- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄377775 > LTC3411EMS (LINEAR TECHNOLOGY CORP) 1.25A, 4MHz, Synchronous Step-Down DC/DC Converter PDF資料下載
參數(shù)資料
| 型號： | LTC3411EMS |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | 1.25A, 4MHz, Synchronous Step-Down DC/DC Converter |
| 中文描述： | 2 A SWITCHING REGULATOR, 4000 kHz SWITCHING FREQ-MAX, PDSO10 |
| 封裝： | PLASTIC, MSOP-10 |
| 文件頁數(shù)： | 10/20頁 |
| 文件大?。?/td> | 288K |
| 代理商： | LTC3411EMS |
LTC3411
10
sn3411 3411fs
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. Alumi-
num electrolytic, special polymer, ceramic and dry tantulum
capacitors are all available in surface mount packages.
The OS-CON semiconductor dielectric capacitor available
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 mount tantalums, avalable in case heights rang-
ing from 2mm to 4mm. Aluminum electrolytic capacitors
have a significantly larger ESR, and is often used in
extremely cost-sensitive applications provided that con-
sideration is given to ripple current ratings and long term
reliability. Ceramic capacitors have the lowest ESR and
cost but also have the lowest capacitance density, a high
voltage and temperature coefficient and exhibit audible
piezoelectric effects. In addition, the high Q of ceramic
capacitors along with trace inductance can lead to signifi-
cant ringing. Other capacitor types include the Panasonic
specialty polymer (SP) capacitors.
In most cases, 0.1
μ
F to 1
μ
F of ceramic capacitors should
also be placed close to the LTC3411 in parallel with the
main capacitors for high frequency decoupling.
Ceramic Input and Output Capacitors
Higher value, lower cost ceramic capacitors are now
becoming available in smaller case sizes. These are tempt-
ing for switching regulator use because of their very low
ESR. Unfortunately, the ESR is so low that it can cause
loop stability problems. Solid tantalum capacitor ESR
generates a loop “zero” at 5kHz to 50kHz that is instrumen-
tal in giving acceptable loop phase margin. Ceramic ca-
pacitors remain capacitive to beyond 300kHz and ususally
resonate with their ESL before ESR becomes effective.
Also, ceramic caps are prone to temperature effects which
requires the designer to check loop stability over the
operating temperature range. To minimize their large
temperature and voltage coefficients, only X5R or X7R
ceramic capacitors should be used. A good selection of
ceramic capacitors is available from Taiyo Yuden, TDK and
Murata.
Great care must be taken when using only ceramic input
and output capacitors. When a ceramic capacitor is used
at the input and the power is being supplied through long
wires, such as from a wall adapter, a load step at the output
can induce ringing at the V
IN
pin. At best, this ringing can
couple to the output and be mistaken as loop instability. At
worst, the ringing at the input can be large enough to
damage the part.
Since the ESR of a ceramic capacitor is so low, the input
and output capacitor must instead fulfill a charge storage
requirement. During a load step, the output capacitor must
instantaneously supply the current to support the load
until the feedback loop raises the switch current enough to
support the load. The time required for the feedback loop
to respond is dependent on the compensation compo-
nents and the output capacitor size. Typically, 3 to 4 cycles
are required to respond to a load step, but only in the first
cycle does the output drop linearly. The output droop,
V
DROOP
, is usually about 2 to 3 times the linear drop of the
first cycle. Thus, a good place to start is with the output
capacitor size of approximately:
C
I
f
V
OUT
OUT
DROOP
O
≈
2 5
More capacitance may be required depending on the duty
cycle and load step requirements.
In most applications, the input capacitor is merely re-
quired to supply high frequency bypassing, since the
impedance to the supply is very low. A 10
μ
F ceramic
capacitor is usually enough for these conditions.
APPLICATIU
W
U
U
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LTC3411 | 1.25A, 4MHz, Synchronous Step-Down DC/DC Converter |
| LTC3411EDD | 1.25A, 4MHz, Synchronous Step-Down DC/DC Converter |
| LTC3413 | 3A, 2MHz Monolithic Synchronous Regulator for DDR/QDR Memory Termination |
| LTC3413EFE | 3A, 2MHz Monolithic Synchronous Regulator for DDR/QDR Memory Termination |
| LTC3423 | Low Output Voltage 3MHz Micropower Synchronous Boost Converters |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LTC3411EMS#PBF | 功能描述:IC REG BUCK SYNC ADJ 10MSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關(guān)穩(wěn)壓器 系列:- 標(biāo)準(zhǔn)包裝:250 系列:- 類型:降壓（降壓） 輸出類型:固定 輸出數(shù):1 輸出電壓:1.2V 輸入電壓:2.05 V ~ 6 V PWM 型:電壓模式 頻率 - 開關(guān):2MHz 電流 - 輸出:500mA 同步整流器:是 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:6-UFDFN 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:6-SON（1.45x1） 產(chǎn)品目錄頁面:1032 (CN2011-ZH PDF) 其它名稱:296-25628-2 |
| LTC3411EMS#PBFTR | 制造商:Linear Technology 功能描述:Conv DC-DC Single Step Down 2.63V to 5.5V 10-Pin MSOP T/R |
| LTC3411EMS#TR | 功能描述:IC REG BUCK SYNC ADJ 10MSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關(guān)穩(wěn)壓器 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- 類型:降壓（降壓） 輸出類型:固定 輸出數(shù):1 輸出電壓:1.2V，1.5V，1.8V，2.5V 輸入電壓:2.7 V ~ 20 V PWM 型:- 頻率 - 開關(guān):- 電流 - 輸出:50mA 同步整流器:是 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:10-TFSOP，10-MSOP（0.118"，3.00mm 寬）裸露焊盤 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:10-MSOP 裸露焊盤 |
| LTC3411EMS#TRPBF | 功能描述:IC REG BUCK SYNC ADJ 10MSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關(guān)穩(wěn)壓器 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- 類型:降壓（降壓） 輸出類型:固定 輸出數(shù):1 輸出電壓:1.2V，1.5V，1.8V，2.5V 輸入電壓:2.7 V ~ 20 V PWM 型:- 頻率 - 開關(guān):- 電流 - 輸出:50mA 同步整流器:是 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:10-TFSOP，10-MSOP（0.118"，3.00mm 寬）裸露焊盤 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:10-MSOP 裸露焊盤 |
| LTC3411EMSPBF | 制造商:Linear Technology 功能描述:LTC3411 adj 1.5A sync SD dc-dc converter |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。