ADV7177KS-REEL Analog Devices Inc, ADV7177KS-REEL Datasheet - Page 42

• Manufacturer Part Number: ADV7177KS-REEL
• Description: IC DAC VIDEO NTSC 3-CH 44MQFP
• Manufacturer: Analog Devices Inc
• Type: Video Encoderr

Specifications of ADV7177KS-REEL

• Rohs Status: RoHS non-compliant
• Applications: Set-Top Boxes, TV
• Voltage - Supply, Analog: 3 V ~ 3.6 V
• Mounting Type: Surface Mount
• Package / Case: 44-MQFP, 44-PQFP
• Adc/dac Resolution: 9b
• Screening Level: Commercial
• Package Type: MQFP
• Pin Count: 44
• Voltage - Supply, Digital: -
• Lead Free Status / RoHS Status: Not Compliant

ADV7177/ADV7178
OPTIONAL DAC BUFFERING
For external buffering of the ADV7177/ADV7178 DAC
outputs, the configuration in Figure 65 is recommended. This
configuration shows the DAC outputs running at half (18 mA)
their full-current (34.7 mA) capability. This allows the devices
to dissipate less power; the analog current is reduced by 50%
with a RSET of 300 Ω and a RLOAD of 75 Ω. This mode is
recommended for 3.3 V operation as optimum performance is
obtained from the DAC outputs at 18 mA with a V
This buffer also adds extra isolation on the video outputs, as the
buffer circuit in Figure 66 shows. When calculating absolute
output full current and voltage, use the following equation:
where K = 4.2146 constant, V
V
I
OUT
OUT
=
= I
(
V
OUT
REF
R
SET
× R
×
K
LOAD
)
REF
= 1.235 V
AA
of 3.3 V.
Rev. C | Page 42 of 44
300Ω
PIXEL
PORT
FILTER O/P
OPTIONAL
INPUT/
R SET
Figure 65. Output DAC Buffering Configuration
Figure 66. Recommended Output DAC Buffer
V
V
DIGITAL
REF
CORE
AA
ADV7177/ADV7178
4
3
AD8051
V
V
CC
CC
5
2
DAC A
DAC B
DAC C
+
–
1
OUTPUT TO
TV MONITOR
OUTPUT
OUTPUT
BUFFER
OUTPUT
BUFFER
BUFFER
75Ω
75Ω
75Ω