TMC22091/TMC22191
PRODUCT SPECIFICATION
Video
from
Encoder
Video
Output
1.8µH
75Ω
IN5818
+5V
75Ω
27pF
+5V
+5V
100
pF
75
Ω
47 µF
47 µF
1.0µH
330pF
330pF
0.1 µF
0.1 µF
BYPASS and OL
4-0
on TMC22191 only.
5
OL
4-0
V
D
GND
A
V
DDA
DO
GND
BYPASS
PD
23-0
VHSYNC
VVSYNC
PDC
LPF
LPF
LPF
CHROMA
LUMA
24
S-VIDEO OUTPUT
COMPOSITE
COMPOSITE VIDEO
OUTPUT
TMC22x91
DIGITAL VIDEO
ENCODER
KEY
V
DD
0.1 µF
COMP
LDV
PXCK
3.3KΩ
V
R
REF
LM185-1.2
8
CVBS
7-0
REF
392Ω
0.1µF
GHSYNC
GVSYNC
8
2
27007A
MICROPROCESSOR
INTERFACE
JTAG TEST
INTERFACE
Figure 35. Recommended Interface Circuit
Applications Discussion
The TMC22x91 is a complex mixed-signal VLSI circuit. It
converts digital video signals at clock rates of up to 30 MHz
to analog video outputs. A recommended circuit connection
is shown in Figure 35.
Interface to the TMC22071 Genlocking Video
Digitizer
The TMC22x91 Digital Video Encoder has been designed to
directly interface to the TMC22071 Genlocking Video Digi-
tizer. An interface circuit is shown in Figure 37. The micro-
processor interface for TMC22x91 and TMC22071 are
References
The circuit shown in Figure 35 uses a stable external 1.235V
voltage reference. To use the internal voltage reference, sim-
ply delete the 3.3kΩ resistor and the LM185-12. A simple
voltage divider from the power supply should NOT be used,
as any variations in power supply voltage would appear
directly on the video outputs.
similar. The R/W, RESET, D and A signals from the host
0
0
microprocessor are shared by the TMC22x91 and
TMC22071. The CS signals are separately driven from the
microprocessor bus.
Grounding Strategy
The TMC22x91 has distinctly separate analog and digital
circuits. To minimize digital crosstalk into the analog sig-
nals, the power supplies and grounds are provided over sepa-
rate pins. In general, the best results are obtained by
connecting all grounds to a ground plane. Power supply pins
should be individually decoupled at the pin.
Filtering
An simple low-pass output reconstruction filter is shown in
Figure 36. This filter is located in the video signal path after
the COMPOSITE, LUMA, and CHROMA outputs. The
value of R
may be varied to make up for the filter loss.
REF
Video
from
Encoder
Video
Output
1.8µH
75Ω
75Ω
27pF
75
Ω
1.0µH
330pF
330pF
100
pF
27025A
Figure 36. Recommended Output Reconstruction Filter
52
CADEKA [ CADEKA MICROCIRCUITS LLC. ]
