LMR33640ADDAR - 4A 36V Synchronous Buck Converter | Texas Instruments
料号： LMR33640ADDAR ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $3.45 | $3.45 |
| 10 | $3.1 | $31.00 |
| 100 | $2.78 | $278.00 |
| 500 | $2.45 | $1,225.00 |
| 1,000 | $2.18 | $2,180.00 |
LMR33640ADDAR 概述
A step-down (buck) DC/DC converter is a switched-mode voltage regulator that steps a higher DC input to a lower DC output by rapidly switching an inductor between input and ground. The LMR33640ADDAR belongs to the synchronous buck family (FETs integrated inside the IC), within the broader hierarchy of switching regulators, then power management ICs, then power management semiconductors. Peak-current-mode control, internal MOSFETs, and wide Vin eliminate the need for an external power stage, making it a fully integrated point-of-load (POL) solution.
Key specifications include 4 A continuous output current, 76 uA quiescent current at no load, 25 uA Iq in light-load mode, 1% feedback reference accuracy, and internal compensation that removes the loop compensation network. The peak-current-mode topology delivers fast transient response and simple Type-II loop compensation, while the 8-pin PowerSOIC package offers a thermal resistance around 50 C/W with thermal pad, suitable for -40 C to +125 C junction operation.
Typical applications include industrial 24 V bus POL rails, factory automation sensor supplies, building automation 12 V/24 V distributed buses, battery-powered test equipment, eMMC/SSD storage power, and aftermarket automotive accessories. Wide Vin tolerance also supports USB-PD and other 5 V to 20 V inrush environments with downstream post-regulation.
When designing with this part, choose inductor and Cout per the datasheet's WEBENCH tool to ensure stability. Place the input ceramic bypass capacitor within 2 mm of the VIN and PGND pins, and route the AGND island as a star point. The PowerSOIC exposed pad MUST be soldered to a copper pour sized to absorb typical 1.5 W to 3 W dissipation.
This page synthesizes distributor pricing, drop-in pin-compatible alternatives, and practical PCB design notes not aggregated in the manufacturer datasheet.
直接替换替代料： LMR33640ADDAR ——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： LMR33640ADDAR （相同外形与封装尺寸） ——差异在于 Package, Switching Frequency, Topology, Control Mode, Input Voltage Range.
快速对比工具——选择替代料号进行并排对比：
LMR33630ADDAR
✅ 直接替换📋 参考替代料（不在目录中）
LMR33620ADDAR
✅ 直接替换📋 参考替代料（不在目录中）
LMR33640CDDAR
✅ 直接替换📋 参考替代料（不在目录中）
TPS54302DDAR
✅ 直接替换📋 参考替代料（不在目录中）
MP4560DN-LF
✅ 直接替换📋 参考替代料（不在目录中）
LMR33640ADDAR 最大额定值与电气特性
| 拓扑 | Synchronous Buck (Step-Down) |
| 输入电压范围 | 3.8 V to 36 V |
| 输出电压范围 | 1 V to 24 V (adjustable) |
| Continuous Output Current | 4 A |
| 开关频率 | 400 kHz (typical) |
| Quiescent Current (no load) | 76 uA (typical) |
| Light-Load Iq | 25 uA (typical) |
| Feedback Reference Accuracy | 1% (over temperature) |
| Control Mode | Peak current mode |
| Enable Input | Precision EN (active high, with PG) |
| Power-Good Flag | Yes (open-drain PG) |
| Internal MOSFETs | Yes (synchronous N-channel high-side and low-side) |
| Internal Compensation | Yes |
| 工作结温 | -40°C to +125°C |
| 封装 | PowerSOIC-8 (DDA) 3.90 mm body |
| MSL 等级 | Level-2 (per JEDEC J-STD-020) |
| Functional Safety | Functional Safety-Capable (documentation available) |
| RoHS 状态 | Compliant |
LMR33640ADDAR 引脚配置
| 引脚 1 | PGND — Power ground return for the internal low-side FET |
| 引脚 2 | VIN — Input supply voltage (3.8 V to 36 V) |
| 引脚 3 | EN — Precision enable input; high = on, low = shutdown |
| 引脚 4 | FB — Feedback node for external resistor divider (AD suffix) |
| 引脚 5 | RT/SS — Frequency / soft-programming pin (resistor to AGND sets fSW) |
| 引脚 6 | PGOOD — Power-good open-drain output (asserts when Vout in regulation) |
| 引脚 7 | AGND — Analog ground; tie to PGND at single point |
| 引脚 8 | SW — Switch node to external inductor (PowerPAD thermal pad on bottom) |
典型应用
LMR33640ADDAR 适用于 6 应用s: Industrial 24 V Distributed Bus POL Rail, Building Automation 12 V / 24 V HVAC Controller, Portable Test and Measurement Equipment, eMMC / SSD Storage Power Rail, Aftermarket Automotive Accessories, Factory Sensor and IO-Link Hub.
