MAX1830EEE ,3A / 1MHz / Low-Voltage / Step-Down Regulators with Synchronous Rectification and Internal SwitchesFeaturesThe MAX1830/MAX1831 constant-off-time, pulse-width- ±1.5% Output Accuracymodulated (PWM) s ..
MAX1830EEE+ ,3A, 1MHz, Low-Voltage, Step-Down Regulators with Synchronous Rectification and Internal SwitchesFeaturesThe MAX1830/MAX1831 constant-off-time, pulse-width-♦ ±1.5% Output Accuracymodulated (PWM) s ..
MAX1830EEE+T ,3A, 1MHz, Low-Voltage, Step-Down Regulators with Synchronous Rectification and Internal SwitchesApplications that forward bias the diode should take care not to exceed the IC’spackage power dissi ..
MAX1830EEE-T ,3A, 1MHz, Low-Voltage, Step-Down Regulators with Synchronous Rectification and Internal SwitchesELECTRICAL CHARACTERISTICS (continued)(V = V = +3.3V, FBSEL = GND, T = 0°C to +85°C, unless otherwi ..
MAX1830EEE-T ,3A, 1MHz, Low-Voltage, Step-Down Regulators with Synchronous Rectification and Internal SwitchesELECTRICAL CHARACTERISTICS(V = V = +3.3V, FBSEL = GND, T = 0°C to +85°C, unless otherwise noted. Ty ..
MAX1831EEE ,3A / 1MHz / Low-Voltage / Step-Down Regulators with Synchronous Rectification and Internal SwitchesApplications5V or 3.3V to Low-Voltage ConversionTypical ConfigurationCPU I/O SuppliesChipset Suppli ..
MAX4716EXK-T ,0.4 / Low-Voltage / Single-Supply SPST Analog Switches in SC70ELECTRICAL CHARACTERISTICS—Single +3V Supply(V+ = +2.7V to +3.6V, V = +1.4V, V = +0.5V, T = T to T ..
MAX4717EBC ,4.5Ω/20Ω, 300MHz Bandwidth, Dual SPDT Analog Switches in UCSPFeatures♦ USB 1.1 Signal Switching CompliantThe MAX4717/MAX4718 low-voltage, low on-resistance(TID ..
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MAX4717EBC-T ,4.5/20 om, 300 MHz bandwidth, dual SPDT analog switchApplicationsOrdering InformationUSB 1.1 Signal Switching CircuitsPIN/BUMP- TOPPART TEMP RANGEBatter ..
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MAX1830EEE-MAX1831EEE
3A / 1MHz / Low-Voltage / Step-Down Regulators with Synchronous Rectification and Internal Switches
MAX1830/MAX1831
3A, 1MHz, Low-Voltage, Step-Down Regulators with
Synchronous Rectification and Internal Switches19-2198; Rev 0; 10/01
General DescriptionThe MAX1830/MAX1831 constant-off-time, pulse-width-
modulated (PWM) step-down DC-DC converters are
ideal for use in 5V and 3.3V to low-voltage conversion
necessary in notebook and subnotebook computers.
These devices feature internal synchronous rectification
for high efficiency and reduced component count. They
require no external Schottky diode. The internal 45mΩ
PMOS power switch and 55mΩNMOS synchronous-rec-
tifier switch easily deliver continuous load currents up to
3A. The MAX1830 produces preset +2.5V, +1.8V, or
+1.5V output voltage or an adjustable output from +1.1V
to VIN. The MAX1831 produces preset +3.3V, +2.5V, and
+1.5V output voltages and an adjustable output from
+1.1V to VIN. They achieve efficiencies as high as 94%.
The MAX1830/MAX1831 use a unique current-mode,
constant-off-time, PWM control scheme, which includes
Idle Mode™ to maintain high efficiency during light-
load operation. The programmable constant-off-time
architecture sets switching frequencies up to 1MHz,
allowing the user to optimize performance trade-
offs between efficiency, output switching noise, compo-
nent size, and cost. Both devices are designed for con-
tinuous output currents up to 3A, an internal digital
soft-start to limit surge currents during startup, a 100%
duty cycle mode for low-dropout operation, and a
low-power shutdown mode that disconnects the input
from the output and reduces supply current below
1µA.The MAX1830/MAX1831 are available in 16-pin
QSOP packages.
