LM3481QMMX/NOPBQ1 - 48V Boost/SEPIC/Flyback Controller | TI
料号： LM3481QMMX/NOPBQ1 ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $3.45 | $3.45 |
| 10 | $3.1 | $31.00 |
| 100 | $2.6 | $260.00 |
| 500 | $2.25 | $1,125.00 |
| 1,000 | $1.95 | $1,950.00 |
LM3481QMMX/NOPBQ1 概述
A switching controller is the brain of a switched-mode power supply (SMPS): it drives an external low-side N-FET as the primary switch, regulating the output through current-mode PWM control. As a controller (rather than a monolithic regulator), the LM3481-Q1 lets designers scale output power freely by choosing an external MOSFET, inductor, and sense resistor, making it suitable from a few watts up to tens of watts.
Key features include current-mode PWM control with 85% maximum duty cycle, programmable switching frequency (set by a single resistor, up to 1MHz) enabling small magnetics and fast transient response, an internal 5V regulated gate-driver rail for the external N-FET, cycle-by-cycle current limit, thermal shutdown, and a frequency-foldback/soft-start-friendly architecture that simplifies startup in boost applications. Wide 2.97V to 48V VIN supports automotive 12V and 24V rails with load-dump headroom.
The LM3481-Q1 is fabricated on a proven analog process, qualified to AEC-Q100 Grade 1 (-40C to +125C ambient), making it suitable for under-hood and in-cabin automotive systems. The VSSOP-10 package has a low profile of 1mm and small footprint for space-constrained designs. Output voltage is set by a feedback divider; the FB reference threshold is specified in the datasheet.
Typical applications include automotive LED headlamp and backlight drivers, on-board charger auxiliary supplies, infotainment display boost rails, industrial 24V-to-higher-voltage boost converters, and isolated or non-isolated flyback auxiliaries.
Design tip: keep the switch-node and gate-drive loops tight, and size the current-sense resistor for the desired cycle-by-cycle limit while accounting for its power dissipation.
直接替换替代料： LM3481QMMX/NOPBQ1 ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
本系列中的变体
可与以下型号直接替换的同系列型号： LM3481QMMX/NOPBQ1 （相同外形与封装尺寸） ——差异在于 Package, RoHS Status, Topology.
快速对比工具——选择替代料号进行并排对比：
LM3481QMM/NOPB
✅ 直接替换📋 参考替代料（不在目录中）
LM3481MMX/NOPB
✅ 直接替换✓ 有现货
$0.9 / 个
查看数据手册 →LM3481QMY/NOPB
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
LM5117QMHX/NOPB
⚡ 相同封装✓ 有现货
$3.72 / 个
查看数据手册 →MAX668AUB
⚡ 相同封装 ⚠️ 规格未核验📋 参考替代料（不在目录中）
LM3481QMMX/NOPBQ1 最大额定值与电气特性
| 拓扑 | Boost, SEPIC, Flyback |
| Control Method | Current Mode PWM |
| 输入电压范围 | 2.97 V to 48 V |
| Output Polarity | Positive |
| Switch Type | External Low-Side N-Channel FET |
| Maximum Switching Frequency | 1 MHz (resistor programmable) |
| Maximum Duty Cycle | 85% |
| 输出数量 | 1 |
| Automotive Qualification | AEC-Q100 Grade 1 |
| 工作温度 | -40C to +125C |
| 封装 | 10-VSSOP / 10-MSOP (3.00mm width) |
| 安装类型 | Surface Mount |
| Packaging | Tape & Reel (TR) |
| Protection Features | Cycle-by-cycle current limit, thermal shutdown |
| RoHS 状态 | Compliant (NOPB / lead-free) |
| Gate Driver Supply | Internal regulated VCC for N-FET drive |
LM3481QMMX/NOPBQ1 引脚配置
| 引脚 1 | SW — Switch node connection to external N-FET drain |
| 引脚 2 | VCC — Internal regulated supply output for gate drive |
| 引脚 3 | GND — Ground reference |
| 引脚 4 | FB — Feedback input from output voltage divider |
| 引脚 5 | COMP — Loop compensation network connection |
| 引脚 6 | FREQ — Switching frequency set resistor |
| 引脚 7 | SS — Soft-start capacitor connection |
| 引脚 8 | VIN — Input supply, 2.97V to 48V |
| 引脚 9 | CS — Current sense input for cycle-by-cycle limit |
| 引脚 10 | AGND — Analog ground for controller reference |
典型应用
LM3481QMMX/NOPBQ1 适用于 6 应用s: Automotive LED Headlamp Driver, Automotive Infotainment Display Boost Rail, On-Board Charger Auxiliary Supply, Industrial 24V Boost Converter, SEPIC Battery-Power Conversion, Gateway and Telematics Power Stage.
Automotive LED Headlamp Driver
The LM3481-Q1 fits automotive LED headlamp boost stages because its 2.97V to 48V VIN absorbs load-dump transients and its AEC-Q100 Grade 1 rating covers the -40C to +125C engine-bay environment. Operating in boost mode with an external low-side N-FET, it steps 12V up to the LED string voltage; cycle-by-cycle current limit plus the current-mode loop enable constant-current LED drive, and 1MHz-capable operation keeps the inductor small for lamp housings.
