PWM Controller/Driver IC

The new Endura ISL6420 from Intersil Corp. is a single-phase synchronous-buck pulse-width modulation (PWM) controller with integrated MOSFET drivers. This high-performance IC integrates control, protection, monitoring and output adjustment all in one very small 4-mm × 4-mm quad flat no-lead (QFN) package. The ISL6420 is suitable for a range of applications, including but not limited to core power for FPGAs, ASICs, DSPs, embedded controllers and microprocessors, as well as for Ethernet routers and switchers, distributed dc-dc conversion and tracking external reference buck converters. In every application, the ISL6420 provides designers with precision, flexibility and reliability along with space and cost savings.

Simple, single-feedback loop voltage mode control of the ISL6420 provides fast transient response. The output voltage can be precisely regulated to as low as 0.6 V, with a maximum tolerance of ±1% over temperature and line voltage variations. The switching frequency is fully adjustable from 100 kHz to 1.4 MHz, providing a wide range of design discretion. The high frequency end of the range allows designers to realize space and cost savings because smaller and fewer passive filter components are needed.

The ISL6420 includes a high-performance error amplifier that features a 15-MHz gain bandwidth product (GBP) and a 6-V/µs slew rate that enables high converter bandwidth for fast transient response and a cleaner dc output.

The PWM duty cycle is not limited and can cover the entire 0% to 100% range as needed. Soft-start can be optimized as desired by selecting the capacitor value from the enable soft-start (EN/SS) pin to ground. Switching the EN/SS pin to ground disables the controller.

The ISL6420 monitors the output voltage and generates a power-good (PGOOD) signal when the soft-start sequence has completed and the output is within regulation. A built-in overvoltage protection circuit prevents the output voltage from going above typically 115% of the set point. Protection from overcurrent conditions is provided by making use of the R_DS(ON); of the upper MOSFET, saving the cost of an external current-sense resistor.

For more information, visit www.intersil.com.