LTspice IV: Noise Simulations
with Tyler Hutchison, Applications Engineer

LTspice IV can perform frequency domain noise analysis which takes into account shot, thermal and flicker (1/f) noise. The resulting noise density (in units of volts per square root hertz) can then be plotted to aid in circuit analysis and understanding.

This video covers how to setup a .noise simulation in LTspice to view both input and output referred voltage noise and discusses a couple of tricks to learn more about noise contributors.

I2C Bus/SMBus Buffers & Accelerators - Video Product Brief
with Chris Gobok, Product Marketing Engineer, Mixed Signal Products

I2C bus buffers, multiplexers, accelerators and isolators address a wide variety of issues that commonly arise when many nodes are added to a bus. A bus buffer is commonly used in high availability (Hot Swap) environments to provide level translation or level shifting capabilities for 1V, 1.2V, 1.5V, 1.8V, 2.5V, 3.3V and 5V buses, and break down bus capacitances into smaller compliant pieces. Similarly, Linear Technology’s stand alone or built-in rise time accelerators help speed up signal rise times to help devices meet I2C requirements. Aside from increasing fan-in or fan-out, our software-programmable and pin-selectable I2C multiplexers help resolve I2C address limitations while integrating bus buffers and rise time accelerators for an all-in-one solution.

Only Linear Technology I2C bus buffers and multiplexers with stuck bus protection provide automatic recovery from an I2C bus stuck low. If SDAOUT or SCLOUT is low for 30ms, these devices break the bus connection and automatically generate clock pulses in an attempt to unstick the bus, thereby providing a more reliable system with minimum user intervention. Features such as low offset, high ESD and level translation down to 1V are common within our bus buffer family. In addition, hot swap circuitry allows users to place our bus buffers on the edge of an I/O card, then insert or remove that card from a live backplane without disturbing communications. All of our I2C devices address other digital serial 2-wire buses as well, including SMBus, PMBus, the AdvancedTCA (ATCA) Intelligent Management Platform Management Bus (IPMB), and the HDMI Display Data Channel (DDC) bus.

LT3015 1.5A, Low Noise, Negative LDO with Precision Current Limit - Video Product Brief
with Steve Knoth, Senior Product Marketing Engineer, Power Products

The LT®3015 series are low noise, low dropout, negative linear regulators with fast transient response. The devices supply up to 1.5A of output current at a typical dropout voltage of 310mV. Operating quiescent current is typically 1.1mA and drops to < 1μA in shutdown. Quiescent current is also well controlled in dropout. In addition to fast transient response, the LT3015 series exhibit very low output noise, making them ideal for noise sensitive applications.

The LT3015 regulators are stable with a minimum 10μF output capacitor. Moreover, the regulator can use small ceramic capacitors without the necessary addition of ESR as is common with other regulators. Internal protection circuitry includes reverse output protection, precision current limit with foldback and thermal limit with hysteresis.

The LT3015 regulators are available in fixed output voltages of –2.5V, –3V, –3.3V, –5V, –12V and –15V and as an adjustable device with a –1.22V reference voltage. Packages include the 5-lead TO-220 and DD-Pak, a thermally enhanced 12-lead MSOP and the low profile (0.75 mm) 8-lead 3mm × 3mm DFN.

LTC3375 8-Ch Programmable, Parallelable 1A Buck PMIC - Video Product Brief
with Steve Knoth, Senior Product Marketing Engineer, Power Products

The LTC®3375 is a digitally programmable high efficiency multioutput power supply IC. The DC/DCs consist of eight synchronous buck converters (IOUT up to 1A each) all powered from independent 2.25V to 5.5V input supplies.

DC/DC enables, output voltages, operating modes, and phasing may all be independently programmed over I2C or used in standalone mode via simple I/O with power-up defaults. The DC/DCs may be used independently or in parallel to achieve higher output currents of up to 4A per output with a shared inductor. Alarm levels for high die temperature may also be programmed via I2C with a maskable IRQ output for monitoring DC/DC and system faults.

Pushbutton ON/OFF/RESET control, power-on reset, and a watchdog timer provide flexible and reliable power-up sequencing and system monitoring. The LTC3375 is available in a low profile 48-lead 7mm × 7mm QFN package.

Dust Networks Current Calculator Demo

In the wireless sensor network WSN marketplace, battery life or power consumption is a key differentiating feature. SmartMesh products are uniquely well positioned to win in any battery life comparisons because they use the lowest-power radios and the best protocols to deeply duty cycle those radios. That said, it is a fact that at the moment one installs a device, they do not know what the battery life of that device is going to be. Will it be a leaf node in the mesh, responsible for no routing of any other device's data? Will it be a heavily loaded router? Will the retry rate in the network make it work harder?
What is the cumulative effect of these uncertainties? Does it make battery life drop in half? By 5x? By 100x?

In order to take away some of the uncertainty associated with power consumption and battery life, we've developed the Current Calculator. You can interact with this Excel spreadsheet to get estimates of power consumption and battery life of motes running in networks that you can specify. The Current Calculator is an approximate tool for estimating current consumption and battery life, but it is an excellent tool for doing a sensitivity study and for making relative comparisons. The conclusions drawn here are based upon these relative comparisons. In all of the examples, we're using the default values of a 3.6V supply and a room temperature of 25 degrees Celsius.

