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| 型号： | MC34652EFR2 |
| 厂商： | Freescale Semiconductor |
| 文件页数： | 16/26页 |
| 文件大小： | 1802K |
| 描述： | IC CTRLR HOT SWAP NEG V 16-SOIC |
| 标准包装： | 2,500 |
| 类型： | 热交换开关 |
| 应用： | 通用 |
| 内部开关： | 是 |
| 电流限制： | 2A |
| 电源电压： | 15 V ~ 80 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 16-SOIC（0.154"，3.90mm 宽） |
| 供应商设备封装： | 16-SOIC N |
| 包装： | 带卷 (TR) |
Analog Integrated Circuit Device Data
16
Freescale Semiconductor
34652
FUNCTIONAL DEVICE OPERATION
PROTECTION FEATURES
rchived by Freescale Semiconductor, Inc., 2008
Figure 15
shows how the 34652 uses the start-up timer to
make sure that the input voltage is above the undervoltage
falling threshold. The 34652 was in normal operation before
Point A. At Point A an undervoltage fault occurs. Then the
fault is cleared at Point B, and the 34652 initiates a start-up
sequence. Before the end of the start-up timer another
undervoltage fault occurs at Point C, so the 34652 does not
turn on the Power MOSFET. At Point D the fault is cleared
again for the length of the start-up timer. The 34652 turns on
the Power MOSFET and starts the charging process (refer to
Charging Process
, pages 1213).
Figure 15. Start-Up Timer Protection Against
Undervoltage Faults
OVERVOLTAGE
When the voltage on the OV pin exceeds the overvoltage
rising threshold for more than 1.0 ms, an overvoltage fault is
detected and one of the start-up conditions (list on page
12
)
is violated. The 34652 turns off the Power MOSFET and
deactivates the power good output signals, thus disabling the
load. The 34652 stays in this state until the voltage on the OV
pin falls below the overvoltage falling threshold for more than
1.0 ms, signaling that the supply voltage is in the normal
operation range. Then a new start-up sequence initiates as
described on page
12
.
The overvoltage detection circuit is also equipped with a
2.0 V hysteresis when in default mode. The hysteresis value
depends on the overvoltage detection threshold and can be
calculated as follows:
V
OVHY
= V
OV (RISING)
*
[1 - (1.3 V - V
OVCHY
) / 1.3 V ]
The waveforms for an overvoltage fault are shown in
Figure 16
, page 16
.
Figure 16. Overvoltage Fault
THERMAL SHUTDOWN
The thermal shutdown feature helps protect the internal
Power MOSFET and circuitry from excessive temperatures.
During start-up and thereafter during normal operation, the
34652 monitors the temperature of the internal circuitry for
excessive heat. If the temperature of the device exceeds the
thermal shutdown temperature of 160癈, one of the start-up
conditions (list on page
12
) is violated, and the device turns
off the Power MOSFET and deactivates the power good
output signals. Until the temperature of the device goes
below 135癈, a new start-up sequence will not be initiated.
This feature is an advantage over solutions with an external
Power MOSFET, because it is not easy for a device with an
external MOSFET to sense the temperature quickly and
accurately. The thermal shutdown circuit is equipped with a
12 約 filter.
Thermal design is critical to proper operation of the 34652.
The typical R
DS(ON)
of the internal Power MOSFET is
0.144 ?at room ambient temperature and can reach up to
0.251 ?at high temperatures. The thermal performance of
the 34652 can vary depending on many factors, among them:
" The ambient operating temperature (T
A
).
" The type of PC boardwhether it is single layer or multi-
layer, has heat sinks or not, etc.all of which affects the
value of the junction-to-ambient thermal resistance (R
窲A
).
" The value of the desired load current (I
LOAD
).
When choosing an overcurrent limit, certain guidelines
need to be followed to make sure that if the load current is
running close to the overcurrent limit the 34652 does not go
into thermal shutdown. It is good practice to set the
parameters so that the resulting maximum junction
temperature is below the thermal shutdown temperature by a
safe margin.
Equation 1, on the following page can be used to calculate
the maximum allowable overcurrent limit based on the
maximum desired junction temperature or vice versa.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MC34653 | 制造商:SPC Multicomp 功能描述:HEADER R/A SQ PIN 2.54MM 10WAY 制造商:SPC Multicomp 功能描述:HEADER, R/A, SQ PIN, 2.54MM, 10WAY 制造商:SPC Multicomp 功能描述:WIRE-BOARD CONN, HEADER, 10POS, 2.54MM; Connector Type:Wire to Board; Series:2217; Contact Termination:Through Hole Right Angle; Gender:Header; No. of Contacts:10; No. of Rows:1; Pitch Spacing:2.54mm; Contact Plating:Tin ;RoHS Compliant: Yes |
| MC34653EF | 功能描述:热插拔功率分布 1A 8-LD NVHS RoHS:否 制造商:Texas Instruments 产品:Controllers & Switches 电流限制: 电源电压-最大:7 V 电源电压-最小:- 0.3 V 工作温度范围: 功率耗散: 安装风格:SMD/SMT 封装 / 箱体:MSOP-8 封装:Tube |
| MC34653EFR2 | 功能描述:热插拔功率分布 1A 8-LD NVHS RoHS:否 制造商:Texas Instruments 产品:Controllers & Switches 电流限制: 电源电压-最大:7 V 电源电压-最小:- 0.3 V 工作温度范围: 功率耗散: 安装风格:SMD/SMT 封装 / 箱体:MSOP-8 封装:Tube |
| MC34655 | 制造商:SPC Multicomp 功能描述:HEADER SQUARE PIN 2.54MM 5WAY 制造商:SPC Multicomp 功能描述:HEADER, SQUARE PIN, 2.54MM, 5WAY 制造商:SPC Multicomp 功能描述:WIRE-BOARD CONNECTOR HEADER 5POS, 2.54MM; Connector Type:Wire to Board; Series:2217; Contact Termination:Through Hole Vertical; Gender:Header; No. of Contacts:5; No. of Rows:1; Pitch Spacing:2.54mm; Contact Plating:Tin ;RoHS Compliant: Yes |
| MC34657 | 制造商:SPC Multicomp 功能描述:HEADER VERTICAL 2WAY 制造商:SPC Multicomp 功能描述:HEADER, VERTICAL, 2WAY 制造商:SPC Multicomp 功能描述:WIRE-BOARD CONNECTOR, RCPT, 2POS, 4.2MM; Series:2266(5566)S; Pitch Spacing:4.2mm; Contact Termination:Through Hole Vertical; No. of Contacts:2; No. of Rows:2; Connector Mounting:PCB; Gender:Receptacle; Contact Material:Copper Alloy ;RoHS Compliant: Yes |
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