BLF989SU

Overview

The BLF989SU is a dual N-channel LDMOS RF power transistor designed for broadcast and industrial applications in the 400 MHz to 860 MHz frequency range. It features a drain-source voltage of 50 V, an average output power of 135 W per section (270 W total), and a typical power gain of 22.5 dB at 700 MHz. The device operates with a quiescent current of 650 mA per section and achieves a drain efficiency of up to 35%. It utilizes a SOT539B earless flanged balanced ceramic package.

Feature Summary

• Designed for broadband and Doherty operation
• Integrated dual-sided ESD protection
• Excellent ruggedness against load mismatch
• High power gain and efficiency

Applications

• Broadcast transmitter applications in the UHF band
• Digital and analog broadcasting
• Industrial, scientific and medical applications

Procurement Notes

Verify the specific ordering suffix 'S' corresponds to the SOT539B earless flanged package variant rather than the standard SOT539A version. Confirm RoHS compliance status directly with the manufacturer or authorized distributor as specifications may vary by production batch. Ensure proper handling precautions are observed due to electrostatic sensitivity.

Selection Notes

Select this component for high-power UHF applications requiring robust performance in Class-AB broadband or symmetric Doherty configurations. Verify thermal management requirements based on the junction-to-case thermal resistance of 0.13 K/W. Ensure the operating frequency falls within the specified 400 MHz to 860 MHz range for optimal gain and efficiency characteristics.

Part Context

The BLF989SU belongs to Ampleon's UHF power LDMOS transistor family, specifically engineered for broadcast and industrial sectors. It serves as a high-reliability alternative for digital and analog transmitter designs, offering enhanced stability and power control capabilities compared to previous generation devices.

Replacement Considerations

The BLF989 (SOT539A) is the primary functional equivalent with a different physical package configuration. Direct substitution requires verifying mechanical fit and mounting hole alignment between the flanged SOT539A and earless SOT539B variants.

FAQ

What is the maximum load mismatch the BLF989SU can withstand?

The device can withstand a load mismatch corresponding to a Voltage Standing Wave Ratio (VSWR) of 40:1 through all phases under specified test conditions.

What is the typical drain efficiency at 700 MHz?

In a Class-AB broadband application at 700 MHz, the typical drain efficiency is 35%.

How is the gate-source threshold voltage defined?

The gate-source threshold voltage (VGS(th)) is typically 2.2 V, with a minimum of 1.5 V and a maximum of 2.5 V when measured at VDS = 10 V and ID = 240 mA.