BZ05FB682ZSB AVX Corporation, BZ05FB682ZSB Datasheet - Page 23

• Manufacturer Part Number: BZ05FB682ZSB
• Description: CAP 6.8MF 15V CARBON SMD
• Manufacturer: AVX Corporation
• Series: BestCap® BZr

Specifications of BZ05FB682ZSB

• Capacitance: 6.8mF
• Tolerance: -20%, +80%
• Voltage - Rated: 15V
• Height: 0.228" (5.80mm)
• Size / Dimension: 0.787" L x 0.591" W (20.00mm x 15.00mm)
• Operating Temperature: -20°C ~ 70°C
• Esr (equivalent Series Resistance): 500.0 mOhm
• Lifetime @ Temp.: 1000 Hrs @ 70°C
• Mounting Type: Surface Mount
• Package / Case: 3 Lead BZ05
• Voltage Rating: 15 Volts
• Esr: 600 mOhms
• Operating Temperature Range: - 20 C to + 70 C
• Dimensions: 15 mm W x 20 mm L x 2.3 mm to 6.5 mm H
• Leakage Current: 10 uAmps
• Product: Super Capacitors
• Capacitance Tolerance: +80, -20%
• Capacitor Mounting: SMD
• No. Of Pins: 3
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Spacing: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 478-6277

4.4 BESTCAP FOR GSM/GPRS PCMCIA
MODEMS
There is an increasing usage of PCMCIA modem cards for
wireless LAN and WAN (Wide Area Network) applications.
The PCMCIA card is used as an accessory to Laptops and
PDA’s, and enables wide area mobile Internet access,
including all associated applications like Email and file
transfer.
With the wide spread use of GSM networks, a PCMCIA
GSM modem is a commonly used solution. To achieve
higher speed data rates, GSM networks are now being
upgraded to support the GPRS standard.
The design challenge:
GSM/GPRS transmission requires a current of approximate-
ly 2A for the pulse duration. The PCMCIA bus cannot supply
this amount of pulsed current. Therefore, there is a need for
a relatively large capacitance to bridge the gap.
The capacitor supplies the pulse current to the transmitter,
and is charged by a low current during the interval between
pulses.
22
BestCap
High Power Pulse Supercapacitors
V
PCMCIA bus
+
from
Current
Voltage
2 Ampere
Capacitor
®
Ultra-low ESR
Transmitter
* V=V
THE SOLUTION:
It is assumed that during the pulse, 0.5A is delivered by the
battery, and 1.5A by the capacitor.
Conclusion: High capacitance is needed to minimize voltage
drop. A high value capacitance, even with a higher ESR,
results in a lower voltage drop. Low voltage drop minimizes
the conductive and emitted electro magnetic interference,
and increases transmitter output power and efficiency.
Voltage After Pulse (V)
Operating Voltage (V)
Rated Capacitance
@ 0.5msec Pulse
Cutoff Voltage (V)
Voltage Drop* (V)
(25% duty cycle)
V
Capacitance
GPRS Pulse
(milli Farad)
(milli Farad)
1
(milli ohm)
Pass/FAIL
Size (mm)
+V
ESR
2
=1.5A*ESR + (1.5A*1.154msec)/C
Chip Tantalum
SOLUTION A
.4 x 7 x 2
0.804V
2.896
FAIL
2.2
2.2
3.7
3.1
50
}
}
V
V
BZ154B473ZSB
SOLUTION B
1
2
20 x 15 x 2.1
BestCap
= I*ESR
= I* t/C
0.268V
3.432
PASS
160
3.7
3.1
t
47
30
®