Linear Launches Current Monitor For 4-80V Systems

Linear Technology has introduced the LT2940, a power and current monitor for 4 to 80V systems. The LT2940 provides the necessary circuits to accurately measure, monitor and control power in situations where both the current and voltage may vary due to supply-voltage uncertainty, component parametric changes, transient conditions or time-varying signals.

It uses a true four-quadrant analogue multiplier that results in five per cent power-measurement accuracy and three per cent current-measurement accuracy, ensuring that boards and systems achieve optimum power efficiency and reliability. The LT2940 is suitable for use in line cards and servers, power-sense circuit breakers, power-control loops and a variety of metering applications. It measures a high-side current and differential voltage, and calculates the instantaneous power at a bandwidth exceeding 500kHz.

Bidirectional high-side currents and bipolar voltage differences are correctly handled by a four-quadrant multiplier and push-pull output stage, which allow the device to indicate forward and reverse power flow. After current and voltage measurements are taken, current and power levels can be scaled, filtered and monitored separately via their respective proportional-to-current and proportional-to-power current outputs.

Meanwhile, an integrated comparator with complementary open-collector outputs can be used to create PWM control loops, or provide simple logic of, for example, an over-power pin, an LED indicator alarm, a MOSFET load-cutoff switch, an external fan, or a binary counter for metering applications. The LT2940 is offered in commercial and industrial versions, supporting operating temperature ranges from 0 to 70C and -40 to 85C, respectively. It is available in RoHS-compliant, 12-pin 3 x 3mm DFN and 12-lead MSOP packages.

Linear Introduces LTC2635 Rail-To-Rail DACs

Linear Technology's LTC2635 quad 12, 10 and 8bit rail-to-rail digital-to-analogue converters (DACs) integrate a precision 10ppm/C reference in 3 x 3mm QFN and MSOP packages. Ordering options include 2.5V (LTC2635-L) and 4.096V (LTC2635-H) DAC full-scale outputs. The LTC2635-L offers power-on reset to zero and mid-scale options. It also includes ordering options for high impedance outputs at power-on reset and during shutdown.

This allows the DAC to be used in applications such as power-supply margining where the DAC outputs must be electrically isolated from the power supply at power-on, before being called to action to adjust supply voltages up and down. The LTC2635's small size and internal reference are important for a variety of industrial, automotive and ATE applications. The LTC2635 offers 12-bit performance of +/-2.5LSB (max) INL error and 3nVs crosstalk, ensuring that a voltage change on one DAC has minimal effect on the other DACs.

Operating from a single 2.7 to 5.5V supply, supply current is a low 125uA per DAC. In addition to selecting one of three resolution options, designers can also choose between a 2.5 or 4.096V full-scale range, as well as power-up options for zero-scale, mid-scale or Hi-Z. The 16-pin 3 x 3mm QFN package includes a hardware load-DAC (LDAC) pin, three address pins for selecting 27 unique I2C addresses and a Reflo pin.

The 10-pin MSOP package has just one address pin for selection of up to three unique addresses on the I2C bus. All LTC2635 options are guaranteed over the automotive (-40C to +125C) and commercial (0C to +70C) temperature ranges. Pricing begins at USD2.03 (GBP1.31) each in 1,000-piece quantities.

Linear Launches 1A DC/DC Regulator System

Linear Technology has introduced a complete 1A DC/DC regulator system in a package. The LTM8031 is the second member of the company's electromagnetic-compatible (EMC) DC/DC Umodule range. The system includes an inductor, a switching DC/DC controller, power switches, filters and all support components housed in a 9 x 15 x 2.82mm land-grid-array (LGA) package.

The LTM8031 has been tested by an independent electromagnetic-interference (EMI) laboratory and is compliant with the radiated-emissions requirements of EN55022 Class B. The switching frequency can be adjusted from 200kHz to 2.4MHz with a resistor or synchronised to an external clock. The device operates from a wide input voltage range of 3.6V to 36V and regulates an output voltage from 0.8V to 10V at up to 1A.

