8T49N4811 Datasheet, PDF (1/34 Pages) Integrated Device Technology – Fourth generation FemtoClock

I²C Programmable Ethernet Clock
Generator
8T49N4811
DATA SHEET
General Description
The 8T49N4811I is a highly flexible FemtoClock^® NG
pin-programmable clock generator suitable for networking and
communications applications. It is able to generate five different
output frequencies with multiple copies of each. A fundamental mode
crystal, single-ended, or differential input reference may be used as
the source for the output frequency.
The use of pin-programming to select the input source / frequency,
desired output frequencies and output styles allow a single device to
be used in a wide variety of applications without the need for register
programming.
Selection pins use 3-level options to maximize flexibility while
minimizing package size. Selection is performed by tying a selection
pin high or low or by leaving it floating, eliminating the need for
passive components to drive a desired logic level.
Features
• Fourth generation FemtoClock^® NG technology
• Generates multiple copies of 25MHz, 50MHz, 100MHz, 125MHz,
156.25MHz or 312.5MHz
• Typical input frequency is 25MHz, with optional 125MHz and
156.25MHz input support
• Differential outputs are pin programmable for LVDS or LVPECL
• RMS phase jitter at 156.25MHz: <300fs typical
• Power Supply Rejection Ratio better than -50dBc from
10k-1.5MHz at 3.3V power supply
• Full 3.3V and 2.5V Supply Voltages
• -40°C to +85°C ambient operating temperature
• 56-pin VFQFPN, lead-free (RoHS 6) packaging
Block Diagram
2.5V ±5% or 3.3V ±10%
PLL Bypass
SDATA, SCLK
IIC_ADRX_SEL
IN_SEL
XTAL_IN
f_IN
XTAL_OUT
DIN
nDIN
SLEW_LVCMOS
LVCMOS_CTRL
Qx_CTRL
QB_CTRL [1:0]
INPUT_DIVSEL
DIVSEL_x
100Ω
3
4
/A
0
1
OSC ₀
1
f_IN
APLL
/B
0
1
/C
0
1
/D0
Frequency,
Output Type,
Slew Rate, &
Output Enable
Control
Input Divider
/D1
Frequency Select
Output Enable,Type, & Slew Rate Control
Bank A 1 LVPECL/LVDS
125MHz/156.25MHz/312.5MHz
Bank B 6 LVPECL/LVDS
50MHz/125MHz/156.25MHz
Bank C 2 LVPECL/LVDS
100MHz/125MHz/156.25MHz
Bank D0 1 LVPECL/LVDS
25MHz/125MHz/156.25MHz
Bank D1 1 LVCMOS
25MHz/125MHz
8T49N4811 REVISION A 3/30/15
1
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