GENERAL DESCRIPTION
The BestCapseries 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, BestCapimproves the voltage
performance for high current pulses, resulting in higher PA efficiency and
longer battery talk-time as shown in Fig. 5. BestCapcan 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 Memory Back-up
Hybrid Battery Packs Hearing Aids UPS
Camera Flash Systems Prosthetics Switch Mode Power Supplies
Audio System “Base Line Stiffeners” Wireless Alarm Systems
Systems/Products based on GSM/DSC1800/PCS/DECT/etc.
PERFORMANCE CHARACTERISTICS & DIMENSIONS
BestCapUltra-low ESR High Power Pulse Supercapacitors
BZ015B303Z_B27 28x1 7 x2.7 5.5 30 0.200 0.005
BZ014B353Z_B24 28x1 7 x2.4 4.5 35 0.180 0.005
BZ013B403Z_B21 28x1 7 x2.1 3.5 40 0.170 0.005
BZ015A503Z_B35 28x1 7 x3.5 5.5 50 0.230 0.005
BZ014A603Z_B32 28x1 7 x3.2 4.5 60 0.210 0.005
BZ013A703Z_B29 28x1 7 x2.9 3.5 70 0.200 0.005
BZ015B603Z_B48 28x1 7 x4.8 5.5 60 0.100 0.010
BZ014B703Z_B43 28x1 7 x4.3 4.5 70 0.090 0.010
BZ013B803Z_B38 28x1 7 x3.8 3.5 80 0.080 0.010
BZ015A104Z_B61 28x1 7 x6.1 5.5 100 0.120 0.010
BZ014A124Z_B55 28x1 7 x5.5 4.5 120 0.100 0.010
BZ013A144Z_B47 28x1 7 x4.7 3.5 140 0.090 0.010
BZ025A204Z_B35 48x30x3.5 5.5 200 0.060 0.020
BZ024A234Z_B32 48x30x3.2 4.5 230 0.050 0.020
BZ023A284Z_B29 48x30x2.9 3.5 280 0.045 0.020
BZ025A404Z_B60 48x30x6.0 5.5 400 0.035 0.040
BZ024A474Z_B55 48x30x5.5 4.5 470 0.030 0.040
BZ023A564Z_B47 48x30x4.7 3.5 560 0.025 0.040
Size
(mm) Rated
Voltage
Volts
Capacitance
milli farads
+80%, -20%
ESR (ohms)
ohms
+/-20% @1khz
Leakage Current
milli amps
max
AVX CATALOG PART NUMBER
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.
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. BestCapsuccessfully addresses both of these drawbacks.
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
HOW TO ORDER
ELECTROLYTIC
CAPACITOR
POLYMER
ELECTROLYTIC
ALUMINIUM
TANTALUM
100
10
1
10001001010.1 10000
1000
10000
SPECIFIC ENERGY
Fig. 1 Specific Energy of Capacitor Types
Capacitance (mF)
Specific Energy
(mFV/cc)
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.
0%
20%
40%
60%
80%
100%
1000 100
Actual Cap. (% of Nominal)
Pulse Width (msec) 10 1
Fig. 2 Actual capacitance vs. pulse width
Fig. 3 Sized comparison, BestCapvs aluminium electrolytic capacitor
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 BestCapretains its capacitance with reducing pulse widths.
EDLC=Electrochemical
double layer capacitor
manufacturer A EDLC
Aluminium Electroytic Capacitor
manufacturer B EDLC
manufacturer C EDLC
The instant voltage drop V (IR) is caused by and is directly proportional to the capacitor s ESR. The
continuing voltage drop with time 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
BestCapperformance 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.
3.6
3.4
3.2
30 1000 2000 3000 4000
3.8
4
3
2
1
0
4
5
Battery Voltage (Volts)
Current (Amps)
Time (uSeconds)
Battery Voltage Battery and Capacitor Voltage Current Pulse
Fig. 5 GSM Pulse
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.
Vo
Vt
t
V(IR)
V(Q)=I*
t/C(
t)
Vtotal=I*R + I*
t/C(
t)
Fig 4 Voltage-time relation of capacitor unit
2
2.5
3
3.5
4
0 100 200 300 400
Cutoff Voltage Limits
Voltage (Volts)
Cutoff Voltage
3.4 Volts
3.5 Volts
3.6 Volts
Time (Minutes)
% Increase
28%
73%
300%
Battery AloneBattery with Pulse Capacitor
GSM Pulse @ 2 Amps
2
2.5
3
3.5
4
0 100 200 300 400 500
LI-ION Battery
Voltage (Volts)
Cutoff Voltage
3.4 Volts
3.5 Volts
3.6 Volts
Time (Minutes)
% Increase
83%
160%
900%
Battery AloneBattery with Pulse Capacitor
GSM Pulse @ 2 Amps 0 Deg C
2
3
4
5
6
0 50 100 150 200 250
NI-MH Battery
Voltage (Volts)
Time (Minutes)
Cutoff Voltage
4.3 Volts
4.4 Volts
4.5 Volts
% Increase
600%
3500%
4900%
Battery AloneBattery with Pulse Capacitor
GSM Pulse @ 2 Amps 0 Deg C
2
3
4
5
6
0 50 100 150 200
Voltage (Volts)
Cutoff Voltage
4.3 Volts
4.4 Volts
4.5 Volts
Time (Minutes)
% Increase
13%
118%
960%
Battery OnlyBattery and Capacitor
GSM Pulse @ 2 Amps
Additionally, the higher-than battery voltage supplied by the BestCapkeeps 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
Fig. 6b Battery Life at 0°C
Fig. 6c NI-MH Battery
Fig. 6d Battery Life at 0°C
BESTCAPINRUSH CURRENT/SHORT CIRCUIT DISCHARGE CAPABILITIES
Testing of capacitors, including supercapacitors, is normally carried out using milliAmpere signals. However,
for many applications it is important to know the true capability of the device in terms of inrush and discharge
currents. In Figs. 7 & 8, shown below, show BestCapcharging to 10 Amps max., (28 x 17mm version) and
discharging with a peak current of 25 Amps (48 x 30mm version) into a load impedance of approximately
70 milliOhms.
