Analog Devices Inc./Maxim Integrated MAX3784AUTE+

Overview

The MAX3784AUTE+ from Maxim Integrated is a 5Gbps adaptive PCB equalizer IC designed to compensate for FR-4 transmission losses up to 40 inches, optimized for 8b10b-encoded 4×1.25Gbps Ethernet and 4.25Gbps Fibre Channel backplane interconnects. It features CML differential I/O, standby mode, +3.3V single-supply operation, and delivers 0.18UI deterministic jitter at 5Gbps over 40in FR-4.

For engineers reviewing the MAX3784AUTE+ datasheet, MAX3784AUTE+ pinout, MAX3784AUTE+ application, or MAX3784AUTE+ equivalent, key selection criteria include deterministic jitter performance at 1.25/2.5/5Gbps, CML input/output compatibility, EN-controlled standby functionality, thermal management via exposed-pad grounding, and TQFN-EP package layout requirements.

Technical Context

The MAX3784AUTE+ implements an adaptive equalization control loop that detects input signal spectral content to dynamically adjust equalizer gain, targeting frequency-dependent loss compensation in NRZ and 8b10b data streams. Its limiting output driver ensures clean CML-level signaling with 550–750mV_P-P differential swing.

It operates exclusively with current-mode logic (CML) interfaces-requiring AC coupling when interfacing to lower-voltage terminations-and relies on a dedicated EN pin to switch between active mode (EN high/open) and low-power standby (EN low), reducing supply current to 30mW.

Key Specifications

Pinout & Package

The MAX3784AUTE+ is housed in a 4mm × 4mm, 16-pin TQFN-EP package (pkg code T1644-3) with an exposed thermal pad requiring soldering to PCB ground for electrical integrity and thermal dissipation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PCB equalizer applications.

Compared with MAX3784UTE+ and LMH0384SQ/NOPB, the MAX3784AUTE+ provides adaptive equalization, higher output drive, and guaranteed 5Gbps performance over 40in FR-4-making it the only option for thermally constrained, high-density 5Gbps backplane upgrades requiring zero layout changes.

Availability

MAX3784AUTE+ is available at Aetrix Electronics and suitable for 4.25Gbps Fibre Channel backplanes, 4×1.25Gbps Ethernet multiplexing, and high-density switch fabric interconnects requiring stable component supply across extended product lifecycles.

Supply support for MAX3784AUTE+ 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 interface ICs for industrial, communications, and computing applications.

The MAX3784AUTE+ belongs to Maxim's high-speed signal conditioning product line, engineered specifically for DC-balanced NRZ/8b10b backplane equalization in telecom line cards and storage systems.

FAQ

What is the maximum FR-4 trace length supported by the MAX3784AUTE+ at 5Gbps?

The MAX3784AUTE+ is characterized to support up to 40 inches of 6-mil edge-coupled FR-4 stripline at 5Gbps while maintaining ≤0.18UI deterministic jitter. This specification assumes standard FR-4 material properties (ε_r = 4.4–4.5, loss tangent = 0.02–0.022) and proper layout including controlled impedance and exposed-pad grounding. Performance beyond 40in is not guaranteed and requires system-level validation. The MAX3784AUTE+ achieves this via adaptive equalization optimized for short-run, balanced codes like 8b10b.

How does the MAX3784AUTE+ differ from the MAX3784UTE+?

The MAX3784AUTE+ delivers higher differential output voltage swing (550–750mV_P-P) versus the MAX3784UTE+ (400–600mV_P-P) and lower residual deterministic jitter (0.18UI vs. 0.21UI at 5Gbps over 40in FR-4). Both share identical pinout, package (TQFN-EP), and standby functionality. The MAX3784AUTE+ is the recommended choice for designs requiring tighter jitter budgets or longer trace reach, while the MAX3784UTE+ remains viable for cost-sensitive, shorter-channel applications.

Can the MAX3784AUTE+ operate at data rates other than 5Gbps?

Yes, the MAX3784AUTE+ supports 1.25Gbps and 2.5Gbps operation with documented deterministic jitter performance: 0.07UI (max) at 1.25Gbps/40in and 0.13UI (max) at 2.5Gbps/40in. Its adaptive equalization loop automatically adjusts to these rates without configuration. However, the device is optimized for 5Gbps, and jitter performance degrades progressively below 1.25Gbps. For reliable operation, input signals must comply with CML voltage swing (400–1000mV_P-P) and 8b10b or NRZ coding.

What is the role of the exposed pad (EP) on the MAX3784AUTE+ package?

The exposed pad (EP) on the MAX3784AUTE+ TQFN-EP package must be soldered directly to the PCB's solid ground plane. It serves dual functions: (1) thermal conduction-reducing junction-to-board thermal resistance to <1.5°C/W-and (2) electrical grounding-providing a low-inductance return path critical for CML signal integrity and jitter suppression. Failure to solder the EP results in excessive junction temperature (>110°C at full load) and increased deterministic jitter (>0.25UI), violating datasheet specifications. The MAX3784AUTE+ datasheet explicitly mandates this connection.

Is AC coupling required when interfacing the MAX3784AUTE+ with non-CML devices?

Yes, AC coupling is mandatory when connecting the MAX3784AUTE+ to devices with different common-mode voltages (e.g., LVDS at +1.2V or PECL at V_CC − 1.3V). The MAX3784AUTE+ CML I/O operates with a common-mode voltage >+2.5V, so direct DC coupling would violate input/output voltage limits of lower-voltage interfaces. Use ≥0.10µF high-frequency ceramic capacitors placed within 5mm of the MAX3784AUTE+ pins. No AC coupling is needed between two CML devices sharing the same +3.3V supply and termination scheme.