TI LM5145RGYT

The LM5145 75V 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. The 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 LM5145 continues to operate at nearly 100% duty cycle as needed when the input voltage drops to 6V, making it an ideal choice for high-performance industrial control, robotics, data communications, and RF power applications. Forced PWM (FPWM) mode operation eliminates switching frequency variation for maximum EMI reduction, while the user-selectable diode emulation function reduces current consumption under light-load conditions. The adjustable switching frequency of up to 1MHz can be synchronized to an external clock source to eliminate beat frequencies in noise-sensitive applications. Measuring the voltage drop across the low-side MOSFET or with an optional current sense resistor gives cycle-by-cycle overcurrent protection. The LM5145 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 LM5145 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 multichannel power supplies to reduce input capacitor ripple current and EMI filter size. Additional features of the LM5145 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 LM5145 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.

• Versatile synchronous step-down DC/DC controller
• Wide input voltage range: 6V to 75V
• 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
• Optimized for CISPR 32 requirements
• Switching frequency range: 100kHz to 1MHz
• Synchronous input and synchronous output functionality
• 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 capability
• Low-side soft-start for pre-biased startup
• Fast line and load transient response
• Voltage mode control with line feed-forward
• High gain-bandwidth error amplifier
• Inherent protection features for robust design
• Adjustable output voltage soft-start
• Discontinuous 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
• Use LM5145 with WEBENCH Power Designer to create custom designs

• Remote Radio Unit (RRU) and BTS
• Networking and computing
• Non-isolated PoE and IP cameras
• Industrial motor drives