For similar devices that provide continuous output
currents of 1A to 3A, refer to the MAX1644, MAX1623,
and MAX1742/MAX1842/MAX1843 data sheets.
Applications5V or 3.3V to Low-Voltage Conversion
CPU I/O Supplies
Chipset Supplies
Notebook and Subnotebook Computers
Features±1.5% Output Accuracy94% EfficiencyInternal PMOS/NMOS Switches
45mΩ/55mΩOn-Resistance at VIN= +4.5V
50mΩ/55mΩOn-Resistance at VIN= +3VOutput Voltages
+3.3V, +2.5V, or +1.5V Pin Selectable (MAX1831)
+2.5V, +1.8V, or +1.5V Pin Selectable (MAX1830)
+1.1V to VINAdjustable (Both Devices)+3V to +5.5V Input Voltage Range750µA (max) Operating Supply Current<1µA Shutdown Supply CurrentProgrammable Constant-Off-Time OperationUp to 1MHz Switching FrequencyIdle Mode Operation at Light LoadsThermal Shutdown Internal Digital Soft-Start Inrush Current Limiting100% Duty Cycle During Low-Dropout OperationOutput Short-Circuit Protection16-Pin QSOP PackageIdle Mode is a trademark of Maxim Integrated Products, Inc.
Typical Configuration
Pin Configuration appears at end of data sheet.
Ordering Information
MAX1830/MAX1831
3A, 1MHz, Low-Voltage, Step-Down Regulators with
Synchronous Rectification and Internal Switches
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICSStresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
VCC, IN, SHDNto GND............................................-0.3V to +6V
IN to VCC.............................................................................±0.3V
GND to PGND.....................................................................±0.3V
COMP, FB, TOFF, FBSEL, REF to GND.....-0.3V to (VCC+ 0.3V)
LX Current (Note 1)...............................................................5.1A
REF Short Circuit to GND Duration............................Continuous
ESD Protection.....................................................................±2kV
Continuous Power Dissipation (TA= +70°C)
16-Pin QSOP (derate 14mW/°C above +70°C;
part mounted on 1in2of 1oz copper).............................1.12W
Operating Temperature Range...........................-40°C to +85°C
Storage Temperature Range.............................-65°C to +150°C
Junction Temperature......................................................+150°C
Lead Temperature (soldering, 10s)................................+300°C
Note 1:LX has internal clamp diodes to PGND and IN. Applications that forward bias the diode should take care not to exceed the IC’s
package power dissipation.
MAX1830/MAX1831
3A, 1MHz, Low-Voltage, Step-Down Regulators with
Synchronous Rectification and Internal Switches
ELECTRICAL CHARACTERISTICS (continued)
ELECTRICAL CHARACTERISTICS
MAX1830/MAX1831
3A, 1MHz, Low-Voltage, Step-Down Regulators with
Synchronous Rectification and Internal Switches
Typical Operating Characteristics(Circuit of Figure 1, TA = +25°C, unless otherwise noted.)
ELECTRICAL CHARACTERISTICS (continued)(VIN= VCC= +3.3V, FBSEL = GND, TA
= -40°C to +85°C, unless otherwise noted.) (Note 5)
Note 2:Not production tested.
Note 3:Soft-start time is measured with respect to the number of cycles on LX.
Note 4:This is a metal migration limit. Maximum output current may be limited by thermal capability to a lower value than this.
Note 5:Specifications from 0°C to -40°C are guaranteed by design, not production tested.
