1 Features
• Wide input voltage range: 3V to 65V (70V transient
< 100ms)
– Meets LV148 / ISO21780 requirements
• Designed for low EMI requirements
– Facilitates CISPR 11 class B compliance
– Mode pin configurable ±5% or ±10% dualrandom
spread spectrum reducing peak
emissions
– Enhanced HotRod™ QFN package with
symmetrical pinout
– 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 conversion 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
– 3.6mm × 2.6mm, wettable flank, 20-pin
package
– Pin compatible with 36V 4/6/8A LM654x0-Q1
– ϴJA = 24.0°C/W (LM65645EVM)
• Create a custom design using the LM656x5 with
the WEBENCH® Power Designer

2 Applications
• Industrial transport systems
• Factory automation and control systems
• Medical imaging systems

3 Description
The LM656x5 are a family of 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
LM656x5 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. A pin-selectable ±5% or ±10% dual-random
spread spectrum (DRSS) significantly reduces peak
emissions through a combination of triangular and
pseudo-random modulation while keeping output
voltage ripple very low. 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.