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MAX1843ETI+中文资料

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MAX18432.7A, 1MHz, Low-Voltage, Step-Down Regulator with

Internal Synchronous Rectification in TQFN Package

________________________________________________________________Maxim Integrated Products119-1986; Rev 2; 4/06

General Description

The MAX1843 constant-off-time, pulse-width modulated(PWM) step-down DC-DC converter is ideal for use in 5Vand 3.3V to low-voltage conversion necessary in note-book and subnotebook computers. This device featuresan internal PMOS power switch and internal synchronousrectification for high efficiency and reduced componentcount. An external Schottky diode is not required. Theinternal 90mΩpower switch and 70mΩnMOS synchro-nous-rectifier switch easily deliver continuous load cur-rents up to 2.7A. The MAX1843 produces a preset +2.5V,+1.8V, or +1.5V output voltage or an adjustable outputfrom +1.1V to VIN. It achieves efficiencies as high as95%.

The MAX1843 uses 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 setsswitching frequencies up to 1MHz, allowing the user tooptimize performance trade-offs between efficiency, out-put switching noise, component size, and cost. TheMAX1843 features an adjustable soft-start to limit surgecurrents during startup, a 100% duty-cycle mode for lowdropout operation, and a low-power shutdown mode thatdisconnects the input from the output and reduces sup-ply current below 1µA. The MAX1843 is available in a 28-pin TQFN package with an exposed backside pad.

Applications

5V or 3.3V to Low-Voltage Conversion

CPU I/O Ring

Chipset Supplies

Notebook and Subnotebook ComputersFeatures

♦±1% Output Accuracy

♦Up to 1MHz Switching Frequency

♦95% Efficiency

♦Internal pMOS/nMOS Switches

90mΩ/70mΩOn-Resistance at VIN= +4.5V 110mΩ/80mΩOn-Resistance at VIN= +3V

♦Output Voltage

+2.5V, +1.8V, or +1.5V Pin Selectable+1.1V to VINAdjustable

♦+3V to +5.5V Input Voltage Range

♦350µA Operating Supply Current

♦< 1µA Shutdown Supply Current

♦Programmable Constant-Off-Time Operation

♦Idle Mode Operation at Light Loads

♦Thermal Shutdown

♦Adjustable Soft-Start Inrush Current Limiting

♦100% Duty Cycle During Low-Dropout Operation

♦Output Short-Circuit Protection

♦28-Pin TQFN Package

Ordering Information

Idle Mode is a trademark of Maxim Integrated Products, Inc.

MAX

18432526

27

2822

23

24

8910111213

234567LXINSSCOMPINN.C.LXLXPGNDVCCFBSELPGNDPGND

TQFNTOP VIEW

N.C.+11415161718192021

REF

GND

N.C.

N.C.N.C.

FB

TOFFN.C.

LXN.C.

LX

N.C.

SHDN

N.C.Pin Configuration

TOFF

COMPVCC

FBSELSHDNIN

PGND

GND

REFSSLX

FBMAX1843OUTPUT+1.1V TOVININPUT+3V TO +5.5V

0.01µF1µF2.2µF470pF10ΩTypical Configuration

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.PARTTEMPRANGEPIN-PACKAGEPKGCODEMAX1843ETI+-40°C to +85°C28 TQFNT2855-6

+Denotes lead-free package.元器件交易网www.cecb2b.com

MAX18432.7A, 1MHz, Low-Voltage, Step-Down Regulator with

Synchronous Rectification in TQFN Package

2_______________________________________________________________________________________ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VIN= VCC= +3.3V, FBSEL = GND, TA= 0°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functionaloperation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure toabsolute maximum rating conditions for extended periods may affect device reliability.VCC, IN to GND........................................................-0.3V to +6VIN to VCC.............................................................................±0.3VGND to PGND.....................................................................±0.3VAll Other Pins to GND.................................-0.3V to (VCC+ 0.3V)LX Current (Note 1).............................................................±4.7AREF Short Circuit to GND Duration............................ContinuousESD Protection.....................................................................±2kVContinuous Power Dissipation (TA= +70°C)28-Pin TQFN (derate 20mW/°C above +70°C, part mounted on 1in2of 1oz copper)......................................................1.6WOperating Temperature Range...........................-40°C to +85°C Storage Temperature Range.............................-65°C to +150°C Junction Temperature......................................................+150°CLead Temperature (soldering, 10s)................................+300°C

