The evaluation circuit EVAL-LTC7897-AZ features the LTC®7897: a 140V Low IQ Synchronous Buck Controller with Programmable 5V to 10V Gate Drive. Split gate drivers allow for easily adjustable turn-on and turn-off of FETs. User adjustable adaptive and smart dead time control modes are available for optimal gate timing. Additionally, the IC features low IQ, up to 2.5MHz programmable/synchronizable switching frequency, spread spectrum, and a small 28-lead (4mm x 5mm) QFN package. These features allow for a wide variety of applications including industrial, military, medical, and telecommunications systems.
The EVAL-LTC7897-AZ operates from a 16V to 100V input voltage range and generates a 12V, 20A output (see Figure 8 in user guide). The LTC7897 has a precision voltage reference providing an output voltage with 2% tolerance over the full operating conditions. The EVAL-LTC7897-AZ is set to a 200kHz switching frequency, which results in a small and efficient circuit. The converter achieves over 93% efficiency with a 20A load at full operating VIN and peak efficiency over 96%.
The LTC7897 supports output voltages from 0.8V to 135V. The evaluation circuit has been designed with 150V FETs. Various FETs of similar footprint can be substituted to fit a wide array of applications.
The EVAL-LTC7897-AZ provides a high-performance, cost-effective solution for generating a 12V output. The LTC7897 data sheet gives a complete description of this part, its operation, and application information. The data sheet must be read in conjunction with this user guide for EVAL-LTC7897-AZ.
Design files for this circuit board are available at www.analog.com.