Charging to 5.5V with maximum current of 10Amps.
Current
-10
-8
-6
-4
-2
0
2
4
6
8
10
20ms/Div.
2AMPS/Div.
Voltage
-5
-4
-3
-2
-1
0
1
2
3
4
5
20ms/Div.
1V/Div
Current
5ms/Div.
5A/Div.
Voltage
-1V
9V
5msec/Div.
1V/Div
Discharge into load of 70 milliOhms; peak current = 25Amps.
These figures graphically illustrate the exceptional peak current handling capabilities of BestCap.
Fig. 7 Inrush Characteristics
Fig. 8 Short-Circuit Discharge Characteristics
Back-up time of the BestCap™ may be calculated using the
following formula:
C = I * t /
V
V = Vo – Vt – I * RESR
At low current (as is the case in the back-up application):
V= Vo Vt
t = C
V/I = C*(Vo – Vt)/I
Where
C is the Capacitance in F
Vo is the initial voltage
Vt is the end voltage
I is the back-up current drain in Amperes
RESR is the ESR in Ohms
t = back-up time in seconds
Example: System Clock Time Maintenance
Using a BZ015A503ZAB35 BestCap™ 5.5V, 50mF, 28 x 17 footprint, 3.5 mm (max) height
If Vo = 5.0V Vt = 2.5V I(Back-up) = 40µA (40*10 –6 Amp.)
The discharge current of the Cap shall be the sum of the back-up current drain plus leakage current.
Leakage Current is a function of the Capacitor voltage. In the specific case,
the Leakage Current is 5µA at 5.0V and it comes down to <1µA at 2.5V.
In the “worst” case the Leakage Current = 5µA. Practically, the Leakage Current is 3µA[(5+1)/2].
The total discharge current during the back-up period is
40µA (back-up) + 5µA (Leakage Current) = 45µA, in the worst case, or
40µA (back-up) + 3µA (Leakage Current) = 43µA, practically.
Thus the back-up time would be:
t= 50*10–3 * (5–2.5)/45*10–6 = 46 minutes
Engineering Guidance Notes
1. Operational and storage temperature
-20°C to +70°C. Storage at room temperature is
recommended.
2. Voltage
Rated voltage of the capacitor is per the data sheet and
the label on the product. A surge voltage of V rated
+2% may be applied to the capacitor for <5 sec without
damage or performance degradation.
3. Temperature/Voltage Recommendations
Temperature -20°C to +35°C +35°C to +70°C
Rated Voltage Recommended Maximum Applied Voltage
3.5V 3.5V 3.2V
4.5V 4.5V 4.2V
5.5V 5.5V 5.0V
4. Polarity
BestCapcapacitors are non-polar, so can handle both
positive and negative voltages. The polarity marking on
the label relates to internal test procedures only and may
be ignored in normal use.
5. Mounting
BestCapmay not be reflow or wave soldered. Hand
soldering of the device is acceptable. When hand
soldering, use a soldering iron of <30W rating and ensure
that the tip temperature does not exceed +350°C.
Duration of the soldering operation should be <3 sec.
Mounting chips which may be automatically placed, (i.e.
via Pick n’ Place machine) and reflow soldered, and into
which the BestCapmay subsequently be inserted, are
available for some versions of BestCap. Please check
with your AVX Sales Office for further information.
6. Other Precautions
Do not disassemble the capacitor
Do not dispose of the capacitor by incineration.
Should the internal material come in contact with the
skin or eyes, wash/rinse thoroughly with running
water.
BESTCAPIN BATTERY BACK-UPAPPLICATIONS
BestCapis normally utilized as a power-boosting device to assist the main battery during pulse power
demand periods. However, the capacitor may also be used as a back-up unit when, for example, the battery is
being replaced.
Other BestCapCharacteristics
The material systems used in the Bestcap structure features the following characteristics:
Completely non-toxic.
Capable of very thin formats.
Shock resistance to >30000G’s.
Various voltage ratings.
Non-Polar.
Low leakage current <0.2µA/mF.
Capacitance values 30-560mF.
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BESTCAP 2.5k 0501