General Description

The RT6264A/B is a simple, easy-to-use, 4A

synchronous step-down DC-DC converter with an input

supply voltage range of 4.5V to 18V. The device

possesses an accurate 0.765V reference voltage and

integrates low RDS(ON) power MOSFETs to achieve

high efficiency.

The RT6264A/B adopts Advanced Constant On-Time

ACOT? ) control architecture to provide an ultrafast

transient response with few external components and

to operate in nearly constant switching frequency over

the line, load, and output voltage range. The RT6264A

operates in automatic PSM that maintains high

efficiency during light load operation. The RT6264B

operates in Forced PWM that helps meet tight voltage

regulation accuracy requirements.

The RT6264A/B senses both FETs current for a robust

over-current protection. The device features

cycle-by-cycle current limit protection to prevent the

device from the catastrophic damage in output short

circuit, over-current or inductor saturation conditions. A

built-in soft-start function prevents inrush current during

start-up. The device also includes input under-voltage

lockout, output under-voltage protection, and

over-temperature protection (thermal shutdown) to

provide safe and smooth operation in all operating

conditions.

特性 Features

? 4A Converter Integrated 66m? and 36m? FETs

? Input Supply Voltage Range : 4.5V to 18V

? Output Voltage Range : 0.765V to 7V

? Advanced Constant On-Time (ACOT? ) Control

? Ultrafast Transient Response

? Optimized for Low-ESR Ceramic Output

Capacitors

? High Accuracy Feedback Reference Voltage :

Typ. ?1

? Optional for Operation Modes :

? RT6264A : Power Saving Mode (PSM)

? RT6264B : Forced PWM Mode

? Fixed Switching Frequency : 650kHz

? Enable Control and Internally Fixed Soft-Start

with typ. 1ms

? Input Under-Voltage Lockout (UVLO)

? Protection Function

? Output Under-Voltage Protection (UVP) with

Hiccup Mode

? High- / Low-side MOSFET OCP and OTP

Function

? RoHS Compliant and Halogen Free