TAJA225K006RNJ AVX Corporation, TAJA225K006RNJ Datasheet - Page 7

• Manufacturer Part Number: TAJA225K006RNJ
• Description: CAP TANT 2.2UF 6.3V 10% SMD
• Manufacturer: AVX Corporation
• Series: TAJr
• Type: Moldedr

Specifications of TAJA225K006RNJ

• Capacitance: 2.2µF
• Package / Case: 1206 (3216 Metric)
• Voltage - Rated: 6.3V
• Tolerance: ±10%
• Operating Temperature: -55°C ~ 125°C
• Mounting Type: Surface Mount
• Size / Dimension: 0.126" L x 0.063" W (3.20mm x 1.60mm)
• Height: 0.063" (1.60mm)
• Manufacturer Size Code: A
• Features: General Purpose
• Tolerance (+ Or -): 10%
• Voltage: 6.3VDC
• Esr: 9Ohm
• Mounting Style: Surface Mount
• Polarity: Polar
• Construction: SMT Chip
• Case Style: Molded
• Case Code: A
• Lead Spacing (nom): Not Requiredmm
• Df: 6%
• Dcl: 0.5uA
• Seal: Not Required
• Insulation: Not Required
• Failure Rate: Not Required
• Wire Form: Not Required
• Product Length (mm): 3.2mm
• Product Height (mm): 1.6mm
• Product Depth (mm): 1.6mm
• Product Diameter (mm): Not Requiredmm
• Seated Plane Height: Not Requiredmm
• Length W/weld (max): Not Requiredmm
• Operating Temp Range: -55C to 125C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Spacing: -
• Esr (equivalent Series Resistance): -
• Lead Free Status / RoHS Status: Compliant, Lead free / RoHS Compliant
• Other names: TAJA225K006R; TAJA225K006R

Technical Summary and
Application Guidelines
INTRODUCTION
Tantalum capacitors are manufactured from a powder of
pure tantalum metal. The typical particle size is between 2
and 10 µm.
Figure below shows typical powders. Note the very great
difference in particle size between the powder CVs.
The powder is compressed under high pressure around a
Tantalum wire (known as the Riser Wire) to form a “pellet”.
The riser wire is the anode connection to the capacitor.
This is subsequently vacuum sintered at high temperature
(typically 1400 - 1800°C). This helps to drive off any impuri-
ties within the powder by migration to the surface.
During sintering the powder becomes a sponge like
structure with all the particles interconnected in a huge
lattice.
This structure is of high mechanical strength and density, but
is also highly porous giving a large internal surface area
(see Figure 2).
The larger the surface area the larger the capacitance. Thus
high CV (capacitance/voltage product) powders, which have
a low average particle size, are used for low voltage, high
capacitance parts.
By choosing which powder is used to produce each capac-
itance/voltage rating the surface area can be controlled.
The following example uses a 220µF 10V capacitor to
illustrate the point.
where
and
4000µFV
d is the dielectric thickness in meters
C is the capacitance in Farads
A is the surface area in meters
o
r is the relative dielectric constant for Tantalum
is the dielectric constant of free space
(8.855 x 10
Pentoxide (27)
-12
C = o r
Farads/m)
20000µFV
Figure 1.
d
A
50000µFV
Rearranging this equation gives:
thus for a 220µF 10V capacitor the surface area is 550
square centimeters, or nearly twice the size of this page.
The dielectric is then formed over all the tantalum surfaces
by the electrochemical process of anodization. To achieve
this, the “pellet” is dipped into a very weak solution of phos-
phoric acid.
The dielectric thickness is controlled by the voltage applied
during the forming process. Initially the power supply is kept
in a constant current mode until the correct thickness of
dielectric has been reached (that is the voltage reaches the
‘forming voltage’), it then switches to constant voltage mode
and the current decays to close to zero.
The chemical equations describing the process are as
follows:
The oxide forms on the surface of the Tantalum but it also
grows into the metal. For each unit of oxide two thirds grows
out and one third grows in. It is for this reason that there is a
limit on the maximum voltage rating of Tantalum capacitors
with present technology powders (see Figure 3).
The dielectric operates under high electrical stress. Consider
a 220µF 10V part:
Formation voltage
Anode:
Cathode:
Figure 2. Sintered Tantalum
2 Ta
2 Ta
10 H
= Formation Ratio x Working Voltage
= 3.5 x 10
= 35 Volts
5+
2
O – 10 e
+ 10 OH -
A =
2 Ta
5+
C d
o r
+ 10 e
5H
Ta
2
2
O
5
+ 10 OH -
+ 5 H
2
O
35