L7986A - 3A 61V Step-Down Switching Regulator | STMicroelectronics
MPN： L7986A ✓ 啟用中L7986A 概覽
A step-down switching regulator, also known as a buck converter, is a type of DC-DC converter that steps down a higher input voltage to a lower output voltage with high efficiency. Unlike linear regulators, which dissipate excess power as heat, switching regulators use an inductor and a switch to transfer energy in discrete packets, achieving efficiencies often above 90%. The L7986A belongs to the family of power management ICs, specifically DC-DC converters, which are essential in systems requiring voltage conversion with minimal power loss.
Key features of the L7986A include a 250kHz fixed switching frequency, an internal compensation network, and a power-good (PGOOD) open-drain output for monitoring output voltage status. The device also offers a soft-start function to limit inrush current during startup, and a thermal shutdown protection to prevent damage from overheating. The high input voltage capability of 61V makes it suitable for automotive and industrial applications where the supply rail can experience transients.
The L7986A uses a current-mode control architecture, which provides fast transient response and simplifies loop compensation. The internal high-side MOSFET has a low on-resistance of 250mOhm, reducing conduction losses and improving efficiency at high load currents. The device operates at a fixed 250kHz switching frequency, balancing efficiency and external component size. The HSOP-8 package with exposed pad ensures efficient heat dissipation, allowing the regulator to deliver full 3A output current without additional heatsinking in many applications.
Typical applications include automotive power supplies, industrial control systems, and distributed power architectures. In automotive systems, the wide input range accommodates 12V and 24V battery systems, while the high efficiency reduces thermal stress. In industrial settings, the regulator can step down 48V rails to lower voltages for logic and sensor circuits. The PGOOD output simplifies power sequencing in multi-rail systems.
When designing with the L7986A, ensure proper PCB layout with short, wide traces for high-current paths and adequate copper area for the exposed pad to dissipate heat. The input and output capacitors should be placed close to the IC to minimize parasitic inductance. The soft-start capacitor value determines the startup time and inrush current, which should be selected based on the load requirements.
直接替換替代品，適用於 L7986A — 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： L7986A （相同外形與佔位） — 差異在於 Input Voltage Range, Operating Temperature Range, Output Voltage Range, Package, Switching Frequency.
L7986ATR
✅ 直接替換📋 參考替代品（不在目錄中）
L7986TR
✅ 直接替換聯絡詢價
查看資料表 →L7987A
✅ 直接替換 ⚠️ 規格未經驗證📋 參考替代品（不在目錄中）
TPS54360
✅ 直接替換 ⚠️ 規格未經驗證📋 參考替代品（不在目錄中）
LT8610
✅ 直接替換 ⚠️ 規格未經驗證📋 參考替代品（不在目錄中）
L7986A 最大額定值與電氣特性
| 輸入電壓範圍 | 4.5 V to 61 V |
| 輸出電壓範圍 | 0.6 V to VIN |
| 最大輸出電流 | 3 A |
| 切換頻率 | 250 kHz |
| 高側 MOSFET 導通電阻 | 250 mOhm |
| 參考電壓 | 0.6 V |
| 靜態電流 | 2.5 mA |
| Shutdown Supply Current | 10 uA |
| Soft-Start Time | 1 ms (typical) |
| 過熱關機 | Yes |
| 工作溫度範圍 | -40C to +150C |
| 封裝 | HSOP-8 |
| 安裝類型 | Surface Mount |
| RoHS 狀態 | Compliant |
| PGOOD Output | Open-drain |
L7986A 腳位配置
| 腳位 1 | SW — Switch node output |
| 腳位 2 | GND — Ground |
| 腳位 3 | FB — Feedback input |
| 腳位 4 | EN — Enable input |
| 腳位 5 | PGOOD — Power good output |
| 腳位 6 | VCC — Supply voltage |
| 腳位 7 | VIN — Input voltage |
| 腳位 8 | GND — Ground |
典型應用
L7986A 適用於 6 應用s: Automotive Power Supplies, Industrial Control Systems, Distributed Power Architectures, Telecommunication Equipment, LED Lighting Systems, Test and Measurement Equipment.
Automotive Power Supplies
The L7986A is ideal for automotive power supplies due to its wide input voltage range of 4.5V to 61V, which accommodates 12V and 24V battery systems and handles voltage transients. Its high efficiency reduces heat dissipation in the engine compartment. In a typical automotive application, the L7986A steps down the battery voltage to 5V or 3.3V for microcontrollers, sensors, and infotainment systems. The PGOOD output ensures proper power sequencing for safety-critical systems. The device's thermal shutdown protection prevents damage during over-temperature conditions, which is crucial in high-temperature automotive environments.
