3A, 36V, Synchronous Step-Down Converter


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The RT2875A/B is a high efficiency, current-mode synchronous DC-DC step-down converter that can deliver up to 3A output current over a wide input voltage range from 4.5V to 36V. The device integrates 95mΩ high-side and 70mΩ low-side MOSFETs to achieve high conversion efficiency. The current-mode control architecture supports fast transient response and simple external compensation. A cycle-by-cycle current limit function provides protection against shorted output and an external soft-start eliminates input current surge during start-up. The RT2875A/B provides complete protection functions such as input under-voltage lockout, output under-voltage protection, over-current protection and thermal shutdown.

The RT2875A/B is available in the thermal enhanced TSSOP-14 (Exposed Pad) package.


  • Point of Load Regulator in Distributed Power Systems
  • Digital Set Top Boxes
  • Broadband Communications
  • Vehicle Electronics
Key Spec.
RT2875AQ RT2875BQ
Status Active Active
Vin (min) (V) 4.5 4.5
Vin (max) (V) 36 36
Number of Outputs 1 1
Vout (min) (V) 0.6 0.6
Vout (max) (V) 24 24
Preset Vout (V)
Output Adj. Method Resistor Resistor
Iout (max) (A) 3 3
Current Limit (typ) (A) 5.5 5.5
Freq (typ) (kHz)
Freq (min) (kHz) 300 300
Freq (max) (kHz) 2100 2100
Ext Sync Yes Yes
Ron_HS (typ) (mOhm) 95 95
Ron_LS (typ) (mOhm) 70 70
Iq (typ) (mA)
Features AEC-Q100 Qualified;Adjustable Current Limit;Adjustable Frequency;Adjustable Soft-Start;Force PWM;OCP;Power Good;UVP AEC-Q100 Qualified;Adjustable Current Limit;Adjustable Frequency;Adjustable Soft-Start;Force PWM;OCP;Power Good;UVP
Package Type TSSOP-14(PP) TSSOP-14(PP)
  • 3A Output Current
  • Internal N-MOSFETs
  • Current Mode Control
  • Adjustable Switching Frequency : 300kHz to 2.1MHz
  • Adjustable Current Limit : 1.5A to 6A
  • Synchronous to External Clock : 300kHz to 2.1MHz
  • Adjustable Output Voltage from 0.6V to 24V
  • High Efficiency Up to 95%
  • Stable with Low ESR Ceramic Output Capacitors
  • Cycle-by-Cycle Current Limit
  • Input Under-Voltage Lockout
  • Output Under-Voltage Protection
  • Thermal Shutdown
  • AEC-Q100 Grade 2 Certification
  • RoHS Compliant and Halogen Free
TitleLast UpdateShareDownload
3A, 36V, Synchronous Step-Down Converter2014/06/27
Technical Documents
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Automotive Product Selection Guide2018/11/15
Richtek Wide Input Voltage Range DC/DC Power Solutions for Industrial, Automotive and LED lighting applications2018/11/01
RT2875 3A Automotive Buck Converter2017/10/18
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How to estimate control loop bandwidth from the transient response time?2017/03/30 349
Evaluation Boards
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RT2875B Synchronous Step-Down Converter Evaluation Board2017/09/04
Reference Design
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Richtek Load Transient Tool2018/11/01
Design Tool
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Richtek Designer™ Web Simulation Tool : RT2875AQGCP2018/12/10
Richtek Designer™ Web Simulation Tool : RT2875BQGCP2018/12/10
Pspice: RT2875A2018/12/10
Pspice: RT2875B2018/12/10
Part NumberPackage TypePackage Qty.Free SampleBuy From Authorized Distributor
RT2875AQGCPTSSOP-14(PP)2500 Request Buy from Distributor
RT2875BQGCPTSSOP-14(PP)2500 Request Buy from Distributor