Analog Devices LT8608 | Demoboard DC2521A-A

Description

Demonstration circuit 2521A is a 42V, 1.5A micropowersynchronous step-down regulator featuring the LT8608/LT8608B. There are two assembly versions. DC2521A-Ais for the LT8608 and DC2521A-B is for the LT8608B.The LT8608/LT8608B is a compact, high efficiency, highspeed synchronous monolithic step-down switchingregulator. Top and bottom power switches, compensationcomponents and other necessary circuits are insideof the 2mm × 2mm DFN package to minimize externalcomponents and simplify design. The difference LT8608and LT8608B is the LT8608 works under low rippleBurst Mode® operation at light load condition, while theLT8608B has pulse-skipping mode for light load. Dueto the Burst Mode operation, LT8608 consumes only1.7μA of quiescent current when output is regulated at5V. LT8608B has higher quiescent current because of itspulse-skipping mode operation.The demo board is designed for 5V output from a 5.5Vto 42V input. The wide input range allows a variety ofinput sources, such as automotive batteries and industrialsupplies.The demo board has an EMI filter installed. The radiatedEMI performances of the board (with EMI filter) are shownin Figure 2 and Figure 3. The red lines in Figure 2 andFigure 3 are CISPR 25 Class 5 peak limit. To use the EMIfilter, the input should be tied to VEMI, not VIN. An inductorL2, which is a 0Ω jumper on the board by defaultnow, can be added in the EMI filter to further reduce theconducted emission.The LT8608 data sheet gives a complete description ofthe part, operation and application information. The datasheet must be read in conjunction with this demo manualfor DC2521A.

Features

• Wide Input Voltage Range: 3.0V to 42V
• Ultralow Quiescent Current Burst Mode® Operation:
• <2.5μA IQ Regulating 12VIN to 3.3VOUT
• Output Ripple <10mVP-P
• High Efficiency 2MHz Synchronous Operation:

• 92% Efficiency at 0.5A, 5VOUT from 12VIN

• 1.5A Continuous Output Current
• Fast Minimum Switch-On Time: 35ns
• Adjustable and Synchronizable: 200kHz to 2.2MHz
• Spread Spectrum Frequency Modulation for Low EMI
• Allows Use of Small Inductors
• Low Dropout
• Peak Current Mode Operation
• Accurate 1V Enable Pin Threshold
• Internal Compensation
• Output Soft-Start and Tracking
• Small 10-Lead MSOP Package or 8-Lead 2mm × 2mm DFN Package

Typical applications

• General Purpose Step Down / Low EMI Step Down

More information

• Datasheet
• IC product information