Analog Devices Inc. HMC347B-SX

Overview

HMC347B-SX from Analog Devices is a GaAs pHEMT monolithic microwave integrated circuit (MMIC) SPDT switch designed for broadband RF signal routing in microwave front-ends. It operates from 0.1 GHz to 20 GHz with 1.7 dB typical insertion loss, 46 dB typical isolation, and −5 V/0 V dual negative control logic-requiring no supply current. It is used in VSAT transmit/receive path switching where high linearity and nonreflective 50 Ω termination are critical.

For engineers reviewing the HMC347B-SX datasheet, HMC347B-SX pinout, HMC347B-SX application, or HMC347B-SX equivalent, key selection criteria include its nonreflective architecture, 25 dBm input P1dB, 10-pad bare-die package, thermal resistance (θJC = 118 °C/W through path), and compatibility with gold-tin eutectic die attach on alumina substrates.

Technical Context

The HMC347B-SX implements a nonreflective SPDT topology using GaAs pHEMT transistors with integrated 50 Ω terminations on both RF throw paths. Its operation relies on complementary negative voltage control (CTRLA/CTRLB) to steer RF between RFC and either RF1 or RF2 while maintaining matched impedance across all states.

It features via-hole structures enabling broadband performance up to 20 GHz, achieves <3 ns rise/fall time, and supports bidirectional RF flow. No external bias is required-only two logic-level control inputs-and all RF pads are dc-coupled, requiring blocking capacitors only when RF line potential deviates from 0 V.

Key Specifications

Pinout & Package

The HMC347B-SX is supplied as a 10-pad GaAs MMIC bare die in C-10-10 outline (1.3 mm × 0.85 mm × 0.102 mm), with backside metallization requiring direct connection to RF ground. Die mounting must use AuSn eutectic preform or conductive epoxy on alumina substrate.

Key Features

Applications

Equivalent & Alternatives

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

Compared with HMC347B-SX, HMC347LP3E offers simplified integration but sacrifices bandwidth and zero-bias operation, while QM11036 delivers lower insertion loss below 6 GHz but cannot support Ka-band VSAT or radar applications requiring 20 GHz coverage.

Availability

HMC347B-SX is available at Aetrix Electronics and suitable for microwave radios, VSAT terminals, military radar systems, and broadband test instrumentation requiring stable component supply across extended temperature ranges (−55°C to +85°C) and long-lifecycle programs.

Supply support for HMC347B-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, Inc. is a global leader in high-performance analog, mixed-signal, and RF ICs, serving aerospace, defense, communications, and industrial markets with precision signal processing solutions.

The HMC347B-SX belongs to Analog Devices' Hittite Microwave MMIC product line, engineered specifically for broadband RF switching in demanding microwave and millimeter-wave systems where nonreflective behavior, high linearity, and zero-bias operation are mandatory.

FAQ

What is the control voltage requirement for HMC347B-SX?

HMC347B-SX uses dual negative control inputs: CTRLA and CTRLB accept −5 V (logic low) or 0 V (logic high). No positive supply or current draw is needed. The device implements a truth table where high/low combinations select RF1–RFC or RF2–RFC paths. This zero-bias architecture eliminates external regulators and simplifies system power design.

Does HMC347B-SX require dc blocking capacitors on its RF pads?

Yes - HMC347B-SX RF pads (RFC, RF1, RF2) are dc-coupled to 0 V. Blocking capacitors are required whenever the connected RF transmission line carries a dc bias voltage other than 0 V. In grounded-coplanar-waveguide or 50 Ω microstrip layouts referenced to RF ground, no blocking is needed; otherwise, chip capacitors must be placed adjacent to each RF pad.

How is thermal management handled for HMC347B-SX?

HMC347B-SX requires direct die-attach of its metallized bottom to an RF ground plane using AuSn eutectic preform or conductive epoxy. Thermal resistance is specified as θJC = 118 °C/W (through path) and 200 °C/W (terminated path). Effective heat extraction depends on substrate material (e.g., 5 mil alumina), bond quality, and ground plane copper thickness - poor thermal contact degrades P1dB and reliability.

Can HMC347B-SX be used in hot-switching configurations?

Yes - HMC347B-SX supports hot switching at up to 23 dBm (VCTL = −5 V or 0 V) across 0.5–20 GHz. This capability allows RF path reconfiguration while signal is present, which is essential in TDD systems and adaptive radar waveforms. Exceeding 23 dBm during switching risks permanent degradation of pHEMT channels.

What is the recommended RF interconnect method for HMC347B-SX?

HMC347B-SX uses ribbon bonding: 3 mil × 0.5 mil gold ribbon for RF pads (RFC, RF1, RF2) and 1 mil diameter gold wire for CTRLA/CTRLB. Bond length must be minimized (< 3 mil nominal gap) to preserve 20 GHz performance. Microstrip lines on 5 mil alumina thin-film substrates are recommended; substrate thickness dictates use of molybdenum heat spreader for coplanarity at 10 mil thickness.