The LM5143A-Q1 is a 65-V DC/DC synchronous buck controller for high-current single or dual outputs. Deriving from a family of wide-VIN range controllers, the device uses an interleaved, stackable, peak current-mode control architecture for easy loop compensation, fast transient response, excellent load and line regulation, and accurate current sharing with paralleled phases for higher output current. A high-side switch minimum on time of 65 ns provides large step-down ratios, enabling the direct conversion from 12-V, 24-V, or 48-V inputs to low-voltage rails for reduced system complexity and cost. The LM5143A-Q1 continues to operate during input voltage dips as low as 3.5 V, at nearly 100% duty cycle if needed.
The 15-μA no-load quiescent current with the output voltage in regulation extends operating run-time in battery-powered automotive systems. Power the LM5143A-Q1 from the output of the switching regulator or another available source for even lower input quiescent current and power loss.
| Part Number | Package(1) | Body Size (NOM) |
|---|---|---|
| LM5143A-Q1 | VQFN (40) | 6.00 mm × 6.00 mm |
| DATE | REVISION | NOTES |
|---|---|---|
| May 2022 | * | Initial release |
Several features are included to simplify compliance with EMI requirements. Adaptively timed, high-current MOSFET gate drivers with adjustable slew rate control minimize body diode conduction during switching transitions, reducing switching losses and improving thermal and EMI performance at high input voltage and high switching frequency. To reduce input capacitor ripple current and EMI filter size, 180° interleaved operation is provided for two outputs. A 90° out-of-phase clock output works well for cascaded, multichannel, or multiphase power stages. Resistor-adjustable switching frequency as high as 2.2 MHz can be synchronized to an external clock source up to 2.5 MHz to eliminate beat frequencies in noise-sensitive applications. Optional triangular spread spectrum modulation further improves the EMI signature.
Additional features of the LM5143A-Q1 include 150°C maximum junction temperature operation, user-selectable diode emulation for lower current consumption at light-load conditions, configurable soft-start functions, open-drain power-good flags for fault reporting and output monitoring, independent enable inputs, monotonic start-up into prebiased loads, an integrated VCC bias supply regulator with automatic changeover to an external bias connected at VCCX, programmable hiccup-mode overload protection, and thermal shutdown protection with automatic recovery. Current is sensed using the inductor DCR for highest efficiency or an optional shunt resistor for high accuracy.
The LM5143A-Q1 controller comes in a 6-mm × 6-mm thermally enhanced, 40-pin VQFN package. The wide input voltage range, low quiescent current consumption, high-temperature operation, cycle-by-cycle current limit, low EMI signature, and small solution size provide an ideal point-of-load regulator solution for applications requiring enhanced reliability and durability.