9
425112fd
LTC4251/LTC4251-1/
LTC4251-2
For more information www.linear.com/4251
OPERATION
Hot Circuit Insertion
When circuit boards are inserted into a live backplane, the
supply bypass capacitors can draw huge transient currents
from the power bus as they charge. The flow of current
damages the connector pins and glitches the power bus,
causing other boards in the system to reset. The LTC4251/
LTC4251-1/LTC4251-2 are designed to turn on a circuit
board supply in a controlled manner, allowing insertion or
removal without glitches or connector damage.
Initial Start-Up
The LTC4251/LTC4251-1/LTC4251-2 reside on a removable
circuit board and control the path between the connector
and load or power conversion circuitry with an external
MOSFET switch (see Figure 1). Both inrush control and
short-circuit protection are provided by the MOSFET .
A detailed schematic is shown in Figure 2. 48V and
48RTN receive power through the longest connector pins,
and are the first to connect when the board is inserted.
The GATE pin holds the MOSFET off during this time. UV/
OV determines whether or not the MOSFET should be
turned on based upon internal, high accuracy thresholds
and an external divider. UV/OV does double duty by also
monitoring whether or not the connector is seated. The top
of the divider detects 48RTN by way of a short connector
pin that is the last to mate during the insertion sequence.
Interlock Conditions
A start-up sequence commences once five initial interlock
conditions are met:
1. The input voltage V
IN
exceeds 9.2V (V
LKO
)
2. The voltage at UV/OV falls within the range of V
UVHI
to
V
OVLO
(UV > V
UVHI
, LTC4251-2)
3. The (SENSE V
EE
) voltage is <50mV (V
CB
)
4. The voltage on the timer capacitor (C
T
) is less than 1V
(V
TMRL
)
5. GATE is less than 0.5V (V
GATEL
)
The first two conditions are continuously monitored and
the latter three are checked prior to initial timing or GATE
ramp-up. Upon exiting an OV condition, the TIMER pin
voltage requirement is inhibited. Details are described in
the Applications Information, Timing Waveforms section.
TIMER begins the start-up sequence by sourcing 5.8礎
into C
T
. If V
IN
or UV/OV falls out of range, the start-up
cycle stops and TIMER discharges C
T
to less than 1V ,
then waits until the aforementioned conditions are once
again met. If C
T
successfully charges to 4V , TIMER pulls
low and GATE is released. GATE sources 58礎 (I
GATE
),
charging the MOSFET gate and associated capacitance.
Note that for simplicity, the following assumptions are made in the text. Firstly, UV/OV also means the UV
pin of the LTC4251-2. Secondly, all overvoltage conditions and references to OV, V
OVHI
and V
OVLO
do not apply to the LTC4251-2 as the
OV comparator in this part is disabled.
425112 F01
LTC4251
C
LOAD
ISOLATED
DC/DC
CONVERTER
MODULE
LOW
VOLTAGE
CIRCUITRY
+
+
PLUG-IN BOARD
BACKPLANE
48RTN
48V
+
3
4
1
2
425112 F02
48RTN
48V
UV/OV
TIMER
V
EE
V
IN
SENSE GATE
LTC4251
R1
402k
1%
R2
32.4k
1%
C
T
150nF
C
C
18nF
R
S
20m
Q1
IRF530S
R
C
10
R
IN
10k
500mW
C1
10nF
C
IN
1礔
D
IN
DDZ13B**
C
L
100礔
TYP
LONG
LONG
SHORT
**DIODES, INC.
RECOMMENDED FOR HARSH ENVIRONMENTS
+
Figure 1. Basic LTC4251 Hot Swap Topology
Figure 2. 48V, 2.5A Hot Swap Controller
发布紧急采购，3分钟左右您将得到回复。
相关PDF资料
LTC4252A-1IMS#TRPBF
IC CNTRLR HOTSWAP NEGVOLT 10MSOP
LTC4253ACGN#TRPBF
IC HOT SWAP CONTRLR -48V 16-SSOP
LTC4257CS8
IC CTRLR INTFACE PWR/ETHER 8SOIC
LTC4260IUH#PBF
IC HOT SWAP CNTRL I2C 32-QFN
LTC4261IGN-2#PBF
IC CTRLR HOTSWAP W/ADC 28-SSOP
LTC4263IS#TRPBF
IC IEEE 803.2AF CNTRLR 14-SOIC
LTC4268IDKD-1#PBF
IC PD HIGH POWER W/CNTRL 32-DFN
LTC4274CUHF#PBF
IC CONTROLLER POE 38-QFN
相关代理商/技术参数
LTC4251-2IS6
制造商:LINER 制造商全称:Linear Technology 功能描述:Negative Voltage Hot Swap Controllers in SOT-23
LTC4251-2IS6#TR
功能描述:IC CTRLR HOTSWP NEG VOLT SOT23-6 RoHS:否 类别:集成电路 (IC) >> PMIC - 热交换 系列:- 标准包装:50 系列:- 类型:热交换控制器 应用:-48V 远程电力系统，AdvancedTCA ? 系统，高可用性 内部开关:无 电流限制:可调 电源电压:11.5 V ~ 14.5 V 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-MSOP 包装:管件
LTC4251-2IS6#TRM
功能描述:IC CTRLR HOTSWP NEG VOLT SOT23-6 RoHS:否 类别:集成电路 (IC) >> PMIC - 热交换 系列:- 标准包装:50 系列:- 类型:热交换控制器 应用:-48V 远程电力系统，AdvancedTCA ? 系统，高可用性 内部开关:无 电流限制:可调 电源电压:11.5 V ~ 14.5 V 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-MSOP 包装:管件
LTC4251-2IS6#TRMPBF
功能描述:IC CTRLR HOTSWAP NEGVOLT SOT23-6 RoHS:是 类别:集成电路 (IC) >> PMIC - 热交换 系列:- 标准包装:50 系列:- 类型:热交换控制器 应用:-48V 远程电力系统，AdvancedTCA ? 系统，高可用性 内部开关:无 电流限制:可调 电源电压:11.5 V ~ 14.5 V 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-MSOP 包装:管件
LTC4251-2IS6#TRPBF
功能描述:IC CTRLR HOTSWAP NEGVOLT SOT23-6 RoHS:是 类别:集成电路 (IC) >> PMIC - 热交换 系列:- 标准包装:50 系列:- 类型:热交换控制器 应用:-48V 远程电力系统，AdvancedTCA ? 系统，高可用性 内部开关:无 电流限制:可调 电源电压:11.5 V ~ 14.5 V 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-MSOP 包装:管件
LTC4251BCS6#TRMPBF
功能描述:IC HOT SWAP CONTROLLER 6SOT23 RoHS:是 类别:集成电路 (IC) >> PMIC - 热交换 系列:- 标准包装:50 系列:- 类型:热交换控制器 应用:-48V 远程电力系统，AdvancedTCA ? 系统，高可用性 内部开关:无 电流限制:可调 电源电压:11.5 V ~ 14.5 V 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-MSOP 包装:管件
LTC4251BCS6#TRMPBF
制造商:Linear Technology 功能描述:HOT SWAP CONTROLLER -48V SOT23-6
LTC4251BCS6#TRPBF
功能描述:IC HOT SWAP CONTROLLER 6SOT23 RoHS:是 类别:集成电路 (IC) >> PMIC - 热交换 系列:- 标准包装:50 系列:- 类型:热交换控制器 应用:-48V 远程电力系统，AdvancedTCA ? 系统，高可用性 内部开关:无 电流限制:可调 电源电压:11.5 V ~ 14.5 V 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-MSOP 包装:管件
