Description

The RJ2421ABOPO is from the RS5RJ series of step-up DC/DC converter ICs that are designed by CMOS process and comes with a voltage regulator and a voltage detector. These ICs are operating-voltage-fixed type regulators that consist of a VFM DC/DC converter, a linear regulator, and a voltage detector. When the input voltage is high, they function as linear regulators, and when the input voltage is low, they work as step-up DC/DC converters along with linear regulators. The ICs use an inductor, a diode, and a capacitor as external parts. With the built-in voltage detector, the potential of the output voltage of the DC/DC converters can be monitored. Furthermore, the RJ2421ABOPO is perfect for battery-powered and hand-held instruments as its internal circuits can be switched off by chip enable function to minimize the standby current.

Specifications and features

• Low supply current: TYP. 15µA (RS5RJ3624A: VIN=3.0V, at no load)
• Standby mode: Istandby=MAX. 1.0µA (RS5RJ××××A) / Istandby=MAX. 10.0µA (RS5RJ××××B)
• Low voltage operation possible: Operating Voltage VIN=1.2V to 10V
• High output voltage accuracy: Fixed Output Voltage accuracy±2.5%
• High detector threshold accuracy: ±2.5%
• Output voltage can be set at user's request (refer to Selection Guide)
• Voltage close to the battery's voltage can be output because these ICs are of a step-up / step-down type (Ex. a fixed voltage of 3V can be output by a 3V battery)
• Built-in protection circuits for Lx driver
• Pin for external driver is equipped, and a large current output can be obtained
• Small package: 8pin SOP

Application Scenarios

• Power source for cameras, camcorders, and hand-held audio equipment
• Power source for small OA apparatus such as note type personal computers and word processors
• Power source for hand-held communication appliances such as pagers, cordless telephones, and cellular phones

Comparison

• The RJ2421ABOPO is a low supply current and low voltage operation compatible chip designed for battery-powered and hand-held instruments
• It is a voltage detector-equipped IC, making it easy to monitor the potential of the output voltage of the DC/DC converters
• The IC includes built-in protection circuits for Lx driver and an external driver pin present, which helps in achieving large current output
• The small package of 8pin SOP makes it simple to install and carry around

• The fixed output voltage accuracy of RJ2421ABOPO is ±2.5%, which could be a limitation in some cases requiring higher accuracy