Applications for the LTM8031 include converting and regulating automotive battery voltage, distributed power supply and high-voltage industrial and avionics systems. The LTM8031 weighs 1.2g and is offered in industrial and military temperature-grade specifications. For a higher output current up to 2A, the LTM8032 is available with identical layout and pin functions.

To improve efficiency at light loads, the device automatically activates Burst Mode operation, which keeps the output capacitor charged to the proper voltage with single cycle bursts of current followed by sleep periods, minimising input quiescent current. The LTM8031 is priced at USD9.95 (GBP6.28) in 1,000-piece quantities.

Hepcomotion Unveils Linear Motion Actuators

Hepcomotion has developed a range of actuators for linear motions systems so that each axis operates optimally and contributes to the overall efficiency and longevity of the system. The Hepcomotion light- and medium-duty X-Y-Z systems are suitable for industrial and scientific applications such as pick and place, automated assembly, inspection and product labelling.

The X-axis foundation of the system is the PDU2 linear actuator, which features Hepcomotion's Herculane wheel technology in a compact belt-driven unit. The Y-axis requires a particularly high load capacity and stiffness against twisting loads. The PDU2M shares the same technology and format as the PDU2 but with moment load capacity improved by 200 per cent and stiffness by 1,000 per cent. The needs of the Z-axis are different again, with enhanced linear force and higher gearing required.

The PSD80 linear actuator is suitable for this duty, with drive from a super-smooth stainless-steel lead screw operating with a bearing polymer nut. It also uses Herculane wheel technology in a unit that is suitably matched to the other axes in terms of performance, size and cost. All units fit together using standard components to create multi-axis systems that are claimed to perform better than similar units where 'general-purpose' actuators are used for all axes. Lightweight aluminium T-slotted profiles allow the axes to be incorporated into frames, such as the Hepcomotion MCS aluminium frame and Machine Construction System, or more complex machines.

Hepcomotion supplies its X-Y-Z systems as individual parts, in kit form, or fully assembled multi-axis units. This type of X-Y-Z configuration will perform for systems with a working envelope of just a few centimetres right up to those with dimensions of several metres. Motors, drives, cables, electrical connectors and a turnkey service can be provided on application.

Sherborne Launches A545 Linear Accelerometers

Sherborne Sensors has introduced the A545 range of single, biaxial and triaxial solid-state linear accelerometers, designed to measure acceleration and deceleration in harsh environments. Available in ranges from +/-2G to +/-500G, A545 series accelerometers feature an advanced MEMS sensor, incorporating air damping.

Unlike fluid-damped devices, air damping is essentially independent of temperature, which enables the transducer to perform over a wide temperature range. Sensors are fully compensated for temperature effects on both sensitivity and zero, and incorporate positive mechanical stops. Housed within a lightweight (less than 40g), durable light alloy package with solder pin connectors, the A545 series provides shock resistance and over-ranging protection.

The A545 series is designed to operate from an unregulated DC power source and have useable frequency responses from DC to several kHz. Typical applications for the A545 series include data acquisition systems, crash testing, fatigue life monitoring and prediction, low-frequency vibration analysis and structural surveying. Custom designed units can also be manufactured and tested to conform to specific requirements.

All A545 series accelerometers are 100 per cent tested and calibrated at the factory prior to shipment, and are accompanied by a two-year warranty. A545 accelerometers are also part of the Sherborne Sensors 'guaranteed on-time delivery' programme. The A545 series accelerometers are ISO9001: 2000 certified and are backed by applications engineering support, global technical sales presence, repair, refurbishment and calibration services.

LT3070 Linear Regulator Has Low Dropout Voltage

The LT3070 is a digitally programmable Linear regulator said to have the lowest dropout voltage, lowest noise and fastest transient response of any monolithic 5A LDO currently available. Dropout voltage at 5A is 85mV and output voltage noise at 5A is 25uVRMS over a 10 to 100kHz bandwidth. The LT3070's 1MHz unity-gain bandwidth, coupled with its minimum 15uF ceramic output capacitance, provides 30mV of overshoot/undershoot in response to a 4.5A output load step, saving bulk capacitance, space and cost.

