Analog Devices Inc./Maxim Integrated MAX3980UTH+

Overview

MAX3980UTH+ from Maxim Integrated is a quad-channel adaptive CML equalizer IC designed for 3.125Gbps XAUI receiver-side signal conditioning in 10GbE backplane systems. It delivers 40in FR-4 trace compensation, 175mW/channel power consumption at +3.3V, and integrated signal detect (SDET) on Channel 1. It operates across 0°C to +85°C and supports IEEE-802.3ae-compliant 10GbE MAC-to-PMD links.

For engineers reviewing the MAX3980UTH+ datasheet, MAX3980UTH+ pinout, MAX3980UTH+ application, or MAX3980UTH+ equivalent, key selection criteria include differential CML I/O impedance (100Ω), adaptive equalization for media-induced ISI, latency (0.32ns), deterministic jitter reduction (≤0.2 UI_p-p), and standby mode control via TTL EN pin.

Technical Context

The MAX3980UTH+ implements a master-slave adaptive equalization architecture: only Channel 1 (IN1±/OUT1±) hosts full signal-detect, control-loop, and limiting functions; Channels 2–4 are slave equalizers sharing the master's adaptation voltage. This ensures matched equalization across all four lanes without per-channel calibration overhead.

It accepts and regenerates 3.125Gbps NRZ data using CML I/O with 100Ω differential input/output impedance, common-mode voltage of V_CC – 0.3V, and requires AC coupling. Signal detect asserts at ≥100mV_p-p differential input on IN1± and deasserts below 30mV_p-p, operating independently of EN state.

Key Specifications

Pinout & Package

The MAX3980UTH+ is housed in a 44-pin TQFN-EP (thin quad flat no-lead with exposed pad) package, 7mm × 7mm × 0.8mm, requiring soldering of the exposed pad to PCB ground for thermal and electrical performance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad-channel high-speed equalizer applications.

Compared with MAX3981UTH+, the MAX3980UTH+ offers lower power and simpler control at the expense of per-channel monitoring; versus DS25BR120TSQ, it provides adaptive compensation essential for variable-length or aging backplanes, though with higher design integration effort.

Availability

MAX3980UTH+ is available at Aetrix Electronics and suitable for 10GbE backplane interconnects, XAUI interface extension, and InfiniBand SM link conditioning requiring stable component supply, RoHS-compliant packaging, and long-term industrial temperature support (0°C to +85°C).

Supply support for MAX3980UTH+ 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 demanding communications, computing, and industrial applications.

The MAX3980UTH+ belongs to Maxim's high-speed serial interface product line, engineered specifically for XAUI and InfiniBand receiver equalization in backplane and midplane architectures where signal integrity degradation must be actively corrected.

FAQ

What is the primary function of the MAX3980UTH+ in a 10GbE system?

The MAX3980UTH+ acts as a quad-channel adaptive receiver equalizer that compensates for high-frequency loss in FR-4 backplane traces up to 40in, restoring signal integrity for 3.125Gbps XAUI lanes. It reduces intersymbol interference and deterministic jitter before clock-data recovery, enabling reliable 10GbE MAC-to-PMD communication. The MAX3980UTH+ achieves this with matched 0.32ns latency across all four channels and integrated signal detect on Channel 1.

Does the MAX3980UTH+ require external configuration or tuning?

No, the MAX3980UTH+ operates autonomously with fully adaptive equalization controlled internally by Channel 1's signal-detect and control loop. No external resistors, capacitors, or digital configuration are needed. The adaptive algorithm continuously adjusts equalization strength based on spectral content of the incoming signal, optimized for 8b/10b encoded data. The MAX3980UTH+ is ready to operate immediately upon power-up and EN assertion.

How does the signal detect (SDET) function work on the MAX3980UTH+?

The SDET pin on the MAX3980UTH+ outputs a TTL-high signal when the differential peak-to-peak voltage at IN1± exceeds 100mV_p-p, and goes low when it falls below 30mV_p-p. This function operates independently of the EN pin state, remaining active even in standby mode. The MAX3980UTH+ uses this to indicate valid signal presence on Channel 1 only, supporting automatic link-up detection or wake-on-signal configurations when SDET is tied to EN.

Can the MAX3980UTH+ be used with data rates other than 3.125Gbps?

Yes, the MAX3980UTH+ supports data rates from 2Gbps to 4Gbps when used with short-run DC-balanced codes like 8b/10b. Its equalization is optimized for 3.125Gbps and 40in FR-4, but the adaptive architecture maintains effectiveness across this range. Performance metrics such as jitter and eye opening are specified at 3.125Gbps; for other rates, validation against actual channel loss profile is recommended. The MAX3980UTH+ does not require reconfiguration for rate changes within this window.

What are the thermal requirements for the MAX3980UTH+ in continuous operation?

The MAX3980UTH+ dissipates 700mW at +3.3V and requires proper thermal management via its exposed pad (EP), which must be soldered to a solid PCB ground plane. At +85°C ambient, its maximum continuous power dissipation is 2105mW with 26.3mW/°C derating above that temperature. Layout best practices include placing ≥4x 0.1µF ceramic decoupling capacitors near each VCC pin group and minimizing thermal resistance between EP and internal ground planes. The MAX3980UTH+ is rated for 0°C to +85°C operation with no thermal derating required under these conditions.