STMicroelectronics BAT47

Overview

BAT47 from STMicroelectronics is a small-signal Schottky diode in DO-35 package, designed for low-voltage, high-speed switching applications with 20 V repetitive peak reverse voltage, 350 mA forward continuous current, and 0.5 V forward voltage at 30 mA. It operates across –65 °C to +150 °C junction temperature and features low capacitance (12 pF at 1 V VR) and fast recovery for signal routing and clamping in portable power management.

For engineers reviewing the BAT47 datasheet, BAT47 pinout, BAT47 application, or BAT47 equivalent, key selection criteria include its low VF (0.25 V at 0.1 mA), low IR (4 µA at 20 V VR, 25 °C), 300 °C/W junction-to-ambient thermal resistance, and DO-35 mechanical compatibility with legacy through-hole layouts.

Technical Context

The BAT47 uses a metal–silicon Schottky barrier structure enabling low turn-on voltage and minimal minority-carrier storage, resulting in negligible reverse recovery time. Its 20 V VRRM rating and 7.5 A non-repetitive surge capability support transient-tolerant input protection in DC-DC converters and battery-fed circuits.

Thermal performance is defined by 300 °C/W Rth(j–a) on infinite heatsink with 4 mm lead length, and soldering tolerance up to 230 °C for 10 s at 4 mm from case. Junction temperature must remain ≤+150 °C under steady-state operation at rated IF.

Key Specifications

Pinout & Package

DO-35 glass axial package with cathode identified by ring marking; leads are tinned copper alloy, 0.458–0.558 mm diameter; overall length 3.05–4.50 mm, body diameter 1.53–2.00 mm; weight 0.015 g.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BAT47, 1N5711 offers higher reverse voltage but sacrifices low-current VF and thermal robustness, while BAT54 enables miniaturization at the cost of through-hole compatibility and single-diode simplicity.

Availability

BAT47 is available at Aetrix Electronics and suitable for USB port protection, RF detector clamping, low-power sensor biasing, and DC-DC converter OR-ing requiring stable component supply across industrial and consumer production cycles.

Supply support for BAT47 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, designing and manufacturing analog, microcontroller, power, and sensing solutions for industrial, automotive, and consumer markets.

The BAT series targets general-purpose discrete signal conditioning, emphasizing low VF, fast switching, and rugged packaging for cost-sensitive, high-volume applications like power management and interface protection.

FAQ

What is the maximum allowable junction temperature for continuous operation of BAT47?

The BAT47 has a specified junction temperature range of –65 °C to +150 °C. For continuous operation at full 350 mA forward current, junction temperature must be maintained ≤+150 °C, which requires thermal design accounting for its 300 °C/W Rth(j–a) and ambient conditions. Derating is necessary above 25 °C ambient.

Can BAT47 be used in place of BAT48 in a 20 V circuit?

Yes - BAT47 is rated for 20 V VRRM and matches BAT48's electrical behavior below that threshold. However, BAT48 supports up to 40 V reverse voltage and exhibits higher IR at 20 V (10 µA vs. BAT47's 4 µA). In 20 V circuits where leakage sensitivity is critical, BAT47 provides tighter IR control.

Is BAT47 suitable for RF signal detection at 900 MHz?

Yes - with 12 pF capacitance at 1 V reverse bias and negligible stored charge, BAT47 functions effectively as a zero-bias RF detector diode up to 900 MHz. Its low VF and fast response preserve signal fidelity in crystal radio and RFID reader front-ends where harmonic generation must be minimized.

Does BAT47 have built-in ESD protection, and what level does it support?

Yes - the BAT47 datasheet states integrated protection against excessive voltage such as electrostatic discharges. While no specific HBM or CDM rating is published, its robust metal–silicon Schottky construction and 230 °C soldering tolerance indicate inherent resilience to common handling ESD events, making external TVS redundant in many I/O protection roles.