Analog Devices Inc. 115857-HMC633LC4

Overview

HMC633LC4 from Analog Devices (formerly Hittite Microwave) is a GaAs PHEMT MMIC driver amplifier operating from 5.5 to 17 GHz, delivering 30 dB gain, +23 dBm P1dB, and +30 dBm output IP3 at 180 mA from a +5 V supply. It features DC-blocked, 50 Ω matched I/Os in a leadless 4×4 mm ceramic SMT package and serves as a broadband LO driver or RF stage in microwave radio transceivers.

For engineers reviewing the HMC633LC4 datasheet, HMC633LC4 pinout, HMC633LC4 application, or HMC633LC4 equivalent, this amplifier's temperature-stable gain (±0.04 dB/°C), low noise figure (7 dB typ.), and bias flexibility (Vgg adjustable from –2 to 0 V) support high-linearity, wideband system design in point-to-point radios and military communications.

Technical Context

The HMC633LC4 employs a monolithic GaAs PHEMT architecture with four independent drain supply pins (Vdd1–Vdd4) and a single gate control pin (Vgg) for precise bias tuning. Its internal matching eliminates external components across 5.5–17 GHz, enabling direct integration into 50 Ω RF signal paths without impedance transformation.

It operates over –40 °C to +85 °C with thermal resistance of 90.23 °C/W (channel to package bottom), requiring soldering of all ground leads and the exposed paddle to PCB RF ground per MSL3 reflow guidelines. Reverse isolation exceeds –20 dB across band, supporting stable cascaded amplifier configurations.

Key Specifications

Pinout & Package

Package: 24-lead leadless ceramic surface-mount package (4×4 mm, 16 mm²), alumina body with gold-over-nickel plating, MSL3 rated, with exposed ground paddle requiring solder connection to PCB RF ground.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar RF driver amplifier applications.

Compared with QPL9057 and PSA-2043+, the HMC633LC4 uniquely covers 5.5–17 GHz with 30 dB gain and MSL3-compliant ceramic packaging - making it the only option among the three qualified for Ku-band VSAT and military airborne RF front-ends requiring wide instantaneous bandwidth and thermal robustness.

Availability

HMC633LC4 is available at Aetrix Electronics and suitable for point-to-point radios, LO driver circuits, and military communications systems requiring stable component supply across extended temperature ranges and high-volume production cycles.

Supply support for HMC633LC4 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 analog and RF solutions for defense, aerospace, and communications.

The HMC633LC4 belongs to Hittite's MMIC driver amplifier product line, engineered specifically for broadband microwave radio transceivers demanding high linearity, wide bandwidth, and repeatable SMT integration.

FAQ

What is the recommended gate bias voltage range for the HMC633LC4?

The HMC633LC4 requires gate bias voltage (Vgg) between –2 V and 0 V to achieve nominal 180 mA supply current. Adjusting Vgg within this range allows trade-offs between gain and power-added efficiency: more negative Vgg reduces current and gain but improves PAE. The datasheet specifies –0.7 V as typical for 180 mA operation, and external bias circuitry must follow Hittite's MMIC Amplifier Biasing Procedure to avoid instability or damage. Always verify Vgg with calibrated instrumentation during prototype validation of the HMC633LC4.

Does the HMC633LC4 require external matching components at RF ports?

No, the HMC633LC4 has internally matched 50 Ω input and output impedances with integrated DC blocking capacitors - no external matching networks, baluns, or DC blocks are needed for standard operation across 5.5–17 GHz. This simplifies PCB layout and improves repeatability in high-frequency designs. However, the application circuit does specify external bypass capacitors (100 pF, 1000 pF, and 2.2 µF) on Vdd and Vgg lines to suppress supply noise and ensure stability. These are decoupling elements, not impedance-matching components, and are mandatory per the HMC633LC4 reference design.

What is the maximum allowable RF input power for the HMC633LC4?

The absolute maximum RF input power for the HMC633LC4 is +5 dBm when Vdd = +5 Vdc, as specified in the Absolute Maximum Ratings table. Exceeding this level risks permanent damage to the GaAs PHEMT transistors due to gate leakage or thermal runaway. In normal operation, input power should remain below –10 dBm to maintain linear amplification and avoid compression or distortion. For high-input scenarios, an external attenuator or limiter is required upstream of the HMC633LC4 to protect the device while preserving system-level dynamic range.

How is thermal management handled for the HMC633LC4 in high-power operation?

The HMC633LC4 dissipates up to 0.99 W continuously at 85 °C ambient, with thermal resistance of 90.23 °C/W (channel to package bottom). Effective thermal management requires soldering all ground leads and the exposed paddle directly to a multilayer PCB's internal ground plane using ≥8 thermal vias (0.3 mm diameter, spaced ≤1 mm apart). For sustained operation above 70 °C ambient, mounting the PCB on an aluminum heatsink with thermal interface material is recommended. The HMC633LC4 evaluation board (115855) uses Rogers 4350 substrate and is designed for such thermal loads - refer to its layout for best practices in RF and thermal co-design.

Is the HMC633LC4 pin-compatible with other Hittite driver amplifiers like the HMC634LC4?

No, the HMC633LC4 is not pin-compatible with the HMC634LC4 or other members of the HMC63xLC4 family. Although both share the same 4×4 mm ceramic package footprint, the HMC634LC4 has different pin assignments - notably, its RFIN and RFOUT are on pins 1 and 24 respectively, whereas the HMC633LC4 places RFIN on pin 3 and RFOUT on pin 16. Additionally, Vdd distribution differs across variants. Substituting without layout revision will cause functional failure. Always consult the specific pinout diagram for each part; the HMC633LC4 pin configuration is validated only for its own application circuit and evaluation board (115855).