参数资料
| 型号： | LT1117CST-2.85 |
| 厂商： | Linear Technology |
| 文件页数： | 8/16页 |
| 文件大小： | 0K |
| 描述： | IC REG LDO 2.85V .8A SOT-223 |
| 产品培训模块： | More Information on LDOs |
| 标准包装： | 78 |
| 稳压器拓扑结构： | 正，固定式 |
| 输出电压： | 2.85V |
| 输入电压： | 最高 10V |
| 电压 - 压降（标准）： | 1.1V @ 800mA |
| 稳压器数量： | 1 |
| 电流 - 输出： | 800mA |
| 电流 - 限制（最小）： | 800mA |
| 工作温度： | 0°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | TO-261-4，TO-261AA |
| 供应商设备封装： | SOT-223 |
| 包装： | 管件 |
LT1117/LT1117-2.85
LT1117-3.3/LT1117-5
APPLICATIONS INFORMATION
Output Voltage
R P
The LT1117 develops a 1.25V reference voltage between the
output and the adjust terminal (see Figure 2). By placing a
V IN
IN
LT1117
ADJ
OUT
PARASITIC
LINE RESISTANCE
resistor between these two terminals, a constant current
is caused to flow through R1 and down through R2 to
set the overall output voltage. Normally this current is
chosen to be the specified minimum load current of 10mA.
Because I ADJ is very small and constant when compared
R1
CONNECT
R1 TO CASE
R2
R L
to the current through R1, it represents a small error and
can usually be ignored. For fixed voltage devices R1 and
R2 are included in the device.
CONNECT
R2 TO LOAD
1117 F03
Figure 3. Connections for Best Load Regulation
LT1117
V IN
+
IN
I ADJ
50 μ A
ADJ
OUT
V REF
R1
V OUT
For fixed voltage devices the top of R1 is internally Kelvin
connected, and the ground pin can be used for negative
side sensing.
V OUT = V REF 1 + — + I ADJ R2
R2
R1
R2
1117 F02
Thermal Considerations
Figure 2. Basic Adjustable Regulator
Load Regulation
Because the LT1117 is a 3-terminal device, it is not possible
to provide true remote load sensing. Load regulation will be
limited by the resistance of the wire connecting the regulator
to the load. The data sheet specification for load regulation
is measured at the output pin of the device. Negative side
sensing is a true Kelvin connection, with the bottom of the
output divider returned to the negative side of the load.
Although it may not be immediately obvious, best load
regulation is obtained when the top of the resistor divider
(R1) is returned directly to the output pin of the device,
not to the load. This is illustrated in Figure 3. Connected
as shown, R P is not multiplied by the divider ratio. If R1
were connected to the load, the effective resistance between
the regulator and the load would be:
LT1117 series regulators have internal thermal limiting
circuitry designed to protect the device during overload
conditions. For continuous normal load conditions however,
the maximum junction temperature rating of 125°C must
not be exceeded.
It is important to give careful consideration to all sources
of thermal resistance from junction to ambient. For
the SOT-223 package, which is designed to be surface
mounted, additional heat sources mounted near the device
must also be considered. Heat sinking is accomplished
using the heat spreading capability of the PC board and
its copper traces. The thermal resistance of the LT1117 is
15°C/W from the junction to the tab. Thermal resistances
from tab to ambient can be as low as 30°C/W. The total
thermal resistance from junction to ambient can be as low
as 45°C/W. This requires a reasonable sized PC board with
at least one layer of copper to spread the heat across the
board and couple it into the surrounding air.
R P ×
R 2 + R 1
, R P = Parasitic Line Resistance
R 1
1117fd
8
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LT1117CST-3.3 | 功能描述:IC REG LDO 3.3V .8A SOT-223 RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - 线性 系列:- 产品培训模块:More Information on LDOs 标准包装:50 系列:- 稳压器拓扑结构:正，固定式 输出电压:3.3V 输入电压:最高 15V 电压 - 压降（标准）:1.1V @ 800mA 稳压器数量:1 电流 - 输出:800mA 电流 - 限制（最小）:800mA 工作温度:0°C ~ 125°C 安装类型:表面贴装 封装/外壳:TO-263-4，D²Pak（3 引线+接片），TO-263AA 供应商设备封装:D2PAK-3 包装:管件 |
| LT1117CST-3.3#PBF | 功能描述:IC REG LDO 3.3V .8A SOT-223 RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - 线性 系列:- 产品培训模块:MIC5365/66 Ultra-small LDO Regulators 标准包装:1 系列:- 稳压器拓扑结构:正，固定式 输出电压:3V 输入电压:最高 5.5V 电压 - 压降（标准）:0.155V @ 150mA 稳压器数量:1 电流 - 输出:150mA 电流 - 限制（最小）:200mA 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:4-UDFN 裸露焊盘，4-TMLF? 供应商设备封装:4-TMLF?（1x1） 包装:Digi-Reel® 其它名称:576-3192-6 |
| LT1117CST-3.3#PBF | 制造商:Linear Technology 功能描述:Linear Voltage Regulator IC 制造商:Linear Technology 功能描述:IC, LDO VOLT REG, 3.3V, 0.8A, SOT-223-3 |
| LT1117CST-3.3#TR | 功能描述:IC REG LDO 3.3V .8A SOT-223 RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - 线性 系列:- 产品培训模块:More Information on LDOs 标准包装:50 系列:- 稳压器拓扑结构:正，固定式 输出电压:3.3V 输入电压:最高 15V 电压 - 压降（标准）:1.1V @ 800mA 稳压器数量:1 电流 - 输出:800mA 电流 - 限制（最小）:800mA 工作温度:0°C ~ 125°C 安装类型:表面贴装 封装/外壳:TO-263-4，D²Pak（3 引线+接片），TO-263AA 供应商设备封装:D2PAK-3 包装:管件 |
| LT1117CST-3.3#TRPBF | 功能描述:IC REG LDO 3.3V .8A SOT-223 RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - 线性 系列:- 产品培训模块:More Information on LDOs 标准包装:50 系列:- 稳压器拓扑结构:正，固定式 输出电压:3.3V 输入电压:最高 15V 电压 - 压降（标准）:1.1V @ 800mA 稳压器数量:1 电流 - 输出:800mA 电流 - 限制（最小）:800mA 工作温度:0°C ~ 125°C 安装类型:表面贴装 封装/外壳:TO-263-4，D²Pak（3 引线+接片），TO-263AA 供应商设备封装:D2PAK-3 包装:管件 |
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