January 1997
ML4622, ML4624
Fiber Optic Data Quantizer
GENERAL DESCRIPTION
FEATURES
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
capable of accepting an input signal as low as 2mVP-P
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.
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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.
Data rates up to 40MHz or 80MBd
Can be powered by either +5V providing TTL or raised
ECL level outputs or –5.2V providing ECL levels
s Low noise design: 25µV RMS over bandwidth
s Adjustable Link Monitor function with hystersis
s Wide 55dB input dynamic range
s Low power design
s ML4624 is pin compatible with the ML4621
APPLICATIONS
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IEEE 802.3 10BASE-FL Receiver
IEEE 802.5 fiber optic token ring, 4 and 16mbps
Fiber Optic Data Communications and
Telecommunications Receivers
ML4622/ML4624 BLOCK DIAGRAM
CF1
CF2
ECL+
ECL–
BIAS
VIN+
ECL
CMP
AMP
VIN–
TTL
CMP
TTL OUT
CMP ENABLE
∫
VCC TTL*
VDC
VCC
GND
VREF
VTHADJ
GND TTL
REF
THRESH
GEN
LINK DETECT
TTL LINK MON
CTIMER
*ML4624 ONLY
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