The RTQ2949 is a 3A, high-efficiency, peak current mode control asynchronous step-down converter. The device operates with input voltages from 4V to 42V which is optimized for automotive applications. The device can program the output voltage between 0.8V to VIN and is protected from load dump transients up to 65V which eases input surge protection design. The low quiescent current design with the integrated low RDS(ON) of high-side MOSFET achieves high efficiency over the wide load range. The peak current mode control with simple external compensation allows the use of small inductors and results in fast transient response and good loop stability.

The wide switching frequency of 100kHz to 2500kHz allows for efficiency and size optimization when selecting the output filter components. The ultra-low minimum on-time enables constant-frequency operation even at very high step-down ratios. For switching noise sensitive applications, it can be externally synchronized from 300kHz to 2200kHz. The build-in spread-spectrum frequency modulation further helping system designers with better EMC management.

The RTQ2949 provides complete protection functions such as input under-voltage lockout, output under-voltage protection, output over-voltage protection, over-current protection, and thermal shutdown. Cycle-by-cycle current limit provides protection against shorted outputs, and soft-start eliminates input current surge during start-up. The RTQ2949 is available in SOP-8 (Exposed pad) package.


  • Automotive, Communications and Industrial 12V, 24V Power Systems
  • Industrial Automation and Motor Control
  • Vehicle Accessories : GPS, Entertainment
  • USB Charging Ports and Battery Chargers
Key Spec.
Status Active
Vin (min) (V) 4
Vin (max) (V) 42
Number of Outputs 1
Vout (min) (V) 0.8
Vout (max) (V) 42
Output Adj. Method Resistor
Iout (max) (A) 3
Current Limit (typ) (A) 4.5
Freq (min) (kHz) 100
Freq (max) (kHz) 2500
Ext Sync Yes
Ron_HS (typ) (mOhm) 150
Iq (typ) (mA) 0.09
Features 100% Duty Cycle;AEC-Q100;Adjustable Frequency;Built-in Bootstrap Switch;Current Mode Control;Cycle-by-Cycle Current Limit;Enable Input;External Synchronization;OCP;OTP;OVP;PSM;UVP
Package Type PSOP-8
  • AEC-Q100 Grade 1 Qualified
  • FMEA Compliant Pinout
  • Wide Input Voltage Range
    ► 4.5V to 42V
    ► 4V to 42V (Soft-start is finished)
  • Wide Output Voltage Range : 0.8V to VIN
  • 0.8V ±1.5% Reference Accuracy
  • Peak Current Mode Control
  • Integrated 150mΩ High-Side MOSFET
  • Low Quiescent Current : 90μA
  • Low Shutdown Current : 1.3μA
  • Adjustable Switching : 100kHz to 2.5MHz
  • Synchronizable Switching : 300kHz to 2.2MHz
  • Power Saving Mode (PSM) at Light Load
  • Built-In Spread-Spectrum Frequency Modulation
  • Low Dropout at Light Loads with Integrated Boot Recharge FET
  • Enable Control
  • Adjustable UVLO Voltage and Hysteresis
  • Adjacent Pin-Short Protection
  • Built-In UVLO, UVP, OVP, OCP, OTP
TitleLast UpdateDownload
42VIN, 3A, Asynchronous Step-Down Converter with Low Quiescent Current2020/07/31
Reference Design
TitleLast UpdateDownload
Richtek Load Transient Tool2022/07/25
Part NumberPackage TypePackage Qty.Free SampleBuy From Authorized Distributor
RTQ2949GSP-QAPSOP-82500 Request Buy from Distributor