LM2574M-5.0/NOPB - 0.5A Buck Regulator, 5V Fixed | Texas Instruments
料号： LM2574M-5.0/NOPB ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $2.97 | $2.97 |
| 10 | $2.59 | $25.90 |
| 100 | $2.07 | $207.00 |
| 500 | $1.74 | $870.00 |
| 1,000 | $1.49 | $1,490.00 |
LM2574M-5.0/NOPB 概述
What is a buck switching regulator? A buck converter is a switch-mode DC-DC power supply topology that steps a higher input voltage down to a lower regulated output voltage with high efficiency (typically 75-90%) by rapidly switching a power transistor and storing energy in an external inductor. Unlike a linear regulator, which burns the excess voltage as heat, a buck regulator pulses energy through an LC output filter, making it ideal when the input-to-output voltage differential is large or when thermal dissipation must be minimized.
Key features of the LM2574M-5.0/NOPB include a guaranteed 0.5 A output current, a fixed 5 V output (no external feedback resistors needed), a 52 kHz nominal switching frequency, ±4% output tolerance over line and load, internal current limiting, and thermal shutdown protection. Its wide 8 V to 40 V input range covers 12 V and 24 V industrial bus rails as well as automotive and telecom supply voltages. The 14-SOIC package with an exposed die-attach pad aids heat dissipation on standard 2 oz copper.
Architecturally, the LM2574 uses a voltage-mode PWM control loop with a fixed-frequency oscillator, a 1.235 V bandgap reference, and an internal NPN power switch. The high-gain error amplifier compares the divided output against the reference and modulates the switch duty cycle to maintain regulation. Its simple feedback and lack of compensation network requirements make it a popular choice for engineers transitioning away from LM78xx three-terminal linear regulators.
Typical applications include 12 V or 24 V industrial sensor power, automotive accessory subsystems, point-of-load regulation for microcontrollers and logic, battery chargers for lead-acid or Li-ion stacks, and small appliance or HVAC control boards. The 5 V fixed output is a particularly common rail for 5 V MCUs, transceivers, and logic.
When designing with this part, observe the catch-diode reverse-voltage and current ratings, choose an inductor with a saturation current at least 1.3× the regulator's switch current limit, and place input/output capacitors close to the IC. The fixed 52 kHz switching frequency allows use of small inductors and standard aluminum-electrolytic output capacitors.
This page synthesizes distributor pricing, drop-in same-package alternatives within the LM2574 family, and PCB layout guidance that complements the manufacturer datasheet.
直接替换替代料： LM2574M-5.0/NOPB ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
快速对比工具——选择替代料号进行并排对比：
LM2574MX-5.0/NOPB
✅ 直接替换📋 参考替代料（不在目录中）
LM2574HVM-5.0/NOPB
✅ 直接替换📋 参考替代料（不在目录中）
LM2574HVMX-5.0/NOPB
✅ 直接替换📋 参考替代料（不在目录中）
LM2574M-3.3/NOPB
✅ 直接替换📋 参考替代料（不在目录中）
LM2574M-12/NOPB
✅ 直接替换📋 参考替代料（不在目录中）
LM2574M-15/NOPB
✅ 直接替换📋 参考替代料（不在目录中）
LM2574M-5.0/NOPB 最大额定值与电气特性
| 拓扑 | Step-Down (Buck) |
| 输出类型 | Fixed |
| 输出电压 | 5 V |
| 最大输出电流 | 0.5 A |
| 输入电压范围 | 8 V to 40 V |
| Switching Frequency (typ.) | 52 kHz |
| PWM Type | Voltage Mode |
| 同步整流器 | No (external diode required) |
| 输出数量 | 1 |
| Output Voltage Tolerance | ±4% (line and load) |
| 工作温度 | -40C to +125C |
| 封装 | 14-SOIC (0.295" / 7.50 mm body width) |
| 安装类型 | Surface Mount |
| External Components Required | 4 (inductor, Cin, Cout, catch diode) |
| RoHS 状态 | Compliant |
LM2574M-5.0/NOPB 引脚配置
| 引脚 1 | VIN — Power input supply (8V to 40V) |
| 引脚 2 | OUTPUT — Switch node to external inductor |
| 引脚 3 | NC — Not connected (per datasheet) |
| 引脚 4 | GND — Ground reference |
| 引脚 5 | NC — Not connected (per datasheet) |
| 引脚 6 | FEEDBACK — Output voltage sense (fixed 5V internally trimmed) |
| 引脚 7 | NC — Not connected (per datasheet) |
| 引脚 8 | ON/OFF — Active-high enable input |
| 引脚 9 | NC — Not connected (per datasheet) |
| 引脚 10 | NC — Not connected (per datasheet) |
| 引脚 11 | NC — Not connected (per datasheet) |
| 引脚 12 | NC — Not connected (per datasheet) |
| 引脚 13 | NC — Not connected (per datasheet) |
| 引脚 14 | NC — Not connected (per datasheet) |
典型应用
LM2574M-5.0/NOPB 适用于 6 应用s: Industrial 24V Sensor Power Supply, Automotive Accessory and Body Electronics, Point-of-Load 5V for MCUs and Logic, Battery Charger Auxiliary Supply, Appliance and HVAC Control Boards, Retrofit Replacement for LM78xx Linear Regulators.
