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| 型号： | LTC3414EFE#PBF |
| 厂商： | Linear Technology |
| 文件页数： | 9/16页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK SYNC ADJ 4A 20TSSOP |
| 标准包装： | 74 |
| 类型： | 降压（降压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 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： | 1MHz |
| 电流 - 输出： | 4A |
| 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： | 20-TSSOP（0.173"，4.40mm 宽）裸露焊盘 |
| 包装： | 管件 |
| 供应商设备封装： | 20-TSSOP-EP |
| 产品目录页面： | 1334 (CN2011-ZH PDF) |
LTC3414
APPLICATIO S I FOR ATIO
C IN and C OUT Selection
The input capacitance, C IN , is needed to filter the trapezoi-
dal wave current at the source of the top MOSFET. To
prevent large voltage transients from occurring, a low ESR
input capacitor sized for the maximum RMS current
should be used. The maximum RMS current is given by:
applications provided that consideration is given to ripple
current ratings and long term reliability. Ceramic capaci-
tors have excellent low ESR characteristics but can have a
high voltage coefficient and audible piezoelectric effects.
The high Q of ceramic capacitors with trace inductance
can also lead to significant ringing.
= I OUT ( MAX ) OUT
I RMS
V
V IN
V IN
V OUT
–1
Using Ceramic Input and Output Capacitors
Higher values, lower cost ceramic capacitors are now
becoming available in smaller case sizes. Their high ripple
8 fC OUT ? ?
V OUT = 0 . 8 V ? 1 +
?
This formula has a maximum at V IN = 2V OUT , where
I RMS = I OUT/2 . This simple worst-case condition is com-
monly used for design because even significant deviations
do not offer much relief. Note that ripple current ratings
from capacitor manufacturers are often based on only
2000 hours of life which 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 size or height requirements in
the design. For low input voltage applications, sufficient
bulk input capacitance is needed to minimize transient
effects during output load changes.
The selection of C OUT is determined by the effective series
resistance (ESR) that is required to minimize voltage
ripple and load step transients as well as the amount of
bulk capacitance that is necessary to ensure that the
control loop is stable. Loop stability can be checked by
viewing the load transient response as described in a later
section. The output ripple, Δ V OUT , is determined by:
? 1 ?
Δ V OUT ≤ Δ I L ? ESR +
?
The output ripple is highest at maximum input voltage
since Δ I L increases with input voltage. Multiple capacitors
placed in parallel may be needed to meet the ESR and RMS
current handling requirements. Dry tantalum, special poly-
mer, aluminum electrolytic, and ceramic capacitors are all
available in surface mount packages. Special polymer
current, high voltage rating and low ESR make them ideal
for switching regulator applications. However, care must
be taken when these capacitors are used at the input and
output. When a ceramic capacitor is used at the input and
the power is supplied by a wall adapter through long wires,
a load step at the output can induce ringing at the input,
V IN . At best, this ringing can couple to the output and be
mistaken as loop instability. At worst, a sudden inrush of
current through the long wires can potentially cause a
voltage spike at V IN large enough to damage the part.
When choosing the input and output ceramic capacitors,
choose the X5R or X7R dielectric formulations. These
dielectrics have the best temperature and voltage charac-
teristics of all the ceramics for a given value and size.
Output Voltage Programming
The output voltage is set by an external resistive divider
according to the following equation:
? R 2 ?
? R 1 ?
The resistive divider allows pin V FB to sense a fraction of
the output voltage as shown in Figure 2.
V OUT
R2
V FB
capacitors offer very low ESR but have lower capacitance
density than other types. Tantalum capacitors have the
highest capacitance density but it is important to only use
types that have been surge tested for use in switching
LTC3414
SGND
R1
3414 F02
power supplies. Aluminum electrolytic capacitors have
Figure 2. Setting the Output Voltage
significantly higher ESR, but can be used in cost-sensitive
3414fb
9
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相关代理商/技术参数 |
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| LTC3414IFE | 制造商:Linear Technology 功能描述:Conv DC-DC Single Step Down 2.25V to 5.5V 20-Pin TSSOP EP |
| LTC3414IFE N57875 | 制造商: 功能描述: 制造商:undefined 功能描述: |
| LTC3414IFE#PBF | 功能描述:IC REG BUCK SYNC ADJ 4A 20TSSOP 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:250 系列:- 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:1.2V 输入电压:2.05 V ~ 6 V PWM 型:电压模式 频率 - 开关:2MHz 电流 - 输出:500mA 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:6-UFDFN 包装:带卷 (TR) 供应商设备封装:6-SON（1.45x1） 产品目录页面:1032 (CN2011-ZH PDF) 其它名称:296-25628-2 |
| LTC3414IFE#PBF | 制造商:Linear Technology 功能描述:IC SYNC STEP-DOWN REGULATOR 20-TSSOP 制造商:Linear Technology 功能描述:IC, SYNC STEP-DOWN REGULATOR, 20-TSSOP |
| LTC3414IFE#TR | 制造商:Linear Technology 功能描述:DP-SWREG/Monolithic, 4MHz, 4A Synch Step-dwn Regulator I Grade |
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