Intersil's Latest Dual Synchronous Buck Regulators Provide Design Flexibility, Deliver 95% Peak Efficiency to Maximize Battery Life

The ISL8033/A and ISL8036/A are dual output step-down DC/DC regulators that can deliver up to 3A continuous output current per channel. The ISL8022 provides similar functionality for lower current applications, delivering up to 2A/1.7A continuous output current on its two channels. All three families of devices feature a peak current mode, fixed frequency control architecture that enables ultra-low duty cycle operation, excellent loop stability and fast load transient response. The fast load transient response reduces required output capacitance and enables a smaller total solution size compared with traditional voltage mode control architectures. The two channels in the ISL8033/A, ISL8036/A and ISL8022 switch 180 degrees out-of-phase, reducing the input ripple current and filter requirements. Internal loop compensation further reduces the external component count and cost.

The ISL8033 and ISL8036 offer a fixed switching frequency of 1MHz, while the ISL8033A and ISL8036A switch at 2.5MHz to significantly reduce the overall DC/DC converter size. The ISL8033 and ISL8036 can also be synchronized to an external clock of up to 6MHz, further reducing the overall solution size and eliminating beat frequencies in multi-switcher designs. Independent enable and PGOOD pins for both channels provide complete start-up control and inherent output monitoring, eliminating the need for discrete sequencers and voltage monitors.


In addition to sourcing 3A independently, both channels in the ISL8036/A can be paralleled to create a single 6A output in current sharing mode for higher power applications. The ISL8033/A provides the user the flexibility to program the over-current trip threshold for each channel, thereby allowing the IC to be configured in either a 3A/2A or a 2A/2A configuration to support various load profiles. The internal power MOSFETs are optimized to support output voltages as low as 0.8V while providing high efficiency.

The ISL8022 offers selectable forced-PWM mode or automatic PWM/PFM mode to optimize battery life in portable and handheld applications. The low 40uA quiescent current makes the ISL8022 ideal for battery powered and other green power applications.

The ISL8022 operates at a fixed switching frequency of 2.25MHz, offering designers the ability to use small, cost-effective inductors and capacitors. Similar to the ISL8033/36, the ISL8022 can also be synchronized to an external clock up to 8MHz, further reducing the overall solution size and eliminating beat frequencies in multi-switcher designs. The internal power MOSFETs are optimized to support output voltages as low as 0.6V while providing high efficiency.