參數(shù)資料
型號(hào)： LTC4240CGN
廠商： LINEAR TECHNOLOGY CORP
元件分類： 電源管理
英文描述： CompactPCI Hot Swap Controller with I2C Compatible Interface
中文描述： 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO28
封裝： 0.150 INCH, PLASTIC, SSOP28
文件頁(yè)數(shù)： 19/28頁(yè)
文件大?。?/td> 486K
代理商： LTC4240CGN
LTC4240
19
Once the TIMER voltage has reached 5.5V, all of the
supplies will be latched off if any supply enters current
limit for at least 35
μ
s. The 35
μ
s delay prevents quick
current spikes—for example, from a fan turning on—
from causing false trips of the circuit breaker.
During normal operation, the 5V and 3.3V supplies are
protected from overcurrent and short-circuit conditions
by dual-level circuit breakers. In the event that either
supply current exceeds the nominal limit, an internal timer
is started. If the supply is still overcurrent after 35
μ
s, the
circuit breaker trips and all the supplies are turned off
(Figure 7). If a short-circuit occurs on 5V
OUT
or 3V
OUT
and
the supply current exceeds three times the set limit, an
analog loop will limit the current to 3 times the value set
by R
SENSE
and 55mV. If the short persists for more than
35
μ
s, the LTC4240 latches off (Figure 8). It will stay in the
latched off state until it is reset using the OFF/ON pin or by
using the I
2
C interface. The LTC4240 can also be reset by
cycling any of the power supplies.
The current limit and the foldback current level for the 5V
and 3.3V outputs are both a function of the external sense
resistor (R1 for 3V
OUT
and R2 for 5V
OUT
, see front page).
A sense resistor is connected between 5V
IN
(Pin 21) and
5V
SENSE
(Pin 20) for the 5V supply. For the 3.3V supply, a
sense resistor is connected between 3V
IN
(Pin 22) and
3V
SENSE
(Pin 23). The current limit and the current foldback
current level are given by Equations 4 and5:
I
mV
R
I
mV
R
LIMIT XVOUT
(
SENSE XVOUT
(
FOLDBACK XVOUT
SENSE XVOUT
(
)
)
(
)
)
( )
4
( )
5
=
=
55
11
where XV
OUT
= 5V
OUT
or 3V
OUT
.
Equation 4 is the current limit for XV
OUT
≈
XV
IN
. Equation
5 shows the I
LIMIT
for shorted outputs. Both equations
assume voltage on TIMER pin is greater than 5.5V.
XV
OUT
= 3V
OUT
or 5V
OUT
. Note that since there are only 8
pins connecting 5V
IN
, R
SENSE
≥
0.007
for 5V
IN
.
The current limit for the internal 12V switch is set at
–1200mA folding back to –350mA and the –12V switch at
500mA folding back to 250mA.
Selecting R
SENSE
An equivalent circuit for the 5V and 3.3V circuit breakers
is shown in Figure 9. The sense resistor and the circuit
breaker threshold voltage determine the fault current that
turns off the external FETs. Sense resistors with a 1%
tolerance are recommended. Due to part to part and
temperature variations for both the sense resistor value
and the circuit breaker threshold voltage, the actual cur-
rent limit threshold will exhibit some variation. To calcu-
late the smallest value of current that will trip the fault
comparator, use the largest value of the sense resistor and
the smallest value of the threshold voltage. A 0.005
1%
sense resistor (on the 3.3V supply, for example) with
typical temperature coefficients would increase to ap-
proximately 0.0051
(nominal value multiplied by the 1%
tolerance and the TC at 70
°
C). Since the minimum value of
the threshold voltage is 50mV, this implies a current limit
of 9.8A. To arrive at the largest value of the current limit
that will turn off the external FETs, the nominal value of the
APPLICATIU
W
U
U
Figure 7. Overcurrent Fault on 5V
Figure 8. Short-Circuit Fault on 5V
GATE
5V/DIV
5V
IN
–5V
SENSE
100mV/DIV
FAULT
5V/DIV
20
μ
s/DIV
4240 F07
GATE
5V/DIV
5V
IN
–5V
SENSE
100mV/DIV
FAULT
5V/DIV
20
μ
s/DIV
4240 F08
相關(guān)PDF資料
PDF描述
LTC4244 Rugged, CompactPCI Bus Hot Swap Controllers
LTC4244CGN-1 Rugged, CompactPCI Bus Hot Swap Controllers
LTC4244IGN Rugged, CompactPCI Bus Hot Swap Controllers
LTC4244IGN-1 Rugged, CompactPCI Bus Hot Swap Controllers
LTC4244CGN Rugged, CompactPCI Bus Hot Swap Controllers
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LTC4240CGN#PBF 功能描述:IC CTLR HOT SWAP CPCI I2C 28SSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 熱交換 系列:- 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:119 系列:- 類型:熱交換控制器 應(yīng)用:通用型，PCI Express? 內(nèi)部開關(guān):無(wú) 電流限制:- 電源電壓:3.3V，12V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:80-TQFP 供應(yīng)商設(shè)備封裝:80-TQFP（12x12） 包裝:托盤 產(chǎn)品目錄頁(yè)面:1423 (CN2011-ZH PDF)
LTC4240CGN#TR 功能描述:IC CTRLR HOT SWAP CPCI 28-SSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 熱交換 系列:- 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:119 系列:- 類型:熱交換控制器 應(yīng)用:通用型，PCI Express? 內(nèi)部開關(guān):無(wú) 電流限制:- 電源電壓:3.3V，12V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:80-TQFP 供應(yīng)商設(shè)備封裝:80-TQFP（12x12） 包裝:托盤 產(chǎn)品目錄頁(yè)面:1423 (CN2011-ZH PDF)
LTC4240CGN#TRPBF 功能描述:IC CTRLR HOTSWAP CPCI I2C 28SSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 熱交換 系列:- 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:119 系列:- 類型:熱交換控制器 應(yīng)用:通用型，PCI Express? 內(nèi)部開關(guān):無(wú) 電流限制:- 電源電壓:3.3V，12V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:80-TQFP 供應(yīng)商設(shè)備封裝:80-TQFP（12x12） 包裝:托盤 產(chǎn)品目錄頁(yè)面:1423 (CN2011-ZH PDF)
LTC4240IGN 功能描述:IC CTRLR HOT SWAP CPCI 28-SSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 熱交換 系列:- 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:119 系列:- 類型:熱交換控制器 應(yīng)用:通用型，PCI Express? 內(nèi)部開關(guān):無(wú) 電流限制:- 電源電壓:3.3V，12V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:80-TQFP 供應(yīng)商設(shè)備封裝:80-TQFP（12x12） 包裝:托盤 產(chǎn)品目錄頁(yè)面:1423 (CN2011-ZH PDF)
LTC4240IGN#PBF 功能描述:IC CTRLR HOTSWAP CPCI I2C 28SSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 熱交換 系列:- 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:119 系列:- 類型:熱交換控制器 應(yīng)用:通用型，PCI Express? 內(nèi)部開關(guān):無(wú) 電流限制:- 電源電壓:3.3V，12V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:80-TQFP 供應(yīng)商設(shè)備封裝:80-TQFP（12x12） 包裝:托盤 產(chǎn)品目錄頁(yè)面:1423 (CN2011-ZH PDF)
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。

采購(gòu)需求

(若只采購(gòu)一條型號(hào)，填寫一行即可)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

*型號(hào) *數(shù)量 廠商 批號(hào) 封裝
添加更多采購(gòu)

我的聯(lián)系方式

*
*
*