19-3486; Rev 1; 11/05
10Gbps Clock and Data Recovery
with Limiting Amplifier
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 trans-
ceiver modules. The chipset is XFI compliant and offers
multirate operation for data rates from 9.95Gbps to
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 amplifi-
er. The phase-locked loop (PLL) is optimized for jitter tol-
erance 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
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 refer-
ence 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.
♦ Multirate Operation from 9.95Gbps to 11.1Gbps
♦ 7mVP-P Input Sensitivity (BER ≤ 10-12)
♦ 0.6UIP-P Total High-Frequency Jitter Tolerance
♦ Low-Output Jitter Generation: 7mUIRMS
♦ Low-Output Deterministic Jitter: 4.6psP-P
♦ XFI-Compliant Output Interface
♦ LOS Indicator with Programmable Threshold
♦ LOL Indicator
♦ Power Dissipation: 350mW
TEMP RANGE PIN-
0°C to +85°C 24 QFN
MAX3991UTG+* 0°C to +85°C 24 QFN
*Future product—contact factory for availability.
+Denotes lead-free package.
9.95Gbps to 11.1Gbps Optical XFP Modules
SONET OC-192/SDH STM-64 XFP Transceivers
10.3Gbps/11.1Gbps Ethernet XFP Transceivers
10.5Gbps Fibre-Channel XFP Transceivers
10Gbps DWDM Transceivers
Typical Application Circuit appears at end of data sheet.
24 23 22 21 20 19
7 8 9 10 11 12
4mm x 4mm QFN*
*THE EXPOSED PAD MUST BE CONNECTED TO CIRCUIT-BOARD GROUND FOR
PROPER THERMAL AND ELECTRICAL PERFORMANCE.
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.