DIL + VO

1 *

V

O

V

I

L

f

I

L

(max) + IO(max) )

DIL

2

f = Switching frequency (850 kHz typical)

L = Inductor value

∆IL = Peak-to-peak inductor ripple current

V

O +

V

FB

R1 ) R2

R2

R1 + R2

V

O

V

FB

–R2

V

FB +

0.5V

TPS62050, TPS62051, TPS62052, TPS62054, TPS62056

www.ti.com

SLVS432F – SEPTEMBER 2002 – REVISED JUNE 2015

Typical Applications (continued)

Table 1. Bill of Materials for Adjustable Version (continued)

REFERENCE

PART NUMBER

VALUE

MANUFACTURER

generic metal film resistor;

R6

100 k

Ω

—

tolerance 1%

C(ff)

generic ceramic capacitor; COG

6.8 pF

—

10.2.1.2 Detailed Design Procedure

All graphs have been generated using the circuit as shown unless otherwise noted. For output voltages other

removed and the feedback pin is directly connected to the output.

(2)

Table 2. Values for Resistor Combinations and Feedback Capacitors

NOMINAL OUTPUT VOLTAGE

EQUATION

POSSIBLE RESISTOR COMBINATION TYPICAL FEEDBACK CAPACITOR

0.7 V

R1 = 0.4 × R2

R1 = 270 k, R2 = 680 k

1.2 V

R1 = 1.4 × R2

R1 = 510 k, R2 = 360 k (1.21 V)

1.5 V

R1 = 2 × R2

R1 = 300 k, R2 = 150 k (1.5 V)

1.8 V

R1 = 2.6 × R2

R1 = 390 k, R2 = 150 k (1.80 V)

2.5 V

R1 = 4 × R2

R1 = 680 k, R2 = 169 k (2.51 V)

3.3 V

R1 = 5.6 × R2

R1 = 560 k, R2 = 100 k (3.3 V)

5 V

R1 = 9 × R2

R1 = 820 k, R2 = 91 k (5 V)

10.2.1.2.1

Inductor Selection

A 10-µH minimum inductor must be used with the TPS6205x family of devices. Values larger than 22 µH or

smaller than 10 µH may cause stability problems due to the internal compensation of the regulator. After

choosing the inductor value of typically 10 µH, two additional inductor parameters must be considered: the

current rating of the inductor and the DC resistance. The DC resistance of the inductance directly influences the

efficiency of the converter. Therefore, an inductor with lowest DC resistance must be selected for highest

efficiency. To avoid saturation of the inductor, the inductor must be rated at least for the maximum output current

plus half the inductor ripple current which is calculated using Equation 3.

(3)

The highest inductor current occurs at maximum VIN . A more conservative approach is to select the inductor

current rating just for the maximum switch current of the TPS6205x device, which is 1.4 A maximum. See

Table 3 for inductors that have been tested for operation with the TPS6205x devices.

Table 3. Inductors

MANUFACTURER

TYPE

INDUCTANCE

DC RESISTANCE

SATURATION CURRENT

SLF7032T-

10 µH ±20%

53 m

Ω ±20%

1.4 A

100M1R4SLF7032T-

22 µH ±20%

110 m

Ω ±20%

0.96 A

TDK

220M96SLF7045T-

10 µH ±20%

36 m

Ω ±20%

1.3 A

100M1R3SLF7045T-

22 µH ±20%

61 m

Ω ±20%

0.9 A

100MR90

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