Industrial 24 V Distributed Bus POL Rail
The LMR33640ADDAR's 3.8 V to 36 V input range and 4 A continuous current make it ideal as a point-of-load regulator on industrial 24 V factory buses. Place the IC between the bus and a downstream MCU, FPGA, or sensor cluster; the wide Vin tolerance tolerates bus transients and load-dump events common in motor-control and PLC cabinets. The 76 uA quiescent current also keeps standby losses minimal for energy-aware Industry 4.0 sensor nodes.
推荐
Building Automation 12 V / 24 V HVAC Controller
In HVAC thermostats and access-control panels, the LMR33640ADDAR converts a 24 VAC-rectified rail to a stable 3.3 V or 5 V logic rail with 4 A headroom for relays, displays, and radio modules. The peak-current-mode control and internal compensation eliminate external loop components, allowing a compact BOM. The PowerSOIC-8 package is suitable for the high ambient temperatures (60 C to 85 C) found in rooftop HVAC enclosures.
推荐
Portable Test and Measurement Equipment
Handheld oscilloscopes, signal generators, and battery-powered DMMs benefit from the LMR33640ADDAR's wide Vin (3.8 V to 36 V) for charging from USB-PD, 12 V automotive, or 24 V bench supplies. The 4 A capability delivers clean 1.2 V cores for ADCs and DSPs while the 25 uA light-load Iq extends battery runtime. The exposed pad cools the part efficiently in the small enclosures typical of portable instruments.
推荐
eMMC / SSD Storage Power Rail
The LMR33640ADDAR generates the 1.0 V to 3.3 V rails required by eMMC modules, NVMe SSD controllers, and DDR memory in industrial gateways and edge-AI boxes. The 400 kHz switching frequency is above the AM band, easing EMI compliance, while the 1% reference accuracy keeps rail tolerance inside the JEDEC specification for LPDDR4 and PCIe. PGOOD output feeds the storage controller's reset supervisor for sequenced power-up.
推荐
Aftermarket Automotive Accessories
Dashcams, GPS trackers, and 12 V accessory modules use the LMR33640ADDAR as a wide-Vin buck for 5 V or 3.3 V rails from a noisy automotive battery bus. The 36 V rating tolerates jump-start and load-dump surges up to the 38 V absolute maximum. Designers add a TVS such as SMBJ33A on VIN for full ISO 7637-2 transient immunity. The PGOOD output drives a downstream MCU reset for clean boot.
推荐
Factory Sensor and IO-Link Hub
IO-Link masters and IP67 sensor hubs use the LMR33640ADDAR to provide isolated 24 V to 3.3 V conversion with up to 4 A for multiple sensor channels. The internal MOSFETs minimize PCB area in compact DIN-rail housings, while the 1% reference accuracy ensures downstream ADC readings stay calibrated. Wide Vin tolerance handles the long cable drops and inductive kickback from solenoid-driven actuators.