It is suitable for efficiently powering low-voltage, high-current devices such as FPGAs, DSPs, ASICs, microprocessors, sensitive communication supplies, server/storage devices and post-buck regulation applications. The LT3070's output voltage is digitally programmable from 0.8 to 1.8V in 50mV increments. Accuracy is tightly specified at +/-1 per cent over line, load and temperature. A digital margining feature can adjust system output voltage in increments of +/-1, +/-3 or +/-5 per cent, said to be advantageous during a system development debug.

A Powergood flag indicates if output voltage is in regulation or the device is in UVLO and the flag also provides an early warning indication of a thermal fault. The LT3070's input supply-voltage range is 0.95 to 3.0V and its bias supply voltage ranges from 2.2 to 3.6V. The bias supply provides gate drive to the internal NMOS pass device. Multiple LT3070 devices can be easily paralleled for higher output current and to spread heat across a PCB.

A tracking feature can control a buck regulator powering the LT3070's input. This tracking function drives the upstream buck regulator to maintain the LT3070's input voltage at VOUT + 300mV, minimising power dissipation. If output voltage is dynamically changed, the tracking function automatically adjusts the output voltage of the buck regulator to maintain efficiency. Internal protection circuitry includes UVLO, reverse-current protection, precision current limiting with power foldback and thermal shutdown with hysteresis. The LT3070 is offered in a thermally enhanced, low-profile (0.75mm) 28-lead 4 x 5mm QFN package and both E and I grades operate from -40 to 125C junction temperature range.

Linear Receiver Subsystem Reduces Board Space

Linear Technology has introduced the LTM9003 wideband RF-to-digital receiver subsystem. The system includes a high-performance 12-bit, 250Msps analogue-to-digital converter (ADC), a bandpass filter, intermediate frequency (IF) amplifier and a high linearity RF downconverting mixer. The integrated Umodule receiver reduces board space and development time for wireless basestations implementing PA linearization with digital predistortion (DPD). The LTM9003 harnesses years of signal chain design experience and offers it in an 11.25mm x 15mm Umodule package.

DPD addresses the most significant source of power consumption in a basestation: the PA. Powerful digital algorithms correct nonlinearity in the power amplifier, allowing it to operate at a higher average power level without generating excessive distortion. A single 20W PA without DPD may run at less than 10 per cent efficiency, meaning greater than 200W of power consumption. Due to the number of power amplifiers in a basestation, the savings are significant to the operating expense (OPEX) of the service provider.

Digitising the fifth or even seventh order harmonics requires a very wide bandwidth, low noise receiver with an exceptionally flat passband. The LTM9003 includes a 125MHz bandpass filter that exhibits less than 0.5dB passband ripple across the entire band. The noise floor of the receiver chain from the RF input to the LVDS digital output is just -147.3dBm/Hz, which is well below that of the PA. Since DPD is a feedback loop, the receiver (also called a transmit observation path receiver) benefits from low latency; a faster loop leads to better efficiency in the PA and therefore even lower power consumption.

The ADC in the LTM9003 has just five clock cycles of latency and the absolute delay through the filter is just 2.7ns. The LTM9003 is packaged in a space-saving LGA package, utilising a multi-layer substrate that shields sensitive analogue lines from the digital traces to minimise digital feedback. Supply and reference bypass capacitance is placed inside the Umodule, tightly coupled to the die, providing a space, cost and performance advantage over traditional packaging. With no external capacitance required, the LTM9003 consumes approximately one-fourth the space of discrete implementations.

Rosa Surface Grinder Has Linear Motor Drives

NL Machine Tool Consulting has announced that Rosa Ermando has introduced the linear motor drive for the table of its grinding machines, series Steel Linear and R46. The linear motor is said to reach high speeds and accelerations, where during grinding a traverse speed of approximately 65m/min and accelerations of 2G are feasible. This increases the output capacity and/or reduction of machining times. It also generates high forces, where the thrust of the motor easily reaches up to 10,000N.

