MAX1806资料

19-2018; Rev 0; 4/01

500mA, Low-Voltage Linear Regulator in µMAX

General Description

FeaturesThe MAX1806 low-dropout linear regulator operatesfrom a +2.25V to +5.5V supply and delivers a guaran-oGuaranteed 500mA Output Currentteed 500mA load current with low 175mV dropout. TheoOutput Down to 0.8V

high-accuracy (±1%) output voltage is preset at aninternally trimmed voltage (see Selector Guide) or canoLow 175mV Dropout at 500mA

be adjusted from +0.8V to +4.5V with an external resis-o±1% Output Voltage Accuracy

tive-divider.

Preset at 0.8V, 1.5V, 1.8V, 2.5V, or 3.3VAn internal PMOS pass transistor allows low 210µAAdjustable from 0.8V to 4.5Vsupply current, making this device ideal for portableequipment such as personal digital assistants (PDAs),oPower-OK Output

cellular phones, cordless phones, and other equip-oLow 210µA Ground Current ment, including base stations and docking stations.o0.02µA Shutdown CurrentOther features include an active-low, power-OK outputthat indicates when the output is out of regulation, aoThermal Overload Protection0.02µA shutdown mode, short-circuit protection, andthermal shutdown protection. The MAX1806 comes in aoOutput Current Limit

miniature 1.3W, 8-pin power-µMAX package with aoTiny 1.3W, 8-Pin Power-µMAX Package

metal pad on the underside of the package.

Ordering InformationApplications

PARTT EM P. R AN GE PIN-PACKAGEMAX1806EUA_ _-40°C to +85°C8 Power-µMAXNotebook Computers

Cellular and Cordless TelephonesSelector GuidePDAs

Palmtop ComputersPART AND SUFFIXVOUT (V)TOP MARKBase StationsMAX1806EUA333.3AAAGMAX1806EUA252.5AAAHUSB HubsMAX1806EUA181.8AAAIDocking Stations

MAX1806EUA151.5AAAJMAX1806EUA080.8AAAKTypical Operating Circuit

Pin Configuration

VINVOUT+2.25V TO +5.5V0.8V TO 4.5VTOP VIEWINNCOUTCINC1µFOUT10µFIN18OUTMAX1806RPOK100kΩIN27OUTONMAX1806SHDNPOKTO POK36SETOFFµCSHDN45GNDSETGNDµMAX________________________________________________________________Maxim Integrated Products1

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.

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500mA, Low-Voltage Linear Regulator in µMAXMAX1806ABSOLUTE MAXIMUM RATINGS

IN, SHDN, POK, SET to GND...................................-0.3V to +6VOUT to GND................................................-0.3V to (VIN+ 0.3V)Output Short-Circuit Duration.....................................ContinuousContinuous Power Dissipation (TA= +70°C)

8-Pin Power-µMAX (derate 17mW/°C above +70°C).......1.3W

Operating Temperature.......................................-40°C to +85°CJunction Temperature......................................................+150°CStorage Temperature Range.............................-65°C to +150°CLead Temperature (soldering, 10s).................................+300°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.

ELECTRICAL CHARACTERISTICS

(VIN= VOUT(SETPOINT)+ 500mV or VIN= +2.25V whichever is greater, SET = GND, SHDN= IN, TA= 0°C to +85°C, unless otherwisenoted. Typical values are at TA= +25°C.)

