LM7805CT/NOPB - 5V 1.5A Linear Regulator TO-220 | Texas Instruments
MPN: LM7805CT/NOPB ✓ Hoạt độngLM7805CT/NOPB Tóm tắt
What is a linear voltage regulator? A linear voltage regulator (also called an LDO when dropout voltage is low, or simply a three-terminal regulator in the LM78xx case) is a power management IC that maintains a constant DC output voltage from a higher, possibly variable DC input. Unlike a switching DC-DC converter, a linear regulator dissipates the difference between VIN and VOUT as heat, so efficiency equals VOUT/VIN. The taxonomy: three-terminal regulator -> linear regulator -> voltage regulator -> power management IC -> semiconductor. The LM78xx family is the most widely used fixed-output linear regulator series in history, with billions of units shipped across industrial, consumer, and hobby markets.
Key features include 1.5 A peak output current, 5 V fixed output with typical +/-2% accuracy, 35 V maximum input voltage (per Mouser catalog listing), 2 V typical dropout, and internal thermal overload protection. The TO-220 package provides excellent thermal performance with a tab that can be soldered or screwed to a heatsink for continuous high-current operation.
The LM7805CT/NOPB uses a bipolar Darlington pass element with bandgap reference and on-chip resistor dividers. Its safe-area compensation allows momentary output shorts without damage, and the thermal shutdown circuit typically trips around 170 C junction temperature. Quiescent current is typically 5 mA and rises only slightly with load.
Typical applications include local 5 V regulation for digital logic (Arduino, microcontroller rails), USB charger / power-bank subsystems, hobby electronics, retrofit 5 V supplies in automotive 12 V systems, and as a quiet post-regulator after a switching converter to clean up ripple.
When designing, always check worst-case dissipation (P = (VIN(max) - 5 V) x IOUT(max)) and select a heatsink accordingly. A heatsink is required whenever P exceeds about 1.5 W in free air at 25 C ambient.
This page synthesizes distributor pricing, drop-in alternatives, and design notes not found in the manufacturer datasheet alone.
Bộ thay thế dễ dàng lắp đặt cho LM7805CT/NOPB — cùng gói, chân-to-chân tương thích. Các bộ phận yêu cầu hàn PCB bị loại trừ.
Các biến thể trong loạt này
Các mẫu cùng loạt có thể lắp đặt dễ dàng tương thích với LM7805CT/NOPB (cùng hình factor và footprint) — khác nhau ở Output Voltage Tolerance, Package, Maximum Output Current, Mounting Type, Output Voltage.
LM7805CT
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
LM78M05CT/NOPB
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
L7805CV
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →MC7805CTG
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
L7805CV
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →LM7805CT/NOPB Tỷ lệ tối đa & tính chất điện
| Regulator Type | Linear, Fixed Positive |
| Điện áp đầu ra | 5 V |
| Output Voltage Tolerance | +/-2% (typical) |
| Điện áp tối đa đầu ra | 1.5 A (peak) |
| Input Voltage Range (max) | 30 V (TI) / 35 V (Mouser listing) |
| Dropout Voltage (typical) | 2 V at 1 A |
| Quiescent Current (typical) | 5 mA |
| Line Regulation | 10 mV (typ) |
| Load Regulation | 25 mV (typ) |
| Nhiệt độ mối nối hoạt động | 0 C to +125 C |
| Kháng nhiệt, mối nối đến môi trường | 22.6 C/W (TO-220, typical) |
| Protection Features | Internal current limit, thermal shutdown, safe-area compensation |
| Hộp | TO-220-3 (NDE) |
| Kiểu lắp đặt | Through-hole (TAB also serves as heatsink tab) |
| Lead-Free / RoHS | Yes (NOPB suffix indicates lead-free, RoHS compliant) |
Cấu hình chân LM7805CT/NOPB
| Chân 1 | INPUT — Unregulated DC input (typically 7-30 V) |
| Chân 2 | GND — Common ground / 0 V reference |
| Chân 3 | OUTPUT — Regulated +5 V DC output |
Ứng dụng tiêu biểu
LM7805CT/NOPB phù hợp cho 6 Áp dụngs: Microcontroller & Arduino 5 V Rail, Retrofit Automotive 12 V to 5 V Supply, Post-Regulator After Switching Converter, USB Charger / Power Bank Subsystem, Hobby Electronics & Breadboard Power, Industrial Sensor & Actuator Power.
