GENERAL DESCRIPTION

The 873991-147 is a low voltage, low skew, 3.3V LVPECL or ECL

Clock Generator and a member of the family of High Performance

Clock Solutions from IDT. The 873991-147 has two selectable clock

inputs. The CLK, nCLK pair can accept LVPECL, LVDS, LVHSTL,

SSTL and HCSL input levels and, the REF_CLK pin can accept a

LVCMOS or LVTTL input levels. This device has a fully integrated

PLL along with frequency confi gurable outputs. An external feedback

input and output regenerates clocks with “zero delay”.

The four independent banks of outputs each have their own output

dividers, which allow the device to generate a multitude of different bank frequency ratios and output-to-input frequency ratios.

The output frequency range is 25MHz to 480MHz and the input

frequency range is 6.25MHz to 120MHz. The PLL_EN input can

be used to bypass the PLL for test and system debug purposes.

In bypass mode, the input clock is routed around the PLL and into

the internal output dividers.

The 873991-147 also has a SYNC output which can be used for

system synchronization purposes. It monitors Bank A and Bank

C outputs for coincident rising edges and signals a pulse per the

timing diagrams in this data sheet. This feature is used primarily

in applications where Bank A and Bank C are running at different

frequencies, and is particularly useful when they are running at

non-integer multiples of each other.

Example Applications:

1. Line Card Multiplier: Multiply 19.44MHz from a back-plane

to 77.76MHz on the line card ASIC and Serdes.

2. Zero Delay Buffer: Fan out up to thirteen 100MHz copies

from a reference clock to multiple processing units on an

embedded system.

FEATURES

• Fourteen differential 3.3V LVPECL/ECL outputs

• Selectable differential or REF_CLK inputs

• CLK, nCLK can accept the following input levels:

LVPECL, LVDS, LVHSTL, SSTL, HCSL

• REF_CLK accepts the following input levels: LVCMOS, LVTTL

• Input clock frequency range: 6.25MHz to 120MHz

• Maximum output frequency: 480MHz

• VCO range: 200MHz to 960MHz

• Output skew: 250ps (maximum), outputs at the same frequency

• Cycle-to-cycle jitter: 55ps (maximum)

• LVPECL mode operating voltage supply range:

VCC = 3.135V to 3.465V, VEE = 0V

• ECL mode operating voltage supply range:

VCC = 0V, VEE = -3.465V to -3.135V

• 0°C to 50°C ambient operating temperature

• Available in lead-free (RoHS 6) package

• Use replacement part 873996AYLF