- 您现在的位置：买卖IC网 > PDF目录20876 > LTC3490ES8#TRPBF (Linear Technology)IC LED DRIVER PHOTO FLASH 8-SOIC PDF资料下载
参数资料
| 型号： | LTC3490ES8#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 8/12页 |
| 文件大小： | 0K |
| 描述： | IC LED DRIVER PHOTO FLASH 8-SOIC |
| 标准包装： | 2,500 |
| 恒定电流： | 是 |
| 拓扑： | PWM，升压（升压） |
| 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： | 1MHz ~ 1.6MHz |
| 电源电压： | 1 V ~ 3.2 V |
| 输出电压： | 2.8 V ~ 4 V |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 8-SOIC（0.154"，3.90mm 宽） |
| 供应商设备封装： | 8-SOIC |
| 包装： | 带卷 (TR) |
| 工作温度： | -40°C ~ 85°C |
LTC3490
APPLICATIO S I FOR ATIO
The output ripple voltage has two primary components.
The first is due to the value of the capacitor and is given by:
Component values will be calculated for 1 or 2 NiMH cells
and assumes the end-of-charge voltage to be 0.9V per cell.
The operating frequency is assumed to be 1MHz, the
VR CAP =
I LPK ? V IN
C ? V OUT ? f
worst-case low frequency. The allowed inductor ripple
current is 0.31A. Table 3 shows a summary of the key
parameters.
The second is due to the capacitor ESR:
Table 3. Summary of Key Parameters
IR LED =
= I OUT +
IR LE D
VR ESR = I LPK ? R ESR
The LED current ripple and peak pulsed current are calcu-
lated by:
VR CAP ? VR ESR
R SENSE + R LED
I PPFC
2
where:
R SENSE = Internal Sense Resistor = 0.1 ?
PARAMETER
L MIN
Choose L
I IN
I LPK
Choose C
Cap ESR
VR CAP
VR ESR
IR LED
I PPFC
1-CELL
2.2
3.3
1.56
1.93
4.7
5
0.09
0.01
0.10
0.40
2-CELL
3.2
3.3
0.78
0.96
4.7
5
0.09
0.005
0.09
0.39
UNITS
μ H
μ H
A
A
μ F
m ?
V
V
A
A
R LED = Dynamic Impedance of the LED
Low ESR capacitors should be used to minimize output
ripple. Ceramic X5R or X7R type capacitors are recom-
mended. See Table 2 for a list of component suppliers.
where:
I LPK is the peak inductor current
VR CAP is the ripple voltage due to the output capacitor
value
Table 2. Capacitor Information
CAPACITOR PART NUMBER
TDK C2012X5R0J475K
AVX 1210ZC475MAT
Taiyo Yuden CELMK316BJ475ML
DESCRIPTION
4.7 μ F, 6.3V, X5R in 0805
4.7 μ F, 10V, X7R in 1210
4.7 μ F, 10V, X7R in 1206
VR ESR is the ripple voltage due to the output capacitor
ESR
IR LED is the LED current ripple
I PPFC is the LED peak pulsed forward current
PC Board Layout Checklist
Input Capacitor Selection
Most battery-powered applications do not need an input
capacitor. In supply-powered applications or battery ap-
plications with long leads to the battery, a low ESR 3.3 μ F
capacitor reduces switching noise and peak currents.
Design Example
The example will use a Lumileds DS25 white LED. The key
specifications are:
Keep the inductor and output capacitor as close to the IC
as possible. Make traces as short and wide as is feasible.
Parasitic resistance and inductance reduce efficiency and
increase ripple.
Keep resistance in the battery connections as low as
possible. In single cell applications, only 0.1 ? in the
battery connections will have a dramatic effect in effi-
ciency and battery life. I 2 R losses can exceed 100mW and
the converter operates lower on the efficiency curve.
V F (at I F = 350mA) = 3.4 ± 0.6V
R LED = 1 ?
Peak Pulsed Forward Current = 0.5A
3490fa
8
相关PDF资料 |
PDF描述 |
|---|---|
| NDL2412SC | CONV DC/DC 2W 24VIN 12VOUT SIP |
| LTC3220IPF#TRPBF | IC LED DRVR QVGA DISPLAY 28UTQFN |
| P51-3000-S-Z-D-4.5V-000-000 | SENSOR 3000PSI 1/4-18NPT .5-4.5V |
| REC5-2405DRWZ/H2/A/SMD/CTRL | CONV DC/DC 5W 9-36VIN +/-05VOUT |
| GEC13DREI | CONN EDGECARD 26POS .100 EYELET |
相关代理商/技术参数 |
参数描述 |
|---|---|
| AD7765 | 制造商:AD 制造商全称:Analog Devices 功能描述:24-Bit, 8.5 mW, 109 dB, 128/64/32 kSPS ADCs |
| AD7765_07 | 制造商:AD 制造商全称:Analog Devices 功能描述:24-Bit, 156 kSPS, 112 dB ヒ-ツ ADC with On-Chip Buffers and Serial Interface |
| AD7765BRUZ | 功能描述:IC ADC 24BIT S/D 156KSPS 28TSSOP RoHS:是 类别:集成电路 (IC) >> 数据采集 - 模数转换器 系列:- 其它有关文件:TSA1204 View All Specifications 标准包装:1 系列:- 位数:12 采样率（每秒）:20M 数据接口:并联 转换器数目:2 功率耗散（最大）:155mW 电压电源:模拟和数字 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:48-TQFP 供应商设备封装:48-TQFP（7x7） 包装:Digi-Reel® 输入数目和类型:4 个单端，单极；2 个差分，单极 产品目录页面:1156 (CN2011-ZH PDF) 其它名称:497-5435-6 |
| AD7765BRUZ-REEL7 | 功能描述:IC ADC 24BIT S/D 156KSPS 28TSSOP RoHS:是 类别:集成电路 (IC) >> 数据采集 - 模数转换器 系列:- 标准包装:1,000 系列:- 位数:12 采样率（每秒）:300k 数据接口:并联 转换器数目:1 功率耗散（最大）:75mW 电压电源:单电源 工作温度:0°C ~ 70°C 安装类型:表面贴装 封装/外壳:24-SOIC（0.295"，7.50mm 宽） 供应商设备封装:24-SOIC 包装:带卷 (TR) 输入数目和类型:1 个单端，单极；1 个单端，双极 |
| AD7766 | 制造商:AD 制造商全称:Analog Devices 功能描述:24-Bit, 8.5 mW, 109 dB, 128/64/32 kSPS ADCs |
发布紧急采购，3分钟左右您将得到回复。