PARAMETERInput VoltageInput Undervoltage LockoutOutput Voltage Accuracy(Preset Mode)Adjustable Output VoltageTA = +85°C, IOUT = 100mASET Voltage Threshold(Adjustable Mode)Maximum Output CurrentShort-Circuit Current LimitSET Dual Mode™ ThresholdSET Input Bias CurrentGround-Pin CurrentISETIQVSET = +0.8VIOUT = 1mAIOUT = 500mAVOUT = +2.25VDropout Voltage (Note 1)Line RegulationLoad RegulationOutput Voltage NoiseSHUTDOWNShutdown Supply CurrentSHDN Input ThresholdSHDN Input Bias CurrentStartup TimeSYMBOLVINVUVLOCONDITIONSRising, 40mV hysteresisTA = +85°C, IOUT = 100mATA = +85°C, IOUT = 1mA to 500mATA = 0°C to +85°C, IOUT = 1mA to 500mA,VIN > VOUT + 0.5VMIN2.251.85-1-1.5-30.8790786774500TYP2.0MAX5.52.15+1+1.5+34.5810814UNITSVVVOUT%VVSETTA = +85°C, IOUT = 1mA to 500mATA = 0°C to +85°C, IOUT = 1mA to 500mA,VIN > VOUT + 0.5VVOUT = 0VmV800826m ARM SIOUTILIM70035-100140080210575259201147015.53000.022300125+1004003843152550.12535mAmVnAµAIOUT = 500mA∆VLNR∆VLDRVOUT = +2.8VVOUT = +4.0VmV%/Vp pm /m AµVRMSV om ( VO U + 100m V ) to 5.5V , IL 5m AI N fr T OA D = IOUT = 1mA to 500mA10Hz to 1MHz, COUT = 10µF (ESR < 0.1Ω)IOFFVIHVILISHDNTSTARTSHDN = GND, VIN = 5.5V1.650.6µAVnAµsSHDN = GND or INC 10µF, ti me fr om SHDN hig h to P OK hig hOUT = 1040100Dual Mode is a trademark of Maxim Integrated Products, Inc.2

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500mA, Low-Voltage Linear Regulator in µMAX

ELECTRICAL CHARACTERISTICS (continued)

(Vnoted. Typical values are at TIN= VOUT(SETPOINT)+ 500mV or VIN= +2.25V whichever is greater, SET = GND, SHDN= IN, TA= 0°C to +85°C, unless otherwiseA= +25°C.)PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSPOWER-OKPOK Output Low VoltageVOLSinking 2mA550mVOperating Voltage Range forValid POK OutputSinking 100µA1.05.5VOutput High-Leakage CurrentVPOK = +5.5V100nAThresholdRising edge, referred to VOUT(NOMINAL)909396%THERMAL PROTECTIONTher ma l S hutd own Tem pe ratureTSHDN170°CThermal Shutdown Hysteresis∆TSHDN20°CELECTRICAL CHARACTERISTICS

(VIN= VOUT(SETPOINT)+ 500mV or VIN= +2.25V whichever is greater, SET = GND, SHDN= IN, TA= -40°C to +85°C, unless other-wise noted. Typical values are at TA= +25°C.) (Note 2)

PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSInput VoltageVIN2.255.5VInput Undervoltage LockoutVUVLORising, 40mV hysteresis1.852.15VOutput Voltage Accuracy(Preset Mode)VOUTIOUT = 1mA to 500mA-4+4%Adjustable Output Voltage0.84.5VSET Voltage Threshold(Adjustable Mode)VSETIOUT = 1mA to 500mA766834mVMaximum Output CurrentIOUT500m ARM SShort-Circuit Current LimitILIMVOUT = 0V7002500mASET Dual Mode™ Threshold35125mVSET Input Bias CurrentISETVSET = +0.8V-100+100nAGround-Pin CurrentIQIOUT = 1mA400µAVOUT = +2.25V259384Dropout Voltage (Note 1)IOUT = 500mAVOUT = +2.8V201315mVVOUT = +4.0V147255Line Regulation∆VLNRV I N fr om ( VO U T + 100m V ) to 5.5V , IL OA D = 5m A-0.175+0.175%/VLoad Regulation∆VLDRIOUT = 1mA to 500mA35p pm /m ASHUTDOWNShutdown Supply CurrentIOFFSHDN = GND, VIN = 5.5V5µASHDN Input ThresholdVIH2.5V < VIN < 5.5V1.6V2.5V < VVILIN < 5.5V0.6SHDN Input Bias CurrentISHDNSHDN = GND or IN100nA_______________________________________________________________________________________3

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500mA, Low-Voltage Linear Regulator in µMAXMAX1806ELECTRICAL CHARACTERISTICS (continued)

