Analog Devices Inc. 109266-HMC550A

Overview

HMC550A from Analog Devices (formerly Hittite Microwave) is a GaAs MMIC SPST failsafe RF switch designed for DC–6 GHz signal routing in battery-powered and low-power RF systems. It features 0.7 dB typical insertion loss, +52 dBm input IP3, 200 nA on-state current, failsafe "on" operation when unpowered, and operates from 1.2–5 V supply voltage.

For engineers reviewing the HMC550A datasheet, HMC550A pinout, HMC550A application, or HMC550A equivalent, this device is selected for ultra-low-current RF switching in RFID tags, ISM-band portables, automotive telematics, and WiMAX front-ends where power-off state integrity and wideband linearity are critical.

Technical Context

The HMC550A implements a monolithic GaAs pHEMT-based SPST topology with failsafe biasing: RF1–RF2 path remains conductive (low-loss) when Vdd and Vctl are unapplied. Its control logic accepts CMOS-compatible voltage levels (Vctl = 0/+3.3 V), and it requires no external bias network beyond DC blocking capacitors at both RF ports.

Thermal design relies on its SOT26 package's 180.5 °C/W junction-to-ambient thermal resistance and mandatory RF ground connection via pins 2 and 5. Absolute maximum ratings include +34 dBm RF input power and –40 °C to +85 °C operating temperature, supporting ruggedized portable and automotive deployments.

Key Specifications

Pinout & Package

Package: 6-lead SOT26 plastic package with exposed paddle; RoHS-compliant version (HMC550AE) uses 100% matte Sn finish; MSL1 rating; requires soldering all ground leads (pins 2 and 5) directly to PCB RF ground plane.

Key Features

Applications

Equivalent & Alternatives

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

Compared with QM11036 and SKY13350-374LF, the HMC550A uniquely balances ultra-low quiescent current, failsafe default-on behavior, and DC–6 GHz performance - making it irreplaceable in energy-harvested RFID and safety-critical telematics where power loss must not break RF continuity.

Availability

HMC550A is available at Aetrix Electronics and suitable for RFID tag manufacturing, automotive telematics module assembly, and portable WiMAX/WiBro handset production requiring stable component supply across multi-year product lifecycles.

Supply support for HMC550A 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 precision analog and RF solutions for communications, defense, and instrumentation markets.

The HMC550A belongs to Hittite's legacy GaAs MMIC SPST switch family, engineered specifically for ultra-low-power, failsafe RF signal routing in portable, battery-constrained, and mission-critical wireless systems.

FAQ

What is the failsafe behavior of the HMC550A?

The HMC550A defaults to the "ON" state (low insertion loss between RF1 and RF2) when Vdd and Vctl are unpowered. This failsafe operation ensures RF continuity during power loss, system reset, or standby - critical for GPS fallback in automotive telematics and reliable link maintenance in RFID readers. The HMC550A achieves this via internal GaAs pHEMT biasing that conducts without external voltage.

Does the HMC550A require external DC blocking capacitors?

Yes - the HMC550A requires external DC blocking capacitors at both RF1 and RF2 ports because its RF pins are DC-coupled and internally matched to 50 Ω. Capacitor value determines the lowest usable frequency; for DC–6 GHz operation, typical values range from 100 pF to 1000 pF depending on PCB layout and low-frequency cutoff requirements. The HMC550A evaluation board (109266) uses 100 pF and 1000 pF components.

What is the maximum RF input power the HMC550A can handle?

The HMC550A has an absolute maximum RF input power rating of +34 dBm (2.5 W) under specified Vctl = 0/+3.3 V conditions. This rating applies across its full DC–6 GHz range and enables robust operation in handheld test equipment and burst-mode transmitters. Exceeding +34 dBm risks permanent damage due to channel temperature exceeding 150 °C, even with proper grounding.

How does the HMC550A compare to the HMC550AE variant?

The HMC550AE is the RoHS-compliant version of the HMC550A, using 100% matte tin lead finish (vs. Sn/Pb on HMC550A) and rated for peak reflow up to 260 °C (vs. 235 °C). Electrically and functionally identical, both share the same SOT26 package, pinout, and specifications. The HMC550A remains viable for legacy non-RoHS production, while HMC550AE is required for modern environmental compliance mandates.

Can the HMC550A operate from a 1.8 V supply?

Yes - the HMC550A supports Vdd from 1.2 V to 5.0 V, including 1.8 V operation. At 1.8 V, it maintains failsafe "ON" behavior and delivers <1.0 dB insertion loss up to 3 GHz. However, IP3 degrades slightly (~+49 dBm), and isolation drops to ~18 dB at 2 GHz. System validation at 1.8 V is recommended for battery-powered IoT nodes where voltage scaling is used to extend runtime.