Synchronous step-down 2MHz DC/DC controller offers up to 95 percent efficiency
A low 30 ns minimum on-time allows for a high step-down ratio at high operating frequencies. The controlled on-time, valley current-mode architecture and Detect Transient Release feature provide a very fast transient response by increasing operating frequency during a transient event, enabling the output voltage to recover in only a few clock cycles. Up to 12 phases can be paralleled and clocked out of phase for high current applications (up to 250 A).
The LTC3839 operates over a 4.5 V to 38 V input voltage range, encompassing a wide variety of applications including most intermediate bus voltages. Strong onboard N-channel MOSFET gate drivers allow the use of high power external MOSFETs for output currents up to 50 A, at output voltages ranging from 0.6 V to 5.5 V, making the device ideal for point-of-load requirements.
The LTC3839’s differential amplifier provides true remote output voltage sensing of both the positive and negative terminals, enabling high accuracy regulation independent of PCB IR losses (up to ±500 mV). The output current is monitored by sensing the voltage drop across the output inductor (DCR) for highest efficiency or by using a sense resistor for extra precision.
Additional features include an onboard bias voltage LDO, soft-start or tracking, adjustable current limit, overvoltage protection, current limit foldback and external V CC control.
The LTC3839 offers superior total regulation accuracy and is specified to account for all error sources including line, load and differential sensing. The LTC3839 total output voltage accuracy is ±0.25% at 25°C, ±0.67% from 0 to 85ºC, and ±1% maximum DC error over the full -40 to 125°C operating junction temperature range. The LTC3839 is available in a thermally enhanced 5 mm x 5 mm QFN-32 package. The 1,000-piece price starts at $3.18 each.
More information about the LTC3839 DC/DC controller at
www.linear.com/product/LTC3839
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