推荐
Automotive Infotainment Display Boost Rail
Infotainment panels require a stable 12V-to-18V or higher boost rail from the car battery. The LM3481-Q1 drives an external MOSFET, allowing designers to scale output current to the display backlight and logic load without being limited by an internal switch. Its current-mode PWM with 85% duty cycle and resistor-programmable frequency (up to 1MHz) lets the converter sit above the AM band to ease EMI filtering, while AEC-Q100 Grade 1 qualification meets cabin temperature requirements.
推荐
On-Board Charger Auxiliary Supply
EV on-board chargers need an auxiliary rail powered from the high-voltage DC link. The LM3481-Q1's 48V maximum VIN and flyback topology support make it a fit for tapping intermediate 12V/24V/48V buses to generate isolated or non-isolated auxiliary supplies for gate drivers and contactors. Using an external N-FET lets the design handle tens of watts, and thermal shutdown plus cycle-by-cycle current limit provide robust fault handling in high-voltage environments.
推荐
Industrial 24V Boost Converter
Industrial control and instrumentation running from 24V buses frequently need 36V to 48V rails for sensors, OLED displays, or op-amp supplies. The LM3481-Q1 boosts from 24V with ample headroom, and its wide VIN also tolerates 12V fallback operation. The current-mode loop simplifies loop compensation with ceramic output capacitors, and the VSSOP-10 footprint keeps the controller overhead small on dense industrial PCBs.
推荐
SEPIC Battery-Power Conversion
For battery-powered equipment where the input varies above and below the required output, the LM3481-Q1 SEPIC configuration regulates a fixed output from a 3-cell to 4-cell series battery. Its low 2.97V minimum VIN supports deeply discharged cells, while the coupled-inductor SEPIC topology with an external low-side FET delivers efficient step-up/step-down conversion. Programmable frequency up to 1MHz permits small coupled inductors in portable and robotics designs.
推荐
Gateway and Telematics Power Stage
Automotive gateway and telematics modules generate 5V or 8V intermediate rails from a fluctuating 9V to 16V battery input. The LM3481-Q1 in boost mode with pre-boost for cold crank keeps downstream bucks such as the LM5176 or TPS65 family powered during voltage dips. Its small VSSOP-10 package and high switching frequency reduce board area, and AEC-Q100 Grade 1 qualification supports the telematics unit's under-dash temperature profile.
推荐
推荐产品汇总
工程参考数据： LM3481QMMX/NOPBQ1 ——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 | LM3481QMM/NOPB | LM3481MMX/NOPB | MAX668AUB |
|---|---|---|---|---|
| Package | VSSOP-10 (DGS) | VSSOP-10 (DGS) - same | VSSOP-10 (DGS) - same | MSOP-10 - same footprint, different pinout |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Analog Devices |
| Input Voltage Range | 2.97 V to 48 V | 2.97 V to 48 V | 2.97 V to 48 V | 3 V to 28 V |
| Topologies | Boost, SEPIC, Flyback | Boost, SEPIC, Flyback | Boost, SEPIC, Flyback | Boost, SEPIC, Flyback |
| Max Switching Frequency | 1 MHz | 1 MHz | 1 MHz | 500 kHz |
| Automotive Qualification | AEC-Q100 Grade 1 | AEC-Q100 Grade 1 | Not automotive qualified | Not automotive qualified |
| Control Method | Current Mode PWM | Current Mode PWM | Current Mode PWM | Current Mode PWM |
| Pin-to-Pin Drop-In | N/A (reference) | Yes - identical | Yes - identical | No - redesign required |
关键差异点
- AEC-Q100 Grade 1 automotive qualification （对比 LM3481MMX/NOPB)
- Wider 48V VIN than cross-brand MSOP-10 controllers （对比 MAX668AUB)
- Scalable output power via external FET （对比 LM5117QMHX/NOPBQ1)
设计说明
Keep the power loop (input cap, external N-FET, inductor, sense resistor) as tight as possible; the SW node carries high dv/dt and radiates. Route the CS sense line differentially to the sense resistor Kelvin contacts to avoid false current-limit trips from switch-node ringing. Place the FREQ, FB, and COMP components close to their pins with a solid analog ground return to pin 10.
In boost converters the output is connected to VIN through the inductor when the FET fails short, so add reverse protection or a fuse if the load must be protected. Ensure VCC (internal regulator) has the recommended decoupling capacitor or gate drive collapses at high frequency. Never exceed the 48V absolute maximum VIN - automotive load dump requires upstream TVS suppression.
Because this is a controller, thermal design centers on the external MOSFET and sense resistor, not the VSSOP-10 itself. Size the FET for RMS current and switching loss at your frequency; at 1MHz, switching loss dominates, so choose a FET with low Qgd. Verify sense resistor power: P = I^2 x R, and derate at 125C ambient for AEC-Q1 designs.
合规信息
NOPB suffix indicates No Pb (lead-free) per TI ordering nomenclature. AEC-Q100 Grade 1 per TI LM3481-Q1 product page. REACH and halogen-free status not stated in provided data.
