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参数资料
| 型号： | LTC3202EMS#PBF |
| 厂商： | Linear Technology |
| 文件页数： | 9/12页 |
| 文件大小： | 0K |
| 描述： | IC LED DRVR WHITE BCKLGT 10-MSOP |
| 标准包装： | 50 |
| 拓扑： | PWM，切换式电容器（充电泵） |
| 输出数： | 1 |
| 内部驱动器： | 是 |
| 类型 - 主要： | 背光 |
| 类型 - 次要： | 白色 LED |
| 频率： | 1.5MHz |
| 电源电压： | 2.7 V ~ 4.5 V |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 10-TFSOP，10-MSOP（0.118"，3.00mm 宽） |
| 供应商设备封装： | 10-MSOP |
| 包装： | 管件 |
| 工作温度： | -40°C ~ 85°C |
LTC3202
OPERATIO
10nH
4
V IN
Table 2 Recommended Capacitor Vendors
AVX www.avxcorp.com
V IN
0.1 μ F
1 μ F
5, 11
LTC3202
GND
Kemet
Murata
www.kemet.com
www.murata.com
3202 F05
Taiyo Yuden
Vishay
www.t-yuden.com
www.vishay.com
Figure 5. 10nH Inductor Used for Input Noise Reduction
Flying Capacitor Selection
Warning: A polarized capacitor such as tantalum or alumi-
For very light load applications the flying capacitor may be
reduced to save space or cost. The theoretical minimum
output resistance of a 2:3 fractional charge pump is given
by:
num should never be used for the flying capacitors since
their voltage can reverse upon start-up of the LTC3202.
Ceramic capacitors should always be used for the flying
R OL ( MIN ) ≡
1 . 5 V IN – V OUT
I OUT
=
1
2 f 0 SC C FLY
capacitors.
η IDEAL ≡ = = V OUT
P IN
1 . 5 V IN
The flying capacitor controls the strength of the charge
pump. In order to achieve the rated output current it is
necessary to have at least 0.7 μ F of capacitance for each of
the flying 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 capaci-
tance over that range. Z5U and Y5V capacitors may also
have a very poor voltage coefficient causing them to lose
60% or more of their capacitance when the rated voltage
is applied. Therefore, when comparing different capaci-
tors it is often more appropriate to compare the amount of
achievable capacitance for a given case size rather than
comparing the specified capacitance value. For example,
over rated voltage and temperature conditions, a 1 μ F, 10V,
Y5V ceramic capacitor in a 0603 case may not provide any
more capacitance than a 0.22 μ F, 10V, X7R available in the
same 0603 case. The capacitor manufacturer’s data sheet
should be consulted to determine what value of capacitor
is needed to ensure minimum capacitances at all tempera-
tures and voltages.
Table 2 shows a list of ceramic capacitor manufacturers
Where f OSC is the switching frequency (1.5MHz typ) and
C FLY is the value of the flying capacitors. Note that the
charge pump will typically be weaker than the theoretical
limit due to additional switch resistance, however for very
light load applications the above expression can be used
as a guideline in determining a starting capacitor value.
Power Efficiency
The power efficiency ( η ) of the LTC3202 is similar to that
of a linear regulator with an effective input voltage of 1.5
times the actual input voltage. This occurs because the
input current for a 2:3 fractional charge pump is approxi-
mately 1.5 times the load current. In an ideal regulating 2:3
charge pump the power efficiency would be given by:
P OUT V OUT ? I OUT
3
V IN ? I OUT
2
At moderate to high output power the switching losses
and quiescent current of the LTC3202 are negligible and
the expression above is valid. For example with V IN = 3.2V,
I OUT = 80mA and V OUT regulating to 4.2V the measured
efficiency is 82% which is just under the theoretical 87.5%
calculation.
and how to contact them:
3202fa
9
相关PDF资料 |
PDF描述 |
|---|---|
| LTC3202EMS | IC LED DRVR WHITE BCKLGT 10-MSOP |
| LTC3201EMS#PBF | IC LED DRVR WHITE BCKLGT 10-MSOP |
| VLCF4020T-6R8N1R0 | INDUCTOR POWER 6.8UH 1.0A SMD |
| P51-3000-S-M-I12-4.5V-000-000 | SENSOR 3000PSI M10-1.0 6G 4.5V |
| REC5-2409SRW/H2/C/M/SMD-R | CONV DC/DC 5W 18-36VIN 09VOUT |
相关代理商/技术参数 |
参数描述 |
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| LTC3203 | 制造商:LINER 制造商全称:Linear Technology 功能描述:500mA Output Current Low Noise Dual Mode Step-Up Charge Pumps |
| LTC3203-1 | 制造商:LINER 制造商全称:Linear Technology 功能描述:500mA Output Current Low Noise Dual Mode Step-Up Charge Pumps |
| LTC3203B | 制造商:LINER 制造商全称:Linear Technology 功能描述:500mA Output Current Low Noise Dual Mode Step-Up Charge Pumps |
| LTC3203B-1 | 制造商:LINER 制造商全称:Linear Technology 功能描述:500mA Output Current Low Noise Dual Mode Step-Up Charge Pumps |
| LTC3203BEDD | 制造商:LINER 制造商全称:Linear Technology 功能描述:500mA Output Current Low Noise Dual Mode Step-Up Charge Pumps |
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