Analog Devices Inc. HMC344

Overview

HMC344 from Analog Devices (formerly Hittite Microwave) is a GaAs MMIC SP4T non-reflective switch chip operating from DC to 8 GHz, delivering 1.8 dB typical insertion loss at 6 GHz, 44 dB isolation at 2 GHz, and TTL-compatible dual-control logic (A/B) with integrated 2:4 decoder. It serves as a broadband RF signal routing element in microwave front-ends requiring high isolation and low-loss path selection.

For engineers reviewing the HMC344 datasheet, HMC344 pinout, HMC344 application, or HMC344 equivalent, key selection criteria include its -5 V fixed bias requirement, 0/–5 V control voltage range, 150 ns switching time, non-reflective topology for impedance stability during state transitions, and die-level form factor requiring wire-bond assembly.

Technical Context

The HMC344 implements a monolithic GaAs MESFET architecture with on-die binary decoder, reducing external control lines from four to two. Its non-reflective design terminates unused ports internally to 50 Ω, ensuring stable VSWR across all states without external matching networks.

It operates with fixed –5 Vdc bias (Vee) and TTL-level control inputs referenced to Vee, supporting direct interface to HCT logic when Vee is shared. Thermal resistance of 143 °C/W (insertion loss path) and 1,030 °C/W (terminated path) reflects asymmetric power dissipation behavior between active and isolated paths.

Key Specifications

Pinout & Package

Package: Bare die, 1.08 × 1.05 × 0.10 mm, gold metallized bond pads, grounded backside, 0.004″ die thickness. Requires wire bonding using 0.025 mm (1 mil) diameter wires ≤0.31 mm (12 mils) length in 50 Ω test fixture.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar SP4T RF switch applications.

Compared with HMC547LP3E and QM11036, the HMC344 offers wider bandwidth (DC–8 GHz), integrated decoder, and non-reflective architecture-critical for broadband test equipment and military EW systems-but requires wire-bond assembly and negative bias, limiting use in cost-sensitive commercial SMT designs.

Availability

HMC344 is available at Aetrix Electronics and suitable for telecom infrastructure, microwave radio & VSAT, and military & space applications requiring stable component supply and long-term availability of GaAs MMIC die.

Supply support for HMC344 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 maintains its high-frequency RF portfolio, specializing in GaAs, GaN, and SiGe MMICs for demanding wireless and defense applications.

The HMC344 belongs to Hittite's legacy SPnT switch product line, engineered specifically for broadband non-reflective RF signal routing in microwave front-ends where impedance stability and wideband performance are critical.

FAQ

What is the recommended bias configuration for HMC344?

The HMC344 requires a fixed –5 Vdc supply (Vee) applied to pad 8, with ±10% tolerance. This same –5 V rail must also be connected to the Vee pin of any interfacing HCT logic gates to ensure proper TTL-level control. Decoupling capacitors near Vee and ground are essential to suppress switching noise and maintain stable operation across DC–8 GHz.

Does HMC344 support DC-coupled RF operation?

Yes, the HMC344 supports true DC-coupled RF operation on all ports (RFC, RF1–RF4). However, external DC-blocking capacitors are required on each RF port if the connected circuitry cannot tolerate DC bias, as the switch itself does not provide internal blocking. The die's DC-coupled design enables baseband and low-frequency signal routing down to 0 Hz.

Can HMC344 be used with CMOS logic instead of TTL?

HMC344 can interface with CMOS logic only if the CMOS device supports negative voltage swing (–3 V to 0 V for Low, –5 V to +4.2 V for High) and shares the –5 V Vee reference. Standard 3.3 V or 5 V CMOS outputs are incompatible without level-shifting circuitry due to the HMC344's negative-voltage control architecture.

What thermal considerations apply to HMC344 in continuous RF operation?

In continuous operation, HMC344 exhibits 143 °C/W thermal resistance on the insertion loss path and 1,030 °C/W on the terminated path. To avoid exceeding the 150 °C channel temperature limit, the die bottom must be soldered or eutectically bonded to a thermally conductive ground plane with low thermal impedance, especially when handling >+17 dBm average input power.

Is there an SMT-packaged version of HMC344 available?

Yes-the HMC344LC3 is the surface-mount packaged variant of the HMC344, offered in a leadless ceramic chip carrier (LC3) format. It retains identical electrical specifications and functionality but replaces wire-bond assembly with standard reflow-solderable terminations, simplifying manufacturing for high-volume PCB production.