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概述
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The MAX1630–MAX1635 are buck-topology, step-down,
switch-mode, power-supply controllers that generate
logic-supply voltages in battery-powered systems. These
high-performance, dual/triple-output devices include on-board
power-up sequencing, power-good signaling with
delay, digital soft-start, secondary winding control, low-dropout
circuitry, internal frequency-compensation networks,
and automatic bootstrapping.
Up to 96% efficiency is achieved through synchronous
rectification and Maxim's proprietary Idle Mode™ control
scheme. Efficiency is greater than 80% over a 1000:1
load-current range, which extends battery life in system-suspend
or standby mode. Excellent dynamic response
corrects output load transients caused by the latest
dynamic-clock CPUs within five 300kHz clock cycles.
Strong 1A on-board gate drivers ensure fast external
N-channel MOSFET switching.
These devices feature a logic-controlled and synchronizable,
fixed-frequency, pulse-width-modulation (PWM)
operating mode. This reduces noise and RF interference
in sensitive mobile communications and pen-entry applications.
Asserting the active-low SKIP pin enables fixed-frequency
mode, for lowest noise under all load conditions.
The MAX1630–MAX1635 include two PWM regulators,
adjustable from 2.5V to 5.5V with fixed 5.0V and 3.3V
modes. All these devices include secondary feedback
regulation, and the MAX1630/MAX1632/MAX1633/
MAX1635 each contain 12V/120mA linear regulators. The
MAX1631/MAX1634 include a secondary feedback input
(SECFB), plus a control pin (STEER) that selects which
PWM (3.3V or 5V) receives the secondary feedback signal.
SECFB provides a method for adjusting the secondary
winding voltage regulation point with an external
resistor divider, and is intended to aid in creating auxiliary
voltages other than fixed 12V.
The MAX1630/MAX1631/MAX1632 contain internal output
overvoltage and undervoltage protection features.
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