参数资料
型号: L5988D
厂商: STMICROELECTRONICS
元件分类: 稳压器
英文描述: 5.6 A SWITCHING REGULATOR, 1000 kHz SWITCHING FREQ-MAX, PDSO16
封装: LEAD FREE, HTSSOP-16
文件页数: 33/52页
文件大小: 1858K
代理商: L5988D
L5988D
Application information
Doc ID 15324 Rev 3
39/52
The red trace represents the maximum power which can be taken away as calculated
above, whilst the purple trace is the total internal losses.
As a consequence, given these operating conditions, the system can manage a continuos
output current up to 4.2 A. The device could deliver a continuos output current up to 5 A to
the load (see Chapter 6.5), however the maximum power loss of 2.5 W is reached with an
output current of 4.2 A, so the maximum output power is derated.
The calculation of the internal power losses must be done for each specific operating
condition given by the final application.
For example, the result showed in Figure 21. is not valid in case the VIN is equal to 5 V
instead of 12 V: the lower contribution of the switching losses, which are proportional to the
input voltage, increases the maximum output current from 4.2 A to 4.5 A (see Figure 22.).
Figure 22.
Estimation of the internal power losses (VIN = 5 V, VOUT = 1.2 V,
fSW = 400 kHz)
In applications where the current to the output is pulsed, the thermal impedance should be
considered instead of the thermal resistance. Also, in these conditions, the current
limitations described in Chapter 6.5 are no more valid since they are related to continuos
output current delivery.
The thermal impedance of the system could be much lower than the thermal resistance,
which is a static parameter. As a consequence the maximum power losses can be higher
than 2.5 W if a pulsed output power is requested from the load:
So, depending on the pulse duration and its frequency, the maximum output current (even
more than 5 A) can be delivered to the load.
P
MAX t
()
ΔT
Z
TH t
()
-----------------
T
J MAX
T
AMB
Z
TH t
()
--------------------------------------
==
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相关代理商/技术参数
参数描述
L5988DTR 功能描述:直流/直流开关调节器 4A Step Down Reg 2.9V to 18V 200ns 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
L5989D 功能描述:直流/直流开关调节器 4A cont 5A pulsed step-down sw 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
L5989DTR 功能描述:直流/直流开关调节器 4A cont 5A pulsed step-down sw 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
L5991 功能描述:电流型 PWM 控制器 Prog Current Mode RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14
L5991_01 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:PRIMARY CONTROLLER WITH STANDBY