MAX1818EUT33+T ,500mA, Low-Dropout Linear Regulator in SOT23ELECTRICAL CHARACTERISTICS(V = V + 500mV or V = +2.5V, whichever is greater; SHDN = IN, T = -40°C t ..
MAX181ACPL+ ,Complete, 100ksps, 8-Channel, 12-Bit Data Acquisition Systems19-3950; Rev 0; 6/91
MAX181ACPL+ ,Complete, 100ksps, 8-Channel, 12-Bit Data Acquisition SystemsApplications
High-Speed Servo Loops
Digital-Signal Processing
High-Accuracy Process Control
A ..
MAX1820XEBC ,WCDMA Cellular Phone 600mA Buck RegulatorsELECTRICAL CHARACTERISTICS(V = 3.6V, SHDN = BATT, SKIP = SYNC = GND, V = 1.25V (MAX1820 only), T = ..
MAX1820XEBC+T ,WCDMA Cellular Phone 600mA Buck RegulatorsApplications4.7μHINPUT DYNAMICWCDMA Cell Phone Power Amplifiers2.6V TO OUTPUTBATT LX5.5V 0.4V TO 3. ..
MAX1820XEBC+T ,WCDMA Cellular Phone 600mA Buck RegulatorsFeaturesThe MAX1820/MAX1821 low-dropout, pulse-width-mod-♦ Dynamically Adjustable Output from 0.4V ..
MAX468CPE ,Two-Channel, Triple/Quad RGB Video Switches and BuffersGeneral Description ________
MAX468EPE ,Two-Channel, Triple/Quad RGB Video Switches and BuffersMAX463–MAX47019-0219; Rev 2; 6/94Two-Channel, Triple/QuadRGB Video Switches and Buffers____________ ..
MAX4690CAE ,1.25 / Dual SPST / CMOS Analog SwitchesFeaturesThe MAX4680/MAX4690/MAX4700 dual analog switches♦ Low On-Resistance (1.25Ω max)feature low ..
MAX4690CAE+ ,1.25Ω, Dual, SPST, CMOS Analog SwitchELECTRICAL CHARACTERISTICS—Dual Supplies(V+ = +15V, V- = -15V, V = +5V, V = +2.4V, V = +0.8V, T = T ..
MAX4690CWE ,1.25 / Dual SPST / CMOS Analog Switchesfeatures guaranteed break-before-make switching.These devices operate from a +4.5V to +36V singlesu ..
MAX4690EAE ,1.25 / Dual SPST / CMOS Analog SwitchesFeaturesThe MAX4680/MAX4690/MAX4700 dual analog switches♦ Low On-Resistance (1.25Ω max)feature low ..
MAX1818EUT15#TG16-MAX1818EUT15-T-MAX1818EUT18#G16-MAX1818EUT18#TG16-MAX1818EUT18+T-MAX1818EUT18-T-MAX1818EUT25#G16-MAX1818EUT25#TG16-MAX1818EUT25+-MAX1818EUT25+T-MAX1818EUT25-T-MAX1818EUT33#G16-MAX1818EUT33#TG16-MAX1818EUT33+T
500mA, Low-Dropout Linear Regulator in SOT23
General DescriptionThe MAX1818 low-dropout linear regulator operates
from a +2.5V to +5.5V supply and delivers a guaran-
teed 500mA load current with low 120mV dropout. The
high-accuracy (±1%) output voltage is preset at an
internally trimmed voltage (see Selector Guide) or can
be adjusted from 1.25V to 5.0V with an external resis-
tive divider.
An internal PMOS pass transistor allows the low 125µA
supply current to remain independent of load, making
this device ideal for portable battery-operated equip-
ment such as personal digital assistants (PDAs), cellu-
lar phones, cordless phones, base stations, and
notebook computers.
Other features include an active-low open-drain reset
output that indicates when the output is out of regula-
tion, a 0.1µA shutdown, short-circuit protection, and
thermal shutdown protection. The device is available in
a miniature 800mW 6-pin SOT23 package.
ApplicationsNotebook Computers
Cellular and Cordless Telephones
Personal Digital Assistants (PDAs)
Palmtop Computers
Base Stations
USB Hubs
Docking Stations
FeaturesGuaranteed 500mA Output CurrentLow 120mV Dropout at 500mA±1% Output Voltage Accuracy
Preset at 1.5V, 1.8V, 2.0V, 2.5V, 3.3V, 5V
Adjustable from 1.25V to 5.0VPower OK OutputLow 125µA Ground Current0.1µA Shutdown CurrentThermal Overload ProtectionOutput Current LimitTiny 800mW 6-Pin SOT23 Package
MAX1818
500mA Low-Dropout
Linear Regulator in SOT23 19-1860; Rev 2; 6/08
Ordering Information*Insert the desired two-digit suffix (see Selector Guide) into the
blanks to complete the part number.
