NXP Semiconductors BLF4G20S-110B,112

Overview

BLF4G20S-110B from NXP Semiconductors (formerly Philips Semiconductors) is a 110 W UHF LDMOS power transistor designed for base station RF power amplification in the 1800–2000 MHz band. It delivers 48 W average output power in GSM EDGE mode at 1930–1990 MHz, with 13.8 dB gain, 38.5% drain efficiency, −61 dBc ACPR400, and 2.1% EVMrms under 28 V/650 mA bias.

For engineers reviewing the BLF4G20S-110B datasheet, BLF4G20S-110B pinout, BLF4G20S-110B application, or BLF4G20S-110B equivalent, this device is selected for high-ruggedness, broadband UHF PA stages in multicarrier GSM/EDGE/CDMA base stations where thermal stability, load mismatch tolerance (VSWR = 10:1), and internally matched 50 Ω input/output are critical design requirements.

Technical Context

The BLF4G20S-110B operates in class-AB with fixed 28 V drain supply and quiescent drain current of 650 mA. Its LDMOS structure enables high breakdown voltage (65 V V_(BR)DSS) and low R_DS(on) (90 mΩ), supporting robust CW and modulated signal handling up to 110 W PEP.

Internally matched for 50 Ω systems, it achieves −10 dB input return loss at 100 W AV and maintains stable intermodulation performance: −29 dBc IMD3, −39.5 dBc IMD5, and −53.5 dBc IMD7 at 100 W average output - confirming suitability for linear multicarrier amplification without external matching networks.

Key Specifications

Pinout & Package

BLF4G20S-110B uses the SOT502B package: earless flanged ceramic LDMOS package with two leads and no mounting holes. The flange is electrically connected to the source terminal and serves as the primary thermal path and RF ground reference.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MRF6V2150N and PD57018, the BLF4G20S-110B offers optimal balance of ruggedness (VSWR 10:1), internal 50 Ω matching, and proven GSM/EDGE linearity - making it the preferred choice for cost-sensitive, production-ready macrocell PA designs operating strictly within 1800–2000 MHz.

Availability

BLF4G20S-110B is available at Aetrix Electronics and suitable for GSM base station transmitters, EDGE multicarrier amplifiers, and CDMA2000 infrastructure requiring stable component supply, long-lifecycle support, and traceable sourcing.

Supply support for BLF4G20S-110B 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

NXP Semiconductors (originally Philips Semiconductors) is a global leader in high-performance RF power solutions, specializing in silicon-based LDMOS and GaN transistors for wireless infrastructure.

The BLF4G20S-110B belongs to NXP's UHF LDMOS portfolio, engineered specifically for carrier-class base station power amplifiers demanding high efficiency, ruggedness, and broadband linearity in 1.8–2.0 GHz cellular bands.

FAQ

What is the maximum continuous drain current rating for BLF4G20S-110B?

The absolute maximum rated drain current for BLF4G20S-110B is 12 A, as specified in Table 4 (Limiting Values) of the official datasheet. This rating applies under transient conditions and must not be exceeded during normal operation. For sustained CW operation at 110 W, the typical drain current is approximately 4.5 A at 28 V, well within safe limits. Always verify thermal derating based on actual case temperature in the BLF4G20S-110B application environment.

Does BLF4G20S-110B require external matching components?

No, the BLF4G20S-110B is internally matched to 50 Ω at both input and output across its 1800–2000 MHz operating band. This eliminates the need for external matching networks in standard class-AB amplifier designs, simplifying PCB layout and improving production yield. However, harmonic filtering and DC blocking remain necessary, and fine-tuning may be applied for specific linearity or efficiency targets in the BLF4G20S-110B implementation.

What is the thermal resistance from junction to case for BLF4G20S-110B at 100 W output?

At 100 W load power, the BLF4G20S-110B exhibits a typical thermal resistance of 0.65 K/W from junction to case (R_th(j-case)), with a maximum of 0.74 K/W, as documented in Table 5. This low thermal resistance enables efficient heat transfer to the heatsink when the flange is properly soldered to a large copper area. Maintaining case temperature ≤80 °C ensures reliable long-term operation of the BLF4G20S-110B in base station environments.

Can BLF4G20S-110B operate safely under high VSWR conditions?

Yes, the BLF4G20S-110B is specifically characterized for ruggedness: it withstands a load mismatch of VSWR = 10:1 through all phase angles at 28 V, 650 mA I_Dq, 110 W CW, and 1990 MHz - per Section 7.1 of the datasheet. This capability eliminates the need for external circulators in many outdoor base station deployments, directly enhancing system reliability and reducing bill-of-materials cost for the BLF4G20S-110B design.

What is the gate-source threshold voltage range for BLF4G20S-110B?

The gate-source threshold voltage (V_GS(th)) for BLF4G20S-110B is specified as 2.5 V (min) to 3.5 V (max), with a typical value of 3.1 V, measured at V_DS = 10 V and I_D = 180 mA (Table 6). This tightly controlled threshold enables consistent bias point setting across production lots and supports stable class-AB operation in the BLF4G20S-110B amplifier stage without excessive gate drive variation.