Circuit Description; Components Description - Kenwood KTI-3 Service Manual

1. MCU circuit
The MCU (IC10) 32bit microcontroller includes a 98kbit
chip SRAM.
2. Memory circuit
The flash memory has a capacity of 8Mbit (IC11) and
32Mbit (IC12).
3. Power supply circuit
The Power supply circuit consists of IC3 and IC7.
IC3 is a DC/DC converter and supplies 3.3V.
IC7 supplies 5.0V.
Interface unit (X46-3370-20)
Ref No. Part Name
IC1,2 IC RS-485 transceiver
IC3 IC DC/DC converter
IC4 IC Tri-state buffer
IC5 IC RS-232C driver/receiver
IC6 IC Ethernet transceiver
IC7 IC Voltage regulator
IC8 IC Voltage detector
IC10 IC MCU
IC11 IC Flash memory
IC12 IC Flash memory
Q1,3 Transistor DC switch (25M shift)
Q2 Transistor DC switch (SQ_OUT)
Q4,5 Transistor DC switch (12M shift)
Q6~9 Transistor DC switch (LED)
D1 Varistor Over current protection
D2 Zener diode Protection of reverse connection
D4 Schottky diode Catch diode (DC/DC converter)
D8 Diode Reverse current protection
D9 Zener diode Over voltage protection
D10 Schottky diode Over voltage protection
D11,12 LED Power/Status Indicator
D13~18 Diode Surge protection
D19~22 Varistor Surge protection

CIRCUIT DESCRIPTION

COMPONENTS DESCRIPTION

Description
4. LAN interface circuit
This circuit consists of IC6 and J20.
This interface circuit corresponds to 100Base-TX and
10Base-T.
KTI-3
5