- 您现在的位置：买卖IC网 > PDF目录20843 > LTC3214EDD#PBF (Linear Technology)IC LED DRIVR WHITE BCKLGT 10-DFN PDF资料下载
参数资料
| 型号： | LTC3214EDD#PBF |
| 厂商： | Linear Technology |
| 文件页数： | 8/12页 |
| 文件大小： | 0K |
| 描述： | IC LED DRIVR WHITE BCKLGT 10-DFN |
| 标准包装： | 121 |
| 拓扑： | 升压（升压），切换式电容器（充电泵） |
| 输出数： | 1 |
| 内部驱动器： | 是 |
| 类型 - 主要： | 闪灯/白光 |
| 类型 - 次要： | 白色 LED |
| 频率： | 600kHz ~ 1.2MHz |
| 电源电压： | 2.9 V ~ 4.5 V |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 10-WFDFN 裸露焊盘 |
| 供应商设备封装： | 10-DFN（3x3） |
| 包装： | 管件 |
| 工作温度： | -40°C ~ 85°C |
| 产品目录页面： | 1339 (CN2011-ZH PDF) |
LTC3214
APPLICATIONS INFORMATION
V IN , CPO Capacitor Selection
The value and type of capacitors used with the LTC3214
determine several important parameters such as regulator
control loop stability, output ripple, charge pump strength
and minimum start-up time.
To reduce noise and ripple, it is recommended that low
equivalent series resistance (ESR) ceramic capacitors be
used for both C VIN and C CPO . Tantalum and aluminum ca-
pacitors are not recommended because of their high ESR.
The value of C CPO directly controls the amount of output
ripple for a given load current. Increasing the size of C CPO
will reduce the output ripple at the expense of higher start-
perturbation on the input power supply line. Note that a
higher ESR capacitor such as tantalum will have higher
input noise due to the input current change times the ESR.
Therefore, ceramic capacitors are again recommended for
their exceptional ESR performance. Input noise can be
further reduced by powering the LTC3214 through a very
small series inductor as shown in Figure 3. A 10nH induc-
tor will reject the fast current notches, thereby presenting
a nearly constant current load to the input power supply.
For economy, the 10nH inductor can be fabricated on the
PC board with about 1cm (0.4") of PC board trace.
10nH
V IN
up current. The peak-to-peak output ripple for 1.5x mode
0.1μF
2.2μF
LTC3214
is approximately given by the expression:
V RIPPLE(P-P) = I OUT /(3f OSC ? C CPO )
where f OSC is the LTC3214’s oscillator frequency (typically
900kHz) and C CPO is the output storage capacitor.
Both the style and value of the output capacitor can sig-
ni?cantly affect the stability of the LTC3214. As shown in
the Block Diagram, the LTC3214 uses a control loop to
adjust the strength of the charge pump to match the cur-
rent required at the output. The error signal of this loop
is stored directly on the output charge storage capacitor.
The charge storage capacitor also serves as the dominant
pole for the control loop. To prevent ringing or instability,
it is important for the output capacitor to maintain at least
3μF of actual capacitance over all conditions.
Likewise, excessive ESR on the output capacitor will tend
to degrade the loop stability of the LTC3214. To prevent
poor load transient response and instability, the ESR of the
output capacitor should be kept below 50mΩ. Multilayer
ceramic chip capacitors typically have exceptional ESR
performance. MLCCs combined with a tight board layout
will yield very good stability. As the value of C CPO controls
the amount of output ripple, the value of C VIN controls the
amount of ripple present at the input pin (V IN ). The input
current to the LTC3214 will be relatively constant while
the charge pump is on either the input charging phase or
the output charging phase but will drop to zero during the
clock nonoverlap times. Since the nonoverlap time is small
(~15ns), these missing “notches” will result in only a small
GND
3214 F03
Figure 3. 10nH Inductor Used for Input Noise Reduction
(Approximately 1cm of Wire)
Flying Capacitor Selection
Warning: Polarized capacitors such as tantalum or
aluminum should never be used for the ?ying capaci-
tors since their voltage can reverse upon start-up of the
LTC3214. Ceramic capacitors should always be used for
the ?ying capacitors.
