Low Inductance Capacitors
Introduction
As switching speeds increase and pulse rise times decrease
the need to reduce inductance becomes a serious limitation
for improved system performance. Even the decoupling
capacitors, that act as a local energy source, can generate
unacceptable voltage spikes: V = L (di/dt). Thus, in high
speed circuits, where di/dt can be quite large, the size of the
voltage spike can only be reduced by reducing L.
Figure 1 displays the evolution of ceramic capacitor toward
lower inductance designs over the last few years. AVX has
been at the forefront in the design and manufacture of these
newer more effective capacitors.
2000
1500
INTERDIGITATED CAPACITORS
Multiple terminations of a capacitor will also help in reducing
the parasitic inductance of the device. The IDC is such a
device. By terminating one capacitor with 8 connections the
ESL can be reduced even further. The measured inductance
of the 0612 IDC is 60 pH, while the 0508 comes in around
50 pH. These FR4 mountable devices allow for even higher
clock speeds in a digital decoupling scheme. Design and
product offerings are shown on pages 48 and 49.
SpinGuard
2000 pH
-
+
-
+
1206 MLC
1000
pH
1200 pH
500
0508 LICC
130 pH
0306 LICC
105pH
60 pH
0612
IDC
0508 IDC
LICA
50 pH
25 pH
LOW INDUCTANCE CHIP ARRAYS (LICA
®
)
Further reduction in inductance can be achieved by designing
alternative current paths to minimize the mutual inductance
factor of the electrodes (Figure 3). This is achieved by AVX’s
LICA
®
product which was the result of a joint development
between AVX and IBM. As shown in Figure 4, the charging
current flowing out of the positive plate returns in the opposite
direction along adjacent negative plates. This minimizes the
mutual inductance.
The very low inductance of the LICA capacitor stems from
the short aspect ratio of the electrodes, the arrangement of
the tabs so as to cancel inductance, and the vertical aspect
of the electrodes to the mounting surface.
0
1980s
1990s
Figure 1. The evolution of Low Inductance Capacitors at AVX
(values given for a 100 nF capacitor of each style)
LOW INDUCTANCE CHIP CAPACITORS
The total inductance of a chip capacitor is determined both
by its length to width ratio and by the mutual inductance
coupling between its electrodes. Thus a 1210 chip size has
lower inductance than a 1206 chip. This design improve-
ment is the basis of AVX’s low inductance chip capacitors, LI
Caps, where the electrodes are terminated on the long side
of the chip instead of the short side. The 1206 becomes an
0612 as demonstrated in Figure 2. In the same manner, an
0805 becomes an 0508 and 0603 becomes an 0306. This
results in a reduction in inductance from around 1200 pH
for conventional MLC chips to below 200 pH for Low
Inductance Chip Capacitors. Standard designs and perfor-
mance of these LI Caps are given on pages 46 and 47.
Charges entering - plate
Charges entering - plate
Charges leaving + plate
Net
Inductance
Net
Inductance
1206
0612
Figure 2. Change in aspect ratio: 1206 vs. 0612
Figure 3. Net Inductance from design. In the
standard Multilayer capacitor, the charge currents
entering and leaving the capacitor create complementary
flux fields, so the net inductance is greater. On the right,
however, if the design permits the currents
to be opposed, there is a net cancellation, and the
inductance is much lower.
44
Charges leaving + plate
-
+
170 pH
+
-
0612 LICC
Low Inductance Capacitors
Introduction
Also the effective current path length is minimized because
the current does not have to travel the entire length of both
electrodes to complete the circuit. This reduces the self
inductance of the electrodes. The self inductance is also min-
imized by the fact that the charging current is supplied by
both sets of terminals reducing the path length even further!
The inductance of this arrangement is less than 30 pH,
causing the self-resonance to be above 100 MHz for the
same popular 100 nF capacitance. Parts available in the
LICA design are shown on pages 50 and 51.