The linear motor has no mechanical components with power transmission components and avoids many disadvantages such as friction, mechanical backlash, and mechanical resonance due to elasticity. It is also said to be precise as it is controlled by a linear optical scale, which means positioning of table within micron precision is possible. The linear motor drive is claimed to be a flexible solution that allows creep-feed grinding, with slow table motion, interpolation between table and vertical axis, high-speed grinding till 65m/m. The machines are controlled through a Siemens Sinumerik 840 DiE CNC control unit and can be supplied with fourth and fifth axis for complicated components.

OEMDynamics Enhances Linear Belt Drive

OEMDynamics, a division of Animatics, has announced enhanced features on the HLD 60-H3 actuator. Due to its harmonic principle, the H3 belt achieves a gear reduction equivalent of up to 40:1 without the need for a gearhead, which means it takes up less space and weighs less.

The HLD60-H3 can achieve lengths greater than 3m without attributable losses in performance and can therefore be used in a wide range of applications. The actuator features a sturdy and seamless magnetically retained seal strip and meets European Machinery Directive 2006/42/EC.

Micromech Offers Complete Linear Motion Solution

Micromech's Promech linear actuators from Parker are for OEM instrument manufacturers looking to speed time to market and reduce the overall installed cost for linear motion axes. Promech Series LP28 and LD28 actuators come completely assembled and tested and include linear bearings, drive screw, thrust bearings, motor mount, coupling and motor. With a travel range from 5mm to 500mm, the LP28 has several linear bearing options and a variety of leadscrew and motor size options to match the positioner to the application requirements.

This compact actuator is suitable for positioning payloads up to 4.5kg and may also be fitted with optional seal strip, home and limit sensors. The LD28 is a complete linear actuator solution that offers greater screw and motor design flexibility, enabling OEMs to pursue optimal solutions for their applications. It offers a travel range from 5mm to 300mm and is offered with a variety of options to match the actuator to application requirements.

The LD28 is also suitable for thrusting applications requiring up to 4.5kg of thrust. The LP28 has a miniature cross section of 28mm x 28mm, is designed with an optimal length-to-travel ratio, has a high-performance leadscrew drive train and re-circulating linear bearing. Some competitive miniaturised drive trains use the radial bearings in the step motor to contain the motor rotor, manage thermal expansion as the motor heats, and bear the axial loads generated by the application.

In some cases this is an acceptable practice, but may prove to be a reliability risk further down the road. The LP28's bearing design results in a highly reliable and long life positioner, said Micromech. The leadscrew options are 1mm, 3mm and 10mm, and NEMA 11 or NEMA 17 stepper motors are included as standard. Fully adjustable home and limit sensors are available and the actuators can be configured for multi-axis platforms. The design has an extruded aluminium body that provides functionality and structural strength.

Internally, the drive train is highly integrated and includes the drive screw, screw nut, independent pre-loaded thrust bearing set, shaft coupling and motor. Externally, an optional linear bearing may be used to support heavier or cantilevered payloads. Installation is performed using toe clamp mounting. Home and limit sensors, which are triggered by a magnet in the carriage assembly, may be mounted using the T-slot and are fully adjustable over travel. The LP28 is engineered for transport of small payloads over distances as short as 5mm and as long as 500mm.

The LP28 is commonly used in life sciences, medical and semiconductor equipment although it is not limited to these markets. Typical applications include transport of 0.45kg to 0.9kg payloads such as microplates, vials and small syringe pumps. In inspection applications, the LP28 can be used as a focus axis for adjusting the position of a camera, optics or payload. The LP28's light weight also makes it suitable for mobile equipment. It is available with multiple lead options to match payloads over the life of the actuator.

The LD28 is also a miniature cross section actuator 28mm x 28mm and has an independent thrust bearing set resulting in a high thrust per package size. It can have either stepper (NEMA 11 or NEMA 17) or servomotor; it has backlash compensation and a high-performance leadscrew drive train with options of 1mm, 3mm and 10mm leadscrew. Designed for OEMs needing simple positioning solutions for instrument and light industrial applications, the Promech range of positioners offers a complete positioning solution.

