GC5322IZND Datasheet, PDF (2/4 Pages) Texas Instruments – Wideband Digital Pre-Distortion Transmit IC Solution

Crest factor reduction – Based on field-prov-
en technology, the GC5322’s CFR processing
block reduces the peak-to-average ratio (PAR)
for multi-channel/multi-carrier signals by
adding spectrally-shaped cancellation noise.
The CFR block has multiple stages, each having
configurable peak thresholds. This allows for
significant PAR reduction. Breakthrough power
efficiencies are achieved in the PA, while
maintaining spectral requirements and EVM
performance.
Digital pre-distortion – To limit possible
distortion in the transmit signal, the GC5322
includes an integrated DPD processing block.
The DPD block linearizes the PA, greatly
improving the adjacent channel leakage ratio
(ACLR). This allows PAs to meet stringent
spectral regulations and interference
requirements. Depending upon the PA, the
DPD block achieves ACLR improvements
of 20 to 30 dB or more.
The GC5322 interfaces directly to TI’s
TMS320C6727 DSP, which executes the
real-time adaptation algorithm. A real-time
feedback loop monitors the integrity of the
output signal to control the DPD’s operation.
The flexible algorithm supports multiple
PA architectures and emerging standards,
such as CDMA2000, WCDMA, TD-SCDMA,
OFDMA (WiMAX, LTE), HSPA and HSPA+.
TCK
RESETB SYNCD SYNC SYNC INT UPDATA UPADDR OEB RDB WRB CEB TRSTB TDO
(LVDS) ₃ OUT
16
10
TDI
TMS
4
BBCLK
DPDCLK
(LVDS)
BB
Input
format
BBFR
Gain
MPU interface
JTAG
DUC
CFR
Fractional
resampler
FB
(LVDS)
MFIO
(ADC input/
test output)
ADC
interface
TX
DAC
interface
Real to complex
(or bypass)
Bulk
interpolation
+ mixer
Feedback
equalizer
Tramsmit
equalizer
Feedback NL
correction
DPD
A detailed block diagram of the GC5322 showing the integration of three critical transmit functions:
DUC, CFR and DPD
HPI
CPRI/
OBSAI
BB I/Q
Data
Host
processor BB I/Q
Data
EMIF
C6727
SDRAM
(256 Mbit)
DSP
SPI
EMIF
GC5322
DUC-CFR-DPD
GC5322
DUC-CFR-DPD
I/Q
DAC5682z _I
DAC
Q
20 MHz RF card
I/Q
Modulator
TRF3703
HPA
ADC
ADS5527
Mixer
I/Q ^{DAC5682z I}
DAC
20 MHz RF card
I/Q
Q ^Modulator
HPA
TRF3703
Mixer
ADC
ADS5527
GC5322 in a dual-antenna configuration with up to 20 MHz of signal bandwidth