Figure 5 compares the self resonant frequencies of various
capacitor designs versus capacitance values. The approxi-
mate inductance of each style is also shown.
Figure 4. LICA’s Electrode/Termination Construction.
The current path is minimized – this reduces self-inductance.
Current flowing out of the positive plate, returns in the
opposite direction along the adjacent negative plate –
this reduces the mutual inductance.
Active development continues on low inductance
capacitors. C4 termination with low temperature solder
is now available for plastic packages. Consult AVX
for details.
1000.00
LICA (25 pH)
0508 IDC (50 pH)
Self Resonant Frequency (MHz)
0612 IDC (60 pH)
100.00
0306 LICC (110 pH)
0508 LICC (130 pH)
0612 LICC (170 pH)
0603 (700 pH)
0805 (800 pH)
10.00
1206 (1200 pH)
1.00
10.00
100.00
Capacitance, (nF)
1000.00
Figure 5. Self Resonant Frequency vs. Capacitance and Capacitor Design
45
Low Inductance Capacitors
0612/0508/0306 LICC (Low Inductance Chip Capacitors)
GENERAL DESCRIPTION
The total inductance of a chip capacitor is determined both by its
length to width ratio and by the mutual inductance coupling
between its electrodes.
Thus a 1210 chip size has a lower inductance than a 1206 chip.
This design improvement is the basis of AVX’s Low Inductance
Chip Capacitors (LICC), where the electrodes are terminated on the
long side of the chip instead of the short side. The 1206 becomes
an 0612, in the same manner, an 0805 becomes an 0508, an 0603
becomes an 0306. This results in a reduction in inductance from
the 1nH range found in normal chip capacitors to less than 0.2nH
for LICCs. Their low profile is also ideal for surface mounting (both
on the PCB and on IC package) or inside cavity mounting on the
IC itself.
MLCC
LICC
HOW TO ORDER
0612
Size
0306
0508
0612
Z
Voltage
6 = 6.3V
Z = 10V
Y = 16V
3 = 25V
5 = 50V
D
Dielectric
C = X7R
D = X5R
105
Capacitance
Code (In pF)
2 Sig. Digits +
Number of Zeros
M
Capacitance
Tolerance
K = ±10%
M = ±20%
A
Failure Rate
A = N/A
T
Terminations
T = Plated Ni
and Sn
J = Tin/Lead
2
Packaging
Available
2 = 7" Reel
4 = 13" Reel
A*
Thickness
Thickness
mm (in)
0.56 (0.022)
0.61 (0.024)
0.76 (0.030)
1.02 (0.040)
1.27 (0.050)
PERFORMANCE CHARACTERISTICS
Capacitance Tolerances
Operation
Temperature Range
Temperature Coefficient
Voltage Ratings
Dissipation Factor
Insulation Resistance
K = ±10%; M = ±20%
X7R = -55°C to +125°C;
X5R = -55°C to +85°C
±15% (0VDC)
6.3, 10, 16, 25 VDC
6.3V = 6.5% max; 10V = 5.0% max;
16V = 3.5% max; 25V = 3.0% max
100,000MΩ min, or 1,000MΩ per
µF min.,whichever is less
TYPICAL INDUCTANCE
Package Style
1206 MLCC
0612 LICC
0508 LICC
0306 LICC
*Note: See Range Chart for Codes
Measured
Inductance (pH)
1200
170
130
105
(@+25°C, RVDC)
TYPICAL IMPEDANCE CHARACTERISTICS
10
10
Impedance (Ohms)
Impedance (Ohms)
MLCC_0805
1
MLCC_1206
1
0.1
LICC_0508
0.1
LICC_0612
0.01
0.01
0.001
1
10
100
1000
0.001
1
10
100
1000
Frequency (MHz)
Frequency (MHz)
46
Low Inductance Capacitors
0612/0508/0306 LICC (Low Inductance Chip Capacitors)
SIZE
Packaging
Length
Width
MM
(in.)
