参数资料
型号: LTC3520EUF#PBF
厂商: Linear Technology
文件页数: 17/24页
文件大小: 0K
描述: IC REG BUCK BOOST SYNC ADJ 24QFN
标准包装: 91
类型: 降压(降压),升压(升压)
输出类型: 可调式
输出数: 2
输出电压: 0.8 V ~ 5.5 V
输入电压: 2.2 V ~ 5.5 V
PWM 型: 电流模式,混合
频率 - 开关: 100kHz ~ 2MHz
电流 - 输出: 600mA,1A
同步整流器:
工作温度: -40°C ~ 85°C
安装类型: 表面贴装
封装/外壳: 24-WFQFN 裸露焊盘
包装: 管件
供应商设备封装: 24-QFN 裸露焊盘(4x4)
产品目录页面: 1334 (CN2011-ZH PDF)
LTC3520
APPLICATIONS INFORMATION
Δ V P ? P , BOOST =
Δ V P ? P , B U CK =
In addition to affecting output current ripple, the size of
the inductor can also affect the stability of the feedback
loop. In boost mode, the converter transfer function has
a right half plane zero at a frequency that is inversely
proportional to the value of the inductor. As a result, a
large inductor can move this zero to a frequency that is
low enough to degrade the phase margin of the feedback
loop. It is recommended that the inductor value be chosen
less than 10μH if the buck-boost converter is to be used
in the boost region.
Buck-Boost Output Capacitor Selection
A low ESR output capacitor should be utilized at the buck-
boost converter output in order to minimize output volt-
age ripple. Multilayer ceramic capacitors are an excellent
choice as they have low ESR and are available in small
footprints. The capacitor should be chosen large enough
to reduce the output voltage ripple to acceptable levels.
Neglecting the capacitor ESR and ESL, the peak-to-peak
output voltage ripple can be calculated by the following
formulas, where f is the frequency in MHz, C OUT is the
capacitance in μF, L is the inductance in μH, and I LOAD is
the output current in amps.
I LOAD ( V OUT ? V IN )
C OUT V OUT f
1 ( V IN ? V OUT ) V OUT
8 LC OUT f 2 V IN
capacitor is too small, the bandwidth of the converter
will extend high enough to degrade the phase margin.
To prevent this from happening, it is recommended that
a minimum value of 22μF be used for the buck-boost
output capacitor.
Buck-Boost Input Capacitor Selection
The supply current to the buck-boost converter is provided
by the PV IN1 and PV IN3 pins. It is recommended that a
low ESR ceramic capacitor with a value of at least 22μF
be located as close to this pin as possible.
Inductor Style and Core Material
Different inductor core materials and styles have an
impact on the size and price of an inductor at any given
peak current rating. Toroid or shielded pot cores in ferrite
or permalloy materials are small and reduce emissions,
but generally cost more than powdered iron core induc-
tors with similar electrical characteristics. The choice of
inductor style depends upon the price, sizing, and EMI
requirements of a particular application. However, the
inductor must also have low ESR to provide acceptable
ef?ciency and must be able to carry the highest current
required by the application without saturating. Table 3
provides a list of several manufacturers of inductors that
are well suited to LTC3520 applications.
Table 3. Inductor Vendor Information
MANUFACTURER PHONE WEB SITE
Since the output current is discontinuous in boost mode,
the ripple in this mode will generally be much larger than
the magnitude of the ripple in buck mode. In addition to
controlling the ripple magnitude, the value of the output
capacitor also affects the location of the resonant frequency
Coilcraft
Murata
Sumida
TDK
TOKO
847-639-6400
814-238-0490
847-956-0702
847-803-6296
847-699-7864
www.coilcraft.com
www.murata.com
www.sumida.com
www.component.tdk.com
www.tokoam.com
in the open loop converter transfer function. If the output
3520fa
17
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LTC3520EUF-TRPBF 制造商:LINER 制造商全称:Linear Technology 功能描述:Synchronous 1A Buck-Boost and 600mA Buck Converters
LTC3520IUF#PBF 功能描述:IC REG BUCK BOOST SYNC ADJ 24QFN 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
LTC3520IUF#TRPBF 功能描述:IC REG BUCK BOOST SYNC ADJ 24QFN 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
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LTC3521EFE#PBF 功能描述:IC REG BUCK BST SYNC ADJ 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