Circuit Description Of Cordless Handset Pwb - Sharp FO-CC500 Service Manual

FO-CC500A
FO-K01A
[5] Circuit description of Cordless
handset PWB
1. Cordless handset configuration
LCD
RECEIVER
CORDLESS
HANDSET
SPEAKER
1) Cordless handset PWB
The block diagram is shown below.
CODEC
RF
MODULE
1 1 1 1 1
MERLIN (R6815)(IC5): pin-128 QFP
The MERLIN is mainly consist of MC19 controller, DSP core,
Baseband Modem and internal RAM.
Crystal frequency is 19.2 MHz.
The system clock is 9.6 MHz.
2 2 2 2 2
SST39LF512P(IC3): pin-32 TSOP (FLASH ROM)
This memory store the program for MERLIN.
It is able to change the program by using download tool.
3 3 3 3 3
S-24C04(IC4): pin-8 SOP (EEPROM)
This is nonvolatile memory. The memory size is 4 Kbits.
It is stored the system ID, channel number etc.
4 4 4 4 4
20438(IC8): pin-32 QFP (CODEC)
This part is adjust the signal level from mic/to receiver.
And it convert the signal from analog to digital or from digital to
analog.
5 5 5 5 5
TMX964A(UNIT1): pin-26 SOP (RF MODULE)
This part is modulated the baseband signal to 2.4 GHz band radio
frequency.
It consist of RF109, RF110 made by CONEXANT and VCO for
oscillating 2.4 GHz etc.
RF109 is 2.4 GHz DSS Transceiver. The main function are that
LNA/Quadrature mixer from RF down to baseband and mixer for
baseband to RF modulation.
Transmitter output levels are selectable for high, medium, and low
power modes.
LNA gains are selectable for high and low modes.
RF110 is a three stage class AB power amplifier for 2.4 GHz band.
ANTENNA
HEADSET
(OPTION)
PWB
BATTERY
Fig. 13
FLASH
ROM
MERLIN
EEPROM
Fig. 14
2) LCD(GPM190A0)
This LCD is COG type.
Its display format is 15charactor × 3line dot matrix and display mode
is STN.
3) RECEIVER(DTR-208H)
This part is Dynamic receiver with Hearing Aid to meet FCC regu-
lation.
4) SPEAKER(DSH-305)
This is Dynamic Mylar Speaker. Output impedance is 32 Ω at
1 kHz.
5) BATTERY(3HR-5/4AAAU)
This is Nickel Metal Hydride Rechargeable Battery.
It consists of 3cell battery, poly switch, cable and 2pin connector.
The normal voltage is 3.6 V, and the typical capacity is 850 mAh.
6) HANDSET
Handset is able to communicate with hands free by using Hand-
set.
The meat plug size is φ 2.5.
7) ANTENNA
Antenna type is Whip antenna.
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