Analog Devices Inc. HMC871LC5TR

Overview

HMC871LC5TR from Analog Devices (formerly Hittite Microwave) is a GaAs MMIC distributed driver amplifier optimized for EA optical modulator biasing and high-speed data transmission. It delivers 15 dB gain from DC to 20 GHz, adjustable 4 V_p-p saturated output swing, ±0.5 dB gain flatness, and <300 fs additive RMS jitter at 10–22.5 Gbps - enabling precise eye shaping in 10G/40G optical transmitters.

For engineers reviewing the HMC871LC5TR datasheet, HMC871LC5TR pinout, HMC871LC5TR application, or HMC871LC5TR equivalent, key selection criteria include its 5–8 V wide supply range, internal 50 Ω I/O matching, cross-point adjustability, low power dissipation (<0.25 W at 2.5 V_p-p), and 32-lead 5×5 mm SMT package with exposed ground paddle.

Technical Context

The HMC871LC5TR employs a GaAs PHEMT distributed amplifier architecture with cascode gain stages and on-chip broadband matching networks. Its DC-coupled 50 Ω input and output interfaces support direct integration into optical transmitter signal paths without external AC coupling or impedance transformation.

It features three independent bias controls: Vdd (5–8 V), Vgg (−2 to 0 V) for drain current tuning (50–75 mA), and VC (0–2 V) for output amplitude and cross-point adjustment. Gain flatness and group delay variation (±15 ps over 1–12 GHz) are maintained across temperature (−40°C to +85°C) and supply voltage.

Key Specifications

Pinout & Package

The HMC871LC5TR is housed in a leadless 5×5 mm surface-mount ceramic QFN package (alumina body, gold-over-nickel plating, MSL3). The exposed ground paddle must be soldered to the PCB RF ground plane using ≥9 thermal vias for optimal thermal and RF performance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar optical modulator driver applications.

Compared with HMC871LC5TR, HMC981LP5E extends bandwidth and output power for next-generation coherent optics, while LMH5401RTVT offers silicon-based simplicity and lower voltage operation at the expense of jitter performance and analog control granularity.

Availability

HMC871LC5TR is available at Aetrix Electronics and suitable for SONET OC-192 transmission systems, 10GBASE-LR optical modules, and 40G DQPSK pre-driver designs requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for HMC871LC5TR 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

Analog Devices acquired Hittite Microwave in 2014 and integrates its high-frequency RF/microwave portfolio into precision analog and RF solutions for communications infrastructure.

The HMC871LC5TR belongs to the Hittite optical modulator driver product line, engineered specifically for high-speed fiber-optic transmitters demanding ultra-low jitter, wide bandwidth, and precise analog control of optical eye shape.

FAQ

What is the recommended power-up sequence for the HMC871LC5TR?

Apply ground first, then set Vgg to −2 V and VC to +0.5 V before enabling Vdd (5 V or 8 V). Adjust Vgg to achieve target Idd (50 mA at 5 V, 75 mA at 8 V), then apply RF input. This prevents gate overstress and ensures stable bias point establishment. The HMC871LC5TR must never be powered with RF applied before bias stabilization.

Does the HMC871LC5TR require external AC coupling capacitors on RFIN and RFOUT?

Yes - both RFIN (Pin 5) and RFOUT (Pin 22) are DC-coupled but require external AC coupling capacitors (e.g., 100 nF X7R 0402) to block DC offsets from adjacent stages. This is mandatory per the application circuit; omitting them risks saturation or improper bias point shift. The HMC871LC5TR itself contains no internal blocking caps.

How does VC voltage affect the output eye diagram of the HMC871LC5TR?

VC (Pin 2) directly controls output amplitude and cross-point percentage: 0.5 V yields nominal 4 V_p-p swing and 50% crossing, while varying VC from 0 to 2 V adjusts swing from ~2.5 to 4 V_p-p and cross-point from ~30% to 70%. This enables real-time optimization of extinction ratio and eye height in closed-loop optical systems. The HMC871LC5TR's VC interface is analog and monotonic across its full range.

What thermal management is required for continuous operation of the HMC871LC5TR at 75 mA?

At 75 mA and 8 V (0.6 W dissipation), the HMC871LC5TR requires soldering its exposed ground paddle to a minimum 100 mm² copper area with ≥9 thermal vias (0.3 mm diameter) to an internal ground plane. Without this, junction temperature exceeds 125°C at +85°C ambient. The HMC871LC5TR's 66.31 °C/W thermal resistance assumes full paddle attachment per datasheet layout guidelines.

Can the HMC871LC5TR be used with 3.3 V supply rails?

No - the HMC871LC5TR has an absolute minimum Vdd of +5 V and maximum of +9 V. Operation below 5 V violates absolute maximum ratings and results in insufficient gain, poor output swing, and unstable bias. For 3.3 V systems, consider alternatives like LMH5401RTVT. The HMC871LC5TR is not rated nor characterized for sub-5 V operation.