- 您现在的位置：买卖IC网 > PDF目录44551 > LM2794BL/NOPB (NATIONAL SEMICONDUCTOR CORP) SWITCHED CAPACITOR REGULATOR, 675 kHz SWITCHING FREQ-MAX, PBGA14 PDF资料下载
参数资料
| 型号： | LM2794BL/NOPB |
| 厂商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分类： | 稳压器 |
| 英文描述： | SWITCHED CAPACITOR REGULATOR, 675 kHz SWITCHING FREQ-MAX, PBGA14 |
| 封装： | LEAD FREE, CSP-14 |
| 文件页数： | 6/16页 |
| 文件大小： | 487K |
| 代理商： | LM2794BL/NOPB |
Application Information (Continued)
E=(P
LED ÷PIN)
Efficiency, as defined here, is in part dependent on LED
voltage. Variation in LED voltage does not affect power
consumed by the circuit and typically does not relate to the
brightness of the LED. For an advanced analysis, it is rec-
ommended that power consumed by the circuit (V
IN xIIN)be
evaluated rather than power efficiency. Figure 7 shows the
power consumption of the LM2794/5 Typical Application Cir-
cuit.
POWER DISSIPATION
The power dissipation (P
DISSIPATION) and junction tempera-
ture (T
J) can be approximated with the equations below. PIN
is the power generated by the 1.5x charge pump, P
LED is the
power consumed by the LEDs, P
POUT is the power provided
through the P
OUT pin, TAis the ambient temperature, and
θ
JA
is the junction-to-ambient thermal resistance for the micro
SMD-14 package. V
IN is the input voltage to the LM2794/5,
V
DX is the LED forward voltage, IDX is the programmed LED
current, and I
POUT is the current drawn through POUT.
P
DISSIPATION =PIN -PLED PPOUT
= [1.5xV
INx(4IDX +IPOUT)](VDXx4IDX) (1.5xVINxIPOUT)
T
J =TA +(PDISSIPATION x
θ
JA)
The junction temperature rating takes precedence over the
ambient temperature rating. The LM2794/5 may be operated
outside the ambient temperature rating, so long as the junc-
tion temperature of the device does not exceed the maxi-
mum operating rating of 100C. The maximum ambient tem-
perature rating must be derated in applications where high
power dissipation and/or poor thermal resistance causes the
junction temperature to exceed 100C.
MICRO SMD MOUNTING
The LM2794/5 is a 14-bump micro SMD with a bump size of
300 micron diameter. The micro SMD package requires
specific mounting techniques detailed in National Semicon-
ductor Application Note (AN -1112). NSMD (non-solder mask
defined) layout pattern is recommended over the SMD (sol-
der mask defined) since the NSMD requires larger solder
mask openings over the pad size as opposed to the SMD.
This reduces stress on the PCB and prevents possible
cracking at the solder joint. For best results during assembly,
alignment ordinals on the PC board should be used to
facilitate placement of the micro SMD device. Micro SMD is
a wafer level chip size package, which means the dimen-
sions of the package are equal to the die size. As such, the
micro SMD package lacks the plastic encapsulation charac-
teristics of the larger devices and is sensitive to direct expo-
sure to light sources such as infrared, halogen, and sun light.
The wavelengths of these light sources may cause unpre-
dictable operation.
20028537
FIGURE 6. Efficiency vs V
IN
4 LEDs, V
LED = 3.6V, ILED = 15mA
20028538
FIGURE 7. P
IN vs VIN
4 LEDs, 2.5
≤ V
DX
≤ 3.9V, I
DX = 15mA
LM2794/LM2795
www.national.com
14
相关PDF资料 |
PDF描述 |
|---|---|
| LM2797MM-1.8/NOPB | 0.12 A SWITCHED CAPACITOR REGULATOR, PDSO10 |
| LM2797MMX-1.8/NOPB | 0.12 A SWITCHED CAPACITOR REGULATOR, PDSO10 |
| LM2798MMX-1.5/NOPB | 0.12 A SWITCHED CAPACITOR REGULATOR, 500 kHz SWITCHING FREQ-MAX, PDSO10 |
| LM2798MM-2.0/NOPB | 0.12 A SWITCHED CAPACITOR REGULATOR, 500 kHz SWITCHING FREQ-MAX, PDSO10 |
| LM2798MMX-2.0/NOPB | 0.12 A SWITCHED CAPACITOR REGULATOR, 500 kHz SWITCHING FREQ-MAX, PDSO10 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LM2794BLX | 制造商:Texas Instruments 功能描述: |
| LM2794EVAL | 功能描述:电源管理IC开发工具 EVAL KIT FOR LM2794 RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
| LM2794TL | 功能描述:IC LED DRVR WHT BCKLT 14MICROSMD RoHS:否 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- 恒定电流:- 恒定电压:- 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:背光 类型 - 次要:白色 LED 频率:625kHz ~ 875kHz 电源电压:2.7 V ~ 5.3 V 输出电压:5V 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-µMAX 包装:带卷 (TR) 工作温度:-40°C ~ 85°C |
| LM2794TL/NOPB | 功能描述:LED照明驱动器 RoHS:否 制造商:STMicroelectronics 输入电压:11.5 V to 23 V 工作频率: 最大电源电流:1.7 mA 输出电流: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:SO-16N |
| LM2794TLX | 功能描述:IC LED DRVR WHT BCKLT 14USMD RoHS:否 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- 恒定电流:- 恒定电压:- 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:背光 类型 - 次要:白色 LED 频率:625kHz ~ 875kHz 电源电压:2.7 V ~ 5.3 V 输出电压:5V 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-µMAX 包装:带卷 (TR) 工作温度:-40°C ~ 85°C |
发布紧急采购，3分钟左右您将得到回复。