MAX3267CSA ,1.25Gbps/2.5Gbps / 3V to 5.5V / Low-Noise Transimpedance Preamplifiers for LANsApplicationsN.C. 2 7 OUT+Gigabit EthernetMAX3266MAX3267IN 3 6 OUT-1.0Gbps to 2.5Gbps Optical Receiv ..
MAX3268CUB ,3.0V to 5.5V / 1.25Gbps/2.5Gbps Limiting Amplifiersfeatures include 150ps max Edge Speed (MAX3265)RMS power detectors with programmable loss-of-signa ..
MAX3268CUB+T ,+3.0V to +5.5V, 1.25Gbps/2.5Gbps Limiting AmplifiersMAX3264/MAX3265/MAX3268/MAX3269/MAX3765/MAX376819-1523; Rev 7, 2/06+3.0V to +5.5V, 1.25Gbps/2.5Gbps ..
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MAX3269C ,+3.0 V to +5.5 V, 1.25 Gbp/2.5Gbp limiting amplifierELECTRICAL CHARACTERISTICS(Data outputs terminated per Figure 1, V = +3.0V to +5.5V, T = 0°C to +70 ..
MAX3269CUB ,3.0V to 5.5V / 1.25Gbps/2.5Gbps Limiting AmplifiersApplicationsMAX3265C/D 0°C to +70°C Dice*Gigabit Ethernet Optical Receivers †MAX3265EUE -40°C to +8 ..
MAX692A ,Microprocessor Supervisory CircuitsElectrical Characteristics(V = 4.75V to 5.5V for MAX690A/MAX802L/MAX805L, V = 4.5V to 5.5V for MAX6 ..
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MAX692ACPA ,Microprocessor Supervisory CircuitsApplicationsOrdering Information continued on last page.* Dice are specified at T = +25°CBattery-Po ..
MAX692ACPA ,Microprocessor Supervisory CircuitsELECTRICAL CHARACTERISTICS(V = 4.75V to 5.5V for MAX690A/MAX802L/MAX805L, V = 4.5V to 5.5V for MAX6 ..
MAX692ACSA ,Microprocessor Supervisory CircuitsFeaturesThe MAX690A/MAX692A/MAX802L/MAX802M/MAX805L ' Precision Supply-Voltage Monitor:reduce the c ..
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MAX3267CSA
1.25Gbps/2.5Gbps / 3V to 5.5V / Low-Noise Transimpedance Preamplifiers for LANs
General DescriptionThe MAX3266 is a transimpedance preamplifier for
1.25Gbps LAN fiber optic receivers. The circuit features
200nA input-referred noise, 920MHz bandwidth, and
1mA input overload.
The MAX3267 provides a pin-for-pin compatible solu-
tion for communications up to 2.5Gbps. It features
500nA input-referred noise, 1.9GHz bandwidth, and
1mA input overload.
Both devices operate from a single +3.0V to +5.5V sup-
ply and require no compensation capacitor. They also
include a space-saving filter connection that provides
positive bias for the photodiode through a 1.5kΩresistor
to VCC. These features allow easy assembly into a TO-46
or TO-56 header with a photodiode.
The 1.25Gbps MAX3266 has a typical optical dynamic
range of -24dBm to 0dBm in a shortwave (850nm)
configuration or -27dBm to -3dBm in a longwave
(1300nm) configuration. The 2.5Gbps MAX3267 has a
typical optical dynamic range of -21dBm to 0dBm in a
shortwave configuration or -24dBm to -3dBm in a long-
wave configuration.
ApplicationsGigabit Ethernet
1.0Gbps to 2.5Gbps Optical Receivers
Fibre Channel
Features200nA Input-Referred Noise (MAX3266)
500nA Input-Referred Noise (MAX3267)920MHz Bandwidth (MAX3266)
1900MHz Bandwidth (MAX3267)1mA Input OverloadSingle +3.0V to +5.5V Supply Voltage
MAX3266/MAX3267
1.25Gbps/2.5Gbps, 3V to 5.5V, Low-Noiseransimpedance Preamplifiers for LANs
Typical Application Circuit
Pin Configuration
Ordering Information
MAX3266/MAX3267
1.25Gbps/2.5Gbps, 3V to 5.5V, Low-Noise
Transimpedance Preamplifiers for LANs
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(VCC= +3.0V to +5.5V, TA= 0°C to +70°C, 100Ωload between OUT+ and OUT-. Typical values are at TA = +25°C, VCC = 3.3V,
source capacitance = 0.85pF, unless otherwise noted.) (Note 1)
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.
Supply Voltage (VCC - GND).................................-0.5V to +6.0V
IN Current..............................................................-4mA to +4mA
FILTER Current......................................................-8mA to +8mA
Voltage at OUT+, OUT-...................(VCC - 1.5V) to (VCC + 0.5V)
Continuous Power Dissipation (TA= +70°C)
SO package (derate 6.7mW/°C above +70°C).............533mW
Storage Temperature Range.............................-55°C to +150°C
Operating Junction Temperature (die)..............-55°C to +150°C
Processing Temperature (die).........................................+400°C
Lead Temperature (soldering, 10sec).............................+300°C
Note 1:Source Capacitance represents the total capacitance at the IN pin during characterization of noise and bandwidth parame-
ters. Figure 1 shows the typical source capacitance vs. reverse voltage for the photodiode used during characterization of
TO-56 header packages. Noise and bandwidth will be affected by the source capacitance. See the Typical Operating
Characteristicsfor more information.
