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MAX1831EEE+T

P1-P3P4-P6P7-P9P10-P12P13-P13
MAX1830/MAX1831
3A, 1MHz, Low-Voltage, Step-Down Regulators with
Synchronous Rectification and Internal Switches
________________________________________________________________ Maxim Integrated Products 1
19-2198; Rev 0; 10/01
General Description
The 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 55mΩ NMOS 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 V
IN
. The MAX1831 produces preset +3.3V, +2.5V, and
+1.5V output voltages and an adjustable output from
+1.1V to V
IN.
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.
Applications
5V or 3.3V to Low-Voltage Conversion
CPU I/O Supplies
Chipset Supplies
Notebook and Subnotebook Computers
Features
♦ ±1.5% Output Accuracy
♦ 94% Efficiency
♦ Internal PMOS/NMOS Switches
45mΩ/55mΩ On-Resistance at V
IN
= +4.5V
50mΩ/55mΩ On-Resistance at V
IN
= +3V
♦ Output Voltages
+3.3V, +2.5V, or +1.5V Pin Selectable (MAX1831)
+2.5V, +1.8V, or +1.5V Pin Selectable (MAX1830)
+1.1V to V
IN
Adjustable (Both Devices)
♦ +3V to +5.5V Input Voltage Range
♦ 750µA (max) Operating Supply Current
♦ <1µA Shutdown Supply Current
♦ Programmable Constant-Off-Time Operation
♦ Up to 1MHz Switching Frequency
♦ Idle Mode Operation at Light Loads
♦ Thermal Shutdown
♦ Internal Digital Soft-Start Inrush Current Limiting
♦ 100% Duty Cycle During Low-Dropout Operation
♦ Output Short-Circuit Protection
♦ 16-Pin QSOP Package
Idle Mode is a trademark of Maxim Integrated Products, Inc.
Typical Configuration
TOFF
COMP
V
CC
FBSEL
SHDN
IN
PGND
GND
REF
LX
FB
MAX1830
MAX1831
OUTPUT
+1.1V TO
V
IN
INPUT
+3V TO
+5.5V
EVALUATION KIT
AVAILABLE
Pin Configuration appears at end of data sheet.
PART
MAX1830EEE
-40°C to +85°C
TEMP. RANGE PIN-PACKAGE
16 QSOP
Ordering Information
MAX1831EEE
-40°C to +85°C 16 QSOP
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.
MAX1830/MAX1831
3A, 1MHz, Low-Voltage, Step-Down Regulators with
Synchronous Rectification and Internal Switches
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V
IN
= V
CC
= +3.3V, FBSEL = GND, T
A
= 0°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C.)
Stresses 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.
V
CC
, IN, SHDN to GND ............................................-0.3V to +6V
IN to V
CC
.............................................................................±0.3V
GND to PGND.....................................................................±0.3V
COMP, FB, TOFF, FBSEL, REF to GND .....-0.3V to (V
CC
+ 0.3V)
LX Current (Note 1) ...............................................................5.1A
REF Short Circuit to GND Duration ............................Continuous
ESD Protection .....................................................................±2kV
Continuous Power Dissipation (T
A
= +70°C)
16-Pin QSOP (derate 14mW/°C above +70°C;
part mounted on 1in
2
of 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
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Input Voltage V
