STMicroelectronics SD1488

Overview

SD1488 from STMicroelectronics is a 12.5 V, 38 W Class C NPN RF bipolar transistor in M111 plastic package, designed for UHF land mobile radio amplification at 470 MHz with 5.8 dB power gain and 50% collector efficiency in common-emitter configuration.

For engineers reviewing the SD1488 datasheet, SD1488 pinout, SD1488 application, or SD1488 equivalent, this device is selected for high-efficiency broadband RF power stages in 450–512 MHz transceivers where VSWR tolerance, thermal robustness, and output power stability under dynamic load are critical design requirements.

Technical Context

The SD1488 operates in Class C mode with fixed 12.5 V supply, delivering minimum 38 W RF output at 470 MHz under 10 W drive. Its diffused emitter resistors enable infinite VSWR survivability at rated conditions, eliminating need for external protection circuitry in mobile base station final stages.

It features a silicon planar epitaxial structure with common-emitter topology, optimized for broadband operation across 450–512 MHz. Thermal resistance is 1.5 °C/W (junction-to-case), supporting high-power dissipation up to 117 W with appropriate heatsinking.

Key Specifications

Pinout & Package

The SD1488 is housed in the M111 plastic epoxy-sealed package - a 4-lead flange-mount outline with isolated collector tab for direct heatsink attachment and mechanical stability in high-vibration mobile environments.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MRF454 and PD57008, the SD1488 offers optimal balance of proven UHF performance, mechanical ruggedness in M111, and cost-effectiveness for dedicated 450–512 MHz land mobile systems - especially where infinite VSWR tolerance and thermal simplicity are prioritized over raw power or wideband flexibility.

Availability

SD1488 is available at Aetrix Electronics and suitable for land mobile radio transceivers, UHF base station repeaters, public safety emergency communications, and industrial dispatch systems requiring stable component supply and long-term lifecycle support.

Supply support for SD1488 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, specializing in analog, power, and RF solutions for industrial, automotive, and communications markets.

The SD1488 belongs to ST's legacy RF bipolar transistor product line, engineered specifically for rugged, high-efficiency UHF power amplification in mission-critical mobile radio infrastructure.

FAQ

Is the SD1488 still in active production?

No - the SD1488 is marked "Obsolete Product(s)" in its official STMicroelectronics documentation (Rev. 2, June 2004). However, Aetrix Electronics maintains legacy inventory with full traceability and provides engineering support for ongoing maintenance and repair of fielded equipment.

What is the recommended heatsink interface for the M111 package?

Use thermally conductive silicone grease or phase-change pad between the isolated collector flange and aluminum heatsink. Torque mounting screws to 0.5–0.7 N·m. Ensure flatness ≤ 0.05 mm across the flange surface to maintain <1.5 °C/W effective thermal resistance.

Can the SD1488 be used in Class AB mode?

It is not characterized or guaranteed for Class AB operation. The device is optimized and tested exclusively for Class C switching-mode amplification at 12.5 V. Using it in Class AB risks thermal instability and premature failure due to lack of safe operating area (SOA) data for linear operation.

Does the dual-emitter configuration require separate grounding paths?

Yes - pins 3 and 4 must both be connected to the same low-inductance RF ground plane, preferably via separate short traces or a common copper pour. This preserves the intended current division and VSWR resilience; omitting one emitter connection degrades mismatch tolerance and thermal distribution.