1 Features
• AEC-Q100 qualified for automotive applications:
– Temperature grade 1: –40°C to +125°C, TA
• Functional Safety-Compliant
– Documentation available to aid ISO 26262
system designs planned
– Systematic capability up to ASIL D
– Hardware capability up to ASIL C
– Analog built-in-self-test at start-up
– Redundant and fast (0.35μs) VOUT monitor
– Feedback path failure detection
– Redundant temperature sensor
– Excellent pin FMEA and pin spacing
• Wide input voltage range: 3V to 65V
– Meets LV148 / ISO21780 requirements
• ZEN 1 switcher technology
– Facilitates CISPR 25 class 5 compliance
– ±5% dual-random spread spectrum
– Enhanced HotRod™ QFN package
– Switching frequency from 300kHz to 2.2MHz
– Pin-configurable AUTO or FPWM operation
– Internal compensation, current limit, and TSD
• Low minimum on time: 40ns (maximum)
– Enables 36VIN to 3.3VOUT at 2.2MHz
• High-efficiency power conversion at all loads
– > 94% peak efficiency at 24VIN, 5VOUT, 400kHz
– 2.5μA switching input current at no load
• High power density
– Compact 3.6mm × 2.6mm, 20-pin eQFN
package with wettable flank
– Pin compatible with 36V 4/6/8A LM654x0-Q1
– ϴJA = 24.0°C/W (LM65645-Q1EVM)
• Create a custom design using the LM686x5-Q1
with the WEBENCH® Power Designer

2 Applications
• Advanced driver assistance systems (ADAS)
• Automotive infotainment and cluster
• Hybrid, electric, and powertrain systems

3 Description
The LM686x5-Q1 are a family of automotive buck
converters designed for high efficiency, high-power
density, and ultra-low electromagnetic interference
(EMI). The converters operate over a wide input
voltage range of 3V to 65V (70V transient < 100ms),
reducing the need for external input surge protection.
The LM686x5-Q1 comes with pin selectable fixed
output voltages of 3.3V and 5V or in adjustable
configuration. The low EMI operation is enabled
with minimized loop inductance and optimized switch
node slew rate. The current-mode control architecture
with a 30ns typical minimum on-time allows high
conversion ratios at high frequencies coupled with a
fast transient response and excellent load and line
regulation. AUTO mode enables frequency foldback
during light load operation, allowing an unloaded
current consumption as low as 1.36μA (typical) and
high light load efficiency, which extends operating runtime
in battery-powered systems.