Demonstration Circuit 2841A is a 42V, 15A synchronous step-down Silent Switcher 2 with spread spectrum frequency modulation featuring the LT8648S. The demo board is designed for 5V output from a 5.7V to 42V input. The wide input range allows a variety of input sources, such as automotive batteries and industrial supplies. The LT8648S is a compact, ultralow emission, high efficiency, and high speed synchronous monolithic stepdown switching regulator. The integrated bypass capacitors optimize the fast current loops and make it easier to minimize EMI emissions by reducing layout sensitivity. Selectable spread spectrum mode further improves EMI performance, making it perfect solution to the noise sensitive applications.  Peak current mode control with minimum on-time of as small as 25ns allows high step-down conversion even at high frequency. The LT8648S switching frequency can be programmed either via oscillator resistor or external clock over a 200kHz to 2.2MHz range. The default frequency of demo circuit 2841A is 400kHz. The SYNC/MODE pin on the demo board DC2841A is grounded (JP1 at BURST position) by default for low ripple Burst Mode® operation. It can be configured into different operation modes through JP1 and SYNC terminal (Table 1). Figure 1 shows the efficiency of the circuit at 12V input and 24V input in force continuous mode without spread spectrum. To get accurate efficiency measurement, measure the input voltage at the VIN SENSE terminal and measure the output voltage at the VO SENSE terminal.  Figure  2 shows the LT8648S temperature rising on DC2841A demo board under different load conditions. The LT8648S is assembled in a 7mm × 4mm LQFN package with exposed pads for low thermal resistance. The rated maximum load current is 15A, while derating is necessary for certain input voltage and thermal conditions. The demo board has an EMI filter installed. The EMI performance of the board is shown on Figure 3. The red line in Radiated EMI Performance is CISPR25 Class 5 peak limit. The figure shows that the circuit passes the test with a wide margin. To achieve EMI performance as shown in Figure 3, the input EMI filter is required and the input voltage should be applied at VIN_EMI terminal, and the test setup can be referred to the CISPR25 standards. If the input is applied to VIN terminal, the EMI filter is bypassed.  The LT8648S data sheet gives a complete description of the part, operation and application information. The data sheet must be read in conjunction with this demo manual for DC2841A. The layout recommendations for low EMI operation and maximum thermal performance are available in the data sheet section Low EMI PCB Layout and Thermal Considerations and Peak Output Current. Contact ADI applications engineer for support.

Demonstration Circuit 2745A features the LTC3309A 5V, 6A synchronous step-down silent switcher operating as a 2MHz 3.3V to 1.2V 6A buck regulator. The LTC3309A supports adjustable output voltages from 0.5V to VIN, operating frequencies from 1MHz up to 3MHz. The LTC3309A is a compact, ultralow emission, high efficiency, and high speed synchronous monolithic step-down switching regulator. Fast minimum on-time of 22ns enables high VIN to low VOUT conversion at high frequency. DC2745A operating mode may be selected as Burst Mode® operation, skip or forced continuous (FC) mode. Setting JP1 to the FC/SYNC position will allow the LTC3309A to sync to a clock frequency from 1MHz to 3MHz. The LTC3309A operates in forced continuous mode when syncing to an external clock. RT is connected to VIN through a 0Ω resistor, R9, which sets the operating frequency to 2MHz. The frequency can be easily changed by removing R9 and setting an appropriate resistor in the R4 location to obtain the desired frequency. Refer to the LTC3309A data sheet for the proper RT value. The DC2745A also has an EMI filter to reduce conducted EMI. This EMI filter can be included by applying the input voltage at the VIN EMI terminal. The EMI performance of the board is shown in the EMI Test Results section. The red lines in the EMI performance graphs illustrate the CISPR25 Class 5 peak limits for the conducted and radiated emission tests. The LTC3309A data sheet gives a complete description of the part, operation and application information. The data sheet must be read in conjunction with this demo. The LTC3309A is assembled in a 3mm × 3mm LQFN package with exposed pads for low thermal  resistance. The layout recommendations for low EMI operation and maximum thermal performance are available in the data sheet section Low EMI PCB Layout. The Efficiency vs Load graph shows the efficiency and the power loss of the circuit with a 3.3V input in Burst Mode operation. The LTC3309A is available in a 12-lead 2mm × 2mm LGA package.

to 300mA) battery-powered applications. The peak switch current is user-programmable with an

DC187A-B: Demo Board for the LT1374 4.5A, 500kHz Step-Down Switching Regulator.

DC187A-A: Demo Board for the LT1374 4.5A, 500kHz Step-Down Switching Regulator.

Demonstration circuit 2991A features the LTC3308A 5V, 4A synchronous step-down Silent Switcher® operating as a 2.0MHz, 3.3V to 1.2V 4A buck regulator. The LTC3308A supports adjustable output voltages from 0.5V to VIN with operating frequencies from 1MHz up to 3MHz. The LTC3308A is a compact, ultralow emission, high efficiency, and high speed synchronous monolithic stepdown switching regulator. A minimum on-time switching of 22ns enables high VIN to low VOUT conversion ratios at high frequencies. The DC2991A operating mode may be selected as BURST, SKIP or Forced Continuous (FC) mode. Setting JP1 to the FC/SYNC position will allow the LTC3308A to sync to a clock frequency from 1MHz to 3MHz. The LTC3308A operates in forced continuous mode when syncing to an external clock. The DC2991A is set to a fixed 2MHz frequency by connecting RT to VIN through a 0Ω resistor, R9. The frequency can be easily changed by removing R9 and setting an appropriate resistor in the R4 location to obtain the desired frequency. Refer to the LTC3308A data sheet for the proper RT value for a desired switching frequency. The DC2991A also has an EMI filter to reduce conducted EMI. This EMI filter can be included by applying the input voltage at the VIN EMI terminal. The EMI performance of the board is shown in the EMI Test Results section. The red lines in the EMI performance graphs illustrate the CISPR25 Class 5 peak limits for the conducted and radiated emission tests. The LTC3308A data sheet gives a complete description of the device, operation and application information. The data sheet must be read in conjunction with this demo manual. The LTC3308A is assembled in a 2mm × 2mm LQFN package with exposed pads for low thermal resistance. The layout recommendations for low EMI operation and maximum thermal performance are available in the data sheet section: Low EMI PCB Layout.  The Efficiency vs Load graph shows the efficiency and the power loss of the circuit with a 3.3V input in Burst Mode operation.

DC1273A: Demo Board for LT1938 - 25V, 2.2A, 2.8MHz Step-Down Switching Regulator

DC1316A: Demo Board for LT1913 25V, 3.5A, 2.4MHz Step-Down Switching Regulator.

DC697A: Demo Board for the LT1943 High Current Quad Output Regulator for TFT LCD Panels.

DC204A-B: Demo Board for the LT1776 Wide Input Range, High Efficiency, Step-Down Switching Regulator.