STMicroelectronics LET9045TR

Overview

LET9045TR from STMicroelectronics is a common-source N-channel enhancement-mode lateral MOSFET optimized for RF power amplification up to 1 GHz. It delivers 45 W output power with 18.5 dB gain at 960 MHz under 28 V supply and 300 mA quiescent drain current, featuring 1.2 °C/W junction-to-case thermal resistance and PowerSO-10RF gull-wing plastic package.

For engineers reviewing the LET9045TR datasheet, LET9045TR pinout, LET9045TR application, or LET9045TR equivalent, key selection criteria include RF gain flatness across 800–1000 MHz, load mismatch tolerance (10:1 VSWR), ESD protection class M3, and thermal performance in base station PA stages requiring stable high-power SMD packaging.

Technical Context

The LET9045TR operates in common-source configuration with fixed 28 V drain bias and 300 mA IDQ, supporting broadband linear amplification from 800 MHz to 1 GHz. Its lateral LDMOS structure provides inherent thermal stability and high linearity, validated by 60–65% drain efficiency and <0.8 pF CRSS for low feedback capacitance.

Designed for base station transmitters, it integrates ESD protection per machine model Class M3 and meets JEDEC-compliant PowerSO-10RF mechanical specifications-including 0.8–1.1 mm lead length, 9.4–9.6 mm body width, and 13.85–14.35 mm overall length-enabling automated SMT assembly without thermal derating penalties.

Key Specifications

Pinout & Package

LET9045TR uses the PowerSO-10RF gull-wing plastic package (JEDEC-compliant SMD), with three active terminals: Gate (pin 1), Source (pins 2–5 and 7–10), and Drain (pin 6). The Source is internally bonded across eight leads for low-inductance grounding and thermal spreading.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MRF6V2010N and PD85004, LET9045TR offers optimal balance of SMD manufacturability, 45 W output, and 1.2 °C/W thermal resistance in a JEDEC-standard gull-wing package-making it ideal for cost-sensitive, high-volume 900 MHz base station PA designs where proven reliability outweighs raw power density.

Availability

LET9045TR is available at Aetrix Electronics and suitable for macrocell base stations, public safety radios, ISM industrial heaters, and UHF RFID readers requiring stable component supply with tape-and-reel delivery for SMT production lines.

Supply support for LET9045TR 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, digital, and mixed-signal ICs for automotive, industrial, and communications markets.

The LET9045TR belongs to ST's LdmoST RF power transistor family, engineered specifically for high-linearity, high-efficiency broadband amplification in commercial wireless infrastructure operating below 1 GHz.

FAQ

What is the recommended gate bias network for LET9045TR in Class AB operation?

A two-resistor divider (R1 = 10 kΩ, R2 = 4.7 kΩ) with 100 nF bypass capacitor to ground sets VGS ≈ 4.5 V for IDQ = 300 mA. A 10 Ω gate stopper resistor suppresses VHF oscillation, and DC blocking between driver and gate prevents bias disruption from signal swing.

Does LET9045TR require an external heatsink when operating at 45 W output?

No external heatsink is required if the PCB provides ≥25 cm² of 2-oz copper on the Source pads connected to an internal ground plane. With RthJC = 1.2 °C/W and ambient ≤50 °C, junction temperature remains below 140 °C-well within the 165 °C limit-even at full POUT.

Can LET9045TR be used in Doherty amplifier configurations?

Yes-its symmetric gain and phase response across 800–1000 MHz, combined with low CRSS and high linearity (65% efficiency), make it suitable as both carrier and peaking amplifier in Doherty architectures targeting LTE and 5G NR TDD bands.

What is the maximum allowable VSWR at the drain port during continuous operation?

LET9045TR is rated for indefinite operation at 10:1 VSWR across all phase angles at 960 MHz, provided VDS does not exceed 80 V. This is enabled by its lateral LDMOS structure and integrated field plate, which distribute voltage stress and prevent localized avalanche.