Synchronous stepdDown DC/DC controller offers up to 95 percent efficiency with 2-MHz operating frequency
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.
Availability and Pricing
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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