LM7812L-TA3-T - 12V 1A Fixed LDO Regulator, TO-220 | UTC
MPN： LM7812L-TA3-T ✓ 啟用中LM7812L-TA3-T 概覽
A linear regulator - and the 78xx family specifically - is a type of power-management IC that drops a higher DC input voltage down to a fixed, regulated lower DC output voltage using a pass transistor and on-chip bandgap reference. In the broader system hierarchy, the LM7812 sits below switching converters in efficiency but excels in simplicity, low noise, and zero EMI, which is why it remains a default choice for analog rails, op-amp supplies, relay coils, fan drivers, and microcontroller peripheral power.
Key specifications include a typical output voltage of 12V (regulated to within approximately +/-4% across line, load, and temperature), 1A continuous output current, a quiescent current of 8 mA, ripple rejection of 72 dB at 120 Hz, and an output noise floor of approximately 75 uV. The TO-220 package provides a tab that can be soldered or clipped to a PCB copper pour or external heatsink, supporting reliable operation at the upper end of the input-voltage and load-current range.
The regulator uses a series NPN pass element with on-chip bandgap reference and error amplifier, providing closed-loop regulation without external feedback components. Its 72 dB ripple rejection at 120 Hz effectively attenuates rectified mains hum and downstream switching noise from upstream converters.
Typical applications include 12V power rails for op-amps, relays, fans, LED drivers, motor drivers, microcontroller peripherals, and hobby robotics. The wide input range also supports industrial 24V systems with adequate headroom and 12V battery-powered equipment such as lead-acid battery stacks.
When designing with this device, calculate power dissipation as (VIN - VOUT) x IOUT and ensure the TO-220 tab is heatsinked when dissipation exceeds approximately 1.5W. A minimum 0.33 uF input capacitor and 0.1 uF output capacitor are recommended for stability, per the UTC datasheet.
This page synthesizes distributor pricing, drop-in alternatives across multiple manufacturers, and practical design notes not found in the standalone manufacturer datasheet, enabling engineers to source and qualify the LM7812L-TA3-T with confidence.
直接替換替代品，適用於 LM7812L-TA3-T — 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。
此系列的變體
與下列產品可直接替換的同系列型號： LM7812L-TA3-T （相同外形與佔位） — 差異在於 Dropout Voltage, Input Voltage Range, Package, Regulator Type.
LM7812CT
✅ 直接替換 ⚠️ 規格未經驗證📋 參考替代品（不在目錄中）
LM7812L-TF3-T
✅ 直接替換📋 參考替代品（不在目錄中）
LM7805L-TA3-T
✅ 直接替換聯絡詢價
查看資料表 →MC7812CTG
✅ 直接替換📋 參考替代品（不在目錄中）
L7812CV
✅ 直接替換📋 參考替代品（不在目錄中）
LM340-12
✅ 直接替換📋 參考替代品（不在目錄中）
LM7812L-TA3-T 最大額定值與電氣特性
| Regulator Type | Standard Fixed Positive Linear Regulator (LDO family) |
| Output Polarity | Positive |
| Output Voltage Type | Fixed |
| Nominal Output Voltage | 12 V |
| 最大輸出電流 | 1 A |
| 輸入電壓範圍 | 14.5 V to 35 V |
| 壓降電壓 | 2 V (typical) |
| 靜態電流 | 8 mA (typical) |
| Ripple Rejection (PSRR) | 72 dB at 120 Hz |
| 輸出雜訊 | 75 uV (typical) |
| 工作接面溫度 | -20 C to +125 C |
| 過熱關機 | Internal (Over-Temperature Protection) |
| 電流限制 | Internal Over-Current Protection |
| 封裝 | TO-220, 3-pin (TA3-T = TO-220 lead-formed, lead-free, tape packing) |
| 安裝類型 | Through-Hole |
| Lead Finish | Lead Free (per UTC datasheet) |
| Lifecycle Stage | Active |
| RoHS 狀態 | Compliant (per JLCPCB listing) |
LM7812L-TA3-T 腳位配置
| 腳位 1 | VIN — Input voltage (14.5V to 35V) |
| 腳位 2 | GND — Ground (also connected to metal tab) |
| 腳位 3 | VOUT — Regulated 12V output |
典型應用
LM7812L-TA3-T 適用於 6 應用s: 12V Relay and Solenoid Driver Power Supply, Op-Amp and Analog Circuit 12V Rail, DC Fan and Brushless Motor Power, Microcontroller and Logic Peripheral Power, 12V LED Strip and Lighting Driver, 12V Lead-Acid Battery Charger (Float Mode).
12V Relay and Solenoid Driver Power Supply
The LM7812L-TA3-T's 12V output and 1A current capability make it well suited to power 12V automotive-style relays, solenoid valves, and switching actuators in industrial control panels. With a typical coil current of 50-200 mA per relay, the regulator comfortably drives 4-8 relay coils simultaneously while maintaining a stable 12V rail across the 24V industrial input bus. Its internal over-current protection and thermal shutdown provide robust fault tolerance when downstream wiring faults occur.
推薦
Op-Amp and Analog Circuit 12V Rail
The LM7812L-TA3-T provides a clean 12V rail for dual op-amp circuits such as the TL082, LM358, or NE5532 in audio preamplifier, instrumentation, and signal-conditioning applications. Its 72 dB ripple rejection at 120 Hz effectively attenuates rectified mains hum, while the absence of high-frequency switching noise keeps the rail quiet for low-level analog signals. The 1A current rating supports multi-op-amp circuits and small buffer stages without additional regulation.
