The ISL6341, ISL6341A, ISL6341B makes simple work out of implementing a complete control and protection scheme for a DC/DC stepdown converter driving N-Channel MOSFETs in a synchronous buck topology. Since it can work with either 5V or 12V supplies, this one IC can be used in a wide variety of applications within a system. The ISL6341, ISL6341A, ISL6341B integrates the control, gate drivers, output adjustment, monitoring and protection functions into a single 10 Ld 3x3 Thin DFN package.

The ISL6341, ISL6341A, ISL6341B provides single feedback loop, voltage-mode control with fast transient response. The output voltage can be precisely regulated to as low as 0.8V, with a maximum tolerance of ±0.8% over temperature and line voltage variations. A fixed frequency oscillator (300kHz for ISL6341; 600kHz for ISL6341A, ISL6341B) reduces design complexity, while balancing typical application cost and efficiency. The PWM duty cycles range from 0% to around 85% at 300kHz (75% at 600kHz). The frequency, duty cycle and OCP are the only differences among the ISL6341, ISL6341A, ISL6341B. See Table 1 for a summary.

Protection from overcurrent conditions is provided by monitoring the r_DS(ON) of the lower MOSFET to inhibit PWM operation appropriately (the ISL6341, ISL6341B are slightly different from the ISL6341A; see “Overcurrent Protection (OCP)” on page 7 for details). This approach simplifies the implementation and improves efficiency by eliminating the need for a current sense resistor. The output voltage is also monitored for undervoltage and overvoltage protection, in addition to monitoring for a PGOOD output.

• Operates from +4.5V to 14.4V Supply Voltage (for bias)
  • 1.5V to 12V V_IN Input Range (up to 20V is possible with restrictions; see “Input Voltage Considerations”)
  • 0.8V to ~V_IN Output Range (duty cycle limited)
  • Integrated Gate Drivers; LGATE Uses VCC (5V to 12V); UGATE Uses External Boot Diode to 5V to 12V
  • 0.8V Internal Reference; ±0.8% Tolerance
• Simple Single-Loop Control Design
  • Traditional Dual Edge Modulator
  • Voltage-Mode PWM Control
  • Drives N-Channel MOSFETs
• Fast Transient Response
  • High-Bandwidth Error Amplifier
  • 0% to 85% Max Duty Cycle for ISL6341 (75% for ISL6341A, ISL6341B)
• Lossless, Programmable Overcurrent Protection
  • Uses Lower MOSFET’s r_DS(ON)
• Output Voltage Monitoring
  • Undervoltage and Overvoltage Shutdown
  • PGOOD Output
• Small Converter Size in a 10 Ld 3x3 Thin DFN Package
  • 300kHz or 600kHz Fixed Frequency Oscillator
  • Fixed Internal Soft-Start, Capable into a Pre-biased Load
  • Enable/Shutdown Function on COMP/EN Pin
• Pb-Free (RoHS Compliant)

• Power Supplies for Microprocessors or Peripherals
  • PCs, Servers, Memory Supplies
  • DSP and Core Communications Processor Supplies
• Subsystem Power Supplies
  • PCI, AGP; Graphics Cards; Digital TV
  • SSTL-2 and DDR/DDR2/DDR3 SDRAM Bus Termination Supply
• Cable Modems, Set-Top Boxes, and DSL Modems
• Industrial Power Supplies; General Purpose Supplies
• 5V or 12V-Input DC/DC Regulators
• Low-Voltage Distributed Power Supplies; Point of Load