IDT8T49N524I Datasheet, PDF (1/37 Pages) Integrated Device Technology – Fourth Generation FemtoClock

Programmable FemtoClock^® NG LVPECL/LVDS
Dual 4-Output Fractional Clock Generator
IDT8T49N524I
DATA SHEET
General Description
The IDT8T49N524I is an eight output programmable any-rate dual
clock generator with selectable LVDS or LVPECL outputs. Both clock
generators use Fractional Output Dividers to be able to generate out-
put frequencies that are independent of each other and independent
of the input frequency. Output frequencies for both clock generators
are generated from a single crystal or reference clock.
Clock Generator A supports three different factory-programmed
default frequencies that can be selected from using only the FSEL
control pins. Alternatively any desired output frequency can be
programmed over the I²C serial port. The chosen output frequency is
then driven out the QA0 to QA3 outputs.
Clock Generator B supports a single factory-programmed default
frequency. It can also be programmed for any output frequency via
the serial port. The output frequency is driven out the QB0 to QB3
outputs.
Some examples of frequency configurations that can be achieved
are shown in Table 5A. Please consult IDT for programming software
that can be used to determine the required settings for any desired
configuration.
Excellent phase noise performance is achieved with IDT’s fourth
Generation FemtoClock^® NG PLL technology, which delivers
sub-0.5ps RMS phase jitter in the integer divide mode.
Features
• Fourth Generation FemtoClock^® NG PLL technology
• Eight outputs selectable as LVPECL or LVDS
• Input selectable: fundamental mode crystal or clock reference
• Supports fundamental mode crystals from 10MHz - 40MHz
• CLK, nCLK input pair can accept the following differential input
levels: LVPECL, LVDS, HCSL
• Input frequencies from 5MHz up to 800MHz
• Two independent output frequencies can be generated
• Output frequencies independent of each other and of input
• Output frequencies from 15.234MHz - 645MHz, and
975MHz - 1290MHz, (See Table 5D for details)
• RMS phase jitter at 125MHz (12kHz - 20MHz): 0.282ps (typical)
• RMS phase jitter at 156.25MHz (12kHz - 20MHz):
0.278ps (typical)
• Full 2.5V or 3.3V power supply
• I²C programming interface
• -40°C to 85°C ambient operating temperature
• Lead-free (RoHS 6) packaging
• V_CC / V_CCA / V_CCO
3.3V / 3.3V / 3.3V
3.3V / 3.3V / 2.5V (LVPECL only)
2.5V / 2.5V / 2.5V
Pin Assignment
VEE_B
SCLK
SDATA
VEE
V_CCA
LOCK
V_EE
V_CC
CLK_SEL
VEE_A
30 29 28 27 26 25 24 23 22 21
31
20
32
19
33
IDT8T49N524I
18
34 40 Lead VFQFN 17
35 6mm x 6mm x 0.925mm 16
36 ^{4.65mm x 4.65mm EPad} 15
37
NL Package
14
38
Top View
13
39
12
40
11
1 2 3 4 5 6 7 8 9 10
FSEL1
V_CC
V_EE
ADDR_SEL
FSEL0
nCLK
CLK
VEE
XTAL_OUT
XTAL_IN
IDT8T49N524NLGI REVISION A JANUARY 23, 2014
1
©2014 Integrated Device Technology, Inc.