收藏本站
LTM4615
APPLICATIONS INFORMATION
Reverse input current will spike up as LDO_IN gets to
within about 30mV of LDO_OUT as reverse current protec-
tion circuitry is disabled and normal operation resumes.
As LDO_IN transitions above LDO_OUT the reverse current
transitions into short circuit current as long as LDO_OUT
is held below the regulation voltage.
Thermal Considerations and Output Current Derating
The power loss curves in Figures 5 and 6 can be used
in coordination with the load current derating curves in
Figures 7 to 10 for calculating an approximate θ JA thermal
resistance for the LTM4615 with various heat sinking and
airflow conditions. Both of the LTM4615 outputs are at full
4A load current, and the power loss curves in Figures 5
and 6 are combined power losses plotted for both output
voltages up to 4A each. The VLDO regulator is set to have
a power dissipation of 0.5W since it is generally used with
dropout voltages of 0.5V or less. For example: 1.2V to 1V,
1.5V to 1V, 1.5V to 1.2V and 1.8V to 1.5V. Other dropout
voltages can be supported at VLDO maximum load, but
further thermal analysis will be required for the VLDO.
The 4A output voltages are 1.2V and 3.3V. These voltages
are chosen to include the lower and higher output voltage
ranges for correlating the thermal resistance. Thermal
models are derived from several temperature measure-
ments in a controlled temperature chamber along with
thermal modeling analysis. The junction temperatures are
monitored while ambient temperature is increased with and
without airflow. The junctions are maintained at ~120°C
while lowering output current or power with increasing
ambient temperature. The 120°C value is chosen to allow
for a 5°C margin window relative to the maximum 125°C
limit. The decreased output current will decrease the inter-
nal module loss as ambient temperature is increased. The
power loss curves in Figures 5 and 6 show this amount of
power loss as a function of load current that is specified
for both channels. The monitored junction temperature of
120°C minus the ambient operating temperature specifies
how much module temperature rise can be allowed. As
an example, in Figure 7 the load current is derated to 3A
for each channel with 0LFM at ~90°C and the power loss
for both channels at 5V to 1.2V at 3A output is ~1.4W.
Add the VDLO power loss of 0.5W to equal 1.9W. If the
90°C ambient temperature is subtracted from the 120°C
maximum junction temperature, then the difference of 30°C
divided by 1.9W equals a 15.7°C/W thermal resistance.
Table 2 specifies a 15°C/W value which is very close. Table
2 and Table 3 provide equivalent thermal resistances for
1.2V and 3.3V outputs with and without air flow and heat
sinking. The combined power loss for the two 4A outputs
plus the VLDO power loss can be summed together and
multiplied by the thermal resistance values in Tables 2 and
3 for module temperature rise under the specified condi-
tions. The printed circuit board is a 1.6mm thick four layer
board with two ounce copper for the two outer layers and 1
ounce copper for the two inner layers. The PCB dimensions
are 95mm × 76mm. The BGA heat sinks are listed below
Table 3. The data sheet lists the θ JC (Junction to Case)
thermal resistances under the Pin Configuration diagram.
2.5
2.0
V IN = 5V
3.0
2.5
V IN = 5V
2.0
1.5
1.5
1.0
0.5
1.0
0.5
0
0
1
2
3
4
0
0
1
2 3
4
15
LOAD CURRENT (A)
4615 F05
Figure 5. 1.2V Power Loss
For more information www.linear.com/LTM4615
LOAD CURRENT (A)
4615 F06
Figure 6. 3.3V Power Loss
4615fb
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
LTM4618IV#PBF IC DC-DC UMODULE BUCK 6A 84-LGA
LTM4619IV#PBF IC SWIT REG BUCK 4A ADJ 144LGA
LTM4627MPY#PBF IC DC/DC UMODULE 15A 133-BGA
LTM4628EV#PBF IC DC/DC UMODULE 16A 144-LGA
LTM8008HV#PBF IC DC/DC UMODULE 16-LGA
LTM8020IV#PBF IC DC/DC UMODULE 200MA 21-LGA
LTM8023MPV#PBF IC BUCK SYNC ADJ 2A 50LGA
LTM8025MPV#PBF IC CONVERTER BUCK 3A ADJ 70LGA
相关代理商/技术参数
LTM4615IVPBF 制造商:Linear Technology 功能描述:Conv DC-DC Triple Step-Down 5.5V LGA144
LTM4616 制造商:LINER 制造商全称:Linear Technology 功能描述:Low VIN, 8A DC/DC μModule Regulator
LTM4616_12 制造商:LINER 制造商全称:Linear Technology 功能描述:Dual 8A per Channel Low VIN DC/DC μModule Regulator
LTM4616EV#PBF 功能描述:IC DC/DC UMODULE DUAL 8A 144-LGA RoHS:是 类别:电源 - 板载 >> DC DC Converters 系列:µModule® 设计资源:VI-200, VI-J00 Design Guide, Appl Manual 标准包装:1 系列:* 类型:隔离 输出数:1 电压 - 输入（最小）:66V 电压 - 输入（最大）:160V Voltage - Output 1:12V Voltage - Output 2:- Voltage - Output 3:- 电流 - 输出（最大）:* 电源（瓦） - 制造商系列:50W 电压 - 隔离:* 特点:* 安装类型:通孔 封装/外壳:9-FinMod 尺寸/尺寸:4.60" L x 1.86" W x 0.79" H（116.8mm x 47.2mm x 20.1mm） 包装:散装 工作温度:-25°C ~ 85°C 效率:* 电源（瓦特）- 最大:*
LTM4616EV#PBF 制造商:Linear Technology 功能描述:DC/DC Controller LTC
LTM4616EVPBF 制造商:Linear Technology 功能描述:Conv DC-DC Dual-Out Step Down
LTM4616EV-PBF 制造商:LINER 制造商全称:Linear Technology 功能描述:Dual 8A per Channel Low VIN DC/DC μModule
LTM4616EY#PBF 功能描述:IC DC/DC UMODULE 0.6-5V 144BGA RoHS:是 类别:电源 - 板载 >> DC DC Converters 系列:µModule® 设计资源:VI-200, VI-J00 Design Guide, Appl Manual 标准包装:1 系列:* 类型:隔离 输出数:1 电压 - 输入（最小）:66V 电压 - 输入（最大）:160V Voltage - Output 1:12V Voltage - Output 2:- Voltage - Output 3:- 电流 - 输出（最大）:* 电源（瓦） - 制造商系列:50W 电压 - 隔离:* 特点:* 安装类型:通孔 封装/外壳:9-FinMod 尺寸/尺寸:4.60" L x 1.86" W x 0.79" H（116.8mm x 47.2mm x 20.1mm） 包装:散装 工作温度:-25°C ~ 85°C 效率:* 电源（瓦特）- 最大:*