NXP Semiconductors BF1108R,235

Overview

BF1108R,235 from NXP Semiconductors is a silicon RF switch combining a depletion-mode MOSFET and an integrated band-switching diode in an SOT143R package. It delivers ≤2 dB on-state insertion loss and ≥30 dB off-state isolation up to 1 GHz, with 12 Ω typical R_DS(on) and −3 V gate-source pinch-off voltage. It serves as a low-loss RF signal path selector in tuner front-ends and transceiver antenna switching.

For engineers reviewing the BF1108R,235 datasheet, BF1108R,235 pinout, BF1108R,235 application, or BF1108R,235 equivalent, key selection criteria include RF insertion loss at 1 GHz, isolation performance under 5 V control bias, gate isolation via integrated diode, ESD-sensitive handling requirements, and SOT143R reverse-pin compatibility with legacy layouts.

Technical Context

The BF1108R,235 implements a monolithic RF switch architecture where the depletion-mode FET provides the main signal path and the co-packaged diode isolates the gate from ground during off-state operation-enabling low-loss RF conduction without external DC blocking. Its static characteristics are defined at T_j = 25 °C, with guaranteed V_GS(p) between −3 V and −4 V and I_DSX ≤10 µA at V_GS = −5 V.

Dynamic RF performance is characterized using 50 Ω source/load impedance and specified for both 50 Ω and 75 Ω systems. On-state insertion loss is measured with V_SK = V_DK = 0 V and zero diode forward current; off-state isolation requires V_SK = V_DK = 5 V and 1 mA diode forward current per test circuit Figure 3.

Key Specifications

Pinout & Package

SOT143R plastic surface-mounted package (4 leads, reverse pinning), 3.0 × 1.4 × 1.1 mm body size, thermal resistance R_th(j-sp) = 250 K/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BF1108,215, the BF1108R,235 offers direct SOT143R footprint compatibility for reverse-pin layouts, while QM11036 provides measurable RF performance gains at the cost of control voltage and package incompatibility-making BF1108R,235 optimal for drop-in replacements in existing SOT143R designs.

Availability

BF1108R,235 is available at Aetrix Electronics and suitable for VCR tuners, transceiver antenna switching, FM/AM radio front-ends, and RF test equipment requiring stable component supply and long-lifecycle support.

Supply support for BF1108R,235 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 is a global semiconductor company headquartered in Eindhoven, Netherlands, specializing in secure connectivity solutions for automotive, industrial, and consumer applications.

The BF1108R,235 belongs to NXP's legacy silicon RF switch product line, engineered specifically for cost-sensitive, high-volume analog RF signal routing in broadcast and communications equipment up to 1 GHz.

FAQ

What is the maximum operating frequency of the BF1108R,235?

The BF1108R,235 is characterized for RF switching applications up to 1 GHz, with typical on-state insertion loss of 1.3 dB and off-state isolation of 38 dB at exactly 1 GHz under 50 Ω conditions. Performance remains within specification up to 1 GHz; operation beyond this frequency is not guaranteed by the datasheet and may degrade insertion loss and isolation.

How does the integrated diode function in the BF1108R,235?

The integrated diode in the BF1108R,235 connects between the FET gate (pin 1) and cathode (pin 2), enabling gate isolation from ground during off-state operation. When 5 V is applied to pins 2 and 4, the diode conducts ~1 mA forward current, pulling the gate negative relative to source/drain and turning the depletion-mode FET off-achieving high isolation without external components.

Is the BF1108R,235 pin-compatible with the BF1108,215?

No, the BF1108R,235 is not pin-compatible with the BF1108,215. The BF1108R,235 uses SOT143R (reverse pinning), where pin 2 is the diode cathode and pin 3 is source; the BF1108,215 uses SOT143B (standard pinning), where pin 2 is source and pin 3 is diode cathode. PCB layout modification is required for substitution.

What ESD precautions are required when handling the BF1108R,235?

The BF1108R,235 is classified as ESD-sensitive (Class 1B per JEDEC JS-001). Handling requires grounded wrist straps, conductive foam storage, ionized air workstations, and avoidance of direct contact with pin 1 (gate/diode anode). Board-level assembly must follow IPC-610 Class 2 guidelines to prevent gate oxide damage from transient voltages exceeding ±2 kV HBM.

Can source and drain be interchanged in the BF1108R,235?

Yes, source (pin 3) and drain (pin 4) are interchangeable in the BF1108R,235, as confirmed in the official pinning information section. This symmetry allows flexible RF layout routing and bidirectional signal path design without performance penalty-both terminals exhibit identical R_DS(on), capacitance, and breakdown ratings.