STMicroelectronics RF5L15120CB4

Overview

RF5L15120CB4 from STMicroelectronics is a 120 W, 50 V LDMOS RF power transistor optimized for broadband operation from HF to 1.5 GHz, delivering 20 dB gain and 60% drain efficiency at 1000 MHz under pulsed CW conditions with 50 V supply and 100 mA quiescent current. It features dual-gate/dual-drain topology, integrated ESD protection (HBM Class 2), and operates in Class AB/B or C for modulation formats including OFDM and DVB-T.

For engineers reviewing the RF5L15120CB4 datasheet, RF5L15120CB4 pinout, RF5L15120CB4 application, or RF5L15120CB4 equivalent, key selection criteria include its 0.7 °C/W junction-to-case thermal resistance, ±8 V gate-source voltage range, 95 V drain-source breakdown rating, and LBB package suitability for high-power RF amplifier stages in broadcast and avionics transmitters.

Technical Context

This LDMOS FET employs a vertically diffused structure with field-plate-assisted edge termination to sustain 95 V V(BR)DSS and support stable operation up to +200 °C junction temperature. Its low CRSS (0.6 pF) and CISS (56 pF) enable wideband impedance matching across HF–1.5 GHz while maintaining high reverse isolation.

The device integrates symmetrical dual-gate and dual-drain terminals to support push-pull or balanced amplifier configurations without external combiners. Gate threshold voltage (2–2.8 V) and quiescent gate voltage (2–6 V) are specified for precise bias control under varying thermal load, supporting robust linearization in high-PAR signal environments.

Key Specifications

Pinout & Package

The RF5L15120CB4 is housed in the thermally enhanced LBB package: a 29.0 mm × 22.9 mm × 6.6 mm ceramic/metal flanged package with bottom-side source connection and isolated gate/drain terminals. The package features four mounting holes (M3), copper base for direct heatsink attachment, and RoHS-compliant ECOPACK2 finish.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar RF power transistor applications.

Compared with RF5L15120CB3 and PD57018-E, the RF5L15120CB4 uniquely combines dual-gate flexibility, 10:1 VSWR ruggedness, and avionics-qualified thermal stability-making it optimal for mission-critical broadband RF amplifiers where reliability under load mismatch and temperature stress is non-negotiable.

Availability

RF5L15120CB4 is available at Aetrix Electronics and suitable for TV broadcast transmitters, avionics communication systems, and industrial RF heating generators requiring stable component supply across long-lifecycle programs.

Supply support for RF5L15120CB4 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, microcontroller, power, and RF products for automotive, industrial, and communications markets.

The RF5L series targets high-reliability RF power amplification in regulated environments; this LDMOS family emphasizes thermal robustness, ruggedness under VSWR stress, and compliance with aerospace and broadcast emission standards.

FAQ

What is the recommended gate bias voltage for Class AB operation?

For Class AB operation at 100 mA quiescent drain current, the datasheet specifies VGS(Q) = 2–6 V (typical 4 V) with VDD = 50 V. A fixed bias network using 200 Ω metal-film resistors (R1/R2 per test circuit) and bypass capacitors ensures stable gate voltage under RF drive, minimizing thermal runaway risk.

Can RF5L15120CB4 be operated in Class C for FM broadcast?

Yes-the device supports Class C operation with gate bias set below threshold (e.g., VGS = −2 V to −4 V) and is characterized for 120 W pulsed CW output. Its 95 V V(BR)DSS and 10:1 VSWR tolerance make it suitable for FM broadcast finals where high efficiency and load mismatch resilience are critical.

Is the LBB package compatible with standard RF heatsink mounting practices?

Yes-the LBB package uses four M3 mounting holes aligned to industry-standard 25.4 mm pitch, a flat copper base (17.78 mm × 16.51 mm), and 0.7 °C/W thermal resistance. It mounts directly to aluminum or copper heatsinks using thermal interface material (e.g., T-Grease 2000) and torque-controlled screws (0.5–0.7 N·m).

Does RF5L15120CB4 require external ESD protection on the gate pins?

No-this device integrates HBM Class 2 ESD protection (≥2 kV) per JESD22-A114 on all gate terminals. External gate protection diodes are unnecessary in production designs, though proper PCB layout (short traces, ground plane proximity) remains essential to preserve RF performance and ESD robustness.