Note 2:Input-Referred Noise is calculated as RMS Output Noise / (Gain at f = 10MHz). Noise Density is (Input-Referred Noise) /
√bandwidth. No external filters are used for the noise measurements.
Note 3:Deterministic Jitter is measured with the K28.5 pattern applied to the input [00111110101100000101].
MAX3266/MAX3267
1.25Gbps/2.5Gbps, 3V to 5.5V, Low-Noise
Transimpedance Preamplifiers for LANs
Typical Operating Characteristics(VCC= +3.3V, TA= +25°C, MAX3266/MAX3267 EV kit, source capacitance = 0.85pF, unless otherwise noted.)
Pin Description
MAX3266/MAX3267
1.25Gbps/2.5Gbps, 3V to 5.5V, Low-Noise
Transimpedance Preamplifiers for LANs
Typical Operating Characteristics (continued)(VCC= +3.3V, TA= +25°C, MAX3266/MAX3267 EV kit, source capacitance = 0.85pF, unless otherwise noted.)
MAX3266/MAX3267
1.25Gbps/2.5Gbps, 3V to 5.5V, Low-Noise
Transimpedance Preamplifiers for LANs
General DescriptionThe MAX3266 is a transimpedance amplifier designed
for 1.25Gbps fiber optic applications. Figure 2 is a func-
tional diagram of the MAX3266, which comprises a trans-
impedance amplifier, a voltage amplifier, an output
buffer, an output filter, and a DC cancellation circuit.
The MAX3267, a transimpedance amplifier designed
for 2.5Gbps fiber optic applications, shares similar
architecture with the MAX3266.
Transimpedance AmplifierThe signal current at the input flows into the summing
node of a high-gain amplifier. Shunt feedback throughconverts this current to a voltage with gain of approx-
imately 2.2kΩ(1.0kΩfor MAX3267). Schottky diodes
clamp the output voltage for large input currents, as
shown in Figure 3.
Voltage AmplifierThe voltage amplifier converts single-ended signals to
differential signals and introduces a voltage gain.
Output BufferThe output buffer provides a reverse-terminated volt-
age output. The buffer is designed to drive a 100Ωdif-
ferential load between OUT+ and OUT-. The output
current is divided between internal, 50Ωload resistors
and the external load resistor. In the typical operating
circuit, this creates a voltage divider with gain of 1/2.
The MAX3266 can also be terminated with higher out-
put impedances, which increases gain and output volt-
age swing.
For optimum supply-noise rejection, the MAX3266
should be terminated with a differential load. If a single-
ended output is required, the unused output should be
similarly terminated. The MAX3266 will not drive a DC-
coupled, 50Ωgrounded load.
MAX3266/MAX3267
1.25Gbps/2.5Gbps, 3V to 5.5V, Low-Noise
Transimpedance Preamplifiers for LANs
Output FilterThe MAX3266 includes a 1-pole lowpass filter which
limits the circuit bandwidth and improves noise perform-
ance.
DC Cancellation CircuitThe DC cancellation circuit uses low-frequency feed-
back to remove the DC component of the input signal
(Figure 4). This feature centers the input signal within
the transimpedance amplifier’s linear range, thereby
reducing pulse-width distortion on large input signals.
The DC cancellation circuit is internally compensated
and therefore does not require external capacitors. This
circuit minimizes pulse-width distortion for data
sequences that exhibit a 50% duty cycle. A duty cycle
significantly different from 50% will cause the MAX3266
to generate pulse-width distortion.
DC cancellation current is drawn from the input and
creates noise. For low-level signals with little or no DC
component, this is not a problem. Amplifier noise will
increase for signals with significant DC component (see
Typical Operating Characteristics).
Applications Information
Optical Power RelationsMany of the MAX3266 specifications relate to the input
signal amplitude. When working with fiber optic
receivers, the input is usually expressed in terms of aver-
age optical power and extinction ratio. Figure 5 shows
relations that are helpful for converting optical power to
input signal when designing with the MAX3266.
Optical power relations are shown in Table 1; the defini-
tions are true if the average duty cycle of the input data
is 50%.
Optical Sensitivity CalculationThe input-referred RMS noise current (IN) of the
MAX3266 generally determines the receiver sensitivity.
To obtain a system bit error rate (BER) of 1E-12, the
signal-to-noise ratio must always exceed 14.1. The
input sensitivity, expressed in average power, can be
estimated as:
Where ris the photodiode responsivity in A/W.
Input Optical OverloadThe overload is the largest input that the MAX3266
accepts while meeting specifications. The optical over-
load can be estimated in terms of average power with
the following equation:
