19-3518; Rev 1; 8/05
Multi-Output, Low-Noise Power-Supply
Controllers for Notebook Computers
________________General Description ____________________________Features
The MAX1630A–MAX1635A are buck-topology, step- ♦ 96% Efficiency
down, switch-mode, power-supply controllers that gener- ♦ +4.2V to +30V Input Range
ate 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-com-
♦ 2.5V to 5.5V Dual Adjustable Outputs
♦ Selectable 3.3V and 5V Fixed or Adjustable
Outputs (Dual Mode™)
♦ 12V Linear Regulator
pensation networks, and automatic bootstrapping.
Up to 96% efficiency is achieved through synchronous
rectification and Maxim’s proprietary Idle Mode™ control
♦ Adjustable Secondary Feedback
♦ 5V/50mA Linear Regulator Output
scheme. Efficiency is greater than 80% over a 1000:1 ♦ Precision 2.5V Reference Output
load-current range, which extends battery life in system- ♦ Programmable Power-Up Sequencing
suspend or standby mode. Excellent dynamic response ♦ Power-Good (RESET) Output
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
♦ Output Overvoltage Protection
n-channel MOSFET switching.
♦ Output Undervoltage Shutdown
These devices feature a logic-controlled and synchroniz-
able, fixed-frequency, pulse-width-modulation (PWM)
♦ 200kHz/300kHz Low-Noise, Fixed-Frequency
operating mode. This reduces noise and RF interference
in sensitive mobile communications and pen-entry appli-
♦ Low-Dropout, 99% Duty-Factor Operation
cations. Asserting the SKIP pin enables fixed-frequency
mode for lowest noise under all load conditions.
www.DataSheet4U.comThe MAX1630A–MAX1635A include two PWM regulators,
♦ 2.5mW Typical Quiescent Power (+12V Input,
Both SMPSs On)
♦ 4µA Typical Shutdown Current
adjustable from 2.5V to 5.5V with fixed 5.0V and 3.3V ♦ 28-Pin SSOP Package
modes. All these devices include secondary feedback
regulation, and the MAX1630A/MAX1632A/MAX1633A/
MAX1635A each contain 12V/120mA linear regulators.
The MAX1631A/MAX1634A include a secondary feed-
back input (SECFB), plus a control pin (STEER) that
-40°C to +85°C
selects which PWM (3.3V or 5V) receives the secondary +Denotes lead-free package.
feedback signal. SECFB provides a method for adjusting Ordering Information continued at end of data sheet.
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 MAX1630A/MAX1631A/MAX1632A contain internal
output overvoltage and undervoltage protection features.
The MAX1630A family has improved RF immunity over
the MAX1630 family.
Notebook and Subnotebook Computers
PDAs and Mobile Communicators
Desktop CPU Local DC-DC Converters
Pin Configurations and Selector Guide appear at end of data
Idle Mode and Dual Mode are trademarks of Maxim Integrated
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.