LM317LCPK - 100mA Adjustable Positive Regulator | Texas Instruments
MPN： LM317LCPK ✓ 啟用中LM317LCPK 概覽
A linear voltage regulator is a type of voltage regulator that maintains a constant output voltage by dissipating excess power as heat. The LM317L belongs to the broader family of positive adjustable linear regulators, alongside fixed-output regulators like the LM78xx series and modern low-dropout (LDO) regulators. As a linear regulator, it offers low output noise and fast transient response, but is less efficient than a switching regulator when the input-to-output differential is large.
Key features include the 100 mA output current, the wide 1.25V to 37V adjustable output, typical line regulation of 0.01%/V, and 30 uVrms output noise. Internal current limiting, safe-area compensation, and thermal overload protection are built in. The LM317LC series is characterized for a junction temperature range of 0C to +125C.
Technically, the LM317L uses a bandgap reference and an error amplifier. The output voltage follows the classic formula VOUT = 1.25V * (1 + R2/R1) + IADJ * R2, with a 1.25V reference and 50 uA adjustment pin current. Typical quiescent (adjustment pin) current is low, and the SOT-89-3 tab provides improved thermal dissipation versus SOT-23 packages.
Typical applications include on-board regulation for microcontrollers, analog sensor interfaces, low-power audio circuits, and battery-powered devices where a stable adjustable rail is required.
Design tip: maintain at least 3V input-to-output headroom, keep input and output capacitors close to the device, and solder the tab to a copper pour for heat dissipation at higher VIN-VOUT deltas.
直接替換替代品，適用於 LM317LCPK — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
LM317LIPK
✅ 直接替換📋 參考替代品（不在目錄中）
LM317KC
✅ 直接替換📋 參考替代品（不在目錄中）
LM317MT
✅ 直接替換📋 參考替代品（不在目錄中）
TL783
✅ 直接替換 ⚠️ 規格未經驗證📋 參考替代品（不在目錄中）
L200
✅ 直接替換 ⚠️ 規格未經驗證📋 參考替代品（不在目錄中）
LM317LCPK 最大額定值與電氣特性
| 輸出類型 | Adjustable |
| 輸出電壓範圍 | 1.25 V to 37 V |
| 最大輸出電流 | 100 mA |
| 輸入電壓範圍 | 3.75 V to 35 V |
| 輸出雜訊 | 30 uVrms |
| Line Regulation | 0.01%/V (typical) |
| 靜態電流 | 1.5 mA (typical) |
| Adjustment Pin Current | 50 uA (typical) |
| 熱阻 | 52 C/W (theta_JA) |
| 工作溫度 | 0C to +125C |
| 封裝 | SOT-89-3 (PK) |
| 安裝類型 | Surface Mount |
| RoHS 狀態 | Compliant |
LM317LCPK 腳位配置
| 腳位 1 | ADJ — Adjustment pin for setting output voltage |
| 腳位 2 | OUT — Regulated output voltage |
| 腳位 3 | IN — Input supply voltage |
典型應用
LM317LCPK 適用於 6 應用s: Microcontroller Power Supply, Analog Sensor Interface, Low-Power Audio Circuits, Battery-Powered Devices, Industrial Control Systems, Test and Measurement Equipment.
Microcontroller Power Supply
The LM317LCPK provides a stable adjustable voltage rail for microcontrollers, with 100mA output sufficient for most MCU boards. Its low noise (30 uVrms) ensures reliable operation of analog peripherals. The SOT-89-3 package is compact for space-constrained designs. Place input/output capacitors close to the device to maintain stability.
推薦
Analog Sensor Interface
The LM317LCPK is ideal for powering analog sensors that require a clean, adjustable supply. Its 30 uVrms noise and 0.01%/V line regulation minimize supply-induced errors in sensor readings. The adjustable output allows precise calibration of sensor bias voltages. Use a 10uF output capacitor to improve transient response.
推薦
Low-Power Audio Circuits
The LM317LCPK provides a low-noise supply for audio preamplifiers and headphone amplifiers. Its 30 uVrms noise is well below audible levels, and the adjustable output allows optimization of the operating point. The linear regulation avoids switching noise, preserving audio fidelity. Ensure adequate heat dissipation for higher input-output differentials.
推薦
Battery-Powered Devices
The LM317LCPK is suitable for battery-powered devices where a stable voltage is needed despite battery voltage variation. Its low quiescent current (1.5 mA) extends battery life, and the adjustable output allows matching the supply to the load requirements. For maximum efficiency, consider a switching regulator if the input-output differential is large.
推薦
Industrial Control Systems
The LM317LCPK provides a reliable adjustable supply for industrial control circuits, such as PLC I/O modules and sensor transmitters. Its wide input range (up to 35V) accommodates 24V industrial buses, and the thermal overload protection ensures safe operation. The SOT-89-3 package is robust for harsh environments.
推薦
Test and Measurement Equipment
The LM317LCPK is used in test equipment to provide a stable, adjustable reference voltage for calibration and measurement circuits. Its low noise and excellent line regulation ensure accurate readings. The adjustable output allows fine-tuning of reference levels. Use precision resistors for the adjustment network to maintain accuracy.
推薦
推薦產品摘要
工程參考資料，適用於 LM317LCPK — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 | LM317LIPK | LM317KC | LM317MT |
|---|---|---|---|---|
| Package | SOT-89-3 (PK) | SOT-89-3 (PK) - same | SOT-89-3 - same | SOT-89-3 - same |
| Brand | Texas Instruments | Texas Instruments | International Rectifier | Texas Instruments |
| Output Current | 100 mA | 100 mA | 100 mA | 100 mA |
| Output Voltage Range | 1.25V to 37V | 1.25V to 37V | 1.25V to 37V | 1.25V to 37V |
| Input Voltage Range | 3.75V to 35V | 3.75V to 35V | 3.75V to 35V | 3.75V to 35V |
| Output Noise | 30 uVrms | 30 uVrms | 30 uVrms | 30 uVrms |
| Operating Temperature | 0C to +125C | -40C to +125C | 0C to +125C | 0C to +125C |
| Quiescent Current | 1.5 mA | 1.5 mA | 1.5 mA | 1.5 mA |
主要差異化特點
- Wide temperature range option (對比LM317LIPK)
- Low output noise (對比LM317KC)
- Compact SOT-89-3 package (對比LM317T)
設計說明
The SOT-89-3 package has a thermal resistance of 52 C/W. At VIN=12V, VOUT=5V, and 100mA load, power dissipation is 0.7W, resulting in a 36.4C temperature rise. For higher dissipation, solder the tab to a larger copper pour or use a heatsink. Ensure the junction temperature stays within 0C to +125C.
Place input and output capacitors (typically 0.1uF and 1uF) as close to the device pins as possible. The adjustment pin should have a bypass capacitor (10uF) to improve ripple rejection. Use a ground plane to minimize noise and ensure stable operation.
Do not exceed the maximum input voltage of 35V. Maintain at least 3V input-to-output headroom for proper regulation. Use 1% or better resistors for the adjustment network to maintain output voltage accuracy. Avoid long traces to the adjustment pin to prevent noise pickup.
合規資訊
RoHS compliant per TI product page. Not AEC-Q100 qualified.
