Analog Devices Inc. HMC344-SX

Overview

HMC344-SX 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 insertion loss at 6 GHz, 44 dB isolation at 2 GHz, and -5 V fixed bias with TTL-compatible dual-control inputs (A/B). It serves as a broadband RF signal routing element in microwave front-ends requiring high linearity and compact die form.

For engineers reviewing the HMC344-SX datasheet, HMC344-SX pinout, HMC344-SX application, or HMC344-SX equivalent, key selection criteria include its non-reflective topology, 21 dBm input P1dB, 40 dBm IIP3, 35 ns RF rise time, and compatibility with -5 V system bias rails and TTL logic interfaces.

Technical Context

The HMC344-SX implements a monolithic GaAs MESFET SP4T architecture with integrated 2:4 binary decoder, reducing control lines from four to two. Its non-reflective design terminates unused ports internally to 50 Ω, eliminating external termination components.

It operates with fixed -5 V Vee bias and accepts TTL-level control voltages (–3 V to 0 V for Low, –5 V to +4.2 V for High), enabling direct interfacing with standard logic without level-shifting. Thermal resistance of the insertion loss path is 143 °C/W, supporting operation from –55 °C to +85 °C.

Key Specifications

Pinout & Package

Package: Bare die, 1.08 × 1.05 × 0.10 mm, gold metallized bond pads, grounded backside, 0.004″ square pads on 0.006″ pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with HMC344LC3 and QM11035, the HMC344-SX offers superior high-frequency performance (DC–8 GHz), lowest insertion loss, and non-reflective architecture-but requires wire-bond assembly and negative bias, making it optimal for high-performance microwave hybrids rather than volume SMT production.

Availability

HMC344-SX is available at Aetrix Electronics and suitable for telecom infrastructure, microwave radio & VSAT, military & space radios, and test instrumentation requiring stable component supply and traceable GaAs MMIC sourcing.

Supply support for HMC344-SX 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 is a global semiconductor leader specializing in high-performance analog, mixed-signal, and RF technologies for precision signal processing.

The HMC344-SX belongs to the former Hittite Microwave GaAs MMIC switch product line, engineered for broadband, high-isolation, low-distortion RF signal routing in demanding microwave communication systems.

FAQ

What is the operating frequency range of the HMC344-SX?

The HMC344-SX operates from DC to 8 GHz, covering L-, S-, C-, and lower X-bands. This full-range capability is verified per datasheet testing in 50 Ω fixtures with minimal-length wire bonds. The HMC344-SX maintains specified insertion loss, isolation, and linearity across this entire span, making it suitable for wideband microwave applications without band segmentation.

Does the HMC344-SX require external termination resistors?

No, the HMC344-SX uses a non-reflective topology with internal 50 Ω terminations on unselected ports. This eliminates the need for external resistors, simplifying PCB layout and improving repeatability. The HMC344-SX achieves this via integrated GaAs MESFET termination networks, confirmed in the functional diagram and electrical specifications section of the datasheet.

What control voltage levels are compatible with the HMC344-SX A and B inputs?

The HMC344-SX A and B inputs accept TTL-compatible logic: Low = –3 V to 0 V (60 µA typical sink), High = –5 V to +4.2 V (5 µA typical source). This allows direct interface with HCT logic families powered from –5 V Vee, as shown in the TTL Interface Circuit schematic. The HMC344-SX does not require level shifters when used in properly biased negative-rail systems.

What is the thermal resistance of the HMC344-SX under RF signal conditions?

The HMC344-SX has a thermal resistance of 143 °C/W for the insertion loss path and 1,030 °C/W for the terminated path. These values are measured per JEDEC standards and reflect junction-to-case performance under RF power dissipation. The HMC344-SX's low 143 °C/W value supports reliable operation at +85 °C ambient with 21 dBm input power, as validated in thermal characterization plots.

Is the HMC344-SX pin-compatible with the HMC344LC3 package variant?

No, the HMC344-SX is a bare die while the HMC344LC3 is a 16-lead SMT package with different pad layout and mechanical interface. Though both contain identical GaAs MMIC functionality, the HMC344-SX requires wire bonding to substrate pads, whereas the HMC344LC3 uses solder reflow. The HMC344-SX cannot be substituted for HMC344LC3 without redesigning the RF interconnect and assembly process.