The RTQ2118A combines a charging port controller and a 3A synchronous buck converter.

The RTQ2118A provides the electrical signatures on D+/D- to support charging schemes compatible with the USB 2.0 Battery Charging Specification BC1.2 and Chinese Telecommunication Industry Standard YD/T 1591-2009. Auto-detect mode is also integrated which supports USB 2.0 Battery Charging Specifica­tion BC1.2 Dedicated Charging Port (DCP), Divider 3 mode and 1.2V shorted mode to comply with the legacy fast charging mode of mobile devices.

The RTQ2118A integrates a high efficiency, monolithic synchronous buck converter that can deliver up to 3A output current from a 3V to 36V wide range input supply and is protected from load-dump transients up to 42V.

The RTQ2118A has constant current control to achieve adjustable USB current limit and implement the current sense signal for adjustable USB power output voltage with load line compensation. The converter includes optional spread-spectrum frequency modulation to overcome EMI issue and complete protection for safe and smooth operation in all applied conditions. Protection features include cycle-by-cycle current limit for protection against shorted outputs, soft-start control to eliminate input current surge during start-up, input under-voltage lockout, output under-voltage protection, output over-voltage protection and over-temperature protection. The RTQ2118A can be used to support Type-A connector.

The RTQ2118A is fully specified over the temperature range of TJ = -40°C to 125°C and available in WETD-VQFN-32L 5x5.


  • Automotive Car Chargers
  • USB Power Chargers
Key Spec.
Status Active
Vin (min) (V) 3
Vin (max) (V) 36
Number of Outputs 1
Vout (min) (V) 0.8
Vout (max) (V) 6
Output Adj. Method Resistor
Iout (max) (A) 3
Current Limit (typ) (A) 3.3
Freq (typ) (kHz) 2200
Freq (min) (kHz) 300
Freq (max) (kHz) 2200
Ext Sync Yes
Ron_HS (typ) (mOhm) 70
Ron_LS (typ) (mOhm) 70
Iq (typ) (mA) 0.15
Features AEC-Q100;Adjustable Current Limit;Adjustable Frequency;Adjustable Soft-Start;Built-in Bootstrap Switch;COT Control;Current Mode Control;Cycle-by-Cycle Current Limit;Enable Input;External Synchronization;OCP;OTP;OVP;PSM;Power Good;SCP;Selectable (PSM or PWM);UVP
Package Type WETD-VQFN5x5-32
  • USB Charging Port Controller
    ► Automatic DCP Modes
        ♦ DCP Shorted Mode and YD/T 1591-2009
        ♦ 2.7V Divider 3 Mode
        ♦ 1.2V Mode
  • 36V 3A Synchronous Buck Converter
    ► 3V to 36V Input Voltage Range
    ► 3A Continuous Output Current
    ► CC/CV Mode Control
    ► Adjustable and Synchronizable Switching Frequency : 300kHz to 2.2MHz
    ► Selectable PSM/PWM at Light Load
    ► Adjustable Soft-Start
    ► Adjustable USB Power Output Voltage between 5V and 6V with Load Line Compensation
    ► Optional Spread-Spectrum Frequency Modulation for EMI Reduction
  • Protection Function
    ► DS+/DS- OVP
    ► Over-Temperature Protection
    ► Cycle-by-Cycle Over-Current Limit Protection
    ► Input Under-Voltage Protection
    ► VBUS Over-Voltage Protection
    ► Adjacent Pin-Short Protection
  • Power Good Indicator
  • Enable Control
  • HBM 8kV on DS+/DS- Pins
  • Wettable Flank Package
  • AEC-Q100 Grade 1 Qualified
  • Ambient Temperature Range : -40°C to 125°C
  • Junction Temperature Range : -40°C to 125°C
TitleLast UpdateDownload
Charging Port Controller and Integrated 36V 3A Synchronous Buck Converter2021/09/02
Technical Documents
TitleItem TypeLast UpdateDownload
Richtek Featured Product Tree [Aug., 2023] Selection Guide2023/08/07
Richtek Selection Guide [Oct., 2022] Selection Guide2022/10/01
Richtek Automotive Product Selection Guide [Sep., 2022] Selection Guide2022/09/01
Reference Design
TitleLast UpdateDownload
Richtek Load Transient Tool2022/07/25