The LM25149 is a 42-V, ultra-low IQ synchronous buck DC/DC controller for high-current, single-output applications. The controller uses a peak current-mode control architecture for easy loop compensation, fast transient response, and excellent load and line regulation. The LM25149 can be set up in interleaved dual-phase mode with accurate current sharing for high-current applications. It can operate with VIN as low as 3.5 V, at nearly 100% duty cycle if needed.
The LM25149 has two unique EMI reduction features: active EMI filter and dual random spread spectrum (DRSS). The active EMI filter senses any noise or ripple voltage on the DC input bus and injects an out-of-phase cancellation signal to reduce the disturbance. DRSS combines low-frequency triangular and high-frequency randomized modulations to mitigate EMI across lower and higher frequency bands, respectively. This hybrid technique aligns with the multiple resolution bandwidth (RBW) settings specified in industry-standard EMC tests.
Additional features of the LM25149 include 150°C maximum junction temperature operation, user-selectable diode emulation for lower current consumption at light-load conditions, open-drain power-good flag for fault reporting and output monitoring, precision enable input, monotonic start-up into prebiased load, integrated VCC bias supply regulator and bootstrap diode, internal 3-ms soft-start time, and thermal shutdown protection with automatic recovery.
The LM25149 controller comes in a 3.5-mm × 5.5-mm thermally enhanced, 24-pin VQFN package with an exposed pad to aid in thermal dissapation.
| Type | Title | Date | ||
|---|---|---|---|---|
| * | Data sheet | LM25149 42-V Synchronous Buck DC/DC Controller with Ultra-Low IQ and Integrated Active EMI Filter datasheet (Rev. B) | PDF | HTML | 15 Dec 2021 |
| White paper | Time-Saving and Cost-Effective Innovations for EMI Reduction (Rev. A) | PDF | HTML | 28 Nov 2023 | |
| Application note | How to Implement a Simple Constant Current Regulation Scheme to a PCM Based Buck | PDF | HTML | 16 Aug 2023 | |
| User guide | LM25149-Q1 EVM User's Guide (Rev. A) | PDF | HTML | 29 Apr 2022 | |
| Functional safety information | LM25149 Functional Safety, FIT Rate, Failure Mode Distribution and Pin FMA | PDF | HTML | 07 Dec 2021 | |
| E-book | An Engineer’s Guide to Low EMI in DC/DC Regulators | 21 Apr 2021 | ||
| Technical article | How to reduce EMI and shrink power-supply size with an integrated active EMI filte | PDF | HTML | 05 Apr 2021 |
For additional terms or required resources, click any title below to view the detail page where available.
The LM5149-Q1EVM-400 high-density evaluation module (EVM) is designed to showcase the performance of the LM5149-Q1 high-performance, automotive, synchronous buck DC/DC buck controller. The EVM operates over a wide input voltage range of 15 V to 72 V to deliver a fixed 12-V output with better than (...)
| Package | Pins | CAD symbols, footprints & 3D models |
|---|---|---|
| VQFN (RGY) | 24 | Ultra Librarian |
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