PART*TEMP RANGEPIN-PACKAGEMAX1818EUT_ _-T-40°C to +85°C6 SOT23
MAX1818EUT_ _#T-40°C to +85°C6 SOT23
Typical Operating CircuitMAX1818
OFF
CIN
1μF
SHDN
OUT
POK
GNDSET
COUT
3.3μF
VOUT
TO
VIN = 2.5V TO 5.5V
RPOK
100k
Pin ConfigurationPOK
GNDSHDNOUTSET
MAX1818
SOT23TOP VIEW
Note:The MAX1818 requires a special solder temperature
profile described in the Absolute Maximum Ratings section.
T = Tape and reel.
#Denotes an RoHS-compliant package.
Selector Guide appears at end of data sheet.
MAX1818
500mA Low-Dropout
Linear Regulator in SOT23
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(VIN= VOUT+ 500mV or VIN= +2.5V, whichever is greater; SHDN= IN, TA= -40°C to +85°C, unless otherwise noted. Typical values
are at TA= +25°C.) (Note 3)
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.
IN,SHDN,POK, SET to GND...................................-0.3V to +6V
OUT to GND................................................-0.3V to (VIN+ 0.3V)
Output Short-Circuit Duration...............................................1min
Continuous Power Dissipation (TA= +70°C) (Note 1)
6-Pin SOT23 (derate 10mW/°C above +70°C)..............800mW
Operating Temperature Range...........................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10s) (Note 2)...................+300°C
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSInput VoltageVIN2.55.5V
Input Undervoltage Lock-OutVUVLORising, 75mV hysteresis2.02.152.3V
IOUT = 100mA, TA = +25°C, VOUT ≥ 2.0V-1+1
IOUT = 100mA, VOUT < 2.0V-1.5+1.5
IOUT = 100mA, TA = -40°C to +85°C-2.5+2.5Output Voltage Accuracy
(Preset Mode)VOUT
IOUT = 1mA to 500mA, VIN > VOUT + 0.5V,
TA = -40°C to +85°C-3+3
Adjustable Output Voltage
Range1.255V
TA = 0°C to +85°C1.2251.2501.275SET Voltage Threshold
(Adjustable Mode)VSET
VIN = 2.7V,
IOUT = 100mA,
VOUT set to 2.0VTA = -40°C to +85°C1.2131.288
Guaranteed Output Current
(RMS)IOUTVIN ≥ 2.7V500mA
Short-Circuit Current LimitILIMVOUT = 0, VIN ≥ 2.7V0.550.81.8A
In-Regulation Current LimitVOUT > 96% of nominal value, VIN ≥ 2.7V1.6A
SET Dual Mode™ Threshold50100150mV
SET Input Bias CurrentISETVSET = 1.25V-100+100nA
IOUT = 100µA125250Ground-Pin CurrentIQIOUT = 500mA140µA
VOUT = 5V100220
VOUT = 3.3V120215Dropout Voltage (Note 4)VIN - VOUTIOUT = 500mA
VOUT = 2.5V210360
Line RegulationΔVLNRVIN from (VOUT + 100mV) to 5.5V,
ILOAD = 5mA-0.150+0.15%/V
Note 1:Thermal properties are specified with product mounted on PC board with one square-inch of copper area and still air. With
minimal copper, the SOT23 package dissipates 712mW at +70°C. With a quarter square inch of copper, it will dissipate
790mW at +70°C. Copper should be equally shared between the IN, OUT, and GND pins.
Note 2:This device is constructed using a unique set of packaging techniques that imposes a limit on the thermal profile to which
the device can be exposed during board-level solder attach and rework. The limit permits only the use of the solder profiles
recommended in the industry standard specification, IPC JEDEC-J-STD-020A, paragraph 7.6, Table 3 for the IR/VPR and
convection reflow. Preheating is required. Hand or wave soldering is not allowed.
MAX1818
500mA Low-Dropout
Linear Regulator in SOT23
ELECTRICAL CHARACTERISTICS (continued)(VIN= VOUT+ 500mV or VIN= +2.5V, whichever is greater; SHDN= IN, TA= -40°C to +85°C, unless otherwise noted. Typical values
are at TA= +25°C.) (Note 3)
Note 3:All devices are 100% production tested at TA= +25°C. Limits over the operating temperature range are guaranteed by
design.
