ISL6420BMAEP Datasheet, PDF (1/3 Pages) Intersil Corporation – Enhanced Product (EP) Advanced Single Synchronous Buck Pulse-Width Modulation (PWM) Controller

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Data Sheet
ISL6420BMAEP
October 29, 2007
FN6574.0
Enhanced Product (EP) Advanced Single
Synchronous Buck Pulse-Width
Modulation (PWM) Controller
The ISL6420BMAEP simplifies the implementation of a
complete control and protection scheme for a high-
performance DC/DC buck converter. It is designed to drive
N-Channel MOSFETs in a synchronous rectified buck
topology, the ISL6420BMAEP integrates control, output
adjustment, monitoring and protection functions into a single
package. Additionally, the IC features an external reference
voltage tracking mode for externally referenced buck
converter applications and DDR termination supplies, as well
as a voltage margining mode for system testing in
networking DC/DC converter applications.
The ISL6420BMAEP provides simple, single feedback loop,
voltage mode control with fast transient response. The
output voltage of the converter can be precisely regulated to
as low as 0.6V, with a maximum tolerance of ±2.0% over
temperature and line voltage variations.
The operating frequency is fully adjustable from 100kHz to
1.4MHz. High frequency operation offers cost and space
savings.
The error amplifier features a 15MHz gain-bandwidth
product and 6V/µs slew rate that enables high converter
bandwidth for fast transient response. The PWM duty cycle
ranges from 0% to 100% in transient conditions. Selecting
the capacitor value from the ENSS pin to ground sets a fully
adjustable PWM soft-start. Pulling the ENSS pin LOW
disables the controller.
The ISL6420BMAEP monitors the output voltage and
generates a PGOOD (power good) signal when soft-start
sequence is complete 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
monitoring the r_DS(ON) of the upper MOSFET to inhibit the
PWM operation appropriately. This approach simplifies the
implementation and improves efficiency by eliminating the
need for a current sensing resistor.
Device Information
The specifications for an Enhanced Product (EP) device are
defined in a Vendor Item Drawing (VID), which is controlled
by the Defense Supply Center in Columbus (DSCC). “Hot-
links” to the applicable VID and other supporting application
information are provided on our website.
Features
• Specifications per DSCC VID V62/07640
• Full Mil-Temp Electrical Performance from -55°C to +125°C
• Controlled Baseline with One Wafer Fabrication Site and
One Assembly/Test Site
• Full Homogeneous Lot Processing in Wafer Fab
• No Combination of Wafer Fabrication Lots in Assembly
• Full Traceability Through Assembly and Test by
Date/Trace Code Assignment
• Enhanced Process Change Notification
• Enhanced Obsolescence Management
• Eliminates Need for Up-Screening a COTS Component
• Operates from 4.5V thru 5.5V and 5.6V thru 28V Inputs
• Excellent Output Voltage Regulation
- 0.6V Internal Reference
- ±2.0% Reference Accuracy Over Line and Temperature
• Resistor-Selectable Switching Frequency
- 100kHz to 1.4MHz
• Voltage Margining and External Reference Tracking
Modes
• Output Can Sink or Source Current
• Lossless, Programmable Overcurrent Protection
- Uses Upper MOSFET’s r_DS(ON)
• Programmable Soft-Start
• Drives N-Channel MOSFETs
• Simple Single-Loop Control Design
- Voltage-Mode PWM Control
• Fast Transient Response
- High-Bandwidth Error Amplifier
- Full 0% to 100% Duty Cycle
• Extensive Circuit Protection Functions
- PGOOD, Overvoltage, Overcurrent, Shutdown
• Diode Emulation during Startup for Pre-Biased Load
Applications
Applications
• Power Supplies for Microprocessors/ASICs
- DSP and Core Processors
- DDR SDRAM Bus Termination
• Distributed Power Systems
• Externally Referenced Buck Converters
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CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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