LD1117S50TR - 800mA Low Dropout Positive Regulator | STMicroelectronics
料号： LD1117S50TR ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $0.35 | $0.35 |
| 10 | $0.3 | $3.00 |
| 100 | $0.25 | $25.00 |
| 500 | $0.2 | $100.00 |
| 1,000 | $0.18 | $180.00 |
LD1117S50TR 概述
A low dropout (LDO) regulator is a type of linear voltage regulator that can maintain a regulated output voltage even when the input voltage is very close to the output voltage. This is achieved by using a pass transistor that operates in the saturation region, minimizing the voltage drop across the regulator. LDO regulators are essential in power management systems where efficiency and noise are critical, such as in battery-powered devices, automotive electronics, and industrial control systems. They are part of the broader category of voltage regulators, which also includes switching regulators and charge pumps, each with distinct trade-offs in efficiency, noise, and complexity.
Key features of the LD1117S50TR include a low dropout voltage of 1.1V at 800mA, a typical quiescent current of 5mA, and a load regulation of 0.2% typical. The device also includes internal current limiting and thermal shutdown protection, ensuring safe operation under fault conditions. The SOT-223 package offers a thermal resistance of 50°C/W (junction-to-ambient), allowing for moderate power dissipation without external heatsinking in many applications.
The LD1117S50TR utilizes a PNP pass transistor architecture, which provides a low dropout voltage and stable operation. The internal bandgap reference ensures accurate output voltage regulation across temperature and load variations. The device is designed to be stable with a wide range of output capacitors, including ceramic capacitors, which simplifies the design and reduces the overall solution size.
Typical applications include post-regulation of switching power supplies, battery-powered equipment, and as a local 5V rail for microcontrollers, sensors, and analog circuits. The fixed 5V output is ideal for logic circuits and USB-powered devices. The low dropout voltage allows efficient operation even when the input voltage is only slightly above the output, maximizing battery life in portable applications.
When designing with the LD1117S50TR, it is important to ensure adequate input-to-output voltage headroom to maintain regulation under all load conditions. The input and output capacitors should be placed close to the device pins to minimize parasitic inductance and ensure stability. The exposed tab of the SOT-223 package should be connected to a copper pour to enhance thermal dissipation, especially when operating at high load currents.
直接替换替代料： LD1117S50TR ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
本系列中的变体
可与以下型号直接替换的同系列型号： LD1117S50TR （相同外形与封装尺寸） ——差异在于 Input Voltage Range, Line Regulation, Load Regulation, Output Voltage, Dropout Voltage.
快速对比工具——选择替代料号进行并排对比：
LD1117S33TR
✅ 直接替换 ⚠️ 规格未核验✓ 有现货
$0.2 / 个
查看数据手册 →LD1117S12TR
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
LD1117S18TR
✅ 直接替换 ⚠️ 规格未核验✓ 有现货
$0.15 / 个
查看数据手册 →AMS1117-5.0
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
NCP1117ST50T3G
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
AP1117-5.0
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
LD1117S50TR 最大额定值与电气特性
| 输出类型 | Fixed |
| 输出电压 | 5.0 V |
| 最大输出电流 | 800 mA |
| 输入电压范围 | 6.5 V to 15 V |
| 压差电压 | 1.1 V at 800 mA |
| 静态电流 | 5 mA typical |
| Load Regulation | 0.2% typical |
| Line Regulation | 0.2% typical |
| 热阻，结到环境 | 50 °C/W |
| 工作温度范围 | -40°C to +125°C |
| 封装 | SOT-223 |
| 安装类型 | Surface Mount |
| MSL 等级 | 1 (unlimited) |
| RoHS 状态 | Compliant |
| Protection Features | Current limiting, thermal shutdown |
LD1117S50TR 引脚配置
| 引脚 1 | GND — Ground |
| 引脚 2 | VOUT — Regulated 5V output |
| 引脚 3 | VIN — Input supply voltage |
| 引脚 Tab | VOUT — Exposed tab connected to output for thermal dissipation |
典型应用
LD1117S50TR 适用于 6 应用s: Post-Regulation of Switching Power Supplies, Battery-Powered Equipment, Local 5V Rail for Microcontrollers, USB-Powered Devices, Industrial Control Systems, Audio Equipment.
Post-Regulation of Switching Power Supplies
The LD1117S50TR is used to provide a clean, regulated 5V rail after a switching regulator. Its low dropout voltage and low output noise ensure that the downstream circuitry receives a stable supply, reducing ripple and improving performance. In a typical application, the LD1117S50TR is placed after a buck converter that outputs 6.5V to 15V, and it regulates down to 5V with a maximum current of 800mA. The low dropout voltage of 1.1V allows efficient operation even when the input is only slightly above the output, minimizing power dissipation. The device's internal current limiting and thermal shutdown protect the system under fault conditions. Compared to using a switching regulator alone, the LDO provides a cleaner output with lower noise, which is critical for analog and RF circuits. The SOT-223 package with exposed tab allows for adequate thermal dissipation, making it suitable for continuous operation at moderate loads.
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Battery-Powered Equipment
In battery-powered devices, the LD1117S50TR provides a stable 5V rail from a battery voltage that may vary between 6.5V and 15V. Its low quiescent current of 5mA helps extend battery life, and the low dropout voltage ensures efficient use of the battery's energy as it discharges. For example, in a portable instrument powered by a 9V battery, the LD1117S50TR regulates the voltage down to 5V for the microcontroller and sensors. The device's thermal shutdown and current limiting protect the battery and the load from overcurrent and overheating. The SOT-223 package is compact and suitable for space-constrained designs. The low dropout voltage allows the regulator to continue providing a stable output even when the battery voltage drops close to 6.5V, maximizing the usable battery capacity. This makes the LD1117S50TR an excellent choice for portable and handheld devices.
