3A Step-Down Voltage Regulator with Adjustable Current Limit - LM2673


3A Step-Down Voltage Regulator with Adjustable Current Limit

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The LM2673 series of regulators are monolithic integrated circuits which provide all of the active functions for a step-down (buck) switching regulator capable of driving up to 3A loads with excellent line and load regulation characteristics. High efficiency (>90%) is obtained through the use of a low ON-resistance DMOS power switch. The series consists of fixed output voltages of 3.3V, 5V and 12V and an adjustable output version.

The SIMPLE SWITCHER concept provides for a complete design using a minimum number of external components. A high fixed frequency oscillator (260KHz) allows the use of physically smaller sized components. A family of standard inductors for use with the LM2673 are available from several manufacturers to greatly simplify the design process.

Other features include the ability to reduce the input surge current at power-ON by adding a softstart timing capacitor to gradually turn on the regulator. The LM2673 series also has built in thermal shutdown and resistor programmable current limit of the power MOSFET switch to protect the device and load circuitry under fault conditions. The output voltage is ensured to a ±2% tolerance. The clock frequency is controlled to within a ±11% tolerance.


  • Efficiency Up to 94%
  • Simple and Easy to Design with (Using Off-The-Shelf External Components)
  • Resistor Programmable Peak Current Limit Over a Range of 2A to 5A
  • 150 mΩ DMOS Output Switch
  • 3.3V, 5V and 12V Fixed Output and Adjustable (1.2V to 37V) Versions
  • ±2% Maximum Output Tolerance Over Full Line and Load Conditions
  • Wide Input Voltage Range: 8V to 40V
  • 260 KHz Fixed Frequency Internal Oscillator
  • Softstart Capability
  • −40 to +125°C Operating Junction Temperature Range

SIMPLE SWITCHER is a trademark of Texas Instruments. All trademarks are the property of their respective owners. SIMPLE SWITCHER is a trademark of Texas Instruments. Switchers Made Simple is a trademark of Texas Instruments.

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Parametrics Evaluate all products in Step-Down (Buck) Converter

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Regulated Outputs (#) 1
Vin (Min) (V) 8
Vin (Max) (V) 40
Vout (Min) (V) 1.23
Vout (Max) (V) 37
Iout (Max) (A) 3
Iout2 (Max) (A) -
Vout2 (Min) (V) -
Vout2 (Max) (V) -
Topology Buck
  • Boost
  • Buck
  • Buck-Boost
  • Inverting Buck-Boost
Switching Frequency (Max) (kHz) 260
Switch Current Limit (Typ) (A) 4.5
Iq (Typ) (mA) 4.2
Duty Cycle (Max) (%) 91
Soft Start Adjustable
  • Adjustable
  • Fixed
  • None
Compensation Internal
  • External
  • Internal
  • Not Needed
Special Features Enable
  • Adjustable Current Limit
  • Adjustable UVLO
  • Dynamic Voltage Scaling
  • Enable
  • Frequency Synchronization
  • Light Load Efficiency
  • Phase Interleaving
  • Power Good
  • Synchronous Rectification
  • Tracking
Control Mode Voltage Mode
  • COT with emulated ripple
  • Constant on-time (COT)
  • Current Mode
  • D-CAP
  • D-CAP+
  • D-CAP2
  • D-CAP3
  • Voltage Mode
Preset Vout (V) -
Vref Accuracy (Typ) (%) 2
Rating Catalog
  • Automotive
  • Catalog
  • HiRel Enhanced Product
  • High Temp
  • Military
  • Space
Operating Temperature Range (C) -40 to 125 °C to °C
Approx. Price (US$) 1.85 | 1ku
Package Group DDPAK/TO-263
  • CFP
  • DDPAK/TO-263
  • MSOP-PowerPAD
  • PDIP
  • QFN
  • SO PowerPAD
  • SOIC
  • SON
  • SOT
  • SOT-23
  • TO-220
  • TO-263
  • USON
  • VQFN
  • VSON
  • WQFN
  • WSON
  Sample & Buy Reset Update

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    Min   Max   Range  
  Vin V    8.00 – 40.00V  
  Vout V    1.21 – 40.00V  
  Iout A    ≤ 3A  
  Ambient Temp °C    -40 – 125°C  
Footprint BOM Cost Efficiency
'IC Cinx Cb Rilim Css Rfb1 Rfb2 D1 L1 Cout Cin '
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