National Semi Introduces Synchronous Buck Switching Controller for Loads up to 10A

National Semiconductor Corp. introduced a 1 MHz synchronous buck switching controller in an ultra-small MSOP package that is optimized for powering loads up to 10A. The robust LM3743, which requires minimal external circuitry for a smaller overall footprint, also has programmable tracking and extensive protection features which make the controller well-suited for space-constrained designs in communications, high-end consumer, computing and industrial applications.

The LM3743 voltage-mode PWM buck controller operates over the input range of 3 to 5.5V and drives external synchronous MOSFETs at either 300 KHz or 1 MHz, which generates output voltages as low as 0.8V. It features an externally programmable soft start with tracking capability and external compensation. The LM3743 has an externally programmable current limit with low-side MOSFET current sensing that is plus or minus 15% accurate, as well as a hiccup mode of operation, which means that engineers do not need to over-design external components. Additional protection features include under-voltage lockout and a fixed short-circuit, high-side current limit. Reference accuracy is plus or minus 1.75% over the whole operating temperature range of -40 to +125°C.

The LM3743 is offered in a tiny 10-pin mini SOIC package. Available now, the LM3743 is priced at $1.20 each in 1,000-unit quantities.