IDT8T49N222I Datasheet, PDF (1/40 Pages) Integrated Device Technology – Fourth generation FemtoClock

DATA SHEET
FemtoClock® NG Universal Frequency
Translator
IDT8T49N222I
General Description
The IDT8T49N222I is a highly flexible FemtoClock® NG general
purpose, low phase noise Frequency Translator / Synthesizer with
alarm and monitoring functions suitable for networking and
communications applications. It is able to generate any output
frequency in the 7.29MHz to 833.33MHz range and most output
frequencies in the 925MHz to 1200MHz range (see Table 3A 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.
The IDT8T49N222I has three operating modes to support a very
broad spectrum of applications:
1) Frequency Synthesizer
• 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.
2) High-Bandwidth Frequency Translator
• Applications: PCI Express, Computing, General Purpose
• Translates any input clock in the 16MHz - 710MHz frequency
range into any supported output frequency.
• 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.
3) Low-Bandwidth Frequency Translator
• Applications: Networking & Communications.
• Translates any input clock in the 8kHz –710MHz frequency
range into any supported output frequency.
• This mode supports PLL loop bandwidths in the 10Hz - 580Hz
range and makes use of an external crystal to provide
significant jitter attenuation.
This device provides a factory-programmed default power-up
configuration burned into One-Time Programmable (OTP) memory.
The configuration is specified by the customer and is programmed by
IDT during the final test phase from an on-hand stock of blank
devices.
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 written every time the device powers-up.
Features
• Fourth generation FemtoClock® NG technology
• Universal Frequency Translator
• Zero ppm frequency translation
• Two outputs, individually programmable as LVPECL or LVDS
• Outputs may be individually set to use 2.5V or 3.3V output
levels
• Individually programmable output frequencies: 7.29MHz up to
1200MHz
• Two differential inputs support the following input types:
LVPECL, LVDS, LVHSTL, HCSL
• Input frequency range: 8kHz to 710MHz
• Hitless switching between inputs
• Crystal input frequency range: 16MHz to 40MHz
• Holdover support in the event both inputs fail
• One factory-set register configuration for power-up default state
• 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 156.25MHz, using a 40MHz crystal
(12kHz - 20MHz): 507fs (typical), Low Bandwidth Mode (FracN)
• Supports ITU-T G.8262 Synchronous Ethernet equipment slave
clocks (EEC option 1 and 2)
• Output supply voltage modes:
V_CC/V_CCA/V_CCOx
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
• Available in lead-free (RoHS 6) package
Pin Assignment
CLK_ACTIVE
VEE
LF0
LF1
VEE
VEE
nc
VCCA
HOLDOVER
CLK0BAD
CLK1BAD
XTALBAD
36 35 34 33 32 31 30 29 28 27 26 25
37
24
38
23
39
IDT8T49N222I
22
40
48 Lead VFQFN
21
41 _{7.0mm x 7.0mm x 0.925mm,} 20
42
package body
19
43
NL Package
18
44
45
Top View
17
16
46
15
47
14
48
13
1 2 3 4 5 6 7 8 9 10 11 12
VEE
nc
VCC
S_AO
S_A1
Reserved
nc
SCLK
SDATA
VCC
PLL_BYPASS
nc
IDT8T49N222BNLGI REVISION A MAY 13, 2013
1
©2013 Integrated Device Technology, Inc.