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参数资料
| 型号： | LT1766IGN#PBF |
| 厂商： | Linear Technology |
| 文件页数： | 13/30页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK ADJ 1.5A 16SSOP |
| 标准包装： | 100 |
| 类型： | 降压（降压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 1.2 V ~ 54 V |
| 输入电压： | 5.5 V ~ 60 V |
| PWM 型： | 电流模式 |
| 频率 - 开关： | 200kHz |
| 电流 - 输出： | 1.5A |
| 同步整流器： | 无 |
| 工作温度： | -40°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 16-SSOP（0.154"，3.90mm 宽） |
| 包装： | 管件 |
| 供应商设备封装： | 16-SSOP |
| 产品目录页面： | 1329 (CN2011-ZH PDF) |
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LT1766/LT1766-5
APPLICATIONS INFORMATION
the high side for discontinuous mode, so it can be used
for all conditions.
Maximum load current would be equal to maximum switch
current for an in?nitely large inductor, but with ?nite
)( )
( )( )( )( )
I PEAK = I OUT +
(I LP - P )
2
= I OUT +
(
V OUT V IN – V OUT
2 V IN f L
inductor size, maximum load current is reduced by one-
half peak-to-peak inductor current (I LP-P ). The following
formula assumes continuous mode operation, implying
that the term on the right is less than one-half of I P .
( V OUT + V F ) ( V IN ? V OUT V F )
I P – LP-P = I P ?
2 ( )( )( V IN )
( 5 + 0 . 63 ) ( 8 ? 5 – 0 . 63 )
(
)(
)
2 20 ? 10 200 ? 10 3 ( 8 )
( 5 + 0 . 63 ) ( 15 ? 5 – 0 . 63 )
2 ( )( ) ( 15 )
I OUT ( MAX ) = 1 . 5 ?
20 ? 10 200 ? 10 3
EMI
Decide if the design can tolerate an open core geometry like
a rod or barrel, which have high magnetic ?eld 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 ?eld
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 ?nal choice. They have
experience with a wide range of inductor types and can tell
you about the latest developments in low pro?le, surface
mounting, etc.
Maximum Output Load Current
Maximum load current for a buck converter is limited
I OUT(MAX) =
Continuous Mode
I –
2 L f
For V OUT = 5V, V IN = 8V, V F(D1) = 0.63V, f = 200kHz and
L = 20μH:
I OUT ( MAX ) = 1 . 5 ? ? 6
= 1 . 5 ? 0 . 21 = 1 . 29 A
Note that there is less load current available at the higher
input voltage because inductor ripple current increases.
At V IN = 15V, duty cycle is 33% and for the same set of
conditions:
? 6
= 1 . 5 ? 0 . 44 = 1 . 06 A
To calculate actual peak switch current with a given set
( V OUT + V F ) ( V IN ? V OUT F )
2 ( )( )( V IN )
by the maximum switch current rating (I P ). The current
rating for the LT1766 is 1.5A. Unlike most current mode
converters, 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
compensation required to prevent subharmonic oscilla-
of conditions, use:
I SW ( PEAK ) = I OUT +
= I OUT +
I LP -P
2
L f
– V
tions in current mode converters. (For detailed analysis,
see Application 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.
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 de?ned later
in this section.
*Patent # 6, 498, 466
1766fc
13
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LT1766IGN-TR | 制造商:LINER 制造商全称:Linear Technology 功能描述:5.5V to 60V 1.5A, 200kHz Step-Down Switching Regulator |
| LT1766IGN-TRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:5.5V to 60V 1.5A, 200kHz Step-Down Switching Regulator |
| LT1767 | 制造商:LINER 制造商全称:Linear Technology 功能描述:1.4A, 500kHz Step-Down Switching Regulator |
| LT1767-1.8 | 制造商:LINER 制造商全称:Linear Technology 功能描述:Monolithic 1.5A, 1.25MHz Step-Down Switching Regulators |
| LT1767-2.5 | 制造商:LINER 制造商全称:Linear Technology 功能描述:Monolithic 1.5A, 1.25MHz Step-Down Switching Regulators |
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