The LD28 is also a packaged linear actuator having all the same 'completeness' attributes as the LP28 being fully assembled and tested. The Promech LD28 is engineered for thrusting small payloads over distances as short as 5mm and as long as 300mm. In addition to the standard configurations, the LD28 actuators can be customised to address the unique requirements of a particular high-volume application. These modifications may further reduce the installed cost and can include special motors (stepper, servo or DC), motors fitted with rotary encoders, special screws (finer leads, ballscrews, special nuts), and environmental preparation (vacuum, high temperature).

Here again the LD28 is commonly used in life sciences, medical and semiconductor equipment, although it is not limited to these markets. Typical applications include syringe pumps and positioning stages and its light weight makes it suitable for mobile equipment.

Linear Unveils H-Grade DC/DC Controller

Linear Technology has announced the H-grade version of the LTC3824, a 4V to 60V input range, low quiescent current step-down DC/DC controller in a small thermally enhanced MSOP-10 package. This H-grade device is guaranteed up to a 150C operating junction temperature range and is suitable for automotive and industrial applications subjected to high ambient temperatures, demanding a small solution size for output voltages ranging from 0.8V to Vin at up to 5A.

The device's 4V minimum input voltage supports automotive cold crank and the 60V maximum input voltage survives inductive load dumps without the need for external clamping circuits. The LTC3824H can be configured for Burst Mode operation, which reduces the controller's no-load current draw to only 40uA and safely powers pre-biased loads. The shutdown current is 7uA. With 100 per cent duty cycle capability, the LTC3824H has a very low dropout voltage, allowing Vout to approach Vin, a feature that extends the run time in battery-powered applications.

In addition, the LTC3824H can be programmed to a fixed frequency from 100kHz to 600kHz. For noise-sensitive applications, the device can be synchronised to an external clock over the same range. Its onboard Mosfet gate driver powers an external P-channel Mosfet to produce greater than 90 per cent conversion efficiency. The LTC3824H's current mode architecture provides fast line and load transient response as well as cycle-by-cycle over-current protection. Additional features include programmable current limit and soft-start, along with over-voltage protection. The LTC3824H operates and is guaranteed over an operating junction temperature range of -40C to 150C.

Linear Offers LTC3569 Synchronous Buck Regulator

Linear Technology's LTC3569 is a triple-channel, high efficiency 3MHz synchronous buck regulator. It delivers 1.2A of continuous output current from one channel and 600mA from each of the other two channels. Using a constant frequency current-mode architecture, the LTC3569 operates from an input voltage range of 2.5 to 5.5V, making it ideal for single-cell Li-Ion/polymer or multicell alkaline/NiCad/NiMH applications.

Each of the three output-voltages are independently programmable by lowering the feedback voltage of each channel from 800 to 425mV (in 25mV increments) by toggling the EN pin, enabling dynamic adjustment of each channel's output voltage. Additionally, each of the 600mA regulators can act as slave power stages to each other or to the 1.2A channel to support higher currents, providing additional design flexibility.

The LTC3569's switching frequency can be programmed between 1 and 3MHz or set at 2.25MHz, enabling the designer to optimise efficiency while avoiding critical noise-sensitive frequency bands. The combination of its 3 x 3mm QFN-20 (or TSSOP- 16E) package and high switching-frequency keeps external inductors and capacitors small, providing a compact and thermally efficient footprint.

The LTC3569's internal synchronous switches offer efficiencies as high as 95 per cent, while burst mode operation minimises quiescent current to 100uA (all three channels) in no-load conditions. For applications demanding the lowest possible noise, the LTC3569 can run in a pulse skipping mode to minimise output ripple.

The LTC3569 offers a power-good indicator and is synchronisable to an external clock (1.2 to 3MHz). Other features include internal compensation, over-temperature and short-circuit protection. The LTC3569EUD is available in a 3 x 3mm QFN-20 package and the LTC3569EFE is offered in a 16-lead thermally enhanced TSSOP package. Industrial grade versions, the LTC3569IUD and LTC3569IFE, are tested and guaranteed to operate to the -40C to +85C operating junction temperature.

