参数资料
型号: LT4250HIN8
厂商: Linear Technology
文件页数: 11/14页
文件大小: 236K
描述: IC CONTRLR HOT SWAP NEG 48V 8DIP
标准包装: 50
类型: 热交换控制器
应用: 通用
内部开关:
电源电压: -20 V ~ -80 V
工作温度: -40°C ~ 85°C
安装类型: 通孔
封装/外壳: 8-DIP(0.300",7.62mm)
供应商设备封装: 8-PDIP
包装: 管件
LT4250L/LT4250H
11
4250lhfa
 APPLICATIONS INFORMATION
Undervoltage and Overvoltage Detection
The UV (Pin 3) and OV (Pin 2) pins can be used to detect
undervoltage and overvoltage conditions at the power sup-
ply input. The UV and OV pins are internally connected to
analog comparators with 130mV and 20mV of hysteresis
respectively. When the UV pin falls below its threshold or
the OV pin rises above its threshold, the GATE pin is im-
mediately pulled low. The GATE pin will be held low until
UV is high and OV is low.
The undervoltage and overvoltage trip voltages can be
programmed using a three resistor divider as shown in
Figure 11. With R4 = 549k, R5 = 6.49k and R6 = 10K, the
undervoltage threshold is set to 38.5V (with a 43V release
from undervoltage) and the overvoltage threshold is set
to 71V . The resistor divider will also gain up the hysteresis
at the UV pin and OV pin to 4.5V and 1.2V at the input
respectively.
PWRGD/PWRGD Output
The PWRGD/PWRGD output can be used to directly enable
a power module when the input voltage to the module is
within tolerance. The LT4250L has a PWRGD output for
modules with an active low enable input, and the LT4250H
has a PWRGD output for modules with an active high
enable input.
When the DRAIN voltage of the LT4250H is high with
respect to V
EE
 (Figure 12) or the GATE voltage is low, the
internal transistor Q3 is turned off and I
1
 and Q2 clamp
the PWRGD pin one SAT drop (H0.3V) above the DRAIN
pin.Transistor Q2 sinks the modules pull-up current and
the module turns off.
When the DRAIN voltage drops below V
DL
 and the GATE
voltage is high, Q3 will turn on, shorting the bottom of
I
1
 to DRAIN and turning Q2 off. The pull-up current in
the module pulls the PWRGD pin high and enables the
module.
When the DRAIN voltage of the LT4250L is high with
respect to V
EE
 or the GATE voltage is low, the internal
pull-down transistor Q2 is off and the PWRGD pin is in a
high impedance state (Figure 13). The PWRGD pin will be
pulled high by the modules internal pull-up current source,
turning the module off. When the DRAIN voltage drops
below V
DL
 and the GATE voltage is high, Q2 will turn on
and the PWRGD pin will pull low, enabling the module.
The PWRGD signal can also be used to turn on an LED
oroptoisolator to indicate that the power is good as shown
in Figure 14.
Gate Pin Voltage Regulation
When the supply voltage to the chip is more than 18V ,
the GATE pin voltage is regulated at 13.5V above V
EE
.
The gate voltage will be no greater than 18V for supply
voltages up to 80V .
V
EE
V
DD
LT4250L/LT4250H
R4
R5
R6
4
4250 F11
OV
48V RTN
3
2
48V
UV
8
V
UV
 = 1.255
R4 + R5+ R6
R5 + R6
(
)
V
OV
 = 1.255
R4 + R5+ R6
R6
(
)
48V RTN
(SHORT PIN)
+
V
EE
V
DD
LT4250H
SENSE
C1
C3
Q1
R2
R3
C2
R4
R5
R6
R1
4
3
2
OV
48V RTN
48V
UV
5
6
8
1
7
GATE
4250 F12
PWRGD
DRAIN
V
EE
Q3
ACTIVE HIGH
ENABLE MODULE
V
OUT
+
V
OUT

V
IN
+
V
IN

ON/OFF
48V RTN
(SHORT PIN)
*
* DIODES INC. SMAT70A
4
3
2
1
Q2
V
DL
V
GH
+

+

+

+

GATE
GATE
I
1
Figure 11. Undervoltage and Overvoltage Sensing
Figure 12. Active High Enable Module
相关PDF资料
PDF描述
VI-B11-CY-F3 CONVERTER MOD DC/DC 12V 50W
ACM30DRMN CONN EDGECARD 60POS .156 WW
GMC05DREF CONN EDGECARD 10POS .100 EYELET
VE-B1R-CY-F4 CONVERTER MOD DC/DC 7.5V 50W
R2S12-153.3 CONV DC/DC 2W 15VIN 3.3VOUT SMD
相关代理商/技术参数
参数描述
LT4250HIN8#PBF 功能描述:IC CONTRLR HOT SWAP NEG 48V 8DIP 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
LT4250HIS8 功能描述:IC CONTRLR HOTSWAP NEG 48V 8SOIC 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
LT4250HIS8#PBF 功能描述:IC CONTRLR HOTSWAP NEG 48V 8SOIC 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
LT4250HIS8#TR 功能描述:IC CONTRLR HOTSWAP NEG 48V 8SOIC 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
LT4250HIS8#TRPBF 功能描述:IC CONTRLR HOTSWAP NEG 48V 8SOIC 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