Dual regulator typology needed to power modern cell phones
News & Analysis 3/19/2003 Post a comment
The piling on of features to cell phones and PDAs - in addition to taxing battery life - demands multiple voltages and currents. A switching regulator will serve buck and boost functions, but becomes notoriously inefficient when the handheld drops into a low-current sleep mode. LDOs are good for standby voltages, require few external components, but won't supply much current. From the March issue of Planet Analog magazine, an ON Semiconductor engineer reports on a voltage regulator typology that
Architectures and specs help analysis of multi-standard receivers*
News & Analysis 3/12/2003 Post a comment
Our relationship with Kluwer Academic Publishers gives us access to popular texts on analog design. This article - drawn from Xiaopeng Li and Mohammed Ismail's popular textbook on RF-CMOS receiver circuits - focuses on the front-end requirements for multi-standard radios. This chapter looks at the requirements and waveforms GSM, DECT, and WCDMA. Xiaopeng Li is a design chief with Texas Instruments' data converter group; Professor Mohammed Ismail directs the Analog VLSI Laboratory at Ohio State U
The package interconnect selection quandary
News & Analysis 3/11/2003 Post a comment
Wire-bond and flip-chip assembly are the prime methods for packaging integrated circuits. Each process offers advantages in certain types of applications. But with increasing signal speeds and logic advancements in LSI, ASIC and FPGA IP, package interconnection methods are becoming a more critical factor. Understanding the impact of interconnections is becoming a requirement for product stability, says this Zuken engineer in a highly personalized account.
Simple methods reduce input ripple for all charge pumps
News & Analysis 3/5/2003 Post a comment
Charge pumps are easy to use. But, the techniques employed to reduce capacitor size and optimise output current (fast switching speed and switches with low on-resistance) also produce noise and transient ripple. This Maxim applications expert offers advice (including theories of operation) for minimizing charge pump noise.
FFT plots provide insight to A/D performance
News & Analysis 3/4/2003 1 comment
Fast Fourier Transforms are good way of wringing performance data from A/D converter. In this terse-but-effective tutorial, Microchip Technology's famous analog applications guru offers some advice for interpreting the plots.