Analog Devices Inc. HMC424LP3E

Overview

HMC424LP3E from Analog Devices (formerly Hittite Microwave) is a GaAs MMIC 6-bit digital attenuator IC operating from DC to 13 GHz, featuring 0.5 dB LSB steps up to 31.5 dB total attenuation, ±0.5 dB typical bit error, 3.8 dB typical insertion loss at 4 GHz, and +32 dBm IIP3 in attenuated states - deployed in microwave radios and fiber-optic transceivers.

For engineers reviewing the HMC424LP3E datasheet, HMC424LP3E pinout, HMC424LP3E application, or HMC424LP3E equivalent, key selection criteria include broadband DC–13 GHz operation, RoHS-compliant 9 mm² leadless SMT package, single -5 V bias requirement, 6-bit parallel TTL-compatible control interface, and verified performance across -55°C to +85°C industrial temperature range.

Technical Context

The HMC424LP3E implements a monolithic GaAs-based 6-bit switched-attenuator architecture with binary-weighted resistive networks (0.5/1/2/4/8/16 dB bits), DC-coupled 50 Ω RF ports requiring external blocking capacitors, and six independent CMOS/TTL-compatible control inputs toggled between 0 V and -5 V.

It operates with a single negative supply (Vee = -5 V ±10%), draws ≤5 mA total bias current, achieves <50 ns switching time (tON/tOFF), maintains ≥12 dB return loss across DC–13 GHz in all attenuation states, and delivers stable attenuation accuracy referenced to insertion loss with ±(0.3 + 3% of setting) max error for low-range states.

Key Specifications

Pinout & Package

Package: 16-lead 3×3 mm leadless plastic QFN (RoHS-compliant matte Sn finish, MSL1, exposed paddle grounded).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar digital RF attenuator applications.

Compared with HMC424LP3E, HMC624LP4E extends frequency range and resolution at the cost of higher insertion loss, while PE43711 trades broadband performance for integrated serial interface and lower supply voltage - making HMC424LP3E optimal for DC–13 GHz, high-accuracy, industrial-temperature analog-controlled systems.

Availability

HMC424LP3E is available at Aetrix Electronics and suitable for basestation infrastructure, fiber-optic transceivers, and microwave radio systems requiring stable component supply, full RoHS compliance, and guaranteed long-term availability.

Supply support for HMC424LP3E 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/Microwave portfolio into precision signal processing solutions.

The HMC424LP3E belongs to Hittite's legacy GaAs MMIC digital attenuator product line, engineered specifically for broadband RF power control in demanding wireless infrastructure and defense applications.

FAQ

What is the absolute maximum RF input power rating for the HMC424LP3E?

The HMC424LP3E has an absolute maximum RF input power rating of +25 dBm across 0.5–13 GHz, as specified in the Absolute Maximum Ratings table. Operation above this level risks permanent damage to the GaAs MMIC die. For reliable linear operation, the datasheet recommends limiting input power to +22 dBm (0.1 dB compression point) - a design margin that preserves attenuation accuracy and intermodulation performance in the HMC424LP3E.

Does the HMC424LP3E require external blocking capacitors on its RF ports?

Yes, the HMC424LP3E requires external DC-blocking capacitors on both RFIN (Pin 2) and RFOUT (Pin 11) because its RF ports are DC-coupled and internally biased. If the connected circuitry applies any DC voltage other than 0 V to these lines, signal integrity degrades and potential damage may occur. The datasheet specifies use of 0.01 µF capacitors in 0603 package - a value selected to maintain impedance match and phase response across DC–13 GHz in the HMC424LP3E.

What is the recommended PCB grounding strategy for the HMC424LP3E's exposed paddle?

The HMC424LP3E's exposed metal paddle must be soldered directly to the PCB's RF ground plane using multiple thermal vias (≥6 recommended) to ensure low-inductance grounding and effective heat dissipation. Hittite's application note specifies that all ground leads (Pins 1, 3, 10, 12) and the paddle must connect to the same solid ground plane - failure to do so increases insertion loss variation and degrades return loss below 12 dB in the HMC424LP3E.

Can the HMC424LP3E operate with control voltages referenced to ground instead of Vee?

No - the HMC424LP3E control inputs (V1–V6) are designed for negative logic: logic-low is 0 to -3 V (relative to ground), and logic-high is Vee to Vee+0.8 V (i.e., -5 V to -4.2 V). Driving them with ground-referenced 0/+3.3 V signals will cause undefined behavior or latch-up. A level-shifting driver circuit (e.g., using 74LVC1G04 inverters with -5 V supply) is required to interface standard logic to the HMC424LP3E.

Is the HMC424LP3E pin-compatible with the non-RoHS HMC424LP3 variant?

Yes, the HMC424LP3E is mechanically and electrically pin-compatible with the HMC424LP3 - both share identical 16-lead 3×3 mm QFN outline, pin numbering, function mapping, and electrical specifications. The only differences are RoHS compliance (matte Sn vs. Sn/Pb finish), higher reflow temperature tolerance (260 °C vs. 235 °C), and MSL1 rating - all preserved in the HMC424LP3E without altering PCB layout or firmware.