GND

SW

BOOT

VIN

RT/CLK

SS

RST

FB1

EN2

COMP

TPS65321-Q1

EN1

PowerPAD

LDO_OUT

VIN_LDO

FB2

1.1 V to 5.5 V,

280 mA

1.1 V to 20 V,

3.2 A

LDO

Regulator

Control

Buck

Regulator

Control

Supply

Supply

Copyright © 2017, Texas Instruments Incorporated

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An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,

intellectual property matters and other important disclaimers. PRODUCTION DATA.

TPS65321A-Q1

SLVSE55 – NOVEMBER 2017

TPS65321A-Q1 36-V Step-Down Converter With Eco-mode™ and LDO Regulator

1

1 Features

1

•

Qualified for Automotive Applications

•

AEC-Q100 Qualified with the Following Results:

–

Device Temperature Grade 1: –40°C to

+125°C Ambient Operating Temperature

–

Device HBM ESD Classification Level 2

–

Device CDM ESD Classification Level C4B

•

One High-VIN Step-Down DC-DC Converter

–

Input Range of 3.6 V to 36 V

–

250-mΩ High-Side MOSFET

–

Maximum Load Current 3.2 A, Output

Adjustable 1.1 V to 20 V

–

Adjustable Switching Frequency 100 kHz to

2.5 MHz

–

Synchronizes to External Clock

–

High Efficiency at Light Loads With Pulse-

Skipping Eco-mode™ Control Scheme

–

Maximum 140-µA Operating Quiescent

Current

–

Reset Output-Pin (Active Low, Open-Drain)

•

One High-VIN Low-Dropout (LDO) Voltage

Regulator

–

Input Range of 3 V to 36 V

–

280-mA Current Capability With Typical 35-µA

Quiescent Current in No-Load Condition

–

Low-Dropout Voltage of 300 mV at

•

Overcurrent Protection for Both Regulators

•

Overtemperature Protection

•

14-Pin HTSSOP Package With PowerPAD™

Integrated Circuit Package

2 Applications

•

Automotive Infotainment and Cluster

•

Advanced Driver Assistance System (ADAS)

•

Automotive Telematics, eCall

3 Description

The TPS65321A-Q1 device is a combination of a

high-VIN DC-DC step-down converter, referred to as

the buck regulator, with an adjustable switch-mode

frequency from 100-kHz to 2.5-MHz, and a high-VIN

280-mA low-dropout (LDO) regulator. The input range

is 3.6 V to 36 V for the buck regulator, and 3 V to

36 V for the LDO regulator. The buck regulator has

an integrated high-side MOSFET with an active-low,

open-drain power-good output-pin (nRST). The LDO

regulator features a low-input supply current of 45-μA

typical in no-load, also has an integrated MOSFET.

Low-voltage tracking feature enables TPS65321A-Q1

to track the input supply during cold-crank conditions.

The buck regulator provides a flexible design to fit

system needs. The external loop compensation circuit

allows for optimization of the converter response for

the appropriate operating conditions. A low-ripple

pulse-skip mode reduces the no-load input-supply

current to maximum 140 μA.

The device has built-in protection features such as

soft start, current-limit, thermal sensing and shutdown

due to excessive power dissipation. Furthermore, the

device has an internal undervoltage-lockout (UVLO)

function that turns off the device when the supply

voltage is too low.

Device Information(1)

PART NUMBER

PACKAGE

BODY SIZE (NOM)

TPS65321A-Q1

HTSSOP (14)

5.00 mm × 4.40 mm

(1) For all available packages, see the orderable addendum at

the end of the data sheet.

Typical Application Schematic

Buck Efficiency Versus Output Current