Analog Devices Inc. HMC347A

Overview

HMC347A from Analog Devices is a GaAs pHEMT monolithic microwave SPDT switch operating from 0.1 GHz to 20 GHz, delivering <2.0 dB insertion loss and >40 dB isolation across full bandwidth, with nonreflective 50 Ω architecture and dual negative control voltage inputs (−5 V/0 V). It serves as a high-linearity RF path selector in broadband test instrumentation and military radar front-ends.

For engineers reviewing the HMC347A datasheet, HMC347A pinout, HMC347A application, or HMC347A equivalent, key selection criteria include its 29 dBm input P1dB, 45 dBm IP3, 10-pad CHIP package, −55°C to +85°C operating range, and nonreflective termination for impedance-stable switching in microwave signal routing.

Technical Context

The HMC347A implements on-chip via-hole structures to achieve broadband nonreflective behavior, enabling simultaneous high isolation (>40 dB) and low return loss (>12 dB at RFC) without external matching. Its pHEMT-based SPDT architecture supports bidirectional RF flow between RFC and either RF1 or RF2, controlled exclusively by two logic-level negative voltages (CTRLA/CTRLB).

Switching is governed by a truth table where High/Low on CTRLA/CTRLB selects RF1↔RFC conduction while terminating RF2 internally to 50 Ω, and vice versa. No supply rail is required-only ground-connected die bottom and controlled negative bias on dedicated control pads.

Key Specifications

Pinout & Package

Package: 10-pad GaAs MMIC bare die (C-10-9), 1.22 mm × 0.85 mm × 0.1 mm, back-metallized for direct ground-plane attachment. Die bottom must be electrically connected to RF ground.

Key Features

Applications

Equivalent & Alternatives

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

Compared with HMC547LP3E and QM11036, the HMC347A uniquely combines supply-free negative-voltage control, 0.1–20 GHz bandwidth, and nonreflective 50 Ω design in a miniature bare die-making it irreplaceable for high-frequency, size-constrained, and supply-limited microwave modules.

Availability

HMC347A is available at Aetrix Electronics and suitable for microwave radio front-ends, military radar TR modules, and broadband test instrumentation requiring stable component supply across extended temperature ranges and high-frequency performance.

Supply support for HMC347A 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 HMC347A belongs to Analog Devices' legacy Hittite Microwave MMIC product line, engineered specifically for broadband microwave switching in defense, aerospace, and test equipment where size, linearity, and frequency agility are critical.

FAQ

What is the operating voltage requirement for the HMC347A?

The HMC347A requires two negative control voltages: −5 V applied to either CTRLA or CTRLB (logic High), and 0 V applied to the complementary control input (logic Low). No positive supply or ground-referenced bias rail is needed-the device draws only microamp-level control current (≤10 µA) and operates entirely from these dual negative logic levels.

Does the HMC347A require external matching components?

No, the HMC347A features a fully nonreflective, 50 Ω matched architecture across 0.1–20 GHz. All RF pads (RFC, RF1, RF2) are dc-coupled and internally matched-eliminating the need for external baluns, transformers, or matching networks. Blocking capacitors are only required if the connected RF line has a nonzero DC potential.

How is thermal management handled for the HMC347A?

The HMC347A die bottom must be directly attached to an RF ground plane using AuSn eutectic preform or conductive epoxy. Its thermal resistance (θJC) is 118 °C/W for the through path and 200 °C/W for the terminated path. Effective heat sinking relies on low-thermal-resistance die attach and proper PCB copper pour beneath the die-no heatsink or thermal vias are integrated into the bare die itself.

Can the HMC347A be used in hot-switching conditions?

Yes, the HMC347A supports hot switching at reduced power levels: 23 dBm maximum for the through path and 17 dBm for the terminated path when using −3 V control voltage, and 23 dBm hot-switching rating at −5 V control. Exceeding these limits risks permanent damage due to localized heating at the internal FET junctions during state transition.

What is the recommended bonding method for the HMC347A RF pads?

Analog Devices specifies 3 mil × 0.5 mil gold ribbon bonds for RF pads (RFC, RF1, RF2) and 1 mil diameter gold wire bonds for control pads (CTRLA, CTRLB). Bond lengths must be minimized (<3 mil nominal gap), and microstrip substrates should be placed as close as possible to the die surface (typical spacing: 0.076 mm) to preserve broadband RF performance and reduce parasitic inductance.