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.

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