CX20524

The CX20524 Mixed Signal Device (MSD) is a highly integrated device designed for use in multi-band Global System for Mobile communications (GSM) and General Packet Radio Service (GPRS) handsets. The MSD includes all the power management, voice-band, mixed signal, and radio control functions required in a GSM/GPRS handset and module.

In the receive path, the MSDCX20524 digitizes the baseband In- Phase/Quadrature (I/Q) inputs. Digital samples CX20524 are then sent to the Baseband Processor (BP) via the Rx serial interface. The receive path features a programmable gain amplifier (PGA) for Automatic Gain Control (AGC) of the receive signal. In the transmit path, bursts of digital data are input to the MSD over the control port. A Gaussian Minimum-Shift Keying (GMSK) modulator generates modulated I and Q waveforms from the input data. The I and Q waveforms are converted into analog waveforms and output from the MSD.

The CX20524 generates an analog signal to control the handset Power Amplifier (PA) output level. The device voiceband Codec section provides an interface to a 32 Ω handset speaker and microphone. Line In/Out signals are also available to interface with audio accessories, such as a headset or car kit.

The MSD CX20524 is designed to operate directly from a single cell, 3.6 V Li Ion battery with no external regulation required. The MSD integrates all necessary Low Drop Out (LDO) voltage regulators that generate the required device and system power supplies from battery input. An integrated SIM interface circuit allows direct interface to 3.0 V and 1.8 V SIM cards with no external components. An integrated battery charger control circuit provides charging capabilities for multi-chemistry batteries.

The CX20524-12 is packaged in a compact, 160-pin (12 mm x 12 mm) Fine Pitch Ball Grid Array (FPBGA), shown in Figure 2. The CX20524-13 is packaged in a compact, 180 pin 10 mm x 10 mm, 0.5 mm pitch, Fine Pitch Ball Grid Array (FPBGA), shown in Figure 3.