The MAX3991 is a 10Gbps clock and data recovery
(CDR) with limiting amplifier IC for XFP optical receivers.
The MAX3991 and the MAX3992 (CDR with equalizer)
form a signal conditioner chipset for use in XFP transceiver
modules. The chipset is XFI compliant and offers
multirate operation for data rates from 9.95Gbps to
11.1Gbps.
The MAX3991 has 7mVP-P input sensitivity (BER < 10-12),
which allows direct connection to a transimpedance
amplifier without the use of a stand-alone limiting amplifier.
The phase-locked loop (PLL) is optimized for jitter tolerance
and provides 0.6UI of high-frequency tolerance
in SONET, Ethernet, and Fibre-Channel applications. The
MAX3991 output provides 27% margin to the XFP eye
mask specification.
An AC-based power detector toggles the loss-of-signal
(LOS) output when the input signal swing is below the
user-programmed assert threshold. An external reference
clock, with frequency equal to 1/64 or 1/16 of the
serial data rate is used to aid in frequency acquisition. A
loss-of-lock (LOL) indicator is provided to indicate the
lock status of the receiver PLL.
The MAX3991 is available in a 4mm x 4mm, 24-pin QFN
package. It consumes 350mW from a single +3.3V supply
and operates over the 0°C to +85°C temperature range.