1 Features

• AEC-Q100 qualified for automotive applications:

– Device temperature grade 1: –40°C to +125°C

ambient operating temperature

• Functional Safety-Capable

– Documentation available to aid functional safety

system design

• Two integrated EMI mitigation mechanisms

– Active EMI Filter for enhanced EMI

performance at lower frequencies

– Selectable dual random spread spectrum

(DRSS) for enhanced EMI performance across

low and high-frequency bands

– EMI reduced by an average of 25 dBμV

– Reduces the external differential-mode input

filter size by 50 and lowers systems cost

• Versatile synchronous buck DC/DC controller

– Wide input voltage range of 3.5 V to 80 V

– 1 accurate, fixed 3.3-V, 5-V, 12-V, or

adjustable output from 0.8 V to 55 V

– 150°C maximum junction temperature

– Shutdown mode current: 2.3 μA

– No-load sleep current: 9.5 μA

– Stackable up to two phases

• Switching frequency from 100 kHz to 2.2 MHz

– SYNC in and SYNC out capability

• Inherent protection features for robust design

– Internal hiccup-mode overcurrent protection

– ENABLE and PGOOD functions

– VCC, VDDA, and gate-drive UVLO protection

– Thermal shutdown protection with hysteresis

• Create a custom design using the LM5149-Q1 with

WEBENCH® Power Designer

2 Applications

• Automotive electronic systems

• Infotainment systems, instrument clusters, ADAS

• Body electronics

• High-voltage battery-operated systems

3 Description

The LM5149-Q1 is a 80-V, 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 LM5149-Q1 can be set up in dualphase

mode with accurate current sharing for highcurrent

applications. It can operate with VIN as low as

3.5 V, at nearly 100 duty cycle if needed.

The LM5149-Q1 has two unique EMI reduction

features: active EMI filter and dual random spread

spectrum (DRSS). The active EMI filter senses

any noise or ripple voltage on the DC input

bus and injects an out-of-phase cancellation signal

to reduce the disturbance. DRSS combines lowfrequency

triangular and high-frequency randomized

modulations to mitigate EMI across lower and higher

frequency bands, respectively. This hybrid technique

aligns with the multiple resolution bandwidth (RBW)

settings specified in industry-standard EMC tests.