The DC2703A-A-KIT contains the DC2703A (LT8491demo board) and DC1613A (USB-to-I2C controller). Together they provide a high performance buck-boost battery charger converter with an I2C interface. The LT8491 implements a maximum power point tracking (MPPT) function and flexible charging profiles, suitable for most battery types such as flooded and sealed lead acid batteries and Li-Ion batteries. A Microsoft Windows-Based GUI (Graphical User Interface) application called “simpleLT8491” is provided which can be downloaded here. The DC2703A-A-KIT demo board is configured for 17V to 54V input voltage range and the power source can be a solar panel with 36 to 72 cells (up to 200W) or a DC voltage source. The LT8491 converter can operate from input voltages above, below or equal to the battery voltage. Two input connectors are provided. An ideal diode controller LTC4359 protects the DC power supply output from being back fed from the solar panel. This allows, for example, a 24VDC supply to be plugged in while a solar panel with higher voltage is being used to power the circuit. The DC2703A-A-KIT demo board output is set up for charging a 12V SLA battery with up to 16.6A charge current. The DC2703A-A-KIT demo board can be modified to support much higher output voltage, with modifications including higher voltage rating output side MOSFETs and capacitors. The LT8491 includes a slave I2C compatible interface for digital control of the charger settings and digital readouts of charger telemetry and status. A Microsoft Windows- Based GUI (Graphical User Interface) application is provided for this demo board, which makes it very easy to read charger telemetry and status data, as well as the ability to change the charging algorithm by writing to the appropriate configuration registers. The LT8491 EEPROM on the DC2703A-A-KIT demo board is programmed with the onboard resistor values to accurately read charger telemetry and status registers data. On-chip logic provides automatic true power point tracking (MPPT) for solar powered applications. The MPPT function not only continuously tracks the maximum power point, but also periodically sweeps the input panel voltage in order to select the correct maximum on the power curve. In doing so, an increase in power harvested from the panel during partial shade conditions is possible when multiple peaks occur on the power curve. During periods of low light, a low power mode allows the charger to deliver a small charge current even if there is not enough light for the MPPT function to operate. An RJ25 modular jack can be used to connect an external NTC temperature sensor mounted at the battery. This allows temperature compensation of the charge voltage, which is important for lead acid batteries. The same connector can be used for remote sensing of battery voltage, to compensate for voltage drops in long battery cables. The onboard LED displays the charge state. The LT8491 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 for DC2703A-A-KIT. The LT8491EUKJ is assembled in a 64-lead (7mm × 11mm) plastic QFN package with a thermal pad underneath the chip. Proper board layout is essential for maximum thermal performance.

The LTC4381 is an integrated solution for low quiescent current eFuse with an internal 9m? N-Channel MOSFET. Overvoltage protection is provided by clamping the gate voltage of an internal 9m? N-channel MOSFET to limit the output voltage to a safe value during overvoltage events such as load dump in automobiles. The MOSFET safe operating area is production tested and guaranteed for the stresses during high voltage transients. Fixed output clamp voltages are selectable for 12V and 24V/28V systems. For systems of any voltage up to 80V, use the adjustable clamp versions.Overcurrent protection is also provided. An internal multiplier generates a TMR pin current proportional to VDS and ID, so that operating time in both overcurrent and overvoltage conditions is limited in accordance with MOSFET stress.The GATE pin can drive back-to-back MOSFETs for reverse input protection, eliminating the voltage drop and dissipation of a Schottky diode solution. A low 6?A operating current permits use in always-on and battery powered applications.APPLICATIONS Automotive 12V, 24V and 48V System Avionic/Industrial Surge Protection Hot Swap/Live Insertion High Side Switch for Battery Powered Systems Automotive Load Dump Protection

The LTC4381 is an integrated solution for low quiescent current eFuse with an internal 9m? N-Channel MOSFET. Overvoltage protection is provided by clamping the gate voltage of an internal 9m? N-channel MOSFET to limit the output voltage to a safe value during overvoltage events such as load dump in automobiles. The MOSFET safe operating area is production tested and guaranteed for the stresses during high voltage transients. Fixed output clamp voltages are selectable for 12V and 24V/28V systems. For systems of any voltage up to 80V, use the adjustable clamp versions.Overcurrent protection is also provided. An internal multiplier generates a TMR pin current proportional to VDS and ID, so that operating time in both overcurrent and overvoltage conditions is limited in accordance with MOSFET stress.The GATE pin can drive back-to-back MOSFETs for reverse input protection, eliminating the voltage drop and dissipation of a Schottky diode solution. A low 6?A operating current permits use in always-on and battery powered applications.APPLICATIONS Automotive 12V, 24V and 48V System Avionic/Industrial Surge Protection Hot Swap/Live Insertion High Side Switch for Battery Powered Systems Automotive Load Dump Protection

Demonstration circuit 2719A is a high performance bidirectional buck-boost converter featuring the LT8708/ LT8708-1 that can operate from input voltages above, below or equal to the output voltage. The demo board input range is 10.5V to 14.5V (25VMAX). The output voltage is set at 14.5V and the output current limit at 40A. The board can operate in both forward and reverse mode. The controller has integrated input voltage and output voltage regulators and two sets of input and output current regulators that control current flow in forward or reverse direction. Features are included that simplify bidirectional power conversion in battery/capacitor backup systems and other applications that may need regulation of VIN, VOUT, IIN and/or IOUT. While the current mode control limits the inductor current both in normal and in reverse direction these current limits have some variation as input/output voltage changes. The forward and reverse input and output current regulators offer four accurate current limits that can be set individually. The input voltage regulator is often used in applications with high impedance power sources and will reduce the forward current if the input voltage drops below the set point. When operating with reverse current flow, the input voltage regulator regulates the voltage at the input side. The operating mode of the controller is determined through the MODE pin (jumper JP9 Pins 5 to 12) and can be set to discontinuous mode, hybrid discontinuous mode, forced continuous mode and Burst Mode® operation. The LT8708 is capable of bidirectional operation when operating in the continuous conduction mode (CCM). DCM, HCM and Burst Mode operation only allow power to flow in one direction. Additional circuitry may be needed depending on the application.

