STMicroelectronics LET20045C

Overview

LET20045C from STMicroelectronics is a common-source n-channel enhancement-mode lateral MOSFET RF power transistor designed for broadband base station amplifiers up to 2.0 GHz, delivering 54 W output power at 28 V with 13.3 dB gain and 45% drain efficiency at 2000 MHz under 2.5 W input drive.

For engineers reviewing the LET20045C datasheet, LET20045C pinout, LET20045C application, or LET20045C equivalent, this device is selected for high-linearity, high-efficiency RF final-stage amplification in IS-95/CDMA infrastructure where thermal stability, load mismatch tolerance (10:1 VSWR), and BeO-free packaging are critical design requirements.

Technical Context

The LET20045C operates in common-source configuration with fixed gate bias (VGS(Q) = 2.0–5.0 V) and supports broadband matching via defined ZIN (input) and ZDL (drain load) impedance data at 2000 MHz. Its lateral MOSFET structure enables stable gain across supply voltages from 20 V to 36 V.

Thermal performance is defined by Rth(JC) = 1.0 °C/W and TJ(max) = 200 °C, enabling high-power operation at TCASE = 70 °C with PDISS = 130 W. It sustains full-rated RF performance under 10:1 load VSWR across all phase angles without damage.

Key Specifications

Pinout & Package

Package: M243 (.230 × .360 inch, 2-lead, non-hermetic with flange), BeO-free ceramic-metal construction compliant with RoHS and ECOPACK® standards.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MRF6VP2600HR5 and PD85004, the LET20045C offers optimal balance of 54 W output, 1.0 °C/W thermal resistance, and proven 10:1 VSWR ruggedness in cost-sensitive 2G/3G base station upgrades where GaN complexity or derated LDMOS output is not required.

Availability

LET20045C is available at Aetrix Electronics and suitable for CDMA base station transmitters, ISM band amplifiers, public safety radio repeaters, and avionics communication test benches requiring stable component supply and long-term industrial lifecycle support.

Supply support for LET20045C 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, designing and manufacturing analog, MCU, power, and RF components for industrial, automotive, and communications markets.

The LET20045C belongs to the LdmoST family of lateral DMOS RF transistors, engineered specifically for high-gain, high-efficiency, and thermally robust operation in commercial wireless infrastructure amplifiers up to 2.0 GHz.

FAQ

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

The LET20045C specifies VGS(Q) = 2.0–5.0 V at ID = 100 mA and VDS = 28 V. For reliable Class AB operation at IDQ = 500 mA, a fixed gate bias of 3.2–3.8 V is recommended using a temperature-compensated resistive divider, verified by the typical gain vs. IDQ curves in Figure 3.

Can the LET20045C be operated safely at 36 V with full 65 W output?

Yes - the device is rated for V(BR)DSS = 80 V and delivers 65 W POUT with 12.5 dB gain at 36 V, 2000 MHz, and IDQ = 500 mA. Thermal design must ensure case temperature remains ≤70 °C to sustain 130 W PDISS, per absolute maximum ratings in Table 2.

Is external gate protection required against ESD or RF feedback?

Yes - although IGSS ≤ 1 µA, the gate oxide is sensitive. ST recommends a 10 Ω series resistor and parallel 100 pF capacitor at the gate terminal, plus a 10 V Zener diode between gate and source, as shown in application note AN4302 for LdmoST devices.

Does the M243 package require solder paste reflow or is it through-hole mounted?

The M243 is a flanged metal-ceramic package with two leads intended for through-hole mounting and mechanical clamping to a heatsink. It is not reflow-solderable; mounting requires conductive thermal compound, spring-loaded screws, and torque-controlled fastening per ST's M243 mechanical drawing (Table 7).