参数资料
| 型号： | LT3012HFE#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 11/16页 |
| 文件大小： | 0K |
| 描述： | IC REG LDO ADJ .2A 16-TSSOP |
| 产品培训模块： | More Information on LDOs |
| 标准包装： | 2,500 |
| 稳压器拓扑结构： | 正，可调式 |
| 输出电压： | 1.24 V ~ 60 V |
| 输入电压： | 4 V ~ 80 V |
| 电压 - 压降（标准）： | 0.36V @ 200mA |
| 稳压器数量： | 1 |
| 电流 - 输出： | 200mA |
| 电流 - 限制（最小）： | 200mA |
| 工作温度： | -40°C ~ 140°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 16-TSSOP（0.173"，4.40mm）裸露焊盘 |
| 供应商设备封装： | 16-TSSOP-EP |
| 包装： | 带卷 (TR) |
LT3012
APPLICATIONS INFORMATION
For an application with transient high power peaks, average
power dissipation can be used for junction temperature
calculations as long as the pulse period is signi?cantly less
than the thermal time constant of the device and board.
Calculating Junction Temperature
Example 1: Given an output voltage of 5V, an input volt-
age range of 24V to 30V, an output current range of 0mA
to 50mA, and a maximum ambient temperature of 50°C,
what will the maximum junction temperature be?
The power dissipated by the device will be equal to:
I OUT(MAX) ? (V IN(MAX) – V OUT ) + (I GND ? V IN(MAX) )
where:
I OUT(MAX) = 50mA
V IN(MAX) = 30V
I GND at (I OUT = 50mA, V IN = 30V) = 1mA
So:
P = 50mA ? (30V – 5V) + (1mA ? 30V) = 1.28W
The thermal resistance will be in the range of 40°C/W to
62°C/W depending on the copper area. So the junction
temperature rise above ambient will be approximately
equal to:
1.31W ? 50°C/W = 65.5°C
The maximum junction temperature will then be equal to
the maximum junction temperature rise above ambient
plus the maximum ambient temperature or:
T JMAX = 50°C + 65.5°C = 115.5°C
Example 2: Given an output voltage of 5V, an input voltage
of 48V that rises to 72V for 5ms(max) out of every 100ms,
and a 5mA load that steps to 50mA for 50ms out of every
250ms, what is the junction temperature rise above ambi-
ent? Using a 500ms period (well under the time constant
of the board), power dissipation is as follows:
P1(48V in, 5mA load) = 5mA ? (48V – 5V)
+ (200μA ? 48V) = 0.23W
P3(72V in, 5mA load) = 5mA ? (72V – 5V)
+ (200μA ? 72V) = 0.35W
P4(72V in, 50mA load) = 50mA ? (72V – 5V)
+ (1mA ? 72V) = 3.42W
Operation at the different power levels is as follows:
76% operation at P1, 19% for P2, 4% for P3, and
1% for P4.
P EFF = 76%(0.23W) + 19%(2.20W) + 4%(0.35W)
+ 1%(3.42W) = 0.64W
With a thermal resistance in the range of 40°C/W to
62°C/W, this translates to a junction temperature rise
above ambient of 26°C to 38°C.
High Temperature Operation
Care must be taken when designing LT3012 applications to
operate at high ambient temperatures. The LT3012 works
at elevated temperatures but erratic operation can occur
due to unforeseen variations in external components. Some
tantalum capacitors are available for high temperature
operation, but ESR is often several ohms; capacitor ESR
above 3Ω is unsuitable for use with the LT3012. Ceramic
capacitor manufacturers (Murata, AVX, TDK, and Vishay
Vitramon at this writing) now offer ceramic capacitors that
are rated to 150°C using an X8R dielectric. Device instability
will occur if output capacitor value and ESR are outside
design limits at elevated temperature and operating DC
voltage bias (see information on capacitor characteristics
under Output Capacitance and Transient Response). Check
each passive component for absolute value and voltage
ratings over the operating temperature range.
Leakages in capacitors or from solder ?ux left after
insuficient board cleaning adversely affects low
quiescent current operation. The output voltage resistor
divider should use a maximum bottom resistor value of
124k to compensate for high temperature leakage, setting
divider current to 10μA. Consider junction temperature
increase due to power dissipation in both the junction and
nearby components to ensure maximum speci?cations are
not violated for the device or external components.
P2(48V in, 50mA load) = 50mA ? (48V – 5V)
+ (1mA ? 48V) = 2.20W
3012fd
11
相关PDF资料 |
PDF描述 |
|---|---|
| LT3013MPFE#PBF | IC REG LDO ADJ .25A 16-TSSOP |
| LT3014HVIS5#TRPBF | IC REG LDO ADJ 20MA SOT23-5 |
| LT3015MPQ-5#TRPBF | IC REG LDO -5V 1.5A DDPAK-5 |
| LT3020IDD#TRPBF | IC REG LDO ADJ .1A 8-DFN |
| LT3021IS8-1.8#TRPBF | IC REG LDO 1.8V .5A 8-SOIC |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LT3013 | 制造商:LINER 制造商全称:Linear Technology 功能描述:250mA, 4V to 80V Low Dropout Micropower Linear Regulator with PWRGD |
| LT3013_09 | 制造商:LINER 制造商全称:Linear Technology 功能描述:250mA, 4V to 80V Low Dropout Micropower Linear Regulator with PWRGD |
| LT3013B | 制造商:LINER 制造商全称:Linear Technology 功能描述:250mA, 4V to 80V Low Dropout Micropower Linear Regulator with PWRGD |
| LT3013BEDE | 制造商:Linear Technology 功能描述:LDO Regulator Pos 1.24V to 60V 0.25A 12-Pin DFN EP |
| LT3013BEDE#PBF | 功能描述:IC REG LDO ADJ .25A 12-DFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - 线性 系列:- 标准包装:800 系列:- 稳压器拓扑结构:正，固定式 输出电压:2.5V 输入电压:最高 16V 电压 - 压降（标准）:0.7V @ 4A 稳压器数量:1 电流 - 输出:4A 电流 - 限制（最小）:4.2A 工作温度:0°C ~ 125°C 安装类型:表面贴装 封装/外壳:TO-263-6，D²Pak（5 引线+接片），TO-263BA 供应商设备封装:TO-263-5 包装:带卷 (TR) 其它名称:AP1184K525L-13AP1184K525LDITR |
发布紧急采购，3分钟左右您将得到回复。