9A, 6.5V, 1MHz, ACOT® Synchronous Step-Down Converter with I2C Interface


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The RT5759 is a high-performance, synchronous step-down DC-DC converter that can deliver up to 9A output current from a 3V to 6.5V input supply. The output voltage can be programmable from 0.6V to 1.5V with I2C controlled 7-Bits VID.

The device integrates low RDS(ON) power MOSFETs, accurate 0.6V reference and an integrated diode of bootstrap circuit to offer a very compact solution.

The RT5759 adopts Advanced Constant On-Time (ACOT®) control architecture that provides ultrafast transient response and further reduce the external-component count. In steady states, the ACOT® operates in nearly constant switching frequency over line, load and output voltage ranges and makes the EMI filter design easier. The RT5759 offers automatic PSM that maintains high efficiency during light load operation. The RT5759 can also operate in Forced-CCM through I2C setting that helps meet tight voltage regulation accuracy requirements.

The device offers a variety of functions for more design flexibility. The switching frequency, current limit level and over temperature threshold are selectable via I2C. Independent enable control input pin and power good indicator are also provided for easy sequence control. Besides, the designers can also command the device to be enabled or shutdown via the I2C interface.

The device offers Independent enable control input pin and power good indicator for easily 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 control, UVP, input UVLO and OTP.

The RT5759 is available in a thermally enhanced UQFN-13L 3x3 (FC) package.


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Key Spec.
Status Active
Vin (min) (V) 3
Vin (max) (V) 6.5
Number of Outputs 1
Vout (min) (V) 0.6
Vout (max) (V) 1.5
Output Adj. Method Digital
Iout (max) (A) 9
Current Limit (typ) (A) 10.8
Freq (min) (kHz) 600
Freq (max) (kHz) 1500
Ext Sync No
Ron_HS (typ) (mOhm) 12
Ron_LS (typ) (mOhm) 8
Iq (typ) (mA) 0.1
Interface I2C
Features ACOT Control;Adjustable Current Limit;Adjustable Frequency;Adjustable Soft-Start;Built-in Bootstrap Switch;Cycle-by-Cycle Current Limit;Enable Input;Fast Transient Response;Selectable (PSM or PWM);Stable with Ceramic Capacitor;UVP
Package Type UQFN3x3-13(FC)
  • Dramatically Fast Transient Response
  • Steady 1MHz ±20% Switching Frequency
  • Advanced COT Control Loop
  • Optimized for Ceramic Output Capacitors
  • 3V to 6.5V Input Voltage Range
  • Integrated 12mΩ/8mΩ MOSFETs
  • Internal Start-Up into Pre-Biased Outputs
  • Power Good Indicator
  • Enable Control
  • Over-Current and Over-Temperature Protections
  • Under-Voltage Protection with Hiccup Mode
  • VID Control Range Via I2C Compatible Interface : 0.6V to 1.5V step = 10mV
TitleLast UpdateShareDownload
9A, 6.5V, 1MHz, ACOT® Synchronous Step-Down Converter with I2C Interface2018/05/22
Technical Documents
TitleLast UpdateShareDownload
Richtek Selection Guide [Oct., 2020]2020/12/30