Note 4:The Dropout Voltage is defined as VIN- VOUT, when VOUTis 100mV below the value of VOUTmeasured for VIN= VOUT(NOM)
+ 500mV. Since the minimum input voltage is 2.5V, this specification is only meaningful when VOUT(NOM)> 2.5V. For
VOUT(NOM)between 2.5V and 3.5V, use the following equations: Typical Dropout = -93mV/V ✕VOUT(NOM)+ 445mV;
Guaranteed Maximum Dropout = -137mV/V ✕VOUT(NOM)+7004mV. For VOUT(NOM)> 3.5V, Typical Dropout = 120mV;
Maximum Dropout = 220mV.
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSLoad RegulationΔVLDRIOUT = 1mA to 500mA0.41.0%
Output Voltage Noise10Hz to 1MHz, COUT = 3.3µF (ESR < 0.1Ω)115µVRMS
SHUTDOWNShutdown Supply CurrentIOFFSHDN = GND, VIN = 5.5V0.115µA
VIH2.5V < VIN < 5.5V1.6SHDN Input ThresholdVIL2.5V < VIN < 5.5V0.6V
SHDN = IN or GND, TA = +25°C125SHDN Input Bias CurrentI SHDNTA = +85°C5nA
POK OUTPUTPOK Output Low VoltageVOLPOK sinking 1mA0.010.1V
Operating Voltage Range for
Valid POKPOK sinking 100µA1.05.5V
POK = 5.5V, TA = +25°C125POK Output High Leakage
CurrentTA = +85°C5nA
POK ThresholdRising edge, referred to VOUT(NOMINAL)909396%
THERMAL PROTECTIONThermal Shutdown TemperatureTSHDN170°C
Thermal Shutdown HysteresisΔTSHDN20°C
Typical Operating Characteristics(VIN = (VOUT+ 500mV) or +2.5V, whichever is greater; SHDN= IN, CIN= 1µF, COUT= 3.3µF, TA= +25°C, unless otherwise noted.)
GROUND PIN CURRENT
vs. INPUT VOLTAGE
MAX1818 toc01
GROUND PIN CURRENT (
ILOAD = 150mA
3.3V OUTPUT
2.5V OUTPUT
1.8V OUTPUT
MAX1818 toc02
GROUND PIN CURRENT (
GROUND PIN CURRENT
vs. LOAD CURRENT3.3V OUTPUT
2.5V OUTPUT
1.8V OUTPUT
MAX1818 toc03
GROUND PIN CURRENT (
GROUND PIN CURRENT
vs. TEMPERATURE1.5V OUTPUT
5.0V OUTPUT
ILOAD = 150mA
MAX1818
500mA Low-Dropout
Linear Regulator in SOT23
Typical Operating Characteristics (continued)(VIN = (VOUT+ 500mV) or +2.5V, whichever is greater; SHDN= IN, CIN= 1µF, COUT= 3.3µF, TA= +25°C, unless otherwise noted.)
MAX1818 toc04
LOAD CURRENT (A)
DROPOUT VOLTAGE (mV)
VOUT = 3.3V
DROPOUT VOLTAGE
vs. LOAD CURRENTTA = +85°C
TA = +25°C
TA = -40°C
MAX1818 toc05
LOAD CURRENT (A)
OUTPUT VOLTAGE ACCURACY (%)0.20.30.40.10.50.60.70.90.81.0
OUTPUT VOLTAGE ACCURACY
vs. LOAD CURRENT3.3V OUTPUT
2.5V OUTPUT
1.8V OUTPUT
MAX1818 toc06
TEMPERATURE (°C)
OUTPUT VOLTAGE ACCURACY (%)
OUTPUT VOLTAGE ACCURACY
vs. TEMPERATUREVOUT = 1.5V TO 5.0VILOAD = 150mA
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCYMAX1818 toc07
PSRR (dB)
FREQUENCY (kHz)
COUT = 3.3μF
VOUT = 3.3V
RLOAD = 100Ω
LINE TRANSIENTMAX1818 toc08
VIN
VOUT
2.5V10mV/div
3.5V
100μs/div
500mV/div
LOAD-TRANSIENT RESPONSEMAX1818 toc09
IOUT
VOUT
500mA
100mA
20mV/div
40μs/div
VIN = 3.3V
VOUT = 2.5V
LOAD-TRANSIENT RESPONSE
NEAR DROPOUTMAX1818 toc10
OUT
100mV/div
200mA
IOUT
10μs/div
VIN = VOUT + 100mV
VOUT = 3.3V
POWER-ON RESETMAX1818 toc11
VIN
VPOK
VOUT
2V/div
10ms/div
MAX1818
500mA Low-Dropout
Linear Regulator in SOT23
SHUTDOWN WAVEFORMMAX1818 toc12
POK
SHUTDOWN
VOLTAGE
VOUT
2V/div
200μs/div
SHORT-CIRCUIT CURRENT LIMIT
vs. SUPPLY VOLTAGE
MAX1818 toc13
SUPPLY VOLTAGE (V)
SHORT-CIRCUIT CURRENT LIMIT (A)
VOUT(NOM) = +2V
Detailed DescriptionThe MAX1818 is a low-dropout, low-quiescent-current
linear regulator designed primarily for battery-powered
applications. The device supplies loads up to 500mA
and is available with preset output voltages. As illustrat-
ed in Figure 1, the MAX1818 consists of a 1.25V refer-
ence, error amplifier, P-channel pass transistor, and
internal feedback voltage-divider.
