Analog Devices Inc. HMC346LC3BTR-R5

Overview

HMC346LC3BTR-R5 from Analog Devices (formerly Hittite Microwave) is a GaAs MMIC voltage-variable attenuator operating from DC to 18 GHz, providing 30 dB analog attenuation range with low phase shift variation, 2.7 dB typical insertion loss at 14 GHz, and single-voltage control (0 to –3 V). It serves as an absorptive RF signal level controller in microwave test instrumentation and broadband telecom front-ends.

For engineers reviewing the HMC346LC3BTR-R5 datasheet, HMC346LC3BTR-R5 pinout, HMC346LC3BTR-R5 application, or HMC346LC3BTR-R5 equivalent, key selection criteria include its DC–18 GHz bandwidth, 3×3 mm RoHS-compliant ceramic SMT package, 10 dB minimum return loss, +25 dBm input IP3 at minimum attenuation, and compatibility with surface-mount manufacturing.

Technical Context

The HMC346LC3BTR-R5 implements an absorptive architecture with on-chip reference attenuator and integrated bias network, enabling stable impedance match across 30 dB attenuation range without external matching components. Its control interface uses dual-input voltage pins (V1/V2) for master control and a slave input (I), supporting external op-amp-based single-line driver circuits.

Designed for DC-coupled 50 Ω RF paths, it requires blocking capacitors when RF line DC potential deviates from 0 V. The device maintains ≤2.5° relative phase shift variation over 30 dB attenuation at 10 GHz and exhibits 2 ns rise/fall time with 8 ns turn-on/turn-off delay under 50% control-to-RF timing definition.

Key Specifications

Pinout & Package

Package: 3 × 3 mm ceramic leadless SMT package (alumina body, gold-over-nickel plating, MSL3, exposed ground paddle).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar voltage-variable attenuator applications.

Compared with HMC346LC3BTR-R5, HMC1084LP3E extends usable frequency but sacrifices linearity and control flexibility, while QM11024 offers digital integration at the expense of bandwidth and DC coupling - making HMC346LC3BTR-R5 the optimal choice for DC–18 GHz analog-controlled RF leveling.

Availability

HMC346LC3BTR-R5 is available at Aetrix Electronics and suitable for test instrumentation, fiber optics & broadband telecom, and microwave radio & VSAT applications requiring stable component supply, consistent RF performance, and RoHS-compliant SMT manufacturability.

Supply support for HMC346LC3BTR-R5 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 portfolio into precision RF signal chain solutions for defense, communications, and instrumentation markets.

The HMC346LC3BTR-R5 belongs to Hittite's GaAs MMIC voltage-variable attenuator product line, designed specifically for broadband analog RF amplitude control in DC–18 GHz systems where low phase distortion and absorptive termination are critical.

FAQ

What is the operating temperature range for the HMC346LC3BTR-R5?

The HMC346LC3BTR-R5 operates from –40 °C to +85 °C and is characterized over this full range. Electrical specifications such as insertion loss, attenuation range, and return loss are guaranteed at +25 °C, with performance curves provided for –40 °C and +85 °C in the datasheet. Thermal derating is not required within this envelope, and the 3×3 mm ceramic package supports reliable solder joint integrity under thermal cycling.

Does the HMC346LC3BTR-R5 require external blocking capacitors on its RF ports?

Yes, the HMC346LC3BTR-R5 RF1 and RF2 pins are DC-coupled and matched to 50 Ω, so external DC-blocking capacitors are required whenever the RF line DC potential differs from 0 V. This prevents unintended bias injection into the MMIC core and ensures proper attenuation linearity. Typical values range from 100 pF to 1 nF depending on low-frequency cutoff requirements.

Can the HMC346LC3BTR-R5 be used with positive-only control voltage supplies?

No - the HMC346LC3BTR-R5 requires a negative control voltage swing from 0 V down to –3 V for full 30 dB attenuation range. It does not support positive-only control schemes. An external op-amp configured as an inverting amplifier or level shifter is necessary when driving from a unipolar DAC or microcontroller output.

What is the meaning of "absorptive" in the HMC346LC3BTR-R5 datasheet?

"Absorptive" means the HMC346LC3BTR-R5 terminates excess RF energy internally rather than reflecting it back toward the source. This maintains stable 50 Ω input/output impedance across all attenuation settings, preventing gain ripple in cascaded stages and avoiding instability in sensitive oscillator or amplifier circuits - a key advantage over reflective MMIC attenuators.

Is the exposed ground paddle on the HMC346LC3BTR-R5 package required to be soldered?

Yes - the exposed metal ground paddle on the bottom of the HMC346LC3BTR-R5 package must be soldered to the PCB RF ground plane. This connection is essential for achieving specified RF performance, including return loss ≥10 dB and thermal dissipation up to +85 °C. Failure to solder the paddle results in degraded matching, increased insertion loss, and potential thermal overstress.