The LM2673 series is a monolithic integrated circuit that provides 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. 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 guaranteed to a ±2% tolerance. The clock frequency is controlled to within a ±11% tolerance.
The LM2673 Simple Switcher is a monolithic step‑down (buck) switching regulator capable of delivering up to 3 A. It offers high efficiency (up to 94 %), a wide input voltage range of 8 V to 40 V, and programmable peak current limit from 2 A to 5 A. Fixed output versions are available at 3.3 V, 5 V, and 12 V, with an adjustable version covering 1.2 V to 37 V.
The handbook includes connection diagrams, ordering information for TO‑220, TO‑263, and LLP packages, absolute maximum ratings, electrical characteristics, and typical performance graphs such as efficiency versus input voltage and load transient response. Design notes cover soft‑start, thermal shutdown, and layout recommendations.
| Input voltage range | 8 V to 40 V |
|---|---|
| Fixed output voltages | 3.3 V, 5 V, 12 V |
| Efficiency | up to 94 % |
| Switching frequency | 260 kHz |
The LM2673 operates with an input voltage from 8 V up to 40 V.
Fixed output versions are offered at 3.3 V, 5 V, and 12 V.
The regulator uses a 260 kHz fixed‑frequency oscillator.
Efficiency can reach up to 94 % depending on conditions.