PTH03060Y
PTH05060Y, PTH12060Y
SLTS222A – MARCH 2004 – REVISED OCTOBER 2005
www.ti.com
APPLICATION INFORMATION (continued)
Ceramic Capacitors
Above 150 kHz the performance of aluminum electrolytic capacitors becomes less effective. To further improve
the reflected input ripple current or the output transient response. Multilayer ceramic capacitors have very low
ESR and their 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. When used on the
output their combined ESR is not critical as long as the total value of ceramic capacitance does not exceed
300
µF.
Also, to prevent the formation of local resonances, do not place more than five identical ceramic
capacitors in parallel with values of 10
µF
or greater.
Tantalum Capacitors
Tantalum type capacitors can be used at both the input and output, and are recommended for applications where
the ambient operating temperature can be less than 0°C. The AVX TPS, Sprague 593D/594/595 and Kemet
T495/T510 capacitor series are suggested over many other tantalum types due to their higher rated surge, power
dissipation, and ripple current capability. As a caution many general purpose tantalum capacitors have
considerably higher ESR, reduced power dissipation and lower ripple current capability. These capacitors are
also less reliable when determining their power dissipation and surge current rating. Tantalum capacitors that do
not have a stated ESR or surge current rating are not recommended for power applications.
When specifying Os-Con and polymer tantalum capacitors for the output, the minimum ESR limit will be
encountered well before the maximum capacitance value is reached.
Capacitor Table
Table 1
identifies the characteristics of capacitors from a number of vendors with acceptable ESR and ripple
current (rms) ratings. The recommended number of capacitors required at both the input and output buses is
identified for each capacitor type.
This is not an extensive capacitor list. Capacitors from other vendors are available with comparable
specifications. Those listed are for guidance. The RMS ripple current rating and ESR (at 100 kHz) are critical
parameters necessary to insure both optimum regulator performance and long capacitor life.
Table 1. Input/Output Capacitors
(1)
Capacitor Characteristics
Capacitor Vendor,
Type/Series (Style)
Panasonic, Aluminum
FC (Radial)
FK (SMD)
FC (SMD)
United Chemi-Con
PXA, Poly-Aluminum (SMD)
PS, Poly-Aluminum (Radial)
LXZ, Aluminum (Radial)
Nichicon Aluminum
WG (SMD)
HD (Radial)
PM (Radial)
10
10
16
470
470
330
0.150
0.072
0.120
670
760
625
10×10
8×11.5
10×12,5
1
1
1
1
1
2
UWG1A471MNR1GS
UHD1A471MPR
UPM1C331MPH6
10
10
10
470
470
470
0.012
0.012
0.120
5300
5300
555
10×12,2
8×12,2
8×12
1
1
1
≤1
≤1
1
PXA10VC471MJ12TP
10PS470MJ12
LXZ10VB471M8X12LL
10
10
10
470
470
470
0.117
0.160
0.150
555
600
670
8×11,5
8×10,2
10×10,2
1
1
1
1
1
1
EEUFC1A471
EEVFK1A471P
EEVFC1A471P
Working
Voltage
(V)
Value
(µF)
Max ESR
at 100 kHz
(Ω)
Max Ripple
Current at 85°C
(Irms) (mA)
Physical
Size
(mm)
Quantity
Input
Bus
Output
Bus
Vendor
Part Number
(1)
Capacitor Supplier Verification
Please verify availability of capacitors identified in this table. Capacitor suppliers may recommend alternative part numbers because of
limited availability or obsolete products. In some instances, the capacitor product life cycle may be in decline and have short-term
consideration for obsolescence.
RoHS, Lead-free and Material Details
Please consult capacitor suppliers regarding material composition, RoHS status, lead-free status, and manufacturing process
requirements. Component designators or part number deviations can occur when material composition or soldering requirements are
updated.
8
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