ROHM’s New LDO Regulators with 500mA Output Current Achieving Stable Operation Even with Ultra-small Capacitors to Expand Design Flexibility for High-current Applications

　　ROHM has developed the “BD9xxN5 Series” of LDO regulator ICs with 500mA output current, featuring its proprietary ultra-stable control technology “Nano Cap™”. This series comprises 18 products designed for 12V/24V primary power supply applications used in automotive equipment, industrial equipment, and communication infrastructure.

　　In recent years, electronic devices have demanded higher density in smaller form factors at the same time. To meet this demand and achieve space savings and design flexibility, power supply ICs must be capable of stable operation even with small-capacity capacitors. However, achieving such performance with output capacitors of 1µF or less has been technically difficult.

　　To address this challenge, ROHM developed the “BD9xxN1 Series” LDO regulator (150mA output current) in 2022, incorporating its proprietary ultra-stable control technology, “Nano Cap™”. This innovation enables stable operation with output capacitors as small as 100nF, earning widespread adoption across numerous applications.

　　The newly developed BD9xxN5 Series builds on the success of the BD9xxN1 Series by increasing the output current to 500mA – more than three times higher than before – significantly broadening its suitability for applications requiring higher power. In addition, very low output voltage ripple of approximately 250mV (with load current variation of 1mA to 500mA within 1µs) is achieved with a small output capacitance of just 470nF (typical). Beyond standard small MLCCs (multi-layer ceramic capacitors) in the range of several µF and large-capacity electrolytic capacitors, it also supports ultra-small MLCCs, such as the 0603M size (0.6mm × 0.3mm), with capacities below 1µF – where stability was previously difficult to achieve. This contributes to space saving as well as greater flexibility in component selection.

　　Furthermore, high-precision SPICE models, “ROHM Real Model” are provided for accurate simulation and can be downloaded from the ROHM official website.

　　SPICE Models: BD900N5xxx-C BD933N5xxxx-C BD950N5xxxx-C

　　ROHM will continue to contribute to the high performance, miniaturization, and high reliability of electronic devices by further expanding its Nano Cap™ technology-equipped LDO series.

　　Application Examples

　　Automotive Equipment

　　● Powertrain system power supplies for fuel injection systems (FI) and tire pressure monitoring systems (TPMS)● Body system power supplies for body control modules (BCM)● Infotainment system power supplies for clusters ad head-up displays (HUD), etc.Industrial Equipment

　　● Power supplies for controllers like Programmable Logic Controllers (PLC), Remote Terminal Units (RTU), and industrial gateways● High-precision LDOs for analog loads and sensors measuring temperature, pressure, flow rate, etc.● Power supplies for monitoring and control panels in disaster prevention systems, access control systems and building automation.● Standby power supplies for Human-Machine Interfaces (HMI) and panel equipment, etc.Consumer Electronics

　　● Power supplies for control boards in refrigerators, dishwashers, air conditioners, etc.● Power supplies for home appliances like thermostats and doorbells● Power supplies for constant power applications in home security and network equipment, etc.

　　What is Nano Cap™ Technology?

　　Nano Cap™ refers to ultra-stable control technology achieved by combining advanced analog expertise covering circuit design, processes, and layout utilizing ROHM’s vertically integrated production system. Stable control eliminates the problem of unstable operation related to capacitors in analog circuits, contributing to a reduction in design resources for a wide range of applications in automotive, industrial equipment, consumer, and other fields.

　　Terminology

　　Primary

　　In a power supply circuit, the side in charge of 1st stage conversion from a power source such as a battery is called the primary and the side responsible for 2nd stage conversion is referred to as the secondary.

　　LDO Regulator (Low Drop Out Regulator / Low Saturation Regulator)

　　A type of power supply IC that converts between two different DC voltage levels. Falls under the category of linear regulator (where the input/output voltages operate linearly) characterized by a small input-output voltage difference. Compared to DC-DC converter ICs (switching regulators), LDOs feature a simpler circuit configuration and lower noise.

　　ROHM Real Model

　　A high-accuracy simulation model that make it possible to also achieve a perfect match between the actual IC and simulation values utilizing ROHM’s proprietary model-based technology.