(VIN= VOUT(SETPOINT)+ 500mV or VIN= +2.25V whichever is greater, SET = GND, SHDN= IN, TA= -40°C to +85°C, unless other-wise noted. Typical values are at TA= +25°C.) (Note 2)

PARAMETERPOWER-OKPOK Output Low VoltageOperating Voltage Range forValid POK OutputOutput High-Leakage CurrentThresholdVOLSinking 2mASinking 100µAVPOK = +5.5VRising edge, referred to VOUT(NOMINAL)891.0505.510097mVVnA%SYMBOLCONDITIONSMINTYPMAXUNITSNote 1:Dropout voltage is defined as VIN- VOUT, when VOUTis 100mV below the value of VOUTand when VIN= VOUT(NOM)+0.5V.For 2.25V ≤VOUT≤4.0V, dropout voltage limits are linearly interpolated from the values listed. For VOUT< 4.0V, dropout voltage limit is equal to the value for VOUT= 4.0V.

Note 2:Specifications to -40°C are guaranteed by design, not production tested.

Typical Operating Characteristics(MAX1806EUA33, VIN= VOUT+ 500mV, SHDN= IN, CIN= 1µF, COUT= 10µF, TA= +25°C, unless otherwise noted.)

OUTPUT VOLTAGE vs. INPUT VOLTAGE

MAX1806 toc01OUTPUT VOLTAGE vs. LOAD CURRENT

MAX1806 toc02OUTPUT VOLTAGE vs. TEMPERATURE

VIN = VOUT + 500mVIOUT = 0MAX1806 toc033.5

IOUT = 0mA3.0OUTPUT VOLTAGE (V)2.52.01.51.00.50

IOUT = 500mA3.323.31OUTPUT VOLTAGE (V)3.303.293.283.273.263.25

3.343.33OUTPUT VOLTAGE (V)3.323.313.303.293.28

1.52.02.53.03.54.04.55.05.56.0

INPUT VOLTAGE (V)

0100200300400500600700800

LOAD CURRENT (mA)

-40-1510356085

TEMPERATURE (°C)

DROPOUT VOLTAGE vs. LOAD CURRENT

350DROPOUT VOLTAGE (mV)3002502001501005000

100200300400500600700800

LOAD CURRENT (mA)

TA = -40°CTA = +25°CTA = +85°CMAX1806 toc04DROPOUT VOLTAGE vs.OUTPUT VOLTAGE

0.28DROPOUT VOLTAGE (V)0.260.240.220.200.180.160.14

2.0

2.5

3.0

3.5

4.0

4.5

OUTPUT VOLTAGE (V)

6005505004504003503002502001501005002.0

MAX1806 toc05GROUND-PIN CURRENT vs.

INPUT VOLTAGE

MAX1806 toc06400

GROUND-PIN CURRENT (µA)IOUT = 500mAIOUT = 0mA2.53.03.54.04.55.05.56.0

INPUT VOLTAGE (V)

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500mA, Low-Voltage Linear Regulator in µMAX

Typical Operating Characteristics (continued)

(MAX1806EUA33, VIN= VOUT+ 500mV, SHDN= IN, CIN= 1µF, COUT= 10µF, TA= +25°C, unless otherwise noted.)

GROUND-PIN CURRENT vs.

LOAD CURRENT

MAX1806 toc07MAX1806450µA)400VIN = 5.5VVIN = VOUT + 500mVIOUT = 0MAX1806 toc08(µA)190

-50MAX1806 toc09500

GROUND-PIN CURRENT vs.