Cable Drop Compensator Improves Load Regulation
with Jim Sousae Design Engineer, Signal Conditioning Products

Power distribution systems such as USB are ubiquitous. They can be found in automotive dashboards, home charging systems and office equipment. Cellphones, electric toothbrushes, PC printers and personal computers all use battery chargers.

These systems are designed to be inexpensive. They use the smallest number of wires and thinnest gauge possible and often have connectors that are prone to high resistivity. The IR drops in these wires and connectors reduces the voltage and power available for charging or may drop to the point where charging is impossible.

Existing solutions for this wire drop include Kelvin sensing regulators and LTC’s virtual remote sense chip, the LT®4180. These solutions can be expensive or difficult to incorporate into a design. The LT6110 is compatible with any single or dual wire power cable and is small (SOT23 and 2x2 DFN), inexpensive and easy to implement.

The LT6110 is flexible and allows for good correction in systems where the component values are not well known. For well-understood or stable systems, the correction can be extraordinary, at well under 1% error even with large IR drops.

80V Wide Range I2C Power Monitor Simplifies Challenging System Monitoring Tasks
with Mark Thoren Staff Scientist, Mixed Signal Products

Accurate monitoring of power is an essential part of a reliable and energy efficient (green) system design. Measuring voltage and current of low voltage (1.8V to 36V) supplies is straightforward, but higher voltages present additional challenges.

In this video, we will show the LTC2945 wide range I2C system monitor. This device monitors the current, voltage and power of any 0V to 80V rail, and the rail-to-rail current input allows the sense resistor to be either at the high side or low side of the supply. The LTC2945’s wide operating range is ideal for many applications, including 48V telecom equipment, advanced mezzanine cards (AMC) and blade servers.

The LTC2945 measures current and voltage with a 12-bit Delta Sigma ADC, calculates power, and stores this information, along with minimum and maximum values, in I2C accessible registers. Measurements are accurate to ±0.75% over the entire operating temperature range. If any parameter exceeds the user-programmable limits, the LTC2945 flags an alert register and pin per the SMBus alert response protocol. The 400kHz I2C interface features nine device addresses, a stuck bus reset timer, and a split SDA pin that simplifies opto-isolation.

76V Over-the-Top® Input Op Amp Combines Precision, Versatility and Protection
with Arnold Nordeng Design Engineer, Signal Conditioning Products

With the increased-use of electronics in automotive and industrial applications, the need for robust and highly reliable components is essential to ensure a proper functioning system with low maintenance costs. Automotive applications, for example have hostile environments where electronic components may be exposed to a variety of phenomena including battery reversal, load dump and extreme temperature variations. A new Over-the-Top op amp, the LT®6016 was designed for reliable operation with such environment in mind.

LTC2974 Demonstration Video

The LTC2974 is a quad, digital power-supply monitor, supervisor, sequencer, and margin controller. Supervisory functions include over and under threshold limits for current, voltage and temperature on four output channels as well as OV/UV threshold limits for a single input channel. Programmable fault response allows the power supplies to be disabled with optional retry after a fault has been detected. Serial bus telemetry allows four output voltages, four output currents, four output temperatures, internal die temperature and one input voltage to be monitored. Power supply sequencing, precision point-of-load voltage adjustment and margining are supported with PMBus commands. A programmable watchdog timer monitors microprocessor activity for a stalled condition and resets the micro if necessary. The 1-wire synchronization bus supports power supply sequencing across multiple LTC digital power devices. User programmable parameters can be stored in EEPROM. Voltage/current supervisor, voltage/current monitor and temperature faults can also be logged to EEPROM.

High Efficiency Bidirectional Cell Balancer Maximizes Capacity and Lifetime of Series Connected Battery Stacks
with Mark Vitunic Designer, Power Products

Large, series connected strings of batteries are commonly used in electric vehicles, backup power systems and a wide variety energy storage applications. Maximizing the lifetime and ensuring safe usage of such battery stacks requires accurate measurement and balancing of each cells’ state of charge (SoC). Passive, or dissipative, balancing can correct for SoC mismatch due to temperature gradients or cell to cell impedance differences throughout the pack. However, passive balancing cannot compensate for capacity differences that result from cell aging. Cell aging occurs in all cells and occurs at different rates due to the same factors that cause SoC mismatch. Without capacity compensation, the runtime of the battery is limited by the lowest capacity cell in the stack.

Active balancers such as the LTC3300 have the ability to correct for SoC imbalance as well as compensate for cell to cell capacity differences. By efficiently redistributing charge from mismatched cells, the LTC3300 maximizes the useable capacity of the battery stack. The LTC3300 provides high current, high efficiency bi-directional cell balancing for series connected batteries. Each IC can simultaneously charge or discharge up to 6 series cells. There is no limit to the height of the stack. Balancer to balancer communication is achieved through a high noise margin SPI bus, and numerous safety features ensure reliable, efficient, high current active balancing.