The ?ying capacitors control the strength of the charge
pump. In order to achieve the rated output current it is
necessary to have at least 1.6μF of actual capacitance
for each of the ?ying capacitors. Capacitors of different
materials lose their capacitance with higher temperature
and voltage at different rates. For example, a ceramic
capacitor made of X7R material will retain most of its
capacitance from –40°C to 85°C whereas a Z5U or Y5V
style capacitor will lose considerable capacitance over
that range. Z5U and Y5V capacitors may also have a very
poor voltage coef?cient causing them to lose 60% or more
of their capacitance when the rated voltage is applied.
Therefore, when comparing different capacitors, it is often
more appropriate to compare the amount of achievable
capacitance for a given case size rather than comparing
the speci?ed capacitance value. For example, over rated
voltage and temperature conditions, a 1μF, 10V, Y5V
3214fb
8
相关PDF资料 |
PDF描述 |
|---|---|
| REC3-1209SRW/H2/A/M/SMD | CONV DC/DC 3W 9-18VIN 09VOUT |
| REC3-1212DRW/H2/C/M | CONV DC/DC 3W 9-18VIN +/-12VOUT |
| P51-1000-S-O-I12-4.5V-000-000 | SENS 1000PSI 7/16-20 UNF 2B 4.5V |
| REC5-4809DRW/H6/C/M | CONV DC/DC 5W 36-72VIN +/-09VOUT |
| P51-300-S-C-P-4.5OVP-000-000 | SENSOR 300PSI M12-1.5 6G .5-4.5V |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3215 | 制造商:LINER 制造商全称:Linear Technology 功能描述:700mA Low Noise High Current LED Charge Pump |
| LTC3215EDD | 功能描述:IC LED DRIVR WHITE BCKLGT 10-DFN RoHS:否 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 标准包装:6,000 系列:- 恒定电流:- 恒定电压:- 拓扑:开路漏极，PWM 输出数:4 内部驱动器:是 类型 - 主要:LED 闪烁器 类型 - 次要:- 频率:400kHz 电源电压:2.3 V ~ 5.5 V 输出电压:- 安装类型:表面贴装 封装/外壳:8-VFDFN 裸露焊盘 供应商设备封装:8-HVSON 包装:带卷 (TR) 工作温度:-40°C ~ 85°C 其它名称:935286881118PCA9553TK/02-TPCA9553TK/02-T-ND |
| LTC3215EDD#PBF | 功能描述:IC LED DRIVR WHITE BCKLGT 10-DFN RoHS:是 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 标准包装:60 系列:- 恒定电流:- 恒定电压:- 拓扑:线性（LDO），PWM，升压（升压） 输出数:8 内部驱动器:是 类型 - 主要:背光 类型 - 次要:RGB，白色 LED 频率:500kHz ~ 1.5MHz 电源电压:4.75 V ~ 26 V 输出电压:45V 安装类型:* 封装/外壳:* 供应商设备封装:* 包装:* 工作温度:-40°C ~ 85°C |
| LTC3215EDD#TR | 功能描述:IC LED DRIVR WHITE BCKLGT 10-DFN RoHS:否 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 标准包装:6,000 系列:- 恒定电流:- 恒定电压:- 拓扑:开路漏极，PWM 输出数:4 内部驱动器:是 类型 - 主要:LED 闪烁器 类型 - 次要:- 频率:400kHz 电源电压:2.3 V ~ 5.5 V 输出电压:- 安装类型:表面贴装 封装/外壳:8-VFDFN 裸露焊盘 供应商设备封装:8-HVSON 包装:带卷 (TR) 工作温度:-40°C ~ 85°C 其它名称:935286881118PCA9553TK/02-TPCA9553TK/02-T-ND |
| LTC3215EDD#TRPBF | 功能描述:IC LED DRIVR WHITE BCKLGT 10-DFN RoHS:是 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 标准包装:6,000 系列:- 恒定电流:- 恒定电压:- 拓扑:开路漏极，PWM 输出数:4 内部驱动器:是 类型 - 主要:LED 闪烁器 类型 - 次要:- 频率:400kHz 电源电压:2.3 V ~ 5.5 V 输出电压:- 安装类型:表面贴装 封装/外壳:8-VFDFN 裸露焊盘 供应商设备封装:8-HVSON 包装:带卷 (TR) 工作温度:-40°C ~ 85°C 其它名称:935286881118PCA9553TK/02-TPCA9553TK/02-T-ND |
发布紧急采购，3分钟左右您将得到回复。