- 您现在的位置：买卖IC网 > PDF目录67754 > L5981 (STMICROELECTRONICS) 1 A SWITCHING REGULATOR, 1000 kHz SWITCHING FREQ-MAX, PDSO8 PDF资料下载
参数资料
| 型号： | L5981 |
| 厂商： | STMICROELECTRONICS |
| 元件分类： | 稳压器 |
| 英文描述： | 1 A SWITCHING REGULATOR, 1000 kHz SWITCHING FREQ-MAX, PDSO8 |
| 封装： | 3 X 3 MM, 1.08 MM HEIGHT, LEAD FREE, VFQFPN-8 |
| 文件页数： | 19/37页 |
| 文件大小： | 714K |
| 代理商： | L5981 |
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页当前第19页第20页第21页第22页第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
Application information
L5981
26/37
Doc ID 13004 Rev 6
5.5
Thermal considerations
The thermal design is important to prevent the thermal shutdown of device if junction
temperature goes above 150 °C. The three different sources of losses within the device are:
a)
conduction losses due to the not negligible RDS(on) of the power switch; these are
equal to:
Equation 26
Where D is the duty cycle of the application and the maximum RDSON is 220 mΩ. Note that
the duty cycle is theoretically given by the ratio between VOUT an VIN, but actually it is quite
higher to compensate the losses of the regulator. So the conduction losses increases
compared with the ideal case.
b)
switching losses due to power MOSFET turn ON and OFF; these can be
calculated as:
Equation 27
Where TRISE and TFALL are the overlap times of the voltage across the power switch (VDS)
and the current flowing into it during turn ON and turn OFF phases, as shown in Figure 16.
TSW is the equivalent switching time. For this device the typical value for the equivalent
switching time is 50 ns.
c)
Quiescent current losses, calculated as:
Equation 28
where IQ is the quiescent current (IQ = 2.4 mA).
The junction temperature TJ can be calculated as:
Equation 29
Where TA is the ambient temperature and PTOT is the sum of the power losses just seen.
RthJA is the equivalent thermal resistance junction to ambient of the device; it can be
calculated as the parallel of many paths of heat conduction from the junction to the ambient.
For this device the path through the exposed pad is the one conducting the largest amount
P
ON
R
DS on
()
I
OUT
()
2
D
=
P
SW
V
IN
I
OUT
T
RISE
T
FALL
+
()
2
------------------------------------------- Fsw
V
IN
I
OUT
T
SW
F
SW
==
P
Q
V
IN
I
Q
=
T
J
T
A
Rth
JA
P
TOT
+
=
相关PDF资料 |
PDF描述 |
|---|---|
| L5981TR | 1 A SWITCHING REGULATOR, 1000 kHz SWITCHING FREQ-MAX, PDSO8 |
| L5985 | 2 A SWITCHING REGULATOR, 1000 kHz SWITCHING FREQ-MAX, PDSO8 |
| L5985TR | 2 A SWITCHING REGULATOR, 1000 kHz SWITCHING FREQ-MAX, PDSO8 |
| L5989DTR | 5.06 A SWITCHING REGULATOR, 1000 kHz SWITCHING FREQ-MAX, PDSO16 |
| L5989D | 5.06 A SWITCHING REGULATOR, 1000 kHz SWITCHING FREQ-MAX, PDSO16 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| L5981_08 | 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:1 A step-down switching regulator |
| L5981TR | 功能描述:直流/直流开关调节器 1a Step-Down Switching Reg 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 |
| L5983 | 功能描述:直流/直流开关调节器 1.5A STEP-DOWN SWITCHING REGULATOR 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 |
| L5983_08 | 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:1.5 A step-down switching regulator |
| L5983TR | 功能描述:直流/直流开关调节器 1.5a Step-Down Switching Reg 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。