The LT3478/LT3478-1 are 4.5A step-up DC/DC converters designed to drive LEDs with a constant current over a wide programmable range. Series connection of the LEDs provides identical LED currents for uniform brightness without the need for ballast resistors and expensive factory calibration.The LT3478-1 reduces external component count and cost by integrating the LED current sense resistor. The LT3478 uses an external sense resistor to extend the maximum programmable LED current beyond 1A and also to achieve greater accuracy when programming low LED currents. Operating frequency can be set with an external resistor from 200kHz up to 2.25MHz. Unique circuitry allows a PWM dimming range up to 3000:1 while maintaining constant LED color. The LT3478/LT3478-1 are ideal for high power LED driver applications such as automotive TFT LCD backlights, courtesy lighting and heads-up displays. One of two CTRL pins can be used to program maximum LED current. The other CTRL pin can be used to program a reduction in maximum LED current vs temperature to maximize LED usage and improve reliability.Additional features include inrush current protection, programmable open LED protection and programmable soft-start. Each part is available in a 16-pin thermally enhanced TSSOP Package.Applications High Power LED Driver Automotive Lighting

DC954A-B: Demo Board for the LT6402-12 300MHz Low Distortion, Low Noise Differential Amplifier/ADC Driver (AV = 12dB).

Demonstration Circuit 974 is a 100kHz to -500kHz programmable frequency, high voltage, current-mode DC/DC step-down converter featuring the LT3844. The operating frequency can be synchronized up to 600kHz. The board operates from a Vin range of 15V to -60V and outputs 12VOUT @ 4.2A (50W).

Demonstration circuit 976 is a Quadruple High Power LED Driver in Buck Mode featuring the LT3476EUHF. The LT3476 is a quad output, multitopology DC/DC converter designed to operate as a current source for driving high current LEDs. Each of the four regulators on the demo circuit is independently operated. The VIN power supply for the IC ranges from 2.8V to 16V. The PVIN power supply for the buck regulators ranges up to 33V. On the demo circuit, the default current for each output channel is 350mA but it can be adjusted up to 1.05A via resistor dividers at the VADJ pins. The output current should not exceed the rated current of the LEDs used. If 1W LEDs, such as the Lumileds Luxeon LEDs, are used, 350mA current is the maximum. 1A output current is reserved for 3W LEDs, such as Luxeon III. The input voltage is limited by the CAP pin overvoltage protection threshold. As a result, each channel of the demo circuit can drive up to 27V total LED voltage.

The LTC4245 Hot Swap? controller allows a board to be safely inserted and removed from a live backplane in multiple supply systems such as CompactPCI and PCI Express. Using four external N-channel pass transistors, the board supply voltages can be ramped up at an adjustable rate and in any desired sequence. An I2C interface and on-board ADC allow monitoring of board current, voltage and fault status for each supply.The device features adjustable dI/dt controlled soft start and foldback limited inrush current. A dual-level timed circuit breaker and fast current limit protect each supply against overcurrent faults. A power good input with timeout allows a downstream supply monitor to disconnect the board supplies. The device can be con?gured to function without a ?12V supply or with an extra 3.3V supply instead of a 5V supply.The controller has additional features to interrupt the host when a fault has occurred, notify when output power is good, detect insertion of a load card and power-up in either the on or off state.Applications Live Board Insertion CompactPCI, CompactPCI Express, CompactTCA, PCI Express Systems

The ADM1184 is an integrated, 4-channel voltage-monitoring device. A 2.7 V to 5.5 V power supply is required on the VCC pin to power the device.Four precision comparators monitor four voltage rails. Each comparator has a 0.6 V reference with a worst-case accuracy of 0.8%. Resistor networks that are external to the VIN1, VIN2, VIN3, and VIN4 pins set the trip points for the monitored supply rails.The ADM1184 has four open-drain outputs. Of these outputs, OUT1 to OUT3 can be used to enable power supplies, and PWRGD is a common power-good output indicating that all monitored supplies are above their respective thresholds.OUT1 to OUT3 are dependent on their associated VINx input (that is, VIN1, VIN2, or VIN3). If a supply monitored by VINx drops below its programmed threshold, the associated OUTx pin and PWRGD are disabled.PWRGD is a common power-good output indicating the status of all monitored supplies. There is an internal 190 ms (typical) delay associated with the assertion of the PWRGD output. If VIN1, VIN2, VIN3, or VIN4 drops below its programmed threshold, PWRGD is deasserted immediately.The ADM1184 is available in a 10-lead mini small outline package (MSOP).APPLICATIONS Monitor and alarm functions Telecommunications Microprocessor systems PC/servers

