ADV7123JST330(RevB) View Datasheet(PDF) - Analog Devices
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ADV7123JST330 Datasheet PDF : 20 Pages
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ADV7123
PIN FUNCTION DESCRIPTIONS
Pin No. Mnemonic
Function
1–10
11
G0–G9
BLANK
12
SYNC
13, 29, 30 VAA
14–23 B0–B9
R0, G0, and B0 are the least significant data bits. Unused pixel data inputs should be connected to
either the regular PCB power or ground plane.
Composite Blank Control Input (TTL Compatible). A logic zero on this control input drives the analog
outputs, IOR, IOB, and IOG, to the blanking level. The BLANK signal is latched on the rising edge
of CLOCK. While BLANK is a logical zero, the R0–R9, G0–G9, and B0–B9 pixel inputs are ignored.
Composite Sync Control Input (TTL Compatible). A logical zero on the SYNC input switches off a
40 IRE current source. This is internally connected to the IOG analog output. SYNC does not over-
ride any other control or data input; therefore, it should only be asserted during the blanking interval.
SYNC is latched on the rising edge of CLOCK.
If sync information is not required on the green channel, the SYNC input should be tied to logical zero.
Analog Power Supply (5 V ± 5%). All VAA pins on the ADV7123 must be connected.
R0, G0, and B0 are the least significant data bits. Unused pixel data inputs should be connected to
either the regular PCB power or ground plane.
24
CLOCK
Clock Input (TTL Compatible). The rising edge of CLOCK latches the R0–R9, G0–G9, B0–B9,
SYNC, and BLANK pixel and control inputs. It is typically the pixel clock rate of the video system.
CLOCK should be driven by a dedicated TTL buffer.
25, 26
27, 31, 33
28, 32, 34
35
36
37
38
GND
IOB, IOG, IOR
IOB, IOG, IOR
COMP
VREF
RSET
PSAVE
Ground. All GND pins must be connected.
Differential Red, Green, and Blue Current Outputs (High Impedance Current Sources). These RGB
video outputs are specified to directly drive RS-343A and RS-170 video levels into a doubly terminated
75 Ω load. If the complementary outputs are not required, these outputs should be tied to ground.
Red, Green, and Blue Current Outputs. These high impedance current sources are capable of directly
driving a doubly terminated 75 Ω coaxial cable. All three current outputs should have similar output
loads whether or not they are all being used.
Compensation Pin. This is a compensation pin for the internal reference amplifier. A 0.1 µF ceramic
capacitor must be connected between COMP and VAA.
Voltage Reference Input for DACs or Voltage Reference Output (1.235 V)
A resistor (RSET) connected between this pin and GND controls the magnitude of the full-scale video
signal. Note that the IRE relationships are maintained, regardless of the full-scale output current. For
nominal video levels into a doubly terminated 75 Ω load, RSET = 530 Ω.
The relationship between RSET and the full-scale output current on IOG (assuming ISYNC is connected
to IOG) is given by:
RSET (Ω)
= 11,445 × VREF (V)/IOG (mA)
The relationship between RSET and the full-scale output current on IOR, IOG, and IOB is given by:
IOG (mA)
IOR, IOB (mA)
= 11,445 × VREF (V)/RSET (Ω) (SYNC being asserted)
= 7,989.6 × VREF (V)/RSET (Ω)
The equation for IOG will be the same as that for IOR and IOB when SYNC is not being used, i.e.,
SYNC tied permanently low.
Power Save Control Pin. Reduced power consumption is available on the ADV7123 when this pin is active.
39–48 R0–R9
Red, Green, and Blue Pixel Data Inputs (TTL Compatible). Pixel data is latched on the rising edge of
CLOCK.
REV. B
–9–
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