TEMPERATURE

200

-60

POWER-SUPPLY REJECTION RATIO

vs. FREQUENCY

( TTNNEE-40R350RRVIN = 3.8VR180

)BUUd(CC RN300NR-30IIPPS--D170

PDN250NUUO-20

RG200ORG160

150-10COUT = 10µF100

150

0

IOUT = 50mA0

100200300400500600700800

-40

-15

10

35

60

85

0.01

0.1

1

10

100

1000

LOAD CURRENT (A)

TEMPERATURE (°C)

FREQUENCY (kHz)

OUTPUT SPECTRAL NOISE DENSITY

vs. FREQUENCY

OUTPUT NOISE DC TO 1MHz

10

MAX1806 toc1101)czCotHOUT = 10µF √I6OUT = 50mA081/VXAµM( YTI1

SNED ESIVOUT ON 0.1

1mV/div

LARTCEPS TU0.01PTUVOUT = 3.3VOR0.001

OUT = 66Ω (50mA)0.1

1

10100

1000

20ms/div

FREQUENCY (kHz)

REGION OF STABLE COUT ESR

vs. LOAD CURRENT

LOAD-TRANSIENT RESPONSE

100

MAX1806 toc1321cot 6081XAMIOUT

R10

S200mA/div

E CTOUT = 10µFUOC FO1

NVOUT OIG20mV/div

ERSTABLE REGION0.1

VIN = VOUT + 500mVCIN = 10µF0.01

ROUT = 660Ω TO 6.6Ω (5mA TO 500mA)0

100200300400500600700800

10µs/div

FREQUENCY (kHz)

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500mA, Low-Voltage Linear Regulator in µMAXMAX1806Typical Operating Characteristics (continued)

(MAX1806EUA33, VIN= VOUT+ 500mV, SHDN= IN, CIN= 1µF, COUT= 10µF, TA= +25°C, unless otherwise noted.)

LOAD-TRANSIENT RESPONSE

NEAR DROPOUT

LINE-TRANSIENT RESPONSE

MAX1806 toc15MAX1806 toc146VVIN 1V/div3V

IOUT

200mA/div

VIN = VOUT + 100mVCIN = 10µFROUT = 660Ω TO 6.6Ω (5mA TO 500mA)10µs/div

VOUT 50mV/div

VOUT 10mV/div

200µs/div

SHUTDOWN WAVEFORM

MAX1806 toc16POK WAVEFORM

MAX1806 toc172VVSHDN1V/div03VVOUT 1V/div0

ROUT = 6.6Ω (500mA)20µs/div

ROUT = 66Ω (50mA)200µs/div

5VVIN2V/div0VOUT2V/div0VPOK 2V/div0

Pin DescriptionPIN1, 234567, 8NAMEINPOKSHDNGNDSETOUTFUNCTIONRegulator Input. Supply voltage can range from +2.25V to +5.5V. Bypass with a 1µF capacitor to GND (seeCapacitor Selection and Regulation Stability). Connect both input pins together externally.Open-Drain, Active-Low Power-OK Output. POK remains low while the output voltage (VOUT) is below thePOK threshold. Connect a 100kΩ pullup resistor from POK to OUT.Active-Low Shutdown Input. A logic low at SHDN reduces supply current to 0.02µA. In shutdown, the POKoutput is low. Connect SHDN to IN for normal operation.Ground. This pin and the exposed pad also function as a heatsink. Solder both to a large pad or to thecircuit-board ground plane to maximize power dissipation.Voltage-Setting Input. Connect SET to GND for preset output. Connect an external resistive voltage-dividerfrom OUT to SET to set the output voltage between 0.8V and 4.5V. The SET regulation voltage is 800mV.Regulator Output. OUT sources up to 500mA. Bypass OUT with a 10µF low-ESR capacitor to GND.Connect both OUT pins together externally.6_______________________________________________________________________________________

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500mA, Low-Voltage Linear Regulator in µMAX

Detailed Description

The MAX1806 is a low-dropout, low-quiescent-currentlinear regulator. The device supplies loads up to500mA and is available with preset output voltages. Asillustrated in Figure 1, the MAX1806 includes a 0.8V ref-erence, error amplifier, P-channel pass transistor, andinternal feedback voltage-divider.

The reference is connected to the error amplifier, whichcompares it with the feedback voltage and amplifiescurrent drops to 0.02µA. When in shutdown, POK pullslow. The capacitance and load at OUT determine therate at which VOUTdecays. SHDNcan be pulled ashigh as +6V, regardless of the input and output voltage.