Industrial 24V Sensor Power Supply
The LM2574M-5.0/NOPB converts a 24V industrial bus rail down to a clean 5V at 0.5A for PLC sensor modules, 4-20mA loop transmitters, and factory-floor microcontrollers. Its 8V to 40V input range tolerates 24V bus transients and brownouts, while the 52 kHz switching frequency stays clear of the 4-20mA signal band. The fixed 5V output eliminates feedback resistor drift that would otherwise degrade analog accuracy over temperature in industrial sensor signal chains. The 14-SOIC footprint allows integration into compact DIN-rail module PCBs with standard 2 oz copper and no heatsink at typical 100-300 mA loads.
推荐
Automotive Accessory and Body Electronics
The LM2574M-5.0/NOPB is well-suited to automotive body and accessory subsystems operating from a 12V or 24V battery rail, such as interior lighting controllers, seat-control modules, and infotainment auxiliary supplies. Its 40V max input handles 24V jump-start and 36V load-dump transients, while the 0.5A current rating covers most small actuator and LED-driver rails. The ±4% line/load regulation keeps 5V microcontrollers and CAN transceivers within spec across cold-crank and cranking events. The wide -40C to +125C operating temperature range meets under-hood and cabin electronics automotive-grade environmental requirements.
推荐
Point-of-Load 5V for MCUs and Logic
The LM2574M-5.0/NOPB provides a local 5V, 0.5A point-of-load rail for microcontroller, ASIC, and logic subsystems on multi-rail boards. Compared to a linear 7805, the buck topology achieves 80-85% efficiency, eliminating the 0.7-1.0W of heat a 7805 would dissipate at 24VIN. This allows placement of the regulator right next to the MCU on dense PCBs without thermal vias or copper pours. The 14-SOIC surface-mount package is ideal for reflow assembly and supports automated optical inspection. The internal 52 kHz oscillator requires no external frequency-setting components.
推荐
Battery Charger Auxiliary Supply
The LM2574M-5.0/NOPB supplies a regulated 5V, 0.5A auxiliary rail for battery management and charger circuits in lead-acid, Li-ion, and supercapacitor backup systems. Its high-side NPN switch and 8V-40V input directly accept multi-cell battery stacks (12V/24V/36V nominal) and tolerate charger bulk-voltage excursions. The 5V rail powers BMS controllers, gas-gauge ICs, balancing MOSFETs, and communication interfaces. Compared to a linear regulator, the buck design extends battery runtime by reducing quiescent losses, especially important in solar-powered and always-on backup applications.
推荐
Appliance and HVAC Control Boards
The LM2574M-5.0/NOPB is widely used in white goods, HVAC thermostats, and small appliance control boards to step a 12V or 24V rectified mains rail down to a stable 5V supply for the main controller, display, and wireless module. The 0.5A output covers typical MCU + Wi-Fi/BLE module + relay-driver loads. The four-external-component design (inductor, two caps, diode) keeps BOM cost and assembly time low for high-volume consumer products. The fixed-frequency operation simplifies EMI compliance to FCC and EN 55015 radiated-emission standards for household appliances.
推荐
Retrofit Replacement for LM78xx Linear Regulators
The LM2574M-5.0/NOPB is the canonical retrofit for LM7805/LM7812 three-terminal linear regulators when thermal dissipation must be reduced. The trade-off is footprint: the LM2574 requires a 14-SOIC land pattern plus an external inductor and Schottky diode, instead of the LM78xx's TO-220. In return, efficiency rises from 35-40% to 75-85%, which is the difference between needing a heatsink and running cold at typical loads. The 0.5A continuous rating covers the same applications as a 7805 with proper derating, and the ±4% line/load regulation is comparable.
