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3 - 13
(3) DDS LO CIRCUIT
The 40 MHz reference system clock is amplified at the
amplifiers (Q701, IC602, IC603), and is then applied to the
DSP IC (IC601). The applied signal is quintupled in the IC,
then uses 200 MHz DSP system clock signal.
The 200 MHz clock signal is divided 1/400, and then uses as
the 500 kHz sampling frequency of the A/D converter
(IC501).
3-6 POWER SUPPLY CIRCUITS
3-6-1 VOLTAGE LINES (DC-DC UNIT)
LINE
C15V
H8V
+15V
–12V
VDD1R5
5V
+8V
+5V
+3R3V
VDD3R3
DESCRIPTION
Common 15 V line from the REG unit. The volt-
age is applied to the LOGIC unit via the J3,
pin 6.
Common 8 V from the REG unit. The signal is
applied to the regulator circuits on the DC-DC
unit.
The same voltage as the +15 line passed
through the switching relay (RL142). The voltage
is applied to the PA200W board (via J420, pins 1
and 2), LOGIC (via the J820, pins 4–6) and
MAIN (via the J450, pin 3) units.
Common –12 V converted from the +15 V line
and regulated by the –12V regulator circuit
(IC121). The voltage is applied to the LOGIC (via
the J820, pin 3) and MAIN (via the J450, pin 2)
units.
Common 5 V converted from the H8V line and
regulated by the VDD1R5 regulator circuit
(IC101). The voltage is applied to the LOGIC unit
via the J821, pin 2.
Common 5 V converted from the H8V line and
regulated by the VDD5 regulator circuit (IC81).
The voltage is applied to the LOGIC (via the
J821, pin 4) and MAIN (via the J450, pin 10)
units.
The same voltage as the H8V line passed
through the switching relay (RL142). The voltage
is applied to LOGIC (via the J820, pin 7) and
MAIN (via the J450, pin 4) units.
Common 5 V converted from the +8V line and
regulated by the +5V regulator circuit (IC61). The
voltage is applied to the LOGIC (via the J820,
pin 8) and MAIN (via the J450, pin 4) units.
Common 3 V converted from the +8V line and
regulated by the +3R3V regulator circuit (IC41).
The voltage is applied to the LOGIC (via the
J820, pin 9) and MAIN (via the J450, pins 6–8)
units.
Common 3 V converted from the H8V line and
regulated by the VDD3R3 regulator circuit
(IC21). The voltage is applied to the LOGIC unit
via the J821, pin 3.
Summary of Contents for IC-7800
Page 1: ...SERVICE MANUAL ADDENDUM CONTENTS PARTS LIST 1 BOARD LAYOUTS 65 VOLTAGE DIAGRAM 67 Dec 2009 ...
Page 79: ...SERVICE MANUAL ADDENDUM CONTENTS PARTS LIST 1 BOARD LAYOUTS 60 VOLTAGE DIAGRAM 64 Feb 2009 ...
Page 157: ...SERVICE MANUAL ADDENDUM CONTENTS PARTS LIST 1 BOARD LAYOUTS 57 VOLTAGE DIAGRAM 59 Aug 2008 ...
Page 245: ...SERVICE MANUAL ADDENDUM CONTENTS PARTS LIST 1 BOARD LAYOUTS 57 VOLTAGE DIAGRAM 59 Jul 2008 ...
Page 333: ...THE TRANSCEIVER i7800 SERVICE MANUAL S 14015HZ C1 2 Mar 2006 ...
Page 555: ...1 1 32 Kamiminami Hirano ku Osaka 547 0003 Japan S 14015HZ C1 2 C 2004 2006 Icom Inc ...