Analog Devices Inc. 126511-HMC641LP4E

Overview

HMC641LP4E from Analog Devices (formerly Hittite Microwave) is a GaAs pHEMT SP4T non-reflective RF switch IC operating from DC to 20 GHz, delivering 2.3 dB typical insertion loss and 45 dB isolation at 10 GHz, with integrated 2:4 TTL decoder and 0/−5 V logic control for telecom infrastructure and test instrumentation signal routing.

For engineers reviewing the HMC641LP4E datasheet, HMC641LP4E pinout, HMC641LP4E application, or HMC641LP4E equivalent, this page provides verified broadband RF switch specifications, truth-table–driven control behavior, thermal resistance data (199 °C/W), RoHS-compliant 24-lead 4×4 mm SMT package details, and real-world use context for microwave radio and SATCOM front-end design.

Technical Context

The HMC641LP4E implements a monolithic GaAs pHEMT architecture with on-chip 50 Ω terminations on all isolated RF ports, enabling non-reflective switching across DC–20 GHz without external termination components. Its integrated binary decoder reduces control lines from four to two (CTRLA/CTRLB), supporting TTL/CMOS-compatible −5 V to 0 V logic thresholds.

It operates with Vss = −5 V ±10%, draws only 1.7 mA typical supply current, and achieves 15 ns rise/fall time and 88 ns turn-on/off delay. Thermal design requires soldering all ground leads and the exposed paddle to PCB RF ground, with channel-to-paddle thermal resistance of 199 °C/W on the insertion path.

Key Specifications

Pinout & Package

Package: 24-lead, RoHS-compliant low-stress injection-molded plastic QFN (4×4 mm body, 0.85 mm height), MSL1 rated, with exposed copper ground paddle requiring solder connection to PCB RF ground plane.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar SP4T RF switch applications.

Compared with HMC641LP4E, HMC641LP4ETR offers identical RF performance in tape format for manufacturing scalability, while QM11036 extends bandwidth by 2 GHz but increases bill-of-materials count and layout risk due to missing on-die terminations.

Availability

HMC641LP4E is available at Aetrix Electronics and suitable for telecom infrastructure, microwave radio & VSAT, and test instrumentation applications requiring stable component supply, full traceability, and long-term lifecycle support.

Supply support for HMC641LP4E 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 MMIC portfolio into precision RF signal chain solutions.

The HMC641LP4E belongs to Hittite's broadband GaAs pHEMT switch product line, engineered specifically for high-isolation, low-loss RF path selection in microwave communications and instrumentation where non-reflective behavior and minimal control overhead are critical.

FAQ

What is the operating temperature range for the HMC641LP4E?

The HMC641LP4E is specified for operation from −40 °C to +85 °C ambient temperature. Its thermal resistance of 199 °C/W on the insertion-loss path requires proper PCB grounding of the exposed paddle and surrounding ground leads to maintain junction temperature below 150 °C under maximum RF power conditions. This range supports deployment in outdoor telecom cabinets and field-deployable test gear.

Does the HMC641LP4E require external termination resistors?

No, the HMC641LP4E does not require external termination resistors. It features on-chip 50 Ω terminations for all isolated RF ports (RF1–RF4) in the off state, enabling true non-reflective switching. This eliminates the need for discrete surface-mount resistors and associated PCB layout area, simplifying design and improving broadband return loss stability across DC–20 GHz.

What logic voltage levels are compatible with HMC641LP4E control inputs?

The HMC641LP4E accepts TTL/CMOS-compatible control voltages on CTRLA and CTRLB: "Low" = −2.5 V to 0 V (30 µA typical sink), "High" = −5 V to −3.8 V (1.7 µA typical sink). It is designed for direct interface with −5 V logic families or level-shifted 0/3.3 V systems using simple resistor networks - no active level translators needed.

How many RF ports does the HMC641LP4E have, and what is their configuration?

The HMC641LP4E is an SP4T (Single-Pole, Four-Throw) switch with one common RF port (RFC) and four selectable output ports (RF1, RF2, RF3, RF4). All RF ports are DC-coupled and 50 Ω matched. The device routes RFC to exactly one of RF1–RF4 based on the two-bit CTRLA/CTRLB state per the documented truth table, with all unselected ports internally terminated.

Is the HMC641LP4E pin-compatible with any other Analog Devices or Hittite switches?

The HMC641LP4E is not pin-compatible with other Hittite/Analog Devices SP4T switches such as the HMC244 or HMC547 series - those use different packages, pin counts, and biasing schemes. Its 24-lead 4×4 mm QFN footprint and specific pin assignments (e.g., Vss on Pin 14, CTRLA on Pin 16) are unique to this part. Migration requires PCB redesign and layout validation.