MAX1806Power-OK Output

The POK output pulls low when OUT is less than 93% ofthe nominal regulation voltage. Once OUT exceeds93% of the nominal voltage, POK goes high imped-ance. POK is an open-drain N-channel output. Tothe difference. If the feedback voltage is lower than theobtain a logic voltage output, connect a pullup resistorreference voltage, the pass-transistor gate is pulledfrom POK to OUT. A 100kΩresistor works well for mostlower, which allows more current to pass to the outputapplications. POK can be used to signal a microcon-increasing the output voltage. If the feedback voltage istroller (µC), or drive an external LED to indicate powertoo high, the pass-transistor gate is pulled up, allowingfailure. When the MAX1806 is shutdown, POK is heldless current to pass to the output.

low independent of the output voltage. If unused, leaveThe output voltage is fed back through either an inter-POK grounded or unconnected.

nal resistive voltage-divider connected to OUT or anexternal resistor network connected to SET. The dual-Current Limit

mode comparator examines VThe MAX1806 monitors and controls the pass transis-is below 35mV, the internal feedbackSETand selects the feed-back path. If Vtor’s gate voltage, limiting the output current to 1.4Apath is used, and the output is regulated to the factory-SET(typ). The output can be shorted to ground for an indefi-preset voltage. Additional blocks include an output cur-nite period of time without damaging the part.

rent limiter, thermal sensor, and shutdown logic.

Thermal Overload Protection

Internal P-Channel Pass Transistor

Thermal overload protection limits total power dissipa-The MAX1806 features a 0.4ΩP-channel MOSFET passtion in the MAX1806. When the junction temperaturetransistor. Unlike similar designs using PNP pass tran-exceeds Tsistors, P-channel MOSFETs require no base drive,pass transistor, allowing the device to cool. The thermalJ= +170°C, a thermal sensor turns off thewhich reduces operating current. PNP-based regula-sensor turns the pass transistor on again after the junc-tors also waste considerable current in dropout whention temperature cools by 20°C, resulting in a pulsedthe pass transistor saturates, and use high base-driveoutput during continuous thermal overload conditions.currents under large loads. The MAX1806 does not suf-Thermal overload protection protects the MAX1806 infer from these problems.

the event of fault conditions. For continuous operation,do not exceed the absolute maximum junction-temper-Output Voltage Selection

ature rating of TJ= +150°C.

The MAX1806’s dual-mode operation allows operationin either a preset voltage mode or an adjustable mode.Operating Region and Power Dissipation

Connect SET to GND to select the preset output volt-The MAX1806’s maximum power dissipation dependsage. The two-digit part number suffix identifies the out-on the thermal resistance of the IC package and circuitput voltage (see Selector Guide). For example, theboard, the temperature difference between the dieMAX1806EUA33 has a preset 3.3V output voltage. Thejunction and ambient air, and the rate of air flow. Theoutput voltage may also be adjusted by connecting apower dissipated in the device is P = IOUT✕(VIN-voltage-divider from OUT to SET (Figure 2). Select R2 inVOUT). The maximum allowed power dissipation isthe 25kΩto 100kΩrange. Calculate R1 with the follow-1.3W or:

ing equation:

PMAX = (TJ(MAX)- TA) / (θJC+ θCA)

R1 = R2 [(VOUT/ VSET) - 1]where Twhere VMAX1806 die junction and the surrounding air, J- TAis the temperature difference between theθSET= 0.8V, and VOUTmay range from 0.8VJC isto 4.5V.

the thermal resistance from the junction to the case,and θShutdown

through the PC board, copper traces, and other materi-CAis the thermal resistance from the caseDrive SHDNlow to enter shutdown. During shutdown,als to the surrounding air. The MAX1806 package fea-the output is disconnected from the input, and supply

tures an exposed thermal pad on its underside. Thispad lowers the package’s thermal resistance by provid-_______________________________________________________________________________________

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500mA, Low-Voltage Linear Regulator in µMAXMAX1806 VIN+2.25V TO +5.5VCIN1µFININTHERMALSENSORMOSFETDRIVER WITHILIMOUTPRESET MODEVOUT0.8V TO 3.3VCOUT 10µFONOFFSHDNOUTSHUTDOWNLOGICERRORAMPLIFIER VREF0.8VLOGIC SUPPLYVOLTAGE (VOUT)RPOK100kΩTOµCPOKMAX1806SET93% VREF80mVGNDFigure 1. Functional Diagram

ing a direct heat conduction path from the die to the PCboard. Connect the exposed backside pad and GND tothe system ground using a large pad or ground plane,or multiple vias to the ground plane layer.

