AD9701 Analog Devices, AD9701 Datasheet - Page 4

• Manufacturer Part Number: AD9701
• Description: 250 MSPS Video Digital-to-Analog Converter
• Manufacturer: Analog Devices

AD9701
Pin Name
GROUND
–V
BIT 1 (MSB)
BIT 2–BIT 7
BIT 8 (LSB)
STROBE
GROUND
SETUP
10% BRIGHT
COMPOSITE BLANKING
COMPOSITE SYNC
REFERENCE WHITE
COMPENSATION
CURRENT SET
OUTPUT
GROUND
S
Description
One of three ground returns. All grounds should be connected together near the AD9701.
Negative supply pin, nominally –5.2 V.
One of eight digital input bits. BIT 1 (MSB) is the most-significant-bit of the digital input word.
One of eight digital input bits.
One of eight digital input bits. BIT 8 (LSB) is the least-significant-bit of the digital input word.
Data and control register strobe input. STROBE is leading edge triggered.
One of three ground returns. All grounds should be connected together near the AD9701.
The SETUP input determines the position of the blanking level relative to the “reference black”
level (all data bits at logic “0”). The setup level is adjustable from 0 IRE units to 20 IRE units be-
low the reference black level (an IRE unit is 1% of the “grey scale” range).
SETUP LEVEL
0 IRE Units
7.5 IRE Units
10 IRE Units
20 IRE Units
10% BRIGHT adds an additional current to the output level, equal to roughly 10% of the “grey
scale” range. The 10% BRIGHT is active logic LOW and operates independently of all other inputs.
The COMPOSITE BLANKING input, active logic LOW, forces output to the blanking level set
with the SETUP input.
The COMPOSITE SYNC input, active LOW, creates a negative going horizontal synchronization
pulse relative to the blanking level. Under normal operating conditions, the COMPOSITE
BLANKING signal should precede and extend past the COMPOSITE SYNC signal. See SETUP
for additional information.
The REFERENCE WHITE input, active LOW, overrides the data inputs and forces the output to
the maximum “grey scale” level.
The COMPENSATION input insures adequate gain stability for the internal reference amplifier.
Under normal operating conditions, the COMPENSATION input is decoupled to ground through
a 0.1 F capacitor.
The CURRENT SET input determines the full-scale or “grey scale” range. The effects of the video
control functions are in addition to the “grey scale” range. (168
I
Analog output.
One of three ground returns. All grounds should be connected together near the AD9701.
OUTmax
4 I
SET
SYSTEM TIMING DIAGRAMS
FUNCTIONAL DESCRIPTION
= 4(1.26 V/R
SET
–4–
)
CONFIGURATION (PIN 21)
Ground
Open
Connection to –5.2 V through 1 k
Connection to –5.2 V
R
SET
600 ).
REV. A