1 Features

• Designed for rugged industrial applications:

– Junction temperature range –40°C to +150°C

– Input transient protection up to 70 V

– Wide input voltage range: 3.0 V (falling

threshold) to 65 V

– Low EMI and minimized switch node ringing

– Adjustable, 5-V fixed output voltage options

available

• Suited for scalable industrial power supplies:

– Pin compatible with LMR36506 (65 V, 600 mA)

– Adjustable switching frequency: 200 kHz to 2.2

MHz with RT pin variant

• Minimized solution size and cost:

– Highest power density with internal

compensation and reduced external component

count

– Ultra-small, 2-mm × 2-mm HotRod™ package

with wettable flanks available

• High efficiency across load range with low power

dissipation:

– > 90 peak efficiency at 1 MHz (5 VOUT

adjustable)

• Ultra-low operating quiescent current at no load

– 4 μA at 24 VIN to 3.3 VOUT (fixed output option)

2 Applications

• Factory automation: field transmitters and process

sensors

• Building automation: HVAC and fire safety

• Appliances: garden and power tools

3 Description

The LMR36503 is the industry smallest 65 V, 0.3

A synchronous step-down DC/DC converter in 2-

mm × 2-mm HotRod package. This easy-to-use

converter can handle input voltage transients up to

70 V, provide excellent EMI performance and support

fixed 5 V and other adjustable output voltages. The

transient tolerance reduces the necessary design

effort to protect against input overvoltage and meets

the surge immunity requirements of IEC 61000-4-5.

The LMR36503 uses the peak current mode control

architecture with internal compensation to maintain

stable operation with minimal output capacitance. The

LMR36503 with the right resistor selection from the

RT pin to ground can be externally programmed

to any desired switching frequency of operation

over a wide range from 200 kHz to 2.2 MHz. The

precision EN/UVLO feature allows precise control of

the device during the start-up and shutdown. The

power-good flag, with built-in glitch filter and delayed

release, offers a true indication of the system status,

eliminating the requirement for an external supervisor.

The compact solution size and rich feature set of

LMR36503 simplifies implementation for a wide range

of industrial applications.