Diodes Incorporated B340AF-13

Overview

B340AF-13 from Diodes Incorporated is a 3.0A, 40V Schottky barrier rectifier in SMAF package, featuring 0.50V max forward voltage at 3A/25°C, 0.20mA max reverse leakage at 40V/25°C, and 35°C/W junction-to-ambient thermal resistance. It serves as a low-loss power rectifier in DC-DC boost stages, flyback snubbers, and reverse-polarity protection circuits.

For engineers reviewing the B340AF-13 datasheet, B340AF-13 pinout, B340AF-13 application, or B340AF-13 equivalent, key selection criteria include forward voltage drop at rated current, high-temperature reverse leakage stability, thermal resistance under PCB-mounted conditions, and SMAF package compatibility with automated SMT assembly.

Technical Context

This Schottky rectifier uses a planar metal-silicon junction to achieve low VF and fast switching with no minority-carrier storage delay. Its 40V VRRM rating targets 24V–36V input systems where margin against transient overvoltage is required without excessive conduction loss.

Thermal performance is defined for mounting on a 2"×2" aluminum board (RθJA = 35°C/W), and its 6.0°C/W RθJC enables effective heat transfer to metal-core PCBs or heatsinks. Reverse leakage remains below 0.30mA up to +125°C, supporting reliable operation in automotive under-hood environments.

Key Specifications

Pinout & Package

Package: SMAF (Surface-Mount Axial Flat), 2-pin, cathode-banded, RoHS-compliant matte tin finish on copper leadframe. Dimensions: 4.60 × 2.95 × 1.10 mm (L × W × H), weight ≈ 0.036 g.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Schottky rectifier applications.

Compared with SS34-E3/57T and MBR340F, B340AF-13 delivers the lowest combination of forward voltage and high-temperature leakage among SMAF-packaged 40V Schottkys, making it optimal for thermally demanding 24V industrial and automotive auxiliary supplies.

Availability

B340AF-13 is available at Aetrix Electronics and suitable for 24V DC-DC boost converters, solar charge controllers, flyback snubbers, and reverse polarity protection circuits requiring stable component supply and RoHS-compliant sourcing.

Supply support for B340AF-13 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, with design, manufacturing, and sales operations across Asia, Europe, and the Americas.

The B340AF belongs to Diodes' general-purpose Schottky rectifier product line, engineered for high-efficiency, high-reliability power conversion in industrial, computing, and automotive subsystems where low VF and thermal stability are critical.

FAQ

Is B340AF-13 suitable for automotive under-hood applications?

Yes - it is rated for TJ = –55°C to +150°C, exhibits ≤0.30mA reverse leakage at 40V/125°C, and is manufactured in IATF 16949-certified facilities. While not AEC-Q101 qualified out-of-box, its thermal and leakage performance meets baseline requirements for non-safety-critical under-hood circuits such as HVAC fan drivers or lighting modules.

What is the maximum continuous power dissipation for B340AF-13 on a standard FR-4 PCB?

At TA = +70°C, with RθJA = 35°C/W, the maximum continuous power is 2.3W (calculated as (150°C − 70°C)/35°C/W). However, due to derating curves in Figure 4, average forward current must be limited to ~2.0A at this ambient, yielding ~1.0W actual dissipation (2.0A × 0.50V).

Does B340AF-13 have a specified junction capacitance, and how does it affect high-frequency operation?

Yes - typical CT is 120pF at VR = 4.0V, f = 1MHz (per datasheet Figure 3). This low capacitance minimizes displacement current and EMI in switching frequencies up to 500kHz, making it suitable for high-frequency boost and flyback topologies without requiring snubber networks.

Can B340AF-13 replace B345AF-13 in a 40V-rated design?

Yes - B340AF-13 has identical package, pinout, VF, and thermal specs as B345AF-13, differing only in VRRM (40V vs. 45V) and IR (0.20mA vs. 0.30mA at 25°C). In a 40V system with tight leakage budget, B340AF-13 provides lower IR and is the preferred choice.