KEMET®
APPLICATION NOTES FOR TANTALUM CAPACITORS
temperature. Capacitance, DF, and DCL are measured
at each test temperature except that DCL is not
measured at -55°C.
ing by all popular machines known to KEMET at this time.
Most KEMET axial Series may be supplied on reels to feed
such machines. Radial leads are intended to plug directly
into holes of PC boards. Auto-machines will insert com-
batible radial capacitor designs, and most KEMET capac-
itors may be supplied in appropriate reeled forms (ARIS).
When measurements are made at the various steps, the
electrical limits for each temperature shall not exceed
the following limits.
With either axial or radial types, attention should be
paid to treatment of the capacitors during mounting and
afterward under service conditions. Difficulty during
mounting usually arises from lead damage or from over-
heating. Hand soldering technique or, more often, wave-
solder machines cause the overheating. The internal cath-
ode connection on most Series is made between solder
and a silver-pigmented paint. If too much heat is applied,
this solder may remelt and degrade the silver-solder inter-
face or cause a direct short-circuit.
KEMET’s hermetically-sealed series has an internal
space into which molten cathode solder may run, depriv-
ing the cathode connection and possibly flowing across
the terminals to short-circuit the capacitor from the inside.
It is also possible to remelt the solder which bonds the rim
of the glass-metal seal, causing loss of hermeticity and
possibly a short-circuit. Finally, solder at the exit point of
the positive wire may be remelted with similar effect. This
solder is a high-temperature alloy, however, and it is much
less likely to be melted. (Re-dipping of lead wires is prac-
ticed by some users, introducing another hazard of remelt-
ing this solder).
Plastic-encased Series have only one site of solder,
the internal cathode connection. The rate of heat transfer
through the plastic is lower than through the metal can of
hermetic Series, but conduction along the negative lead-
wire to remelt this solder is very similar. There is little inter-
nal void within plastic cases, so remelted solder tends to
remain in its original location and solidify when heat is
removed. Short-circuiting is very unlikely, but reliability of
the internal connection may be compromised by leaching
of silver from the paint into the molten solder. The latter
effect degrades the cathode connection in hermetic parts
as well.
Step 1, +25°C, DCL as indicated in original limit;
capacitance within tolerance speci-
fied; DF as indicated in original limit
shown in Part Number Tables.
Step 2, -55°C, Capacitance within ±10% of initial
value; ESR, DF within limit shown in
Part Number Tables.
Step 3, +25°C, DCL as indicated in original limit;
capacitance within ±5% of initial
value; ESR, DF within limit shown in
Part Number Tables.
Step 4, +85°C, DCL shall not exceed 10 times original
DCL limit at 25°C. Capacitance shall
be within ±10% of the initial value. DF
shall be within 125% of limits shown in
Part Number Tables. ESR shall be
within limits shown in Part Number
Tables.
Step 5, +125°C, DCL shall not exceed 12.5 times the
original limit at 25°C. Capacitance
shall be within ±12% of initial value.
DF shall be within 150% of limits
shown in Part Number Tables. ESR
shall be within limits shown in Part
Number Tables.
Step 6, +25°C, DCL as indicated in original limit;
capacitance within ±5% of initial
value; ESR, DF as indicated in origi-
nal limit shown in Part Number
Tables.
Note: M39003 specifies ∆'s and limits by individual slash
sheet.
• DAMP HEAT, STEADY STATE: Meets requirements of
IEC Publication 384-15, method IEC 68-2-3. Climatic
category 55/125/56.
All encased capacitors will pass the Resistance to
Soldering Heat Test of MIL-STD-202, Method 210,
Condition B. This test dips each leadwire into molten sol-
der at +260° C for 10 seconds while the capacitor body is
held vertically above the solder. KEMET capacitors will
pass this test when the depth of immersion brings the
capacitor body (or closest external solder joint, if it is clos-
er as in some hermetic Series) to a minimum distance of
0.100 inches from the solder surface. This demonstration
of resistance to solder heat is in accordance with what is
believed to be the industry standard. More severe treat-
ment must be considered reflective of an improper solder-
ing process.
19. MOUNTING
All encapsulated Series fall into two general classes.
The first is provided with leads extending from opposite
ends of the body, generally along the principle axis of the
body (“axial leads”). The second is provided with parallel
leads extending from one side or face of the body (“radial
leads”). With either type, mounting points are normally
provided by the leads themselves.
Axial leads may be used for point-to-point wiring, but
usually, the wires are bent at 90° from the capacitor axis
for insertion through printed circuit (PC) boards. Axial
capacitors supplied on reels for machine insertion will
withstand the mechanical stresses of bending and insert-
Shown in Figure 13 is a recommended solder wave
profile for both axial and radial leaded solid tantalum
capacitors.
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KEMET Electronics Corporation, P.O. Box 5928, Greenville, S.C. 29606 (864) 963-6300
KEMET [ KEMET CORPORATION ]