The ADM1186-1 and ADM1186-2 are integrated, four-channel, voltage monitoring and sequencing devices. A 2.7 V to 5.5 V power supply is required on the VCC pin for power.Four precision comparators monitor four voltage rails, with all comparators sharing a 0.6 V reference and a worst-case accuracy of 0.8%. Resistor networks that are external to the VIN1, VIN2, VIN3, and VIN4 pins set the Under Voltage (UV) trip points for the monitored supply rails.The ADM1186-1 and ADM1186-2 have four open drain enable outputs, OUTx, that are used to enable power supplies. An open drain power good output, PWRGD, is provided that indicatesthe four VINx inputs are above their UV thresholds.A state machine monitors the state of the UP and?DOWN pins on the ADM1186-1 or the UP/overbar: DOWN pin on the ADM1186-2 to control the supply sequencing direction. In the ?Wait Start?state, a rising edge transition on the UP or UP/DOWN pin triggers a power-up sequence. A falling edge transition on the DOWN or UP/DOWN pin in the ?Power Up Done? statetriggers a power down sequence.During a power up sequence, the state machine enables each power supply in turn. The supply output voltage is monitored to determine if it rises above the UV threshold level within a userdefined duration called the blanking time. If a supply rises above the UV threshold then the next enable output in the sequence is turned on. In addition to the blanking time a user may also define sequencing time delays between each enable output turning on. When all four enable outputs are on, and the four VINx pins are above their UV trip points the power up sequence is complete. The ADM1186-1 provides an open drain pin, SEQ_DONE, that is asserted high to provide an indication that an up sequence is complete. The SEQ_DONE pins is allows multiple cascadedADM1186-1 devices to be perform controlled power up and down sequences. During a power down sequence the enable outputs turn off inreverse order. The sequence time delays between successive supplies the same as during the power up sequence, and no blanking time is used during a power down sequence. At the end of a down sequence the SEQ_DONE pin is brought low. During sequencing and when powered up, the state machine continuously monitors for any fault conditions. Faults include a UV condition on any of the inputs, or an unexpected controlinput. Any fault that occurs causes the state machine to enter a fault handler. This immediately turns off all enable outputs, and ensures that the device is ready to start a new up sequence. The ADM1186-1 has a bi-directional open drain pin, FAULT, that facilitates fault handling when using multiple devices. An ADM1186-1 experiencing a fault condition drives the FAULT pin low, causing other connected ADM1186-1devices to enter their own fault handling state.The ADM1186-1 is available in a 20-lead QSOP package andthe ADM1186-2 is available in a 16-lead QSOP package.

The ADM1186-1 and ADM1186-2 are integrated, four-channel, voltage monitoring and sequencing devices. A 2.7 V to 5.5 V power supply is required on the VCC pin for power.Four precision comparators monitor four voltage rails, with all comparators sharing a 0.6 V reference and a worst-case accuracy of 0.8%. Resistor networks that are external to the VIN1, VIN2, VIN3, and VIN4 pins set the Under Voltage (UV) trip points for the monitored supply rails.The ADM1186-1 and ADM1186-2 have four open drain enable outputs, OUTx, that are used to enable power supplies. An open drain power good output, PWRGD, is provided that indicatesthe four VINx inputs are above their UV thresholds.A state machine monitors the state of the UP and?DOWN pins on the ADM1186-1 or the UP/overbar: DOWN pin on the ADM1186-2 to control the supply sequencing direction. In the ?Wait Start?state, a rising edge transition on the UP or UP/DOWN pin triggers a power-up sequence. A falling edge transition on the DOWN or UP/DOWN pin in the ?Power Up Done? statetriggers a power down sequence.During a power up sequence, the state machine enables each power supply in turn. The supply output voltage is monitored to determine if it rises above the UV threshold level within a userdefined duration called the blanking time. If a supply rises above the UV threshold then the next enable output in the sequence is turned on. In addition to the blanking time a user may also define sequencing time delays between each enable output turning on. When all four enable outputs are on, and the four VINx pins are above their UV trip points the power up sequence is complete. The ADM1186-1 provides an open drain pin, SEQ_DONE, that is asserted high to provide an indication that an up sequence is complete. The SEQ_DONE pins is allows multiple cascadedADM1186-1 devices to be perform controlled power up and down sequences. During a power down sequence the enable outputs turn off inreverse order. The sequence time delays between successive supplies the same as during the power up sequence, and no blanking time is used during a power down sequence. At the end of a down sequence the SEQ_DONE pin is brought low. During sequencing and when powered up, the state machine continuously monitors for any fault conditions. Faults include a UV condition on any of the inputs, or an unexpected controlinput. Any fault that occurs causes the state machine to enter a fault handler. This immediately turns off all enable outputs, and ensures that the device is ready to start a new up sequence. The ADM1186-1 has a bi-directional open drain pin, FAULT, that facilitates fault handling when using multiple devices. An ADM1186-1 experiencing a fault condition drives the FAULT pin low, causing other connected ADM1186-1devices to enter their own fault handling state.The ADM1186-1 is available in a 20-lead QSOP package andthe ADM1186-2 is available in a 16-lead QSOP package.

