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Renesas ISL9122A Family of Buck-Boost Switching Regulators

Buck-boost DC-DC converter features ultra-low quiescent current for use in wireless devices.

Renesas ISL9122A is a newly-introduced family of flexible buck-boost switching regulators which draw ultra-low quiescent current. This makes them ideal for use in powering sensors, microcontrollers, wireless devices and other system components which normally operate intermittently, with long periods in stand-by mode.

The ISL9122A series’ quiescent current is rated at <1.3µA. In shut-down mode, the buck-boost switching regulators draw just 7nA. Operating over an input-voltage range of 1.8V to 5.5V, the ISL9122A regulators are suitable for use in systems powered by coin cells, lithium-ion rechargeable batteries or multiple alkaline primary batteries in series.

The Renesas ISL9122A switching regulator family implements dynamic voltage scaling in I2C-programmable 25mV steps to optimize system power consumption. In addition, the ISL9122A has the ability to boost output power up to 5.375V, which maximizes the RF transmission capabilities of IoT devices across their battery range.

Switching frequency control is implemented by either pulse-frequency or Pulse-Width Modulation (PWM), depending on the load. In forced PWM mode, the ISL9122A regulator always switches at 2.5MHz, which improves the system’s EMI performance.

Like the ISL9123 buck regulator, the new ISL9122A switching regulators are ideal for powering the Renesas RL78 family of 8-/16-bit ultra-low energy MCUs, the RA family of 32-bit MCUs with Arm® Cortex®-M cores, or the RE family of embedded controllers for wearable devices and energy-harvesting applications.

ISL9122A Features

  • High efficiency:
    - 84% at light load of 10µA
    - 97% peak efficiency at full load
  • Automatic and selectable forced bypass power-saving mode
  • Adjustable output-voltage range: 1.8V to 5.375V in 25mV increments
  • 500mA maximum output current
  • Only requires three external components: one inductor, and input and output capacitors
  • Protection functions:
    - Over-current
    - Short-circuit
    - Over-temperature

ISL9122A Applications

  • Wireless earbuds
  • Fitness bands
  • Smart watches
  • Water or gas meters
  • Portable medical devices
  • Battery-operated smart IoT devices