1 Features

• Functional Safety-Capable

– Documentation available to aid functional safety

system design

• Wide operating input voltage: 3V to 36V (42V

absolute maximum)

• Ultra-low quiescent current

– Shutdown current: 0.65μA

– No load standby current: 5μA

• Pin programmable output voltage options available

in fixed 3.3V/ADJ and 5V/ADJ

– Adjustable output voltage range from 1V to 20V

• Low minimum tON (30ns typical)

• Optimized for low electromagnetic interference

(EMI) requirements:

– Low inductance HotRod™ QFN package

– Spread spectrum options available

• Programmable switching frequency from 200kHz –

2.2MHz

• FPWM, PFM, or external frequency

synchronization available

• Designed for scalable power supplies

– Pin compatible with LMR60406, LMR60410,

LMR60420, and LMR60430

• Power-Good output for power sequencing

2 Applications

• Factory automation and control

• Appliances

• Building automation

3 Description

The LMR60440 is a 3V to 36V (42V transient), 4A

synchronous buck converter designed for industrial

applications. The LMR60440 offers variants with

spread spectrum in an ultra-compact, 2.5mm × 2mm,

HotRod QFN-9 package, which reduces inductance

and achieves low electromagnetic interference (EMI)

performance to facilitate qualification of industrial and

other noise-sensitive designs. All device variants are

capable of output voltages ranging from 1V to 20V

by including a resistor divider between the output

voltage node, feedback, and ground. Each variant of

the device is also capable of delivering a fixed output

voltage by connecting the output voltage node directly

to the feedback pin. The Device Comparison Table

provides details on the fixed output voltage options.

The current-mode control architecture with 40ns

minimum on-time allows high conversion ratios at high

frequencies, easy loop compensation, fast transient

response, and excellent load and line regulation.

An open drain power-good output facilitates power

sequencing requirements. The MODE/SYNC pin of

the LMR60440 allows the user to select between

modes of operation. Forced pulse width modulation

(FPWM) mode results in constant switching frequency

across load while auto mode allows for seamless

transitions between pulse width modulation (PWM)

and pulse frequency modulation (PFM) switching. In

auto mode, the LMR60440 consumes only 5μA of

quiescent current, which makes sure of high efficiency

at all loads. Few external components are needed

allowing for compact PCB layout. The LMR60440 is a

part of a family of pin compatible devices ranging in

current levels from 0.6A to 6A.