TI LM25145RGYR

The LM25145 42V synchronous buck controller is designed to regulate the voltage of high input voltage sources or input power rails subject to high-voltage transients, thereby minimizing the need for external surge suppression components. The 40ns minimum on-time of the high-side switch facilitates a large step-down ratio, supporting direct step-down conversion from a 24V nominal input to a low-voltage rail, thus reducing system complexity and solution cost. The LM25145 can continue to operate at a duty cycle close to 100% as needed when the input voltage suddenly drops to 6V, making it ideal for high-performance industrial control, robotics, data communication, and RF power amplifier applications. Forced PWM (FPWM) mode operation eliminates frequency variations to minimize EMI, while the user-selectable diode emulation function reduces current consumption under light load conditions. Cycle-by-cycle overcurrent protection can be achieved by measuring the voltage drop across the low-side MOSFET or using an optional current sense resistor. An adjustable switching frequency of up to 1MHz can be synchronized to an external clock source to eliminate beat frequencies in noise-sensitive applications. The LM25145 voltage mode controller drives external high-side and low-side N-channel power switches using a reliable 7.5V gate driver suitable for standard threshold MOSFETs. An adaptive timing gate driver with 2.3A source and 3.5A sink capabilities minimizes body diode conduction during switching transitions, reducing switching losses when driving MOSFETs at high input voltages and high frequencies and improving thermal performance. The LM25145 can be powered from the output of the switching regulator or other available sources, further improving efficiency. A 180° out-of-phase clock output (synchronous output relative to the internal oscillator) is ideal for cascaded or multi-channel power supplies, reducing input capacitor ripple current and EMI filter size. Other features of the LM25145 include configurable soft start, open-drain power good monitoring for fault reporting and output monitoring, monotonic start-up into pre-biased loads, an integrated VCC bias supply regulator and bootstrap diode, external power supply tracking, a precision enable input with hysteresis for adjustable line under-voltage lockout (UVLO), discontinuous mode overload protection, and thermal shutdown protection with automatic recovery. The LM25145 controller is available in a thermally enhanced 20-pin VQFN package measuring 3.5mm×4.5mm, with additional spacing provided for high-voltage pins and wettable flanks to enable optical inspection of solder joint fillets.

• Versatile synchronous buck DC/DC controller
• Wide input voltage range: 6V to 42V
• Adjustable output voltage range: 0.8V to 40V
• Compliant with EN55022/CISPR 22 EMI standards
• Lossless RDS(on) or shunt current sensing
• Switching frequency range: 100kHz to 1MHz
• Synchronous input and synchronous output capability
• 40ns minimum on-time for high VIN/VOUT ratio
• 140ns minimum off-time for low dropout
• 0.8V reference with ±1% feedback accuracy
• 7.5V gate driver for standard VTH MOSFETs
• 14ns adaptive dead-time control
• 2.3A source and 3.5A sink current capability
• Low-side soft-start for pre-biased startup
• Adjustable soft-start or optional voltage tracking
• Fast line and load transient response
• Voltage mode control with line feedforward
• High gain-bandwidth error amplifier
• 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 with hysteresis
• VQFN-20 package with wettable flanks
• Create custom designs with LM25145 using WEBENCH Power Designer

• Telecom infrastructure
• Factory automation
• Test & measurement
• Industrial motor drives