Tag Archives: LDO

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]

Power supply IC generates low-noise bipolar (+/-) power rails


by Graham Prophet @ edn-europe.com:

LTC3265 is a high voltage, highly integrated, low noise dual output power supply IC which takes a single positive input supply (VIN_P) and generates low noise bipolar rails up to ±2•VIN_P without any inductors. High voltage boost and inverting charge pumps deliver low noise dual outputs with post-regulating ±50 mA LDOs

The device includes a boost doubling charge pump, an inverting charge pump and two low dropout (LDO) regulators. The boost charge pump has a 4.5V to 16V input range and powers the positive LDO post regulator from its output, VOUT+. The inverting charge pump has a wider input range (4.5V to 32V) which may be connected to either the boost input or output. The negative LDO post regulator is powered from the output of the inverting charge pump, VOUT-. The LTC3265 is suited for a variety of applications that require low noise bipolar supplies from a high voltage input, such as industrial/instrumentation low noise bias generators, portable medical equipment and automotive infotainment systems.

Power supply IC generates low-noise bipolar (+/-) power rails – [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]

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]

Dynamic Voltage Scaling with a Dual LDO


This application details how a dual-channel LDO may be used to provide a dynamic voltage scaling output. This function is useful when powering microcontrollers that have a wide operating voltage range: it is advantageous to lower the operating voltage of the MCU in order to achieve lower power consumption (when possible).

The MSP430G2001, for example, has a supply voltage range that varies depending on the system frequency and programming modes. As an example, when the system frequency is 1MHz and flash memory programming is not required, the supply voltage range spans from 1.8V to 3.6V. However, if flash memory programming is required, the supply voltage range contracts to 2.2V to 3.6V.

Dynamic Voltage Scaling with a Dual LDO – [Link]

Smartphone Quick-Jack


The Smartphone Quick-Jack Solution repurposes the standard 3.5mm stereo audio jack found on most smartphones into a self-powered data channel that makes communication with these smartphones as easy as plugging a headset jack into the audio port. The hardware/software platform is designed for iPhone® and Android® smartphones. This project will make it easy to connect external devices into a phone. It gives smartphones application developers an easy way to add context-aware application features, input user and environment data, or connecting peripherals. And also provides end-product designers instant access to smartphones’ convenience, appealing user interface, and cloud connectivity.

This project is compatible with both Open Mobile Terminal Platform (OMTP) and American Headset Jack (AHJ) standards; the hardware identifies the type of headset automatically and configures the hardware accordingly. First, a comparator circuit detects the type of headset port Quick-Jack has been inserted into. The result is interpreted by the LPC800, which then configures an analog switch accordingly. The analog switch connects the right pin of the jack plug to the right signal on the circuit board (GND/MIC). Continue reading Smartphone Quick-Jack

A development board for the ESP8266-03


Limpkin has build a development board for the ESP8266-03:

The ESP8266 modules come with a pre-loaded firmware that will accept some commands through their UART interface (connect to wifi, open udp socket, send data to this IP…). Moreover, since Espressif recently released their SDK you can now load your own custom programs using the existing bootloader. To launch this bootloader you just have to connect some IOs to GND in a specific order.
However, anyone wanting to develop a project involving dozens of Wifi nodes has to start from somewhere, eg make a prototype of their future platform. That is why I developed this development board, so the prototyping stage is as simple as possible.
As you can see in the picture below the dev board breaks out all the ESP8266-03 IOs, includes a 3.3V LDO, a USB to UART converter, some logic and a button to automatically start the bootloader.

A development board for the ESP8266-03 – [Link]

Maxim Fremont: 16-Bit, High-Accuracy, 0 to 100mV Input, Isolated Analog Front-End (AFE)


This compact Fremont subsystem reference design accurately measures low voltage, 0 to 100mV, single-ended analog signals with a high-accuracy, 16-bit analog front end (AFE) complete with an isolated data path. The design optimizes the functions of an ultra-precision low-noise buffer (MAX9632); a highly accurate ADC(MAX11100); an ultra-high-precision 4.096V voltage reference (MAX6126); a 600VRMS monolithic data isolator (MAX14850); and low-dropout (LDO) regulators providing regulated +6V, +5V, and -5V power rails (MAX1659 and MAX1735).This one-of-a-kind AFE solution works in many applications requiring low-voltage input, high impedance, and high-accuracy analog-to-digital conversion.

Maxim Fremont: 16-Bit, High-Accuracy, 0 to 100mV Input, Isolated Analog Front-End (AFE) – [Link]

Ultra-Low-Noise LDO


Of the many low-dropout (LDO) regulators used to regulate voltage in electronic systems, some are specifically designed for low-noise operation. The MAX8887 low-noise LDO, for example, achieves a noise voltage of only 42µVRMS over the 10Hz to 100kHz range. Applications such as the ultra-low-noise oscillators required in instrumentation, however, require even lower noise. To fulfill that requirement, this project features the MAX6126 and a combination of low-noise components and filtering that achieves an output noise of only 6nV/√Hz at 1kHz

Ultra-Low-Noise LDO – [Link]