The LTC3871/LTC3871-1 is a high performance bidirectional buck or boost switching regulator controller that operates in either buck or boost mode on demand. It regulates in buck mode from VHIGH-to-VLOW and boost mode from VLOW-to-VHIGH depending on a control signal, making it ideal for 48V/12V automotive dual battery systems. An accurate current programming loop regulates the maximum current that can be delivered in either direction. The LTC3871/LTC3871-1 allows both batteries to supply energy to the load simultaneously by converting energy from one battery to the other.Its proprietary constant-frequency current mode architecture enhances the signal-to-noise ratio enabling low noise operation and provides excellent current matching between phases. Additional features include discontinuous or continuous mode of operation, OV/UV monitors, independent loop compensation for buck and boost operation, accurate output current monitoring and overcurrent protection. The LTC3871 and LTC3871-1 have different current limit foldback characteristics.Applications Automotive 48V/12V Dual Battery Systems Backup Power Systems

Demonstration circuit 2351A is a high voltage, high efficiency synchronous buck or boost DC/DC converter. It is designed to have 36V to 56V on one side and 8V to 14V on the other side. It can supply a 35A maximum output current in buck mode and delivers 7A of current in boost mode. The demo board features the LT8228EFE controller. This part can seamlessly transition from bucking to boosting. With built-in circuit breaker function and other protection features, the LT8228 is ideal for high reliability systems requiring N+1 redundancy or other protections in industrial, automotive, medical, military, and avionics applications. The DC2351A is designed to be paralleled with other DC2351A boards to increase the total output current. With adequate heatsinking or airflow, the output current can be increased.

Demonstration circuit 2362A is an adjustable 3A linear regulator featuring the LT3033. The LT3033 is a very low dropout voltage (VLDO™) linear regulator that operates from a single input supply down to 0.95V. The device supplies 3A output current with 95mV typical dropout voltage. The LT3033 is ideal for low input voltage to low output voltage applications, providing comparable electrical efficiency to a switching regulator. The LT3033 optimizes stability and transient response with low ESR ceramic output capacitors as small as 10µF. A 10nF bypass capacitor at REF/BYP pin typically reduces output voltage noise to 60µVRMS in a 10Hz to 100kHz bandwidth. Soft-start time is directly proportional to the REF/BYP capacitor value. The LT3033’s current limit, accurate to ±12% over a wide input voltage and temperature range, can be programmed by a single resistor. When the input-to-output differential voltage exceeds 5V, foldback current limit lowers the internal current limit level, which may override the external programmable current limit. LT3033 has a PWRGD pin which indicates when the ADJ pin is within 8% of its nominal value. By connecting an external pull-up resistor from PWRGD to either the IN or OUT pin, PWRGD is pulled low when the output falls below 90.1% of the regulated voltage. As the output voltage rises above 92% of its regulated voltage, the PWRGD pin voltage is pulled up. The LT3033 features output current monitoring by connecting a resistor from the IMON pin to GND. The IMON pin is the collector of a PNP current mirror that outputs 1/2650th of the power PNP current. This circuitry is active for VIMON ≤ (VOUT – 400mV). The LT3033 also features shutdown, reverse-battery protection, thermal limiting with hysteresis and reverse current protection. The LT3033 is available as an adjustable device with an output voltage down to the 200mV reference. The device is available in a thermally enhanced, low profile 3mm × 4mm × 0.75mm QFN package. The LT3033 data sheet gives a complete description of the part, operation and application information. The data sheet must be read in conjunction with this quick start guide for demo circuit 2362A.

Demonstration circuit 2374A is a multi-chemistry battery charger with optional maximum power point tracking (MPPT) featuring the LTC4013. The LTC4013 has configurable 3 stage and 4 stage lead acid and Li-Ion battery algorithms in addition to 2 stage CC/CV charge cycles. The DC2374A is set up to operate from a 21.5V to 35V supply or from a solar panel and charges a six cell lead acid battery at 5A. It also can be configured to operate down to 5V. There are optional input and output capacitors plus large inductor pads and parallel top and bottom FET pads to allow high power charging. The operating frequency, charge voltage, low battery (LB) voltage setting and timing are configurable with external resistors and a capacitor. The different charging algorithms are jumper-selectable, set by two tri-state mode pins and the TIMER pin.

Demonstration Circuit 2375A is a dual output 350mA step down charge pump with a post-regulator LDO and watchdog timer featuring the LTC3256EMSE. The LTC3256 operates with a wide input voltage range from 5.5V to 38V and is engineered for diagnostic coverage in ISO262262 systems. The LTC3256 can provide up to 350mA of output current from a 12V battery with 2W less power dissipation than 2 ideal linear regulators. The DC2375A was populated with automotive grade components for evaluation. Because of the wide input operating range it is possible to exceed the specified operating junction temperature and even reach thermal shutdown with heavy loads. Please refer to the data sheet for additional information on the thermal limitations of the device.

Demonstration circuit 2397A features the LTC3130-1, a wide input voltage, wide output voltage operating range, high efficiency, low noise monolithic DC/DC buck-boost converter that provides 600mA of output current when in buck mode. The LTC3130-1 has 4-pin selectable output voltages (1.8V, 3.3V, 5V and 12V) and operates from input voltages of 2.4V to 25V. The LTC3130-1 incorporates a proprietary low noise switching algorithm which optimizes efficiency with input voltages above, below, or equal to the output voltage and ensures seamless transitions between operating modes.