The 1.25V reference is connected to the error amplifier,
which compares this reference with the feedback volt-
age and amplifies the difference. If the feedback volt-
age is lower than the reference voltage, the
pass-transistor gate is pulled lower, which allows more
current to pass to the output and increases the output
voltage. If the feedback voltage is too high, the pass-
transistor gate is pulled up, allowing less current to
pass to the output.
The output voltage is fed back through either an inter-
nal resistive divider connected to OUT or an external
resistor network connected to SET. The Dual Mode
comparator examines VSETand selects the feedback
path. If VSETis below 50mV, the internal feedback path
is used and the output is regulated to the factory-preset
voltage.
Pin Description
PINNAMEFUNCTION1INRegulator Input. Supply voltage can range from 2.5V to 5.5V. Bypass with a 1μF capacitor to GND (see
Capacitor Selection and Regulator Stability).POKOpen-Drain POK Output. POK remains low while the output voltage (VOUT) is below the POK threshold.
Connect a 100kΩ pull-up resistor from POK to OUT to obtain an output voltage.SHDNActive-Low Shutdown Input. A logic low reduces supply current below 15μA. In shutdown, the POK output is
low, and OUT is high impedance. Connect to IN for normal operation.GNDGroundSETVoltage-Setting Input. Connect to GND for preset output. Connect to a resistive voltage-divider between
OUT and GND to set the output voltage between 1.25V and 5.0V.OUTRegulator Output. Sources up to 500mA. Bypass with a 3.3μF low-ESR capacitor to GND. Use a 4.7μF
capacitor for output voltages below 2V.
Typical Operating Characteristics (continued)(VIN = (VOUT+ 500mV) or +2.5V, whichever is greater; SHDN= IN, CIN= 1µF, COUT= 3.3µF, TA= +25°C, unless otherwise noted.)
MAX1818
500mA Low-Dropout
Linear Regulator in SOT23Additional blocks include an output current limiter, ther-
mal sensor, and shutdown logic.
Internal P-Channel Pass TransistorThe MAX1818 features a 0.25ΩP-channel MOSFET
pass transistor. Unlike similar designs using PNP pass
transistors, P-channel MOSFETs require no base drive,
which reduces quiescent current. PNP-based regula-
tors also waste considerable current in dropout when
the pass transistor saturates, and use high base-drive
currents under large loads. The MAX1818 does not suf-
fer from these problems and consumes only 125µA of
quiescent current under heavy loads as well as in
dropout.
Output Voltage SelectionThe MAX1818’s Dual Mode operation allows operation
in either a preset voltage mode or an adjustable mode.
Connect SET to GND to select the preset output volt-
age. The two-digit part number suffix identifies the out-
put voltage (see Selector Guide). For example, the
MAX1818EUT33 has a preset 3.3V output voltage.
The output voltage may also be adjusted by connecting
a voltage-divider from OUT to SET to GND (Figure 2).
Select R2 in the 25kΩto 100kΩrange. Calculate R1
with the following equation:
R1 = R2 [(VOUT/ VSET) – 1]
where VSET= 1.25V, and VOUTmay range from 1.25V
to 5.0V.
ShutdownPull SHDNlow to enter shutdown. During shutdown, the
output is disconnected from the input and supply cur-
rent drops to 0.1µA. When in shutdown, POK pulls low
and OUT is high impedance. The capacitance and load
at OUT determine the rate at which VOUTdecays.
SHDNcan be pulled as high as 6V, regardless of the
input and output voltage.
100mV
SHDN
POK
OFF
CIN
1μF
VIN = 2.5V TO 5.5V
OUT VOUT = 1.25V TO 5.0V
COUT
3.3μF
THERMAL
SENSOR
SET
MOSFET
DRIVER WITH
ILIM
SHUTDOWN
LOGIC VREF
1.25V
ERROR
AMPLIFIER
GND
RPOK
100k
LOGIC SUPPLY
VOLTAGE (VOUT)
93% VREF
MAX1818
Figure 1. Functional Diagram