The ADM1192 is an integrated current sense amplifier that offers digital current and voltage monitoring via an on-chip, 12-bit analog-to-digital converter (ADC), communicated through an I2C interface.An internal current sense amplifier senses voltage across the sense resistor in the power path via the VCC pin and the SENSE pin.A 12-bit ADC can measure the current seen in the sense resistor and in the supply voltage on the VCC pin. An industry-standard I2C interface allows a controller to read current and voltage data from the ADC. Measurements can be initiated by an I2C command. Alternatively, the ADC can run continuously, and the user can read the latest conversion data whenever it is required. Up to four unique I2C addresses can be created, depending on the way the ADR pin is connected.A SETV pin is also included. A voltage applied to this pin is internally compared to the output voltage on the current sense amplifier. The output of the SETV comparator asserts when the current sense amplifier output exceeds the SETV voltage. This event is detected at the ALERT block. The ALERT block then charges up the external TIMER capacitor with a fixed current. When this timing cycle is complete, the ALERT output asserts.The ALERT output can be used as a flag to warn a micro-controller or field programmable gate array (FPGA) of an overcurrent condition. ALERT outputs of multiple ADM1192 devices can be tied together and used as a combined alert.A basic P-channel FET hot swap circuit can be implemented with the ALERT output. The value of the TIMER capacitor should be set so that the charging time of this capacitor is much longer than the period where a higher than nominal inrush current may be flowing.The ADM1192 is packaged in a 10-lead MSOP.APPLICATIONS Power monitoring/power budgeting Central office equipment Telecommunication and data communication equipment PCs/servers

The ADM1293 and ADM1294 are high accuracy integrated digital power monitors that offer digital current, voltage, and power monitoring using an on-chip, 12-bit analog-to-digital converter (ADC), communicated through a PMBus? compliant I2C interface.These devices acquire the current by measuring the voltage difference across the external sense resistor. This voltage is amplified and digitized by an internal 12-bit ADC. The same ADC can also sample the primary input voltage and an auxiliary input voltage. The internal digital block can perform multiplication of the current and primary input voltage for power calculation. The ADM1293/ADM1294 also feature a power accumulator for energy metering. An industry-standard PMBus interface allows a master controller to read back these data from the device. The master controller can then combine this information with a known sense resistor value to calculate the current, voltage, power, and energy consumption over time on the monitored rail.In conditions such as overcurrent, overvoltage, undervoltage, and overpower, the ADM1293/ADM1294 devices can generate an interrupt signal to the microprocessor through the GPOx/ALERTx outputs. The threshold for these conditions is digitally programmed via PMBus.The ADM1293 is designed for high-side supply monitoring with a voltage monitoring range from 0 V to 20 V. The ADM1294 is designed for low-side supply monitoring. Its integrated shunt regulator allows it to be powered and to monitor supply in wide voltage ranges.The ADM1293/ADM1294 are available in 4 mm ? 4 mm 16-lead LFCSP and 14-lead TSSOP packages with a specified operating ambient temperature range from ?40?C to +105?C for the ADM1293 and an operating junction temperature range from ?40?C to +105?C for the ADM1294.Applications Power monitoring/power budgeting Central office equipment Telecommunications and data communications equipment PCs/servers