XR76203-Q/XR76205-Q/XR76208-Q

3A/5A/8A Synchronous Step Down COT Regulator

exar.com/XR76203-Q/XR76205-Q/XR76208-Q

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©2016-2017 Exar Corporation

General Description

The XR76203-Q, XR76205-Q and XR76208-Q are synchronous step-

down regulators combining the controller, drivers, bootstrap diode and

MOSFETs in a single package for point-of-load supplies well suited for

automotive applications. Qualified per AEC-Q100, the XR76203-Q,

XR76205-Q and XR76208-Q have load current ratings of 3A, 5A and 8A

respectively. A wide 5.5V to 40V input voltage range allows for single sup-

ply operation from 12V battery systems required to withstand load dump,

industry standard 24V ±10%, 18V-36V, and rectified 18VAC and 24VAC

rails.

With a proprietary emulated current mode Constant On-Time (COT) con-

trol scheme, the XR76203-Q, XR76205-Q and XR76208-Q provide

extremely fast line and load transient response using ceramic output

capacitors. They require no loop compensation, simplifying circuit imple-

mentation and reducing overall component count. The control loop also

provides 0.07% load and 0.15% line regulation and maintains constant

operating frequency. A selectable power saving mode allows the user to

operate in discontinuous conduction mode (DCM) at light current loads

thereby significantly increasing the converter efficiency.

A host of protection features, including over-current, over-temperature,

short-circuit and UVLO, helps achieve safe operation under abnormal

operating conditions.

The XR76203/5/8-Q are available in a RoHS-compliant, green/halogen-

free space-saving QFN 5x5mm package.

Typical Application

FEATURES

■

Automotive AEC-Q100 Qualified

❏

Temperature Grade 1: -40°C to 125°C

❏

HBM ESD Class Level 2

❏

CDM ESD Class Level C4B

■

Controller, drivers, bootstrap diode and MOS-

FETs integrated in one package

■

3A, 5A and 8A Step Down Regulators

❏

Wide 5.5V to 40V Input Voltage Range

❏

≥

0.6V Adjustable Output Voltage

■

Proprietary Constant On-Time Control

❏

No Loop Compensation Required

❏

Stable Ceramic Output Capacitor Operation

❏

Programmable 200ns to 2μs On-Time

❏

Constant 100kHz to 800kHz Frequency

■

Selectable CCM or CCM/DCM

❏

CCM/DCM for high efficiency at light-load

❏

CCM for constant frequency at light-load

■

Programmable Hiccup Current Limit with

Thermal Compensation

■

Precision Enable and Power Good flag

■

Programmable Soft-start

■

30-pin 5x5mm QFN package with wettable flanks

APPLICATIONS

■

Automotive Systems

■

Distributed Power Architecture

■

Point-of-Load Converters

■

Power Supply Modules

■

FPGA, DSP, and Processor Supplies

■

Industrial and Military

1

1.

3.260

3.270

3.280

3.290

3.300

3.310

3.320

3.330

3.340

5

10152025303540

PGND

FB

ILIM

SW

BST

XR76208-Q

VIN

EN/MODE

PGOOD

VCC

SS

TON

AGND

Enable/Mode

Power Good

R

L1

R1

R2

XR76205-Q

PVIN

XR76203-Q

Line Regulation