Demonstration circuit 2779A is an 8V, 16A synchronous step-down Silent Switcher® 2 with spread spectrum frequency modulation featuring the LT8644S. The demo board is designed for 1.2V output from a 2.7V to 8V input. The LT8644S is a compact, ultralow emission, high efficiency, and high speed synchronous monolithic stepdown switching regulator. The integrated bypass capacitors optimize all 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 low as 20ns allows high step-down conversion even at high frequency. The LT8644S switching frequency can be programmed either via an external resistor or an external clock over a 300kHz to 3.5MHz range. The default frequency of demo circuit 2779A is 2MHz. The SYNC/MODE pin on the demo board DC2779A 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 in the demo manual). Figure 4 in the demo manual shows the efficiency of the circuit at 3.3V input and 5V input in force continuous mode operation (input from VIN terminal). To get accurate efficiency measurement, measure the input voltage at the VIN_SENSE/GND terminals and measure the output voltage at the VOUT+ SENSE/VOUT– SENSE terminals. Figure 5 shows the LT8644S temperature rise on DC2779A demo board at 3.3V input and 5V input in forced continuous mode. The LT8644S is assembled in a 4mm × 4mm LQFN package with exposed pads for low thermal resistance. The rated maximum continuous load current is 16A, while derating may be necessary for certain input voltage and thermal conditions. The demo board has an EMI filter installed. This EMI filter can be included by applying the input voltage at the VEMI terminal. The EMI performance of the board (with EMI filter) is shown on Figure 6 in the demo manual. The red lines in EMI Performance are CISPR25 Class 5 limits. The figure shows that the LT8644S circuit passes the test with a wide margin. To achieve EMI performance as shown in Figure 6, the input EMI filter is required and the input voltage should be applied to VEMI 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 LT8644S data sheet gives a complete description of the part, the operation and application information. The data sheet must be read in conjunction with the demo manual for demo circuit 2779A. 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. Contact ADI applications engineer for support.

Demonstration circuit 2786A is a single output high voltage non-isolated synchronous step-down converter that drives an all N-channel MOSFET power stage. It features the LTC7800, a low quiescent current high frequency (programmable fixed frequency from 320kHz up to 2.25MHz) synchronous step-down DC/DC controller housed in a small 3mm x 4mm QFN package. This DC2786A operates over an input voltage range from 8V to 40V, while the LTC7800 can operate up to 60V. This demo board produces a 3.3V output voltage with up to 10A output current, and is configured with a sense resistor for current sensing. A mode selector allows the DC2786A to operate in forced continuous operation, pulse-skipping or Burst Mode® operation during light loads. The LTC7800 features two integrated 5V gate drivers with 20ns deadtime which is good for GaN transistors or logic-level MOSFETs to maximize efficiency. The EXTVCC pin permits the LTC7800 to be powered from the output of the switching regulator or other available source, reducing power dissipation and improving efficiency. Please refer to the LTC7800 data sheet for a complete description of the part operation and application information.

Demonstration circuit 2788A is a boost LED driver featuring the LT®3950. This demonstration circuit powers a string of LEDs at 330mA. The step-up topology can be used to drive a string of up to 28V of LEDs as assembled. The maximum output voltage capability of the LT3950 is 60V. DC2788A runs from an input voltage range of 6V to 24V as built. It also runs at 2MHz and has the capability to turn on spread spectrum frequency modulation (SSFM) for a frequency range of 2.0MHz to 2.5MHz. Dimming control can be achieved with analog dimming or PWM dimming—either from an external or internally-generated clock source. DC2788A features undervoltage lockout (UVLO) set at 6.6V with a 1.0V hysteresis for turn-on. The UVLO voltage, LED current, output voltage range, switching frequency, brightness control, SSFM, and the topology can all be adjusted with simple modifications to the demonstration circuit. LT3950 is a monolithic 1.5A peak switch current, 60V LED driver. The guaranteed peak switch current rating of the IC is 1.5A and this is important to know when calculating maximum output current at a given LED voltage and input voltage for a boost converter. The LT3950 features SSFM and a well-controlled SW node for low emissions. A frequency range of 200kHz to 2MHz and a high-side PWMTG PWM-dimming MOSFET makes this a very versatile IC for many applications. It can be used for boost, buck-boost mode and buck mode LED driver applications. The PWMTG MOSFET not only provides high PWM dimming ratio capability, but it also serves as a short-circuit protection device. The FAULT flag indicates when there is either a short-circuit or open-LED fault at the output. The demo circuit is designed to be easily reconfigured to suit other applications, including the example schematics in the data sheet. Consult technical support for assistance. High voltage operation, 3V input voltage operation, multiple topologies, small-and-compact size, fault protection, low EMI, and multiple brightness control options make the LT3950 flexible and powerful for compact, noise-sensitive LED driver solutions. The LT3950JMSE featured on this demo circuit is available in a thermally enhanced 16-lead plastic MSOP package. The LT3950 data sheet must be read in conjunction with this demo manual to properly use or modify demo circuit DC2788A.

