LD1117S25TR - 800mA Low Dropout Positive Regulator | STMicroelectronics
料号： LD1117S25TR ✓ 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 |
LD1117S25TR 概述
A low dropout regulator (LDO) is a type of linear voltage regulator that maintains a stable output voltage even when the input voltage is only slightly higher than the output. Unlike standard linear regulators, LDOs achieve a low dropout voltage by using a PNP pass transistor or a PMOS device, allowing them to operate efficiently in applications where the input-to-output voltage difference is small. LDOs are a subset of linear regulators, which in turn are part of the broader category of voltage regulators within power management integrated circuits (ICs).
Key features of the LD1117S25TR include a fixed 2.5V output, a maximum output current of 800mA, and a dropout voltage of 1.1V at full load. The device also offers internal current limiting and thermal shutdown protection, ensuring safe operation under fault conditions. The SOT-223 package provides a compact footprint with a thermal resistance of approximately 50°C/W, enabling moderate power dissipation without external heatsinking.
The LD1117S25TR utilizes a PNP pass transistor architecture, which allows for low dropout operation and stable output with a minimum output capacitor of 10µF. The device is designed to be stable with tantalum or aluminum electrolytic capacitors, and it includes a bandgap reference for accurate output voltage regulation. The internal current limit and thermal shutdown circuits protect the device from overcurrent and overtemperature conditions, enhancing system reliability.
Typical applications for the LD1117S25TR include post-regulation for switching power supplies, battery-powered equipment, and low-voltage logic supplies. Its fixed 2.5V output is commonly used to power microcontrollers, memory ICs, and other digital circuits that require a stable 2.5V rail. The low dropout voltage and low quiescent current make it suitable for portable devices where power efficiency is critical.
When designing with the LD1117S25TR, ensure that the input voltage is at least 1.1V above the output voltage to maintain regulation. The output capacitor should be placed close to the output pin to minimize parasitic inductance and ensure stability. Additionally, the thermal pad of the SOT-223 package should be connected to a copper area on the PCB to improve heat dissipation.
直接替换替代料： LD1117S25TR ——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： LD1117S25TR （相同外形与封装尺寸） ——差异在于 Output Voltage, Dropout Voltage, Input Voltage Range, Line Regulation, Load Regulation.
快速对比工具——选择替代料号进行并排对比：
LD1117S25TR
✅ 直接替换✓ 有现货
$0.18 / 个
查看数据手册 →LD1117S33TR
✅ 直接替换 ⚠️ 规格未核验✓ 有现货
$0.2 / 个
查看数据手册 →LD1117S18TR
✅ 直接替换 ⚠️ 规格未核验✓ 有现货
$0.15 / 个
查看数据手册 →AMS1117-2.5
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
NCP1117ST25T3G
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
AP1117-2.5
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
LD1117S25TR 最大额定值与电气特性
| 输出类型 | Fixed |
| 输出电压 | 2.5 V |
| 最大输出电流 | 800 mA |
| 输入电压范围 | Up to 15 V |
| 压差电压 | 1.1 V at 800 mA |
| 静态电流 | 5 mA |
| Line Regulation | 0.2% (typical) |
| Load Regulation | 0.4% (typical) |
| Output Capacitor | 10 µF (minimum) |
| 工作温度范围 | 0°C to +125°C |
| 封装 | SOT-223 |
| 安装类型 | Surface Mount |
| Thermal Resistance (θJA) | 50 °C/W |
| RoHS 状态 | Compliant |
| Lead-Free | Yes |
LD1117S25TR 引脚配置
| 引脚 1 | IN — Input voltage pin |
| 引脚 2 | GND — Ground pin |
| 引脚 3 | OUT — Regulated output voltage |
| 引脚 4 | TAB — Thermal pad, connected to OUT |
典型应用
LD1117S25TR 适用于 6 应用s: Post-Regulation for Switching Power Supplies, Battery-Powered Equipment, Low-Voltage Logic Supplies, Consumer Electronics, Industrial Control Systems, Telecommunication Equipment.
Post-Regulation for Switching Power Supplies
The LD1117S25TR is used as a post-regulator to provide a clean 2.5V rail from a noisy switching converter output. Its low dropout voltage of 1.1V allows it to operate with minimal headroom, and its 800mA output current is sufficient for many digital loads. The device's internal current limiting and thermal shutdown protect the downstream circuitry from faults. In a typical application, the LD1117S25TR is placed after a buck converter, with a 10µF output capacitor to ensure stability. The low output noise and good line/load regulation make it suitable for powering sensitive analog and digital circuits.
