Evaluation circuit EVAL-LTC7890-BZ is a dual output synchronous step-down converter that drives N-channel silicon (Si) field effect transistors (FETs). The EVAL-LTC7890-BZ evaluation board features 100V logic-level Si FETs.
EVAL-LTC7890-BZ features the LTC®7890: a low quiescent current, high frequency (programmable fixed frequency from 100kHz up to 3MHz), dual step-down DC/DC synchronous controller, with a dedicated driver feature for GaN FETs, which can also be used to drive logic-level silicon FETs. To evaluate the LTC7890 with GaN FETs, refer to the EVAL-LTC7890-AZ evaluation board, which does 12VOUT at 20A and 5VOUT at 20A.
The EVAL-LTC7890-BZ operates over an input voltage range from 16V to 72V, while the LTC7890 can operate up to 100V. The EVAL-LTC7890-BZ evaluation circuit produces two outputs: 5V and 12V, with up to 10A on each output. EVAL-LTC7890-BZ is configured with sense resistors for current sensing. A mode selector allows the EVAL-LTC7890-BZ to operate in forced continuous operation, pulse-skipping or Burst Mode® operation during light loads. The EXTVCC pin permits the LTC7890 to be powered from the output of the switching regulator or other available source, reducing power dissipation, and improving efficiency. Refer to the LTC7890 data sheet for a complete description of the part operation and application information.
The performance summary table summarizes the performance of the evaluation circuit at room temperature. The evaluation circuit can be easily modified for different applications, including 2-phase single output. The LTC7890 is housed in a 40-lead (6mm × 6mm), side wettable, QFN package. Refer to the data sheet in conjunction with this EVAL-LTC7890-BZ evaluation circuit user guide.
Design files for this circuit board are available at www.analog.com.
