TPS84610 Datasheet, PDF (11/27 Pages) Texas Instruments – 2.95-V to 6-V Input, 6-A Synchronous Buck, Integrated Power Solution

TPS84610
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CAPACITOR RECOMMENDATIONS FOR THE TPS84610 POWER SUPPLY
SLVSAZ4 – OCTOBER 2011
Capacitor Technologies
Electrolytic, Polymer-Electrolytic Capacitors
When using electrolytic capacitors, high-quality, computer-grade electrolytic capacitors are recommended.
Polymer-electrolytic type capacitors are recommended for applications where the ambient operating temperature
is less than 0°C. The Sanyo OS-CON capacitor series is suggested due to the lower ESR, higher rated surge,
power dissipation, ripple current capability, and small package size. Aluminum electrolytic capacitors provide
adequate decoupling over the frequency range of 2 kHz to 150 kHz, and are suitable when ambient temperatures
are above 0°C.
Ceramic Capacitors
The performance of aluminum electrolytic capacitors is less effective than ceramic capacitors above 150 kHz.
Multilayer ceramic capacitors have a low ESR and a resonant frequency higher than the bandwidth of the
regulator. They can be used to reduce the reflected ripple current at the input as well as improve the transient
response of the output.
Tantalum, Polymer-Tantalum Capacitors
Polymer-tantalum type capacitors are recommended for applications where the ambient operating temperature is
less than 0°C. The Sanyo POSCAP series and Kemet T530 capacitor series are recommended rather than many
other tantalum types due to their lower ESR, higher rated surge, power dissipation, ripple current capability, and
small package size. Tantalum capacitors that have no stated ESR or surge current rating are not recommended
for power applications.
Input Capacitor
The TPS84610 requires a minimum input capacitance of 47 μF of ceramic capacitance. An additional 220 μF
polymer-tantalum capacitor is recommended for applications with transient load requirements. The combined
ripple current rating of the input capacitors must be at least 3000 mArms. Table 4 includes a preferred list of
capacitors by vendor. For applications where the ambient operating temperature is less than 0°C, an additional
1 μF, X5R or X7R ceramic capacitor placed between VIN and AGND is recommended.
Output Capacitor
The required output capacitance is determined by the output voltage of the TPS84610. See Table 3 for the
amount of required capacitance. The required output capacitance must include at least one 47 µF ceramic
capacitor. For applications where the ambient operating temperature is less than 0°C, an additional 100 µF
polymer-tantalum capacitor is recommended. When adding additional non-ceramic bulk capacitors, low-ESR
devices like the ones recommended in Table 4 are required. The required capacitance above the minimum is
determined by actual transient deviation requirements. See Table 5 for typical transient response values for
several output voltage, input voltage and capacitance combinations. Table 4 includes a preferred list of
capacitors by vendor.
Table 3. Required Output Capacitance
V_OUT RANGE (V)
MIN
MAX
0.8
< 1.8
1.8
< 3.3
3.3
3.6
MINIMUM REQUIRED C_OUT (µF)
147 ⁽¹⁾
100 ⁽²⁾
47 ⁽²⁾
(1) Minimum required must include at least 1 x 47 µF ceramic capacitor plus 1 x 100 µF polymer-tantalum
capacitor.
(2) Minimum required must include at least 47 µF of ceramic capacitance.
Copyright © 2011, Texas Instruments Incorporated
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