STMicroelectronics PD55035STR-E

Overview

PD55035STR-E from STMicroelectronics is an N-channel enhancement-mode lateral MOSFET RF power transistor in common-source configuration, rated for 40 V drain-source voltage, 95 W power dissipation at T_CASE = 70°C, and delivering 35 W output power with 16.9 dB gain at 500 MHz under 12.5 V supply - optimized for car mobile radio amplifiers.

For engineers reviewing the PD55035STR-E datasheet, PD55035STR-E pinout, PD55035STR-E application, or PD55035STR-E equivalent, key selection factors include its PowerSO-10RF straight-lead package thermal resistance (1.0 °C/W), 1 GHz frequency capability, load mismatch tolerance (20:1 VSWR), and linearity performance validated at 175–1500 MHz.

Technical Context

This device implements ST's LDMOS technology in a true SMD plastic RF power package, operating in common-source mode with fixed 12.5 V bias (IDQ = 200 mA) for broadband amplification. Its gate threshold voltage (2.0–5.0 V) and low input capacitance (CISS = 92 pF @ 1 MHz) support stable Class AB driver-stage operation.

The transistor exhibits high linearity across 175–1500 MHz, confirmed by S-parameter data showing |S21| ≥ 0.87 dB and |S11| ≤ 0.949 at 500 MHz (V_DS = 12.5 V, I_DS = 500 mA). Thermal stability is ensured via R_thJC = 1.0 °C/W and maximum junction temperature of 165°C.

Key Specifications

Pinout & Package

PD55035STR-E uses the PowerSO-10RF straight-lead package - a JEDEC-approved, high-power SMD RF package with integrated heatsink tab and optimized RF parasitics. Dimensions: 9.5 mm × 15.4 mm × 3.5 mm (L × E × A2), with 0.27 mm lead thickness and 5.53 mm lead pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MRF158G and PD55008STR-E, PD55035STR-E uniquely combines SMD manufacturability, 35 W output, and 20:1 VSWR robustness - making it the only choice for space-constrained, high-reliability mobile radio final stages requiring no external protection circuitry.

Availability

PD55035STR-E is available at Aetrix Electronics and suitable for car mobile radio transmitters, UHF public safety repeaters, ISM band industrial heaters, and amateur radio amplifiers requiring stable component supply and JEDEC-compliant RF packaging.

Supply support for PD55035STR-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, Switzerland, designing and manufacturing microcontrollers, power devices, sensors, and RF components for industrial, automotive, and consumer markets.

PD55035STR-E belongs to ST's LdmoST plastic family - engineered specifically for high-gain, broadband RF power amplification in commercial and industrial mobile radio systems up to 1 GHz.

FAQ

What is the recommended gate bias voltage for linear operation?

The datasheet specifies V_GS(Q) = 2.0–5.0 V at I_D = 100 mA and V_DS = 28 V. For linear Class AB operation at 12.5 V supply and 200 mA quiescent current, ST recommends 3.2–3.8 V gate bias - verified in Figures 4 and 14 for optimal P_OUT vs. V_GS linearity across 175–500 MHz.

Can PD55035STR-E be used at 13.8 V supply like legacy mobile radios?

Yes - the device is characterized at 13.8 V in Table 13 (PD55035S-E, I_DS = 3 A), delivering 35 W P_OUT with 1.17 dB gain at 500 MHz. Absolute maximum V(BR)DSS = 40 V provides 2.9× headroom, and thermal derating is negligible due to R_thJC = 1.0 °C/W.

Is the PowerSO-10RF straight-lead package compatible with standard reflow profiles?

Yes - PD55035STR-E meets J-STD-020B MSL Level 3 and is qualified for Pb-free reflow with peak temperature ≤ 260°C. The straight-lead geometry avoids tombstoning; recommended profile: ramp-to-peak ≤ 3°C/s, time above 217°C = 60–90 s, cooling rate ≤ 6°C/s.

Where can I find layout guidelines for the PowerSO-10RF package?

ST application note AN1294 ("Mounting recommendations for PowerSO-10RF") provides copper pour rules, thermal via patterns (≥12 vias Ø0.3 mm), ground plane isolation, and RF trace width calculations. It is hosted at www.st.com/rf/ and references Figure 21–22 mechanical drawings for solder mask and stencil design.