CX20505-14

The CX20505-14 Integrated Analog (IA) is a highly integrated device designed for use in multi-band GSM and GPRS handsets. This device implements all the voice-band, mixed signal, and radio control functions in a GSM/GPRS handset. In the receive path, the CX20505-14 digitizes the baseband In-Phase/Quadrature (I/Q) input, and outputs the digital samples on the device receive port.

The receive path features a PGA for AGC of the receive signal. In the transmit path, bursts of digital data are input to the device over the control port. The GMSK modulator CX20505-14 generates modulated I and Q waveforms from the input data. The I and Q waveforms are converted into analog waveforms and output from the device.

The CX20505-14 generates an analog signal to control the handset Power Amplifier (PA) output level. The signal is then input to the Power Amplifier Control (PAC) circuit. The voice-band Codec section provides an interface to a 32 Ω handset speaker and microphone. Line In/Out signals are also available for interfacing to audio accessories such as a headset or car kit. The device operates directly from a single cell, 3.6 V Li Ion battery with no external regulation required. The device features Low Drop Out (LDO) voltage regulators that generate the required device power supplies from the battery input.

A typical CX20505-14 application in a handset design is shown in Figure 1. The device is packaged in a compact, 104-pin (10mm x 10mm) Fine Pitch Ball Grid Array (FPBGA) see Error! Reference source not found...