Automotive, 80V synchronous buck DC/DC controller with ultra-low IQ

The LM5148-Q1 is a 80V, ultra-low IQ synchronous buck DC/DC controller for high-current, single-output applications. The controller uses a peak current-mode control architecture for easy loop compensation, fast transient response, and excellent load and line regulation. The LM5148-Q1 can be set up in dual-phase mode (paralleled output) with accurate current sharing for high-current applications. The device can operate at input voltages as low as 3.5V, at nearly 100% duty cycle if needed.

The LM5148-Q1 has a unique EMI reduction feature known as Dual Random Spread Spectrum (DRSS). Combining low-frequency triangular and high-frequency random modulations mitigates EMI disturbances across lower and higher frequency bands, respectively. This hybrid technique aligns with the multiple resolution bandwidth (RBW) settings specified in industry-standard EMC tests.

Additional features of the LM5148-Q1 include 150°C maximum junction temperature operation, user-selectable diode emulation for lower current consumption at light-load conditions, open-drain power-good flag for fault reporting and output monitoring, precision enable input, monotonic start-up into prebiased load, integrated VCC bias supply regulator, internal 3ms soft-start time, and thermal shutdown protection with automatic recovery.

The LM5148-Q1 controller comes in 3.5mm × 5.5mm, 24-pin VQFN and a 19-pin VQFN, 4.50mm × 3.5mm thermally enhanced packages with wettable flank pins to facilitate optical inspection during manufacturing. For high voltage applications that require additional pin spacing between low voltage pins and high voltage pins, the pin spacing was increased to 0.6mm by removing a pin. To increase the spacing from VIN to the exposed pad, the exposed pad was reduced to 1.7mm × 2.3mm.