Analog Devices Inc. 111227-HMC908LC5

Overview

HMC908LC5 from Analog Devices (formerly Hittite Microwave) is a GaAs MMIC I/Q downconverter IC designed for RF front-end signal translation in 9–12 GHz systems. It delivers 11 dB small-signal conversion gain, 2.2 dB noise figure, and 25 dB image rejection with DC–3.5 GHz IF bandwidth, operating from 3 V (VD1/VD2) and 5 V (VD3) supplies. It serves as the core downconversion stage in point-to-point radio and EW receivers.

For engineers reviewing the HMC908LC5 datasheet, HMC908LC5 pinout, HMC908LC5 application, or HMC908LC5 equivalent, key selection criteria include its 9–12 GHz RF band, image-reject architecture requiring external 90° hybrid, LO isolation >40 dB, and 32-lead 5×5 mm ceramic SMT package compatibility with RF PCB grounding best practices.

Technical Context

The HMC908LC5 integrates an LNA followed by an image-reject mixer driven by an on-chip LO buffer amplifier, eliminating post-LNA filtering and suppressing thermal noise at the image frequency. Its quadrature outputs (IF1/IF2) require external 90° hybrid to select upper or lower sideband.

It operates across three distinct supply domains: VD1/VD2 = 3 V powers the RF LNA stage (ID1 + ID2 = 60–88 mA), while VD3 = 5 V powers the LO amplifier (ID3 = 100–120 mA). All RF/LO/IF ports are impedance-matched to 50 Ω, with AC-coupled RF and LO inputs and DC-coupled IF outputs.

Key Specifications

Pinout & Package

32-lead 5×5 mm ceramic SMT package with exposed ground paddle; alumina body, gold-plated leads, MSL3 rating, max reflow 260 °C. All ground pins (2, 4, 10, 12, 17, 19, 21) and ground paddle must be soldered to RF/DC ground per layout guidelines.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar I/Q downconverter applications.

Compared with HMC1048LC5 and ADL5380ACPZ-R7, the HMC908LC5 offers optimized X-band performance with highest conversion gain and lowest noise figure in its class, making it preferred for fixed-frequency, high-sensitivity 9–12 GHz receivers where size and thermal efficiency are constrained.

Availability

HMC908LC5 is available at Aetrix Electronics and suitable for point-to-point radio, military radar receivers, and satellite communications terminals requiring stable component supply and RoHS-compliant ceramic SMT packaging.

Supply support for HMC908LC5 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 microwave and millimeter-wave components for defense, aerospace, and communications.

The HMC908LC5 belongs to Hittite's legacy GaAs MMIC I/Q downconverter product line, engineered specifically for compact, high-performance X-band receiver front ends in space-constrained military and SATCOM platforms.

FAQ

What is the recommended LO drive level for optimal performance of the HMC908LC5?

The HMC908LC5 achieves best conversion gain, noise figure, and image rejection at 0 dBm LO drive. Performance degrades outside −2 dBm to +4 dBm range; LO overdrive above +4 dBm risks compression and increased distortion. The HMC908LC5 datasheet specifies 0 dBm as the nominal condition for all typical specifications including the 11 dB gain and 2.2 dB noise figure.

Does the HMC908LC5 require an external 90° hybrid, and why?

Yes, the HMC908LC5 requires an external 90° hybrid to combine its IF1 and IF2 outputs and select either upper or lower sideband. The device itself provides true quadrature outputs but lacks internal hybrid functionality. This architecture allows designers to choose hybrid type (lumped, stripline, or active) based on IF frequency and loss budget - a flexibility confirmed in the HMC908LC5 functional diagram and typical application schematic.

Can the HMC908LC5 operate with DC-coupled IF outputs, and what are the limits?

Yes, the HMC908LC5 IF1 and IF2 pins are DC-coupled and support true baseband operation. However, each IF output must not sink or source more than ±3 mA DC current to prevent malfunction or permanent damage. This limit is explicitly stated in the HMC908LC5 pin descriptions and applies regardless of whether the IF path is used for DC or AC signals.

What is the absolute maximum RF input power for the HMC908LC5?

The absolute maximum RF input power for the HMC908LC5 is +5 dBm, as defined in the Absolute Maximum Ratings table. Exceeding this level risks irreversible damage to the GaAs MMIC front-end, especially the LNA stage. For reliable operation, the 1 dB compression point is specified at −5 dBm input, meaning linear operation is guaranteed only below that level.

How should the ground paddle and N/C pins be handled in the PCB layout for the HMC908LC5?

All ground pins (2, 4, 10, 12, 17, 19, 21) and the exposed ground paddle must be soldered directly to a solid RF/DC ground plane using multiple low-inductance vias. The N/C pins (1, 5, 7–9, etc.) are internally unconnected but must also be externally grounded per measurement conditions - this requirement is documented in the HMC908LC5 pin descriptions and ensures consistent RF performance and thermal stability.