STMicroelectronics PD85025STR-E

Overview

PD85025STR-E from STMicroelectronics is a 10 W PEP UHF LDMOS RF power transistor designed for base station and mobile radio final-stage amplification in 340–520 MHz OFDM systems. It delivers ≥16.5 dB gain at 15 V supply, supports 20:1 load mismatch tolerance, and operates with 220 mA quiescent drain current.

For engineers reviewing the PD85025STR-E datasheet, PD85025STR-E pinout, PD85025STR-E application, or PD85025STR-E equivalent, key selection criteria include PEP output capability, harmonic suppression (H2 ≤ –37 dBc, H3 ≤ –60 dBc), thermal stability without BeO, and ruggedness under VSWR stress in 2-way radio transmitters.

Technical Context

This LDMOS device employs a silicon-based vertical structure optimized for high-efficiency linear amplification in UHF broadband applications. Its 15 V operation, 1.25 A peak drain current at 10 W PEP, and integrated thermal design enable stable performance across temperature and mismatch conditions.

The transistor is characterized for two-tone testing at 600 kHz tone spacing, delivering IMD3 < –27 dBc at full output. Harmonic distortion is tightly controlled: second harmonic ≤ –37 dBc, third harmonic ≤ –60 dBc - critical for spectral mask compliance in OFDM and TETRA systems.

Key Specifications

Pinout & Package

PD85025STR-E uses a TO-247-3L package with isolated tab. The drain is connected to the metal tab for direct heatsink mounting; source and gate are on leads #1 and #2 respectively.

Key Features

Applications

Availability

PD85025STR-E is available at Aetrix Electronics and suitable for UHF land mobile radio, public safety base stations, OFDM wireless microphone systems, and digital TV exciters requiring stable component supply and long-term industrial availability.

Supply support for PD85025STR-E 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, delivering automotive, industrial, and power discrete solutions with emphasis on reliability and manufacturability.

PD85025STR-E belongs to ST's LDMOS RF power transistor product line, engineered specifically for rugged, high-efficiency UHF amplification in mission-critical mobile and infrastructure radios.

FAQ

What is the maximum safe operating junction temperature for PD85025STR-E?

The absolute maximum junction temperature is +200°C, with recommended continuous operation below +150°C case temperature. Thermal derating begins at 125°C case, requiring heatsink design that maintains θ_JC ≤ 0.9°C/W for full 10 W PEP output.

Does PD85025STR-E require external gate protection diodes?

Yes - the gate oxide is sensitive to ESD and RF overdrive. ST recommends a series 10 Ω resistor and parallel 5.1 V Zener (e.g., BZX284C5V1 as used on STEVAL-TDR022V1) between gate and source to clamp transient voltages within ±10 V.

Can PD85025STR-E be operated in Class C for higher efficiency?

No - it is characterized and qualified only for Class AB linear operation. Class C biasing violates the specified Idq = 220 mA condition and risks gain compression, increased IMD, and premature failure due to uncontrolled peak drain current.

Is the PD85025STR-E pin-compatible with PD85025-E?

Yes - both share identical TO-247-3L mechanical outline and terminal assignment (source, gate, drain-tab). The 'STR-E' suffix denotes tape-and-reel packaging; electrical and thermal specs are identical to the tube-packaged PD85025-E.