Analog Devices Inc. HMC135

Overview

HMC135 from Analog Devices (formerly Hittite Microwave) is a GaAs MMIC bi-phase modulator die designed for RF phase modulation into 0°/180° states in the 1.8–5.2 GHz band. It functions as a modulator, demodulator, and phase comparator with 30 dB typical carrier suppression, 11 dB typical insertion loss, and 5° typical phase balance. It is used in point-to-point radios and LMDS infrastructure.

For engineers reviewing the HMC135 datasheet, HMC135 pinout, HMC135 application, or HMC135 equivalent, this page delivers verified technical context, validated package and terminal mapping, confirmed functional alternatives, and design-meaningful specifications - all grounded in the official v04.0909 datasheet and Hittite/Analog Devices application documentation.

Technical Context

The HMC135 implements a monolithic balanced diode architecture with integrated baluns to achieve precise amplitude and phase matching between quadrature paths. Its control port (IF) accepts DC bias current (2–10 mA) to steer RF signal polarity at the LO output, enabling direct phase modulation without external hybrids.

As a phase comparator, it generates an analog voltage at the IF port proportional to the phase difference between RF and LO inputs; as a demodulator, it recovers baseband data from modulated RF signals applied to the RF port while referencing a clean LO signal. All RF/LO ports are DC-coupled and 50 Ω matched.

Key Specifications

Pinout & Package

Package: Bare GaAs MMIC die (unpacked), 1.45 × 1.45 × 0.1 mm, gold metallized bond pads, backside grounded, supplied in Waffle Pack (WP-3).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar bi-phase modulator applications.

Compared with HMC135, HMC1045 offers broader bandwidth and higher linearity at the cost of larger size and higher bias current, while QM11023 trades phase-comparator versatility for smaller footprint and integrated biasing - making HMC135 optimal for legacy MIC-based BPSK systems requiring triple-function operation.

Availability

HMC135 is available at Aetrix Electronics and suitable for point-to-point radios, LMDS infrastructure, and RF test equipment requiring stable component supply despite its obsolete status through controlled legacy sourcing.

Supply support for HMC135 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, Inc. is a global semiconductor leader specializing in high-performance analog, mixed-signal, and RF technologies, with deep heritage in microwave ICs via its acquisition of Hittite Microwave.

The HMC135 belongs to Hittite's legacy GaAs MMIC modulator product line, engineered specifically for microwave communication systems demanding high carrier suppression and phase accuracy in compact chip form.

FAQ

What is the primary circuit role of the HMC135 in RF systems?

The HMC135 serves as a bi-phase modulator that converts baseband logic states into 0°/180° phase-shifted RF outputs at the LO port, using DC bias polarity on the IF port. It also functions as a phase comparator-generating analog voltage proportional to RF–LO phase difference-and as a demodulator, recovering data from modulated RF signals. This triple functionality is intrinsic to the HMC135's monolithic GaAs architecture and confirmed in its v04.0909 datasheet.

Can the HMC135 be used without external DC blocking capacitors?

Yes-the HMC135's RF and LO ports are DC-coupled and internally matched to 50 Ω, allowing direct connection to bias tees or active circuits without series DC blocking. However, the IF port must not source or sink more than 10 mA, and for non-DC-coupled IF operation, external series capacitance is required per the datasheet. This DC coupling behavior is explicitly specified for the HMC135 in the "Pad Descriptions" section.

What is the recommended bias current for optimal carrier suppression in the HMC135?

The HMC135 achieves its rated 30 dB typical carrier suppression at a nominal 5 mA DC bias current applied to the IF port, as measured under static conditions per the v04.0909 datasheet. The device operates across 2–10 mA, but deviation from 5 mA reduces suppression-e.g., 2 mA yields ~25 dB, while 10 mA may degrade linearity. This 5 mA value is the design center for the HMC135's specified performance.

How is the HMC135 physically mounted and interconnected in MIC designs?

The HMC135 is a bare die (1.45 × 1.45 × 0.1 mm) with gold bond pads and grounded backside metal. It is mounted eutectically (AuSn) or with conductive epoxy onto a grounded alumina substrate, then wire-bonded using 0.003" ribbon for RF and 0.001" wire for DC. Recommended microstrip thickness is 5 mil; bond wire length must stay under 12 mils. These mounting rules are documented in the HMC135's "Mounting & Bonding Techniques" application note.

Is the HMC135 still in active production, and how does Aetrix support its supply?

No-the HMC135 is marked OBSOLETE by Analog Devices, with last-time-buy status. Aetrix Electronics provides controlled legacy sourcing with traceable waffle-pack inventory, BOM continuity management, and lifecycle coordination. Supply support includes scheduled delivery planning and volume procurement assistance-ensuring continuity for existing deployed systems reliant on the HMC135's specific performance envelope.