12-95V Input – 5V Output – High Voltage DC-DC Buck Converter

[guclusat]

This is a versatile synchronous buck DC/DC converter built using the LM5008 chip. The operating input voltage range is 12V to 95V DC, providing 5V/120-350mA output. The regulator can provide a load current of up to 350mA, but it’s advisable to draw only 120mA due to the small thermal area on PCB (small PCB). The default output of the converter is set to 5V. Output is adjustable by changing the feedback resistor values R1 and R4. Please refer to the datasheet of the LM5008 chip for more info.

Features​

• Operating Input Voltage Range of 12 V to 95 V
• Output 5V @ 120mA (Output Up to 350mA with fan)
• High Efficiency Operation
• Adaptive Constant On-Time Control Architecture
• Ultra-Fast Transient Response
• No Control Loop Compensation Required
• Nearly Constant Switching Frequency
• PWM On-Time Varies Inversely with Input Voltage
• Low Input Quiescent Current
• Inherent Protection Features for Robust Design
• Intelligent Current Limit Protection
• VCC and Gate Drive UVLO Protection
• Thermal Shutdown Protection with Hysteresis
• PCB Dimensions 20.64 x 14.92MM

The LM5008 350-mA step-down switching converter features all of the functions needed to implement a low-cost and efficient buck regulator. This high-voltage converter has an integrated 100-V N-channel buck switch and operates over an input voltage range of 9 V to 95 V. The device is easy to implement and is provided in the 8-pin VSSOP and the thermally enhanced 8-pin WSON packages. The converter uses a hysteretic control scheme with a PWM on-time inversely proportional to VIN. This feature allows the operating frequency to remain relatively constant. The hysteretic control requires no loop compensation. An intelligent current limit is implemented with forced off-time, which is inversely proportional to VOUT. This scheme ensures short-circuit protection while providing minimum foldback. Other protection features include: thermal shutdown, VCC undervoltage lockout, gate drive undervoltage lockout, and maximum duty cycle limiter.

Connections CN1​

• Pin 1 = DC Input 12V to 95V
• Pin 2 = NC
• Pin 3 = GND
• Pin 4 = NC
• Pin 5 = OP

Schematic​