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參數(shù)資料
| 型號： | MAX848 |
| 廠商： | Maxim Integrated Products, Inc. |
| 元件分類： | DC/DC變換器 |
| 英文描述： | Low-Noise, Step-Up DC-DC Converters(高功率，低噪，帶0.5AMOSFET功率開關,步升DC-DC變換器) |
| 中文描述： | 1至3節(jié)電池、大功率、低噪聲、升壓型DC-DC轉換器 |
| 文件頁數(shù)： | 14/16頁 |
| 文件大?。?/td> | 192K |
| 代理商： | MAX848 |
M
1-Cell to 3-Cell, High-Power,
Low-Noise, S tep-Up DC-DC Converters
14
______________________________________________________________________________________
Power-On Reset Delay
Adding a timing capacitor from POK to GND generates
a power-on reset delay. The reset time constant is
determined by the pull-up resistor and timing capacitor
(Figure 11). When power is turned on, POK is low and
the capacitor is shorted. When the output voltage
reaches regulation, POK goes high and the capacitor
slowly charges to the output voltage.
The timing resistor value depends on the controller’s
RESET input leakage current. The voltage drop across
the timing resistor should not exceed the difference
between the output voltage and the μC reset threshold
voltage. This resistor should be large enough to mini-
mize the shutdown current.
μC-Controlled S hutdown
The MAX848/MAX849 turn on when ON1 = 1 or
ON2
= 0.
The μC monitors the battery voltage and turns off the
device (forces ON1 low and
ON2
high) when the bat-
tery is weak.
Layout Considerations
Due to high inductor current levels and fast switching
waveforms, which radiate noise, proper PC board lay-
out is essential. Protect sensitive analog grounds by
using a star ground configuration. Minimize ground
noise by connecting PGND, the input bypass capacitor
ground lead, and the output filter capacitor ground lead
to a single point (star ground configuration). Also, mini-
mize lead lengths to reduce stray capacitance and
trace resistance.
If an external resistor divider is used to set the output
voltage (Figure 5), the trace from FB to the resistors
must be extremely short and must be shielded from
switching signals, such as CLK, DATA, or LX.
MAX848
MAX849
OUT
POK
V
CC
RESET
μ
C
R
C
Figure 11. Power-On Reset Delay
Table 4. Component Selection Guide
PRODUCTION
INDUCTORS
CAPACITORS
DIODES
Surface Mount
Sumida CDR63B, CD73, CDR73B, CD74B series
Coilcraft DO1608, DO3308, DT3316 series
Matsuo 267 series
Sprague 595D series
AVX TPS series
Motorola MBR0520L
Through Hole
Sumida RCH654 series
Sanyo OS-CON series
Nichicon PL series
Motorola 1N5817
Table 5. Component Suppliers
SUPPLIER
PHONE
FAX
AVX
USA: (803) 946-0690
(800) 282-4975
(803) 626-3123
Coilcraft
Matsuo
Motorola
USA: (847) 639-6400
USA: (714) 969-2491
USA: (602) 303-5454
(847) 639-1469
(714) 960-6492
(602) 994-6430
Sanyo
USA: (619) 661-6835
J apan: 81-7-2070-6306
(619) 661-1055
81-7-2070-1174
Sumida
USA: (847) 956-0666
J apan: 81-3-3607-5111
(847) 956-0702
81-3-3607-5144
___________________Chip Information
TRANSISTOR COUNT: 2059
相關PDF資料 |
PDF描述 |
|---|---|
| MAX849 | Low-Noise, Step-Up DC-DC Converters(高功率，低噪，帶0.5AMOSFET功率開關,步升DC-DC變換器) |
| MAX8530 | Dual Low-Dropout Linear Regulators with RESETor Low-Noise Output in UCSP or QFN |
| MAX8530EBT | Dual Low-Dropout Linear Regulators with RESETor Low-Noise Output in UCSP or QFN |
| MAX8530ETT | Dual Low-Dropout Linear Regulators with RESETor Low-Noise Output in UCSP or QFN |
| MAX8531 | Dual Low-Dropout Linear Regulators with RESETor Low-Noise Output in UCSP or QFN |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| MAX848ESE | 功能描述:直流/直流開關轉換器 1-3 Cell Step-Up DC/DC Converter RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關頻率: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 安裝風格:SMD/SMT |
| MAX848ESE+ | 功能描述:直流/直流開關轉換器 1-3 Cell Step-Up DC/DC Converter RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關頻率: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 安裝風格:SMD/SMT |
| MAX848ESE+T | 功能描述:直流/直流開關轉換器 1-3 Cell Step-Up DC/DC Converter RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關頻率: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 安裝風格:SMD/SMT |
| MAX848ESE-T | 功能描述:直流/直流開關轉換器 1-3 Cell Step-Up DC/DC Converter RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關頻率: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 安裝風格:SMD/SMT |
| MAX849ESE | 功能描述:直流/直流開關轉換器 1-3 Cell Step-Up DC/DC Converter RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關頻率: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 安裝風格:SMD/SMT |
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