Digital Predistortion Transmit Processor 352-Pin BGA

The GC5325 is a wideband digital predistortion transmit processor that includes a crest factor reduction (CFR) block and a digital predistortion (DPD) block with its associated feedback chain and capture buffers. The GC5325 processes composite input bandwidths of up to 20 MHz and processes DPD sample rates of up to 140 MHz. The GC5325 accepts a composite signal over an interleaved parallel interface at a data rate of up to 140 MSPS. The GC5325 CFR block reduces the peak-to-average ratio (PAR) of wideband digital signals provided in quadrature (I/Q) format, such as those used in third-generation (3G) code division multiple access (CDMA) wireless and orthogonal frequency division multiple access (OFDMA) applications. The GC5325 DPD block reduces adjacent-channel leakage ratio (ACLR), or out-of-band energy, by 20 dB to 30 dB or more. The efficiency of follow-on power amplifiers (PAs) is substantially improved by reducing the PAR and ACLR of digital signals. The digital-to-RF conversion can be further simplified by the fractional interpolator between the CFR and the DPD blocks, and a bulk upconverter (BUC) in the final stage of the GC5325. This feature typically eliminates the need for superheterodyne (dual-stage) upconversion architectures. Transmit and feedback NCO/mixers provide additional flexibility in the system frequency planning. 

Integrated CFR and DPD Functions

Up to 20-MHz Combined Signal Bandwidth

CFR: Typically Meets 3GPP TS 25.141 <6.5 dB PAR, <8 dB PAR for 802.16e Signals

DPD: Memory Compensation, Typical ACLR Improvement of 20 dB to 30 dB or More

Transmit- and Feedback-Channel Equalizers

352-Ball S-PBGA Package, 27 mm × 27 mm

1.2-V Core, 3.3-V I/O

Typical Power Consumption = 1.9 W

Flexible DSP Algorithm Supports Existing and Emerging Wireless Standards

Supports Direct Interface to TI High-Speed Data Converters

APPLICATIONS

• 3GPP (W-CDMA, TD-SCDMA) Base Stations
• 3GPP2 (CDMA2000) Base Stations
• WiMAX and WiBRO (OFDMA) Base Stations
• Multicarrier Power Amplifiers (MCPAs)