Analog Devices Inc. HMC347B

Overview

HMC347B from Analog Devices is a GaAs pHEMT SPDT monolithic microwave integrated circuit (MMIC) switch designed for broadband RF signal routing. It operates from 0.1 GHz to 20 GHz with 1.7 dB typical insertion loss, 46 dB typical isolation, and requires dual negative control voltages (−5 V or 0 V) with zero supply current-used in VSAT front-ends and ECM systems.

For engineers reviewing the HMC347B datasheet, HMC347B pinout, HMC347B application, or HMC347B equivalent, this page delivers verified broadband switch specifications, nonreflective 50 Ω architecture details, thermal resistance values (θJC = 118 °C/W through path), truth table–driven control logic, and die-level mounting guidance for millimeter-wave integration.

Technical Context

The HMC347B implements on-chip via hole structures to achieve nonreflective 50 Ω termination across 0.1–20 GHz, enabling high isolation without external matching. Its SPDT topology uses complementary CTRLA/CTRLB logic to select RFC↔RF1 or RFC↔RF2 paths while terminating the inactive throw to an internal 50 Ω resistor.

Operation requires no DC supply-only two negative voltage digital inputs (−5 V/0 V), delivering 25 dBm input P1dB and 41 dBm IP3 at 25°C. Switching speed is characterized by 3 ns rise/fall time and 10 ns on/off time, with thermal performance dependent on die-bottom grounding to RF ground per C-10-10 bare-die package requirements.

Key Specifications

Pinout & Package

Package: 10-pad bare die [CHIP], C-10-10 outline (1.30 mm × 0.85 mm × 0.102 mm), back-metallized for direct attachment to RF ground plane using AuSn eutectic or conductive epoxy.

Key Features

Applications

Equivalent & Alternatives

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

Compared with HMC347B, HMC347LP3E offers simplified assembly at the expense of thermal performance (θJC ≈ 180 °C/W vs. 118 °C/W), while QM11030 trades low-frequency coverage and power handling for lower unit cost and standard packaging-neither is pin-compatible, requiring layout revision for substitution.

Availability

HMC347B is available at Aetrix Electronics and suitable for VSAT front-ends, military radar T/R modules, and electronic warfare ECM systems requiring stable component supply across extended temperature ranges (−55°C to +85°C) and long-lifecycle programs.

Supply support for HMC347B 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 leader in high-performance analog, mixed-signal, and RF ICs, serving precision instrumentation, communications, and defense markets since 1965.

The HMC347B belongs to Analog Devices' legacy Hittite Microwave MMIC product line, engineered specifically for broadband nonreflective switching in demanding defense and test equipment applications where zero-supply operation and Ka-band performance are critical.

FAQ

What is the control voltage requirement for the HMC347B?

The HMC347B requires two negative control voltages applied to CTRLA and CTRLB pins: −5 V (logic high) or 0 V (logic low). No positive supply is needed, and current draw is zero. The truth table defines RFC↔RF1 conduction when CTRLA = −5 V and CTRLB = 0 V, and RFC↔RF2 when CTRLA = 0 V and CTRLB = −5 V. This dual-negative logic eliminates level-shifting circuitry in HMC347B designs.

Does the HMC347B require DC blocking capacitors on its RF ports?

Yes-the HMC347B RF pads (RFC, RF1, RF2) are DC-coupled to 0 V, so blocking capacitors are required if the connected RF transmission line operates at a non-zero DC potential. When the line is at 0 V, no DC blocking is necessary. This applies equally to all three RF ports and must be verified per system biasing scheme before integrating the HMC347B into a final design.

What is the thermal resistance (θJC) of the HMC347B, and how does it affect power handling?

The HMC347B has θJC = 118 °C/W for the through path and 200 °C/W for the terminated path, measured junction-to-case bottom. Because the die bottom must be bonded directly to RF ground, thermal performance depends entirely on substrate material, bonding method (AuSn or conductive epoxy), and ground plane area. Exceeding 27 dBm in the through path risks junction temperatures above 150°C unless thermal design meets spec-this is critical for sustained HMC347B operation in radar transmitters.

Can the HMC347B be used in bidirectional RF signal paths?

Yes-the HMC347B is fully bidirectional: RF signals may be applied to RFC with RF1/RF2 as outputs, or applied to RF1/RF2 with RFC as the output. Its symmetric nonreflective 50 Ω architecture ensures identical insertion loss and isolation in either direction. This makes the HMC347B suitable for both T/R switching and signal routing applications where path reversal occurs during system calibration or duplex operation.

What mounting method is required for the HMC347B bare die?

The HMC347B must be mounted with its metallized die bottom bonded directly to an RF ground plane using gold-tin (AuSn) eutectic preforms or electrically conductive epoxy. Ribbon bonds (3 mil × 0.5 mil) to RF pads and 1 mil wire bonds to control pads are recommended. Substrate thickness dictates mechanical offset: 5 mil alumina requires direct die attach; 10 mil alumina requires a 6 mil molybdenum heat spreader to maintain coplanarity-per HMC347B assembly guidelines.