TLV61220
www.ti.com
SLVSB53 –MAY 2012
For selecting the inductor this would be the suitable value for the current rating. It also needs to be taken into
account that load transients and error conditions may cause higher inductor currents.
Equation 4 helps to estimate whether the device will work in continuous or discontinuous operation depending on
the operating points. As long as the inequation is true, continuous operation is typically established. If the
inequation becomes false, discontinous operation is typically established.
VOUT ´IOUT
> 0.8´100 mA
V
IN
(4)
The following inductor series from different suppliers have been used with TLV61220 converters:
Table 2. List of Inductors
VENDOR
INDUCTOR SERIES
DFE252010C
EPL3015
Toko
Coilcraft
EPL2010
Murata
LQH3NP
Taiyo Yuden
Wurth Elektronik
NR3015
WE-TPC Typ S
Capacitor Selection
Input Capacitor
At least a 10-μF input capacitor is recommended to improve transient behavior of the regulator and EMI behavior
of the total power supply circuit. A ceramic capacitor placed as close as possible to the VBAT and GND pins of
the IC is recommended.
Output Capacitor
For the output capacitor C2 , it is recommended to use small ceramic capacitors placed as close as possible to
the VOUT and GND pins of the IC. If, for any reason, the application requires the use of large capacitors which
can not be placed close to the IC, the use of a small ceramic capacitor with an capacitance value of around
2.2μF in parallel to the large one is recommended. This small capacitor should be placed as close as possible to
the VOUT and GND pins of the IC.
A minimum capacitance value of 4.7 μF should be used, 10 μF are recommended. If the inductor value exceeds
4.7 μH, the value of the output capacitance value needs to be half the inductance value or higher for stability
reasons, see Equation 5.
L
C2 ³
´
2
(5)
The TLV61220 is not sensitive to the ESR in terms of stability. Using low ESR capacitors, such as ceramic
capacitors, is recommended anyway to minimize output voltage ripple. If heavy load changes are expected, the
output capacitor value should be increased to avoid output voltage drops during fast load transients.
Copyright © 2012, Texas Instruments Incorporated
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