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Ultra-Low IQ Buck-Boost Regulator With Bypass

The ISL9122A is a highly integrated non-inverting buck-boost switching regulator that accepts input voltages both above or below the regulated output voltage. It features an extremely low quiescent current consumption of 1300nA in Regulation mode, 120nA in Forced Bypass mode, and 8nA in Shutdown mode. It provides 84% efficiency at 10µA load (VIN = 3.6V, VOUT = 3.3V) and has a peak efficiency greater than 97%. It supports input voltages from 1.8V to 5.5V.


The ISL9122A has automatic bypass functionality for situations in which the input voltage is close to the output voltage, and it automatically transitions between Buck and Boost modes without significant output disturbance. In addition to the automatic bypass functionality, the Forced Bypass power-saving mode can be chosen if voltage regulation is not required. Forced Bypass power saving mode is accessible using the I2C interface bus.


The ISL9122A is capable of delivering up to 500mA of output current (VIN = 3.6V, VOUT = 3.3V) and provides excellent efficiency because of its adaptive frequency hysteretic control architecture.


The ISL9122A is designed for stand-alone applications and supports a default output voltage at Power-On Reset (POR). After POR, the output voltage can be adjusted in the range of 1.8V to 5.375V by using the I2C interface bus. Specific default output voltages are available on request.


The ISL9122A requires only a single EIA 0603 size inductor and two external capacitors. Power supply solution size is minimized by a 1.8mm x 1.0mm WLCSP and is also available in a 3.0mm x 2.0mm 8 Ld plastic DFN.

Key Features

· 1300nA quiescent current

· 84% efficiency at 10µA load

· 97% peak efficiency

· Input voltage range: 1.8V to 5.5V

· Output voltage range: 1.8V to 5.375V

· Output current: up to 500mA (VIN = 3.6V, VOUT = 3.3V)

· Selectable Forced and Auto Bypass power saving modes

· Seamless PWM/PFM and buck/boost transition

· I2C Control and voltage adjustability

· Hysteretic controller

· Small 1.8mm x 1.0mm WLCSP and 3.0mm x 2.0mm 8 Ld DFN packages


Target Applications

· Smart watches and wristband devices

· Wireless earphones

· Internet of Things (IoT) devices

· Water, gas, and oil meters

· Portable medical devices

· Hearing aid devices


For more information click here, or contact your local Braemac representative.

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