A Small-Chip-Area Transceiver IC for Bluetooth Featuring a Digital Channel-Selection Filter

Masaru KOKUBO
Masaaki SHIDA
Takashi OSHIMA
Yoshiyuki SHIBAHARA
Tatsuji MATSUURA
Kazuhiko KAWAI
Takefumi ENDO
Katsumi OSAKI
Hiroki SONODA
Katsumi YAMAMOTO
Masaharu MATSUOKA
Takao KOBAYASHI
Takaaki HEMMI
Junya KUDOH
Hirokazu MIYAGAWA
Hiroto UTSUNOMIYA
Yoshiyuki EZUMI
Kunio TAKAYASU
Jun SUZUKI
Shinya AIZAWA
Mikihiko MOTOKI
Yoshiyuki ABE
Takao KUROSAWA
Satoru OOKAWARA

Publication
IEICE TRANSACTIONS on Electronics   Vol.E87-C    No.6    pp.878-887
Publication Date: 2004/06/01
Online ISSN: 
DOI: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Analog Circuit and Device Technologies)
Category: 
Keyword: 
Bluetooth transceiver,  low-IF,  VCO,  channel-selection filter,  

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Summary: 
We have proposed a new low-IF transceiver architecture to simultaneously achieve both a small chip area and good minimum input sensitivity. The distinctive point of the receiver architecture is that we replace the complicated high-order analog filter for channel selection with the combination of a simple low-order analog filter and a sharp digital band-pass filter. We also proposed a high-speed convergence AGC (automatic gain controller) and a demodulation block to realize the proposed digital architecture. For the transceiver, we further reduce the chip area by applying a new form of direct modulation for the VCO. Since conventional VCO direct modulation tends to suffer from variation of the modulation index with frequency, we have developed a new compensation technique that minimizes this variation, and designed the low-phase noise VCO with a new biasing method to achieve large PSRR (power-supply rejection ratio) for oscillation frequency. The test chip was fabricated in 0.35-µm BiCMOS. The chip size was 3 3 mm2; this very small area was realized by the advantages of the proposed transceiver architecture. The transceiver also achieved good minimum input sensitivity of -85 dBm and showed interference performance that satisfied the requirements of the Bluetooth standard.