The analog baseband receiver provides twelve filtering modes, a wide gain range, low noise, high linearity and integrated DC offset compensation. The filter can be configured as a complex poly-phase bandpass for low IF architectures giving image rejection, or as a low pass filter for direct conversion systems. It also has configurable bandwidth.
A 2nd order filter provides attenuation of close-in interferers. A third real low pass pole is incorporated to improve out of band rejection. A calibration block is used to calibrate all poles and zeros to within +/-3% of the nominal value. The baseband provides VGA functionality with a programmable gain range of +10dB to +24dB in 1dB steps.
An optional servo loop around the filter can provide continuous DC offset compensation in low pass mode and a high pass cut-off frequency of 1.5KHz over all gain settings.
An optional fast settling auto-zeroing DC offset scheme can be employed to reduce offset to acceptable levels in the guard time between time slots in a TDMA system. In polyphase asymmetric band-pass mode the filter’s transfer function means DC offset correction is not required.
- TSMC 180nm RF CMOS process
- Configurable in Low-IF Poly-Phase Band-Pass or Low Pass Modes
- Configurable Pass-Band Bandwidth
- Configurable in TX or RX Modes
- Image Rejection Calibration to Improve Native Image Rejection from 35dB to 50dB
- 3V Power Supply
- Programmable Gain from +10dB to +24dB in 1dB Steps
- Input Referred Noise Voltage of 35nV/rt-Hz at Maximum Gain Setting
- High Linearity for Tolerance of Large Interferers
- Output 1dB Compression Voltage >2.5Vpp Over All Gain
- Filter Calibration Used to Trim Cut-Off Frequency of Filter to Accuracy of +/-3%
- I/Q Amplitude Mismatch < 2%
- I/Q Phase Mismatch < 0.5º
- Output Buffer Suitable for Driving ADC
- Built-in Bandgap and Biasing Block
- Current Consumption = 13mA
- Compact Die Area = 1.1mm2
- Flat Netlist (cdl)
- Layout View (gds2)
- Abstract View (lef)
- Behavioral Model (VHDL/Verilog/VerilogAMS)
- Verification Plan and Report
- Integration Support
- Proprietary ISM Band
- Satellite Communications
Block Diagram of the Analog RX/TX Baseband