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Industrial Control Systems
In industrial control systems, the L7986A steps down 24V or 48V rails to lower voltages for logic circuits, sensors, and actuators. Its wide input range and high efficiency make it suitable for factory automation and process control. The fixed 250kHz switching frequency allows for a compact design with small external components. The soft-start feature limits inrush current, protecting the input supply and downstream components. The device's operating temperature range of -40C to +150C ensures reliable operation in harsh industrial environments. The PGOOD output can be used to monitor the output voltage and trigger alarms or shutdown sequences if the voltage falls out of regulation.
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Distributed Power Architectures
The L7986A is well-suited for distributed power architectures where a central 48V bus is stepped down to various lower voltages at the point of load. Its high input voltage capability and 3A output current make it a versatile building block. In a typical design, the L7986A converts 48V to 12V for intermediate bus, then to 5V or 3.3V for logic. The high efficiency reduces power loss and simplifies thermal management. The device's internal compensation reduces external component count, saving board space. The PGOOD output enables power sequencing in multi-rail systems, ensuring that each rail comes up in the correct order.
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Telecommunication Equipment
In telecommunication equipment, the L7986A is used to step down 48V telecom rails to lower voltages for line cards, processors, and communication ICs. Its wide input range and high efficiency are critical for reducing power consumption in data centers and central offices. The device's low quiescent current of 2.5mA helps minimize standby power. The fixed 250kHz switching frequency is compatible with standard EMI filtering techniques, helping to meet EMC regulations. The thermal shutdown protection ensures reliable operation in densely packed equipment racks. The PGOOD output can be used for fault monitoring and system diagnostics.
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LED Lighting Systems
The L7986A can be used in LED lighting systems to step down a high input voltage to a constant current or voltage for LED drivers. Its high efficiency reduces heat generation, which is important for LED longevity. The wide input range allows it to operate from various supply voltages, including 12V, 24V, and 48V. The device's current-mode control provides good line and load regulation, ensuring consistent LED brightness. The soft-start feature prevents inrush current that could damage LEDs. The thermal shutdown protection safeguards the regulator in high-temperature lighting fixtures.
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Test and Measurement Equipment
In test and measurement equipment, the L7986A provides clean, regulated power for precision analog circuits. Its low output noise and high PSRR are essential for maintaining measurement accuracy. The wide input range allows it to operate from various bench supplies. The device's high efficiency reduces heat, which can affect measurement stability. The PGOOD output can be used to indicate when the output is stable, enabling automated test sequences. The soft-start feature prevents voltage overshoot that could damage sensitive components.
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推薦產品摘要
工程參考資料，適用於 L7986A — 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 | L7986ATR | L7986 | L7987A | TPS54360 | LT8610 |
|---|---|---|---|---|---|---|
| Package | HSOP-8 | HSOP-8 - same | HSOP-8 - same | HSOP-8 - same | HSOP-8 - same | HSOP-8 - same |
| Brand | STMicroelectronics | STMicroelectronics | STMicroelectronics | STMicroelectronics | Texas Instruments | Analog Devices |
| Input Voltage Range | 4.5V to 61V | 4.5V to 61V | 4.5V to 38V | 4.5V to 61V | 4.5V to 60V | 3.4V to 42V |
| Maximum Output Current | 3A | 3A | 3A | 4A | 3.5A | 2.5A |
| Switching Frequency | 250kHz | 250kHz | 250kHz | 250kHz | 100kHz to 2.5MHz | 200kHz to 2.2MHz |
| High-Side MOSFET On-Resistance | 250mOhm | 250mOhm | 250mOhm | 200mOhm | 92mOhm | 150mOhm |
| Quiescent Current | 2.5mA | 2.5mA | 2.5mA | 2.5mA | 146uA | 2.5uA |
| PGOOD Output | Yes | Yes | Yes | Yes | Yes | Yes |
主要差異化特點
- Wide input voltage range up to 61V (對比L7986)
- Higher output current than LT8610 (對比LT8610)
- Lower quiescent current than TPS54360 (對比TPS54360)
設計說明
For optimal performance, place the input capacitor (10uF) and output capacitor (22uF) as close to the VIN and SW pins as possible. Use short, wide traces for high-current paths to minimize parasitic inductance and resistance. The exposed pad should be connected to a large copper area for heat dissipation.
At 3A output with a 12V to 5V conversion, power dissipation is approximately 2.1W. The HSOP-8 package with exposed pad has a thermal resistance of about 40C/W, resulting in a temperature rise of 84C. Ensure adequate copper area or airflow to keep the junction temperature below 125C for reliable operation.
Do not exceed the absolute maximum input voltage of 61V. Ensure the feedback resistor divider uses 1% tolerance resistors to maintain output voltage accuracy. The soft-start capacitor value should be chosen to limit inrush current; a typical value of 10nF provides a 1ms soft-start time.
合規資訊
RoHS compliant per STMicroelectronics product page. Not AEC-Q100 qualified, but suitable for automotive applications per datasheet.
