BD90521EFV-C - Documentation

The BD90521EFV-C is a synchronous step-down converter which operates in current mode. It can operate with maximum frequency of 2.4 MHz, and can downsize external parts such as inductor. It can supply a maximum output current of 2A with built-in Pch and Nch output MOSFET. Output voltage and oscillation frequency can be adjusted by external resistors and can also be synchronized with an external clock.

White Paper

Cutting-Edge Web Simulation Tool “ROHM Solution Simulator” Capable of Complete Circuit Verification of Power Devices and Driver ICs
 
In recent years, the advancing digitization of applications is expanding the number and role of electronic circuits, resulting in a considerable amount of man-hours spent on circuit design, from component selection during application development to board design and evaluation. This document discribes the solution for solving customer issues for each design flow with ROHM's support and tools.

Application Note

Calculation of Power Dissipation in Switching Circuit
 
This application note describes how to calculate the power dissipation that occurs in a SiC MOSFET in a switching circuit with the SiC MOSFET during switching operations.
Considering Input Filter to Reduce Conducted Emissions by DCDC Converter
 
This application note is about designing input filter which is attributed to reduce level of conducted emissions to an acceptable value for DC-DC converter.
Notes for Temperature Measurement Using Thermocouples
 
This application note explains cautions regarding the temperature measurement. The content of this application note is generally applicable, irrespective of the types of semiconductor devices.
Two-Resistor Model for Thermal Simulation
 
This application note explains the two-resistor model, which is the simplest model among thermal models used in thermal simulations. The thermal simulations mentioned three-dimensional model thermal conduction and thermal fluid analysis tools.
Notes for Temperature Measurement Using Forward Voltage of PN Junction
 
This application note explains cautions regarding the temperature measurement Using Forward Voltage of PN Junction. The content of this application note is generally applicable, irrespective of the types of semiconductor devices.
Considering Polarity of Power Inductor to Reduce Radiated Emission of DC-DC converter
 
This application note is about radiated emission caused by a power inductor in a DC-DC converter dependent to the polarity of a coil.
Method for Monitoring Switching Waveform
 
This application note explains how to correctly monitor the switching waveforms of the power device element such as switching power supply or a motor drive circuit.
Phase Compensation Design for Current Mode Buck Converter
 
This application note explains the method used by ROHM for designing the phase compensation for current mode buck converters.
Suppression Method of Switching Noise Using Linear Regulator and Low Pass Filter
 
This application note describes the method and result of the ripple and switching noise suppression using a linear regulator and a low pass filter.
PCB Layout Techniques of Buck Converter
 
Major problems that arise from in appropriate layout may cause increase in noise superposed by output and switching signal, the deterioration of regulator, and also lack of stability...
Bootstrap Circuit in the Buck Converter
 
This application note explains the step-up circuit using a bootstrap capacitor. In buck converters, this circuit is used when the highside switch is the N-ch MOSFET.
Method for Determining Constants of
 
This application note explains the procedures for determining the constants of peripheral parts of a buck DC/DC converter.
Power Supply Sequence Circuit with General Purpose Power Supply IC
 
This application note proposes a circuit that accomplishes the power supply sequence without using any dedicated power supply sequence IC, by using general purpose power supply ICs.
Measurement Method for Phase Margin with Frequency Response Analyzer (FRA)
 
This application note introduces a method for easily measuring the phase margin with a Frequency Response Analyzer (FRA) made by NF Corporation.
Usage of SPICE Macromodel for DC/DC
 
This application note explains how to install SPICE macromodels and how the circuit symbols are configured.
Snubber Circuit for Buck Converter IC
 
In buck converter ICs, many high-frequency noises are generated at switch nodes. A snubber circuit provides one way of eliminating such harmonic noise. This application note explains how to set up the RC snubber circuits.
Efficiency of Buck Converter
 
This application note explains power loss factors and methods for calculating them. It also explains how the relative importance of power loss factors depends on the specifications of the switching power source.
Calculation of Power Loss (Synchronous)
 
This application note describes how to obtain the power loss required to calculate the temperature of a semiconductor device. Temperature control is important to ensuring product reliability.
Inductor Calculation for Buck converter IC
 
This application note covers the steps required in choosing the inductor and to calculate the value used in buck regulator IC circuits.
Considerations for Power Inductors Used for Buck Converters
 
This application note explains the features and things to consider when shopping for power inductors.
Capacitor Calculation for Buck converter IC
 
This application note explains the calculation of external capacitor value for buck converter IC circuit.
The Important Points of Multi-layer Ceramic Capacitor Used in Buck Converter circuit
 
Using unmatched MLCC may not obtain required target characteristics for power supply circuit and may cause abnormal operation. This application note explains the important points while using MLCC.
Resistor Value Table to set Output Voltage of Buck Converter IC
 
This Application Note offers reference table to easily set resistor values for output voltage with various internal reference voltages VREF.
Thermal Resistance
 
The definition and how to use thermal resistance and thermal characterization parameter of packages for ROHM’s integrated circuit are described in this application note.
Part Explanation
 
For ICs