The RTQ2158B is a high-performance, Advanced Constant On-Time (ACOT®) monolithic synchronous step-down DC-DC converter that can deliver up to 8A output current from a 2.85V to 6.5V input supply. 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 RTQ2158B adopts Advanced Constant On-Time (ACOT®) control architecture that provides ultrafast transient response and further reduces 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 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 RTQ2158B-QA is available in a thermally enhanced WET-WQFN-21L 4x4 (FC) package.


  • Automotive Systems
  • Infotainment and Cockpit Systems
  • Vehicle ADAS ECU
  • Connected Car Systems
  • High Density DDR Memory
  • Broadband Communications and Industrial Systems
Key Spec.
Status Active
Vin (min) (V) 2.85
Vin (max) (V) 6.5
Number of Outputs 1
Vout (min) (V) 0.6
Vout (max) (V) 3.3
Output Adj. Method Resistor
Iout (max) (A) 8
Current Limit (typ) (A) 9.8
Freq (typ) (kHz) 460
Ext Sync No
Ron_HS (typ) (mOhm) 15
Ron_LS (typ) (mOhm) 10
Iq (typ) (mA) 0.5
Features ACOT Control;AEC-Q100;Adjustable Soft-Start;Built-in Bootstrap Switch;Cycle-by-Cycle Current Limit;Enable Input;Fast Transient Response;Force PWM;Internal Compensation;OTP;Power Good;Stable with Ceramic Capacitor;Stable with Ceramic Capacitor;UVP
Package Type WET-WQFN4x4-21(FC)
  • AEC-Q100 Grade 1 Qualified
  • Dramatically Fast Transient Response
  • Steady 460kHz Switching Frequency
  • Extremely High Efficiency 15mΩ/10mΩ MOSFETs
  • Advanced COT Control Loop
  • Wide Input Voltage Range from 2.85V to 6.5V
  • Optimized for Ceramic Output Capacitors
  • Internal Start-Up into Pre-biased Outputs
  • Power Good Indicator
  • Enable Control
  • Over-Current and Over-Temperature Protections
  • Under-Voltage Protection with Hiccup Mode
TitleLast UpdateDownload
8A, 6.5V, 460kHz Synchronous Step-Down Converter2024/01/25
Technical Documents
TitleItem TypeLast UpdateDownload
Richtek Product Selection Guide [Jan., 2024] Selection Guide2024/01/18
Richtek Featured Product Tree [Aug., 2023] Selection Guide2023/08/07
Reference Design
TitleLast UpdateDownload
Richtek Load Transient Tool2022/07/25