The LTC7812 is a high performance synchronous Boost+Buck DC/DC switching regulator controller that drives all N-channel power MOSFET stages. It contains independent step-up (boost) and step-down (buck) controllers that can regulate two separate outputs or be cascaded to regulate an output voltage from an input voltage that can be above, below or equal to the output voltage. The LTC7812 operates from a wide 4.5V to 38V input supply range. When biased from the output of the boost regulator, the LTC7812 can operate from an input supply as low as 2.5V after start-up. The 33?A no-load quiescent current extends operating run time in battery-powered systems.Unlike conventional buck-boost regulators, the LTC7812?s cascaded Boost+Buck solution has continuous, nonpulsating, input and output currents, substantially reducing voltage ripple and EMI. The LTC7812 has independent feedback and compensation points for the boost and buck regulation loops, enabling a fast output transient response that can be easily optimized externally.Applications Automotive and Industrial Power Systems High Power Battery Operated Systems

The ADM1075 is a full feature, negative voltage, hot swap controllerwith constant power foldback and high accuracy digital currentand voltage measurement that allows boards to be safely insertedand removed from a live -48 V backplane. The part providesprecise and robust current limiting and protection against bothtransient and nontransient short circuits and overvoltage andundervoltage conditions. The ADM1075 typically operates froma negative voltage of -35 V to -80 V and, due to shunt regulation,has excellent voltage transient immunity. The operating range ofthe part is flexible due to the shunt regulator, and the part can bepowered directly by a 10 V rail to save shunt power dissipation(see the Powering the ADM1075 section for more details).A full-scale current limit of 25 mV or 50 mV can be selected bychoosing the appropriate model. The maximum current limit isset by the combination of the sense resistor, RSENSE, and the inputvoltage on the ISET pin, using external resistors. This allows finetuning of the trip voltage so that standard sense resistors can beused. Inrush current is limited to this programmable value bycontrolling the gate drive of an external N-channel FET. A builtinsoft start function allows control of the inrush current profile byan external capacitor on the soft start (SS) pin.Refer to the datasheet for more information.PRODUCT HIGHLIGHTS Constant Power Foldback. Maximum FET power set by a PLIM resistor divider. This eases complexity when designing to maintain FET SOA. Adjustable Current Limit. The current limit is adjustable via the ISET pin allowing for the use of a standard value sense resistor. 12-Bit ADC. Accurate voltage, current, and power measurements. Also enables calculation of energy consumption over time. PMBus Interface. PMBus fast mode compliant interface used to read back status and data registers and set warning and fault limits. Fault Recording. Latched status registers provide useful debugging information to help trace faults in high reliability systems. Built-In Soft Start. Soft start capacitor controls inrush current profile with di/dt control.APPLICATIONS Telecommunication and data communication equipment Central office switching -48 V distributed power systems Negative power supply control High availability servers

The ADM1166 Super Sequencer? is a configurable supervisory/ sequencing device that offers a single-chip solution for supply monitoring and sequencing in multiple-supply systems. In addition to these functions, the ADM1166 integrates a 12-bit ADC and six 8-bit voltage output DACs. These circuits can be used to implement a closed-loop margining system that enables supply adjustment by altering either the feedback node or reference of a dc-to-dc converter using the DAC outputs.Supply margining can be performed with a minimum of external components. The margining loop can be used for in-circuit testing of a board during production (for example, to verify board func-tionality at ?5% of nominal supplies), or it can be used dynamically to accurately control the output voltage of a dc-to-dc converter. APPLICATIONS Central office systems Servers/routers Multivoltage system line cards DSP/FPGA supply sequencing In-circuit testing of margined supplies

The ADM1278 is a hot swap controller that allows a circuit board to be removed from or inserted into a live backplane. It also features current, voltage, power, and temperature readback via an integrated 12-bit analog-to-digital converter (ADC), accessed using a PMBus? interface. The load current is measured using an internal current sense amplifier that measures the voltage across a sense resistor in the power path via the HS+ and HS? pins. A default current limit of 20 mV is set, but this limit can be adjusted, if required.The ADM1278 limits the current through the sense resistor by controlling the gate voltage of an external N-channel FET in the power path, via the GATE pin. The sense voltage, and therefore the load current, is maintained below the preset maximum. The ADM1278 protects the external FET by limiting the time that the FET remains on while the current is at its maximum value.This current-limit time is set by the choice of capacitor connected to the TIMER pin. In addition, a constant power foldback scheme is used to control the power dissipation in the MOSFET during power-up and fault conditions. The level of this power, along with the TIMER regulation time, can be set to ensure that the MOSFET remains within safe operating area (SOA) limits.In case of a short-circuit event, a fast internal overcurrent detector responds within 320 ns and signals the gate to shut down. A 1500 mA pull-down device ensures a fast FET response.The ADM1278 features overvoltage (OV) and undervoltage (UV) protection, programmed using external resistor dividers on the UV and OV pins. A PWRGD signal can be used to detect when the output supply is valid, using the PWGIN pin to accurately monitor the output.The ADM1278 is available in a 32-lead LFCSP with a RETRY pin that can be configured for automatic retry or latch-off when an overcurrent fault occurs.Applications Servers Power monitoring and control/power budgeting Telecommunication and data communication equipment?