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参数资料
| 型号： | MAX8555AEUB+T |
| 厂商： | Maxim Integrated |
| 文件页数： | 14/17页 |
| 文件大小： | 0K |
| 描述： | IC CNTRLR MOSFET ORING 10-UMAX |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| 应用： | 电信电源，整流器 |
| FET 型： | N 沟道 |
| 输出数： | 1 |
| 内部开关： | 无 |
| 延迟时间 - 关闭： | 100ns |
| 电源电压： | 8 V ~ 13.25 V |
| 电流 - 电源： | 2mA |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 10-TFSOP，10-MSOP（0.118"，3.00mm 宽） |
| 供应商设备封装： | 10-µMAX |
| 包装： | 带卷 (TR) |
Low-Cost, High-Reliability, 0.5V to 3.3V ORing
MOSFET Controllers
UV ? 1
? ( V ? 0 . 8 ) ? ?
? 12 , 500 ? ?
?
?
? ? ? R TIMER ? ?
? ?
? ?
? ?
OV ? 1
R 5 = R 6 × ? OV ? 1 ?
Set the UVP Fault Threshold
Use a resistor-divider from the input supply to GND with
the center tap connected to UVP to set the undervoltage
threshold. Use a 10k ? resistor from UVP to GND (R4 in
Figure 4) and calculate R3 as follows:
? V ?
R 3 = R 4 ? ?
? V UVP ?
where V UV is the desired undervoltage trip point and
V UVP is the UVP reference threshold (0.4V typ). Connect
UVP to VL to disable the undervoltage-protection feature.
Set the OVP Fault Threshold
For a single-supply application, use a resistor-divider
from the output bus to GND with the center tap con-
nected to OVP to set the overvoltage threshold. Use a
10k ? resistor from OVP to GND (R6 in Figure 4) and
calculate R5 as follows:
? V ?
R 5 = R 6 ? ?
? V OVP ?
where V OV is the desired overvoltage threshold and V OVP
is the OVP reference threshold (0.5V typ). Connect OVP
to GND to disable the overvoltage-protection feature.
For (n + 1) applications, the required circuit values are:
R 6 = 1 k ?
? V ?
? V OVP ?
R 2 A = 47 k ?
R 2 B = 2 × R 5
where the resistors are as shown in Figure 2.
MOSFET Selection
The MAX8555/MAX8555A drive N-channel MOSFETs.
The most important specification of the MOSFETs is
R DS(ON) . As load current flows through the external
MOSFET, V DS is generated from source to drain due to
the MOSFET’s on-resistance, R DS(ON) . The MAX8555/
MAX8555A monitor V DS of the MOSFETs at all times to
determine the state of the monitored power supply.
Selecting a MOSFET with a low R DS(ON) allows more
current to flow through the MOSFETs before the
MAX8555/MAX8555A detect reverse-current (I REVERSE )
and forward-current (I FORWARD ) conditions.
Using Two MOSFETs
Two MOSFETs must be used for overvoltage protec-
tion. When using two external MOSFETs, the monitored
voltage equation becomes:
V DSTOTAL = R DS(ON)1 x I LOAD + R DS(ON)2 x I LOAD
Using One MOSFET
A single MOSFET can be used if the overvoltage-protec-
tion function is not needed. Connect CS+ to the source of
the MOSFET and CS- to the drain of the MOSFET.
Calculating GATE Current
The charge-pump output current is proportional to both
oscillator frequency and V VL . There is also a small inter-
nal load of approximately 6M ? . The GATE current for a
given V VL and R TIMER is calculated as:
? ?
I GATE ≈ ? 24 . 12 × ? L ? × ? 1 ? ? ? ? ? 0 . 4 ? μ A
3 . 4
Layout Guidelines
It is important to keep all traces as short as possible
and to maximize the high-current trace dimensions to
reduce the effect of undesirable parasitic inductance.
The MOSFET dissipates a fair amount of heat due to
the high currents involved, especially during an over-
current condition. To dissipate the heat generated by
the MOSFET, make the power traces very wide with a
large amount of copper area and place the MAX8555
as close as possible to the drain of the external MOS-
FET. A more efficient way to achieve good power dissi-
pation on a surface-mount package is to lay out two
copper pads directly under the MOSFET package on
both sides of the board. Use enlarged copper mount-
ing pads on the top side of the board. Use a ground
plane to minimize impedance and inductance. In addi-
tion to the usual high-power considerations, here are
three tips to prevent false faults:
1) Kelvin connect CS+ and CS- to the external
MOSFET and route the two traces in parallel, as
close as possible, back to the IC.
2) Bypass V DD with a 0.01μF capacitor to ground and
bypass CS+ and CS- with a 1000pF capacitor to
ground.
3) Make the traces connected to UVP and OVP as
short as possible.
Refer to the MAX8555/MAX8555A evaluation kit for an
example of good PC board layout.
14
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX8555AEVKIT | 功能描述:电源管理IC开发工具 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 |
| MAX8555ETB+ | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
| MAX8555ETB+T | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
| MAX8555ETB-T | 功能描述:功率驱动器IC RoHS:否 制造商:Micrel 产品:MOSFET Gate Drivers 类型:Low Cost High or Low Side MOSFET Driver 上升时间: 下降时间: 电源电压-最大:30 V 电源电压-最小:2.75 V 电源电流: 最大功率耗散: 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Tube |
| MAX8555EUB | 功能描述:功率驱动器IC RoHS:否 制造商:Micrel 产品:MOSFET Gate Drivers 类型:Low Cost High or Low Side MOSFET Driver 上升时间: 下降时间: 电源电压-最大:30 V 电源电压-最小:2.75 V 电源电流: 最大功率耗散: 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Tube |
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