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.