LM25149

• Two integrated EMI mitigation mechanisms
  • Active EMI filter for enhanced EMI performance at lower frequencies
  • Dual random spread spectrum (DRSS) for enhanced EMI performance across low and high-frequency bands
  • EMI reduced by an average of 25 dBµV
  • Reduces the external differential-mode filter size by 50% and lowers systems cost
• Versatile synchronous buck DC/DC controller
  • Wide input voltage range of 3.5 V to 42 V
  • 1% accurate, fixed 3.3-V, 5-V, 12-V, or adjustable outputs from 0.8 V to 36 V
  • 150°C maximum junction temperature
  • Shutdown mode current: 2.2 µA
  • No-load standby current: 9 µA
• Switching frequency from 100 kHz to 2.2 MHz
  • SYNC in and SYNC out capability
• Inherent protection features for robust design
  • Internal hiccup-mode overcurrent protection
  • ENABLE and PGOOD functions
  • VCC, VDDA, and gate-drive UVLO protection
  • Internal or external loop compensation
  • Thermal shutdown protection with hysteresis
• Create a custom design using the LM25149 with WEBENCH Power Designer

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The LM25149 is a 42-V synchronous buck DC/DC controller for high-current single-output applications. Refer to the Errata. The device uses 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 mode (paralleled output) with accurate current sharing for high-current applications. The LM25149 can operate at input voltages 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). 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 noise or ripple voltage. DRSS combines a low-frequency triangular and high-frequency random modulation to optimize EMI preformance in the low-frequency and high-frequency radio frequency bands.

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, internal 2.8-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 wettable flank pins to facilitate optical inspection during manufacturing.