推荐
Battery-Powered Equipment
In battery-powered devices, the LD1117S25TR regulates a 2.5V rail from a battery voltage that may drop as low as 3.6V. Its low quiescent current of 5mA helps extend battery life, and the low dropout voltage ensures efficient operation even when the battery is nearly discharged. The SOT-223 package is compact, making it suitable for portable devices. The device's thermal shutdown prevents damage from excessive power dissipation, which is important in small enclosures. For a 3.7V Li-ion battery, the LD1117S25TR can provide a stable 2.5V output until the battery voltage falls below 3.6V.
推荐
Low-Voltage Logic Supplies
The LD1117S25TR provides a stable 2.5V supply for low-voltage logic ICs, such as FPGAs, CPLDs, and memory devices. Its 800mA output current can power multiple logic devices, and the fixed 2.5V output eliminates the need for external resistor dividers. The device's fast transient response ensures stable operation during rapid load changes. In a typical application, the LD1117S25TR is connected to a 3.3V rail, and the output is decoupled with a 10µF capacitor. The low dropout voltage allows the regulator to maintain regulation even if the 3.3V rail dips slightly.
推荐
Consumer Electronics
The LD1117S25TR is widely used in consumer electronics such as set-top boxes, routers, and gaming consoles to provide a clean 2.5V rail for various ICs. Its low cost and availability in the SOT-223 package make it a popular choice for high-volume production. The device's thermal shutdown and current limiting ensure reliable operation in consumer environments. In a typical application, the LD1117S25TR is powered from a 5V adapter, and the output is filtered with a 10µF capacitor. The low dropout voltage allows the regulator to operate efficiently even with a 5V input.
推荐
Industrial Control Systems
In industrial control systems, the LD1117S25TR provides a stable 2.5V reference for analog-to-digital converters (ADCs), sensors, and microcontrollers. Its wide input voltage range up to 15V allows it to be powered from industrial 24V buses with a pre-regulator. The device's low output noise and good line regulation ensure accurate measurements. In a typical application, the LD1117S25TR is used to power an ADC reference, with a 10µF output capacitor and a 0.1µF bypass capacitor for noise reduction. The device's thermal shutdown protects it from overtemperature conditions in harsh industrial environments.
推荐
Telecommunication Equipment
The LD1117S25TR is used in telecommunication equipment to provide a clean 2.5V rail for line drivers, transceivers, and digital signal processors. Its low dropout voltage and high output current make it suitable for powering multiple ICs. The device's low quiescent current is beneficial in always-on communication modules. In a typical application, the LD1117S25TR is powered from a 3.3V rail, and the output is decoupled with a 10µF capacitor. The device's thermal shutdown ensures reliable operation in equipment that may be exposed to high ambient temperatures.
推荐
推荐产品汇总
工程参考数据： LD1117S25TR ——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 | AMS1117-2.5 | NCP1117ST25T3G |
|---|---|---|---|---|
| Package | SOT-223 | SOT-223 | SOT-223 | SOT-223 |
| Brand | STMicroelectronics | STMicroelectronics | Advanced Monolithic Systems | onsemi |
| Output Voltage | 2.5V | 3.3V | 2.5V | 2.5V |
| Maximum Output Current | 800mA | 800mA | 1A | 1A |
| Dropout Voltage | 1.1V at 800mA | 1.1V at 800mA | 1.1V at 1A | 1.1V at 1A |
| Quiescent Current | 5mA | 5mA | 5mA | 5mA |
| Input Voltage Range | Up to 15V | Up to 15V | Up to 15V | Up to 15V |
| Operating Temperature Range | 0°C to +125°C | 0°C to +125°C | 0°C to +125°C | 0°C to +125°C |
关键差异点
- Fixed 2.5V output with 800mA current capability （对比 LD1117S33TR)
- Low dropout voltage of 1.1V at full load （对比 AMS1117-2.5)
- SOT-223 package with thermal pad （对比 NCP1117ST25T3G)
设计说明
The SOT-223 package has a thermal resistance of approximately 50°C/W. At maximum output current of 800mA and a dropout voltage of 1.1V, the power dissipation is 0.88W, resulting in a temperature rise of 44°C above ambient. Ensure adequate copper area on the PCB to dissipate heat, especially in high-temperature environments.
Place the input and output capacitors as close to the LD1117S25TR pins as possible. A minimum output capacitor of 10µF is required for stability, and a 0.1µF ceramic capacitor should be placed in parallel for high-frequency noise bypass. The thermal pad (tab) should be connected to a large copper area to improve heat dissipation.
Do not exceed the maximum input voltage of 15V. Ensure the input voltage is at least 1.1V above the output voltage to maintain regulation. The output capacitor must be placed close to the output pin to avoid instability. Use a capacitor with low ESR, such as a tantalum or aluminum electrolytic capacitor, as specified in the datasheet.
合规信息
RoHS compliant per STMicroelectronics product page. Not AEC-Q100 qualified. Lead-free and conflict minerals compliant.
