STMicroelectronics RF3L05250CB4

Overview

RF3L05250CB4 from STMicroelectronics is a 250 W, 28/32 V LDMOS RF power transistor optimized for HF–1 GHz wideband amplification in class AB/B/C operation. It delivers 18 dB gain and 62% drain efficiency at 650 MHz with 250 W output power under 2.5 dB compression, supporting modulation formats including AM, FM, and SSB in high-power RF transmitters.

For engineers reviewing the RF3L05250CB4 datasheet, RF3L05250CB4 pinout, RF3L05250CB4 application, or RF3L05250CB4 equivalent, key selection criteria include its 90 V V_DS, ±8 to +10 V V_GS range, 0.32 °C/W R_thJC, ESD Class HBM-2/CDM-C3 rating, and LBB package thermal performance for ruggedized HF–UHF amplifier stages.

Technical Context

This LDMOS FET operates across 2–1000 MHz with validated performance at 650 MHz, supporting both linear (class AB) and high-efficiency saturated (class C) modes. Its gate threshold voltage of 1.75–2.50 V and quiescent gate voltage of 3.0 V enable stable biasing for broadband RF power stages.

The device integrates ESD protection per ANSI/ESDA/JEDEC JS001-2017 (HBM Class 2) and JS002-2014 (CDM Class C3), and features a large gate-source voltage swing (−8 V to +10 V) to sustain robust class C operation under dynamic load mismatch up to VSWR 10:1.

Key Specifications

Pinout & Package

The RF3L05250CB4 uses the thermally enhanced LBB (Leadless Bottom-Bonded) package - a 5-terminal surface-mount ceramic/metal hybrid with bottom-side source connection and exposed thermal pad for direct heatsink mounting. Dimensions: 28.95 mm × 22.86 mm × 6.60 mm (L × W × H).

Key Features

Applications

Equivalent & Alternatives

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

Compared with RF3L05250CB3 and MRFE6VP6300HR5, the RF3L05250CB4 offers the best balance of 28 V compatibility, 62% efficiency at 650 MHz, and proven HF–VHF reliability-making it optimal for cost-sensitive, thermally constrained avionics and land-mobile systems.

Availability

RF3L05250CB4 is available at Aetrix Electronics and suitable for HF shortwave transmitters, avionics VHF communication systems, and commercial land mobile radio base stations requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.

Supply support for RF3L05250CB4 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 solutions for industrial, automotive, and communications markets.

The RF3L series targets high-reliability RF power amplification in HF–UHF bands, with design emphasis on thermal robustness, ESD resilience, and class AB/C flexibility for mission-critical communication infrastructure.

FAQ

What is the maximum safe DC supply voltage for continuous operation?

The absolute maximum V_DD is 36 V per datasheet Table 1, but continuous operation at 28 V is recommended for rated 250 W output. Operation at 32 V is permitted only under strict thermal monitoring and derated output power to maintain T_J ≤ 200 °C, as confirmed by thermal simulation using R_thJC = 0.32 °C/W and case temperature ≤ 85 °C.

Does the LBB package require solder paste stencil optimization for the bottom-side source pad?

Yes. The exposed source pad (Pin 3) requires a 70–80% area coverage stencil aperture with 0.15 mm thickness to ensure void-free solder joint formation. ST recommends Type 4 or Type 5 solder paste and reflow profile with peak temperature ≥ 235 °C for reliable thermal interface and mechanical adhesion to the PCB copper plane.

Can RF3L05250CB4 operate reliably under 10:1 VSWR at full power?

Yes. Datasheet Section 5 confirms stable operation at 250 W output with 10:1 load mismatch across all phase angles at 650 MHz. This is enabled by the wide V_GS range (−8 V to +10 V), high V_DS rating (90 V), and internal layout symmetry between Drain A and Drain B terminals.

Is gate bias sequencing required during power-up?

No dedicated sequencing is mandated, but ST recommends applying V_GS before V_DD to prevent unintended conduction. A gate voltage of −2 V to 0 V should be established prior to ramping V_DD to 28 V, and gate drive must remain within −8 V to +10 V during all operational states to avoid latch-up or permanent damage.