Analog Devices Inc. 119197-HMC656LP2

Overview

HMC656LP2 from Analog Devices (formerly Hittite Microwave) is a 10 dB wideband fixed attenuator IC for RF signal conditioning in 50 Ω systems, operating from DC to 25 GHz with ±1.5 dB attenuation tolerance, 7 dB min return loss, and +25 dBm CW power handling - used in fiber optic transceivers and microwave radio front-ends.

For engineers reviewing the HMC656LP2 datasheet, HMC656LP2 pinout, HMC656LP2 application, or HMC656LP2 equivalent, key selection criteria include broadband flatness (DC–25 GHz), RoHS-compliant 2×2 mm SMT package, 6-pin ground-signal-ground layout, and compatibility with high-volume RF PCB assembly requiring controlled impedance and direct ground paddle soldering.

Technical Context

This passive 50 Ω matched attenuator uses low-stress injection-molded plastic packaging with 100% matte tin lead finish (MSL1, 260 °C peak reflow) and requires all ground leads and exposed paddle to be soldered directly to PCB RF ground per Hittite's land pattern guidance.

It features DC-coupled RF ports (pins 2 and 5), operates over –40 °C to +85 °C, exhibits 0.0004 dB/°C temperature coefficient, and maintains stable attenuation across frequency without internal bias or control lines - functioning purely as a passive, bidirectional, impedance-matched signal reduction element.

Key Specifications

Pinout & Package

6-lead 2×2 mm SMT package with exposed ground paddle; RoHS-compliant, matte Sn finish, MSL1 rating (260 °C peak reflow). Requires full ground paddle soldering to PCB RF ground plane per Hittite Application Note land pattern guidance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with QAT-10W1000+ and VAT-10W2+, the HMC656LP2 offers superior 25 GHz bandwidth and 2×2 mm footprint but trades off absolute attenuation accuracy and maximum power rating - making it optimal for Ka-band test fixtures and space-constrained microwave radios where flatness to 25 GHz is mandatory.

Availability

HMC656LP2 is available at Aetrix Electronics and suitable for fiber optics, microwave radio, and military radar applications requiring stable component supply, consistent RF performance, and RoHS-compliant manufacturing support.

Supply support for HMC656LP2 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 signal chain solutions for communications, defense, and instrumentation markets.

The HMC656LP2 belongs to the HMC656LP2E–HMC658LP2E wideband fixed attenuator family, engineered specifically for DC–25 GHz applications demanding flat attenuation, low VSWR, and robust surface-mount manufacturability in military, test equipment, and scientific instruments.

FAQ

What is the exact attenuation value and tolerance of the HMC656LP2?

The HMC656LP2 provides a nominal 10 dB attenuation with a tolerance of ±1.5 dB across its full DC–25 GHz operating range and over the –40 °C to +85 °C temperature span. This specification is verified per the official Analog Devices datasheet v02.0112 and applies to both room-temperature and extended-temperature conditions without derating. The HMC656LP2 achieves this stability via monolithic thin-film resistor design and matched 50 Ω terminations.

Does the HMC656LP2 require DC blocking capacitors in circuit?

The HMC656LP2 features DC-coupled RF ports (pins 2 and 5), so external DC blocking capacitors are only required if the connected source or load presents non-zero DC potential that could disrupt bias points. When interfacing with AC-coupled stages or biased amplifiers, designers must add series capacitors; however, the HMC656LP2 itself imposes no DC path limitation and functions correctly with or without DC offset present.

What is the correct PCB land pattern and grounding requirement for the HMC656LP2?

Hittite's Application Note specifies that all four ground pins (1, 3, 4, 6) and the exposed ground paddle must be soldered directly to a solid RF ground plane using a thermally robust layout. The recommended land pattern uses thermal vias under the paddle and symmetric 50 Ω microstrip transitions. Failure to fully ground the paddle degrades return loss and power handling - a critical requirement explicitly called out in the HMC656LP2 datasheet and confirmed in evaluation board 119197 documentation.

Is the HMC656LP2 suitable for Ka-band (26.5–40 GHz) applications?

The HMC656LP2 is characterized and guaranteed from DC to 25 GHz only. While some measured performance may extend marginally beyond 25 GHz, Analog Devices does not specify or guarantee attenuation flatness, return loss, or power handling above 25 GHz. For Ka-band applications requiring validated performance, designers should select components explicitly rated to 40 GHz - the HMC656LP2 remains appropriate for Q-band (33–50 GHz) prototyping only if empirical validation is performed per application, not as a production solution.

What is the ESD sensitivity classification and handling guidance for the HMC656LP2?

The HMC656LP2 is classified as Class 1B per HBM (Human Body Model), meaning it withstands up to 250 V ESD stress. Per datasheet warnings, it is an electrostatic-sensitive device requiring grounded workstations, wrist straps, and static-dissipative packaging. This classification is consistent across the HMC656LP2E–HMC658LP2E family and reflects its thin-film resistor construction - improper handling can permanently alter attenuation accuracy or cause open-circuit failure, especially at the fine-pitch ground paddle interface.