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参数资料
| 型号： | MAX8569EVKIT+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 8/11页 |
| 文件大小： | 0K |
| 描述： | EVALUATION KIT FOR MAX8569 |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 1 |
| 主要目的： | DC/DC，步升 |
| 输出及类型： | 1，非隔离 |
| 电流 - 输出： | 200mA |
| 输入电压： | 1.5 ~ 5.5 V |
| 稳压器拓扑结构： | 升压 |
| 板类型： | 完全填充 |
| 已供物品： | 板 |
| 已用 IC / 零件： | MAX8569 |
200mA Step-Up Converters in 6-Pin
SOT23 and TDFN
Low-Battery Cutoff
The SHDN trip threshold of the MAX8569A/MAX8569B
can be used as an input voltage detector that disables
the IC when the battery voltage falls to a set level. The
SHDN trip threshold is 1.228V. Use a resistor-divider to
set the battery-detection voltage (R1 and R2 in Figure 1).
Select R2 between 100k ? and 1M ? to minimize battery
drain. Calculate R1 as follows:
R1 = R2 x ((V OFF / V SHDN ) - 1)
where V OFF is the battery voltage at which the part
shuts down and V SHDN = 1.228V. Note that input ripple
can sometimes cause false shutdowns. To minimize the
effect of ripple, connect a low-value capacitor (C2)
from SHDN to GND to filter out input noise. Select a C2
value so the R1, C2 time constant is above 2ms.
Power-On Reset ( RST, MAX8569B)
The MAX8569B provides a power-on reset output ( RST )
that goes high impedance when the output reaches 90%
of its regulation point. RST pulls low when the output is
below 90% of the regulation point. Connect a 100k ? to
1M ? pullup resistor from RST to OUT to provide a logic
control signal for a microprocessor. Connect RST to
GND when the reset function is not used.
Setting the Output Voltage (MAX8569A)
The output of the MAX8569A is adjustable from 2V to
5.5V. Connect a resistor-divider from the output to ground
with FB connected to the center tap to set the desired
output voltage (R3 and R4, Figure 1). Select R4 between
100k ? and 1M ? . R3 is then calculated as follows:
R3 = R4 x ((V OUT / V FB ) - 1)
where V OUT is the desired output voltage and V FB is
1.228V.
where R L is the inductor series resistance and R NCH is
the R DS(ON) of the internal n-channel MOSFET (0.3 ? typ).
Capacitor Selection
Choose an output capacitor to achieve the desired out-
put ripple percentage.
C OUT > (0.5 x L x 0.780A 2 ) / (r% x V OUT 2 )
where L is the inductor value and r is the desired output
ripple in %. A 22μF ceramic capacitor is a good start-
ing value.
The input capacitor reduces the peak current drawn
from the battery and can be the same value as the out-
put capacitor. A larger input capacitor can be used to
further reduce the input ripple and improve efficiency.
PC Board Layout and Grounding
Careful printed circuit layout is important for minimizing
ground bounce and noise. Keep the IC ’ s GND pin and
the ground leads of the input- and output-filter capaci-
tors less than 0.2in (5mm) apart. In addition, keep all
connections to the FB and LX pins as short as possible.
In particular, when using external feedback resistors,
locate them as close to FB as possible. To maximize
output power and efficiency and minimize output ripple
voltage, use a ground plane and solder the IC ’ s GND
directly to the ground plane. A sample layout is avail-
able in the MAX8569A/MAX8569B evaluation kit to
speed designs.
Chip Information
PROCESS: BiCMOS
Selector Guide
Inductor Selection
The control scheme of the MAX8569A/MAX8569B per-
mits flexibility in choosing an inductor. A 10μH inductor
performs well for most applications, but values from
4.7μH to 100μH can be used as well. Small inductance
values typically offer smaller physical size. Output
power is reduced when the inductance is large enough
to prevent the maximum current limit (780mA) from
PART
MAX8569AEUT
MAX8569BEUT
MAX8569AETT
MAX8569BETT
MAX8569BETT30
OUTPUT
VOLTAGE
Adjustable
Fixed 3.3V
Adjustable
Fixed 3.3V
Fixed 3.0V
PIN-
PACKAGE
SOT23-6
SOT23-6
TDFN
TDFN
TDFN
TOP
MARK
ABWK
ABWL
AJN
AJO
AJP
being reached before the maximum on-time (5μs)
expires. For maximum output current, choose L so that:
V BATT ( MAX ) × 1 μ s
0 . 78 A
< L <
V BATT ( MIN ) × 5 μ s
0 . 78 A
× ? V BATT ( MIN ) ? × ( R NCH + R L ) ?
I OUT ( MAX ) =
0 . 78 A
2
? 0 . 78 A ?
? 2 ?
V OUT
8
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相关代理商/技术参数 |
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| MAX8569EVKIT+ | 功能描述:电源管理IC开发工具 MAX8569 Eval Kit RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
| MAX856C/D | 功能描述:直流/直流开关转换器 DICE SALES DICE RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| MAX856C/D DIE | 制造商:Maxim Integrated Products 功能描述: |
| MAX856CPA | 功能描述:直流/直流开关转换器 RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| MAX856CSA | 功能描述:直流/直流开关转换器 3.3/5/AdjV Step-Up DC/DC Converter RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
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