推荐
推荐产品汇总
工程参考数据： LMR33640ADDAR ——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 | LMR33630ADDAR | LMR33620ADDAR | LMR33640CDDAR | TPS54302DDAR | MP4560DN-LF |
|---|---|---|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | MPS |
| Package | PowerSOIC-8 (DDA) | PowerSOIC-8 (DDA) - same | PowerSOIC-8 (DDA) - same | PowerSOIC-8 (DDA) - same | PowerSOIC-8 (DDA) - same | SOIC-8 EP - compatible |
| Output Current | 4 A | 3 A (-25%) | 2 A (-50%) | 4 A (same) | 3 A (-25%) | 2 A (-50%) |
| Input Voltage Range | 3.8 V to 36 V | 3.8 V to 36 V (same) | 3.8 V to 36 V (same) | 3.8 V to 36 V (same) | 4.5 V to 28 V (narrower) | 4.5 V to 36 V (similar) |
| Switching Frequency | 400 kHz | 400 kHz (same) | 400 kHz (same) | 400 kHz (same) | up to 1 MHz (higher) | Programmable to ~2 MHz |
| Output Voltage | Adjustable 1 V to 24 V | Adjustable 1 V to 24 V | Adjustable 1 V to 24 V | Factory fixed (3.3 V or 5 V typical) | Adjustable 0.8 V to 23 V | Adjustable 0.8 V to 30 V |
| Quiescent Current | 76 uA | 76 uA | 76 uA | 76 uA | 120 uA | 20 uA (lower) |
| Power-Good Flag | Yes | Yes | Yes | Yes | No | Yes |
| Functional Safety Capable | Yes | Yes | Yes | Yes | No | No |
关键差异点
- Functional-safety-capable documentation （对比 TPS54302DDAR)
- Wider Vin range (3.8 V to 36 V) （对比 TPS54302DDAR)
- Pin-to-pin scalability with LMR33630 / 620 / 610 （对比 MP4560DN-LF)
设计说明
Place the input ceramic bypass capacitor (4.7 uF X7R or larger) within 2 mm of the VIN and PGND pins to minimize high-frequency switching noise. Keep the SW node trace short and away from FB and RT/SS to avoid noise injection. Tie AGND to PGND at a single point under the IC using a star-ground pattern. The exposed thermal pad must be soldered to a copper pour sized at least 100 mm^2 to keep junction temperature under 125 C at full 4 A load.
Estimated: at VIN=24 V, VOUT=5 V, IOUT=4 A, total dissipation is approximately (24-5)*4 + small quiescent = 76 W? No - buck dissipation is (VIN-VOUT)*IOUT = 19 V * 4 A = 76 W (severe). For practical use at VIN=12 V, VOUT=3.3 V, IOUT=4 A, dissipation is (12-3.3)*4 = 34.8 W still high. Recommended at VIN=12 V, VOUT=5 V, IOUT=3 A, dissipation = 21 W; with 100 mm^2 copper pour (~50 C/W theta_JA), junction rise is ~52 C above 25 C ambient = 77 C, within the 125 C limit. Always de-rate to 3 A in unventilated enclosures.
Do not exceed the absolute-maximum VIN of 38 V or the SW node voltage of 38 V. A TVS diode such as SMBJ33A on VIN is recommended for ISO 7637-2 automotive transient compliance. Do not omit the bootstrap capacitor on the SW-to-BST node - without it the high-side gate will not turn on. The RT/SS pin must have a resistor to AGND; leaving it floating prevents switching. Use X7R (not Y5V) ceramics for CIN and COUT to maintain capacitance at low temperatures.
The 400 kHz fundamental switching frequency places the second harmonic in the AM broadcast band - place a small LC pi-filter on the input if the application is sensitive to conducted EMI in 1.5 MHz to 30 MHz range. The SW node should be surrounded by a ground ring connected to PGND to act as a Faraday shield. For multi-layer boards, place a continuous ground plane directly under the SW node to reduce radiated emissions below CISPR 22 limits.
合规信息
RoHS and REACH compliant per TI product page. Functional-safety-capable documentation available but not AEC-Q100 qualified. Use LMR33640-Q1 suffix parts for automotive AEC-Q100 requirements.
