Analog Devices Inc. HMC870LC5TR

Overview

HMC870LC5TR from Analog Devices (formerly Hittite Microwave) is a GaAs MMIC pHEMT distributed driver amplifier optimized for MZ optical modulator biasing in high-speed fiber-optic transmission systems. It delivers 17 dB gain, 8 V_p-p saturated output swing, and <300 fs additive RMS jitter at 10 Gbps, operating DC–20 GHz with 50 Ω RF I/Os internally matched. Its cross-point adjustment and scalable power dissipation (<0.4 W at 3.6 V_p-p, <1 W at 8.5 V_p-p) support metro/long-haul coherent transceivers.

For engineers reviewing the HMC870LC5TR datasheet, HMC870LC5TR pinout, HMC870LC5TR application, or HMC870LC5TR equivalent, key selection criteria include its 20 GHz small-signal bandwidth, adjustable 2.5–8 V_p-p output swing via Vctl, ±0.5 dB gain flatness, low group delay variation (±15 ps), and compatibility with NRZ/RZ and DQPSK modulation formats up to 40 Gbps.

Technical Context

The HMC870LC5TR employs a distributed amplifier architecture with cascaded pHEMT gain stages enabling broadband DC–20 GHz operation. Its gain flatness (±0.5 dB) and low group delay variation (±15 ps over 1–12 GHz) are achieved through precise impedance matching and phase compensation across the signal path.

It features three independent bias controls: Vgg sets drain current (140–165 mA), Vctl adjusts output amplitude (0–2 V), and Vdd supplies 3.3–7 V, enabling dynamic power–performance trade-offs. The RFOUT/Vdd pin integrates DC bias injection and RF output routing, requiring external broadband bias tee implementation per application circuit.

Key Specifications

Pinout & Package

Package: 32-lead, 5×5 mm leadless surface-mount package with alumina body, gold-over-nickel plating, and exposed ground paddle. MSL3 rated; max reflow 260 °C.

Key Features

Applications

Equivalent & Alternatives

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

Compared with HMC870LC5TR, HMC988LP5E offers wider bandwidth at the expense of amplitude adjustability, while LMH5401RTVT trades bandwidth and tuning for lower power and cost-making HMC870LC5TR the balanced choice for scalable, high-fidelity MZ drive across metro/long-haul platforms.

Availability

HMC870LC5TR is available at Aetrix Electronics and suitable for 10 Gbps NRZ, 40 Gbps DQPSK, and RZ optical transmission systems requiring stable component supply, long-lifecycle support, and traceable sourcing for telecom infrastructure deployments.

Supply support for HMC870LC5TR 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 signal chain solutions for communications, defense, and instrumentation.

The HMC870LC5TR belongs to Analog Devices' optical modulator driver product line, engineered specifically for high-speed fiber-optic transceivers demanding ultra-low jitter, wide bandwidth, and flexible output swing in compact SMT packages.

FAQ

What is the maximum output voltage swing supported by the HMC870LC5TR?

The HMC870LC5TR supports an adjustable peak-to-peak output voltage swing from 2.5 V_p-p to 8 V_p-p, achieved by tuning the Vctl pin from 0 V to 2 V. At Vctl = 1 V and Vdd = 7 V, the typical saturated output is 8 V_p-p, verified under 11.25 Gbps NRZ conditions with 1.2 V_p-p input. This range directly drives both low- and high-V_π Mach-Zehnder modulators without external amplification.

How does the HMC870LC5TR achieve low additive RMS jitter?

The HMC870LC5TR achieves <300 fs additive RMS jitter through its GaAs pHEMT distributed amplifier architecture, which minimizes phase noise and nonlinear distortion across DC–20 GHz. Measured with a 22.5 Gbps 10101… pattern, this jitter performance is enabled by internal 50 Ω matching, low group delay variation (±15 ps), and optimized bias stability-ensuring timing integrity in 10/40 Gbps optical links where HMC870LC5TR serves as the final-stage modulator driver.

What is the recommended power-up sequence for the HMC870LC5TR?

The HMC870LC5TR requires strict power sequencing: (1) ground all pins, (2) set Vgg to −2 V (zero drain current), (3) set Vctl to +1 V, (4) apply Vdd = +5 V, then (5) adjust Vgg to achieve target Idd (140–165 mA). This prevents gate overstress and ensures controlled turn-on. The HMC870LC5TR datasheet specifies this sequence to avoid latch-up or permanent damage due to ESD-sensitive GaAs process technology.

Can the HMC870LC5TR operate with a 3.3 V supply?

Yes, the HMC870LC5TR operates across a wide supply range of +3.3 V to +7 V. At Vdd = 3.3 V, it delivers 17.5 dB gain (1–8 GHz), 3.6 V_p-p output, and 0.33 W power dissipation-ideal for thermally constrained modules. Performance metrics including gain flatness (±0.5 dB) and input/output return loss (>20 dB below 10 GHz) remain fully specified, confirming HMC870LC5TR's suitability for low-voltage optical subsystems.

What package type and thermal characteristics does the HMC870LC5TR have?

The HMC870LC5TR uses a 32-lead, 5×5 mm leadless ceramic package with alumina body and exposed ground paddle. Its thermal resistance (channel-to-ground paddle) is 59.4 °C/W, and continuous power dissipation is rated at 1.5 W at 85 °C (derated 24 mW/°C above). The package requires soldering all ground leads and the paddle to a multi-via PCB ground plane-critical for maintaining HMC870LC5TR's RF performance and thermal reliability in optical line cards.