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參數(shù)資料
| 型號： | SP6643 |
| 元件分類： | DC/DC變換器 |
| 英文描述： | Single Alkaline Cell, High Efficiency Step-Up DC-DC Converter(單堿性電池，3.3V或可調(diào)電壓,高效步升DC-DC變換器) |
| 中文描述： | 單節(jié)堿性，高效率步細(xì)胞型DC - DC轉(zhuǎn)換器（單堿性電池，3.3伏或可調(diào)電壓，高效步升的DC - DC變換器） |
| 文件頁數(shù)： | 13/16頁 |
| 文件大?。?/td> | 248K |
| 代理商： | SP6643 |
Rev. 10-6-00
SP6642/6643 High Efficiency Step-Up DC-DC Converter Copyright 2000 Sipex Corporation
13
synchronous-rectifier body diode from the input
to the output. To disable the shutdown feature,
designers can connect SHDN to V
BATT
.
Adjustable Output Voltage
Driving FB to ground (logic LOW) will drive
the output voltage to the fixed-voltage operation
of +3.3V + 4%. Connecting FB to a voltage
divider between V
and ground will select an
adjustable output voltage between +2V and
+5.5V. Refer to
Figure 25
. FB regulates to
+1.23V.
Since the FB leakage current is 10nA maximum,
designers should select the feedback resistor R2
in the 100k
to 1M
range. R1 can be
determined with the following equation:
R1 = R2 x V
OUT
V
REF
where R3 and R4 are the feedback resistors in
Figure 25
, V
OUT
is the output voltage, and V
REF
is 1.23V.
Battery Reversal Protection
The SP6642/6643 devices will tolerate single-
cell battery reversal up to the package power-
dissipation limits noted in the
ABSOLUTE
MAXIMUM RATINGS
section. An internal
GND
V
OUT
0.1
μ
F
FB
LX
V
BATT
22
μ
F
0.1
μ
F
22
μ
F
PFI
V
=
2V to 5.2V
SHDN
100
μ
H
350mA
0.88V to
1.65V Input
SP6642
PFO
100pF*
R1
R2
*optional compensation
Figure 25. Adjustable Output Voltage Circuitry
diode in series with an internal 5
resistor limits
any reverse current to less than 220mA
preventing damage to the devices. Prolonged
operation above 220mA reverse-battery current
can degrade performance of the devices.
The Inductor
It is recommended that designers implement a
100
μ
H inductor for typical application of the
SP6642/6643 devices. Lower inductor values
down to 68
μ
H will increase the maximum
output current. Higher inductor values up to
220
μ
H will reduce peak inductor current and
any consequent ripple and noise. The saturation-
current rating of the inductor selected must
exceed the peak current limit synthesized by the
SP6642/6643 devices' timing algorithms. This
can be calculated with the following equation:
I
PEAK
=K
MAX
L
MIN
where I
PEAK
is the peak current, K
MAX
is 35V-
μ
s,
and L
The maximum recommended I
is 350mA.
To optimize efficiency, select an inductor with
a series resistance less than 1
.
Table 1
lists surface mount inductor information
for the user, including series resistance and
saturation current rating.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| SP6644 | Evaluation Board Manual |
| SP6645UEB | Evaluation Board Manual |
| SP6644EB | Evaluation Board Manual |
| SP6644EU | Single/Dual Alkaline Cell, High Efficiency Step-Up DC-DC Converter |
| SP6645 | Single/Dual Alkaline Cell, High Efficiency Boost DC-DC Regulator |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| SP6643EU | 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:Application Note:High Current Output |
| SP6644 | 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:Single/Dual Alkaline Cell, High Efficiency Step-Up DC-DC Converter |
| SP6644_05 | 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:Single/Dual Alkaline Cell, High Efficiency Boost DC-DC Regulator |
| SP6644EB | 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:Evaluation Board Manual |
| SP6644EU | 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:Single/Dual Alkaline Cell, High Efficiency Boost DC-DC Regulator |
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