OUT

REF

R1

V

= V

x 1 +

R2

æ

ö÷

ç

÷

ç

÷÷

çè

ø

VIN

GND

EN

FB

SW

TPS62590DRV

L

V

MODE

2.2 H

m

C

OUT

10mF

C1

22pF

R1

R2

C

IN

10mF

PwrPAD

Up to 1A

V

2.5 V to 5.5 V

IN

OUT

5

4

2

1

3

6

360k

180k

=1.8V

TPS62590

www.ti.com

SLVS897C – JANUARY 2009 – REVISED DECEMBER 2015

8 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component

specification, and TI does not warrant its accuracy or completeness. TI’s customers are

responsible for determining suitability of components for their purposes. Customers should

validate and test their design implementation to confirm system functionality.

8.1 Application Information

The TPS62590 device is a high-efficiency synchronous step-down DC–DC converter featuring power-save mode

or 2.25-MHz fixed frequency operation.

8.2 Typical Application

Figure 6. TPS62590DRV Adjustable 1.8 V

8.2.1 Design Requirements

The device operates over an input voltage range from 2.5 V to 5.5 V. The output voltage is adjustable using an

external feedback divider.

8.2.2 Detailed Design Procedure

8.2.2.1 Output Voltage Setting

(2)

To minimize the current through the feedback divider network, R2 should be 180 k

Ω or 360 kΩ. The sum of R1

and R2 should not exceed ~1 M

Ω, to keep the network robust against noise. An external feed forward capacitor

C1 is required for optimum load transient response. The value of C1 should be in the range between 22 pF and

33 pF.

Route the FB line away from noise sources, such as the inductor or the SW line.

8.2.2.2 Output Filter Design (Inductor and Output Capacitor)

The TPS62590 is designed to operate with inductors in the range of 1.5

μH to 4.7 μH and with output capacitors

in the range of 4.7

μF to 22 μF. The part is optimized for operation with a 2.2-μH inductor and 10-μF output

capacitor. Larger or smaller inductor values can be used to optimize the performance of the device for specific

operation conditions. For stable operation, the L and C values of the output filter may not fall below 1-

μH

effective inductance and 3.5-

μF effective capacitance.

8.2.2.2.1

Inductor Selection

The inductor value has a direct effect on the ripple current. The selected inductor has to be rated for its DC

resistance and saturation current. The inductor ripple current (

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