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参数资料
| 型号： | LT1766HGN#PBF |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 稳压器 |
| 英文描述： | 3 A SWITCHING REGULATOR, 228 kHz SWITCHING FREQ-MAX, PDSO16 |
| 封装： | 0.150 INCH, LEAD FREE, PLASTIC, SSOP-16 |
| 文件页数： | 4/28页 |
| 文件大小： | 284K |
| 代理商： | LT1766HGN#PBF |
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12
LT1766/LT1766-5
1766fb
materials fall somewhere in between. The following for-
mula assumes continuous mode of operation, but errs
only slightly on the high side for discontinuous mode, so
it can be used for all conditions.
II
I
VV
V
Vf L
PEAK
OUT
LP P
OUT
IN
OUT
IN
=+
=+ ()(
)
()( )( )()
()
–
-
2
EMI
Decide if the design can tolerate an “open” core geometry
like a rod or barrel, which have high magnetic field
radiation, or whether it needs a closed core like a toroid to
prevent EMI problems. This is a tough decision because
the rods or barrels are temptingly cheap and small and
there are no helpful guidelines to calculate when the
magnetic field radiation will be a problem.
Additional Considerations
After making an initial choice, consider additional factors
such as core losses and second sourcing, etc. Use the
experts in Linear Technology’s Applications department if
you feel uncertain about the final choice. They have
experience with a wide range of inductor types and can tell
you about the latest developments in low profile, surface
mounting, etc.
Maximum Output Load Current
Maximum load current for a buck converter is limited by
the maximum switch current rating (IP). The current rating
for the LT1766 is 1.5A. Unlike most current mode convert-
ers, the LT1766 maximum switch current limit does not
fall off at high duty cycles. Most current mode converters
suffer a drop off of peak switch current for duty cycles
above 50%. This is due to the effects of slope compensa-
tion required to prevent subharmonic oscillations in cur-
rent mode converters. (For detailed analysis, see Applica-
tion Note 19.)
The LT1766 is able to maintain peak switch current limit over
the full duty cycle range by using patented circuitry* to cancel
the effects of slope compensation on peak switch current
without affecting the frequency compensation it provides.
APPLICATIO S I FOR ATIO
WU
UU
Maximum load current would be equal to maximum
switch current
for an infinitely large inductor, but with
finite inductor size, maximum load current is reduced by
one-half peak-to-peak inductor current (ILP-P). The follow-
ing formula assumes continuous mode operation, imply-
ing that the term on the right is less than one-half of IP.
IOUT(MAX) =
Continuous Mode
I–
I
2
= I
P
LP-P
P
+
()
()
()( )( )
VV
V
Lf V
OUT
F
IN
OUT
F
IN
–
2
For VOUT = 5V, VIN = 8V, VF(D1) = 0.63V, f = 200kHz and
L = 20
H:
I
A
OUT MAX
()
=
+
()
()
()(
)()
=
=
15
5 0 63 8 5 0 63
2 20 10
200 10
8
15
0 21 129
63
.
.– .
..
.
Note that there is less load current available at the higher
input voltage because inductor ripple current increases. At
VIN = 15V, duty cycle is 33% and for the same set of
conditions:
I
A
OUT MAX
()
.
.– .
..
.
=
+
()
()
()(
)()
=
=
15
5 0 63 15 5 0 63
2 20 10
200 10
15
15 044
106
63
To calculate actual peak switch current with a given set of
conditions, use:
II
I
VV V
V
Lf V
SW PEAK
OUT
P
OUT
F
IN
OUT
F
IN
() =+
=+
+
()
()( )( )
I
2
L-P
()
–
2
Reduced Inductor Value and Discontinuous Mode
If the smallest inductor value is of most importance to a
converter design, in order to reduce inductor size/cost,
discontinuous mode may yield the smallest inductor solu-
tion. The maximum output load current in discontinuous
mode, however, must be calculated and is defined later in
this section.
*Patent # 6, 498, 466
相关PDF资料 |
PDF描述 |
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| LT1776IS8#TR | 1 A SWITCHING REGULATOR, 230 kHz SWITCHING FREQ-MAX, PDSO8 |
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| LT1871IMS-7 | SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PDSO10 |
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LT1766IFE | 功能描述:IC REG BUCK ADJ 1.5A 16TSSOP RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 设计资源:Design Support Tool 标准包装:1 系列:- 类型:升压（升压） 输出类型:固定 输出数:1 输出电压:3V 输入电压:0.75 V ~ 2 V PWM 型:- 频率 - 开关:- 电流 - 输出:100mA 同步整流器:是 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:SOT-23-5 细型，TSOT-23-5 包装:剪切带 (CT) 供应商设备封装:TSOT-23-5 其它名称:AS1323-BTTT-30CT |
| LT1766IFE#PBF | 功能描述:IC REG BUCK ADJ 1.5A 16TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 产品培训模块:MIC23xxx HyperLight Load™ Regulators 标准包装:5,000 系列:HyperLight Load® 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:1.8V 输入电压:2.7 V ~ 5.5 V PWM 型:混合物 频率 - 开关:4MHz 电流 - 输出:2A 同步整流器:是 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:8-VFDFN 裸露焊盘，8-MLF? 包装:带卷 (TR) 供应商设备封装:8-MLF?（2x2） 产品目录页面:1094 (CN2011-ZH PDF) 其它名称:576-3303-2 |
| LT1766IFE#PBF | 制造商:Linear Technology 功能描述:IC STEP-DOWN REGULATOR 16-TSSOP |
| LT1766IFE#TR | 功能描述:IC REG BUCK ADJ 1.5A 16TSSOP RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 设计资源:Design Support Tool 标准包装:1 系列:- 类型:升压（升压） 输出类型:固定 输出数:1 输出电压:3V 输入电压:0.75 V ~ 2 V PWM 型:- 频率 - 开关:- 电流 - 输出:100mA 同步整流器:是 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:SOT-23-5 细型，TSOT-23-5 包装:剪切带 (CT) 供应商设备封装:TSOT-23-5 其它名称:AS1323-BTTT-30CT |
| LT1766IFE#TRPBF | 功能描述:IC REG BUCK ADJ 1.5A 16TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 设计资源:Design Support Tool 标准包装:1 系列:- 类型:升压（升压） 输出类型:固定 输出数:1 输出电压:3V 输入电压:0.75 V ~ 2 V PWM 型:- 频率 - 开关:- 电流 - 输出:100mA 同步整流器:是 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:SOT-23-5 细型，TSOT-23-5 包装:剪切带 (CT) 供应商设备封装:TSOT-23-5 其它名称:AS1323-BTTT-30CT |
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