Micrel's HV synchronous buck regulator family uses FETZilla tech to stay cool in tiny package



The MIC28511/12/13 family of buck converters

Micrel, an industry leader in high-performance linear and power solutions as well as LAN and timing and communications solutions, introduced the MIC28511/12/13, a family of pin-compatible high voltage (HV) synchronous step-down switching regulators with integrated power switches capable of providing up to 4A (MIC28513) output current and a wide input supply range from 4.6V to 70V (MIC28512). The MIC28511/12/13 are offered in both Hyper Speed Control and HyperLight Load architectures, which allow for high VIN (low VOUT) operation and ultra-fast transient response while reducing the required output capacitance and providing very good light-load efficiency. These products can be used in wide variety applications including industrial control, power metering, telecom, and medical equipment.


"Small and reliable solutions are mandatory for products that must perform under harsh environments and have space constraints such as industrial applications where the systems are subject to high voltage spikes or high operating ambient temperatures. The MIC28511/12/13 family of buck converters was designed to provide the high voltage capabilities to withstand these voltage spikes in a tiny 3mm x 4mm package, without compromising efficiency and thermal performance," noted Brain Hedayati, vice president of marketing for linear and power solutions at Micrel. "Integrating Micrel's HV buck controller, which has a wide input voltage range, with Micrel's new FETZillaTM power MOSFETs and advanced packaging technology, enables Micrel to offer one of the highest power density solutions in the industry. This solution saves customers board space, heat sink cost, and cooling energy."


The MIC28511/12/13 features adjustable output voltage as low as 0.8V with a guaranteed accuracy of ±1 percent. A constant switching frequency can be programmed from 200kHz to 680kHz thereby allowing the customer increased flexibility in using a small inductor or operating at higher efficiency using lower switching frequency. The MIC28511/12/13 offers a full suite of protection features for reliable solutions under fault conditions, including under-voltage lockout to ensure proper operation under power sag conditions, internal soft start to reduce inrush current, fold-back current limit, "hiccup" mode short-circuit protection, and thermal shutdown. The MIC28511/12/13 devices operate at -40-degC to +125-degC junction temperature range and are offered in very small 24-pin 3mm x 4mm FCQFN packages. The MIC28511/12/13 are currently available in volume quantities with 1,000 quantity pricing starting at $1.49/$1.85/$1.42 respectively.