Tag Archives: regulator

LT3091 – –36V, 1.5A Negative Linear Regulator with Programmable Current Limit


The LT®3091 is a 1.5A, low dropout negative linear regulator that is easily paralleled to increase output current or spread heat on surface mounted boards. Designed with a precision current reference followed by a high performance rail-to-rail voltage buffer, this regulator finds use in applications requiring precision output, high current with no heat sink, output adjustability to zero and low dropout voltage. The device can also be configured as a 3-terminal floating regulator.

LT3091 – –36V, 1.5A Negative Linear Regulator with Programmable Current Limit – [Link]


MC34VR500V1ES Multi-Output DC/DC Regulator

The circuit in this reference design features the capability of MC34VR500V1ES to supply multiple DC voltage outputs. This device is designed to support the LS1/T1 family of communication processors, which require efficient and precise level of voltage supplies. With its four switching and five linear regulators, the MC34VR500V1ES can supply power to the whole system, e.g., the processor, memory, system peripherals.

The MC34VR500V1ES device runs with a supply voltage ranging from 2.8V to 4.5V. It can provide nine outputs. Four of these outputs (SW1-4) are buck regulators while the rest (LDO1-5) are general purpose LDOs. Each one of the buck regulator is capable of operating in Pulse Frequency Modulation (PFM), Auto Pulse Skip (APS), and Pulse Width Modulation (PWM) switching modes. These buck regulators also have a current limit feature that generates a fault interrupt whenever there is an overcurrent condition. The SW1 output is capable of providing 0.625-1.875V/4.5A supply while SW2 and SW3 can provide 0.625-1.975V/2A and 0.625-1.975V/2.5A, respectively. The SW1, SW2 and SW3 voltages can be varied with a step size of 25mV. The SW4 output is half of the voltage output of SW3. The general output LDOs can output voltages ranging from 1.8-3.3V with a step size of 100mV except for LDO1 which can only give 0.8-1.55V output with 50mV step size. The LDO1 output can provide current up to 250mA, while LDO2 and LDO4 can output up to 100mA only. The LDO5 output can provide 200mA of current while LDO3 can output up to 350mA. Aside from these nine outputs, the MC34VR500V1ES also have a REFOUT output dedicated for DDR memory reference voltage. The voltage of this REFOUT output is usually half of the SW3 output and can only provide up to 10mA of current. The MC34VR500V1ES outputs can be changed by programming it via the I2C interface.

The operation of the MC34VR500V1ES can be reduced to four states, or modes: ON, OFF, Sleep, and Standby. For the device to turn ON, the input voltage must surpass a voltage threshold of 3.1V, the EN pin must be high, and PORB is de-asserted. The 34VR500 enters the OFF mode when the EN pin is low or there is a thermal shutdown event that forces the device into the OFF mode. Standby mode is usually entered when the STBY pin is asserted for low-power mode of operation. The device only goes into sleep mode if the EN pin is de-asserted. To exit sleep mode, assert the EN pin.

MC34VR500V1ES Multi-Output DC/DC Regulator – [Link]

100V, 1A, synchronous step-down regulator: Iq of 7µA


by Graham Prophet @ edn-europe.com:

LT8631 is a 1A, 100V-input-capable synchronous step-down switching regulator. Synchronous rectification delivers efficiency as high as 90% while Burst Mode operation keeps quiescent current under 7µA in no-load standby conditions.

Its 3V to 100V input voltage range suits it for 48V automotive systems, dual battery transportation, industrial and 36V to 72V telecom applications. Its internal high efficiency switches deliver up to 1A of continuous output current to voltages as low as 0.8V. The LT8631’s Burst Mode operation offers ultralow quiescent current, suiting it for applications such as automotive “always-on” systems. The LT8631’s unique design maintains a minimum dropout voltage, enabling it to operate with duty cycles up to 99%. Its resistor-programmable 100 kHz to 1 MHz frequency range and synchronisation capability enable optimisation between efficiency and external component size. The LT8631’s 20-lead TSSOP package with high voltage lead spacing ensures a compact, thermally efficient footprint for high voltage applications.

100V, 1A, synchronous step-down regulator: Iq of 7µA – [Link]

LDO regulator is qualified for automotive designs

Micrel MAQ53

by Susan Nordyk @ edn.com:

Housed in a tiny 2×2-mm, 6-pin DFN package, the MAQ5300 voltage regulator from Micrel boasts a dropout of only 100 mV at 300 mA. The AEC-Q100-qualified part is suitable for space-constrained and high-reliability applications that are subjected to the harsh environments and temperatures commonly encountered in automotive and industrial applications.

The CMOS regulator operates from an input voltage of 2.3 V to 5.5 V, while delivering a guaranteed output current of 300 mA. Fixed output-voltage options include 1.5 V, 1.8 V, 2.5 V, 2.8 V, 2.85 V, 3.0 V, and 3.3 V. Output voltage noise is specified at 120 µV RMS typical. The MAQ5300 also achieves an initial output voltage accuracy of ±2% and ±3% over temperature.

