÷

ø

ö

ç

è

æ

+

´

=

÷

ø

ö

ç

è

æ

+

´

=

2

1

1

6

.

0

2

1

1

R

R

V

R

R

V

V

FB

OUT

9

TLV62569, TLV62569P

www.ti.com

SLVSDG1C – DECEMBER 2016 – REVISED OCTOBER 2017

Product Folder Links: TLV62569 TLV62569P

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Copyright © 2016–2017, Texas Instruments Incorporated

(1)

Inductor tolerance and current de-rating is anticipated. The effective inductance can vary by +20% and -30%.

(2)

Capacitance tolerance and bias voltage de-rating is anticipated. The effective capacitance can vary by +20% and -50%.

(3)

This LC combination is the standard value and recommended for most applications.

2. Optimize the design for key parameters such as efficiency, footprint, and cost using the optimizer dial.

3. Compare the generated design with other possible solutions from Texas Instruments.

The WEBENCH Power Designer provides a customized schematic along with a list of materials with real-time

pricing and component availability.

In most cases, these actions are available:

•

Run electrical simulations to see important waveforms and circuit performance

•

Run thermal simulations to understand board thermal performance

•

Export customized schematic and layout into popular CAD formats

•

Print PDF reports for the design, and share the design with colleagues

Get more information about WEBENCH tools at www.ti.com/WEBENCH.

8.2.2.2 Setting the Output Voltage

An external resistor divider is used to set output voltage according to Equation 2.

When sizing R2, in order to achieve low current consumption and acceptable noise sensitivity, use a maximum of

200 kΩ for R2. Larger currents through R2 improve noise sensitivity and output voltage accuracy but increase

current consumption.

(2)

A feed forward capacitor, C3 improves the loop bandwidth to make a fast transient response (shown in

Figure 19). 6.8-pF capacitance is recommended for R2 of 100-kΩ resistance. A more detailed discussion on the

optimization for stability vs. transient response can be found in SLVA289.

8.2.2.3 Output Filter Design

The inductor and output capacitor together provide a low-pass filter. To simplify this process, Table 4 outlines

possible inductor and capacitor value combinations. Checked cells represent combinations that are proven for

stability by simulation and lab test. Further combinations should be checked for each individual application.

Table 4. Matrix of Output Capacitor and Inductor Combinations

(2)

4.7

10

22

2 x 22

100

0.6

1

+

2.2

1.2

1

+

+

2.2

+

1.8

1

+

+

+

2.2

+

+