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参数资料
| 型号： | LTC3490ES8#PBF |
| 厂商： | Linear Technology |
| 文件页数： | 6/12页 |
| 文件大小： | 0K |
| 描述： | IC LED DRIVER PHOTO FLASH 8-SOIC |
| 标准包装： | 100 |
| 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： | 管件 |
| 工作温度： | -40°C ~ 85°C |
| 产品目录页面： | 1339 (CN2011-ZH PDF) |
LTC3490
OPERATIO
I LED = 500 ? ? CTRL – 0 . 2 ? mA
TheLTC3490isahighefficiency,constantcurrentsource
for 1W high intensity white LEDs. These high intensity
LEDs require a fixed current of 350mA with a voltage
compliance of 2.8V to 4V.
The LTC3490 operates with 1 or 2 NiMH or alkaline cells.
It functions as a boost converter with a current sense re-
sistor providing the control feedback. If the battery voltage
is greater than the required LED compliance, it will cycle
off periodically to maintain the correct average current. It
features a low voltage start-up circuit that will start with an
input voltage of only 1V. Once the drive voltage exceeds
2.3V, the circuit operates from the drive voltage.
All of the loop compensation is internal; only the main filter
capacitor is needed for stable operation.
Dimming Function
During normal operation with the CTRL/SHDN pin con-
nected to V IN , the LED drive current is controlled at
350mA. The drive current can be reduced by changing the
voltage on the CTRL/SHDN pin.
For V IN ? 0.2 < V CTRL < V IN ? 0.9, the LED current is
to the battery voltage. The LED drive current is given by the
formula:
? V ?
? V IN ?
When V CTRL > V IN ? 0.9, the LED drive current is clamped
at 350mA.
Open-Circuit Protection
Since this is a boost converter attempting to drive a cur-
rent into the load, an open or high impedance load will cause
the regulator loop to increase the output voltage in an ef-
fort to achieve regulation. To protect the device, maximum
output voltage is limited to 4.7V under all conditions.
Undervoltage Sense and Protection
The undervoltage lockout prevents excessive inductor
peak current and protects the batteries from deep dis-
charging which can damage them. The low-battery indica-
tor allows the end user to be made aware that the batteries
are nearing the end of their useful life.
proportional to V CTRL /V IN . This allows a simple potenti-
ometer from V IN to control the current without sensitivity
3490fa
6
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相关代理商/技术参数 |
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| LTC3499 | 制造商:LINER 制造商全称:Linear Technology 功能描述:750mA Synchronous Step-Up DC/DC Converters with Reverse-Battery Protection |
| LTC3499B | 制造商:LINER 制造商全称:Linear Technology 功能描述:750mA Synchronous Step-Up DC/DC Converters with Reverse-Battery Protection |
| LTC3499BEDD | 制造商:LINER 制造商全称:Linear Technology 功能描述:750mA Synchronous Step-Up DC/DC Converters with Reverse-Battery Protection |
| LTC3499BEDD#PBF | 功能描述:IC REG BOOST SYNC ADJ 0.75A 8DFN 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 |
| LTC3499BEDD#TR | 制造商:Linear Technology 功能描述:Conv DC-DC Single Step Up 1.8V to 5.5V 8-Pin DFN EP T/R |
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