Richtek RT6253B

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 RDS(ON) power MOSFETs to achieve high efficiency. The RT6253A/B adopts Advanced Constant On-Time (ACOTTM) 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.RT6253A is Automatic PSM and RT6253B is Forced PWM.

Features

• 3A Converter Integrated 95mΩ and 50mΩ FETs
• Input Supply Voltage Range : 4.5V to 17V
• Maximum Output Voltage Range : 7V
• Advanced Constant On-Time (ACOTTM) Control
• Ultrafast Transient Response
• Optimized for Low-ESR Ceramic Output Capacitors
• High Accuracy Feedback Reference Voltage : Typ. ±1%
• Optional for Operation Modes :
• Automatically Power Saving Mode (PSM) (RT6253A)
• Forced PWM Mode (RT6253B)
• Fixed Switching Frequency : 580kHz
• Enable Control and Internally Fixed Soft-Start
• Safe Start-Up from Pre-biased Output
• Input Under-Voltage Lockout (UVLO)
• Output Under-Voltage Protection (UVP) with Hiccup Mode
• High- / Low-side MOSFET OCP and OTP Function
• RoHS Compliant and Halogen Free

Typical applications

• Set-Top Boxes / LCD TVs / Home Networking Devices / Surveillance

More information

• Datasheet
• IC product information