SAA7740 Philips Semiconductors, SAA7740 Datasheet - Page 23

• Manufacturer Part Number: SAA7740
• Description: Digital Audio Processing IC DAPIC
• Manufacturer: Philips Semiconductors

Philips Semiconductors
APPLICATION INFORMATION
Clock circuit and oscillator
The clock generation of the SAA7740H is designed to
accommodate two main modes, the master and the slave.
In the master mode, the DAPIC is the master in the
system. The clock is generated by connecting a crystal to
the oscillator pins CLK1/XTAL1 and XTAL2 (see Fig.16).
In the slave mode, the DAPIC is supplied as a slave.
The external clock should be connected to the oscillator at
pin CLK1/XTAL1 (see Fig.17).
Crystal oscillator supply
The power supply for the oscillator is separate from the
other supply line. This is to minimize feedback from the
ground bounce of the IC to the oscillator. Pin V
ground supply and V
Power supply connection and EMC
The SAA7740H has in total 8 positive supply lines (V
including V
V
lines should be connected together on the printed
circuit-board. The ground supply lines should also be
connected together on the printed circuit-board.
To minimize radiation the IC should be placed on a
double-layer printed circuit-board with a large ground
plane on one side. The ground supply lines should have a
short connection to the ground plane. An LC network in the
positive supply lines can be used as a high frequency filter.
Test mode connections
Pins SCCLK, TSTCLK, TST1, TST2 and TST3 are used to
put the IC in the test mode and to test the internal
connections. In the application these pins must be
connected to ground.
1997 May 30
SSX.
Digital Audio Processing IC (DAPIC)
For correct current distribution all positive supply
DDX
, and 8 ground supply lines (V
DDX
is the positive supply.
SS
SSX
) including
is the
DD
)
23
handbook, halfpage
handbook, halfpage
external
clock
30 pF
10 pF
C1
10 pF
10 pF
Fig.16 Master mode.
C1
C2
Fig.17 Slave mode.
C2
nF
10
CLK1/XTAL1
CLK1/XTAL1
100
R1
C3
k
XTAL2
XTAL2
100
R1
k
56
59
MLC165
56
59
MLC164
Product specification
SAA7740H
max 1 V (p-p)