参数资料
| 型号： | MAX1801EKA+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 14/16页 |
| 文件大小： | 0K |
| 描述： | IC CNTRLR DC-DC SOT23-8 |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| 应用： | 控制器，数字式相机 |
| 输入电压： | 2.7 V ~ 5.5 V |
| 输出数： | 1 |
| 工作温度： | 0°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | SOT-23-8 |
| 供应商设备封装： | SOT-23-8 |
| 包装： | 带卷 (TR) |
Digital Camera Step-Up Slave
DC-DC Controller
step-down converter is suitable; use a step-up/step-
INPUT
1 CELL
Li+
MAIN
L 2
OUTPUT
down converter instead. One type of step-up/step-
down converter is the SEPIC shown in Figure 6.
Inductors L1 and L2 can be separate inductors or can
be wound on a single core and coupled as with a trans-
former. Typically, using a coupled inductor improves
efficiency because some power is transferred through
the coupling so that less power passes through the cou-
ON
DCON
EXT
C 2
Q 1
D 1
3.3V
pling capacitor, C2. Likewise, C2 should be a low-ESR-
type capacitor to improve efficiency. The coupling
MAX1801
COMP
FB
R 1
R 2
capacitor ripple current rating must be greater than the
larger of the input and output currents. The MOSFET
(Q1) drain-source voltage rating and the rectifier (D1)
reverse voltage rating must exceed the sum of the input
and output voltages. Other types of step-up/step-down
R C
G C
Figure 6. MAX1801 Auxiliary Controller, SEPIC Configuration
circuits are a flyback converter and a step-up converter
followed by a linear regulator.
Using the MAX1801 Controller for a
Multi-Output Flyback Circuit
Some applications require multiple voltages from a sin-
gle converter that features a flyback transformer.
Figure 7 shows a MAX1801 auxiliary controller in a two-
output flyback configuration. The controller drives an
external MOSFET that switches the transformer primary,
INPUT
D 3
+ OUTPUT
and the two secondaries generate the outputs. Only a
single positive output voltage can be regulated using
the feedback resistive voltage-divider, so the other volt-
ages are set by the turns ratio of the transformer secon-
daries. The regulation of the other secondary voltages
MAIN
ON
DCON
EXT
Q 1
D 2
- OUTPUT
degrades due to transformer leakage inductance and
winding resistance. Voltage regulation is best when the
load current is limited to a small range. Consult the
transformer manufacturer for the proper design for a
given application.
R 1
Using a Charge Pump to Make
MAX1801
COMP
FB
R 2
Negative Output Voltages
Negative output voltages can be produced without a
transformer using a charge-pump circuit with an auxil-
iary controller, as shown in Figure 8. When MOSFET Q1
R C
G C
Figure 7. MAX1801 Auxiliary Controller, Flyback Configuration
Using the MAX1801 Controller in
SEPIC Configuration
In cases where the battery voltage is above or below
the required output voltage, neither a step-up nor a
turns off, the voltage at its drain rises to supply current
to V OUT +. At the same time, C1 charges to the voltage
at V OUT + through D1. When the MOSFET turns on, C1
discharges through D3, thereby charging C3 to V OUT -
minus the drop across D3, to create roughly the same
voltage as V OUT + at V OUT - but with inverted polarity. If
different magnitudes are required for the positive and
negative voltages, a linear regulator can be used at one
of the outputs to achieve the desired voltages, while the
MAX1801 regulates the higher magnitude voltage.
14
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1802EHJ | 功能描述:直流/直流开关转换器 Step-Up Slave DC/DC Controller 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 |
| MAX1802EHJ+ | 功能描述:直流/直流开关转换器 Step-Up Slave DC/DC Controller 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 |
| MAX1802EHJ+T | 功能描述:直流/直流开关转换器 Step-Up Slave DC/DC Controller 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 |
| MAX1802EHJ-T | 功能描述:直流/直流开关转换器 Step-Up Slave DC/DC Controller 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 |
| MAX1804EUB | 功能描述:电流和电力监控器、调节器 RoHS:否 制造商:STMicroelectronics 产品:Current Regulators 电源电压-最大:48 V 电源电压-最小:5.5 V 工作温度范围:- 40 C to + 150 C 安装风格:SMD/SMT 封装 / 箱体:HPSO-8 封装:Reel |
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