GENERAL DESCRIPTION

The AD9577 provides a multioutput clock generator function, along with two on-chip phase-locked loop cores, PLL1 and PLL2, optimized for network clocking applications. The PLL designs are based on the Analog Devices, Inc., proven portfolio of high performance, low jitter frequency synthesizers to maximize network performance. The PLLs have I2C programmable output frequencies and formats. The fractional-N PLL can support spread spectrum clocking for reduced EMI radiated peak power. Both PLLs can support frequency margining. Other applications with demanding phase noise and jitter requirements can benefit from this part.

FEATURES

Fully integrated dual PLL/VCO cores

1 integer-N and 1 fractional-N PLL

Continuous frequency coverage from 11.2 MHz to 200 MHz

Most frequencies from 200 MHz to 637.5 MHz available

PLL1 phase jitter (12 kHz to 20 MHz): 460 fs rms typical

PLL2 phase jitter (12 kHz to 20 MHz)

Integer-N mode: 470 fs rms typical

Fractional-N mode: 660 fs rms typical

Input crystal or reference clock frequency

Optional reference frequency divide-by-2

I2C programmable output frequencies

Up to 4 LVDS/LVPECL or up to 8 LVCMOS output clocks

1 CMOS buffered reference clock output

Spread spectrum: downspread [0, −0.5]

2 pin-controlled frequency maps: margining

Integrated loop filters

Space saving, 6 mm × 6 mm, 40-lead LFCSP package

1.02 W power dissipation (LVDS operation)

1.235 W power dissipation (LVPECL operation)

3.3 V operation

APPLICATIONS

Low jitter, low phase noise multioutput clock generator for

data communications applications including Ethernet,

Fibre Channel, SONET, SDH, PCI-e, SATA, PTN, OTN,

ADC/DAC, and digital video

Spread spectrum clocking