Wireless Systems Design

On The Wireless Front

Milpitas, California
The new LTC4061-4.4 from Linear Technology Corp. is a compact, standalone, linear 1-cell 4.375-V (4.4-V maximum) Li-Ion battery charger. Its advanced features improve charging safety, simplify charge termination and status reporting, and prolong battery life. For safety, the LTC4061-4.4 is equipped with a thermistor interface for temperature-qualified charging, an adjustable timer as a backup charge termination, and precision float voltage to prevent cell overcharging. To eliminate the risk of overheating while charging at maximum rate, a patented thermal-regulation circuit keeps the LTC4061-4.4's junction temperature at a safe level.

The device's I/O pins report the state-of-charge during trickle, normal, and end-of-charge modes. They also indicate the presence of an AC adapter or faulty battery. The LTC4061-4.4 prolongs battery life by eliminating unnecessary re-charge cycles with its SmartStart feature. The integrated circuit offers four methods for charge termination: user-adjustable current and time, external digital control, or automatic C/10.

The LTC4061-4.4 can charge new 4.375-V float-voltage Li-Ion batteries with ±0.4% accuracy. Because it requires no external sense resistor, metal-oxide semiconductor field-effect transistor (MOSFET), or blocking diode, it simplifies design. In addition, the LTC4061-4.4 includes a soft-start circuit to minimize the in-rush current at the start of a charge cycle. For Universal-Serial-Bus (USB) -powered charging, the logic pin from a USB controller can select the charge current. It thereby eliminates dependence on external discrete components.

After a battery is fully charged, the LTC4061-4.4 enters a standby mode. Because frequent recharge cycles decrease battery capacity and shorten battery life, the SmartStart feature starts recharging the battery only if the battery voltage drops below 4.275 V. This feature reduces unnecessary charge cycles. At any point in the charge cycle, the LTC4061-4.4 can be shut down, limiting battery drain current to less than 2 µA.

The LTC4061-4.4 is housed in a compact 3-3-3-mm DFN package. It is ideal for charging a battery from a wall adapter or Universal Serial Bus in MP3 players, digital cameras, personal digital assistants (PDAs), and cell phones. In quantities of 1000, pricing for the LTC4061EDD-4.4 begins at $2.05 each. For more information, visit the company's web site at www.linear.com.

San Jose, California
The Spartan-3E FPGA family from Xilinx, Inc. is the company's fourth family to utilize 90-nm process technology. Ranging from 100K to 1.6M system gates, the Spartan-3E family claims to deliver the lowest cost per logic cell in the FPGA industry. The family is focused on reducing unit and overall system costs by offering a wide range of platform features at extremely low price points. For example, the Spartan-3E family implements microprocessor, microcontroller, and DSP functions at standard product pricing. It includes the 32-b MicroBlaze embedded processor for an effective cost of $0.48, the 8-b PicoBlaze embedded processor for less than $0.10, and a DSP cost/performance ratio of less than $1/GMAC/s.

Spartan-3E devices also include a host of features tuned for the consumer-electronics market. These built-in platform features reduce the need for other discrete devices, lowering system costs and simplifying design. The Spartan-3E family also lowers system costs by supporting commodity serial (SPI) and byte-wide, parallel Flash memory for configuration along with the Xilinx Platform Flash solution. Because many high-volume systems already include Flash memory with a few megabits of unused capacity, FPGA configuration memory can cost nothing.

Spartan-3E devices are already being delivered to customers including shipments of the Spartan XC3S100E device with 100K system gates for under $2.00. Additional family members will begin shipping in the second quarter of this year.

To learn more, visit www.xilinx.com.

San Jose, California
Altera Corp. has debuted its new DSP Development Kit, Cyclone II Edition. This edition features Altera's low-cost Cyclone II field-programmable gate arrays (FPGAs), Texas Instruments' (TI's) high-performance ADS5500 analog-to-digital converters (ADCs), and an interface to TI's DSP Starter Kits (DSKs). The kit allows engineers to design, prototype, and debug digital-signal-processing (DSP) co-processing applications for wireless infrastructure, medical diagnostic, imaging, and test and measurement equipment.

The DSP Development Kit, Cyclone II Edition provides a comprehensive platform including a development board, the latest version of The MathWorks' Simulink software, and Altera's DSP Builder and Quartus II design software. In addition to the ADS5500 ADC, the development board utilizes a number of other TI devices to meet the power-supply requirements of the Cyclone II device and other on-board components. Among these devices are digital-to-analog converters (DACs), audio codecs, and power-management ICs. The development board has an external-memory-interface (EMIF) connector to interface directly with TI's DSKs, facilitating the development of TI DSP and Cyclone II FPGA-based co-processor designs.

The DSP Development Kit, Cyclone II Edition will ship in the second quarter of this year. It will be priced at $995. More information about this DSP development kit can be found at www.altera.com.

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