IN
, V
CC
3.0 5.5 V
FBSEL = V
CC
2.487 2.525 2.563
FBSEL =
unconnected
1.492 1.515 1.538
FBSEL = REF
(MAX1830)
1.791 1.818 1.845
V
IN
= +3V to +5.5V,
I
LOAD
= 0 to 3A,
V
FB
= V
OUT
FBSEL = GND 1.084 1.100 1.117
Preset Output Voltage V
OUT
V
IN
= +3.7V to +5.5V,
I
LOAD
= 0 to 3A,
V
FB
= V
OUT
FBSEL = REF
(MAX1831)
3.283 3.333 3.383
V
Adjustable Output Voltage Range
V
CC
= V
IN
= +3V to +5.5V, I
LOAD
= 0,
FBSEL = GND
V
REF
V
IN
V
AC Load Regulation Error 2%
DC Load Regulation Error 0.4 %
Dropout Voltage V
DO
V
CC
= V
IN
= +3V, I
LOAD
= 3A 150 330 mV
Reference Voltage V
REF
1.089 1.100 1.111 V
Reference Load Regulation ∆V
REF
I
REF
= -1µA to +10µA 0.5 2 mV
Current-Limit Threshold I
LIMIT
4.0 4.8 5.4 A
Maximum Output RMS Current I
OUT
(
RMS
)
(Note 4) 3.4 A
Idle Mode Current Threshold I
IM
0.2 0.6 1.0 A
V
IN
= 4.5V 45 90
PMOS Switch On-Resistance R
ON
,
P
I
LX
= 0.5A
V
IN
= 3V 50 110
V
IN
= 4.5V 55 95
NMOS Switch On-Resistance R
ON
,
N
I
LX
= 0.5A
V
IN
= 3V 55 100
mΩ
Switching Frequency f (Note 2) 1 MHz
No-Load Supply Current I
IN
+ I
CC
V
FB
= 1.2V 325 750 µA
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
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= V
CC
= +3.3V, FBSEL = GND, T
A
= 0°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C.)
ELECTRICAL CHARACTERISTICS
(V
IN
= V
CC
= +3.3V, FBSEL = GND, T
A
= -40°C to +85°C, unless otherwise noted.) (Note 5)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Input Voltage V
IN
, V
CC
3.0 5.5 V
FBSEL = V
CC
2.475 2.575
FBSEL =
unconnected
1.485 1.545
FBSEL = REF
(MAX1830)
1.782 1.854
V
IN
= +3V to +5.5V,
I
LOAD
= 0 to 3A,
V
FB
= V
OUT
FBSEL = GND 1.078 1.122
Preset Output Voltage V
OUT
V
IN
= +3.7V to +5.5V,
I
LOAD
= 0 to 3A,
V
FB
= V
OUT
FBSEL = REF
(MAX1831)
3.267 3.399
V
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
SHDN = GND, into V
CC
and IN pins; LX = 0
or 3.3V
0.2 20
SHDN = GND, into IN with LX = 0 0.2 20
Shutdown Supply Current
SHDN = GND, into IN with LX = 3.3V 0.1 20
µA
Thermal Shutdown Threshold T
SHDN
Hysteresis = 15°C 165 °C
Undervoltage Lockout Threshold V
UVLO
V
IN
falling, hysteresis = 90mV 1.8 2.6 2.8 V
FB Input Bias Current I
FB
V
FB
= 1.2V 0 70 300 nA
R
TOFF
= 110kΩ 0.85 1.00 1.15 µs
R
TOFF
= 44kΩ 0.3 0.4 0.5 µsOff-Time t
OFF
R
TOFF
= 440kΩ 3.0 3.9 5.0 µs
Startup Off-Time 4
✕
t
OFF
µs
Minimum On-Time t
ON
(Note 2) 0.40 µs
Soft-Start Time (Note 3) 3
✕
256 cycles
SHDN Input Current I
SHDN
SHDN = 0 or V
CC
-0.5 0.5 µA
SHDN Logic Input Low Voltage V
IL
0.8 V
SHDN Logic Input High Voltage V
IH
2.0 V
FBSEL Input Current -5 5 µA
FBSEL = GND 0.2 V
FBSEL = REF 0.9 1.3 V
FBSEL = unconnected
0.7
✕
V
CC
- 0.2
0.7
✕
V
CC
+ 0.2
V
FBSEL Logic Thresholds
FBSEL = V
CC
V
CC
- 0.2 V
CC
+ 0.2 V
P1-P3P4-P6P7-P9P10-P12P13-P13

MAX1831EEE+T

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Buy MAX1831EEE+T
Manufacturer:
Maxim Integrated
Description:
Switching Voltage Regulators 3A 1MHz Step-Down
Lifecycle:
New from this manufacturer.
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