LMS3655-Q1, LMS3635-Q1
SNAS714C – NOVEMBER 2016 – REVISED AUGUST 2021
LMS3635-Q1 3.5-A, LMS3655-Q1 5.5-A, 36-V Synchronous, 400-kHz Step-Down
Converter
1 Features
3 Description
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AEC-Q100-qualified for automotive applications
– Device temperature grade 1: –40°C to +125°C
ambient operating temperature
– Device HBM classification level 2
– Device CDM classification level C6
96% Peak efficiency while converting 12 V to 5 V
Low EMI and minimized switch node ringing
400-kHz (±10%) fixed switching frequency
–40°C to +150°C junction temperature range
External frequency synchronization
RESET output with internal filter and 3-ms release
timer
Automatic light load mode for improved efficiency
Pin-selectable forced PWM mode
Built-In compensation, soft start, current limit,
thermal shutdown, and UVLO
0.35-V dropout with 3.5-A Load at 25°C (Typical)
18-µA IQ_VIN: quiescent current at 3.3 VOUT and no
load (typical)
The LMS3635-Q1 and LMS3655-Q1 synchronous
buck regulators are optimized for high performance
applications, providing an output voltage of 3.3 V, 5
V, or an adjustable output of 1 V to 20 V. Seamless
transition between PWM and PFM modes, along with
a low quiescent current, ensures high efficiency and
superior transient responses at all loads.
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Advanced high-speed circuitry allows the LMS3655-
Q1 to regulate an input of 24 V to an output of 3.3 V
at a fixed frequency of 400 kHz while also enabling
a continuous load current of 5.5 A. An innovative
frequency foldback architecture allows this device to
regulate a 3.3-V output from an input voltage of only
3.5 V. The input voltage can range up to 36 V, with
transient tolerance up to 42 V, easing input surge
protection design.
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An open-drain reset output, with built-in filtering and
delay, provides a true indication of system status.
This feature negates the requirement for an additional
supervisory component, saving cost and board space.
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Output voltage: 5 V, 3.3 V, and ADJ (1 V to 20 V)
±1.5% reference voltage tolerance
Create a custom design using the LMS3655-Q1
with the WEBENCH® Power Designer
Device Information
DEVICE NAME
LMS3635-Q1
PACKAGE(1)
BODY SIZE
2 Applications
SON (22)
4.00 mm × 5.00 mm
LMS3655-Q1
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Automotive USB charge
Driver monitoring
Surround view system ECU
Mechanically scanning LIDAR
Vehicle to vehicle
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
100%
98%
96%
94%
92%
90%
88%
86%
84%
82%
80%
VIN = 12
VIN = 24
0.001
0.01
0.1
Output Current (A)
1
10
LMS3
LMS3655-Q1 Conducted EMI: VOUT = 5 V, IOUT = 5 A
LMS3655-Q1 Efficiency: VOUT = 5 V
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.