Electronic Design


Dual-Loop Laser-Diode Driver Maximizes Laser Performance
The ADN2840 2.5-Gbit/s dual-loop laser-diode driver enables fiber-optic manufacturers to minimize time-to-market and maximize laser performance. It offers dual-loop control of laser-diode average power and extinction ratio.

This design optimizes laser performance by continuously monitoring the optical output power. It corrects for variations caused by changes in operating temperature and laser-diode degradation over time. Features include an 80-mA maximum modulation current, a 100-mA maximum bias current, and an 80-ps typical rise time. The driver includes user-programmable fail and degrade alarms and enables separate monitoring of bias, modulation, and photodiode currents. The ADN2840 also allows users to perform low-frequency amplitude modulation of the eye for supervisory data channels. Dual-monitor photodiode inputs are included for lambda locking.

The ADN2840 comes packaged in a 48-pin TQFP. In 1000-unit quantities, it costs $24.

Analog Devices Inc., Ray Stata Technology Center, 804 Woburn St., Wilmington, MA 01887; (800) ANALOG-D; www.analog.com.

Line Of NiMH Rechargeable Batteries Includes Lifetime Guarantee
A line of nickel-metal hydride (NiMH) rechargeable batteries are available in AAA, AA, C, D, and 9-V sizes. They are designed to enhance the performance of high-drain, high-use devices, including digital cameras, CD players, and handheld computers.

According to the company, these batteries offer up to twice the run time of conventional NiCd rechargeable batteries. One of the company's AA cells will replace 180 alkaline cells in a headset stereo and 365 alkaline AA cells in a portable CD player. As an environmentally preferred technology, no cadmium is used in the devices. The company offers a AA charger that plugs directly into a wall outlet and charges two to four AA batteries at a time. A universal charger fully charges AAA, AA, C, D, or 9-V NiMH batteries in five hours.

The company offers a lifetime re-placement guarantee. For pricing and availability information, contact the company.

Millennium Rechargeable Power Systems, P.O. Box 147114, Gainesville, FL 32614-7114; (877) 661-6302; fax (904) 462-4726; www.millenniumbatteries.com.

Single SCR And Diode Modules Suit Isolated-Packaging Applications
The LS41 single diode module and LS43 single SCR module are designed for use in applications requiring isolated packaging for rectification or phase control. The isolated package allows for easy mounting with other components on a common heatsink.

The LS41 single diode module is rated at 800 to 2400 V and 600 A. The LS43 single SCR module is rated at 800 to 2200 V and 500 A. These devices meet high-current, single configurations. They provide high durability and high reliability in an industry-standard package.

Typically, the LS4 devices cost $130 each.

Powerex Inc., 200 Hillis St., Youngwood, PA 15697-1800; (800) 451-1415; fax (412) 925-4393; www.pwrx.com.

Low-Profile AC-DC Power Supplies Come In Industry-Standard Package
The low-profile SC150 series of ac-dc switching power supplies provides a reliable source of power for computer peripherals, telecommunications, point-of-sale, and test and measurement equipment. The devices come in an 8- by 4.2- by 1.5-in. industry-standard package and facilitate multiple sourcing.

With a 1.5-in. height, the SC150 power supplies easily fit in 1U racking applications. The series meets UL1950, CSA950, and EN60950 regulations. Standard features include overvoltage, short-circuit protection, ac fail signal, and remote inhibit and remote sense on outputs one and two. The devices accept dc inputs from 130 to 360 V.

Available now, the SC150 series power supplies start at $129 each in 100-unit quantities.

Lambda, 3055 Del Sol Blvd., San Diego, CA 92154; (800) LAMBDA-4; Internet: www.lambdapower.com.

Ballast IC Combines Functions For High-Volume, CFL Applications
The IR2156 embeds a ballast half-bridge driver and timing circuits into one IC. It is designed specifically for high-volume, compact fluorescent-lamp (CFL) applications.

The device contains all core ballast and safety functions, including protection from failure-to-strike and filament failure. An external shutdown signal can be used for automatic reset. Also, it shuts the ballast down in a controlled fashion. The built-in safety and operating functions minimize additional circuitry and reduce overall system cost. Pre-heat frequency, dead-heat time, and pre-heat time are programmable with RC networks to accommodate different lamp styles and operating voltages.

The IR2156 comes packaged in a 14-pin DIP or narrow-body SOIC. In 10,000-unit quantities, the device costs $1.60 each.

International Rectifier, 233 Kansas St., El Segundo, CA 90245; (310) 252-7105; www.irf.com.

DC-DC Power Module Offers On-Board Distributed-Power Solution
The PKF4110B dc-dc power module is a 3.3-V module with a 4-A output. It is available in SMD format and provides full output power for an input range of 36 to 75 V. Less than 8.0 mm high, the device delivers 85% efficiency at its rated output.

An MTBF figure of 4.9 million hours is enabled by thick-film technology and a high degree of silicon integration. Board spacing down to 15 mm is provided. The module is optimized for free convection cooling and has an operational ambient-temperature range of −45°C to 100°C. It requires no heatsink to deliver the full 1-W output across the input range. EMC compliance with EN55022 simplifies system-level design. The output voltage is easily adjusted between 2.8 and 3.8 V using a single resistor.

Compatible with aqueous and semi-aqueous cleaning, the module offers fully molded construction. It is available packaged in tubes, Jedec trays, and tape-and-reel. The 20-g weight ensures compatibility with pick-and-place assembly machines and guarantees 0.1-mm coplanarity.

Contact the company for pricing and availability information.

Ericsson Microelectronics, Isafjordgatan 16, Se-164 81 Kista, Sweden; (877) ERICMIC; www.ericsson.com/microelectronics.

Chargers Enable 55% Reduction Of Li-Ion And Li-Polymer Solutions
The bq2400x family of chargers includes a 1.2-A MOSFET pass transistor and a reverse-current blocking Schottky diode with a combined maximum dropout voltage of 0.7 V. Designers are able to build a full battery charger circuit within a 44 mm2 footprint, compared to the 78 mm2 or more of other charger solutions.

These highly integrated battery chargers enable the 55% size reduction of one- and two-cell lithium-ion (Li-ion) and lithium-polymer (Li-polymer) batteries. The devices perform a high-accuracy programmable charge algorithm, including preconditioning for deeply discharged circuits and voltage, temperature, and time monitoring for safety. A safety timer is provided to halt charging if the preconditioning fails to produce the desired result.

The charging algorithm starts automatically after preconditioning and consists of separate current and voltage phases. The device first applies a constant externally set current until the battery reaches a predetermined voltage. A regulated voltage completes the charging cycle. To maintain the optimum voltage, the bq2400x regulates the voltage to better than ±1.2% through a separate sensing input. The device also monitors its own temperature and, through an external thermistor, the battery's temperature. A low-power sleep mode draws only 1 µA when the charger is not being used.

The device meets the USB power specifications. Voltage and user-display options include the bq24001, bq24002, and bq24003 chargers for single-cell 4.1- or 4.2-V batteries. The bq24004, bq24005, and bq24006 versions work for two-cell 8.2- or 8.4-V batteries.

Available in thermally enhanced 20-lead TSSOP PowerPad packages, pricing for the bq2400x family starts at $1.89 each.

Texas Instruments Inc., P.O. Box 954, Santa Clara, CA 91380; (800) 477-8924, ext. 4500; www.ti.com.

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