SNVSB29C October 2018 – June 2021 LM5143-Q1
The LM5143-Q1 is a dual-phase or dual-channel switching controller that features all of the functions necessary to implement a high-efficiency synchronous buck power supply operating over a wide input voltage range from 3.5 V to 65 V. The LM5143-Q1 is configured to provide a fixed 3.3-V or 5-V output, or an adjustable output between 0.6 V to 55 V. This easy-to-use controller integrates high-side and low-side MOSFET drivers capable of sourcing 3.25-A and sinking 4.25-A peak current. Adaptive dead-time control is designed to minimize body diode conduction during switching transitions.
Current-mode control using a shunt resistor or inductor DCR current sensing provides inherent line feedforward, cycle-by-cycle peak current limiting, and easy loop compensation. It also supports a wide duty cycle range for high input voltage and low dropout applications as well as when a high voltage conversion ratio (for example, 10-to-1) is required. The oscillator frequency is user-programmable between 100 kHz to 2.2 MHz, and the frequency can be synchronized as high as 2.5 MHz by applying an external clock to DEMB.
An external bias supply can be connected to VCCX to maximize efficiency in high input voltage applications. A user-selectable diode emulation feature enables discontinuous conduction mode (DCM) operation to further improve efficiency and reduce power dissipation during light-load conditions. Fault protection features include the following:
The LM5143-Q1 incorporates features to simplify the compliance with CISPR 25 automotive EMI requirements. An optional spread spectrum frequency modulation (SSFM) technique reduces the peak EMI signature, while the adaptive gate drivers with slew rate control minimize high-frequency emissions. Finally, 180° out-of-phase interleaved operation of the two controller channels reduces input filtering and capacitor requirements.
The LM5143-Q1 is provided in a 40-pin VQFNP package with wettable flanks and an exposed pad to aid in thermal dissipation.