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參數(shù)資料
| 型號： | ICL7660CPA |
| 廠商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | Switched-Capacitor Voltage Converters |
| 中文描述： | SWITCHED CAPACITOR CONVERTER, 10 kHz SWITCHING FREQ-MAX, PDIP8 |
| 封裝： | PLASTIC, DIP-8 |
| 文件頁數(shù)： | 8/12頁 |
| 文件大?。?/td> | 116K |
| 代理商： | ICL7660CPA |
M
a function of oscillator frequency and the capacitor
value. Oscillator frequency, in turn, is influenced by
temperature and supply voltage. For example, with a
5V input voltage and 10μF charge-pump capacitors,
the output resistance is typically 50
. Thus, the output
voltage is about -5V under light loads, and decreases
to about -4.5V with a 10mA load current.
Minor supply voltage variations that are inconsequential
to digital circuits can affect some analog circuits.
Therefore, when using the MAX1044/ICL7660 for
powering sensitive analog circuits, the power-supply
rejection ratio of those circuits must be considered.
The output ripple and output drop increase under
heavy loads. If necessary, the MAX1044/ICL7660 out-
put impedance can be reduced by paralleling devices,
increasing the capacitance of C1 and C2, or connect-
ing the MAX1044’s BOOST pin to V+ to increase the
oscillator frequency.
Inrush Current and EMI Considerations
During start-up, pump capacitors C1 and C2 must be
charged. Consequently, the MAX1044/ICL7660 devel-
op inrush currents during start-up. While operating,
short bursts of current are drawn from the supply to C1,
and then from C1 to C2 to replenish the charge drawn
by the load during each charge-pump cycle. If the
voltage converters are being powered by a high-
impedance source, the supply voltage may drop too
low during the current bursts for them to function prop-
erly. Furthermore, if the supply or ground impedance is
too high, or if the traces between the converter IC and
charge-pump capacitors are long or have large loops,
switching noise and EMI may be generated. To reduce
these effects:
1) Power the MAX1044/ICL7600 from a low-impedance
source.
2) Add a power-supply bypass capacitor with low
effective series resistance (ESR) close to the IC
between the V+ and ground pins.
3) Shorten traces between the IC and the charge-pump
capacitors.
4) Arrange the components to keep the ground pins of
the capacitors and the IC as close as possible.
5) Leave extra copper on the board around the voltage
converter as power and ground planes. This is
easily done on a double-sided PC board.
Effic ienc y, Output Ripple,
and Output Impedanc e
The power efficiency of a switched-capacitor voltage
converter is affected by the internal losses in the con-
verter IC, resistive losses of the pump capacitors, and
conversion losses during charge transfer between the
capacitors. The total power loss is:
P = P +P +P +P
LOSSES
LOSSES
The internal losses are associated with the IC’s internal
functions such as driving the switches, oscillator, etc.
These losses are affected by operating conditions such
as input voltage, temperature, frequency, and connec-
tions to the LV, BOOST, and OSC pins.
The next two losses are associated with the output
resistance of the voltage converter circuit. Switch losses
occur because of the on-resistances of the MOSFET
switches in the IC. Charge-pump capacitor losses
occur because of their ESR. The relationship between
these losses and the output resistance is as follows:
where:
and f
OSC
is the oscillator frequency.
R
1
(f
4 2R
/ 2) x C1
ESR
ESR
OUT
OSC
SWITCHES
C1
C2
+
+
)
+
P
CAPACITOR
LOSSES
P
LOSSES
I
x R
OUT2
OUT
+
=
∑
S witc hed-Capac itor Voltage Converters
8
_______________________________________________________________________________________
MAX1044
ICL7660
4
3
10μF
V
OUT
=
-(V+)
10μF
V+
V+
CMOS or
TTL GATE
10k
REQUIRED
FOR TTL
2
1
5
6
7
8
Figure 7. External Clocking
CAPACITOR
LOSSES
CONVERSION
LOSSES
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| ICL7660CPA+ | 功能描述:電荷泵 Switched-Capacitor Voltage Converter RoHS:否 制造商:Maxim Integrated 功能:Inverting, Step Up 輸出電壓:- 1.5 V to - 5.5 V, 3 V to 11 V 輸出電流:100 mA 電源電流:1 mA 最大工作溫度:+ 70 C 封裝 / 箱體:SOIC-8 Narrow 封裝:Tube |
| ICL7660CPA+ | 制造商:Maxim Integrated Products 功能描述:IC CHARGE PUMP CONVERTER 8-DIP |
| ICL7660CPA115 | 制造商:Rochester Electronics LLC 功能描述:- Bulk |
| ICL7660CPAR2207 | 制造商:Rochester Electronics LLC 功能描述:- Bulk |
| ICL7660CPAZ | 功能描述:電荷泵 W/ANNEAL CMOS VOLT CONVRTR 8 PDIP COM RoHS:否 制造商:Maxim Integrated 功能:Inverting, Step Up 輸出電壓:- 1.5 V to - 5.5 V, 3 V to 11 V 輸出電流:100 mA 電源電流:1 mA 最大工作溫度:+ 70 C 封裝 / 箱體:SOIC-8 Narrow 封裝:Tube |
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