BestCap
™
Ultra-low ESR High Power Pulse Supercapacitors
GENERAL DESCRIPTION
The BestCap
™
series of electrochemical supercapacitors offer excellent
high power pulse characteristics based upon the combination of very high
capacitance and ultra low ESR in the milliOhm region.
Based on a unique patented aqueous chemistry and an innovative design, the
system offers high capacitance, even with short pulse duration regimes such
as in GSM and PCS based systems, together with a variety of voltage ratings.
Depending upon package size, standard capacitance values of 30mF to
560mF are available in voltage ratings of 3.5V, 4.5V and 5.5V. ESR values
for these standard devices range from 25 milliOhm to 230 milliOhm.
Used in conjunction with battery packs, BestCap
™
improves the voltage
performance for high current pulses, resulting in higher PA efficiency and
longer battery talk-time as shown in Fig. 5. BestCap
™
can also be used to
boost instantaneous power availability in non-battery electronic applications
where low level constant currents need to be supplemented by high current pulses.
APPLICATIONS
RF Modems
Mainframe Computer Decoupling
Hybrid Battery Packs
Hearing Aids
Camera Flash Systems
Prosthetics
Audio System “Base Line Stiffeners” Wireless Alarm Systems
Systems/Products based on GSM/DSC1800/PCS/DECT/etc.
Memory Back-up
UPS
Switch Mode Power Supplies
PERFORMANCE CHARACTERISTICS & DIMENSIONS
AVX CATALOG PART NUMBER
BZ015B303Z_B27
BZ014B353Z_B24
BZ013B403Z_B21
BZ015A503Z_B35
BZ014A603Z_B32
BZ013A703Z_B29
BZ015B603Z_B48
BZ014B703Z_B43
BZ013B803Z_B38
BZ015A104Z_B61
BZ014A124Z_B55
BZ013A144Z_B47
Size
(mm)
28 x 17 x 2.7
28 x 17 x 2.4
28 x 17 x 2.1
28 x 17 x 3.5
28 x 17 x 3.2
28 x 17 x 2.9
28 x 17 x 4.8
28 x 17 x 4.3
28 x 17 x 3.8
28 x 17 x 6.1
28 x 17 x 5.5
28 x 17 x 4.7
Rated
Voltage
Volts
5.5
4.5
3.5
5.5
4.5
3.5
5.5
4.5
3.5
5.5
4.5
3.5
Capacitance
milli farads
+80%, -20%
30
35
40
50
60
70
60
70
80
100
120
140
ESR (ohms)
ohms
+/-20% @1khz
0.200
0.180
0.170
0.230
0.210
0.200
0.100
0.090
0.080
0.120
0.100
0.090
Leakage Current
milli amps
max
0.005
0.005
0.005
0.005
0.005
0.005
0.010
0.010
0.010
0.010
0.010
0.010
BZ025A204Z_B35
BZ024A234Z_B32
BZ023A284Z_B29
BZ025A404Z_B60
BZ024A474Z_B55
BZ023A564Z_B47
48 x 30 x 3.5
48 x 30 x 3.2
48 x 30 x 2.9
48 x 30 x 6.0
48 x 30 x 5.5
48 x 30 x 4.7
5.5
4.5
3.5
5.5
4.5
3.5
200
230
280
400
470
560
0.060
0.050
0.045
0.035
0.030
0.025
0.020
0.020
0.020
0.040
0.040
0.040
HOW TO ORDER
BZ
BESTCAP
™
01
CASE SIZE
Where:
01 = 28mm x 17mm
02 = 48mm x 30mm
5
VOLTAGE
Where
5 = 5.5 volts
4 = 4.5 volts
3 = 3.5 volts
A
A = Standard
B = Thin
503
CAPACITANCE VALUE (µF)
First two numbers express the significant digits;
the third number refers to the number of zeros.
Example: 503
➝
50,000µF = 50mF.
Z
CAPACITANCE
TOLERANCE
Where:
Z = +80%, -20%
A
TERMINATION
STYLE
Where:
A = Leaded
S = SMT
L = L lead
B
PACKAGE CODE
Where:
B = Bulk
35
MAXIMUM PART HEIGHT
Where:
29 = 2.9mm 42 = 4.2mm
32 = 3.2mm 53 = 5.3mm
35 = 3.5mm 60 = 6.0mm
BESTCAP
™
: A NEW GENERATION OF PULSE SUPERCAPACITORS
Supercapacitors, (also referred to as Electrochemical Capacitors or Double Layer Capacitors) have rapidly
become recognized, not only as an excellent compromise between “electronic” capacitors such as ceramic,
tantalum, film and aluminium electrolytic, and batteries (Fig. 1), but also as a valuable technology for providing
a unique combination of characteristics, particularly very high energy, power and capacitance densities.
