ESAD92-02R

The ESAD92-02R is a surface-mount single-phase bridge rectifier from Littelfuse’s ESAD92 series, designed for low-to-medium power offline power supply applications where space efficiency and automated assembly are important. As a full-wave bridge rectifier, it integrates four discrete diode chips into a single 4-pin surface-mount package, converting alternating current (AC) input into pulsating direct current (DC) output — a fundamental building block of nearly all AC-input power supplies. The ESAD92-02R is rated for 2 A average forward current and 200 V repetitive peak reverse voltage, making it suitable for low-power offline flyback converters, battery chargers, LED drivers, consumer electronics power supplies, and general-purpose AC-DC rectification up to approximately 100-150 W (depending on line voltage and cooling). The diode chips are fabricated using glass-passivated technology, where a thin glass layer passivates the diode junction edges, providing excellent stability, low leakage current, and high reliability compared to unpassivated or plastic-passivated devices. The glass passivation also improves the device’s ability to withstand voltage transients and temperature cycling. The surface-mount ESAD package (also called SOP-4 or DBS package) provides a compact form factor with a footprint of approximately 4.8mm × 4.0mm, offering significant space savings compared to traditional through-hole bridge rectifier packages (like the DIP-4 BR series). The small size and SMD format make these bridge rectifiers ideal for compact power adapters, chargers, and slim-line consumer electronics where PCB space is at a premium. Despite its small size, the ESAD92-02R can handle surge currents of up to 50 A (8.3 ms half-sine) — sufficient for the inrush current when power is first applied to a capacitive load. Key performance characteristics include a forward voltage drop of 1.0 V typical (at 2 A per leg), low reverse leakage of 5 µA typical, and a maximum junction temperature of 150°C. The device is rated for operation from -55°C to +150°C and is fully lead-free, RoHS compliant, and halogen free. Packaged in tape and reel for high-volume automated SMT assembly, the ESAD92-02R is a cost-effective, space-saving solution for low-power AC-DC rectification in consumer, industrial, and LED lighting applications.

A bridge rectifier is a full-wave rectification circuit that uses four diodes arranged in a bridge configuration to convert alternating current (AC) into pulsating direct current (DC). The ESAD92-02R integrates four such diode chips into a single package with four external terminals: two for the AC input, and two for the DC output (positive and negative). The operation works as follows: during the positive half-cycle of the AC input (when the top AC terminal is positive relative to the bottom AC terminal), two diodes (the top-right and bottom-left diodes in the bridge) are forward-biased and conduct current, while the other two diodes are reverse-biased and block current. Current flows from the positive AC terminal, through the top-right diode to the positive DC output, through the load, back through the negative DC output, through the bottom-left diode, and back to the negative AC terminal. During the negative half-cycle (when the bottom AC terminal is positive and the top is negative), the other two diodes (top-left and bottom-right) conduct. Current now flows from the bottom (now positive) AC terminal, through the bottom-right diode to the positive DC output, through the load, back through the negative DC output, through the top-left diode, and back to the top (now negative) AC terminal. In both half-cycles, the current flows through the load in the same direction — from positive DC to negative DC — resulting in full-wave rectification where both halves of the AC cycle contribute to the DC output. This is more efficient than half-wave rectification (which wastes one half-cycle) and produces a lower-ripple output that is easier to filter with a capacitor. Each individual diode in the bridge is a PN-junction diode fabricated from silicon using a planar process with glass passivation. When forward-biased (anode at higher voltage than cathode), the diode conducts current with a forward voltage drop (VF) of about 1.0 V — this is the voltage required to overcome the PN junction potential barrier. When reverse-biased (cathode at higher voltage than anode), the diode blocks current flow except for a tiny leakage current (microamps). The 200 V reverse voltage rating means each diode can safely block up to 200 V in the reverse direction before breaking down. The bridge configuration inherently means that at any given time, two diodes are conducting in series, so the total forward voltage drop across the bridge (from AC input to DC output) is approximately 2 × VF, or about 2 V at rated current. This VF drop contributes to power loss (heat) in the rectifier — approximately 2W total at 2A for the ESAD92-02R. The glass-passivated junction technology provides stable electrical characteristics over temperature and time, with low reverse leakage and good surge current capability. Overall, the bridge rectifier is a simple but essential component in nearly all AC-input electronic equipment.

The ESAD92-02R is a 4-pin surface-mount bridge rectifier in ESAD/SOP-4/DBS package style.

Package Features:

• Package Style: ESAD / SOP-4 / DBS (surface-mount bridge rectifier package)
• Number of Pins: 4 (two AC inputs, one DC positive, one DC negative)
• Package Dimensions: Approximately 4.8 mm (length) × 4.0 mm (width) × 2.0 mm (height)
• Lead Pitch: Standard SOP pin spacing
• Mounting: Surface mount technology (SMT)
• Polarity Marking: DC+ terminal typically marked with a plus sign or indentation
• Termination Finish: Tin-plated (matte tin), lead-free
• Packaging: Tape and reel (standard for automated SMT pick-and-place)
• Weight: Lightweight (fractions of a gram)

Pinout Notes:

• The two AC input pins are interchangeable (no polarity for AC inputs)
• DC+ and DC- must be correctly connected to the load and filter capacitor
• Reverse connection of DC output would short the bridge through the load
• For thermal performance, use appropriate PCB copper footprint for heat sinking
• Refer to the Littelfuse ESAD92-02R datasheet for exact dimensions, recommended PCB footprint, and thermal considerations

• Switching Power Supplies (SMPS): Used on the primary side of offline flyback, forward, and buck-boost switching power supplies to rectify the AC line voltage into a high-voltage DC bus for the switching converter stage
• AC-DC Adapters & Chargers: Found in wall-mount and desktop AC adapters, mobile phone chargers, laptop power supplies, and battery chargers where compact size and low cost are essential
• LED Drivers & Lighting Power: Used in LED driver circuits and LED lighting power supplies for AC input rectification, feeding the PFC or DC-DC stage that drives the LED array
• Consumer Electronics: Deployed in televisions, monitors, set-top boxes, modems, routers, audio equipment, and small appliances for low- to medium-power AC input rectification
• Industrial Control Power Supplies: Used in auxiliary power supplies for industrial controllers, PLCs, sensors, and instrumentation where the power level is moderate and SMD assembly is preferred
• Battery Chargers: Found in low-power battery chargers for consumer electronics, power tools, and small industrial batteries, providing the full-wave rectification of AC input voltage
• Home Appliances: Used in small home appliances like coffee makers, blenders, and microwave control boards for low-voltage control power supply rectification
• General-Purpose Low-Power Rectification: Serves as a general-purpose full-wave rectifier in any application requiring AC-to-DC conversion at power levels up to approximately 100-150W, where the compact SMD package offers space and cost advantages over through-hole alternatives