DC-DC buck converter with inbuilt red LED voltmeter

This great little step-down (buck) DC-DC converter has an inbuilt red LED 3 digit voltmeter which can display either the input voltage or the output voltage, depending on the position of the pushbutton switch. There're two small LEDs on the board that light when you are viewing each voltage, so there's never any confusion.

Another pushbutton allows you to turn the display off altogether to reduce power consumption and it remembers which voltage was being measured when turned back on.

Specifications:

• Input voltage range: 4-40V (40V the absolute maximum voltage)
• Output voltage range: 1.25-37V (input must be >2V above output voltage)
• Output current: 2A continuous, 3A max
• Output power: 15W max
• Switching frequency: 150kHz
• Ripple peak: 100mV
• Quiescent current: 20mA
• Size: 56mm x 36mm x 14mm high, mounting hole spacing is around 50mm x 28mm
• Voltmeter precision: ±5% or ±0.05V
• Thermal shutdown and current limit protection