated in the land pattern. It
is recommended to use as many vias connected to ground as
possible. It is also recommended that the via diameter should be 12
to 13mils (0.30 to 0.33mm) with 1oz copper via barrel plating. This is
desirable to avoid any solder wicking inside the via during the
soldering process which may result in voids in solder between the
exposed pad/slug and the thermal land. Precautions should be taken
to eliminate any solder voids between the exposed heat slug and the
land pattern. Note: These recommendations are to be used as a
guideline only. For further information, please refer to the Application
Note on the Surface Mount Assembly of Amkor’s Thermally/
Electrically Enhance Lead frame Base Package, Amkor Technology.
While the land pattern on the PCB provides a means of heat transfer
and electrical grounding from the package to the board through a
solder joint, thermal vias are necessary to effectively conduct from
the surface of the PCB to the ground plane(s). The land pattern must
be connected to ground through these vias. The vias act as “heat
pipes”. The number of vias (i.e. “heat pipes”) are application specific
PIN
PIN PAD
SOLDER
EXPOSED HEAT SLUG
GROUND PLANE
THERMAL VIA
SOLDER
LAND PATTERN
(GROUND PAD)
PIN
PIN PAD
Figure 10. P.C. Assembly for Exposed Pad Thermal Release Path – Side View (drawing not to scale)
ICS849N202CKI REVISION A
SEPTEMBER 26, 2011
29
©2011 Integrated Device Technology, Inc.
ICS849N202I Data Sheet
FemtoClock® NG Universal Frequency Translator
Schematic Layout
In order to achieve the best possible filtering, it is recommended that
the placement of the filter components be on the device side of the
PCB as close to the power pins as possible. If space is limited, the
0.1uf capacitor in each power pin filter should be placed on the
device side. The other components can be on the opposite side of
the PCB.
Figure 11 (next page), shows an example of the UFT (849N202I)
application schematic. Input and output terminations shown are
intended as examples only and may not represent the exact user
configuration. In this example, the device is operated at VCC = 3.3V.
For 2.5V option, please refer to the “Termination for 2.5V LVPECL
Outputs” for output termination recommendation. The decoupling
capacitors should be located as close as possible to the power pin.
A 12pF parallel resonant 16MHz to 40MHz crystal is used in this
example. Different crystal frequencies may be used. The C1 = C2 =
5pF are recommended for frequency accuracy. If different crystal
types are used, please consult IDT for recommendations. For
different board layout, the C1 and C2 may be slightly adjusted for
optimizing frequency accuracy. It is recommended that the loop filter
components be laid out for the 3-pole option. This will also allow
either 2-pole or 3-pole filter to be used. The 3-pole filter can be used
for additional spur reduction. If a 2-pole filter construction is used,
the LF0 and LF1 pins must be tied-together to the filter.
Power supply filter recommendations are a general guideline to be
used for reducing external noise from coupling into the devices. The
filter performance is designed for a wide range of noise frequencies.
This low-pass filter starts to attenuate noise at approximately 10
kHz. If a specific frequency noise component is known, such as
switching power supplies frequencies, it is recommended that
component values be adjusted and if required, additional filtering be
added. Additionally, good general design practices for power plane
voltage stability suggests adding bulk capacitance in the local area
of all devices.
The schematic example focuses on functional connections and is not
configuration specific. Refer to the pin description and functional
tables in the datasheet to ensure the logic control inputs are properly
set
As with any high speed analog circuitry, the power supply pins are
vulnerable to random noise. To achieve optimum jitter performance,
power supply isolation is required. The UFT (849N202I) provides
separate power supplies to isolate any high switching noise from
coupling into the internal PLL.
ICS849N202CKI REVISION A
SEPTEMBER 26, 2011
30
©2011 Integrated Device Technology, Inc.
