LM5146QRGYRQ1

The LM5146-Q1 100V synchronous buck controller is designed to regulate high input voltage sources or input power rails subject to high-voltage transients, minimizing the need for external surge suppression components. A 40ns high-side switch minimum on-time enables high step-down ratios, supporting direct conversion from a 48V nominal input to low-voltage rails, reducing system complexity and solution cost. The LM5146-Q1 continues to operate at near 100% duty cycle as needed when the input voltage drops to 5.5V, making it well suited for high-performance 48V automotive battery applications, ADAS (surround-view ECU), and HEV/EV systems. Forced PWM (FPWM) mode operation eliminates switching frequency variation to minimize EMI, while a user-selectable diode emulation feature reduces current consumption under light-load conditions. The adjustable switching frequency of up to 1MHz can be synchronized to an external clock source, eliminating beat frequencies in noise-sensitive applications. Cycle-by-cycle overcurrent protection is achieved by sensing the voltage drop across the low-side MOSFET or by using an optional current sense resistor. The LM5146-Q1 voltage-mode controller with line feedforward drives external high-side and low-side N-channel power switches using robust 7.5V gate drivers suitable for standard threshold MOSFETs. The adaptive timing gate driver with 2.3A source and 3.5A sink capability minimizes body diode conduction during switching transitions, reducing switching losses and improving thermal performance when driving MOSFETs at high input voltages and high frequencies. The LM5146-Q1 can be powered from the switching regulator output or another available source to further improve efficiency. A 180° out-of-phase clock output relative to the internal oscillator's synchronization output is ideal for cascaded or multi-phase power supplies, reducing input capacitor ripple current and EMI filter size. Additional features of the LM5146-Q1 include configurable soft-start, open-drain power-good monitor for fault reporting and output monitoring, monotonic start-up into pre-biased loads, integrated VCC bias supply regulator and bootstrap diode, external power tracking, precision enable input with adjustable line UVLO and hysteresis, hiccup-mode overload protection, and thermal shutdown with auto-recovery. The LM5146-Q1 controller is available in a 4.5mm×3.5mm thermally enhanced 20-pin VQFN package with additional clearance for high-voltage pins and wettable flanks to allow optical inspection of solder joint fillets.

Applications

• High-power automotive DC/DC regulators
• Automotive motor drivers, ADAS
• HEV/EV powertrain systems
• Body electronics and lighting
• Infotainment systems and instrument clusters

Key features

• AEC-Q100 qualified for automotive applications: Device Temperature Grade 1: –40°C to +125°C ambient temperature range
• Functional Safety-capable
• Documentation available to aid functional safety system design
• Versatile synchronous buck DC/DC controller
• Wide input voltage range: 5.5V to 100V
• 150°C maximum junction temperature
• 0.8V reference with ±1% feedback accuracy
• Adjustable output voltage range: 0.8V to 60V
• 40ns tON(min) for high VIN/VOUT ratio
• 140ns tOFF(min) for low dropout
• Lossless RDS(on) or shunt current sensing
• Optimized for CISPR 25 Class 5 requirements
• Switching frequency range: 100kHz to 1MHz
• Synchronous input and synchronous output capability
• Selectable diode emulation or FPWM
• 7.5V gate driver for standard VTH MOSFETs
• 14ns adaptive dead-time control
• 2.3A source and 3.5A sink current capability
• Inherent protection features for robust design
• Adjustable output voltage soft-start
• Hiccup mode overcurrent protection
• Input UVLO with hysteresis
• VCC and gate drive UVLO protection
• Precision enable input and open-drain PGOOD indicator for sequencing and control
• Thermal shutdown with hysteresis
• 20-pin VQFN package with wettable flanks
• Create a custom design using the LM5146-Q1 with WEBENCH PowerDesigner