Analog Devices LTC7890 | Demoboard DC2938A

Description

Demonstration circuit 2938A is a dual output nonisolated synchronous step-down converter that drives all N-channel gallium nitride (GaN) FET power stages. DC2938A 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 dedicated driver feature for GaN FET housed in a small 6mm × 6mm QFN package.The DC2938A operates over an input voltage range from 30V to 72V, while the LTC7890 can operate up to 100V. The DC2938A demo board produces two outputs: 5V and 12V with up to 20A output, respectively. DC2938A is configured with a sense resistor for current sensing. A mode selector allows the DC2938A to operate in forced continuous operation, pulse-skipping or Burst Mode® operation during light loads. DTCA and DTCB selector provides easy adjustment of the dead time to improve efficiency or to tailor the application. DRVSET and DRVUV selector offers option to choose drive voltage from 4V to 5.5V to optimize performance.

Features

• GaN drive technology fully optimized for GaN FETs
• Wide VIN range: 4 V to 100 V
• Wide output voltage range: 0.8 V ≤ VOUT ≤ 60 V
• No catch, clamp, or bootstrap diodes needed
• Internal smart bootstrap switches prevent overcharging of high-side driver supplies
• Internally optimized, smart near zero dead times or resistor adjustable dead times
• Split output gate drivers for adjustable turn on and turn off driver strengths
• Accurate adjustable driver voltage and UVLO
• Low IQ: 5 μA (48 VIN to 5 VOUT, Ch 1 On)
• Programmable frequency (100 kHz to 3 MHz)
• Synchronizable frequency (100 kHz to 3 MHz)
• Spread spectrum frequency modulation
• 40-lead (6 mm × 6 mm), side wettable, QFN package

Typical applications

• Military avionics
• medical systems
• Industrial power systems
• Telecommunications power systems

More information

• Datasheet
• IC product information