ICS849N202I Data Sheet
FemtoClock® NG Universal Frequency Translator
3.3V
FB1
VDDO
muRata, BLM18BB221SN1
C13
0.1uF
3.3V
Output Termination Example - LVDS
output shown (Note 3)
C14
C15
VDD
10uF
0.1uF
C4
C5
C6
C7
0.1uF
0.1uF
0.1uF
0.1uF
FB2
Zo = Zo_Dif f = 100-ohm
VDD
muRata, BLM18BB221SN1
C8
0.1uF
C9
C10
10uF
0.1uF
R2 10
C11
C12
R1
10uF
0.1uF
100
+
CLK0
Input Termination
Example - LVDS input
shown (Note 3)
R5
(Note 1)
(Note 2)CLK_SEL
(Note
(Note
(Note
(Note
100
nCLK0
1)
2)PLL_BYPASS
1)S_A0
1)S_A1
SCLK
SDATA
(Note 1)CONFIG
VDD
125
R11
4.7K
nCLK1
2-pole loop filter - (optional)
LF1
LF0
0.001uF
R10
125
CLK1
Input Termination
Example - LVPECL
input shown (Note 3)
Cp
R9
8
21
35
(Note 2)
R14
R15
84
84
Set Logic
Input to '1'
Cs
1uF
Not Installed
36
1)
Zo = 50-ohm
Set Logic
Input to '0'
VDD
To Logic
Input pins
Rs
R17
R4
125
125
+
Zo = 50-ohm
-
3-pole loop filter
0.001uF
RU2
Not Installed
RD1
OE1(Note
VDDO
LOCK_IND
CLK_ACTIVE
HOLDOVER
CLKBAD
CLK1BAD
XTALBAD
Cp
To Logic
Input pins
470K
1)
R6
R7
84
84
C3
0.001uF
220K
R12
4.7K
Logic Input Pin Examples
VDD
OE0(Note
R3
VDD
RU1
1K
Rs
UFT
VEE
VEE
VEE
5pF
1
2 XTAL_IN
XTAL_OUT
4
5 CLK_SEL
6 CLK0
9 CLK0
10 CLK1
CLK1
12
18 PLL_BYPASS
17 S_A0
15 S_A1
14 SCLK
16 SDATA
CONFIG
nc
nc
nc
nc
C2
27
Q0 26
Q0 28
OE0
24
Q1 23
Q1 22
OE1
30
LOCK_IND 31
CLK_ACTIVE 37
HOLDOVER 38
CLK0BAD 39
CLK1BAD 40
XTALBAD
34
LF1
33
LF0
VC C A
X1
19
20
11
32
F
p
2
1
5pF
U1
VC C O
VC C
VC C
VC C
VC C
16MHz to 40 MHz
25
3
7
13
29
C1
Output Termination Example - LVPECL
output shown (Note 3)
470K
Cs
1uF
Notes
Note 1: CE0, OE1, CLK_SEL, PLL_BYPASS, S_A0 and S_A1 are digital control inputs. If
external pull-up/down needed, see "Logic Input Pin Examples" shown at left. Please note
that OE0 and OE1 are internally pulled up so no external pull-ups are required to enable
them.
Note 2: CLK_SEL, PLL_BYPASS and CONFIG are internally pulled down. No external
compononents required to select default condition.
Note 3: Other configurations are supported. Please contact IDT for details.
RD2
1K
Figure 11. ICS849N202I Application Schematic
ICS849N202CKI REVISION A
SEPTEMBER 26, 2011
31
©2011 Integrated Device Technology, Inc.
ICS849N202I Data Sheet
FemtoClock® NG Universal Frequency Translator
Power Considerations (3.3V LVPECL Outputs)
This section provides information on power dissipation and junction temperature for the ICS849N202I.
Equations and example calculations are also provided.
1.
Power Dissipation.
The total power dissipation for the ICS849N202I is the sum of the core power plus the power dissipated in the load(s).
The following is the power dissipation for VCC = 3.3V + 5% = 3.465V, which gives worst case results.
