- 您现在的位置：买卖IC网 > PDF目录20847 > LTC3202EMS (Linear Technology)IC LED DRVR WHITE BCKLGT 10-MSOP PDF资料下载
参数资料
| 型号： | LTC3202EMS |
| 厂商： | Linear Technology |
| 文件页数： | 8/12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
R OL is dependent on a number of factors including the
switching term, 1/(2f OSC C FLY ), internal switch resis-
tances and the nonoverlap period of the switching circuit.
However, for a given R OL , the amount of current available
will be directly proportional to the advantage voltage
1.5V IN – V OUT . This voltage can typically be quite small.
Consider the example of driving white LEDs from a
3.1V supply. If the LED forward voltage is 3.8V and the
0.6V V FB setting is used, the advantage voltage is 3.1V ?
1.5V – 3.8V – 0.6V or only 250mV. However if the input
voltage is raised to 3.2V the advantage voltage jumps to
400mV—a 60% improvement in available strength! Note
that a similar improvement in advantage voltage can be
achieved by operating the LTC3202 at a lower voltage
setting such as the 0.4V setting.
V IN , V OUT Capacitor Selection
The style and value of capacitors used with the LTC3202
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 IN and C OUT . Tantalum and aluminum
capacitors are not recommended because of their high ESR.
The value of C OUT directly controls the amount of output
ripple for a given load current. Increasing the size of C OUT
will reduce the output ripple at the expense of higher
minimum turn-on time and higher start-up current. The
peak-to-peak output ripple is approximately given by the
expression:
in the block diagram, the LTC3202 uses a control loop to
adjust the strength of the charge pump to match the
current 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 to form the
dominant pole for the control loop. To prevent ringing or
instability, it is important for the output capacitor to
maintain at least 0.6 μ F of capacitance over all conditions.
Likewise, excessive ESR on the output capacitor will tend
to degrade the loop stability of the LTC3202. The closed-
loop output resistance of the LTC3202 is designed to be
0.35 ? . For a 100mA load current change, the feedback
voltage will change by about 35mV. If the output capacitor
has 0.35 ? or more of ESR the closed-loop frequency
response will cease to roll-off in a simple one-pole fashion
and poor load transient response or instability could
result. Multilayer ceramic chip capacitors typically have
exceptional ESR performance and combined with a tight
board layout should yield very good stability and load
transient performance.
As the value of C OUT controls the amount of output ripple,
the value of C IN controls the amount of ripple present at the
input pin (V IN ). The input current to the LTC3202 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 (~25ns) these missing “notches”
will result in only a small 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 capaci-
tors are again recommended for their exceptional ESR
V RIPPLEP ? P ?
I OUT
3 f OSC ? C OUT
performance.
Further input noise reduction can be achieved by powering
the LTC3202 through a very small series inductor as
Where f OSC is the LTC3202’s oscillator frequency (typi-
cally 1.5MHz) and C OUT is the output charge storage
capacitor.
Both the style and value of the output capacitor can
significantly affect the stability of the LTC3202. As shown
shown in Figure 5. A 10nH inductor 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.
3202fa
8
相关PDF资料 |
PDF描述 |
|---|---|
| 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 |
| REC5-483.3DRW/H2/A/M/SMD/CTRL | CONV DC/DC 5W 36-72VIN +/-3.3V |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3202EMS#PBF | 功能描述:IC LED DRVR WHITE BCKLGT 10-MSOP 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 |
| LTC3202EMS#TR | 功能描述:IC LED DRVR WHITE BCKLGT 10-MSOP 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 |
| LTC3202EMS#TRPBF | 功能描述:IC LED DRVR WHITE BCKLGT 10-MSOP 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 |
| 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 |
发布紧急采购，3分钟左右您将得到回复。