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12A, 17V, High Efficiency Synchronous Step-Down Converter

RT6243A/RT6243B

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The RT6243A/B is a high-performance, synchronous step-down converter that can deliver up to 12A output current with an input supply voltage range of 4.5V to 17V. The device integrates low RDS(ON) power MOSFETs, accurate 0.6V reference and an integrated diode for bootstrap circuit to offer a very compact solution.

The RT6243A/B adopts Advanced Constant On-Time (ACOTTM) control architecture that provides ultrafast transient response and further reduce the external-component count. In steady states, the ACOTTM operates in nearly constant switching frequency over line, load and output voltage ranges and makes the EMI filter design easier.

The device offers a variety of functions for more design flexibility. The selectable switching frequency, current limit level and PWM operation modes makes the RT6243A/B easy-to-use over wide application range. Independent enable control input pin and power good indicator are also provided for easy sequence control. To control the inrush current during the startup, the device provides a programmable soft start-up by an external capacitor connected to the SS pin. Fully protection features are also integrated in the device including the cycle-by-cycle current limit, OVP, UVP, input UVLO and OTP.

The RT6243A/B is available in a thermally enhanced VQFN-18L 3.5x3.5 (FC) package.

Applications

  • Server, Storage and Network Equipment
  • Telecom Infrastructure
  • Point of Load (POL) Power Modules
  • High Density DC-DC Converters
  • High End Digital TV
Key Spec.
RT6243A RT6243B
Status Active Active
Vin (min) (V) 4.5 4.5
Vin (max) (V) 17 17
Number of Outputs 1 1
Vout (min) (V) 0.6 0.6
Vout (max) (V) 5.5 5.5
Output Adj. Method Resistor Resistor
Iout (max) (A) 12 12
Current Limit (typ) (A) 11.5;13.8 11.5;13.8
Freq (typ) (kHz) 1200;400;800 1200;400;800
Ext Sync No No
Ron_HS (typ) (mOhm) 9.8 9.8
Ron_LS (typ) (mOhm) 4.5 4.5
Iq (typ) (mA) 0.6 0.6
Features ACOT Control;Adjustable Frequency;Adjustable Soft-Start;Built-in Bootstrap Switch;Cycle-by-Cycle Current Limit;Enable Input;Fast Transient Response;Internal Compensation;OTP;Power Good;Selectable (PSM or PWM);Stable with Ceramic Capacitor;UVP ACOT Control;Adjustable Frequency;Adjustable Soft-Start;Built-in Bootstrap Switch;Cycle-by-Cycle Current Limit;Enable Input;Fast Transient Response;Internal Compensation;OTP;Power Good;Selectable (PSM or PWM);Stable with Ceramic Capacitor;UVP
Package Type VQFN3.5x3.5-18(FC) VQFN3.5x3.5-18(FC)
Features
  • 4.5V to 17V Input Voltage Range
  • Integrated 9.8mΩ/4.5mΩ MOSFETs
  • 0.6V ±1% Voltage Reference
  • Adjustable Output Voltage from 0.6V to 5.5V
  • Supports Ceramic Output Capacitor
  • ACOTTM Control for Fast Transient Response
  • Selectable Switching Frequency (400kHz/800kHz/1200kHz)
  • Selectable Current Limit Level
  • Power Good Indicator
  • Programmable Soft-Start Time with a Default 1ms
  • Monotonic Start-Up into Pre-Biased Outputs
  • 18-Lead VQFN (FC) Package
Datasheet
TitleLast UpdateShareDownload
12A, 17V, High Efficiency Synchronous Step-Down Converter2019/01/25
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