Intersil Switching regulator delivers a 98% efficiency

Intersil Corporation announced the ISL9120, a buck-boost switching regulator that enables efficient power management of system power supplies and peripherals such as Wi-Fi, Bluetooth, memory cards or LCD modules. Its adaptive current limit PFM architecture delivers industry-leading efficiency up to 98%, while providing smooth transitions from buck-to-boost to prevent glitches in applications where light load efficiency and fast transient response are critical. An ultra-small form factor makes the ISL9120 ideal for the connected devices making up the Internet of Things (IoT) including wearables, smartphones, smart thermostats and point-of-sale devices that run on single-cell Li-ion or Li-polymer batteries, or 2-cell alkaline, NiCd or NiMH batteries.

With the pervasiveness of mobile devices and growing popularity of wearables, power designers are challenged to balance cost, form factor and power efficiency. Typical power solutions for wearables use three DC-DC regulators and 3-5 LDOs, which takes up valuable board space. LDOs also lack the high efficiency and reliability of a buck-boost regulator, sacrificing performance as well. For example, when LDOs are used to power peripherals in a system running on a Li-ion battery with the Vout near 3.3V, a large burst current from the applications processor can cause the Vin to droop below the LDO regulation voltage, causing a memory reset or application shutdown. The ISL9120 buck-boost switching regulator eliminates this problem by addressing a wider Vin range and providing boost to avoid low voltage glitches that can cause a battery brownout when the Vin droops below the output voltage. Requiring only a single inductor and available in a small 1.41mm x 1.41mm package, designers no longer have to compromise efficiency or form factor.

The ISL9120 offers designers the flexibility to cover a variety of design needs by operating from a Vin of 1.8V to 5.5V and an adjustable output voltage from 1V to 5.2V. Its adaptive PFM operation with forced bypass mode and 2A switches support both low load and high load currents with high efficiency, ensuring longer battery life and less heat buildup. The regulator also delivers 800mA current with 2.5V input and 3.3V output. During system stay alive conditions when regulation is not required, the ISL9120 goes into forced bypass mode, which reduces power consumption to a miniscule quiescent current of less than 0.5uA.

“Intersil’s innovative adaptive PFM architecture addresses the most critical low power design requirements for wearables and other 4G/Wi-Fi-enabled portable products functioning as IoT connected nodes,” said Andrew Cowell, senior vice president of Mobile Power Products at Intersil. “The new ISL9120 regulator’s small size, industry leading efficiency, smooth transition between buck and boost modes and rapid transient response to a large load step is extremely attractive to customers.”

Key features and specifications

• Ultra high efficiency up to 98% reduces power drain and heat buildup
• Accepts a wide input voltage range from 1.8V to 5.5V, works with multiple battery topologies
• Large adjustable output voltage range from 1V to 5.2V for use with multiple power rails
• Output current up to 800mA (Vin = 2.5V, Vout = 3.3V)
• 2A switches supports both high and light load currents with high efficiency
• Ultra-small footprint with 1.41mm x 1.41mm package saves board space, requires only a single inductor
• Quiescent current of 41uA maximizes light load efficiency for low power consumption
• Automatic and selectable forced bypass power saving mode reduces quiescent current to less than 0.5uA
• Full protection for under-voltage, short-circuit and over-temperature

Pricing and Availability

The ISL9120 buck-boost regulator is available in 9-bump WLCSP and QFN packages, and is priced at $0.72 USD in 1k quantities. Two ISL9120 evaluation boards allow designers to evaluate device features and performance: The ISL9120IIN-EVZ (3.3Vout) is priced at $74.45 USD and the ISL9120IIA-EVZ (adjustable Vout) is $73.35 USD.