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BD9E102FJ (Marking: 9E102) Technical Datasheet & Repair Guide
Operates at a fixed switching frequency, typically between 484 kHz and 656 kHz, which helps balance component size and efficiency.
The evaluation board BD9E102FJ-EVK-001 is priced at approximately $46.43 USD from DigiKey, while production quantities of the IC itself are priced lower, with single-unit pricing around $0.29 from some distributors in high volumes. 9e102 datasheet
The primarily corresponds to the BD9E102FJ , a high-efficiency, single synchronous buck switching regulator manufactured by ROHM Semiconductor . Laser-printed or shortened on circuit boards simply as 9E102 , this integrated circuit (IC) is a current-mode step-down DC/DC converter featuring built-in low on-resistance power MOSFETs. It is widely integrated into modern consumer electronics, telecommunication equipment, and home appliances where minimizing standby power consumption is critical. Core Specifications Overview
: Input signals typically use pins 1–3, while outputs use pins 5–7.
The 9E102 operates as a step-down regulator utilizing integrated low-on-resistance power MOSFETs to convert higher input voltages into stable, low-voltage rails for microprocessors, chipsets, and operational amplifiers. Specification Notes / Conditions 4.5V to 28V Ideal for multi-cell Li-ion laptop batteries or DC jacks Output Current Up to 1.0A Continuous Designed for power distribution rails Switching Frequency ~300 kHz to 1.2 MHz Optimizes efficiency vs. external inductor size Package Type SOP-8 / SOIC-8 Surface-mount package with exposed pad options Architecture Synchronous Buck No external Schottky diode needed for rectification Protection Features OCP, UVLO, TSD Over-Current, Under-Voltage, Thermal Shutdown 9E102 SOP-8 Pinout Configurations I can provide specialized boardview examples or targeted
Enable pin. High enables the IC, Low sets it to standby. 4. Typical Application Circuit
Both the high-side and low-side power MOSFETs are built into the silicon monolithic integrated circuit, reducing the need for external components.
One of the standout features of the BD9E102FJ is its SLLM™ control. This technique optimizes efficiency during light-load conditions by reducing switching losses. In many traditional DC/DC converters, efficiency drops significantly when the output current falls below a certain threshold. The SLLM™ mode automatically adjusts the operating mode to maintain high efficiency across the entire load range, making the device ideal for battery-powered and always-on applications where standby power consumption is critical. The primarily corresponds to the BD9E102FJ , a
The evaluation board BD9E102FJ-EVK-001 provides a complete reference design that outputs 5.0V from an input of 7.2V to 26V. The board is designed to demonstrate the IC’s capabilities, including high efficiency across all load ranges and adjustable loop-response characteristics via the phase compensation circuit.
: Deactivates the IC if internal junction temperatures cross safe thresholds.
Engineers should ensure adequate PCB copper area for heat sinking, particularly when operating at high input voltages and near the full 1A output current.
: Built-in low on-resistance MOSFETs (typically 250 mΩ for the high-side) simplify PCB design by reducing the need for external power components.