MAX15014_07 Datasheet, PDF (1/26 Pages) Maxim Integrated Products – 1A, 4.5V to 40V Input Buck Converters with 50mA Auxiliary LDO Regulators

19-0734; Rev 0; 1/07
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1A, 4.5V to 40V Input Buck Converters with
50mA Auxiliary LDO Regulators
General Description
The MAX15014–MAX15017 combine a step-down DC-
DC converter and a 50mA, low-quiescent-current low-
dropout (LDO) regulator. The LDO regulator is ideal for
powering always-on circuitry in automotive applications.
The DC-DC converter input voltage range is 4.5V to 40V
for the MAX15015/MAX15016, and 7.5V to 40V for the
MAX15014/MAX15017.
The DC-DC converter output is adjustable from 1.26V to
32V and can deliver up to 1A of load current. These
devices utilize a feed-forward voltage-mode control
scheme for good noise immunity in the high-voltage
switching environment and offer external compensation
allowing for maximum flexibility with a wide selection of
inductor values and capacitor types. The switching
frequency is internally fixed at 135kHz and 500kHz,
depending on the version chosen. Moreover, the
switching frequency can be synchronized to an exter-
nal clock signal through the SYNC input. Light load effi-
ciency is improved by automatically switching to a
pulse-skip mode. The soft-start time is adjustable with
an external capacitor. The DC-DC converter can be
disabled independent of the LDO, thus reducing the
quiescent current to 47µA (typ).
The LDO linear regulators operate from 5V to 40V and
deliver a guaranteed 50mA load current. The devices
feature a preset output voltage of 5V (MAX1501_A) or
3.3V (MAX1501_B). Alternatively, the output voltage
can be adjusted from 1.5V to 11V by using an external
resistive divider. The LDO section also features a
RESET output with adjustable timeout period.
Protection features include cycle-by-cycle current limit,
hiccup-mode output short-circuit protection, and thermal
shutdown. All devices are available in a space-saving,
high-power (2.86W), 36-pin TQFN package and are
rated for operation over the -40°C to +125°C automotive
temperature range.
Applications
Car Radios
Automotive Body Control Modules
Automotive Instrument Cluster
Navigation Systems
Features
o Combined DC-DC Converters and Low-Quiescent-
Current LDO Regulators
o 1A DC-DC Converters Operate from 4.5V to 40V
(MAX15015/MAX15016) or 7.5V to 40V
(MAX15014/MAX15017)
o Switching Frequency of 135kHz
(MAX15014/MAX15016) or 500kHz
(MAX15015/MAX15017)
o 50mA LDO Regulator Operates from 5V to 40V
Independent of the DC-DC Converter
o 47µA Quiescent Current with DC-DC Converter
Off and LDO On
o 6µA System Shutdown Current
o Frequency Synchronization Input
o Shutdown/Enable Inputs
o Adjustable Soft-Start Time
o Active-Low Open-Drain RESET Output with
Programmable Timeout Delay
o Thermal Shutdown and Output Short-Circuit
Protection
o Space-Saving (6mm x 6mm) Thermally Enhanced
36-Pin TQFN Package
Ordering Information
PART
TEMP RANGE ^PIN-
PACKAGE
PKG
CODE
MAX15014AATX+ -40°C to +125°C 36 TQFN-EP* T3666-3
MAX15014BATX+ -40°C to +125°C 36 TQFN-EP* T3666-3
MAX15015AATX+ -40°C to +125°C 36 TQFN-EP* T3666-3
MAX15015BATX+ -40°C to +125°C 36 TQFN-EP* T3666-3
MAX15016AATX+ -40°C to +125°C 36 TQFN-EP* T3666-3
MAX15016BATX+ -40°C to +125°C 36 TQFN-EP* T3666-3
MAX15017AATX+ -40°C to +125°C 36 TQFN-EP* T3666-3
MAX15017BATX+ -40°C to +125°C 36 TQFN-EP* T3666-3
+Denotes a lead-free package.
*EP = Exposed pad.
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