收藏本站
LMZ14201
www.ti.com
SNVS649F – JANUARY 2010 – REVISED OCTOBER 2013
Following is a comparison pair of waveforms of the showing both CCM (upper) and DCM operating modes.
Figure 33. CCM and DCM Operating Modes
V IN = 12V, V O = 3.3V, I O = 1 A / 0.25 A
500 mA/Div
2.00 2 s/Div
The approximate formula for determining the DCM/CCM boundary is as follows:
I DCB ? V O *(V IN –V O )/(2*10 μ H*f SW(CCM) *V IN )
Following is a typical waveform showing the boundary condition.
Figure 34. Transition Mode Operation
V IN = 24V, V O = 3.3V, I O = 0.29 A
(16)
500 mA/Div
2.00 2 s/Div
The inductor internal to the module is 10 μ H. This value was chosen as a good balance between low and high
input voltage applications. The main parameter affected by the inductor is the amplitude of the inductor ripple
current (I LR ). I LR can be calculated with:
I LR P-P =V O *(V IN - V O )/(10μH*f SW *V IN )
(17)
Where V IN is the maximum input voltage and f SW is determined from Equation 10 .
If the output current I O is determined by assuming that I O = I L , the higher and lower peak of I LR can be
determined. Be aware that the lower peak of I LR must be positive if CCM operation is required.
POWER DISSIPATION AND BOARD THERMAL REQUIREMENTS
For the design case of V IN = 24V, V O = 3.3V, I O = 1A, T AMB(MAX) = 85°C , and T JUNCTION = 125°C, the device must
see a thermal resistance from case to ambient of less than:
θ CA < (T J-MAX — T AMB(MAX) ) / P IC-LOSS - θ JC
(18)
Given the typical thermal resistance from junction to case to be 1.9 °C/W. Use the 85°C power dissipation curves
in the Typical Performance Characteristics section to estimate the P IC-LOSS for the application being designed. In
this application it is 0.52W.
θ CA = (125 — 85) / 0.52W — 1.9 = 75
To reach θ CA = 75, the PCB is required to dissipate heat effectively. With no airflow and no external heat, a good
estimate of the required board area covered by 1 oz. copper on both the top and bottom metal layers is:
Board Area_cm 2 = 500°C x cm 2 /W / θ JC
(19)
Copyright ? 2010–2013, Texas Instruments Incorporated
Product Folder Links: LMZ14201
Submit Documentation Feedback
15
发布紧急采购，3分钟左右您将得到回复。

采购需求

(若只采购一条型号，填写一行即可)

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

*型号 *数量 厂商 批号 封装
添加更多采购

我的联系方式

*
*
*
相关PDF资料
LMZ14203EXTTZE/NOPB IC BUCK SYNC ADJ 3A TO-PMOD-7
LNC2W153MSEJ CAP ALUM 15000UF 450V 20% SCREW
LNK2H822MSEJ CAP ALUM 8200UF 500V 20% SCREW
LNT2H103MSEJ CAP ALUM 10000UF 500V 20% SCREW
LNX2J562MSEK CAP ALUM 5600UF 630V 20% SCREW
LNY2W153MSEJ CAP ALUM 15000UF 450V 20% SCREW
LP122M250H9P3 CAP ALUM 1200UF 250V 20% SNAP
LPW332M2AP45V-W CAP ALUM 3300UF 100V 20% SNAP
相关代理商/技术参数
LMZ14201TZEADJNOPB 制造商:Texas Instruments 功能描述:Module DC-DC 1-OUT 0.8V to 6V 1A 7-Pin TO-PMOD EP
LMZ14201TZX-ADJ 制造商:NSC 制造商全称:National Semiconductor 功能描述:1A SIMPLE SWITCHER? Power Module with 42V Maximum Input Voltage
LMZ14201TZX-ADJ/NOPB 功能描述:直流/直流开关转换器 RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT
LMZ14201TZXADJNOPB 制造商:Texas Instruments 功能描述:Module DC-DC 1-OUT 0.8V to 6V 1A 7-Pin TO-PMOD EP
LMZ14202 制造商:NSC 制造商全称:National Semiconductor 功能描述:2A SIMPLE SWITCHER? Power Module with 42V Maximum Input Voltage
LMZ14202_1 制造商:NSC 制造商全称:National Semiconductor 功能描述:2A SIMPLE SWITCHER?? Power Module with 42V Maximum Input Voltage
LMZ14202_11 制造商:NSC 制造商全称:National Semiconductor 功能描述:2A SIMPLE SWITCHER? Power Module with 42V Maximum Input Voltage
LMZ14202EVAL/NOPB 功能描述:电源管理IC开发工具 LMZ14202EVAL BOARD 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