推荐
推荐产品汇总
工程参考数据： LM2574M-5.0/NOPB ——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 | LM2574MX-5.0/NOPB | LM2574HVM-5.0/NOPB | LM2574HVMX-5.0/NOPB | LM2574M-3.3/NOPB | LM2574M-12/NOPB | LM2574M-15/NOPB |
|---|---|---|---|---|---|---|---|
| Package | 14-SOIC (0.295", 7.50 mm) | 14-SOIC (0.295", 7.50 mm) - same | 14-SOIC (0.295", 7.50 mm) - same | 14-SOIC (0.295", 7.50 mm) - same | 14-SOIC (0.295", 7.50 mm) - same | 14-SOIC (0.295", 7.50 mm) - same | 14-SOIC (0.295", 7.50 mm) - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Output Voltage | 5 V | 5 V (same) | 5 V (same) | 5 V (same) | 3.3 V | 12 V | 15 V |
| Input Voltage Range | 8 V to 40 V | 8 V to 40 V | 8 V to 60 V (HV) | 8 V to 60 V (HV) | 8 V to 40 V | 8 V to 40 V | 8 V to 40 V |
| Output Current | 0.5 A | 0.5 A | 0.5 A | 0.5 A | 0.5 A | 0.5 A | 0.5 A |
| Switching Frequency (typ.) | 52 kHz | 52 kHz | 52 kHz | 52 kHz | 52 kHz | 52 kHz | 52 kHz |
| Topology / Synchronous Rectifier | Buck, external diode | Buck, external diode | Buck, external diode | Buck, external diode | Buck, external diode | Buck, external diode | Buck, external diode |
| Standard Reel Qty | 1,000 (M suffix) | 2,500 (MX suffix) | 1,000 (M suffix) | 2,500 (MX suffix) | 1,000 (M suffix) | 1,000 (M suffix) | 1,000 (M suffix) |
关键差异点
- Higher input voltage tolerance than base LM2574M family （对比 LM2574HVM-5.0/NOPB)
- Drop-in compatibility across fixed 3.3V/5V/12V/15V outputs （对比 LM2574M-3.3/NOPB)
- Factory-trimmed 5V output eliminates external feedback resistors （对比 LM2574M-ADJ/NOPB)
- Higher reel quantity for OEM production （对比 LM2574MX-5.0/NOPB)
设计说明
Estimated: at VIN=24V, VOUT=5V, IOUT=0.5A, the LM2574M-5.0/NOPB dissipates roughly (24-5)*0.5/η ≈ 1.5W of internal switching loss. Choose a Schottky catch diode (e.g. B340A or SS34) with reverse voltage ≥ 1.5× VIN_max and average forward current ≥ 1A. Place the input bulk capacitor (≥ 100 µF, 50V electrolytic) within 1 cm of the VIN pin to suppress input ripple and ringing.
Estimated: the 14-SOIC package has θJA of approximately 80-90 C/W on standard JEDEC 1 oz 2-layer board, meaning 1.5W of dissipation raises the junction temperature 120-135C above ambient. At TA=+25C, the die temperature stays within the -40C to +125C operating range; at TA=+85C industrial ambient, attach the exposed die-attach pad to a copper pour of at least 1 square inch (645 mm²) to keep TJ below +125C.
Keep the catch diode and the input capacitor loop area as small as possible. The high di/dt loop includes VIN, the internal switch, the catch diode, and ground - minimize this loop to reduce conducted and radiated EMI at the 52 kHz fundamental and its harmonics. Place the output capacitor close to the inductor and load return point; use a 220 µF to 470 µF low-ESR aluminum electrolytic for minimum output ripple (typically 30-50 mV pp at full load).
Do not operate the LM2574M-5.0/NOPB below 8V input - the internal NPN switch saturates and regulation collapses. Do not leave the ON/OFF pin floating: tie it to VIN through a 10 kΩ resistor for always-on operation, or drive it with an open-drain / open-collector control signal. Avoid using a standard 1N400x rectifier as the catch diode - its slow reverse recovery kills efficiency and can damage the switch; always use a Schottky.
Route the FEEDBACK trace away from the OUTPUT switch node to avoid noise injection. Use a small ground plane tied to pin 4, and connect the input cap, output cap, and catch-diode ground returns to the same ground star-point. For multi-layer boards, place a continuous ground plane under the regulator to shield analog signals and provide a low-impedance thermal path.
合规信息
RoHS compliant per TI product page (NOPB suffix). Not AEC-Q100 qualified - this is an industrial-grade part. For AEC-Q100 automotive-grade buck regulators, consider TPS54xxx or LM4360x families. Lead-free (Pb-free) per NOPB designation; non-NOPB version is lead-containing.
