LDO with Integrated Battery Monitor for Wireless IoT Nodes

The RP124x from Ricoh is a 100mA LDO regulator with a battery monitor (BM) featuring ultra-low quiescent current. The battery monitor has a function which divides the input voltage (VIN) into 1/3 or 1/4.

The battery charge remaining can be monitored by MCU. The buffering output enables directly inputting a signal into the low voltage A/D converter (ADC) with built-in MCU.

Applications for the RP124x are expected to include battery-powered IoT devices, energy-harvesting-powered devices, low power wireless communication modules including: Bluetooth® LE, Zigbee, and LPWA, and low power consumption CPUs, memories, and sensors

The quiescent current of 0.3 µA under no load contributed to smaller system size and longer battery life. The RP124x requires only three external capacitors in a typical application and is suitable for space-constrained applications.

The LDO set output voltage, the divided ratio of BM output voltage, the CE pin function and the auto-discharge function are user-selectable options. The RP124x has an operating temperature range of -40 to +85°C.

Key specifications include:

• LDO Section
  • Input Voltage Range: 1.7V to 5.5V
  • Supply Current: Typ. 0.2µA
  • Output Voltage Accuracy: ±0.8%
  • Output Voltage Range: 1.2V / 1.5V / 1.8V / 2.4V / 2.5V / 2.7V / 2.8 / 3.0V / 3.1V / 3.3V / 3.6V
  • Output Current: 100mA
  • Ceramic Capacitor Compatible: 1.0μF or more
• BM Section
  • Output Voltage: VIN/3 (RP124xxx3x); VIN/4 (RP124xxx4x)
  • Output Voltage Accuracy: ±20mV
  • Supply Current: Typ. 0.1µA
  • Ceramic Capacitor Compatible: 0.1μF to 0.22μF