Baseband Module JP3 Technical Documentation
The baseband module consists of VCTCXO module and four ASIC circuits, PSA, CHAPS, NASTA 4.5, EEPROM, and some standard circuits, DUAL BILATERAL SWITCH (TC7W66F), AUDIO POWER AMPLIFIER (LM4862) and a Hitachi H8 series controller (H8/3093 MCU).
The MCU includes memories, 192 kbytes ROM and 4 kbytes RAM. It controls all transceiver functions.
The EEPROM type is 4 kbytes with 32 bytes. The OTP memory is a serial I2C-bus type.
The baseband is running from a 2.8 V power rail, which is supplied by a power controlling asic. In the PSA asic there are two separate power supplies for BaseBand ( VA,VL ) and two externally controllable power supplies for RF (VRX, VTX).
The CHAPS is a charging control ASIC. It is essentially an integrated power switch for controlling charging current, in a mobile phone. CHAPS is designed for 3 cell Nickel or 1 cell Lithium battery packs.
The NASTA circuit integrates the Audio and Modem operations. Because the NASTA supports only one microphone, there are two bilateral switches to connect the internal microphone or the headset microphone to the NASTA MIC input. There is an audio power amplifier for EAR and XEAR lines each. The internal earphone amplifier is a dual ended type output which is in EAR line and there is transistor buffer in XEAR line.
The VCTCXO module is a voltage and temperature controlled oscillator which operates as system clock for RF and BaseBand.
All functional blocks of the baseband are mounted on a single multi layer printed circuit board. All components of the baseband are surface mount-able. This board contains also the RF-parts. The B-cover side ( battery side ) EMC shielding is implemented by using a metallic RF-shields on the RF-blocks. On the other side the engine is shielded with a aluminium frame, which makes a contact to a ground ring of the engine board and a ground plane of the UI-board.
The connections from BaseBand to UI board are fed through a 28-way 2-row board to board spring connector.
Baseband Module JP3
Modes of Operation
Power off, Standby, Listening and Conversation modes.
- In Power off mode only the circuits needed for power up are supplied.
- In Standby mode the MCU and needed blocks of the NASTA are active.
- In Listening mode the receiver and some blocks of the NASTA are active.
- In Conversation mode all ICs are active.
Baseband Module JP3
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