Fig. 1 Specific Energy of Capacitor Types
10000
Specific Energy
(mFV/cc)
SPECIFIC ENERGY
1000
100
TA
AL
NT
UM
ER IC
YM YT
OL ROL M
P T
U
INI
EC
EL LUM
A
ELECTROLYTIC
CAPACITOR
10
0.1
1
10
100
1000
1
10000
Capacitance (mF)
There are however, two negative characteristics associated with conventional supercapacitors, viz: high ESR in
the Ohms or tens of Ohms area, and severe capacitance loss when called upon to supply very short duration
current pulses. BestCap
™
successfully addresses both of these drawbacks.
This capacitance loss in the millisecond region is caused by the charge transfer (i.e. establishment of
capacitance) being carried out primarily by relatively slow moving ions in double layer capacitors. In the
above-mentioned “electronic” capacitors, the charge transfer is performed by fast electrons, thereby creating
virtually instant rated capacitance value. Fig. 2 illustrates the severe capacitance loss experienced by several
varieties of supercapacitors (N, M & P), under short pulse width conditions. It can also be seen from Fig. 2,
how well BestCap
™
retains its capacitance with reducing pulse widths.
Fig. 2 Actual capacitance vs. pulse width
100%
80%
60%
40%
20%
0%
1000
100
Pulse Width (msec)
10
1
Actual Cap. (% of Nominal)
EDLC=Electrochemical
double layer capacitor
Aluminium Electroytic Capacitor
manufacturer A EDLC
manufacturer B EDLC
manufacturer C EDLC
For comparison purposes, the characteristic of an equivalent capacitance value aluminium electrolytic capacitor
is shown in Fig. 3. The electrolytic capacitor is many times the volume of the BestCap
™
.
Fig. 3 Sized comparison, BestCap
™
vs aluminium electrolytic capacitor
VOLTAGE DROP
Two factors are critical in determining voltage drop when a capacitor delivers a short current pulse; these are
ESR and “available” capacitance as shown in Fig. 4.
Fig 4 Voltage-time relation of capacitor unit
Vo
vV(IR)
vVtotal=I*R
+ I*vt/C(vt)
vV(Q)=I* vt/C(vt)
Vt
vt
The instant voltage drop
v
V (IR) is caused by and is directly proportional to the capacitor’s ESR. The
continuing voltage drop with time
v
V (Q), is a function of the available charge, i.e. capacitance.
From figures 3 and 4, it is apparent that, for very short current pulses, e.g. in the millisecond region, the
combination of voltage drops in a conventional supercapacitor caused by a) the high ESR and b) the lack of
available capacitance, causes a total voltage drop, unacceptable for most applications. Now compare the
BestCap
™
performance under such pulse conditions. The ultra-low, (milliOhm), ESR minimizes the
instantaneous voltage drop, while the very high retained capacitance drastically reduces the severity of the
charge related drop.
EFFICIENCY/TALKTIME BENEFITS OF BESTCAP
™
Because BestCap
™
, when used in parallel with a battery, provides a current pulse with a substantially higher
voltage than that available just from the battery as shown in Fig. 5, the efficiency of the RF power amplifier
is improved.
Fig. 5 GSM Pulse
4
Battery Voltage (Volts)
3.8
3.6
3.4
3.2
3
0
1000
2000
Time (uSeconds)
Battery Voltage
Battery and Capacitor Voltage
Current Pulse
3000
4000
5
4
3
2
1
0
Current (Amps)
Additionally, the higher-than battery voltage supplied by the BestCap
™
keeps the voltage pulse above the
“cut off voltage” limit for a significantly longer time than is the case for the battery alone. This increase in
“talktime” is demonstrated in figures 6a) (Li-Ion at +25°C); 6b) (Li-Ion at 0°C); 6c) (Ni-MH at +25°C) & 6d)
(Ni-MH at 0°C).
Fig. 6a Li-ION Battery
Cutoff Voltage Limits
4
Voltage (Volts)
3.5
Cutoff Voltage
3.4 Volts
3.5 Volts
% Increase
28%
73%
300%
3
2.5
3.6 Volts
Fig. 6b Battery Life at 0°C
300
400
4
Battery Alone
Voltage (Volts)
3.5
LI-ION Battery
2
0
100
200
Time (Minutes)
Battery with Pulse Capacitor
GSM Pulse @ 2 Amps
3
2.5
Cutoff Voltage
3.4 Volts
3.5 Volts
3.6 Volts
% Increase
83%
160%
900%
2
Fig. 6c NI-MH Battery
6
0
100
200
Time (Minutes)
300
400
500
Battery with Pulse Capacitor
Battery Alone
GSM Pulse @ 2 Amps 0 Deg C
Voltage (Volts)
5
4
Cutoff Voltage
4.3 Volts
% Increase
13%
118%
960%
3
4.4 Volts
4.5 Volts
Fig. 6d Battery Life at 0°C
150
Battery Only
Voltage (Volts)
5
200
NI-MH Battery
6
2
0
50
100
Time (Minutes)
Battery and Capacitor
GSM Pulse @ 2 Amps
4
Cutoff Voltage
4.3 Volts
4.4 Volts
4.5 Volts
% Increase
600%
3500%
4900%
3
2
0
50
Time (Minutes)
100
150
200
Battery Alone
250
Battery with Pulse Capacitor
GSM Pulse @ 2 Amps 0 Deg C