NOTE: Please refer to Section 3 for details on calculating power dissipated in the load.
•
Power (core)MAX = VCC_MAX * IEE_MAX = 3.465V * 320mA = 1108.8mW
•
Power (outputs)MAX = 33.2mW/Loaded Output pair
If all outputs are loaded, the total power is 2 * 33.2mW = 66.4mW
Total Power_MAX (3.465V, with all outputs switching) = 1108.8mW + 66.4mW = 1175.2mW
2. Junction Temperature.
Junction temperature, Tj, is the temperature at the junction of the bond wire and bond pad directly affects the reliability of the device. The
maximum recommended junction temperature is 125°C. Limiting the internal transistor junction temperature, Tj, to 125°C ensures that the bond
wire and bond pad temperature remains below 125°C.
The equation for Tj is as follows: Tj = θJA * Pd_total + TA
Tj = Junction Temperature
θJA = Junction-to-Ambient Thermal Resistance
Pd_total = Total Device Power Dissipation (example calculation is in section 1 above)
TA = Ambient Temperature
In order to calculate junction temperature, the appropriate junction-to-ambient thermal resistance θJA must be used. Assuming no air flow and
a multi-layer board, the appropriate value is 32.4°C/W per Table 9 below.
Therefore, Tj for an ambient temperature of 85°C with all outputs switching is:
85°C + 1.175W * 32.4°C/W = 123.1°C. This is below the limit of 125°C.
This calculation is only an example. Tj will obviously vary depending on the number of loaded outputs, supply voltage, air flow and the type of
board (multi-layer).
Table 9. Thermal Resistance θJA for 40 Lead VFQFN, Forced Convection
θJA by Velocity
Meters per Second
Multi-Layer PCB, JEDEC Standard Test Boards
ICS849N202CKI REVISION A
SEPTEMBER 26, 2011
0
1
2.5
32.4°C/W
25.7°C/W
23.4°C/W
32
©2011 Integrated Device Technology, Inc.
ICS849N202I Data Sheet
FemtoClock® NG Universal Frequency Translator
3. Calculations and Equations.
The purpose of this section is to calculate the power dissipation for the LVPECL output pairs.
LVPECL output driver circuit and termination are shown in Figure 12.
VCCO
Q1
VOUT
RL
50Ω
VCCO - 2V
Figure 12. LVPECL Driver Circuit and Termination
To calculate worst case power dissipation into the load, use the following equations which assume a 50Ω load, and a termination voltage of
VCCO – 2V.
•
For logic high, VOUT = VOH_MAX = VCCO_MAX – 0.7V
(VCCO_MAX – VOH_MAX) = 0.7V
•
For logic low, VOUT = VOL_MAX = VCCO_MAX – 1.5V
(VCCO_MAX – VOL_MAX) = 1.5V
Pd_H is power dissipation when the output drives high.
Pd_L is the power dissipation when the output drives low.
Pd_H = [(VOH_MAX – (VCCO_MAX – 2V))/RL] * (VCCO_MAX – VOH_MAX) = [(2V – (VCCO_MAX – VOH_MAX))/RL] * (VCCO_MAX – VOH_MAX) =
[(2V – 0.7V)/50Ω] * 0.7V = 18.2mW
Pd_L = [(VOL_MAX – (VCCO_MAX – 2V))/RL] * (VCCO_MAX – VOL_MAX) = [(2V – (VCCO_MAX – VOL_MAX))/RL] * (VCCO_MAX – VOL_MAX) =
[(2V – 1.5V)/50Ω] * 1.5V = 15mW
Total Power Dissipation per output pair = Pd_H + Pd_L = 33.2mW
ICS849N202CKI REVISION A
SEPTEMBER 26, 2011
33
©2011 Integrated Device Technology, Inc.
ICS849N202I Data Sheet
FemtoClock® NG Universal Frequency Translator
Power Considerations (LVDS Outputs)
This section provides information on power dissipation and junction temperature for the ICS849N202I.
