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6-12Vin to ±5V@50mA Split Supply
An easy-to-implement split-voltage power supply using the LTC3388 yields a low quiescent current, high efficiency solution for powering low current analog circuits that need a virtual ground output. The output voltage of each device is digitally programmable to four output voltages from 1.2V to 5.0V and will support a load current up to 50mA. Each regulator requires only four external capacitors and one inductor, covering minimal board real estate.
| January 2012 |
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Dual Output ±32V@5mA Converter
The LT1945 is a dual micropower DC/DC converter in a 10-pin MSOP package. Each converter is designed with a 350mA current limit and an input voltage range of 1.2V to 15V, making the LT1945 ideal for a wide variety of applications. Both converters feature a quiescent current of only 20μA at no load, which further reduces to 0.5μA in shutdown. A current limited, fi xed off-time control scheme conserves operating current, resulting in high efficiency over a broad range of load current.
| January 2012 |
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5V to ±12V@320mA Dual Supply Boost/Inverting Converter
The LT3471 dual switching regulator combines two 42V, 1.3A switches with error amplifi ers that can sense to ground providing boost and inverting capability. The low VCESAT bipolar switches enable the device to deliver high current outputs in a small footprint. The LT3471 switches at 1.2MHz, allowing the use of tiny, low cost and low profi le inductors and capacitors.
| January 2012 |
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5V to ±12V@80mA Split Supply
The LT3582 series includes two monolithic converters, one Boost and one Inverting. The Boost converter has an integrated power switch and output disconnect switch. The Inverting converter uses a single inductor topology and includes an integrated power switch. Both Boost and Inverting converters use a novel control scheme resulting in low output voltage ripple while allowing for high conversion efficiency over a wide load current range.
| January 2012 |
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5V to ±12V@550mA Split Supply at 1.5MHz
The LT8582 is a dual independent channel PWM DC/DC converter with a power good pin and built-in fault protection to help guard against input overvoltage and overtemperature conditions. Each channel consists of a 42V master switch and a 42V slave switch that can be tied together for a total current limit of 3A.
| January 2012 |
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±5V to ±15V Tracking Supply
The LT3032 is a dual, low noise, positive and negative low dropout voltage linear regulator. Each regulator delivers up to 150mA with a typical 300mV dropout voltage. Each regulator’s quiescent current is low (30μA operating and <3μA in shutdown) and well-controlled in dropout, making it an excellent choice for battery-powered circuits.
| January 2012 |
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Power Backup System Using Supercapacitors
This circuit shows a power holdup system that incorporates a supercapacitor stack with the capacity to provide standby power of 165mW for about 45 seconds in the absence of battery power. An LDO converts the output of the supercapacitor stack to a constant voltage supply during backup mode.
| January 2012 |
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Ultralow-EMI, 96W, Step-Down μModule Regulator— EN55022 Class B Certified in a 15mm x 15mm Footprint
The LTM4613 delivers high output power and efficiency with demonstrated EMI performance that complies with EN55022 Class B. With carefully designed integrated filter, meticulous internal layout, shielded inductor, internal snubber circuitry and power transistor driver, the LTM4613 achieves a perfect balance between the size, output power, efficiency and emission. The LTM4613 eliminates the need for external filters, magnetic shields, and ferrite beads for a trouble-free design process, making it easy to design safe, EMI-compliant power supplies.
| January 2012 |
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System Monitor with Instrumentation-Grade Accuracy Used to Measure Relative Humidity
A psychrometer is a type of hygrometer, a device that measures relative humidity. It uses two thermometers, one dry (dry bulb) and one covered in a fabric saturated with distilled water (wet bulb). Air is passed over both thermometers, either by a fan or by swinging the instrument, as in a “sling psychrometer.” A psychrometric chart is then used to calculate humidity from the dry and wet bulb temperatures. This circuit shows the LTC2991-based psychrometer. The two transistors provide the wet bulb and dry bulb temperature readings when connected to the appropriate inputs of the LTC2991.
| January 2012 |
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LTC6946-2 Driving a Passive Downconverting Mixer
The LTC6946 is a high performance, low noise, 5.7GHz phase-locked loop (PLL) with a fully integrated VCO, including a reference divider, phase-frequency detector (PFD) with phase-lock indicator, ultralow noise charge pump, integer feedback divider, and VCO output divider. The charge pump contains selectable high and low voltage clamps useful for VCO monitoring.
| January 2012 |
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Programmable Switching 1.5A Current Source
The LTC3600 is a high efficiency, monolithic synchronous buck regulator whose output is programmed with just one external resistor. The accurate internally generated 50μA current source on the ISET pin allows the use of a single external resistor to program an output voltage that ranges from 0V to 0.5V below VIN. The VOUT voltage feeds directly back to the error amplifier in unity gain fashion and equals the ISET voltage. The operating supply voltage range is 4V to 15V, making it suitable for dual lithium-ion battery and 5V or 12V input point-of-load power supply applications.
| January 2012 |
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LTC6945 Wideband Point-to-Point Radio Local Oscillator
The LTC6945 is a high performance, low noise, 6GHz phase locked loop (PLL), including a reference divider, phase frequency detector (PFD) with phase-lock indicator, charge pump, integer feedback divider and VCO output divider. The part features a buffered, programmable VCO output divider with a range of 1 through 6. The differential, low noise output buffer has user-programmable output power ranging from –6dBm to 3dBm, and may be muted through either a digital input pin or software.
| January 2012 |
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28V Vehicle Application with Reverse Voltage Protection
The LTC4366 surge stopper protects loads from high voltage transients. By controlling the gate of an external N-channel MOSFET, the LTC4366 regulates the output during an overvoltage transient. The load may remain operational while the overvoltage is dropped across the MOSFET. Placing a resistor in the return line isolates the LTC4366 and allows it to float up with the supply; therefore, the upper limit on the output voltage depends only on the availability of high valued resistors and MOSFET ratings.
| January 2012 |
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Overvoltage Regulator with 250V Surge Protection
The LT4363 surge stopper protects loads from high voltage transients. It regulates the output during an overvoltage event, such as load dump in vehicles, by controlling the gate of an external N-channel MOSFET. The output is limited to a safe value allowing the loads to continue functioning. The LT4363 also monitors the voltage drop between the SNS and OUT pins to protect against overcurrent faults. An internal amplifier limits the voltage across the current sense resistor to 50mV. In either fault condition, a timer is started inversely proportional to MOSFET stress. Before the timer expires, the FLT pin pulls low to warn of an impending power down. If the condition persists, the MOSFET is turned off. The LT4363-1 remains off until reset whereas the LT4363-2 restarts after a cool down period.
| January 2012 |
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VFD (Vacuum Fluorescent Display) Flyback Power Supply
The LT3758 is a wide input range, current mode, DC/DC controller which is capable of generating either positive or negative output voltages. It can be configured as either a boost, flyback, SEPIC or inverting converter. The LT3758 drives 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.
| January 2012 |