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參數(shù)資料
| 型號： | LTC1159IS-5 |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | RADIATION HARDENED HIGH EFFICIENCY, 5 AMP SWITCHING REGULATORS |
| 中文描述： | 0.05 A SWITCHING CONTROLLER, 250 kHz SWITCHING FREQ-MAX, PDSO16 |
| 封裝： | 0.150 INCH, PLASTIC, SO-16 |
| 文件頁數(shù)： | 9/20頁 |
| 文件大?。?/td> | 288K |
| 代理商： | LTC1159IS-5 |
9
LTC1159
LTC1159-3.3/LTC1159-5
inductor ripple current and consequent output voltage
ripple which can cause Burst Mode operation to be falsely
triggered in the LTC1159. Do not allow the core to saturate!
Molypermalloy (from Magnetics, Inc.) is a low loss core
material for toroids, but it is more expensive than ferrite.
A reasonable compromise from the same manufacturer is
Kool M
μ
. Toroids are very space efficient, especially when
you can use several layers of wire. Because they generally
lack a bobbin, mounting is more difficult. However, new
surface mount designs available from Coiltronics do not
increase the height significantly.
Power MOSFET Selection
Two external power MOSFETs must be selected for use
with the LTC1159: a P-channel MOSFET for the main
switch and an N-channel MOSFET for the synchronous
switch.
The peak-to-peak drive levels are set by the V
CC
voltage on
the LTC1159. This voltage is typically 4.5V during start-up
and 5V to 7V during normal operation (see EXTV
CC
Pin
Connection). Consequently, logic-level threshold
MOSFETs must be used in most LTC1159 family applica-
tions The only exception is applications in which EXTV
CC
is powered from an external supply greater than 8V, in
which standard threshold MOSFETs (V
GS(TH)
< 4V) may be
used. Pay close attention to the BV
DSS
specification for the
MOSFETs as well; many of the logic-level MOSFETs are
limited to 30V.
Selection criteria for the power MOSFETs include the “ON”
resistance R
DS(ON)
, reverse transfer capacitance C
RSS
,
input voltage and maximum output current. When the
LTC1159 is operating in continuous mode, the duty cycle
for the P-channel MOSFET is given by:
P-Ch Duty Cycle =V
OUT
V
IN
N-Ch Duty Cycle =V
IN
–
V
OUT
V
IN
The MOSFET dissipations at maximum output current are
given by:
N-Ch P
D
=V
IN
–
V
OUT
V
IN
(I
MAX
)
2
(1 +
N
) R
DS(ON)
P-Ch P
D
=V
OUT
V
IN
k(V
IN
)
2
(I
MAX
) (C
RSS
) (f)
(I
MAX
)
2
(1 +
P
) R
DS(ON)
+
where
is the temperature dependency of R
DS(ON)
and k
is a constant inversely related to the gate drive current.
Both MOSFETs have I
2
R losses while the P-channel
equation includes an additional term for transition losses,
which are highest at high input voltages. For V
IN
< 20V the
high current efficiency generally improves with larger
MOSFETs, while for V
IN
> 20V the transition losses rapidly
increase to the point that the use of a higher R
DS(ON)
device with lower C
RSS
actually provides higher effi-
ciency. The N-channel MOSFET losses are the greatest at
high input voltage or during a short circuit when the
N-channel duty cycle is nearly 100%.
The term (1 +
) is generally given for a MOSFET in the form
of a normalized R
DS(ON)
vs Temperature curve, but
= 0.007/
°
C can be used as an approximation for low
voltage MOSFETs. C
RSS
is usually specified in the MOSFET
electrical characteristics. The constant k = 5 can be used for
the LTC1159 to estimate the relative contributions of the
two terms in the P-channel dissipation equation.
The Schottky diode D1 shown in Figure 1 only conducts
during the dead time between the conduction of the two
power MOSFETs. D1 prevents the body diode of the
N-channel MOSFET from turning on and storing charge
during the dead time, which could cost as much as 1% in
efficiency (although there are no other harmful effects if
D1 is omitted). Therefore, D1 should be selected for a
forward voltage of less than 0.6V when conducting I
MAX
.
APPLICATIU
W
U
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| LTC1159IS-5#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 16-SOIC RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標準包裝:4,500 系列:PowerWise® PWM 型:控制器 輸出數(shù):1 頻率 - 最大:1MHz 占空比:95% 電源電壓:2.8 V ~ 5.5 V 降壓:是 升壓:無 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 125°C 封裝/外殼:6-WDFN 裸露焊盤 包裝:帶卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名稱:LM1771SSDX |
| LTC1159IS-5#TR | 功能描述:IC REG CTRLR BUCK PWM CM 16-SOIC RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標準包裝:4,500 系列:PowerWise® PWM 型:控制器 輸出數(shù):1 頻率 - 最大:1MHz 占空比:95% 電源電壓:2.8 V ~ 5.5 V 降壓:是 升壓:無 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 125°C 封裝/外殼:6-WDFN 裸露焊盤 包裝:帶卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名稱:LM1771SSDX |
| LTC1159IS-5#TRPBF | 功能描述:IC REG CTRLR BUCK PWM CM 16-SOIC RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標準包裝:4,500 系列:PowerWise® PWM 型:控制器 輸出數(shù):1 頻率 - 最大:1MHz 占空比:95% 電源電壓:2.8 V ~ 5.5 V 降壓:是 升壓:無 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 125°C 封裝/外殼:6-WDFN 裸露焊盤 包裝:帶卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名稱:LM1771SSDX |
| LTC1160CN | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Interface IC |
| LTC1160CS | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Interface IC |
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