Evaluation Board For the IR3891 DC-DC Voltage Regulator

The IR3891 is a dual synchronous buck converter, providing a compact, high performance and flexible solution in a small 5mm X 6mm Power QFN package. Key features offered by the IR3891 include internal Digital Soft Start, precision 0.5V reference voltage, Power Good, thermal protection, programmable switching frequency, Enable input, input under-voltage lockout for proper start-up, enhanced line/ load regulation with feed forward, external frequency synchronization with smooth clocking, internal LDO, pre-bias start-up, output over voltage protection as well as open feedback line protection. Output over-current protection function is implemented by sensing the voltage developed across the on-resistance of the synchronous rectifier MOSFET for optimum cost and performance and the current limit is thermally compensated.

• Dual Output in 5x6mm PQFN
• Out of phase operation to reduce Input Capacitors
• Programmable Switching Frequency up to 1.5MHz
• Vin = +12.0V
• Fs = 600kHz
• Vout1 = +1.8V @ 4A Vout2 = +1.2V @ 4A
• L1 = 2.2uH L2 = 1.5uH
• Cout1=4x22uF (ceramic 0805) Cout2=4x22uF (ceramic 0805)
• Cin= 4x10uF (ceramic 1206) + 1x330uF (electrolytic)