MAX3760ESA ,622Mbps / Low-Noise Transimpedance Preamplifier for LAN and WAN Optical ReceiversApplicationsTypical Application Circuit622Mbps ATM LAN Optical Receivers+5V622Mbps WAN Optical Rece ..
MAX3761EEP ,Low-Power / 622Mbps Limiting Amplifiers with Chatter-Free Power Detect for LANsApplications tested and guaranteed only at T = +25°C.A622Mbps LAN/ATM LAN Receivers155Mbps LAN/ATM ..
MAX3761EEP ,Low-Power / 622Mbps Limiting Amplifiers with Chatter-Free Power Detect for LANsapplications. Interface Logic—MAX3766An integrated power detector senses the input signal’samplitud ..
MAX3761EEP ,Low-Power / 622Mbps Limiting Amplifiers with Chatter-Free Power Detect for LANsELECTRICAL CHARACTERISTICS(V = +4.5V to +5.5V, DISABLE = low, T = -40°C to +85°C, unless otherwise ..
MAX3761EEP+ ,Low-Power, 622Mbps Limiting Amplifiers with Chatter-Free Power Detect for LANsApplicationstested and guaranteed only at T = +25°C.A+Denotes a lead-free/RoHS-compliant package.62 ..
MAX3762EEP ,Low-Power / 622Mbps Limiting Amplifiers with Chatter-Free Power Detect for LANsFeaturesThe MAX3761/MAX3762 limiting amplifiers, with 4mV' Chatter-Free Power Detector with Program ..
MAX734CPA ,+12V, 120mA Flash Memory Programming Supply
MAX734CPA ,+12V, 120mA Flash Memory Programming Supply
MAX734CPA ,+12V, 120mA Flash Memory Programming Supply
MAX734CPA+ ,12V, 120mA Flash Memory Programming Supply
MAX734CSA ,+12V, 120mA Flash Memory Programming Supply
MAX734CSA ,+12V, 120mA Flash Memory Programming Supply
MAX3760ESA
622Mbps / Low-Noise Transimpedance Preamplifier for LAN and WAN Optical Receivers
General DescriptionThe MAX3760 is a transimpedance preamplifier for
622Mbps ATM applications. It operates from a single
+5V supply and typically consumes only 100mW
power. The preamplifier converts a small photodiode
current to a differential voltage. A DC cancellation cir-
cuit provides a true differential output swing over a
wide range of input current levels, thus reducing pulse-
width distortion.
6.5kΩtransimpedance gain and 560MHz bandwidth,
combined with low 73nA input-referred noise, provide
-31.5dBm typical sensitivity in 1300nm receivers. The
circuit accepts a 1mAp-p input current, resulting in a
typical optical overload of -3dBm. The device operates
over an extended temperature range of -40°C to +85°C.
The MAX3760 is internally compensated and requires
few external components. In die form it includes a
space-saving filter connection, which provides positive
bias for the photodiode through a 1kΩresistor to VCC.
These features, combined with the die aspect ratio and
dimensioning, allow the MAX3760 to assemble easily
into a TO-style header with a photodiode.
The MAX3760 is designed to be used with either the
MAX3761 or the MAX3762 limiting-amplifier ICs. When
combined with a photodiode, the chipset forms a com-
plete 5V, 622Mbps receiver. The MAX3760 is available
in die form and in an 8-pin SO package.
________________________Applications622Mbps ATM LAN Optical Receivers
622Mbps WAN Optical Receivers
____________________________Features73nA RMS Input-Referred Noise560MHz Bandwidth1mA Peak Input Current6.5kΩGainOperation from -40°C to +85°C100mW Typical Power ConsumptionSingle +5V Supply
MAX3760ransimpedance
Preamplifier for LAN and WAN Optical Receivers
Typical Application Circuit
Pin Configuration
MAX3760
622Mbps, Low-Noise Transimpedance
Preamplifier for LAN and WAN Optical Receivers
ABSOLUTE MAXIMUM RATINGS
DC ELECTRICAL CHARACTERISTICS(VCC= +4.5V to +5.5V, COMP = GND, 100Ωload between OUT+ and OUT-, TA= -40°C to +85°C, unless otherwise noted. Typical
values are at VCC= +5.0V, TA= +25°C.) (Note 1)
AC ELECTRICAL CHARACTERISTICS(VCC= +4.5V to +5.5V, COMP = open, CIN= 0.75pF, outputs terminated differentially into 100Ω, 8-pin SO package in MAX3760
EV kit, TA= +25°C, unless otherwise noted. Typical values are at VCC= +5V.) (Notes 2, 3)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
Note 1:Dice are tested at TA= +25°C.
Note 2:AC characteristics are guaranteed by design and characterization.
Note 3:CIN is the source capacitance presented to the die. Includes package parasitic, photo diode, and parasitic interconnect
capacitance.
Note 4:Input is a 622Mbps 1-0 pattern, signal amplitude = 0 to 1mA, extinction ratio (re) = 10.
Note 5:Measured with a 4-pole, 470MHz Bessel filter.
