Analog Devices Inc./Maxim Integrated MAX3272AEGP-TG05

Overview

MAX3272AEGP-TG05 from Maxim Integrated is a +3.3V, 2.5Gbps limiting amplifier IC designed for optical receiver front-ends. It delivers constant-level CML output with 90ps edge speed, 5ps deterministic jitter, and programmable loss-of-signal detection. Used in Fibre Channel and Gigabit Ethernet receivers, it interfaces directly with transimpedance amplifiers and drives laser driver or clock-data recovery circuits.

For engineers reviewing the MAX3272AEGP-TG05 datasheet, MAX3272AEGP-TG05 pinout, MAX3272AEGP-TG05 application, or MAX3272AEGP-TG05 equivalent, key selection criteria include input voltage range (15–1200mV_P-P), LOS hysteresis (3.3dB), squelch control timing (2.3–100µs), and CML output current programmability via LEVEL pin.

Technical Context

The MAX3272AEGP-TG05 implements a high-gain (42dB) SiGe bipolar limiting amplifier with integrated power detector and offset-correction loop. Its CML input buffer presents 100Ω differential impedance, while the CML output stage supports dual current levels (16mA/20mA) and polarity inversion via OUTPOL.

Loss-of-signal detection uses an averaging peak-power detector with resistor-programmable threshold (TH pin) and capacitor-programmable response time (CLOS pin). The MAX3272A variant includes ESD protection on both LOS pins-unlike the MAX3272-making it incompatible with +5V module interfacing but suitable for robust 3.3V systems.

Key Specifications

Pinout & Package

MAX3272AEGP-TG05 is housed in a 20-pin, 4mm × 4mm × 0.8mm thin QFN package (package code T2044-3) with exposed thermal pad connected to ground. Pin 20 is no-connect (N.C.).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar limiting amplifier applications.

Compared with MAX3272AEGP-TG05, MAX3272EGP offers identical limiting performance but lacks on-chip LOS ESD protection-requiring external components for robustness-while MAX3873 adds CDR functionality at the cost of higher power, different footprint, and non-interchangeable signal routing.

Availability

MAX3272AEGP-TG05 is available at Aetrix Electronics and suitable for Fibre Channel optical receivers, Gigabit Ethernet SFP modules, and SONET/SDH line cards requiring stable component supply across extended temperature ranges (−40°C to +85°C).

Supply support for MAX3272AEGP-TG05 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Maxim Integrated (now part of Analog Devices) designs precision analog, mixed-signal, and high-speed ICs for communications, computing, and industrial applications.

The MAX3272/MAX3272A product line targets low-power, compact optical receivers-specifically engineered to replace discrete limiting amplifier stages with integrated, jitter-optimized, and feature-rich alternatives for 2.5Gbps data links.

FAQ

What is the maximum input voltage range supported by the MAX3272AEGP-TG05?

The MAX3272AEGP-TG05 accepts differential input voltages from 15mV_P-P to 1200mV_P-P, covering the full dynamic range expected from transimpedance amplifiers in optical receivers. Absolute maximum ratings specify (V_CC − 2.4V) to (V_CC + 0.5V) per input pin, allowing safe operation up to +3.6V supply. This range ensures reliable detection of weak signals while avoiding saturation from overdriven inputs.

How does the LOS hysteresis function in the MAX3272AEGP-TG05, and what is its typical value?

The MAX3272AEGP-TG05 implements 3.3dB of built-in hysteresis between LOS assert and deassert thresholds to prevent chattering during marginal optical input conditions. This hysteresis is fixed by design and verified across temperature (−40°C to +85°C). For example, with R_TH = 20kΩ, the low-level assert threshold is 6.5mV_P-P and deassert occurs at 12.7mV_P-P, ensuring stable flagging even with slow optical power drift.

Can the MAX3272AEGP-TG05 be used with a +5V monitoring circuit connected to the LOS pins?

No-the MAX3272AEGP-TG05's LOS and LOS pins include on-chip ESD protection rated for 3.3V operation only. Connecting them directly to +5V logic violates the absolute maximum rating of −0.5V to (V_CC + 0.5V) = +3.8V max. In contrast, the MAX3272EGP variant lacks this protection and can interface with +5V systems-but requires external Schottky clamps like the MAX3202E for robustness. Always match LOS voltage domain to the MAX3272AEGP-TG05's 3.3V supply.

What is the purpose of the CAZ1 and CAZ2 pins on the MAX3272AEGP-TG05?

CAZ1 and CAZ2 form the external interface to the MAX3272AEGP-TG05's DC offset-correction loop. A capacitor (typically 0.1µF) placed between them sets the lower 3dB cutoff frequency (f_OC ≈ 2kHz) of the signal path, enabling rejection of low-frequency drift from transimpedance amplifiers or duty-cycle distortion. Leaving CAZ1/CAZ2 open disables the loop-recommended for 8B/10B protocols like Fibre Channel where low-frequency content is minimal.

Does the MAX3272AEGP-TG05 support both AC-coupled and DC-coupled inputs?

The MAX3272AEGP-TG05 requires AC-coupled inputs to ensure proper operation of its internal offset-correction loop. DC coupling blocks the feedback path needed to cancel input DC offsets, leading to output saturation or instability. The datasheet explicitly warns against DC coupling; recommended input coupling capacitors are ≥0.01µF for 8B/10B data (e.g., Fibre Channel) and ≥0.1µF for scrambled NRZ (e.g., SONET), based on low-frequency cutoff calculations.