AAT1143 查看數據表（PDF） - Skyworks Solutions

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AAT1143

1MHz 400mA Step-Down Converter

Skyworks Solutions 

DATA SHEET

AAT1143

1MHz 400mA Step-Down Converter

Figure 2: AAT1143 Evaluation Board

Top Side.

Figure 3: Exploded View of Evaluation

Board Top Side Layout.

Figure 4: AAT1143 Evaluation Board

Bottom Side.

Adjustable Output Resistor Selection

For applications requiring an adjustable output voltage,

the 0.6V version can be externally programmed. Resistors

R1 and R2 of Figure 5 program the output to regulate at

a voltage higher than 0.6V. To limit the bias current

required for the external feedback resistor string while

maintaining good noise immunity, the minimum sug-

gested value for R2 is 59k. Although a larger value will

further reduce quiescent current, it will also increase the

impedance of the feedback node, making it more sensi-

tive to external noise and interference. Table 2 summa-

rizes the resistor values for various output voltages with

R2 set to either 59k for good noise immunity or 221k

for reduced no load input current.

R1

=

⎛ VOUT

⎝ VREF

-1⎞⎠

·

R2

=

⎛ 1.5V

⎝ 0.6V

-

1 ⎞⎠

·

59kΩ

=

88.5kΩ

The adjustable version of the AAT1143, combined with

an external feedforward capacitor (C4 in Figure 1),

delivers enhanced transient response for extreme pulsed

load applications. The addition of the feedforward

capacitor typically requires a larger output capacitor C1

for stability.

Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com

12

201983B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • March 25, 2013

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