The MAX1806 delivers up to 0.5A(RMS) and operateswith input voltages up to 5.5V, but not simultaneously.High output currents can only be sustained when input-output differential is within the limits outlined.

output capacitors. The output capacitor’s (COUT) ESRaffects stability and output noise. Use output capacitorswith an ESR of 0.1Ωor less to ensure stability and opti-mum transient response. Surface-mount ceramiccapacitors have very low ESR and are commonly avail-able in values up to 10µF. Connect CINand COUTasclose to the MAX1806 as possible.

Noise, PSRR, and Transient Response

The MAX1806 is designed to operate with low dropoutvoltages and low quiescent currents, while still main-taining good noise, transient response, and AC rejec-tion. See the Typical Operating Characteristicsfor aplot of Power-Supply Rejection Ratio (PSRR) vs. Freq-uency. When operating from noisy sources, improvedsupply-noise rejection and transient response can beachieved by increasing the values of the input and output bypass capacitors and through passive-filtering techniques. The MAX1806 load-transient

Applications Information

Capacitor Selection and Regulator

Stability

Connect a 1µF capacitor between IN and ground and a10µF low equivalent series resistance (ESR) capacitorbetween OUT and ground. The input capacitor (CIN)lowers the source impedance of the input supply.Reduce noise and improve load-transient response,stability, and power-supply rejection by using larger

8

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500mA, Low-Voltage Linear Regulator in µMAX

0.8R1 = R2VOUT- 1CONTINUOUS CURRENT LIMIT0.7)INOUT0.8VA( TN0.6+2.25V TO +5.5V VINVEOUTRTA = +50°CINOUTRUC0.5 TUPT0.4TCINUA = +85°CO1µFMAX1806COUT10µFR1 M0.3TA = +70°CUMTYPICAL VIDROPOUT LIMITXONA0.2MSHDNSET0.1POWER-µMAX PACKAGE OPERATINGOFFREGION AT TJ(MAX) = +150°C000.51.01.52.02.53.03.54.04.55.0R2INPUT-OUTPUT VOLTAGE DIFFERENTIAL (V)POKGNDFigure 3. Power Operating Regions: Maximum Output Currentvs. Supply Voltage

Figure 2. Adjustable Output Using External Feedback Resistors

response graphs (see Typical Operating Characteris-tics) show two components of the output response: aDC shift from the output impedance due to the loadcurrent change, and the transient response. A typicaltransient overshoot for a step change in the load cur-rent from 5mA to 500mA is 40mV. Increasing the outputcapacitor’s value and decreasing the ESR attenuatesthe overshoot.

Input-Output (Dropout) Voltage

A regulator’s minimum input-to-output voltage differen-tial (dropout voltage) determines the lowest usable sup-ply voltage. In battery-powered systems, thisdetermines the useful end-of-life battery voltage.Because the MAX1806 uses a P-channel MOSFET passtransistor, its dropout voltage is a function of drain-to-source on-resistance (Rcurrent (see Typical Operating CharacteristicsDS(ON)) multiplied by the load):

VDROPOUT= VIN- VOUT= RDS(ON)✕IOUT

Chip Information

TRANSISTOR COUNT: 949

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500mA, Low-Voltage Linear Regulator in µMAXMAX1806Package Information

8L, µMAX, EXP PAD.EPSNote:The MAX1806 has on exposed thermal pad on the bottom side of the package.Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses areimplied. Maxim reserves the right to change the circuitry and specifications without notice at any time.

10____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600©2001 Maxim Integrated Products

Printed USA

is a registered trademark of Maxim Integrated Products.