General Description

The 845254 is a 3.3V/2.5V CML clock generator designed for

Ethernet applications. The device synthesizes either a 50MHz,

62.5MHz, 100MHz, 125MHz, 156.25MHz, 250MHz or 312.5MHz

clock signal with excellent phase jitter performance. The clock signal

is distributed to four low-skew differential CML outputs. The device is

suitable for driving the reference clocks of Ethernet PHYs. The

device supports 3.3V and 2.5V voltage supply and is packaged in a

small, lead-free (RoHS 6) 32-lead VFQFN package. The extended

temperature range supports telecommunication, wireless

infrastructure and networking end equipment requirements.

特性 Features

? Clock generation of: 50MHz, 62.5MHz, 100MHz, 125MHz,

156.25MHz, 250MHz and 312.5MHz

? Four differential CML clock output pairs

? 25MHz reference clock (selectable internal crystal oscillator and

external LVCMOS clock)

? RMS phase jitter @ 125MHz, using a 25MHz crystal

(1.875MHz – 20MHz): 0.405ps (typical)

Offset Noise Power

100Hz.................... -104.6 dBc/Hz

1kHz.................... -118.4 dBc/Hz

10kHz................... -124.1 dBc/Hz

100kHz................... -125.3 dBc/Hz

? LVCMOS interface levels for the control inputs

? Full 3.3V and 2.5V supply voltage

? Available in lead-free (RoHS 6) 32 VFQFN package

? -40°C to 85°C ambient operating temperature

? Replacement part: 843002AYLF