LM5146-Q1

• AEC-Q100 Qualified for Automotive Applications:
  • Device Temperature Grade 1: –40°C to +125°C Ambient Temperature Range
• Versatile Synchronous Buck DC/DC Controller
  • Wide Input Voltage Range of 5.5 V to 100 V
  • Adjustable Output Voltage From 0.8 V to 60 V
  • Voltage-mode Control With Line Feedforward
• Meets CISPR 25 EMI Standard
• Lossless R_DS(on) or Shunt Current Sensing
• Switching Frequency From 100 kHz to 1 MHz
  • SYNC In and SYNC Out Capability
• 40-ns Minimum On-Time for High V_IN / V_OUT Ratio
• 140-ns Minimum Off-Time for Low Dropout
• 0.8-V Reference With ±1% Feedback Accuracy
• 7.5-V Gate Drivers for Standard V_TH MOSFETs
  • 14-ns Adaptive Dead-Time Control
  • 2.3-A Source and 3.5-A Sink Capability
  • Low-Side Soft Start for Prebiased Start-Up
• Adjustable Soft Start or Optional Voltage Tracking
• Precision Enable Input and Open-Drain Power-Good Indicator for Sequencing and Control
• Inherent Protection Features for Robust Design
  • Hiccup-Mode Overcurrent Protection
  • Input UVLO With Hysteresis
  • VCC and Gate-Drive UVLO Protection
  • Thermal Shutdown Protection With Hysteresis
• 20-Pin VQFN Package With Wettable Flanks
• Create a Custom Design Using the LM5146-Q1 With WEBENCH^® Power Designer

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The LM5146-Q1 100-V synchronous buck controller regulates from a high input voltage source or from an input rail subject to high voltage transients, minimizing the need for external surge suppression components. A high-side switch minimum on-time of 40 ns gives large step-down ratios, enabling the direct step-down conversion from a 48-V nominal input to low-voltage rails for reduced system complexity and solution cost. The LM5146-Q1 continues to operate during input voltage dips as low as 5.5 V, at nearly 100% duty cycle if needed, making it an excellent choice for high-performance 48-V battery automotive applications, ADAS (surround view ECU) and HEV/EV systems.

Forced-PWM (FPWM) operation eliminates switching frequency variation to minimize EMI, while user-selectable diode emulation lowers current consumption at light-load conditions. Measuring the voltage drop across the low-side MOSFET or with an optional current sense resistor gives cycle-by-cycle overcurrent protection. The adjustable switching frequency as high as 1 MHz can be synchronized to an external clock source to eliminate beat frequencies in noise-sensitive applications.

The LM5146-Q1 voltage-mode controller with line feedforward drives external high-side and low-side N-channel power switches with robust 7.5-V gate drivers suitable for standard-threshold MOSFETs. Adaptively-timed gate drivers with 2.3-A source and 3.5-A sink capability minimize body diode conduction during switching transitions, reducing switching losses and improving thermal performance when driving MOSFETs at high input voltage and high frequency. The LM5146-Q1 can be powered from the output of the switching regulator or another available source, further improving efficiency.

A 180° out-of-phase clock output relative to the internal oscillator at SYNCOUT works well for cascaded or multi-channel power supplies to reduce input capacitor ripple current and EMI filter size. Additional features of the LM5146-Q1 include a configurable soft start, an open-drain power-good monitor for fault reporting and output monitoring, monotonic start-up into prebiased loads, integrated VCC bias supply regulator and bootstrap diode, external power supply tracking, precision enable input with hysteresis for adjustable line undervoltage lockout (UVLO), hiccup-mode overload protection, and thermal shutdown protection with automatic recovery.

The LM5146-Q1 controller is offered in a 4.5-mm × 3.5-mm thermally enhanced, 20-pin VQFN package with additional spacing for high-voltage pins and wettable flanks for optical inspection of solder joint fillets.