Datasheet
LPSMload
II D=
2
1
)(
÷
÷
÷
÷
÷
ø
ö
ç
ç
ç
ç
ç
è
æ
×
-
×=D
SW
IN
OUT
OUTL
fL
V
V
VI
(min)
(max)
(max)
1
TPS62130, TPS62130A
TPS62131, TPS62132, TPS62133
www.ti.com
SLVSAG7B –NOVEMBER 2011–REVISED JUNE 2013
(8)
where
I
L
(max) is the maximum inductor current,
ΔI
L
is the Peak to Peak Inductor Ripple Current,
L(min) is the minimum effective inductor value and
f
SW
is the actual PWM Switching Frequency.
spacing
Calculating the maximum inductor current using the actual operating conditions gives the minimum saturation
current of the inductor needed. A margin of about 20% is recommended to add. A larger inductor value is also
useful to get lower ripple current, but increases the transient response time and size as well. The following
inductors have been used with the TPS6213X and are recommended for use:
Table 2. List of Inductors
Type Inductance [µH] Current [A]
(1)
Dimensions [LxBxH] MANUFACTURER
mm
XFL4020-102ME_ 1.0 µH, ±20% 4.7 4 x 4 x 2.1 Coilcraft
XFL4020-152ME_ 1.5 µH, ±20% 4.2 4 x 4 x 2.1 Coilcraft
XFL4020-222ME_ 2.2 µH, ±20% 3.8 4 x 4 x 2.1 Coilcraft
IHLP1212BZ-11 1.0 µH, ±20% 4.5 3 x 3.6 x 2 Vishay
IHLP1212BZ-11 2.2 µH, ±20% 3.0 3 x 3.6 x 2 Vishay
SRP4020-3R3M 3.3µH, ±20% 3.3 4.8 x 4 x 2 Bourns
VLC5045T-3R3N 3.3µH, ±30% 4.0 5 x 5 x 4.5 TDK
(1) Lower of I
RMS
at 40°C rise or I
SAT
at 30% drop.
spacing
The inductor value also determines the load current at which Power Save Mode is entered:
(9)
Using Equation 8, this current level can be adjusted by changing the inductor value.
Capacitor Selection
Output Capacitor
The recommended value for the output capacitor is 22uF. The architecture of the TPS6213X allows the use of
tiny ceramic output capacitors with low equivalent series resistance (ESR). These capacitors provide low output
voltage ripple and are recommended. To keep its low resistance up to high frequencies and to get narrow
capacitance variation with temperature, it's recommended to use X7R or X5R dielectric. Using a higher value can
have some advantages like smaller voltage ripple and a tighter DC output accuracy in Power Save Mode (see
SLVA463).
Note: In power save mode, the output voltage ripple depends on the output capacitance, its ESR and the peak
inductor current. Using ceramic capacitors provides small ESR and low ripple.
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