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参数资料
| 型号： | MAX1802EHJ+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 17/28页 |
| 文件大小： | 0K |
| 描述： | IC PWR SPLY STEP DOWN 32-TQFP |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 360 |
| 应用： | 控制器，数字式相机 |
| 输入电压： | 2.5 V ~ 11 V |
| 输出数： | 5 |
| 输出电压： | 1.25 V ~ 5.5 V |
| 工作温度： | 0°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 32-TQFP |
| 供应商设备封装： | 32-TQFP（5x5） |
| 包装： | 托盘 |
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Digital Camera Step-Down
Power Supply
FB_
COMP_
REF
DCON_
OSC
Figure 3. Auxiliary Controller Block Diagram
LEVEL
SHIFT
SOFT-
START
CLK
R
S
FAULT
PROTECTION
Q
DL_
trollers regulate their output voltages by modulating the
pulse width of the drive signal for an external N-channel
MOSFET switch. The auxiliary controllers are inactive
until the main output has started.
Figure 3 shows a block diagram for a MAX1802 auxil-
iary PWM controller. The sawtooth oscillator signal at
OSC governs the internal timing. At the beginning of
each cycle, DL_ goes high to turn on the external MOS-
FET switch. The MOSFET switch turns off when the
internally level-shifted sawtooth rises above COMP_ or
when the maximum duty cycle is exceeded. The switch
remains off until the beginning of the next cycle. An
internal transconductance amplifier establishes an inte-
grated error voltage at COMP_, thereby increasing the
loop gain for improved regulation accuracy.
Power-Up Sequence
The MAX1802 is in the shutdown state with all circuitry
off when the ONM input is low (<1.3V). When ONM
goes high, an internal linear regulator generates 3V at
the VL output from the VDDM input to power internal
circuitry. As VL rises above the 2.4V undervoltage lock-
out threshold, the internal reference and oscillator
begin to function and the main DC-DC converter
begins soft-start operation. The main DC-DC output
reaches full regulation voltage after 1024 soft-start
oscillator cycles. Once the main DC-DC converter com-
pletes soft-start, the core DC-DC converter and the
auxiliary DC-DC controllers are enabled.
As the voltage at VDDC rises above 2.4V, the internal
linear regulator turns off and an internal 3 ? switch con-
nects VL directly to VDDC, which is typically connected
to the output of the main DC-DC converter.
The core DC-DC converter and the auxiliary DC-DC
controllers have independent on-off control and soft-
start. The main DC-DC converter shuts down with a low
input at ONM. The core DC-DC converter shuts down
with a low input at ONC. Turn auxiliary DC-DC convert-
er 1 off by driving either ON1 or DCON1 to GND. Turn
off auxiliary controller 2 or 3 by driving DCON2 or
DCON3 to GND.
Reference
The MAX1802 has an internal 1.248V, 1% reference.
Connect a 0.1μF bypass capacitor from REF to GND
within 0.2in (5mm) of the REF pin. REF can source up
to 200μA of external load current, and it is enabled
whenever ONM is high and VL is above the undervolt-
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| 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 |
| MAX1804EUB+ | 功能描述:电流和电力监控器、调节器 Feedback Integrator for Power Supply 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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