RT6253A/B
17V Input, 3A, ACOT
TM
Buck Converter with Both FETs OC
Protection
General Description
The RT6253A/B is a simple, easy-to-use, 3A
synchronous step-down DC-DC converter with an input
supply voltage range of 4.5V to 17V. The device
possesses an accurate reference voltage and
integrates low R
DS(ON)
power MOSFETs to achieve
high efficiency.
The RT6253A/B adopts Advanced Constant On-Time
(ACOT
TM
) 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 RT6253A
operates in automatic PSM that maintains high
efficiency during light load operation. The RT6253B
operates in Forced PWM that helps meet tight voltage
regulation accuracy requirements.
The RT6253A/B senses both FETs current for a robust
over-current protection (OCP). 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 (OTP) to provide safe and
smooth operation in all operating conditions.
Features
Integrated 95m and 50m FETs
Continuous Current
TSOT-23-6
(FC) : 3A
SOT-563 (FC) : 2.5A
Input Supply Voltage Range : 4.5V to 17V
Maximum Output Voltage Range : 7V
TM
Advanced Constant On-Time (ACOT
) Control
Ultrafast Transient Response
Optimized
for Low-ESR Ceramic Output
Capacitors
High Accuracy Feedback Reference Voltage :
1%
Optional for Operation Modes :
RT6253A : Power Saving Mode (PSM)
RT6253B : Forced PWM Mode
Fixed Switching Frequency : 580kHz
Enable Control and Fixed Soft-Start with typ.
1ms
Safe Start-Up from Pre-biased Output
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
Simplified Application Circuit
RT6253A/B
V
IN
C
IN
SW
Enable
EN
GND
FB
R
FB2
R
FB1
C
FF
VIN
BOOT
C
BOOT
L
V
OUT
C
OUT
R
BOOT
(Optional)
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS6253A/B-01
September
2019
www.richtek.com
1
RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
