Automotive 65V, 8A synchronous buck converter optimized for low-EMI | RZY | 26 | -40 to 150

The LM656x0-Q1 is a synchronous buck DC/DC converter offered from a family of

devices with mitigated interference and noise technology using architecture 1

features (MINT 1) that enable low EMI, high power density, and excellent conversion

efficiency. Integrated power MOSFETs with low RDS(on) enable up to 8A of

output current across a wide VIN range of 3.5V to 65V (with transients to 70V).

Phase stackable with synchronized

interleaving, the peak current-mode control architecture of the LM656x0-Q1 supports accurate current sharing with

paralleled phases for higher output currents. AUTO mode enables frequency foldback

during light-load operation, giving high light-load efficiency and a no-load input

current as low as 2.2µA, which extends operating run-time in battery-powered

systems.

A high-side switch minimum on-time of

36ns facilitates large step-down ratios, enabling the direct conversion from 24V or

48V automotive inputs to low-voltage rails

for reduced system cost and complexity. The package has several NC pins between

critical power pins, which improve the Failure Modes and Effects Analysis (FMEA)

result.

The LM656x0-Q1 includes several features to simplify

compliance with CISPR 25 and automotive emissions requirements.

First, a symmetrical pinout provides excellent input capacitor placement and enables

an ultra-low effective value for the power-loop parasitic inductance, which reduces

switching losses and improves EMI performance at high input voltage and high

switching frequency. A pin-selectable switch-node slew-rate control feature further

reduces emissions at high frequencies. To lower input capacitor

ripple current and EMI filter size, interleaved operation using a SYNCOUT signal

with 180° phase shift works well for cascaded, multichannel or multiphase

designs. Resistor-adjustable switching frequency as high as 2.2MHz can be

synchronized to an external clock source to eliminate beat frequencies in

noise-sensitive applications. Finally, the LM656x0-Q1

has dual-random spread spectrum (DRSS), a unique EMI-reduction feature that combines

low-frequency triangular and high-frequency random modulations to mitigate

disturbances across lower and higher frequency bands, respectively.

Additional

features of the LM656x0-Q1 include 150°C maximum

junction temperature operation, open-drain power-good (PG) indicator for fault

reporting and output voltage monitoring, precision enable input for input UVLO

protection, monotonic start-up into prebiased loads, dual-input VCC bias

subregulator powered from VIN or BIAS, hiccup-mode overload protection, and thermal

shutdown protection with automatic recovery.

The LM656x0-Q1

is qualified to AEC-Q100 grade 1 for automotive

applications and comes in a 4.5mm × 4.5mm, thermally enhanced, 26-pin eQFN

package with additional pin clearance for increased reliability. Also included are

wettable-flank pins to facilitate optical inspection during manufacturing.

Leveraging a flip-chip routable leadframe (FCRLF) packaging technique, the LM656x0-Q1 with useable current, lifetime reliability,

and cost advantages targets applications requiring high power density. The wide

input voltage range, low quiescent current consumption, high-temperature operation,

cycle-by-cycle current limit, low EMI signature, and small design size provide an

excellent point-of-load regulator design for applications requiring enhanced

robustness and durability.