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參數(shù)資料
| 型號(hào)： | MAX1677EEE |
| 廠商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | Compact, High-Efficiency, Dual-Output Step-Up and LCD Bias DC-DC Converter |
| 中文描述： | 0.8 A SWITCHING REGULATOR, 360 kHz SWITCHING FREQ-MAX, PDSO16 |
| 封裝： | 0.150 INCH, 0.025 INCH PITCH, QSOP-16 |
| 文件頁(yè)數(shù)： | 12/16頁(yè) |
| 文件大?。?/td> | 201K |
| 代理商： | MAX1677EEE |
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S hutdown: ON and LCDON
A logic-low level at ON shuts down all MAX1677 cir-
cuits including the LCD converter, reference, and LBI
comparator. A logic-high level at LCDON activates the
LCD boost converter. The LCD boost converter can
only be activated when ON is high. When ON is low,
the MAX1677 draws 1μA.
Low-Battery Comparator
The MAX1677 has an on-chip comparator for low-bat-
tery detection. If the voltage at LBI falls below 614mV,
LBO
(an open-drain output) sinks current to GND. The
low-battery trip level is set by two resistors (Figure 6).
Since the LBI input current is less than 50nA, large
resistor values (R6
≤
130k
) can be used to minimize
input loading. Calculate R5 as follows:
R5 = R6 [(V
TRIP
/ 0.614V) – 1]
Connect a pull-up resistor (R8) to
LBO
when driving
CMOS logic.
LBO
is an open-drain output and can be
pulled as high as 6V regardless of the voltage at OUT.
When LBI is above 0.614V,
LBO
is high impedance. If
the LBI comparator is not used, ground LBI.
Since the low-battery comparator is noninverting, hys-
teresis can be added by connecting a resistor (R7)
from LBI to
LBO
as shown in Figure 7. When
LBO
is
high, the series combination of R8 and R7 source cur-
rent into the summing node at LBI (no current flows into
the IC).
Design Proc edure
The MBC feedback pin (FB) features Dual Mode opera-
tion. With FB grounded, the MBC output is preset to
3.3V. It can also be adjusted from 2.5V to 5.5V with
external resistors, R3 and R4, as shown in Figure 8. To
set the output voltage externally, select resistor R4 in
the 10k
to 200k
range. Calculate R3 using:
R3 = R4 [(V
OUT
/ 1.25V) – 1]
S etting the LCD Output V oltage
For either positive or negative LCD output voltages, set
the voltage with two external resistors, R1 and R2, as
shown in Figures 2 and 3. Since the input current at FB
has a maximum of 50nA, large resistors can be used
without significant accuracy loss. Begin by selecting R2
in the 10k
to 200k
range and calculate R1 using one
of the following two equations (for positive or negative
output).
MAX1677
POUT
LBO
LOGIC POWER
LOW-BATTERY OUTPUT
LBI
V
IN
(V
TRIP
)
R5
R6
R8
Figure 6. Setting the Low-Battery Trip Threshold
MAX1677
POUT
LBO
LBI
V
IN
(V
TRIP
: V
H
, V
L
)
R5
R6
R8
100k
R7
WHERE V
H
IS THE RISING V
TRIP
LEVEL
AND V
L
IS THE FALLING V
TRIP
LEVEL.
H
= 0.614V
[
1+ R5 + R5
]
V
L
= 0.614V
[
1+ R7 - (V
POUT
- 0.614V) (R7 + R8)
]
V
Figure 7. Adding External Hysteresis to the LBI Comparator
MAX1677
POUT
FB
MBC OUTPUT
R3
R4
GND
Figure 8. Setting the MBC Output Voltage Externally
M
Compac t, High-Effic ienc y, Dual-Output
S tep-Up and LCD Bias DC-DC Converter
12
______________________________________________________________________________________
Table 3. Setting LCD Output Polarity and
Peak Inductor Current
225
GND through 50k
Negative
225
OUT through 50k
Positive
350
350
L
CDLX
PEAK
INDUCTOR CURRENT
(mA)
LCDPOL
CONNECTED TO:
OUT
GND
Negative
Positive
LCD
OUTPUT
POLARITY
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MAX1677EEE+ | 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 Compact Step-Up & LCD Bias DC/DC RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT |
| MAX1677EEE+T | 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 Compact Step-Up & LCD Bias DC/DC RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT |
| MAX1677EEE-T | 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 Compact Step-Up & LCD Bias DC/DC RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT |
| MAX1677EVKIT | 功能描述:電源管理IC開發(fā)工具 Evaluation Kit for the MAX1677 RoHS:否 制造商:Maxim Integrated 產(chǎn)品:Evaluation Kits 類型:Battery Management 工具用于評(píng)估:MAX17710GB 輸入電壓: 輸出電壓:1.8 V |
| MAX1678ESA | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
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