ISL85402 Ver la hoja de datos (PDF) - Renesas Electronics

Número de pieza

componentes Descripción

Fabricante

ISL85402

2.5A Regulator with Integrated High-Side MOSFET for Synchronous Buck or Boost Buck Converter

Renesas Electronics 

ISL85402

NOT RECOMMENDED FOR NEW DESIGNS

RECOMMENDED REPLACEMENT PART

ISL85403

2.5A Regulator with Integrated High-Side MOSFET for Synchronous Buck or

Boost Buck Converter

DATASHEET

FN7640

Rev 1.00

April 25, 2013

The ISL85402 is a synchronous buck controller with a 125mΩ

high-side MOSFET and low-side driver integrated. The ISL85402

supports a wide input range of 3V to 36V in buck mode. It

supports 2.5A continuous load under conditions of 5V VOUT, VIN

range of 8V to 36V, 500kHz and +105°C ambient temperature

with still air. For any specific application, the actual maximum

output current depends upon the die temperature not exceeding

+125°C with the power dissipated in the IC, which is related to input

voltage, output voltage, duty cycle, switching frequency, board layout

and ambient temperature, etc. Refer to “Output Current” on page 14

for more details.

The ISL85402 has a flexible selection of operation modes of

forced PWM mode and PFM mode. In PFM mode, the

quiescent input current is as low as 180µA (AUXVCC connected

to VOUT). The load boundary between PFM and PWM can be

programmed to cover wide applications.

The low-side driver can be either used to drive an external low-side

MOSFET for a synchronous buck, or left unused for a standard

non-synchronous buck. The low-side driver can also be used to

drive a boost converter as a pre-regulator followed by a buck

controlled by the same IC, which greatly expands the operating

input voltage range down to 2.5V or lower (Refer to “Typical

Application Schematic III - Boost Buck Converter” on page 5).

The ISL85402 offers the most robust current protections. It

uses peak current mode control with cycle-by-cycle current

limiting. It is implemented with frequency foldback under

current limit condition; besides that, the hiccup overcurrent

mode is also implemented to guarantee reliable operations

under harsh short conditions.

The ISL85402 has comprehensive protections against various faults

including overvoltage and over-temperature protections, etc.

Features

• Buck Mode: Input Voltage Range 3V to 36V (Refer to “Input

Voltage” on page 13 for more details)

• Boost Mode Expands Operating Input Voltage Lower Than

2.5V (Refer to “Input Voltage” on page 13 for more details)

• Selectable Forced PWM Mode or PFM Mode

• 300µA IC Quiescent Current (PFM, No Load); 180µA Input

Quiescent Current (PFM, No Load, VOUT Connected to

AUXVCC)

• Less than 3µA Shut Down Input Current (IC Disabled)

• Operational Topologies

- Synchronous Buck

- Non-Synchronous Buck

- Two-Stage Boost Buck

• Programmable Frequency from 200kHz to 2.2MHz and

Frequency Synchronization Capability

• ±1% Tight Voltage Regulation Accuracy

• Reliable Overcurrent Protection

- Temperature Compensated Current Sense

- Cycle-by-Cycle Current Limiting with Frequency Foldback

- Hiccup Mode for Worst Case Short Condition

• 20 Ld 4x4 QFN Package

• Pb-Free (RoHS Compliant)

Applications

• General Purpose

• 24V Bus Power

• Battery Power

• Point of Load

• Embedded Processor and I/O Supplies

PGOOD

EN

VIN

VIN

MODE

SYNC

AUXVCC

BOOT

VCC

ILIMIT

SS

ISL85402 PHASE

LGATE

PGND

EXT_BOOST

FS

SGND

FB

COMP

FIGURE 1. TYPICAL APPLICATION

VOUT

100

95

6V VIN

90

85

12V VIN

80

75

36V VIN

70

24V VIN

65

60

55

50

0.1m

1m

10m

100m

1.0 2.5

LOAD CURRENT (A)

FIGURE 2. EFFICIENCY, SYNCHRONOUS BUCK, PFM MODE,

VOUT 5V, TA = +25°C

FN7640 Rev 1.00

April 25, 2013

Page 1 of 22

Share Link: