ADN2890 Datasheet, PDF (1/12 Pages) Analog Devices – 3.3 V 2.7 Gb/s Limiting Amplifier

FEATURES
SFP reference design available
Input sensitivity: 3 mV p-p
80 ps rise/fall times
CML outputs: 700 mV p-p differential
Programmable LOS detector: 2 mV to 13 mV
Rx signal strength indicator (RSSI):
SFF-8472 compliant average power measurement
Single-supply operation: 3.3 V
Low power dissipation: 130 mW
Available in space-saving 3 mm × 3 mm 16-lead LFCSP
APPLICATIONS
SFP/SFF/GBIC optical transceivers
OC-3/12/48, GbE, Fibre Channel receivers
10GBASE-LX4 transceivers
WDM transponders
3.3 V 2.7 Gb/s
Limiting Amplifier
ADN2890
GENERAL DESCRIPTION
The ADN2890 is a high gain, limiting amplifier optimized for
use in SONET, Gigabit Ethernet (GbE), and Fibre Channel
optical receivers that accept input levels of up to 2.0 V p-p
differential and have 3 mV p-p differential input sensitivity. The
ADN2890 provides the receiver functions of quantization and
loss of signal (LOS) detection. The ADN2890 can easily operate
at up to 3.2 Gb/s to support LX4 transceivers.
The limiting amplifier also measures average received power
based on a direct measurement of the photodiode current with
better than 1 dB of accuracy over the entire input range of the
receiver. This eliminates the need for external average Rx power
detection circuitry in SFF-8472 compliant optical transceivers.
The ADN2890 limiting amplifier operates from a single 3.3 V
supply, has low power dissipation, and is available in a space-
saving 3 mm × 3 mm 16-lead lead frame chip scale package
(LFCSP).
C_F R_F
FUNCTIONAL BLOCK DIAGRAM
AVCC AVEE
DRVCC DRVEE
ADN2890
PIN
ADN2880
NIN
DRVCC
50Ω
50Ω
OUTP
OUTN
50Ω
PD_VCC
PD_CATHODE
50Ω
3kΩ
V_REF
RSSI/LOS
DETECTOR
+V
10kΩ
LOS
RSSI_OUT ADuC7020
CAZ1
CAZ2
0.01µF
THRADJ SQUELCH
Figure 1.
Rev. 0
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