VCC........................................................................-0.5V to +7.0V
Continuous Current
IN, FILTER..........................................................-5mA to +5mA
OUT+, OUT-...................................................-25mA to +25mA
Voltage at INREF...................................................-0.5V to +0.5V
Voltage at COMP........................................-0.5V to (VCC+ 0.5V)
Continuous Power Dissipation (TA= +85°C)
SO (derate 5.88mW/°C above +85°C)..........................383mW
Storage Temperature Range.............................-65°C to +160°C
Lead Temperature (soldering, 10sec).............................+300°C
Operating Junction Temperature Range (die).....-55°C to +150°C
Processing Temperature (die).........................................+400°C
MAX3760
622Mbps, Low-Noise Transimpedance
Preamplifier for LAN and WAN Optical Receivers
__________________________________________Typical Operating Characteristics(MAX3760 EV kit, VCC= +5.0V, COMP = open, TA= +25°C, unless otherwise noted.)
Pin Description
MAX3760
622Mbps, Low-Noise Transimpedance
Preamplifier for LAN and WAN Optical Receiversypical Operating Characteristics (continued)(MAX3760 EV kit, VCC= +5.0V, COMP = open, TA= +25°C, unless otherwise noted.)
Detailed DescriptionThe MAX3760 is a transimpedance amplifier designed
for 622Mbps fiber optic applications. As shown in the
Functional Diagram (Figure 1), it comprises a transim-
pedance amplifier, a paraphase amplifier with emitter-
follower outputs, and a DC cancellation circuit.
Transimpedance AmplifierThe signal current at the input flows into a high-gain
amplifier’s summing node. Shunt feedback through RF
converts this current to a voltage with 6.5kΩgain.
Diode D1 clamps the output voltage for large input cur-
rents. INREF is a direct connection to the input transis-
tor’s emitter, and must be connected directly to the
photodetector AC ground return for best performance.
Paraphase AmplifierThe paraphase amplifier converts single-ended signals to
differential signals and introduces a voltage gain of 2.
This signal drives a pair of internally biased emitter follow-
ers, Q2 and Q3, which form the output stage. Resistors
R1 and R2 provide back-termination at the output, deliv-
ering a 100Ωdifferential output impedance. The output
emitter followers are designed to drive a 100Ωdifferential
load between OUT+ and OUT-. The MAX3760 can also
be terminated with higher output impedances for
increased gain and output voltage swing. The MAX3760
will not drive a 50Ωload to ground.For best noise rejec-
tion, terminate the MAX3760 with differential loads.
DC Cancellation CircuitThe DC cancellation circuit removes the input signal’s
DC component by employing low-frequency feedback.
This feature centers the input signal within the transim-
pedance amplifier’s dynamic range, thereby reducing
pulse-width distortion on large input signals.
The paraphase amplifier’s output is sensed through
resistors R3 and R4, then filtered, amplified, and fed
back to the base of transistor Q4. The transistor draws
the input signal’s DC component away from the trans-
impedance amplifier’s summing node.
The MAX3760 DC cancellation loop is internally com-
pensated and does not require external capacitors in
most 622Mbps applications. Add external capacitance
at the COMP pin to reduce the DC cancellation circuit’s
frequency response and improve data-dependent jitter.
Connecting the COMP pin directly to GND disables the
circuit. The DC cancellation circuit can sink up to 1mA
at the input.
MAX3760
622Mbps, Low-Noise Transimpedance
Preamplifier for LAN and WAN Optical ReceiversFigure 1. Functional Diagram
MAX3760The MAX3760 minimizes pulse-width distortion for data
sequences exhibiting a 50% duty cycle. A duty cycle
significantly different from 50% will cause the MAX3760
to generate pulse-width distortion.
DC cancellation current is drawn from the input and
creates noise. This is not a problem for low-level signals
with little or no DC component. Preamplifier noise
increases for signals with significant DC component
(see Typical Operating Characteristics).
The MAX3760 operates with the photodetector cathode
connected to VCC, as shown in the Typical Application
Circuit. Connecting the photodetector anode to GND
and the cathode to IN defeats the DC cancellation cir-
cuit and causes pulse-width distortion.
Input ReferenceINREF is the reference point for IN. Connect it as close
as possible to the photodetector diode’s AC ground. The
photodetector’s AC ground is usually the ground of the
photodetector’s filter capacitor. The total length from
INREF, through the filter capacitor and the diode, and
back to the input should be no more than 2cm.
Applications Information
Optical Power DefinitionsMany of the MAX3760’s specifications relate to the
input signal amplitude. When working with fiber optic
receivers, the optical input is usually expressed in
terms of average optical power and extinction ratio.
Use the relations given in Table 1 to convert optical
power to input signal when designing with the
MAX3760.
Calculating Sensitivity,
Overload, and Linear Range
Sensitivity CalculationThe MAX3760’s input-referred RMS noise current (in)
generally dominates the receiver sensitivity. In a system
where the bit error rate (BER) is 1E - 10, the signal-to-
noise ratio must always exceed 12.7. The sensitivity,
expressed in average power, can be estimated as:
Where ris the photodiode responsivity in A/W.
Input OverloadThe overload is the largest input that the MAX3760
accepts while meeting specifications. It is calculated
as:
Linear RangeThe MAX3760 has high gain, which limits the output
when the input signal exceeds 20µAp-p. It operates
with 90% linearity for inputs not exceeding the follow-
ing:
622Mbps, Low-Noise Transimpedance
Preamplifier for LAN and WAN Optical Receivers
