参数资料
| 型号： | MAX4864LELT+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 9/11页 |
| 文件大小： | 0K |
| 描述： | IC CTLR OVP 7.4V 6-UDFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| 类型： | 过压保护控制器 |
| 应用： | 手机，数码相机，媒体播放器 |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 6-WDFN |
| 供应商设备封装： | 6-uDFN（2x2） |
| 包装： | 带卷 (TR) |
MAX4864L/MAX4865L/MAX4866L/MAX4867
Detailed Description
The MAX4864L/MAX4865L/MAX4866L/MAX4867 provide
up to +28V overvoltage and negative voltage protection
for low voltage systems. When the input voltage exceeds
the overvoltage trip level, the MAX4864L/MAX4865L/
MAX4866L/MAX4867 turn off a low-cost external n-channel
MOSFET to prevent damage to the protected compo-
nents. The devices also drive an external p-channel
MOSFET to protect against negative voltage inputs. An
internal charge-pump (see the
Functional Diagram),
drives the MOSFET GATEN for a simple, robust solution.
On power-up, the device waits for 50ms before driving
GATEN high. The open-drain FLAG output is kept at a
high impedance for an additional 50ms after GATEN goes
high before deasserting. The FLAG output asserts high
immediately to an overvoltage fault.
Undervoltage Lockout (UVLO)
The MAX4864L/MAX4865L/MAX4866L have a fixed
+2.85V typical UVLO level, and the MAX4867 has
+2.5V UVLO level. When VIN is less than the UVLO, the
GATEN driver is held low and FLAG is asserted.
Overvoltage Lockout (OVLO)
The MAX4864L has a +7.4V typical OVLO threshold;
the MAX4865L has +6.35V typical OVLO threshold; the
MAX4866L has a +5.8V typical OVLO threshold; and
the MAX4867 has a +4.65V typical OVLO threshold.
When VIN is greater than OVLO, the GATEN driver is
held low and FLAG is asserted.
FLAG Output
The open-drain FLAG output is used to signal to the
host system when there is a fault with the input voltage.
On power-up, FLAG is held high for 50ms after GATEN
turns on, before deasserting. FLAG asserts immediately
to overvoltage and undervoltage faults. When the fault
condition is removed, FLAG deasserts 50ms after
GATEN turns on. Connect a pullup resistor from FLAG
to the logic I/O voltage of the host system.
GATEN Driver
An on-chip charge pump is used to drive GATEN
above IN, allowing the use of a low-cost n-channel
MOSFET. The charge pump operates from the internal
+5.5V regulator.
The actual GATEN output voltage tracks approximately
two times VIN until VIN exceeds +5.5V, or the OVLO trip
level is exceeded, whichever comes first. The
MAX4864L has a +7.4V typical OVLO, therefore GATEN
remains relatively constant at approximately +10.5V for
+5.5V < VIN < +7.4V. The MAX4866L has a +5.8V typi-
cal OVLO, but this can be as low as +5.5V. The GATEN
output voltage is a function of input voltage, as shown
in the
Typical Operating Characteristics.
GATEP Driver
When the input voltage drops below ground, GATEP
goes high turning the external p-channel MOSFET off.
When the input voltage goes above ground, GATEP
pulls low and turns on the p-channel MOSFET. An inter-
nal clamp protects the p-channel MOSFET by insuring
that the GATEP-to-IN voltage does not exceed +16V
when the input (IN) rises to +28V.
Device Operation
The MAX4864L/MAX4865L/MAX4866L/MAX4867 have
an on-board state machine to control device operation.
A flowchart is shown in Figure 5. On initial power-up, if
VIN < UVLO or if VIN > OVLO, GATEN is held at 0V and
FLAG is high.
If UVLO < VIN < OVLO, the device enters startup after a
50ms internal delay. The internal charge pump is
enabled, and GATEN begins to be driven above VIN by
the internal charge pump. FLAG is held high during
startup until the FLAG blanking period expires, typically
50ms after the GATEN starts going high. At this point,
the device is in its on-state.
At any time if VIN drops below UVLO, FLAG is driven
high and GATEN is driven to ground.
STANDBY
GATEN = 0
FLAG = HIGH
TIMER STARTS
COUNTING
VIN > UVLO
VIN < UVLO
VIN > OVLO
OVLO CHECK
GATEN = 0
FLAG = HIGH
STARTUP
GATEN DRIVEN HIGH
FLAG = HIGH
ON
GATEN HIGH
FLAG = LOW
t = 50ms
Figure 5. State Diagram
Overvoltage Protection Controllers
with Reverse Polarity Protection
_______________________________________________________________________________________
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX4864LEUT | 制造商:Maxim Integrated Products 功能描述:OVERVOLTAGE PROTECTION CONTROLLERS - Rail/Tube 制造商:Rochester Electronics LLC 功能描述: |
| MAX4864LEUT+T | 功能描述:电源开关 IC - 配电 RoHS:否 制造商:Exar 输出端数量:1 开启电阻（最大值）:85 mOhms 开启时间（最大值）:400 us 关闭时间（最大值）:20 us 工作电源电压:3.2 V to 6.5 V 电源电流（最大值）: 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:SOT-23-5 |
| MAX4864LEUT-T | 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 |
| MAX4865ELT+ | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
| MAX4865ELT+T | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
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