参数资料
型号: LTC3417AIFE-2#TRPBF
厂商: Linear Technology
文件页数: 11/20页
文件大小: 0K
描述: IC REG BUCK SYNC ADJ DL 20TSSOP
标准包装: 2,500
类型: 降压(降压)
输出类型: 可调式
输出数: 2
输出电压: 0.8 V ~ 5 V
输入电压: 2.25 V ~ 5.5 V
PWM 型: 电流模式,混合
频率 - 开关: 1.5MHz,600kHz ~ 4MHz
电流 - 输出: 1A,1.5A
同步整流器:
工作温度: -40°C ~ 125°C
安装类型: 表面贴装
封装/外壳: 20-TSSOP(0.173",4.40mm 宽)裸露焊盘
包装: 带卷 (TR)
供应商设备封装: 20-TSSOP-EP
LTC3417A-2
APPLICATIONS INFORMATION
When D1 = D2 then the equation simpli?es to:
I RMS = ( I 1 + I 2 ) D ( 1– D )
or
Output Capacitor (C OUT1 and C OUT2 ) Selection
The selection of C OUT1 and C OUT2 is driven by the required
ESR to minimize voltage ripple and load step transients.
Typically, once the ESR requirement is satis?ed, the
capacitance is adequate for ?ltering. The output ripple
V OUT ( V IN – V OUT )
I RMS = ( I 1 + I 2 )
V IN
where the maximum average output currents I 1 and I 2
( Δ V OUT ) is determined by:
V OUT I L ESR COUT +
1
8 ? f O ? C OUT
I 1 = I LIM1 –
Δ I L2
I 2 = I LIM2 –
equal the respective peak currents minus half the peak-
to-peak ripple currents:
Δ I L1
2
2
These formula have a maximum at V IN = 2V OUT , where
I RMS = (I 1 + I 2 )/2. This simple worst case is commonly
used to determine the highest I RMS .
For “out of phase” operation, the ripple current can be
lower than the “in phase” current.
In the “out of phase” case, the maximum I RMS does not
occur when V OUT1 = V OUT2 . The maximum typically oc-
curs when V OUT1 – V IN /2 = V OUT2 or when V OUT2 – V IN /2
= V OUT1 . As a good rule of thumb, the amount of worst
case ripple is about 75% of the worst case ripple in the
“in phase” mode. Also note that when V OUT1 = V OUT2 =
V IN /2 and I 1 = I 2 , the ripple is zero.
Note that capacitor manufacturer’s ripple current ratings
are often based on only 2000 hours lifetime. This makes
it advisable to further derate the capacitor, or choose a
capacitor rated at a higher temperature than required.
Several capacitors may also be paralleled to meet the
size or height requirements of the design. An additional
0.1μF to 1μF ceramic capacitor is also recommended on
V IN for high frequency decoupling, when not using an all
ceramic capacitor solution.
where f O = operating frequency, C OUT = output capacitance
and Δ I L = ripple current in the inductor. The output ripple
is highest at maximum input voltage, since Δ I L increases
with input voltage. With Δ I L = 0.35I LOAD(MAX) , the output
ripple will be less than 100mV at maximum V IN and f O =
1MHz with:
ESR COUT < 150mΩ
Once the ESR requirements for C OUT have been met, the
RMS current rating generally far exceeds the I RIPPLE(P-P)
requirement, except for an all ceramic solution.
In surface mount applications, multiple capacitors may
have to be paralleled to meet the capacitance, ESR or RMS
current handling requirement of the application. Aluminum
electrolytic, special polymer, ceramic and dry tantalum
capacitors are all available in surface mount packages.
The OS-CON semiconductor dielectric capacitor avail-
able from Sanyo has the lowest ESR(size) product of any
aluminum electrolytic at a somewhat higher price. Special
polymer capacitors, such as Sanyo POSCAP, offer very
low ESR, but have a lower capacitance density than other
types. Tantalum capacitors have the highest capacitance
density, but it has a larger ESR and it is critical that the
capacitors are surge tested for use in switching power
supplies. An excellent choice is the AVX TPS series of
surface tantalums, available in case heights ranging from
2mm to 4mm. Aluminum electrolytic capacitors have a
signi?cantly larger ESR, and are often used in extremely
cost-sensitive applications provided that consideration
3417a2fa
11
相关PDF资料
PDF描述
LTC3417EDHC#PBF IC REG BUCK SYNC ADJ DL 16DFN
LTC3418EUHF#TRPBF IC REG BUCK SYNC ADJ 8A 38QFN
LTC3419IMS-1#TRPBF IC REG BUCK SYNC ADJ 0.6A 10MSOP
LTC3421EUF#TRPBF IC REG BOOST SYNC ADJ 1.5A 24QFN
LTC3422EDD#TRPBF IC REG BOOST SYNC ADJ 1.5A 10DFN
相关代理商/技术参数
参数描述
LTC3417AIFEPBF 制造商:Linear Technology 功能描述:Conv DC-DC Dual Step-Down 5.5V TSSOP20EP
LTC3417EDHC 制造商:Linear Technology 功能描述:Conv DC-DC Dual Step Down 2.25V to 5.5V 16-Pin DFN EP
LTC3417EDHC#PBF 功能描述:IC REG BUCK SYNC ADJ DL 16DFN 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
LTC3417EDHC#TRPBF 功能描述:IC REG BUCK SYNC ADJ DL 16DFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 标准包装:2,500 系列:- 类型:降压(降压) 输出类型:固定 输出数:1 输出电压:1.2V,1.5V,1.8V,2.5V 输入电压:2.7 V ~ 20 V PWM 型:- 频率 - 开关:- 电流 - 输出:50mA 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:10-TFSOP,10-MSOP(0.118",3.00mm 宽)裸露焊盘 包装:带卷 (TR) 供应商设备封装:10-MSOP 裸露焊盘
LTC3417EFE 制造商:Linear Technology 功能描述:Conv DC-DC Dual Step Down 2.25V to 5.5V 20-Pin TSSOP EP