Equations and example calculations are also provided.
1.
Power Dissipation.
The total power dissipation for the ICS849N202I is the sum of the core power plus the power dissipated in the load(s).
The following is the power dissipation for VCC = 3.3V + 5% = 3.465V, which gives worst case results.
NOTE: Please refer to Section 3 for details on calculating power dissipated in the load.
•
Power (core)MAX = VCC_MAX * (ICC_MAX + ICCA_MAX) = 3.465V * (273mA + 30mA) = 1049.895mW
•
Power (outputs)MAX = VCCO_MAX * ICCO_MAX = 3.465V * 42mA = 145.53mW
Total Power_MAX = 1049.895mW + 145.53mW = 1195.425mW
2. Junction Temperature.
Junction temperature, Tj, is the temperature at the junction of the bond wire and bond pad directly affects the reliability of the device. The
maximum recommended junction temperature is 125°C. Limiting the internal transistor junction temperature, Tj, to 125°C ensures that the bond
wire and bond pad temperature remains below 125°C.
The equation for Tj is as follows: Tj = θJA * Pd_total + TA
Tj = Junction Temperature
θJA = Junction-to-Ambient Thermal Resistance
Pd_total = Total Device Power Dissipation (example calculation is in section 1 above)
TA = Ambient Temperature
In order to calculate junction temperature, the appropriate junction-to-ambient thermal resistance θJA must be used. Assuming no air flow and
a multi-layer board, the appropriate value is 32.4°C/W per Table 10 below.
Therefore, Tj for an ambient temperature of 85°C with all outputs switching is:
85°C + 1.195W * 32.4°C/W = 123.7°C. This is below the limit of 125°C.
This calculation is only an example. Tj will obviously vary depending on the number of loaded outputs, supply voltage, air flow and the type of
board (multi-layer).
Table 10. Thermal Resistance θJA for 40 Lead VFQFN, Forced Convection
θJA by Velocity
Meters per Second
Multi-Layer PCB, JEDEC Standard Test Boards
ICS849N202CKI REVISION A
SEPTEMBER 26, 2011
0
1
2.5
32.4°C/W
25.7°C/W
23.4°C/W
34
©2011 Integrated Device Technology, Inc.
ICS849N202I Data Sheet
FemtoClock® NG Universal Frequency Translator
Reliability Information
Table 11. θJA vs. Air Flow Table for a 40 Lead VFQFN
θJA vs. Air Flow
Meters per Second
Multi-Layer PCB, JEDEC Standard Test Boards
0
1
2.5
32.4°C/W
25.7°C/W
23.4°C/W
Transistor Count
The transistor count for ICS849N202I is: 50,610
ICS849N202CKI REVISION A
SEPTEMBER 26, 2011
35
©2011 Integrated Device Technology, Inc.
ICS849N202I Data Sheet
FemtoClock® NG Universal Frequency Translator
Package Outline and Package Dimensions
Package Outline - K Suffix for 40 Lead VFQFN
(Ref.)
S eating Plan e
N &N
Even
(N -1)x e
(R ef.)
A1
Ind ex Area
A3
N
Anvil
Anvil
Singulation
Singula tion
or
OR
Sawn
Singulation
To p View
L
N
e (Ty p.)
2 If N & N
1
are Even
2
E2
(N -1)x e
(Re f.)
E2
2
b
A
(Ref.)
