- 您现在的位置：买卖IC网 > PDF目录22130 > LTC4244IGN-1#TR (Linear Technology)IC CTRLR HOT SWAP CPCI 20-SSOP PDF资料下载
参数资料
| 型号： | LTC4244IGN-1#TR |
| 厂商： | Linear Technology |
| 文件页数： | 23/28页 |
| 文件大小： | 337K |
| 描述： | IC CTRLR HOT SWAP CPCI 20-SSOP |
| 标准包装： | 2,500 |
| 类型： | 热交换控制器 |
| 应用： | CompactPCI? |
| 内部开关： | 无 |
| 电源电压： | 3.3V，5V，±12V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 20-SSOP（0.154"，3.90mm 宽） |
| 供应商设备封装： | 20-SSOP |
| 包装： | 带卷 (TR) |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页当前第23页第24页第25页第26页第27页第28页
23
LTC4244/LTC4244-1
42441f
the PC board. For 1 ounce copper foil plating, a general rule
is 1 ampere of DC current per via making sure the via is
properly dimensioned so that solder completely fills the
void. For other plating thicknesses, check with your PCB
fabrication facility.
Design Example
As a design example, consider a CPCI Hot Swap applica-
tion with the following power supply requirements:
Table 4. Design Example Power Supply Requirements
VOLTAGE
MAXIMUM DC
LOAD
SUPPLY
SUPPLY CURRENT
CAPACITANCE
12V
450mA
100礔
5V
5A
2200礔
3.3V
7A
2200礔
12V
100mA
100礔
The first step is to select the appropriate values of R
SENSE
for the 5V and 3.3V supplies. Calculating the value of
R
SENSE
is based on I
LOAD(MAX)
and the lower limit for the
circuit breaker threshold voltage (47mV for both the 5V
and 3.3V circuit breakers). If a 1% tolerance is assumed
for the sense resistors, then 5m& and 7m& resistor
values yield the following minimum and maximum I
TRIP
values:
Table 5. I
TRIP
vs R
SENSE
R
SENSE
(1% RTOL)
I
TRIP(MIN)
I
TRIP(MAX)
5m&
9.3A
11.5A
7m&
6.6A
8.2A
So sense resistor values of 7m& and 5m& should suffice
for the 5V and 3.3V supplies, respectively.
The second step is to select MOSFETs for the 5V and 3.3V
supplies. The IRF7457s on resistance is less than 10.5m&
for V
GS
> 4.5V and a junction temperature of 25癈. Since
the maximum load current requirement for the 3.3V sup-
ply is 7A, the steady-state power the device may be
required to dissipate is 514mW. The IRF7457 has a
junction-to-ambient thermal resistance of 50癈/Watt. If a
maximum ambient temperature of 50癈 is assumed, this
yields a junction temperature of 75.7癈. According to the
IRF7457s Normalized On-Resistance vs Junction Tem-
perature curve, the devices on-resistance can be expected
to increase by about 20% over its room temperature value.
Recalculation of the steady-state values of R
ON
and junc-
tion temperature yields approximately 12.6m& and 81癈,
respectively. The I " R drop across the 3.3V sense resistor
and series MOSFET at maximum load current under these
conditions will be less than 124mV.
The next step is to select appropriate values for C1
and
C
TIMER
. Assuming that the total current for the 5V supply
is constrained to less than 6A during power-up (6 ?5V
medium length connector pins at 1A per pin), then the
inrush current shouldnt exceed:
I
INRUSH
< 6A I
LOAD(5VOUT)
= 6A 5A = 1A
(12)
This yields:
C
I
F
I
C
A
F
A
nF
GATE MAX
INRUSHMAX
1
2200
1
100
2200
1
220
>
?/DIV>
?nbsp >
?/DIV>
?/DIV>
=
(
)
(
)
"
"
(13)
Hence a C1 value of 330nF ?0% should suffice. The value
of C
TIMER
for this design example will be constrained by
the duration of the 12V supply inrush current, which
according to Equation 2 is:
t
C
V
I
I
t
F
V
mA
mA
ms
ON VOUT
LOAD
LIMIT MIN LOAD MAX
ON VOUT
(
)
( )
(
)
(
)
"
"
"
"
12
12
2
12
2 100
12
550
450
24
<
?/DIV>
<
?/DIV>
=
(14)
In order to guarantee that the LTC4244s TIMER fault
inhibit period is greater than 24ms, the value of C
TIMER
should be:
C
ms I
V V
C
ms
A
V
V
nF
TIMER
TIMER MAX
TIMER MAX
TIMER
>
?/DIV>
>
?/DIV>
=
24
12
24
26
12 1 9
61 8
"
"
.
.
(
)
(
)
(15)
So a value of 82nF (?0%) should suffice.
APPLICATIO S I FOR ATIO
U
U
U
相关PDF资料 |
PDF描述 |
|---|---|
| LTC1643AHIGN#TR | IC CTRLR HOTSWAP PCI BUS 16SSOP |
| RBM06DCBD | CONN EDGECARD 12POS R/A .156 SLD |
| B280-13-F | DIODE SCHOTTKY 2A 80V SMB |
| LTC1643ALIGN#TRPBF | IC CTRLR HOTSWAP PCI BUS 16SSOP |
| R2S8-2424/P | CONV DC/DC 2W 24VIN 24VOUT SMD |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC4244IGNTR | 制造商:Linear Technology 功能描述: |
| LTC4245 | 制造商:LINER 制造商全称:Linear Technology 功能描述:Dual Supply Hot Swap Controller for Advanced Mezzanine Card |
| LTC4245CG | 制造商:LINER 制造商全称:Linear Technology 功能描述:Multiple Supply Hot Swap Controller with I2C Compatible Monitoring |
| LTC4245CG#PBF | 功能描述:IC CNTRLR HOT SWAP 36-SSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 热交换 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:119 系列:- 类型:热交换控制器 应用:通用型，PCI Express? 内部开关:无 电流限制:- 电源电压:3.3V，12V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:80-TQFP 供应商设备封装:80-TQFP（12x12） 包装:托盘 产品目录页面:1423 (CN2011-ZH PDF) |
| LTC4245CG#TRPBF | 功能描述:IC CNTRLR HOT SWAP 36-SSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 热交换 系列:- 产品培训模块:Obsolescence Mitigation Program 标准包装:100 系列:- 类型:热插拔开关 应用:通用 内部开关:是 电流限制:可调 电源电压:9 V ~ 13.2 V 工作温度:-40°C ~ 150°C 安装类型:表面贴装 封装/外壳:10-WFDFN 裸露焊盘 供应商设备封装:10-TDFN-EP（3x3） 包装:管件 |
发布紧急采购，3分钟左右您将得到回复。