Analog Devices Inc. HMC347C8TR

Overview

HMC347C8TR from Analog Devices (formerly Hittite Microwave) is a GaAs MMIC SPDT switch in a non-hermetic surface-mount ceramic package, designed for RF signal routing in DC–8 GHz systems. It delivers >50 dB isolation up to 2 GHz, 2.0 dB typical insertion loss, and operates with -5/0 V complementary logic control without bias supply. It serves as a high-isolation replacement for HMC132C8 in microwave transceivers and test instrumentation.

For engineers reviewing the HMC347C8TR datasheet, HMC347C8TR pinout, HMC347C8TR application, or HMC347C8TR equivalent, key selection criteria include isolation vs. frequency, non-reflective architecture, thermal resistance (440 °C/W on insertion path), RF power handling (+27 dBm absolute max), and compatibility with 50 Ω RF layouts requiring grounded paddle soldering.

Technical Context

The HMC347C8TR implements a non-reflective GaAs MESFET topology with two independent RF paths (RFC→RF1 and RFC→RF2), controlled by complementary negative-voltage logic (CTLA/CTLB). Its design eliminates external bias networks and enables fast switching (tRISE/tFALL = 3 ns, tON/tOFF = 6 ns) across DC–8 GHz.

It features matched 50 Ω DC-coupled RF ports (RFC, RF1, RF2), requires PCB ground connection via all GND pins (2,3,8) and the exposed paddle, and mandates blocking capacitors when RF line DC potential ≠ 0 V. Thermal management relies on direct soldering of the copper-bottom package to RF ground plane.

Key Specifications

Pinout & Package

Package: 8-lead non-hermetic ceramic SMT (white alumina body, copper bottom, electrolytic gold plating); dimensions per outline drawing - length/width exclude lid seal protrusion (0.005″/side); ground leads and paddle must be soldered to PCB RF ground.

Key Features

Applications

Equivalent & Alternatives

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

Compared with HMC132C8TR and QM11036, the HMC347C8TR provides superior isolation above 2 GHz, true DC–8 GHz bandwidth, and non-reflective operation - making it the only option among the three qualified for precision microwave test and military ECM systems requiring broadband, high-linearity, and thermally stable switching.

Availability

HMC347C8TR is available at Aetrix Electronics and suitable for telecom infrastructure, microwave radio & VSAT, and test instrumentation requiring stable component supply, full traceability, and long-term lifecycle support.

Supply support for HMC347C8TR 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 integrates its high-frequency RF portfolio into ADI's broader signal chain solutions. The company specializes in precision analog, RF, and mixed-signal semiconductors.

The HMC347C8TR belongs to Hittite's legacy GaAs MMIC SPDT switch family, engineered specifically for high-isolation, broadband RF routing in defense, aerospace, and instrumentation applications where thermal stability and non-reflective behavior are critical.

FAQ

What is the maximum RF input power rating for the HMC347C8TR?

The HMC347C8TR has an absolute maximum RF input power rating of +27 dBm when control voltage is set to -5 V. However, caution is advised against "hot switching" above +13 dBm under standard -5/0 V control conditions. Derating is required above +23 dBm to maintain reliability, as confirmed by the 19–23 dBm P1dB range and 440 °C/W thermal resistance specification. Always refer to the absolute maximum ratings table in the official HMC347C8TR datasheet for safe operating limits.

Does the HMC347C8TR require external bias components?

No, the HMC347C8TR requires no external bias supply or passive components for basic operation. It functions using only complementary -5 V / 0 V control voltages applied to CTLA and CTLB pins. The internal GaAs MESFET architecture eliminates the need for bias resistors, decoupling capacitors, or level shifters - simplifying layout and reducing bill-of-materials cost compared to many competing SPDT switches.

How is the HMC347C8TR's non-reflective design implemented?

The HMC347C8TR implements non-reflective behavior by terminating the off-state RF port (e.g., RF2 when RFC→RF1 is active) into a matched 50 Ω load internally. This prevents signal reflections that would otherwise degrade VSWR and cause instability in cascaded stages. Measured return loss in the off-state reaches 9 dB at DC–2 GHz, confirming effective termination - a key advantage over reflective SPDT switches in sensitive receiver front-ends.

What is the recommended PCB grounding method for the HMC347C8TR?

The HMC347C8TR requires soldering all GND pins (2, 3, 8) and the exposed copper paddle on the package bottom directly to the PCB's RF ground plane. This dual-path grounding minimizes inductance and ensures optimal thermal dissipation (440 °C/W) and RF shielding. Failure to connect the paddle results in degraded isolation, increased insertion loss, and potential thermal runaway under high-power operation.

Can the HMC347C8TR be used in DC-coupled applications?

Yes, the HMC347C8TR supports true DC-coupled operation on all RF ports (RFC, RF1, RF2), enabling baseband and low-frequency IF signal routing. However, blocking capacitors must be added if the DC potential on any RF line differs from 0 V - as stated in the Pin Descriptions section. This capability distinguishes it from AC-coupled alternatives and makes it suitable for I/Q modulator/demodulator interfaces and calibration loopbacks.