参数资料
型号: LTC3419IMS#PBF
厂商: LINEAR TECHNOLOGY CORP
元件分类: 稳压器
英文描述: 1.2 A DUAL SWITCHING CONTROLLER, 2700 kHz SWITCHING FREQ-MAX, PDSO10
封装: LEAD FREE, PLASTIC, MSOP-10
文件页数: 2/16页
文件大小: 266K
代理商: LTC3419IMS#PBF
LTC3419
10
3419fa
deviations do not offer much relief. 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 VIN for high frequency decoupling
when not using an all-ceramic capacitor solution.
Output Capacitor (COUT) Selection
The selection of COUT is driven by the required effective
seriesresistance(ESR).Typically,oncetheESRrequirement
for COUT has been met, the RMS current rating generally
far exceeds the IRIPPLE(P-P) requirement. The output ripple
ΔVOUT is determined by:
ΔΔ
VI ESR
fC
OUT
L
O OUT
≈+
1
8
where fO = operating frequency, COUT = output capacitance
and ΔIL = ripple current in the inductor. For a xed output
voltage, the output ripple is highest at maximum input
voltage since ΔIL increases with input voltage.
Iftantalumcapacitorsareused,itiscriticalthatthecapacitors
are surge tested for use in switching power supplies. An
excellent choice is the AVX TPS series of surface mount
tantalum. These are specially constructed and tested for low
ESR so they give the lowest ESR for a given volume. Other
capacitor types include Sanyo POSCAP, Kemet T510 and
T495 series, and Sprague 593D and 595D series. Consult
the manufacturer for other specic recommendations.
Using Ceramic Input and Output Capacitors
Higher values, lower cost ceramic capacitors are now
becoming available in smaller case sizes. Their high
ripple current, high voltage rating and low ESR make
them ideal for switching regulator applications. Because
the LTC3419 control loop does not depend on the output
capacitor’s ESR for stable operation, ceramic capacitors
can be used freely to achieve very low output ripple and
small circuit size.
However, care must be taken when ceramic capacitors are
used at the input. 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, VIN. 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 VIN, large enough to damage the
part. For more information, see Application Note 88.
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.
Setting the Output Voltage
The LTC3419 regulates the VFB1 and VFB2 pins to 0.6V
during regulation. Thus, the output voltage is set by a
resistive divider according to the following formula:
VV
R
OUT =+
06
1
2
1
2
.( )
Keeping the current small (< 10μA) in these resistors
maximizes efciency, but making it too small may allow
stray capacitance to cause noise problems or reduce the
phase margin of the error amp loop.
To improve the frequency response of the main control
loop, a feedback capacitor (CF) may also be used. Great
care should be taken to route the VFB line away from noise
sources, such as the inductor or the SW line.
Fixed output versions of the LTC3419 (e.g. LTC3419-1)
include an internal resistive divider, eliminating the need
for external resistors. The resistor divider is chosen
such that the VFB input current is approximately 3μA. For
these versions the VFB pin should be connected directly
to VOUT. Table 2 lists the xed output voltages available
for the LTC3419.
APPLICATIONS INFORMATION
Table 2. Fixed Output Voltage Versions
PART NUMBER
VOUT1
VOUT2
LTC3419
Adjustable
LTC3419-1
1.575V
1.8V
相关PDF资料
PDF描述
LM4040C20ILPE3 1-OUTPUT TWO TERM VOLTAGE REFERENCE, 2.048 V, PBCY3
LQS50A48-1V2EK 1-OUTPUT 60 W DC-DC REG PWR SUPPLY MODULE
LQS80A48-1V5REN 1-OUTPUT 120 W DC-DC REG PWR SUPPLY MODULE
LH1601-2R-D5 1-OUTPUT AC-DC REG PWR SUPPLY MODULE
LES020ZG-3N1H 1-OUTPUT 15 W DC-DC REG PWR SUPPLY MODULE
相关代理商/技术参数
参数描述
LTC3421 制造商:LINER 制造商全称:Linear Technology 功能描述:3A, 3MHz Micropower Synchronous Boost Converter with Output Disconnect
LTC3421EUF 功能描述:IC REG BOOST SYNC ADJ 1.5A 24QFN RoHS:否 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
LTC3421EUF#PBF 功能描述:IC REG BOOST SYNC ADJ 1.5A 24QFN 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
LTC3421EUF#TR 功能描述:IC REG BOOST SYNC ADJ 1.5A 24QFN RoHS:否 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
LTC3421EUF#TRPBF 功能描述:IC REG BOOST SYNC ADJ 1.5A 24QFN 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