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MAX204EWE中文资料

MAX204EWE中文资料

General DescriptionThe MAX200–MAX211/MAX213 transceivers aredesigned for RS-232 and V.28 communication inter-faces where ±12V supplies are not available. On-boardcharge pumps convert the +5V input to the ±10V need-ed for RS-232 output levels. The MAX201 and MAX209operate from +5V and +12V, and contain a +12V to -12V charge-pump voltage converter.The MAX200–MAX211/MAX213 drivers and receiversmeet all EIA/TIA-232E and CCITT V.28 specifications ata data rate of 20kbps. The drivers maintain the ±5VEIA/TIA-232E output signal levels at data rates inexcess of 120kbps when loaded in accordance with theEIA/TIA-232E specification.The 5µW shutdown mode of the MAX200, MAX205,MAX206, and MAX211 conserves energy in battery-powered systems. The MAX213 has an active-low shut-down and an active-high receiver enable control. Tworeceivers of the MAX213 are active, allowing ring indica-tor (RI) to be monitored easily using only 75µW power.The MAX211 and MAX213 are available in a 28-pinwide small-outline (SO) package and a 28-pin shrinksmall-outline (SSOP) package, which occupies only40% of the area of the SO. The MAX207 is now avail-able in a 24-pin SO package and a 24-pin SSOP. TheMAX203 and MAX205 use no external components,and are recommended for applications with limited circuit board space.ApplicationsComputersLaptops, Palmtops, NotebooksBattery-Powered Equipment

MAX3442EASA+T中文资料

MAX3442EASA+T中文资料

Selector GuideGeneral Description

The MAX3440E–MAX3444E fault-protected RS-485 andJ1708 transceivers feature ±60V protection from signalfaults on communication bus lines. Each device containsone differential line driver with three-state output and onedifferential line receiver with three-state input. The 1/4-unit-load receiver input impedance allows up to 128 trans-ceivers on a single bus. The devices operate from a 5Vsupply at data rates of up to 10Mbps. True fail-safe inputsguarantee a logic-high receiver output when the receiverinputs are open, shorted, or connected to an idle data line.

Hot-swap circuitry eliminates false transitions on thedata bus during circuit initialization or connection to alive backplane. Short-circuit current-limiting and ther-mal shutdown circuitry protect the driver against exces-sive power dissipation, and on-chip ±15kV ESDprotection eliminates costly external protection devices.

MAX4052AESE中文资料

MAX4052AESE中文资料

General Description

The MAX4051/MAX4052/MAX4053 and MAX4051A/

MAX4052A/MAX4053A are low-voltage, CMOS analog

ICs configured as an 8-channel multiplexer (MAX4051/A),

two 4-channel multiplexers (MAX4052/A), and three sin-

gle-pole/double-throw (SPDT) switches (MAX4053/A).

The A-suffix parts are fully characterized for on-resistance

match, on-resistance flatness, and low leakage.

These CMOS devices can operate continuously with

dual power supplies ranging from ±2.7V to ±8V or a

single supply between +2.7V and +16V. Each switch

can handle rail-to-rail analog signals. The off-leakage

current is only 0.1nA at +25°C or 5nA at +85°C

(MAX4051A/MAX4052A/MAX4053A).

All digital inputs have 0.8V to 2.4V logic thresholds,

ensuring TTL/CMOS-logic compatibility when using

±5V or a single +5V supply.

________________________Applications

max3485esa中文资料

max3485esa中文资料

General Description

The MAX3483, MAX3485, MAX3486, MAX3488, MAX3490, and MAX3491 are 3.3V, low-power transceivers for RS-485 and RS-422 communication. Each part contains one driver and one receiver. The MAX3483 and MAX3488 feature slew-rate-limited drivers that minimize EMI and reduce reflections caused by improperly terminated cables, allowing error-free data transmission at data rates up to 250kbps. The partially slew-rate-limited MAX3486 transmits up to 2.5Mbps. The MAX3485, MAX3490, and MAX3491 transmit at up to 10Mbps.

Drivers are short-circuit current-limited and are protected against excessive power dissipation by thermal shutdown circuitry that places the driver outputs into a high-imped-ance state. The receiver input has a fail-safe feature that guarantees a logic-high output if both inputs are open circuit.