- 您现在的位置：买卖IC网 > PDF目录17413 > LM2735YMFEVAL (National Semiconductor)BOARD EVAL LM2735 520KHZ 6LLP PDF资料下载
参数资料
| 型号： | LM2735YMFEVAL |
| 厂商： | National Semiconductor |
| 文件页数： | 23/58页 |
| 文件大小： | 0K |
| 描述： | BOARD EVAL LM2735 520KHZ 6LLP |
| 标准包装： | 1 |
| 主要目的： | DC/DC，步升 |
| 输出及类型： | 1，非隔离 |
| 输出电压： | 12V |
| 电流 - 输出： | 500mA |
| 输入电压： | 3 ~ 5.5 V |
| 稳压器拓扑结构： | 升压 |
| 频率 - 开关： | 520kHz |
| 板类型： | 完全填充 |
| 已供物品： | 板 |
| 已用 IC / 零件： | LM2735 |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页当前第23页第24页第25页第26页第27页第28页第29页第30页第31页第32页第33页第34页第35页第36页第37页第38页第39页第40页第41页第42页第43页第44页第45页第46页第47页第48页第49页第50页第51页第52页第53页第54页第55页第56页第57页第58页
Total Power Losses are:
Table 3. Power Loss Tabulation
SNVS485F – JUNE 2007 – REVISED APRIL 2013
V IN
V OUT
5V
12V
I OUT
V D
F SW
T RISE
T FALL
I Q
R DSon
R DCR
D
η
P INTERNAL = P COND + P SW = 475 mW
500mA
0.4V
1.6MHz
6nS
5nS
4mA
250m ?
75m ?
0.623
86%
POUT
PDIODE
PSWR
PSWF
PQ
PCOND
PIND
PLOSS
6W
236mW
80mW
70mW
20mW
305mW
145mW
856mW
(46)
Calculating R T JA and R < JC
R T JA =
T J - T A
P Dissipatio n
and
R < JC =
T J - T CASE
P Dissipatio n
(47)
We now know the internal power dissipation, and we are trying to keep the junction temperature at or below
125°C. The next step is to calculate the value for R θ JA and/or R ψ JC . This is actually very simple to accomplish,
and necessary if you think you may be marginal with regards to thermals or determining what package option is
correct.
The LM2735 has a thermal shutdown comparator. When the silicon reaches a temperature of 160°C, the device
shuts down until the temperature reduces to 150°C. Knowing this, one can calculate the R θ JA or the R ψ JC of a
specific application. Because the junction to top case thermal impedance is much lower than the thermal
impedance of junction to ambient air, the error in calculating R ψ JC is lower than for R θ JA . However, you will need
to attach a small thermocouple onto the top case of the LM2735 to obtain the R ψ JC value.
Knowing the temperature of the silicon when the device shuts down allows us to know three of the four variables.
Once we calculate the thermal impedance, we then can work backwards with the junction temperature set to
125°C to see what maximum ambient air temperature keeps the silicon below the 125°C temperature.
Procedure:
Place your application into a thermal chamber. You will need to dissipate enough power in the device so you can
obtain a good thermal impedance value.
Raise the ambient air temperature until the device goes into thermal shutdown. Record the temperatures of the
ambient air and/or the top case temperature of the LM2735. Calculate the thermal impedances.
Copyright ? 2007–2013, Texas Instruments Incorporated
Product Folder Links: LM2735
23
相关PDF资料 |
PDF描述 |
|---|---|
| SP7652EB | EVAL BOARD FOR SP7652 |
| A9BAA-1002E | FLEX CABLE - AFJ10A/AE10/AFH10T |
| 1SMA5923BT3G | DIODE ZENER 8.2V 1.5W SMA |
| LM2735XSDEVAL | BOARD EVAL LM2735 1.6MHZ 6LLP |
| RB-0524D/P | CONV DC/DC 1W 5VIN +/-24VOUT |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LM2735YMFEVAL | 制造商:Texas Instruments 功能描述:EVAL BOARD, LM2735YMF, 500mA SEPIC CONVE |
| LM2735YMFX | 制造商:NSC 制造商全称:National Semiconductor 功能描述:520kHz/1.6MHz - Space-Efficient Boost and SEPIC DC-DC Regulator |
| LM2735YMFX/NOPB | 功能描述:直流/直流开关调节器 RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| LM2735YMY | 制造商:NSC 制造商全称:National Semiconductor 功能描述:520kHz/1.6MHz - Space-Efficient Boost and SEPIC DC-DC Regulator |
| LM2735YMY/NOPB | 功能描述:直流/直流开关调节器 RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
发布紧急采购，3分钟左右您将得到回复。