BAT54A Schottky Diode:Application,Features and Pinout

The Schottky diode, also known as a Schottky barrier diode or hot-carrier Schottky diode, is a type of metal-semiconductor diode characterized by a low voltage drop of 0.15V to 0.45V and a very high switching speed. These diodes are used in a range of applications, including wave shaping, rectification, protection circuits, switching, and signal conditioning. Schottky diodes are available in various series on the market. This article provides a brief overview of the BAT54A Schottky Diode.

What is the BAT54A Schottky Diode?

The BAT54A is a Schottky diode offered in a Surface Mount Devices (SMD) package, known for its low turn-on voltage drop and fast switching capabilities. It includes a PN connection protection/guard ring for ESD and transient protection and is a “green” device, compliant with RoHS standards. These are planar Schottky diodes featuring an integrated guard ring for protection, formed by a PN-junction of a metal-semiconductor-metal, similar to a standard diode.

Typically, these Schottky diodes are utilized in protection and rectifier circuits. In low voltage circuits, where a voltage drop during conduction is not acceptable, devices with a low voltage drop during conduction are essential.

The BAT54A Schottky Diode is particularly useful in circuits where power efficiency is crucial. Its capability to deliver substantial current with minimal voltage drop ensures the high efficiency needed for battery-powered systems.

This diode is engineered for fast recovery, switching from forward conduction to reverse voltage blocking in just 5 nanoseconds, making it suitable for high-frequency applications.

BAT54A Pin Configuration/Pin Diagram:

The BAT54A Schottky Diode features a 3-terminal design, as illustrated in the pin diagram below. It comprises two Schottky diodes, with the three terminals labeled as cathode 1, cathode 2, and anode.

Pin 1: Cathode 1

This is the negative terminal of the first Schottky diode, as depicted in the diagram below. The current exits the device through this terminal.

Pin 2: Cathode 2

This serves as the negative terminal of the second Schottky diode, with the current also exiting the device through this terminal.

Pin 3: Anode

This terminal acts as the common positive terminal for both Schottky diodes. Current enters the device through this terminal.

The alternatives to BAT54A Schottky Diodes include BAT54, BAT54S, and BAT54C Schottky Diodes.

BAT54A Schottky Diode Specifications:

The specifications and electrical characteristics of the BAT54A Schottky Diode are as follows:

• Low forward voltage drop: 150-450mV
• Very small conduction losses
• Extremely fast switching speed
• High efficiency
• RoHS-compliant and lead-free device
• Maximum forward continuous current: 200mA
• Maximum reverse voltage: 30V
• Maximum forward surge current: 600mA
• Operating temperature range: -65°C to 150°C
• Maximum power dissipation: 200mW
• Available in SMD package
• Low capacitance: 10pF @ f=1MHz, Vr = 1V

Other characteristics include:

• Reverse voltage: 30V
• Forward current @ 25°C: 200mA
• Repetitive peak forward current @ 25°C: 300mA
• Non-repetitive peak forward current (square wave, tp < 10ms): 600mA
• Junction temperature: 150°C
• Ambient temperature range: -55°C to 150°C
• Storage temperature range: -65°C to 150°C
• Mounting: On PCB, single-sided copper, tin-plated, standard footprint
• Thermal resistance from junction to ambient in free air: 500K/W
• Reverse recovery time: 5nS
• Forward voltage:
• @ If = 0.1mA: 240mV
• @ If = 1mA: 320mV
• @ If = 10mA: 400mV
• @ If = 30mA: 500mV
• @ If = 100mA: 800mV
• Reverse current @ reverse voltage of 25V: 2 microAmps

Circuit Diagram / How to Use a BAT54A Schottky Diode:

The BAT54A Schottky Diode functions similarly to other rectifier diodes and can be used in protection rectifier circuits. Its characteristics can be summarized as follows.

The BAT54A Schottky Diode allows current to flow in the forward bias direction only when the anode is connected to a positive voltage and the cathode is connected to the ground. It will exhibit a leakage current of up to 0.1 mA in the reverse direction, only when the anode and cathode are both connected to the ground.

In a forward-biased condition, the voltage drop across the diode is a maximum of 1 V, whereas in a reverse-biased condition, the full supply voltage appears across the device.

In the circuit above, the BAT54A Schottky Diode is used as a protection diode for a microcontroller. The power supply provides power to the microcontroller, and the diodes are connected in series for protection.

Consider an application where the BAT54A Schottky Diode serves as a protection device for a microcontroller or microprocessor. The components required include a power supply unit with 3.5V, a BAT54A Schottky Diode, and a microprocessor or microcontroller.

The following diagram illustrates the circuit setup of a BAT54A Schottky Diode used to protect a microcontroller unit from reverse voltage.

In the circuit described, the 3.5V supply pin of the power supply unit is connected to the common anode terminal of the BAT54A Schottky Diode. The ground pin of the power supply unit is connected to the ground pin of the microcontroller/microprocessor unit. The common cathode 1 and cathode terminals of the BAT54A Schottky Diode are connected to the VCC pin of the microcontroller/microprocessor unit.

When the power supply is properly connected, the diode is forward biased, allowing current to flow. This results in a voltage at the microcontroller that is nearly equal to the power supply voltage due to the very low forward voltage drop of the diode.

If the polarity of the power supply is accidentally reversed, the diode becomes reverse biased, preventing any current from flowing through the circuit. According to the specifications of the BAT54A, no current will pass in this condition, and the microcontroller will experience zero voltage. This protects the microcontroller from damage due to incorrect polarity.

In the given circuit diagram, the BAT54A Schottky Diode serves to protect the sensitive microcontroller from reverse voltage. This same approach can be applied to other application circuits requiring protection from reverse voltage.

Applications/Where to Use:

The BAT54A Schottky Diode is used in the following applications:

• AC-DC filters
• Voltage regulators
• Ultra-high-speed switching applications
• Protection circuits
• Protection devices
• Line detectors
• Reverse polarity protection
• Voltage damping circuits

For more details, please refer to the BAT54A Schottky Diode Datasheet.

In summary, BAT54A Schottky Diodes are known for their low turn-on voltage, low energy loss, and fast recovery time, making them highly efficient. These characteristics make them an ideal choice for various semiconductor diode applications, including detector diodes, RF mixers, power rectifier circuits, and solar cell applications.