推荐
Local 5V Rail for Microcontrollers
The LD1117S50TR is ideal for providing a local 5V rail to microcontrollers and digital logic circuits. Its fixed 5V output is compatible with standard logic levels, and the low dropout voltage allows it to operate from a 6.5V input with minimal power loss. In a typical design, the LD1117S50TR is placed near the microcontroller to provide a clean, regulated supply, reducing noise and ensuring reliable operation. The device's fast transient response helps maintain stable voltage during sudden load changes, such as when the microcontroller wakes from sleep mode. The SOT-223 package is easy to solder and fits well in compact PCB layouts. The internal current limiting and thermal shutdown provide additional protection for the microcontroller and the regulator itself. This application is common in industrial control, consumer electronics, and IoT devices.
推荐
USB-Powered Devices
The LD1117S50TR can be used in USB-powered devices to provide a stable 5V rail from the USB bus voltage. Although USB provides 5V, the actual voltage can vary between 4.75V and 5.25V, and the LD1117S50TR can regulate this to a precise 5V output. However, the input voltage range of 6.5V to 15V means that the LD1117S50TR cannot be directly powered from a standard 5V USB supply. Instead, it is often used in devices that have a higher input voltage, such as a boost converter that steps up the USB voltage to 6.5V or higher. In such designs, the LD1117S50TR provides a clean, regulated 5V rail for the main circuitry. The low dropout voltage ensures efficient operation, and the thermal shutdown protects the device in case of overcurrent. This application is common in USB hubs, chargers, and other peripherals.
推荐
Industrial Control Systems
In industrial control systems, the LD1117S50TR provides a reliable 5V rail for sensors, microcontrollers, and communication interfaces. Its wide input voltage range of 6.5V to 15V allows it to be powered from common industrial supply rails such as 12V or 24V (with appropriate stepping down). The device's robust protection features, including current limiting and thermal shutdown, ensure reliable operation in harsh environments. The low dropout voltage minimizes power dissipation, reducing the need for large heatsinks. The SOT-223 package is rugged and suitable for industrial PCB assemblies. The LD1117S50TR's stable output voltage and low noise make it ideal for analog sensor interfaces and precision measurement circuits. This application is common in factory automation, process control, and building management systems.
推荐
Audio Equipment
The LD1117S50TR can be used in audio equipment to provide a clean 5V rail for audio codecs, amplifiers, and digital signal processors. Its low output noise and stable regulation help minimize audio distortion and interference. In a typical audio application, the LD1117S50TR is used to power the analog and digital sections of an audio codec, ensuring that the supply voltage is free from ripple and noise. The low dropout voltage allows efficient operation from a 6.5V input, which is common in battery-powered audio devices. The device's fast transient response ensures that the voltage remains stable during dynamic audio peaks. The SOT-223 package is compact and suitable for portable audio devices. The LD1117S50TR's thermal shutdown protects the device from overheating during prolonged high-power operation. This application is common in portable music players, headphones, and audio interfaces.
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推荐产品汇总
工程参考数据： LD1117S50TR ——对比、设计指导和合规信息。
选型指南
与替代料对比
| 参数 | 本产品 | LD1117S33TR | AMS1117-5.0 | NCP1117ST50T3G |
|---|---|---|---|---|
| Package | SOT-223 | SOT-223 | SOT-223 | SOT-223 |
| Brand | STMicroelectronics | STMicroelectronics | Advanced Monolithic Systems | onsemi |
| Output Voltage | 5.0V | 3.3V | 5.0V | 5.0V |
| Maximum Output Current | 800mA | 800mA | 1A | 1A |
| Dropout Voltage | 1.1V at 800mA | 1.1V at 800mA | 1.1V at 800mA | 1.1V at 800mA |
| Quiescent Current | 5mA | 5mA | 5mA | 5mA |
| Input Voltage Range | 6.5V to 15V | 6.5V to 15V | 6.5V to 15V | 6.5V to 15V |
| RoHS Compliant | Yes | Yes | Yes | Yes |
关键差异点
- Low dropout voltage of 1.1V at 800mA （对比 AMS1117-5.0)
- Fixed 5V output with 800mA capability （对比 LD1117S33TR)
- Wide input voltage range of 6.5V to 15V （对比 NCP1117ST50T3G)
设计说明
The LD1117S50TR in SOT-223 package has a junction-to-ambient thermal resistance of 50°C/W. At maximum output current of 800mA and a typical dropout of 1.1V, the power dissipation is approximately 0.88W, resulting in a temperature rise of 44°C above ambient. For reliable operation, ensure adequate copper area on the PCB connected to the exposed tab. For ambient temperatures above 70°C, consider derating the output current or adding a heatsink.
Place input and output capacitors as close to the LD1117S50TR pins as possible. A 10uF ceramic capacitor on the input and a 10uF ceramic capacitor on the output are recommended for stability. The output capacitor must have an ESR in the range of 0.1 to 10 ohms for stable operation. Connect the exposed tab to a large copper pour to enhance thermal dissipation.
Do not exceed the maximum input voltage of 15V. Ensure the input voltage is at least 6.5V to maintain regulation. The LD1117S50TR is not designed for parallel operation; do not connect multiple regulators in parallel to increase output current. Also, avoid using the device in applications that require AEC-Q100 qualification, as it is not automotive-grade.
合规信息
RoHS compliant per STMicroelectronics product page. Not AEC-Q100 qualified. Lead-free per datasheet.
