MAX1760HEUB+T中文资料(10)

0.8A, Low-Noise, 1MHz,Step-Up DC-DC Converter

age, and output capacitors with working voltage ratingshigher than the output.

The input filter capacitor reduces peak currents drawnfrom the input source and also reduces input switchingnoise. The input voltage source impedance determinesthe required value of the input capacitor. When operat-ing directly from one or two NiMH cells placed close tothe MAX1760, use a single 33µF low-ESR input filtercapacitor. With higher impedance batteries, such asalkaline and Li+, a higher value input capacitor mayimprove efficiency.

The output filter capacitor reduces output ripple voltageand provides the load with transient peak currentswhen necessary. For the output, a 100µF, low-equiva-lent-series-resistance (ESR) capacitor is recommendedfor most applications.

Sanyo POSCAP, Panasonic SP/CB, and Kemet T510are good low-ESR capacitors. Low-ESR tantalumcapacitors offer a good tradeoff between price andperformance. Do not exceed the ripple current ratingsOther External Components

Two ceramic bypass capacitors are required for properoperation. Bypass REF to GND with 0.22µF. Also,bypass OUT to GND with a 0.68µF ceramic capacitor,and connect OUT to POUT with a 4.7 resistor. Each ofthese components should be placed as close to itsrespective IC pins as possible, within 0.2in (5mm).Table 4 lists suggested suppliers.

MAX1760/MAX1760H

Layout Considerations

High switching frequencies and large peak currentsmake PCB layout a critical part of design. Poor designcauses excessive EMI and ground bounce, both ofwhich can cause instability or regulation errors by cor-rupting the voltage and current feedback signals.

Power components—such as the inductor, converter IC,filter capacitors, and output diode—should be placedas close together as possible, and their traces shouldbe kept short, direct, and wide. Keep the voltage feed-back network very close to the IC, within 0.2in (5mm) ofthe FB pin. Keep noisy traces, such as those from theof tantalum capacitors. Avoid aluminum electrolyticcapacitors; their high ESR typically results in higherLX pin, away from the voltage feedback network andoutput ripple voltage.

guarded from them using grounded copper. Refer to theMAX1760 evaluation kit for a full PCB example.

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0.8A, Low-Noise, 1MHz, Step-Up DC-DC Converter

0H

Package Information

(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,go to 671XAM/0671XAM12______________________________________________________________________________________