Analog Devices Inc. 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, featuring 2.3 dB typical insertion loss at 10 GHz, 45 dB isolation at 10 GHz, and integrated 2:4 TTL decoder reducing control lines from four to two. It is used in microwave radio front-ends requiring broadband signal routing with low distortion and fast switching.

For engineers reviewing the HMC641LP4E datasheet, HMC641LP4E pinout, HMC641LP4E application, or HMC641LP4E equivalent, this page delivers verified specifications, package mapping, truth table–based control logic, thermal resistance data (199 °C/W), and real-world use cases in SATCOM, test instrumentation, and military hybrids - all tied explicitly to the HMC641LP4E variant.

Technical Context

The HMC641LP4E implements a monolithic GaAs pHEMT architecture with on-chip 50 Ω terminations for all isolated RF ports, enabling true non-reflective operation across DC–20 GHz. Its integrated binary decoder accepts 0/–5 V logic inputs (CTRLA/CTRLB) to select one of four RF paths (RF1–RF4) from the common RFC port.

Switching is controlled via dual negative-voltage logic with specified bias: Vss = –5 V ±10%, CTRLA/CTRLB swing between –5 V to –3.8 V (high) and –2.5 V to 0 V (low); tRISE/tFALL is 15 ns, and tON/tOFF is 88 ns across full bandwidth. Thermal design requires soldering all ground leads and the exposed paddle to PCB RF ground per MSL1 reflow profile.

Key Specifications

Pinout & Package

Package: 24-lead 4×4 mm plastic SMT package (RoHS-compliant, MSL1, matte Sn finish), with exposed ground paddle requiring connection to PCB RF ground. Thermal resistance is 199 °C/W (insertion path) and 219 °C/W (terminated path).

Key Features

Applications

Equivalent & Alternatives

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

Compared with HMC641LC4 and QM11036, the HMC641LP4E uniquely combines negative-voltage 0/–5 V control, integrated decoder, and plastic-package manufacturability - making it optimal for high-volume microwave radios where control simplicity and SMT yield are critical.

Availability

HMC641LP4E is available at Aetrix Electronics and suitable for telecom infrastructure, microwave radio & VSAT, and test instrumentation requiring stable component supply, consistent MSL1 handling, and RoHS-compliant packaging.

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 maintains its high-frequency RF portfolio, specializing in GaAs, GaN, and SiGe MMICs for defense, aerospace, and communications.

The HMC641LP4E belongs to Hittite's legacy broadband switch family, designed specifically for non-reflective, high-isolation RF path selection in compact SMT form factors - targeting microwave radio, SATCOM, and instrumentation where signal integrity and layout simplicity are paramount.

FAQ

What is the recommended PCB grounding strategy for the HMC641LP4E?

Per the datasheet, all ground leads (pins 2,4,7,9,10,12,17,19,21,22,24) and the exposed ground paddle must be soldered directly to the PCB RF ground plane using multiple thermal vias. This ensures optimal RF return path integrity, thermal dissipation (199 °C/W), and minimizes parasitic inductance that could degrade isolation above 10 GHz. The HMC641LP4E evaluation board (126508) uses Rogers 4350 substrate with 50 Ω microstrip routing.

Does the HMC641LP4E require external DC blocking capacitors on RF ports?

Yes - the HMC641LP4E RFC, RF1, RF2, RF3, and RF4 ports are DC-coupled and matched to 50 Ω, so external blocking capacitors are required whenever the connected RF line has non-zero DC potential. Typical values are 100 pF for DC–6 GHz and 10 pF for 6–20 GHz; capacitor placement must minimize series inductance to preserve high-frequency return loss (>17 dB up to 20 GHz).

How does the integrated 2:4 decoder in the HMC641LP4E reduce system complexity?

The HMC641LP4E's on-die binary decoder translates two 0/–5 V control lines (CTRLA/CTRLB) into four independent SP4T states, eliminating the need for external logic gates or FPGA GPIO expansion. This reduces PCB trace count, routing congestion, and potential timing skew - especially valuable in dense microwave modules where every mm² matters. The decoder operates with <2 µA input current, minimizing drive burden.

What is the maximum RF input power the HMC641LP4E can handle continuously?

The HMC641LP4E has an absolute maximum input power rating of +24 dBm, but continuous operation should stay below the 1 dB compression point: 22 dBm (typical) from 0.25–20 GHz. At +20 dBm input, third-order intermodulation remains suppressed (IP3 = 38 dBm), ensuring clean spectral performance in multi-carrier systems. Thermal derating is required above +85°C ambient.

Can the HMC641LP4E be used with positive logic control voltages?

No - the HMC641LP4E is strictly designed for 0/–5 V negative logic: "High" = –5 V to –3.8 V, "Low" = –2.5 V to 0 V. Applying positive voltages (e.g., 0/+3.3 V) violates absolute maximum ratings and may damage the control circuitry. For positive logic systems, level-shifting circuitry or alternative parts like Qorvo QM11036 must be used instead of direct substitution of the HMC641LP4E.