Microcontroller & Arduino 5 V Rail
The LM7805CT/NOPB is the classic 5 V rail regulator for Arduino Uno, Nano, and bare microcontroller boards (ATmega328P, PIC, STM32 'bluepill'). It drops a 7-12 V wall-adapter or battery input to a clean 5 V with +/-2% accuracy, 10 mV line regulation and 25 mV load regulation, sufficient for digital logic rails. The 1.5 A peak capability comfortably drives an ATmega328P plus a few LEDs and discrete peripherals. Unlike a switching regulator, the LM7805 adds no high-frequency ripple, which is helpful when the same board also hosts analog sensors. At 12 V input and 200 mA load, dissipation is about 1.4 W - a small clip-on heatsink is recommended for enclosed cases. The internal current limit and thermal shutdown protect the board if the output is accidentally shorted. Use a 0.33 uF input cap and 0.1 uF output cap as recommended by the LM78xx datasheet to ensure stability.
Được đề xuất
Retrofit Automotive 12 V to 5 V Supply
The LM7805CT/NOPB has been used for decades in automotive 12 V systems to derive 5 V for sensors, displays, microcontrollers, and aftermarket accessories. Nominal 13.8 V VIN with 5 V VOUT at 500 mA load dissipates about 4.4 W - the TO-220 tab and a small clip-on heatsink handle this comfortably. Cold-crank transients can drop VIN to 6-8 V, leaving only 1-3 V of headroom over the 2 V typical dropout; for cold-crank robustness, pair with a pre-boost or use an automotive-grade LDO. Load-dump transients up to 40 V require an external TVS clamp (e.g., 33 V SMAJ) on the input. The 1.5 A peak current handles brief inrush loads such as a relay coil or fan. Internal thermal shutdown and safe-area compensation protect the device if the output is shorted during wiring faults. The /NOPB suffix ensures RoHS compliance for OEM automotive modules.
Được đề xuất
Post-Regulator After Switching Converter
Cascading the LM7805CT/NOPB after a switching buck converter is a classic technique to obtain a clean, low-ripple 5 V rail from a higher-voltage intermediate bus. The switching converter handles the bulk voltage step-down efficiently (e.g., 24 V to 7 V), and the LM7805 drops the last 2 V linearly, removing all switching ripple and high-frequency noise. This topology is common in industrial PLCs and instrumentation where sensitive analog or RF circuits share a power bus with digital switching noise. The combined dissipation is split between the switcher and the linear regulator, keeping each within its SOA. The LM7805CT/NOPB's 5 mA quiescent current adds negligible overhead, and its 1.5 A peak handles transients beyond the linear stage's steady-state rating. Stability is maintained with the standard 0.33 uF input and 0.1 uF output capacitors.
Được đề xuất
USB Charger / Power Bank Subsystem
In low-cost USB charger and power bank designs, the LM7805CT/NOPB is often used to derive a clean 5 V rail from a 1S lithium cell boosted to 6-7 V, or directly from a higher-voltage wall adapter. The fixed 5 V output is well-suited to feed a downstream charging IC or a USB voltage regulator. The 1.5 A peak current supports 5 V / 1 A charging of smartphones and tablets. While efficiency is lower than a switching regulator at full VIN-VOUT delta (5 V / 7 V = 71% efficient), the simplicity of the LM7805 BOM (one IC, two caps, optional heatsink) keeps cost and PCB area minimal. For higher efficiency designs, a dedicated synchronous buck converter such as the LM3671 or TPS62840 is preferred, but the LM7805CT/NOPB remains a reliable fallback for cost-sensitive, lower-volume products.
Được đề xuất
Hobby Electronics & Breadboard Power
The LM7805CT/NOPB is a staple of hobbyist breadboards and educational kits. With three pins (IN, GND, OUT) and only two recommended bypass capacitors, it fits on any 0.1" spaced perfboard or breadboard. A 9 V battery or 9-12 V wall adapter powers any 5 V Arduino, Raspberry Pi (via 5 V rail), LED strip, or sensor cluster. The metal tab is also a convenient tie-point for a 5 V distribution rail on a solderless breadboard. Thermal behavior is forgiving at hobby currents (< 200 mA), so most breadboard builds run without a heatsink. The /NOPB suffix ensures lead-free compliance for school and competition projects. Drop-in compatibility with other 7805 variants means parts from any vendor work interchangeably.
Được đề xuất
Industrial Sensor & Actuator Power
In industrial 24 V systems, the LM7805CT/NOPB can drop 24 V down to 5 V to power logic-level sensors, isolated digital inputs, and low-power microcontroller nodes. At 24 V input and 200 mA load, dissipation is 3.8 W - a small TO-220 clip-on heatsink keeps the junction below 100 C in a 60 C ambient. For installations with long input lines subject to voltage transients and inductive kickback, a TVS clamp and input fuse protect the regulator. The internal safe-area compensation handles momentary output shorts from wiring faults, and thermal shutdown protects against sustained overload. The fixed 5 V output eliminates trim resistors, reducing calibration and field-failure modes. For higher-efficiency 24 V applications, a dedicated wide-Vin LDO such as the TPS7A4501 is preferred, but the LM7805CT/NOPB remains a low-cost, time-proven solution for non-isolated sensor nodes.
