A CMOS 1.5-Bit ΣΔ DIGITAL IF TO RF TRANSMITTER FOR WCDMA APPLICATION |
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| Yongping Han, Shahin Mehdizad Taleie, Tino Copani, Bertan Bakkaloglu, Sayfe Kiaei |
- Abstract:
- A digital intermediate frequency (IF) to RF transmitter targeted for 2 GHz wideband code division multiple access (WCDMA) is presented. The proposed transmitter integrates a 3-level digital IF current-steering cell, an up-conversion mixer with a tuned load and an RF variable gain amplifier (RF VGA) with an embedded semidigital finite impulse response (FIR) reconstruction filter. A 4th-order 1.5-b IF bandpass sigma delta modulator (BP ΣΔM) is designed to guarantee in-band signal-to-noise ratio (SNR) and error vector magnitude (EVM) performances while the out-of-band quantization noise due to noise shaping is suppressed by the embedded FIR reconstruction filter to meet spectrum emission mask and ACPR requirements. The on-chip RF VGA provides 50 dB power scaling in 10-dB steps with less than 1 dB gain error. Together with the power control at the ΣΔM stage, the 74-dB dynamic range at RF frequency is achieved. The design is fabricated in a 4-metal 0.18-µm CMOS technology with a total core area of 0.8 × 1.6 mm². The IC delivers 0 dBm output power to the 50 Ω load at 2 GHz and it draws approximately 120 mA from a 1.8 V DC supply at the maximum output power.
- Keywords:
- digital transmitter, sigma-delta modulator, digital to analog converters (DACs), digital IF, RF variable gain amplifier (RF VGA), wideband code division multiple access (WCDMA)
- Download:
- IMEKO-IWADC-2011-65.pdf
- DOI:
- -
- Event details
- IMEKO TC:
- TC4
- Event name:
- IWADC 2011
- Title:
16th IMEKO International Workshop on ADC Modeling and Testing - Data Converter Design, Modeling and Testing (together with IEEE ADC Forum) (IWADC)
- Place:
- Orvieto, ITALY
- Time:
- 30 June 2011 - 01 July 2011