January 1997

ML4622, ML4624

Fiber Optic Data Quantizer

GENERAL DESCRIPTION

The ML4622 and ML4624 data quantizers are low noise,

wideband, bipolar monolithic ICs designed specifically for

signal recovery applications in fiberoptic receiver systems.

They contain a wideband limiting amplifier which is

with a 55dB dynamic range. This high level of sensitivity

is achieved by using a DC restoration feedback loop

which nulls any offset voltage produced in the limiting

amplifier.

The output stage is a high speed comparator circuit with

both TTL and ECL outputs. An enable pin is included for

added control.

The Link Detect circuit provides a Link Monitor function

with a user selectable reference voltage. This circuit

monitors the peaks of the input signal and provides a

logic level output indicating when the input falls below

an acceptable level. This output can be used to disable

the quantizer and/or drive an LED, providing a visible link

status.

FEATURES

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Data rates up to 40MHz or 80MBd

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Can be powered by either +5V providing TTL or raised

ECL level outputs or –5.2V providing ECL levels

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Low noise design: 25

µV RMS over bandwidth

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Adjustable Link Monitor function with hystersis

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Wide 55dB input dynamic range

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Low power design

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ML4624 is pin compatible with the ML4621

APPLICATIONS

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IEEE 802.3 10BASE-FL Receiver

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IEEE 802.5 fiber optic token ring, 4 and 16mbps

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Fiber Optic Data Communications and

Telecommunications Receivers

ECL+

ECL–

TTL OUT

CMP ENABLE

GND

GND TTL

TTL LINK MON

CF1

CF2

THRESH

GEN

LINK DETECT

REF

*ML4624 ONLY

BIAS

ECL

CMP

TTL

CMP

AMP

∫

ML4622/ML4624 BLOCK DIAGRAM

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