LDO regulator is qualified for automotive designs – [Link]

Use an LM317 as 0 to 3V adjustable regulator


by Vladimir Rentyuk @ edn.com:

Most engineers know that they can use an inexpensive, three-terminal adjustable regulator, such as Fairchild Semiconductor’s LM317, as an adjustable regulator to only some necessary value of voltage, such as 36 or 3V. This value cannot be less than 1.25V without employing other approaches, however. The devices’ inner reference voltage is 1.25V, and their output voltage accordingly cannot be less than this value without potential bias (Reference 1). One way to solve this problem is to use a reference-voltage source based on two diodes (Reference 2).

Use an LM317 as 0 to 3V adjustable regulator – [Link]

A low-cost 0.5A 33V LED driver module with 90+% efficiency

LG-LED-150702-DF-Futuro Low-cost LED driver Design FigA

by Valentin Kulikov @ edn.com

This article describes simple constant current driver module with fast PWM input that can be used for driving medium and high power LEDs. The module uses an integrated constant-current output, DC-DC buck converter with output current configurable from 0.1 to 0.5A. This article outlines the schematic, design guidelines, operation, and performance of the low cost LED driver.

A low-cost 0.5A 33V LED driver module with 90+% efficiency – [Link]

Voltage regulator with backup management


by elektormagazine.com:

Linear Technology has introduced a voltage supply regulator chip that includes an interface to take care of charging, balancing and monitoring external supercaps (or batteries) for system power backup. Its wide 0.1 V to 5.5 V capacitor/battery voltage and 1.8 V to 5.25V system backup voltage ranges make it suitable for a wide range of backup applications using supercapacitors or batteries. A proprietary low noise switching algorithm optimizes efficiency with capacitor/battery voltages that are above, below or equal to the system output voltage.

The LTC3110 can autonomously transition from charge to backup mode or switch modes based on an external command. Pin-selectable Burst Mode operation reduces standby current and improves light-load efficiency, which combined with a 1 μA shutdown current make the LTC3110 ideally suited for backup applications. Additional features include voltage supervisors for charge direction control, end of charge and a general purpose comparator with open-collector output for interfacing with a microcontroller.

Voltage regulator with backup management – [Link]

LT3088 – 800mA Single Resistor Rugged Linear Regulator


by elektormagazine.com:

Most new voltage regulator chips are based on some variant of the digital switch-mode design which offers better efficiency compared with the more traditional linear regulator designs. Linear Technology has bucked the trend by introducing a new three-terminal linear regulator which offers some significant improvements on earlier designs.

The LT3088 has an input range from 1.2 V to 36 V with an extended safe operating area (SOA) compared to existing regulators, making it ideal for high input-to-output voltage and high output current applications where older regulators limit the output. The LT3088 uses a current source reference, allowing a single resistor to set the output voltage from 0 V to 34.5 V (with 1.2 V dropout). This regulator architecture, combined with low millivolt line and load regulation, enables multiple ICs to be paralleled easily for heat spreading and higher output current. The on-chip trimmed 50 µA current reference is ±1% accurate. The regulation, transient response and output noise (27 µVRMS) are independent of output voltage thanks to its voltage follower architecture.

LT3088 – 800mA Single Resistor Rugged Linear Regulator – [Link]

Buck controller allows 48V to 1V direct step-down

Intersil 8117

by Richard Quinnell @ edn.com:

Aiming to simplify design and increase power density in industrial systems, Intersil has developed the ISL8817 synchronous buck controller. The device accepts DC input voltages from 4.5V to 60 V and produces a selectable output voltage between 0.6V and 54V at up to 20A output current. Able to operate over a wide switching frequency (100 kHz to 2 MHz) with a low duty cycle (40 nsec minimum on time), the controller is able to step down from a 48V source to a 1V output in a single stage. This allows industrial applications using a 48V power distribution bus to provide the many voltages that modern CPUs and FPGAs require without the need for an intermediate low-voltage stage. This both increases power density in such systems as well as reducing conversion losses.

Buck controller allows 48V to 1V direct step-down – [Link]

LDO regulator squeezes into wearables

Semtech SC563by Susan Nordyk @ edn.com:

Housed in a tiny 1.6×1.2-mm, 0.6-mm thin package suitable for wearable electronics and other space-constrained battery-operated applications, the SC563 low-dropout regulator from Semtech provides two regulated outputs at up to 300 mA each, while its fixed output voltages eliminate the need for external resistor divider networks. The device’s ultra-small footprint and low dropout voltage of 180 mV enable designers to implement power supplies where small size and high efficiency are paramount.

The SC563 accepts an input supply voltage of 2.3 V to 5.5 V. It has separate input, output, and enable pins for each LDO channel. Using the lowest possible input voltage for each output voltage reduces the power loss for each rail. Quiescent current of just 50 µA for each channel helps extend battery life. The regulator also offers short-circuit, undervoltage lockout, and thermal protection to prevent device failures.

LDO regulator squeezes into wearables – [Link]