DC1213A: Demo Board for the LTC3523 Synchronous 600mA Step-Up and 400mA Step-Down DC/DC Converters

The LT3495/LT3495B/LT3495-1/LT3495B-1 are low noise boost converters with integrated power switch, feedback resistor and output disconnect circuitry. The parts control power delivery by varying both the peak inductor current and switch off-time. This novel* control scheme results in low output voltage ripple as well as high efficiency over a wide load range. For the LT3495/LT3495-1, the off-time of the switch is not allowed to exceed a ?xed level, guaranteeing the switching frequency stays above the audio band for the entire load range. The parts feature a high performance NPN power switch with a 650mA and 350mA current limit for the LT3495/LT3495B and LT3495-1/LT3495B-1 respectively. The quiescent current is a low 60?A, which is further reduced to 0.1?A in shutdown. The internal disconnect circuitry allows the output voltage to be isolated from the input during shutdown. An auxiliary reference input (CTRL pin) overrides the internal 1.235V feedback reference with any lower value allowing full control of the output voltage during operation. The LT3495 series are available in a tiny 10-lead 3mm ? 2mm DFN package.Applications OLED Power Low Noise Power MP3 Player

The LTC3225/LTC3225-1 are programmable supercapacitor chargers designed to charge two supercapacitors in series to a selectable fixed output voltage (4.8V/5.3V for the LTC3225 and 4V/4.5V for the LTC3225-1) from input supplies as low as 2.8V to 5.5V. Automatic cell balancing prevents overvoltage damage to either supercapacitor. No balancing resistors are required. Low input noise, low quiescent current and low external parts count (one flying capacitor, one bypass capacitor at VIN and one programming resistor) make the LTC3225/LTC3225-1 ideally suited for small battery-powered applications. Charge current level is programmed with an external resistor. When the input supply is removed, the LTC3225/LTC3225-1 automatically enter a low current state, drawing less than 1?A from the supercapacitors. The LTC3225/LTC3225-1 are available in a 10-lead 2mm ? 3mm DFN package.Applications Current Limited Applications with High Peak Power Loads (LED Flash, PCMCIA Tx Bursts, HDD Bursts, GPRS/GSM Transmitter) Backup Supplies

Demonstration Circuit 1227A is a wide VIN, high efficiency, fixed frequency synchronous Buck-Boost converter using the LTC3534EDHC. The LTC3534EDHC topology operates with input voltages above, below or equal to the output voltage, making the product ideal for multi-cell Alkaline/NiMH or single Lithium Ion/Polymer applications where the output voltage is within the battery voltage range. The LTC3534EDHC operates with a 2.4V to 7V input voltage range and a VOUT range of 1.8V to 7V. The demonstration board has been designed to operate with VIN from 3.6V to 7V and VOUT is set to 5V with an output current up to 500mA.

The LT3573 is a monolithic switching regulator specifically designed for the isolated flyback topology. No third winding or opto-isolator is required for regulation. The part senses the isolated output voltage directly from the primary-side flyback waveform. A 1.25A, 60V NPN power switch is integrated along with all control logic into a 16-lead MSOP package.The LT3573 operates with input supply voltages from 3V to 40V, and can deliver output power up to 7W with no external power devices.The LT3573 utilizes boundary mode operation to provide a small magnetic solution with improved load regulation.Applications Industrial, Automotive and Medical Isolated Power Supplies

Demonstration circuit 1294A exercises four adjustable linear regulators in parallel using the LT3080. A small 20 mΩ ballast resistor is required for parallel operation. A short PCB trace can easily serve that purpose. The paralleled devices provide up to 4.4A of output current at 3.3V. Architected as a precision current source and voltage follower, the LT3080 can be used in many applications requiring high current, adjustability to zero output, and no heat sink. The device brings out the collector of the pass transistor to allow low dropout operation when used with multiple supplies. The LT3080's output voltage can be programmed to any level between 0V and 36V; however the demo board has a reduced input voltage range from 3.8V to 25V due to the input capacitor voltage rating.

Demonstration circuit DC1297B features the LTM4612EV, an EN55022 Class B certified synchronous step-down power module. The board accepts an input voltage from 5V to 36V and delivers a jumper programmable output voltage of 3.3V, 5V or 12V. The rated load current is 5A for 3.3V and 5V output voltages, or 3A for a 12V output. Current derating is necessary for certain VIN, VOUT, and thermal conditions.

The LTC3612 is a low quiescent current monolithic synchronous buck regulator using a current mode, constant frequency architecture. The no-load DC supply current in sleep mode is only 70?A while maintaining the output voltage (Burst Mode operation) at no load, dropping to zero current in shutdown. The 2.25V to 5.5V input supply voltage range makes the LTC3612 ideally suited for single Li-Ion as well as fixed low voltage input applications. 100% duty cycle capability provides low dropout operation, extending the operating time in battery-powered systems.The operating frequency is externally programmable up to 4MHz, allowing the use of small surface mount inductors. For switching noise-sensitive applications, the LTC3612 can be synchronized to an external clock at up to 4MHz.Forced continuous mode operation in the LTC3612 reduces noise and RF interference. Adjustable compensation allows the transient response to be optimized over a wide range of loads and output capacitors.The internal synchronous switch increases efficiency and eliminates the need for an external catch diode, saving external components and board space. The LTC3612 is offered in a leadless 20-pin 3mm ? 4mm QFN or a thermally enhanced 20-pin TSSOP package.APPLICATIONS Point-of-Load Supplies Distributed Power Supplies Portable Computer Systems DDR Memory Termination Handheld Devices

Demonstration circuit 1311 is a Telecom isolated DC/DC converter featuring the LTC3805/-5 constant frequency current mode flyback controller. The DC1311 converts 18V to 72V input voltage to an isolated 3A of output current at 3.3V. The 300kHz constant frequency operation is maintained down to very light load to reduce low frequency noise generated over a wide range of load current. The converter provides high output voltage accuracy (typically ±2%) over wide load range with no minimum load requirement. The DC1311 also provides non-isolated design by removing opto coupler and LTC4430 circuit. The demonstration circuit can be easily modified to generate different output voltages up to 15V. As output voltage is increased, the maximum output current must be reduced to limit the output power to no more than 10W.

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