Analog Devices LTC7815 | Demoboard DC2738A

Description

Demonstration circuit 2738A is a triple output synchronous step-up/dual step-down supply featuring the LTC®7815. The demonstration circuit is designed for twobuck 5V/8A, 3.3V/8A outputs supplied by a boost 10V/7A output. Benefiting from this feature, the buck outputs are able to maintain regulation over a wide input voltage range of 4.5V to 36V which is suitable for automotive or other battery fed applications. Also, the demonstration circuituses a drop-in layout that the main buck circuit components fit in an area of three-quarter inches by 1.5 inches,while the main boost circuit area is three-quarter inchesby 1.75 inches. The package style for the LTC7815 is a 38-pin exposed pad QFN.The main features of the board include rail tracking (buck channels only), an internal 5V linear regulator for bias,separated RUN pins for each output, a PGOOD signal (CH1only), an over voltage indicator for CH3 and a mode selector that allow the converter to run in CCM, pulse-skipping or Burst Mode® operation. Synchronization to an externalclock is also possible. The LT7815 data sheet gives a complete description of these parts, operation and application information. The data sheet must be read in conjunctionwith this quick start guide for demo circuit 2738A.

Features

• Dual Buck Plus Single Boost Synchronous Controllers
• Wide Bias Input Voltage Range: 4.5V to 38V
• Outputs Remain in Regulation Through Cold Crank Down to a 2.5V Input Supply Voltage
• Buck Output Voltage Range: 0.8V ≤ VOUT ≤ 24V
• Boost Output Voltage Up to 60V
• Low Operating IQ: 28μA (One Channel On)
• RSENSE or DCR Current Sensing
• 100% Duty Cycle for Boost Synchronous MOSFET Even in Burst Mode® Operation
• Phase-Lockable Frequency (320kHz to 2.25MHz)
• Programmable Fixed Frequency (320kHz to 2.25MHz)
• Very Low Buck Dropout Operation: 98% Duty Cycle
• Small 38-Lead 5mm × 7mm QFN Package

Typical applications

• Automotive Always-On and Start-Stop Systems
• Multioutput Buck-Boost Applications
• Distributed DC Power Systems
• Battery Operated Digital Devices

More information

• Datasheet
• IC product information