Analog Devices LT8641A | Demoboard EVAL-LT8641A-AZ

Description

Evaluation circuit EVAL-LT8641A-AZ is a 65V, 3.5A/5A peak synchronous step-down Silent Switcher® with spread spectrum frequency modulation featuring the LT8641A. The demo board is designed for 5V output from a 5.5V to 65V input. The wide input range allows a variety of input sources, such as automotive batteries and industrial supplies. The LT8641A is a compact, ultralow emission, high efficiency, high speed synchronous monolithic step-down switching regulator. Top and bottom power switches, compensation components, and other necessary circuits inside the LT8641A minimize external components and simplify design. The special Silent Switcher architecture minimizes EMI emissions. The selectable spread spectrum mode can further improve EMI performance. Ultralow 2.5μA quiescent current in Burst Mode® operation achieves high efficiency at very light loads. Fast minimum on-time of 35ns enables high VIN to low VOUT conversion at high frequency.The LT8641A switching frequency can be programmed either through oscillator resistor or external clock over a 200kHz to 3MHz range. The default frequency of the evaluation board is 2MHz. The SYNC pin on the evaluation board is grounded by JP1 for low ripple burst mode operation. Move JP1 to PULSE SKIPPING position to change the operation mode to pulse-skipping operation. Once JP1 is on SPREAD SPECTRUM position, VCC is applied to the SYNC pin for low EMI spread spectrum operation. To synchronize to an external clock, move JP1 to SYNC and apply the external clock to the SYNC turret. Figure 1 in the user guide shows the efficiency of the circuit at 12V and 24V input in Burst Mode operation.

Features

• Silent Switcher® Architecture
• Ultralow EMI Emissions
• Spread Spectrum Frequency Modulation
• High Efficiency at High Frequency
• Up to 95% Efficiency at 1MHz, 12VIN to 5VOUT
• Up to 94% Efficiency at 2MHz, 12VIN to 5VOUT
• Wide Input Voltage Range: 3V to 65V
• 3.5A Maximum Continuous, 5A Peak Transient Output
• Ultralow Quiescent Current Burst Mode® Operation
• 2.5μA IQ Regulating 12VIN to 3.3VOUT
• Output Ripple < 10mVP-P
• Fast Minimum Switch On-Time: 35ns
• True 2MHz Operation for 24VIN Systems
• Low Dropout Under All Conditions: 130mV at 1A
• Safely Tolerates Inductor Saturation in Overload
• Adjustable and Synchronizable: 200kHz to 3MHz
• Output Soft-Start and Tracking
• Small 18-Lead 3mm × 4mm Side Wettable QFN with Improved Solder Joint Reliability
• AEC-Q100 Qualified for Automotive Applications

Typical applications

• Automotive
• Industrial Supplies, General Purpose Step-Down

More information

• Datasheet
• IC product information