Được đề xuất
Tóm tắt các sản phẩm được đề xuất
Dữ liệu tham khảo kỹ thuật cho LM7805CT/NOPB — so sánh, hướng dẫn thiết kế và thông tin tuân thủ.
Hướng dẫn chọn lựa
So sánh với các sản phẩm thay thế
| Tham số | Sản phẩm này | LM7805CT | LM78M05CT/NOPB | L7805CV | MC7805CTG |
|---|---|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | STMicroelectronics | onsemi |
| Package | TO-220-3 (NDE) | TO-220-3 (NDE) - same | TO-220-3 - same | TO-220-3 - same | TO-220-3 - same |
| Output Voltage | 5 V | 5 V | 5 V | 5 V | 5 V |
| Output Current (peak) | 1.5 A | 1.5 A | 0.5 A | 1 A | 1 A |
| Maximum Input Voltage | 30 V | 30 V | 35 V | 35 V | 35 V |
| Dropout Voltage (typ) | 2 V | 2 V | 2 V | 2 V | 2 V |
| Quiescent Current (typ) | 5 mA | 5 mA | 4 mA | 5 mA | 5 mA |
| Lead-Free / RoHS | Yes (/NOPB) | No (legacy tin-lead) | Yes (/NOPB) | Yes | Yes |
Bảo phân biệt quan trọng
- Industry-standard drop-in availability across vendors (vsLM78M05CT/NOPB)
- 1.5 A peak current vs L7805CV's 1 A (vsL7805CV (STMicroelectronics))
- Lead-free /NOPB plating matches RoHS directives (vsLegacy LM7805CT (no NOPB))
- Three-pin simplicity vs switching regulator complexity (vsLM2591HVS-ADJ (switching))
Ghi chú thiết kế
Estimated: At VIN = 12 V, VOUT = 5 V, IOUT = 1 A, power dissipation is P = (12 - 5) x 1 = 7 W. With the TO-220 theta_JA of approximately 22.6 C/W in free air, the junction rises about 158 C above ambient - well beyond the 125 C rating. A clip-on heatsink (e.g., Fischer SK 104 with theta_SA around 8 C/W) or 100 sq cm of copper pours the junction temperature back into spec. Rule of thumb: any application with continuous P > 1.5 W in 25 C ambient requires a heatsink. The LM7805CT/NOPB thermal shutdown (typically 170 C) will protect the die but may cause output droop or system reset if it engages.
Always place a 0.33 uF (or larger) input capacitor close to the IN pin to GND, and a 0.1 uF output capacitor close to the OUT pin to GND. These capacitors ensure stability of the internal feedback loop and provide high-frequency bypassing for load transients. If the input source is more than a few inches away, use a larger input cap (e.g., 1-10 uF electrolytic) to handle the inrush. The TO-220 tab is electrically tied to the die substrate - usually grounded, but if left floating it picks up stray noise that can couple into the output. Solder the tab to a copper pour connected to GND for both thermal and electrical benefits.
Do not operate the LM7805CT/NOPB without input/output capacitors - the internal loop can oscillate and produce erratic output. Do not exceed 30 V VIN continuously (TI spec), even though legacy 78xx datasheets quote 35 V - this derating margin improves long-term reliability. Do not bypass the heatsink tab connection to GND on a high-current design - leaving it floating creates a leakage path and degrades thermal performance. Finally, do not use the LM7805CT/NOPB as a voltage dropper for high-current battery charging - the linear topology wastes too much power; use a switching charger IC instead.
Keep the input capacitor, regulator, and output capacitor in a tight linear layout with short, wide traces. The TO-220 tab is the primary thermal path - dedicate at least 1 sq inch of 2 oz copper pour (or 0.5 sq inch per watt of dissipation) and stitch vias to the bottom layer for through-hole designs. For surface-mount replacements, plan for the DPAK or TO-252 footprint instead. Avoid routing digital switching signals across the regulator's feedback traces (none here, but the IN/OUT traces can carry switching ripple from external loads).
Thông tin tuân thủ
The /NOPB suffix indicates lead-free plating per Texas Instruments' NOPB designation; the part is RoHS-compliant. Not AEC-Q100 qualified - for automotive designs requiring AEC-Q100, choose an automotive-grade LDO such as the TPS7A4501-Q1. Conflict-minerals compliance per TI's published CMRT.