Demonstration circuit 2721A-B features the LTM4625EY μModule® regulator, a tiny high performance high efficiency step-down regulator configured as an inverting buck-boost regulator. DC2721A-B has an operating input voltage range of 4V to 15V and is able to provide an output current of up to 3A. The output voltage can be programmed from –0.6V and –5.5V. The LTM4625EY is a complete DC/DC point of load regulator in a thermally enhanced 6.25mm × 6.25mm × 5.01mm BGA package requiring only a few input and output capacitors. The LTM4625 data sheet must be read in conjunction with this demo manual for working on or modifying demo circuit 2721A-B.

The LTC2949 is a high precision current, voltage, temperature,?charge and energy meter for electrical and hybrid?vehicles and other isolated current sense applications. It?infers charge and energy flowing in and out of the battery?pack by monitoring simultaneously the voltage drop over?up to two sense resistors and the battery pack voltage.Low offset ?? ADCs ensure accurate measurement of?voltage and current with insignificant power loss. Continuous?integration of current and power ensures lossless?tracking of charge and energy delivered or received by?the battery pack.The built-in serial interface can be configured to support?isolated isoSPI communication to the host or as SPI?interface.The LTC2949 features 12 internally buffered high impedance?inputs (V1 to V12) for measuring voltages from?external sensors or resistor dividers allowing to measure?temperatures, HV-Link voltages, chassis isolation and?supervise contactor states. LTC2949 has up to five programmable?digital outputs which can be set to ground,?supply or toggling at 400kHz.Programmable threshold and tracking registers reduce?digital traffic to the host.Applications Electric and Hybrid Vehicles Isolated Current Sensing Backup Battery Systems High Power Portable Equipment

The LTC2949 is a high precision current, voltage, temperature,?charge and energy meter for electrical and hybrid?vehicles and other isolated current sense applications. It?infers charge and energy flowing in and out of the battery?pack by monitoring simultaneously the voltage drop over?up to two sense resistors and the battery pack voltage.Low offset ?? ADCs ensure accurate measurement of?voltage and current with insignificant power loss. Continuous?integration of current and power ensures lossless?tracking of charge and energy delivered or received by?the battery pack.The built-in serial interface can be configured to support?isolated isoSPI communication to the host or as SPI?interface.The LTC2949 features 12 internally buffered high impedance?inputs (V1 to V12) for measuring voltages from?external sensors or resistor dividers allowing to measure?temperatures, HV-Link voltages, chassis isolation and?supervise contactor states. LTC2949 has up to five programmable?digital outputs which can be set to ground,?supply or toggling at 400kHz.Programmable threshold and tracking registers reduce?digital traffic to the host.Applications Electric and Hybrid Vehicles Isolated Current Sensing Backup Battery Systems High Power Portable Equipment

Demonstration circuit DC2744 is a two stage DC/DC boost converter featuring the LTC7840, a constant frequency current mode boost controller. The DC2744A operates over a 9V to 36V input voltage range. The first stage boost generates VOUT1 at 48V. The second stage boost takes this 48V input and provides a 240V output with 0.7A of load current. The 150kHz constant frequency operation results in a small and efficient circuit. The converter provides high output voltage accuracy (typically ±3%) over a wide load range with no minimum load requirement. The demonstration circuit can be easily modified to generate different output voltages. The DC2744 has small circuit footprint. It is a high performance cost effective solution for applications that require high step-up voltage ratios and high output power.

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.

The LTC1662 is an ultralow power, fully buffered voltage output, dual 10-bit digital-to-analog converter (DAC). Each DAC channel draws just 1.7?A (typ) total supply-plus-reference operating current, yet is capable of supplying DC output currents in excess of 1mA and reliably driving capacitive loads of up to 1000pF. A programmable Sleep mode further reduces total operating current to 0.05?A. Linear Technology?s proprietary, inherently monotonic architecture provides excellent linearity and an exceptionally small external form factor. The double-buffered input logic provides simultaneous update capability and can be used to write to the DACs without interrupting Sleep mode. With its tiny operating current and exceptionally small size, the LTC1662 is ideal for use in the most power-constrained products. For most designs, there is no perceptible impact on the power budget; the LTC1662 draws many times less current than even a trimpot, while providing buffered, low impedance (0.5? typical, VCC = 5V) rail-to-rail outputs. The LTC1662 is pin and software compatible with the LTC1661 dual, 60?A 10-bit DAC. It is available in 8-pin MSOP and PDIP packages and is specified over the industrial temperature range.Applications Mobile Communications Portable Battery-Powered Instruments Remote or Inaccessible Adjustments Digitally Controlled Amplifiers and Attenuators Factory or Field Calibration