推薦
DC Fan and Brushless Motor Power
The LM7812L-TA3-T's 1A continuous output current makes it a good fit for powering 12V DC cooling fans, small brushless motors, and PC-style PWM fans used in 3D printers, CNC machines, and electronics enclosures. The fixed 12V output allows fan operation without additional PWM drive circuitry, and the wide 14.5V-35V input range accepts 24V industrial rails or rectified 18VAC transformer outputs. A bypass capacitor on the output reduces motor commutator noise back into the rail.
推薦
Microcontroller and Logic Peripheral Power
The LM7812L-TA3-T supplies 12V to microcontroller peripheral circuitry such as RS-232 line drivers (MAX232), LCD bias generators, sensor excitation, and analog signal-conditioning front-ends in 5V MCU systems. The 12V rail provides ample headroom for op-amp dual-supply generation via ICL7660 or LT1054 charge pumps. The internal thermal protection prevents catastrophic failure during sustained overload conditions, making it reliable in unattended industrial installations.
推薦
12V LED Strip and Lighting Driver
The LM7812L-TA3-T powers 12V LED strips, automotive interior lighting, and signage modules that draw up to 1A total (approximately 5 meters of standard 5050 LED strip). The fixed 12V output matches the typical LED strip forward-voltage requirement, eliminating the need for constant-current LED drivers. Its 72 dB PSRR keeps the LED brightness steady even when upstream 24V supplies sag under transient loads, and thermal shutdown protects against short-circuit faults.
推薦
12V Lead-Acid Battery Charger (Float Mode)
The LM7812L-TA3-T can serve as a simple float charger for 12V lead-acid batteries when paired with current-limiting resistors, providing a regulated 12V rail at up to 1A. This is a low-cost charging solution for backup battery systems, emergency lighting, and small UPS applications. The thermal shutdown and current limit protect the regulator from overload during deeply discharged battery recovery. A series resistor sets the float current, while a reverse-biased Schottky diode prevents discharge through the regulator.
推薦
推薦產品摘要
工程參考資料，適用於 LM7812L-TA3-T — 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 | LM7812CT | LM7812L-TF3-T | LM7805L-TA3-T | MC7812CTG | L7812CV | LM340-12 |
|---|---|---|---|---|---|---|---|
| Package | TO-220 (TA3-T) | TO-220 | TO-220 | TO-220 | TO-220 | TO-220 | TO-220 |
| Brand | Unisonic Technologies | Unisonic Technologies | Unisonic Technologies | Unisonic Technologies | onsemi | STMicroelectronics | Texas Instruments |
| Output Voltage | 12 V | 12 V | 12 V | 5 V | 12 V | 12 V | 12 V |
| Maximum Output Current | 1 A | 1 A | 1 A | 1 A | 1 A | 1.5 A | 1 A |
| Input Voltage Range | 14.5 V to 35 V | 14.5 V to 35 V | 14.5 V to 35 V | 7 V to 35 V | 14.5 V to 35 V | 14.5 V to 35 V | 14.5 V to 35 V |
| Dropout Voltage | 2 V (typical) | 2 V | 2 V | 2 V | 2 V | 2 V | 2 V |
| Quiescent Current | 8 mA | 8 mA | 8 mA | 8 mA | 8 mA | 8 mA | 8 mA |
| Ripple Rejection (PSRR) | 72 dB at 120 Hz | 72 dB at 120 Hz | 72 dB at 120 Hz | 72 dB at 120 Hz | 72 dB at 120 Hz | 72 dB at 120 Hz | 72 dB at 120 Hz |
| Unit Price (qty 1, USD) | $0.1193 | ~$0.12 | ~$0.12 | ~$0.12 | ~$0.45 | ~$0.60 | ~$1.20 |
主要差異化特點
- Lowest-cost 12V TO-220 regulator in the 78xx family at LCSC (對比MC7812CTG (onsemi))
- Wider sourcing availability in Asia-Pacific channel (對比L7812CV (STMicroelectronics))
- Same TO-220 footprint as TI LM340-12 with lower BOM cost (對比LM340-12 (Texas Instruments))
設計說明
Estimated: At VIN=24V, VOUT=12V, IOUT=1A, power dissipation is (24-12)*1 = 12W. With TO-220 junction-to-ambient thermal resistance of approximately 50 C/W without heatsink, Tj rise is 600 C above ambient - clearly requiring a heatsink. As a rule of thumb, attach a TO-220 clip-on heatsink (thermal resistance 10-20 C/W) whenever dissipation exceeds 1.5W to keep Tj below 125 C. A minimum 100 sq cm of PCB copper pour also provides significant heatsinking.
Per the UTC LM78XX datasheet, place a 0.33 uF ceramic or tantalum input capacitor close to the VIN pin and a 0.1 uF ceramic output capacitor close to the VOUT pin to ensure stability. Long input leads (without input capacitance) can cause oscillation when the source impedance is high, especially with a transformer-rectified supply. For applications with long wiring or inductive loads, add a 1N4007 reverse-biased diode from VOUT to VIN to protect the regulator from reverse voltage transients.
Do not exceed 35V input voltage - the regulator will go into over-voltage stress and may trigger thermal shutdown or fail. The metal tab of the TO-220 package is internally connected to GND (pin 2); when mounting to a heatsink with thermal compound, ensure the heatsink is also grounded or use a mica/thermal pad insulator if the heatsink is at a different potential. Bypass the regulator with the recommended 0.33 uF input and 0.1 uF output capacitors even if the supply appears clean - high-frequency stability depends on local decoupling.
合規資訊
RoHS compliance and lead-free status confirmed via JLCPCB listing. AEC-Q100 not applicable for this through-hole linear regulator. REACH, halogen-free, and conflict-minerals status not explicitly stated in UTC datasheet - mark as 'unknown' until verified.
