
2000 Aug 02
30
Philips Semiconductors
Product specication
5 V mixers/oscillators and synthesizers for
cable TV and VCR 2-band tuners
TDA6502; TDA6502A;
TDA6503; TDA6503A
Table 19 Transistors
13.3
Tuning amplier
The tuning amplifier is capable of driving the varicap
voltage without an external transistor. The tuning voltage
output must be connected to an external load of 22 k
which is connected to the tuning voltage supply rail.
The loop filter design depends on the oscillator
characteristics and the selected reference frequency.
13.4
Crystal oscillator
The crystal oscillator uses a 4 MHz crystal connected in
series with an 18 pF capacitor thereby operating in the
series resonance mode. Connecting the crystal to the
ground is preferred, but it can also be connected to the
supply voltage.
13.5
Examples of I2C-bus data format sequences for
TDA6502 and TDA6503
Tables 20 to 24 show the various write sequences where:
S = START bit
A = acknowledge bit
P = STOP bit.
Conditions:
fxtal = 4 MHz
N = 1600
fosc = 100 MHz
fstep = 62.5 kHz
Port register VHFL is ‘on’ to switch-on band VHF low
Port register FMST is ‘on’ to switch-on an FM sound trap
ICP = 280 A.
COMPONENT
VALUE
TR1
BC847B
TR2
BC847B
13.5.1
WRITE SEQUENCES TO REGISTER C2
Table 20 Complete sequence with rst the divider bytes (rst data bit = 0)
Table 21 Complete sequence with rst the control and band-switch bytes (rst data bit = 1)
Table 22 Sequence with divider bytes only (rst data bit = 0)
Table 23 Sequence with control and band-switch bytes only (rst data bit = 1)
Table 24 Sequence with control byte only (rst data bit = 1)
START
ADDRESS
BYTE
ACK
DIVIDER
BYTE 1
ACK
DIVIDER
BYTE 2
ACK
CONTROL
BYTE
ACK
BAND-
SWITCH
BYTE
ACK
STOP
S
C2
A
06
A
40
A
CE
A
09
A
P
START
ADDRESS
BYTE
ACK
CONTROL
BYTE
ACK
BAND-
SWITCH
BYTE
ACK
DIVIDER
BYTE 1
ACK
DIVIDER
BYTE 2
ACK
STOP
S
C2
A
CE
A
09
A
06A40A
P
START
ADDRESS BYTE
ACK
DIVIDER BYTE 1
ACK
DIVIDER BYTE 2
ACK
STOP
S
C2
A
06A40A
P
START
ADDRESS BYTE
ACK
CONTROL BYTE
ACK
BAND-SWITCH BYTE
ACK
STOP
S
C2
A
CE
A09A
P
START
ADDRESS BYTE
ACK
CONTROL BYTE
ACK
STOP
SC2
A
CE
A
P