- 您現在的位置：買賣IC網 > Datasheet目錄42 > LTC4253ACGN#TRPBF (Linear Technology)IC HOT SWAP CONTRLR -48V 16-SSOP Datasheet資料下載
參數資料
| 型號： | LTC4253ACGN#TRPBF |
| 廠商： | Linear Technology |
| 文件頁數： | 21/34頁 |
| 文件大?。?/td> | 383K |
| 描述： | IC HOT SWAP CONTRLR -48V 16-SSOP |
| 標準包裝： | 2,500 |
| 類型： | 熱交換控制器 |
| 應用： | 通用 |
| 內部開關： | 無 |
| 電源電壓： | 8.2 V ~ 14.5 V |
| 工作溫度： | 0°C ~ 70°C |
| 安裝類型： | 表面貼裝 |
| 封裝/外殼： | 16-SSOP（0.154"，3.90mm 寬） |
| 供應商設備封裝： | 16-SSOP |
| 包裝： | 帶卷 (TR) |
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第8頁第9頁第10頁第11頁第12頁第13頁第14頁第15頁第16頁第17頁第18頁第19頁第20頁當前第21頁第22頁第23頁第24頁第25頁第26頁第27頁第28頁第29頁第30頁第31頁第32頁第33頁第34頁
LTC4253/LTC4253A
21
425353aff
For more information www.linear.com/4253
Computing the maximum soft-start capacitor value during
soft-start to a load short is complicated by the nonlinear
MOSFETs SOA characteristics and the R
SS
C
SS
response.
An overconservative but simple approach begins with the
maximum circuit breaker current, given by:
I
CB(MAX)
=
V
CB(MAX)
R
S
(14)
where V
CB(MAX)
is 60mV (55mV for the LTC4253A).
From the SOA curves of a prospective MOSFET , determine
the time allowed, t
SOA(MAX)
. C
SS
is given by:
C
SS
=
t
SOA(MAX)
0.916 R
SS
for the LTC4253
C
SS
=
t
SOA(MAX)
2.48 R
SS
for the LTC4253A
(15)
In the above example, 60mV/40m?gives 1.5A. t
SOA
for
the IRF530S is 40ms. From Equation (15), C
SS
= 437nF .
Actual board evaluation showed that C
SS
= 100nF was ap-
propriate. The ratio ( R
SS
"
C
SS
) to t
CL(CHARGE)
is a good
gauge as large ratios may result in the time-out period
expiring prematurely. This gauge is determined empirically
with board level evaluation.
SUMMARY OF DESIGN FLOW
To summarize the design flow, consider the application
shown in Figure 3 for the LTC4253A. It was designed for
80W and C
L
??00礔 .
Calculate maximum load current: 80W/43V = 1.86A;
allowing for 83% converter efficiency, I
IN(MAX)
= 2.2A.
Calculate R
S
: from Equation (8) R
S
= 20m?
Calculate I
SHORT-CIRCUIT(MAX)
: from Equation (10)
I
SHORTCIRCUIT(MAX)
= 3.3A.
Select a MOSFET that can handle 3.3A at 71V: IRF530S.
Calculate C
T
: from Equation (13) C
T
= 302nF . Select
C
T
?=?680nF , which gives the circuit breaker time-out
period t
MAX
= 5.9ms.
Consult MOSFET SOA curves: the IRF530S can handle 3.3A
at 100V for 8.3ms, so it is safe to use in this application.
Calculate C
SS
: using Equations (14) and (15) select
C
SS
??3nF .
FREQUENCY COMPENSATION
The LTC4253 typical frequency compensation network
for the analog current limit loop is a series R
C
(10?
and C
C
connected from GATE to V
EE
. Figure 6 depicts the
relationship between the compensation capacitor C
C
and
the MOSFETs C
ISS
. The line in Figure 6 is used to select
a starting value for C
C
based upon the MOSFETs C
ISS
specification. Optimized values for C
C
are shown for sev-
eral popular MOSFETs. Differences in the optimized value
of C
C
versus the starting value are small. Nevertheless,
compensation values should be verified by board level
short-circuit testing.
As seen in Figure 5, at the onset of a short-circuit event,
the input supply voltage can ring dramatically due to series
inductance. If this voltage avalanches the MOSFET , current
continues to flow through the MOSFET to the output. The
analog current limit loop cannot control this current flow
and therefore the loop undershoots. This effect cannot be
eliminated by frequency compensation. A Zener diode is
required to clamp the input supply voltage and prevent
MOSFET avalanche.
Figure 6. Recommended Compensation
Capacitor C
C
vs MOSFET C
ISS
for the LTC4253
MOSFET C
ISS
(pF)
4253 F06
60
50
40
30
20
10
0
0
2000
4000
6000
8000
IRF530
IRF540
IRF740
IRF3710
NTY100N10
APPLICATIONS INFORMATION
相關PDF資料 |
PDF描述 |
|---|---|
| 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 |
相關代理商/技術參數 |
參數描述 |
|---|---|
| LTC4253ACUF-ADJ#PBF | 制造商:Linear Technology 功能描述:Hot Swap Controller 1-CH 20-Pin QFN EP |
| LTC4253ACUF-ADJ#TRPBF | 制造商:Linear Technology 功能描述:Hot Swap Controller 1-CH 20-Pin QFN EP T/R |
| LTC4253AIGN#PBF | 功能描述:IC HOT SWAP CONTRLR -48V 16-SSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 熱交換 系列:- 產品培訓模塊:Obsolescence Mitigation Program 標準包裝:100 系列:- 類型:熱插拔開關 應用:通用 內部開關:是 電流限制:可調 電源電壓:9 V ~ 13.2 V 工作溫度:-40°C ~ 150°C 安裝類型:表面貼裝 封裝/外殼:10-WFDFN 裸露焊盤 供應商設備封裝:10-TDFN-EP（3x3） 包裝:管件 |
| LTC4253AIGN#TRPBF | 功能描述:IC HOT SWAP CONTRLR -48V 16-SSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 熱交換 系列:- 產品培訓模塊:Obsolescence Mitigation Program 標準包裝:100 系列:- 類型:熱插拔開關 應用:通用 內部開關:是 電流限制:可調 電源電壓:9 V ~ 13.2 V 工作溫度:-40°C ~ 150°C 安裝類型:表面貼裝 封裝/外殼:10-WFDFN 裸露焊盤 供應商設備封裝:10-TDFN-EP（3x3） 包裝:管件 |
| LTC4253AIGN-ADJ | 制造商:LINER 制造商全稱:Linear Technology 功能描述:-48V Hot Swap Controller with Sequencer |
發布緊急采購，3分鐘左右您將得到回復。