PDU2M Added To Belt-Driven Linear Motion System

Hepcomotion has introduced the PDU2M to its Profile Driven Unit (PDU2) belt-driven linear motion system. The company said the PDU2M delivers a 200 per cent increase in moment load capacity and 1000 per cent uplift in moment load stiffness compared to a standard PDU2. Direct load capacity is also 50 per cent greater. In practice this means, for example, that designers can use a single PDU2M unit as a horizontal axis in an X-Z system, where previously two PDU2 units working in parallel would have been required to provide the necessary rigidity and strength.

Key to this capability is the high-performance Hepcomotion Herculane wheels that are mounted on adjustable eccentric studs. These wheels run virtually friction-free on the inside of the profile, providing stable support for the carriage plate. Felt wipers sweep debris from their path. The unit is available with a number of carriage designs to allow the quick and easy construction of multi-axis systems with a minimal requirement for brackets and other hardware.

In common with its forerunner, PDU2M comprises a rigid but lightweight aluminium slotted profile into which fits the toothed belt drive and carriage, an arrangement that effectively encloses the unit. It is rated for operating at speeds of up to 6m/s and available with a choice of motors providing driving forces up to 280N. The options include a Smart Drive Taranis stepper-motor drive and control package for multi-axis applications.

Left, right or double drive shafts can be specified together with a range of options such as brakes, positioning encoders and mechanical or inductive limit switches. End-of-stroke protection is provided as standard at both ends by internal buffers. PDU2M is fully compatible with the company's MCS aluminium machine-construction system and is expected to find its niche as a replacement for failing ball-based systems.

Jena Tec Expands Linear And Rotary Motion Ranges

Jena Tec has announced two further models to its linear and rotary motion ranges in the field of precision rotary tables. The first model, the MRT230, is a lightweight ring grinding unit driven by a pancake segmented motor via a gearbox and toothed belt. The cast alloy base plate allows bolting directly to a grinding machine table. Mounted on the rotary axes employing ABEC 7 angular contact bearings is a magnetic chuck, 230mm diameter providing load capability of up to 30kg.

The central 40mm location spigot allows location of fixturing and the unit can be supplied with a variety of three jaw chucks and t-slotted face plates on request. The unit is supplied complete with an electrical control box providing infinitely variable speed control up to 120rpm. The MRT230 is suitable for rotary grinding of bearing spacers and other applications where constant surface finish is important combined with accurate parallelism.

The second product is the ABRT series air bearing rotary table. This range provides an accurate rotational motion in either manual or CNC mode with minimal effort through the provision of an air bearing cushion. The hydraulic clamping mechanism allows rigid clamping for heavy-duty machining. With table diameters from 500mm to 2,000mm and table loading up to 10,000kg with repeatability of +/-0.2 arcsecs, the range is suitable for a variety of applications in boring, milling, grinding and inspection.

The ABRT series can be provided with a torque motor option, encoder feedback and digital readout and can be fully integrated within a CNC control. Jena also offers an industrialised PC-based CNC control allowing retrofitting to existing manual machine tools. Customised designs of ABRT rotary axes can be provided on request relating to higher loading, diameter, acceleration and tolerances.

Linear Guide Systems Are Easy To Specify

Design is capable of carrying heavy loads at high capacity, velocity and acceleration while still excelling in wear resistance. PBC Linear has a new line of cost-effective easy-to-specify linear guide systems. Integral V Technology systems feature a patent pending process that allows for tighter tolerances without additional cost. The design itself is capable of carrying heavy loads at high capacity, velocity and acceleration while still excelling in wear resistance.

IV-T also has a growing number of configurations and a wide range of uses with custom orders available. This versatile product is yet another in a long line of innovative products in PBC's history. With the 20 different configurations already available - and more being developed each week - the IV technology is truly versatile in its application. Products in IV technology include snap-in, bolt-on, integrated and compact configurations. All of which allow for easy installation, and what really sets this product and company apart from others is that Pacific Bearing is willing to work with companies to integrate the IV-technology into their extrusions.

PBC's engineering team is fully prepared to adapt or modify the customer's base design with the new Integral V technology to ensure a successful product. The hardened steel V-raceway allows for a high load capacity, rigidity and wear resistance. The rail is constructed of lightweight aluminium partnered with hardened steel V raceways that are mechanically inserted to create high contact loads and wear resistance; thereby lowering production and replacement costs.