D
e
N &N
Odd
0. 08
Chamfer 4x
0.6 x 0.6 max
OPTIONAL
C
D2
C
Bottom View w/Type A ID
Bottom View w/Type C ID
2
1
2
1
CHAMFER
4
Th er mal
Ba se
D2
2
N N-1
RADIUS
4
N N-1
There are 2 methods of indicating pin 1 corner at the back of the VFQFN package are:
1. Type A: Chamfer on the paddle (near pin 1)
2. Type C: Mouse bite on the paddle (near pin 1)
Table 12. Package Dimensions
NOTE: The following package mechanical drawing is a generic
drawing that applies to any pin count VFQFN package. This drawing
is not intended to convey the actual pin count or pin layout of this
device. The pin count and pinout are shown on the front page. The
package dimensions are in Table 12 below
JEDEC Variation: VJJD-2/-5
All Dimensions in Millimeters
Symbol
Minimum
Maximum
N
40
A
0.80
1.00
A1
0
0.05
A3
0.25 Ref.
b
0.18
0.30
10
ND & NE
D&E
6.00 Basic
D2 & E2
4.55
4.75
e
0.50 Basic
L
0.30
0.50
Reference Document: JEDEC Publication 95, MO-220
ICS849N202CKI REVISION A
SEPTEMBER 26, 2011
36
©2011 Integrated Device Technology, Inc.
ICS849N202I Data Sheet
FemtoClock® NG Universal Frequency Translator
Ordering Information
Table 13. Ordering Information
Part/Order Number
Marking
Package
Shipping Packaging
Temperature
849N202CKI-dddLF
ICS9202CIddd
“Lead-Free” 40 Lead VFQFN
Tray
-40°C to +85°C
849N202CKI-dddLFT
ICS9202CIddd
“Lead-Free” 40 Lead VFQFN
2500 Tape & Reel
-40°C to +85°C
NOTE: Parts that are ordered with an “LF” suffix to the part number are the Pb-Free configuration and are RoHS compliant.
NOTE: For the specific -ddd order codes, refer to FemtoClock NG Universal Frequency Translator Ordering Product Information document.
While the information presented herein has been checked for both accuracy and reliability, Integrated Device Technology (IDT) assumes no responsibility for either its use or for the
infringement of any patents or other rights of third parties, which would result from its use. No other circuits, patents, or licenses are implied. This product is intended for use in normal
commercial and industrial applications. Any other applications, such as those requiring high reliability or other extraordinary environmental requirements are not recommended without
additional processing by IDT. IDT reserves the right to change any circuitry or specifications without notice. IDT does not authorize or warrant any IDT product for use in life support
devices or critical medical instruments.
ICS849N202CKI REVISION A
SEPTEMBER 26, 2011
37
©2011 Integrated Device Technology, Inc.
ICS849N202I Data Sheet
FemtoClock® NG Universal Frequency Translator
Revision History Sheet
Rev
Table
Page
A
ICS849N202CKI REVISION A
18
Description of Change
Date
Phase Jitter Plot Label - corrected integration range from 12MHz to 12kHz.
SEPTEMBER 26, 2011
38
9/26/11
©2011 Integrated Device Technology, Inc.
ICS849N202I Data Sheet
FemtoClock® NG Universal Frequency Translator
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800-345-7015 (inside USA)
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[email protected]
+480-763-2056
DISCLAIMER Integrated Device Technology, Inc. (IDT) and its subsidiaries reserve the right to modify the products and/or specifications described herein at any time and at IDT’s sole discretion. All information in this document,
including descriptions of product features and performance, is subject to change without notice. Performance specifications and the operating parameters of the described products are determined in the independent state and are not
guaranteed to perform the same way when installed in customer products. The information contained herein is provided without representation or warranty of any kind, whether express or implied, including, but not limited to, the
suitability of IDT’s products for any particular purpose, an implied warranty of merchantability, or non-infringement of the intellectual property rights of others. This document is presented only as a guide and does not convey any
license under intellectual property rights of IDT or any third parties.
IDT’s products are not intended for use in life support systems or similar devices where the failure or malfunction of an IDT product can be reasonably expected to significantly affect the health or safety of users. Anyone using an IDT
product in such a manner does so at their own risk, absent an express, written agreement by IDT.
Integrated Device Technology, IDT and the IDT logo are registered trademarks of IDT. Other trademarks and service marks used herein, including protected names, logos and designs, are the property of IDT or their respective third
party owners.
Copyright 2011. All rights reserved.