Demonstration circuit 2807A features the LTC6560 single channel transimpedance amplifier (TIA) with output multiplexing. The DC2807A accepts voltage pulses and converts them to current for the TIA. The LTC6560, which features 74kΩ transimpedance gain and 30µA linear input current range, is ideal for LIDAR receivers using avalanche photodiodes (APD). The LTC6560 operates from 5V single supply and consumes only 90mW. Utilizing the LTC6560’s output MUX, multiple LTC6560 devices can combine into a single output. The LTC6560’s fast overload recovery makes it well suited for LIDAR receivers. The LTC6560’s single-ended output can swing 2VP-P into a 100Ω load. The LTC6560 is packaged in a compact 3mm × 3mm 16-pin leadless QFN package with an exposed pad for thermal management and low inductance.

The LT3758/LT3758A are wide input range, current mode, DC/DC controllers which are capable of generating either positive or negative output voltages. They can be configured as either a boost, flyback, SEPIC or inverting converter. The LT3758/LT3758A drive a low side external N-channel power MOSFET from an internal regulated 7.2V supply. The fixed frequency, current-mode architecture results in stable operation over a wide range of supply and output voltages.The operating frequency of LT3758/LT3758A can be set with an external resistor over a 100kHz to 1MHz range, and can be synchronized to an external clock using the SYNC pin. A minimum operating supply voltage of 5.5V, and a low shutdown quiescent current of less than 1?A, make the LT3758/LT3758A ideally suited for batterypowered systems.The LT3758/LT3758A feature soft-start and frequency foldback functions to limit inductor current during start-up and output short-circuit. The LT3758A has improved load transient performance compared to the LT3758.APPLICATIONS Automotive Telecom Industrial

DC1446A: Demo Board for the LTC6909 1 to 8 Output, Multiphase Silicon Oscillator with Spread Spectrum Modulation.

Demonstration circuit 1471 is a monolithic step-down DC/DC switching regulator featuring the LT3990. The switching frequency is adjustable up to 2.2MHz. The demo circuit is designed for 5V, 350mA output from a 6.5V to 62V input. The wide input range of the LT3990 allows a variety of input sources including automotive batteries and 24V industrial supplies. Low ripple Burst Mode increases the efficiency at the light load while keeping the output ripple below 5mV in a typical application. The part is in shutdown when the EN pin is low and active when the pin is high. The threshold of the EN pin is accurate at 1V when VIN is above 4.2V. Adding a resistor divider from VIN to EN can program the LT3990 to regulate the output only when VIN is above a desired voltage. The catch diode and boost diode are integrated to reduce the components count and solution size. The circuit consumes only 2.5μA of quiescent current.

DC1503A-A: Demo Board for the LTM2881 Complete Isolated RS485/RS422 µModule Transceiver Plus Power.

The LTC2977 is an 8-channel Power System Manager used to sequence, trim (servo), margin, supervise, manage faults, provide telemetry and create fault logs. PMBus commands support power supply sequencing, precision point-of-load voltage adjustment and margining. DACs use a proprietary soft-connect algorithm to minimize supply disturbances. Supervisory functions include overvoltage and undervoltage threshold limits for eight power supply output channels and one power supply input channel, as well as over and under temperature limits. Programmable fault responses can disable the power supplies with optional retry after a fault is detected. Faults that disable a power supply can automatically trigger black box EEPROM storage of fault status and associated telemetry. An internal 16-bit ADC monitors eight output voltages, one input voltage, and die temperature. In addition, odd numbered channels can be configured to measure the voltage across a current sense resistor. A programmable watchdog timer monitors microprocessor activity for a stalled condition and resets the microprocessor if necessary. A single wire bus synchronizes power supplies across multiple LTC Power System Management (PSM) devices. Configuration EEPROM with ECC supports autonomous operation without additional software.APPLICATIONS Computers and Network Servers Industrial Test and Measurement High Reliability Systems Medical Imaging Video

The LTC4365 protects applications where power supply input voltages may be too high, too low or even negative. It does this by controlling the gate voltages of a pair of external N-channel MOSFETs to ensure that the output stays within a safe operating range.The LTC4365 can withstand voltages between ?40V and 60V and has an operating range of 2.5V to 34V, while consuming only 125?A in normal operation.Two comparator inputs allow configuration of the overvoltage (OV) and undervoltage (UV) set points using an external resistive divider. A shutdown pin provides external control for enabling and disabling the MOSFETs as well as placing the device in a low current shutdown state. A fault output provides status of the gate pin pulling low. A fault is indicated when the part is in shutdown or the input voltage is outside the UV and OV set points.The LTC4365 has a 36ms turn-on delay that debounces live connections and blocks 50Hz to 60Hz AC power. For fast recovery after faults, the LTC4365-1 has a reduced 1ms turn-on delay.Applications Portable Instrumentation Industrial Automation Laptops Automotive Surge Protection