MM
(in.)
0306
Embossed
0.81 ± 0.15
(0.032 ± 0.006)
1.60 ± 0.15
(0.063 ± 0.006)
0508
Embossed
1.27 ± 0.25
(0.050 ± 0.010)
2.00 ± 0.25
(0.080 ± 0.010)
0612
Embossed
1.60 ± 0.25
(0.063 ± 0.010)
3.20 ± 0.25
(0.126 ± 0.010)
PHYSICAL DIMENSIONS AND
PAD LAYOUT
W
t
WVDC
CAP
(uF)
0.001
0.0022
0.0047
0.010
0.015
0.022
0.047
0.068
0.10
0.15
0.22
0.47
0.68
1.0
1.5
2.2
3.3
4.7
10
6.3 10 16
25 50 6.3 10 16 25 50 6.3 10 16 25 50
T
L
PHYSICAL CHIP DIMENSIONS
L
0612
0508
0306
1.60 ± 0.25
(0.063 ± 0.010)
1.27 ± 0.25
(0.050 ± 0.010)
0.81 ± 0.15
(0.032 ± 0.006)
mm (in)
t
0.13 min.
(0.005 min.)
0.13 min.
(0.005 min.)
0.13 min.
(0.005 min.)
W
3.20 ± 0.25
(0.126 ± 0.010)
2.00 ± 0.25
(0.080 ± 0.010)
1.60 ± 0.15
(0.063 ± 0.006)
T - See Range Chart for Thickness and Codes
PAD LAYOUT DIMENSIONS
A
0612
0508
0306
mm (in.)
mm (in)
C
.635 (0.025)
0.51 (0.020)
0.51 (0.020)
B
3.05 (0.120)
2.03 (0.080)
1.52 (0.060)
0.76 (0.030)
0.51 (0.020)
0.31 (0.012)
Solid = X7R
mm (in.)
= X5R
mm (in.)
0306
Code Thickness
A
0.61 (0.024)
S
V
A
0508
Code Thickness
0.56 (0.022)
0.76 (0.030)
1.02 (0.040)
S
V
W
A
0612
Code Thickness
0.56 (0.022)
0.76 (0.030)
1.02 (0.040)
1.27 (0.050)
“B”
C
“A”
C
47
Packaging of Chip Components
Automatic Insertion Packaging
TAPE & REEL QUANTITIES
All tape and reel specifications are in compliance with RS481.
8mm
Paper or Embossed Carrier
Embossed Only
Paper Only
Qty. per Reel/7" Reel
Qty. per Reel/13" Reel
0201, 0306, 0402, 0603
2,000, 3,000 or 4,000, 10,000, 15,000
Contact factory for exact quantity
12mm
0612, 0508, 0805, 1206,
1210
1808
1812, 1825
2220, 2225
500, 1,000
Contact factory for exact quantity
3,000
10,000
5,000, 10,000, 50,000
Contact factory for exact quantity
4,000
REEL DIMENSIONS
Tape
Size
(1)
8mm
A
Max.
B*
Min.
C
D*
Min.
N
Min.
W
1
-0.0
8.40
+1.5
+0.059
(0.331
-0.0
)
W
2
Max.
14.4
(0.567)
W
3
7.90 Min.
(0.311)
10.9 Max.
(0.429)
11.9 Min.
(0.469)
15.4 Max.
(0.607)
330
(12.992)
12mm
1.5
(0.059)
13.0
+0.50
-0.20
-0.008
(0.512
+0.020
)
20.2
(0.795)
50.0
(1.969)
-0.0
12.4
+2.0
-0.0
(0.488
+0.079
)
18.4
(0.724)
Metric dimensions will govern.
English measurements rounded and for reference only.
(1) For tape sizes 16mm and 24mm (used with chip size 3640) consult EIA RS-481 latest revision.
60
嵌入式系统
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