MAX1830/MAX1831
3A, 1MHz, Low-Voltage, Step-Down Regulators with
Synchronous Rectification and Internal SwitchesNORMALIZED OUTPUT ERROR
vs. OUTPUT CURRENT
MAX1830 toc04
OUTPUT CURRENT (A)
NORMALIZED OUTPUT ERROR (%)
SWITCHING FREQUENCY
vs. OUTPUT CURRENT
MAX1830 toc05
OUTPUT CURRENT (A)
FREQUENCY (kHz)
400µs/div
STARTUP AND SHUTDOWNVSHDN
5V/div
IIN
1A/div
VOUT
1V/div
MAX1830 toc06
VIN = 3.3V, VOUT = 1.5V,
ROUT = 0.5Ω, RTOFF = 82kΩ, L = 1.5µH
ypical Operating Characteristics (continued)(Circuit of Figure 1, TA = +25°C, unless otherwise noted.)
MAX1830/MAX1831
3A, 1MHz, Low-Voltage, Step-Down Regulators with
Synchronous Rectification and Internal Switches
_______________Detailed DescriptionThe MAX1830/MAX1831 synchronous, current-mode,
constant-off-time, PWM DC-DC converters step down
input voltages of +3V to +5.5V to preset output voltages,
or to an adjustable output voltage from +1.1V to VIN. The
MAX1830 has preset outputs +2.5V, +1.8V, and +1.5V.
The MAX1831 has preset outputs of +3.3V, +2.5V or
+1.5V. Both devices deliver up to 3A of continuous output
current. Internal switches composed of a 45mΩPMOS
power switch and a 55mΩNMOS synchronous rectifier
switch improve efficiency, reduce component count, and
eliminate the need for an external Schottky diode.
The MAX1830/MAX1831 optimize efficiency by operat-
ing in constant-off-time mode under heavy loads and in
Maxim’s proprietary Idle Mode under light loads. A sin-
gle resistor-programmable constant-off-time control
sets switching frequencies up to 1MHz, allowing the
user to optimize performance trade-offs in efficiency,
switching noise, component size, and cost. Under low-
dropout conditions, the device operates in a 100%
duty-cycle mode, where the PMOS switch remains con-
tinuously on. Idle Mode enhances light-load efficiency
by skipping cycles, thus reducing transition and gate-
charge losses.
When power is drawn from a regulated supply, constant-
off-time PWM architecture essentially provides constant-
frequency operation. This architecture has the inherent
advantage of quick response to line and load transients.
The MAX1830/MAX1831 current-mode, constant-off-
time PWM architecture regulates the output voltage by
changing the PMOS switch on-time relative to the con-
stant off-time. Increasing the on-time increases the
peak inductor current and the amount of energy trans-
ferred to the load per pulse.
Modes of OperationThe current through the PMOS switch determines the
mode of operation: constant-off-time mode (for load
currents greater than half the Idle Mode threshold), or
Idle Mode (for load currents less than half the Idle
Mode threshold). Current sense is achieved through a
proprietary architecture that eliminates current-sensing2R losses.
Constant-Off-Time ModeConstant-off-time operation occurs when the current
through the PMOS switch is greater than the Idle Mode
threshold current (which corresponds to a load current
of half the Idle Mode threshold). In this mode, the regu-
MAX1830/MAX1831
3A, 1MHz, Low-Voltage, Step-Down Regulators with
Synchronous Rectification and Internal Switcheslation comparator turns the PMOS switch on at the end
of each off-time, keeping the device in continuous-con-
duction mode. The PMOS switch remains on until the
output is in regulation or the current limit is reached.
When the PMOS switch turns off, it remains off for the
programmed off-time (tOFF). To control the current
under short-circuit conditions, the PMOS switch
remains off for approximately 4 x tOFFwhen VOUT<
VOUT(NOM) / 4.
Idle ModeUnder light loads, the devices improve efficiency by
switching to a pulse-skipping Idle Mode. Idle Mode
operation occurs when the current through the PMOS
switch is less than the Idle Mode threshold current. Idle
Mode forces the PMOS to remain on until the current
through the switch reaches the Idle Mode threshold,
thus minimizing the unnecessary switching that
degrades efficiency under light loads. In Idle Mode, the
Figure 2. Functional Diagram
Figure 1. Typical Circuit
