ISL6420B Advanced Single Synchronous Buck Pulse-Width Modulation (PWM) Controller

VIN (min) (V)	4.5
VIN (max) (V)	28
VOUT (min) (V)	0.6
VOUT (max) (V)	VIN-0.5V
IOUT (max) (A)	20
VBIAS (V)	5

The ISL6420B 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 ISL6420B 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 ISL6420B 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.

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 ISL6420B 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 rDS(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.

ISL6420B 特点

Operates From:
- 4.5V to 5.5V Input
- 5.5V to 28V Input
0.6V Internal Reference Voltage
- ±2.0% Reference Accuracy
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 rDS(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
Offered in 20 Ld QFN and QSOP Packages
QFN (4x4) Package
- QFN compliant to JEDEC PUB95 MO-220 QFN -Quad Flat No Leads - Product Outline
- QFN Near Chip Scale Package Footprint; Improves PCB Efficiency, Thinner in Profile
Pb-Free (RoHS Compliant)

ISL6420B 应用

Power Supplies for Microprocessors/ASICs
- Embedded Controllers
- DSP and Core Processors
- DDR SDRAM Bus Termination
Ethernet Routers and Switchers
High-Power DC/DC Regulators
Distributed DC/DC Power Architecture
Personal Computer Peripherals
Externally Referenced Buck Converters

ISL6420B 芯片订购指南

芯片型号	产品状态	温度范围	封装尺寸图	潮湿敏感度等级MSL	美元价格US $
ISL6420BEVAL2Z	量产		评估板	N/A
ISL6420BIAZ	量产	工业级	20 Ld QSOP	2
ISL6420BIAZ-TK	量产	工业级	20 Ld QSOP T+R	2
ISL6420BIRZ	量产	工业级	20 Ld QFN	2
ISL6420BIRZ-TK	量产	工业级	20 Ld QFN T+R	2