- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄377723 > LT3437 (Linear Technology Corporation) Panels; For Use With:EUROCARD Subracks RoHS Compliant: Yes PDF資料下載
參數(shù)資料
| 型號： | LT3437 |
| 廠商： | Linear Technology Corporation |
| 英文描述： | Panels; For Use With:EUROCARD Subracks RoHS Compliant: Yes |
| 中文描述： | 高電壓，200kHz降壓500mA的降壓開關(guān)穩(wěn)壓器以100？的靜態(tài)電流 |
| 文件頁數(shù)： | 19/24頁 |
| 文件大小： | 523K |
| 代理商： | LT3437 |
LT3437
19
3437f
APPLICATIOU
(t
r
+ t
f
+ t
IR
+ t
IF
)
t
r
= (V
IN
/0.6)ns
t
f
= (V
IN
/2)ns
t
IR
= t
IF
= (I
OUT
/0.05)ns
f = switch frequency
Example: with V
= 40V, V
OUT
= 5V and I
OUT
= 250mA:
W
U
U
P
e
W
P
W
P
W
SW
BOOST
Q
=
( )(
) ( )
+
( )
( )
(
=
=
( )
(
40 0 0005
.
)( )(
)
+
)
=
=
)
+
)
=
5
40
/
.
0 008
.
0 092
.
0 1
.
5
0 2530
40
0 005
.
5 0 0008
.
0 024
.
2
2
.
.
/
Total power dissipation is:
P
TOT
= 0.1 + 0.065 + 0.024 = 0.13W
Thermal resistance for the LT3437 package is influenced
by the presence of internal or backside planes. With a full
plane under the package, thermal resistance will be about
45
°
C for the FE and DD packages. No plane will increase
resistance to about 150
°
C/W. To calculate die temperature,
use the proper thermal resistance number for the desired
package and add in worst-case ambient temperature:
T
J
= T
A
+ Q
JA
(P
TOT
)
With the DD package (Q
JA
= 45
°
C/W) at an ambient
temperature of 70
°
C:
T
J
= 70 + 45(0.1) = 74.5
°
C
Input Voltage vs Operating Frequency Considerations
The absolute maximum input supply voltage for the LT3437
is specified at 80V. This is based solely on internal semi-
conductor junction breakdown effects. Due to internal
power dissipation, the actual maximum V
IN
achievable in
a particular application may be less than this.
A detailed theoretical basis for estimating internal power
loss is given in the section Thermal Considerations. Note
that AC switching loss is proportional to both operating
frequency and output current. The majority of AC switch-
ing loss is also proportional to the square of input voltage.
For example, while the combination of V
IN
= 40V, V
OUT
=
5V at 700mA and f
OSC
= 200kHz may be easily achievable,
simultaneously raising V
IN
to 80V and f
OSC
to 700kHz is not
possible. Nevertheless, input voltage transients up to 80V
can usually be accommodated, assuming the resulting
increase in internal dissipation is of insufficient time dura-
tion to raise die temperature significantly.
A second consideration is controllability. A potential limi-
tation occurs with a high step-down ratio of V
IN
to V
OUT
,
as this requires a correspondingly narrow minimum switch
on time. An approximate expression for this (assuming
continuous mode operation) is given as follows:
t
ON(MIN)
= (V
OUT
+ V
F
)/V
IN
(f
OSC
)
where:
V
IN
= input voltage
V
OUT
= output voltage
V
F
= Schottky diode forward drop
f
OSC
= switching frequency
A potential controllability problem arises if the LT3437 is
called upon to produce an on time shorter than it is able to
produce. Feedback loop action will lower, then reduce, the
V
C
control voltage to the point where some sort of cycle-
skipping or Burst Mode behavior is exhibited.
In summary:
1. Be aware that the simultaneous requirements of high
V
IN
, high I
OUT
and high f
OSC
may not be achievable in
practice due to internal dissipation. The Thermal Con-
siderations section offers a basis to estimate internal
power. In questionable cases, a prototype supply should
be built and exercised to verify acceptable operation.
2. The simultaneous requirements of high V
IN
, low V
OUT
and high f
OSC
can result in an unacceptably short mini-
mum switch on time. Cycle skipping and/or Burst Mode
behavior will result causing an increase in output volt-
age ripple while maintaining the correct output voltage.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LT3437IFE | MOSFET N-CHANNEL 100V SOT323 |
| LT3437EFE | RADIATION HARDENED HIGH EFFICIENCY, 5 AMP SWITCHING REGULATORS |
| LT3460 | 1.3MHz Step-Up DC/DC Converter in SC70 and ThinSOT |
| LT3460ESC6 | 1.3MHz Step-Up DC/DC Converter in SC70 and ThinSOT |
| LT3460ES5 | 1.3MHz Step-Up DC/DC Converter in SC70 and ThinSOT |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LT3437_1 | 制造商:LINER 制造商全稱:Linear Technology 功能描述:High Voltage 500mA, 200kHz Step-Down Switching Regulator with 100μA Quiescent Current |
| LT3437EDD | 制造商:Linear Technology 功能描述:Conv DC-DC Single Step Down 3.3V to 60V 10-Pin DFN EP |
| LT3437EDD#PBF | 功能描述:IC REG BUCK ADJ 0.5A 10DFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關(guān)穩(wěn)壓器 系列:- 設(shè)計資源:Design Support Tool 標(biāo)準(zhǔn)包裝:1 系列:- 類型:升壓（升壓） 輸出類型:固定 輸出數(shù):1 輸出電壓:3V 輸入電壓:0.75 V ~ 2 V PWM 型:- 頻率 - 開關(guān):- 電流 - 輸出:100mA 同步整流器:是 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:SOT-23-5 細(xì)型，TSOT-23-5 包裝:剪切帶 (CT) 供應(yīng)商設(shè)備封裝:TSOT-23-5 其它名稱:AS1323-BTTT-30CT |
| LT3437EDD#TRPBF | 功能描述:IC REG BUCK ADJ 0.5A 10DFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關(guān)穩(wěn)壓器 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- 類型:升壓（升壓） 輸出類型:可調(diào)式 輸出數(shù):1 輸出電壓:1.24 V ~ 30 V 輸入電壓:1.5 V ~ 12 V PWM 型:電流模式，混合 頻率 - 開關(guān):600kHz 電流 - 輸出:500mA 同步整流器:無 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:8-SOIC（0.154"，3.90mm 寬） 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:8-SOIC |
| LT3437EFE | 制造商:Linear Technology 功能描述:Conv DC-DC Single Step Down 3.3V to 60V 16-Pin TSSOP EP |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。