ISL9440B
Triple Step-Down PWM and Single Linear Controller with Programmable Soft-Start

Key Features

• Three Integrated Synchronous Buck PWM Controllers
• Internal Bootstrap Diodes
• Internal Compensation
• Independent Control for each Regulator and Programmable Output Voltages; Independent Enable/Shutdown/Soft-start
• Fixed Switching Frequency: 300kHz(B), 600kHz(C)
• Adaptive Shoot-Through Protection on all Synchronous Buck Controllers
• Pre-biased Output Start-up Capability
• Out-of-Phase Switching to Reduce Input Capacitance (0°/180°/0°)
• No External Current Sense Resistor
• Uses Lower MOSFET's r_DS(ON)
• Current Mode Controller with Voltage Feed-Forward
• Complete Protection
• Overcurrent, Overvoltage, Undervoltage Lockout, Over-Temperature
• Cycle-by-Cycle Current Limiting
• Wide Input Voltage Range
• Input Rail Powers VIN Pin: 5.6V to 24V
• Input Rail Powers VCC_5V Pin (VIN tied to VCC_5V, for 5V input applications): 4.5V to 5.6V
• Early Warning on Input Voltage Failure
• Integrated Reset Function
• Pb-Free (RoHS Compliant)

Description

The ISL9440B and ISL9440C are quad-output synchronous buck controllers that integrate three PWM controllers and one low drop-out linear regulator controller, which are full featured and designed to provide multi-rail power for use in products such as cable and satellite
set-top boxes, VoIP gateways, cable modems, and other home connectivity products as well as a variety of industrial and general purpose applications. Each output is adjustable down to 0.8V. The PWMs are synchronized at 180° out-of-phase thus, reducing the RMS input current and ripple voltage.

The ISL9440B and ISL9440C offer programmable soft-start, independent enable inputs for ease of supply rail sequencing, and integrated UV/OV/OC/OT protections in a space conscious 5mmx5mm QFN package. An early warning function is offered to output a logic signal to warn the system to back up data when input voltage falls below a certain level.

The ISL9440B and ISL9440C utilize internal loop compensation to keep minimum peripheral components for compact design and a low total solution cost. These devices are implemented with current mode control with feed-forward to cover various applications even with fixed internal compensations.

Applications

• Satellite and Cable Set-Top Boxes
• Cable Modems
• VoX Gateway Devices
• NAS/SAN Devices
• ATX Power Supply