1 Features
• AEC-Q100 qualified for automotive applications:
– Temperature grade 1: –40°C to +125°C, TA
• Functional Safety-Compliant
– Developed for functional safety applications
– Documentation to aid with ISO26262 compliant
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 70V
• Designed for low EMI requirements
– Facilitates CISPR 25 class 5 compliance
– ±5% dual-random spread spectrum
– Enhanced HotRod™ QFN package with
symmetrical pinout
– Switching frequency from 300kHz to 2.2MHz
– Pin-configurable 400kHz and 2.2MHz
– Pin-configurable AUTO or FPWM operation
• Low minimum on time: 40ns (maximum)
– Enables 36V to 3.3V conversion at 2.2MHz
• High-efficiency power conversion at all loads
– > 94% peak efficiency at 24VIN, 5VOUT, 400kHz
– 2.5μA PFM no-load input current
• High power density
– Internal compensation, current limit, and TSD
– 3.6mm × 2.6mm, wettable flank, 20-pin
package
– Pin compatible with LM656x5-Q1
– ϴJA = 25.5°C/W (LM65645-Q1EVM)
• Create a custom design using the 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 70V (75V tolerant) 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.
The LM686x5-Q1 buck converters are specifically
intended for functional safety relevant applications.
An array of safety features including ABIST at startup,
redundant and fast VOUT monitoring, feedback
path failure detection, redundant temperature sensor,
thermal shutdown, and current limiting significantly
reduce the residual failure-in-time (FIT).