参数资料
型号: LT1766HFE#TRPBF
厂商: Linear Technology
文件页数: 13/30页
文件大小: 0K
描述: IC REG BUCK ADJ 1.5A 16TSSOP
标准包装: 2,500
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:
工作温度: -40°C ~ 140°C
安装类型: 表面贴装
封装/外壳: 16-TSSOP(0.173",4.40mm)裸露焊盘
包装: 带卷 (TR)
供应商设备封装: 16-TSSOP-EP
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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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
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