LMS3655-Q1 Datasheet, PDF (1/10 Pages) Texas Instruments – 3.5-A /5.5-A, 36-V Synchronous, 400-kHz, Step-Down Converter

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LMS3655-Q1, LMS3635-Q1
SNAS701 – SEPTEMBER 2016
LMS3635/55-Q1, 3.5-A /5.5-A, 36-V Synchronous, 400-kHz, Step-Down Converter
1 Features
•1 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 Switch Noise
– Minimized Switch Node Ringing
– Pseudo-Random Spread Spectrum
• 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)
• 15-µA I_q – Quiescent Current at No Load (Typical)
• 3.5-A or 5.5-A Continuous Load Current
• Output Voltage Options: 5 V, 3.3 V, and ADJ (1 V
to 15 V)
• ±2% Output Voltage Tolerance
• 4-mm × 5-mm, 0.5-mm Pitch SON Package
2 Applications
• Automotive Systems
• Industrial Performance
• In-Dash Instrumentation
• Battery-Powered Applications
3 Description
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 15 V. Seamless
transition between PWM and PFM modes, along with
a low quiescent current, ensures high efficiency and
superior transient responses at all loads.
Advanced high-speed circuitry allows the LMS3635-
Q1 and LMS3655-Q1 to regulate an input of 24 V to
an output of 3.3 V at a fixed frequency of 400 kHz.
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. The LMS3655-Q1
enables a continuous load current of 5.5 A across the
wide input voltage range.
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.
Device Information⁽¹⁾
DEVICE NAME
PACKAGE
BODY SIZE
LMS3635-Q1
LMS3655-Q1
SON (22)
4.00 mm × 5.00 mm
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
VIN
3.5V to 36V
10µF
10µF
2.2µF
Typical Application Circuit
PVIN 1
PGND1
AVIN
VCC
AGND
NC
FPWM
EN
PVIN 2
PGND2
RESET
10µF
LMS3635/55
SYNC
CBIAS
FB
CBOOT
SW
0.1µF
470nF
L1=10µH
1
VOUT
3 X 47µF
LMS3635 and LMS3655 Efficiency: V_OUT = 5 V
100%
98%
96%
V_IN=12
94%
92%
90%
V_IN=24
88%
86%
84%
82%
80%
0.001
0.01
0.1
1
10
Output Current (A)
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. ADVANCE INFORMATION for pre-production products; subject to
change without notice.