C Device Address Input. Connect DEV_ADDR to GND, V
, SCL, or SDA. See Table 4.
Positive Power Supply. Bypass with a 0.1µF capacitor to GND.
Charge-Pump Negative Power Supply. Bypass with a 1µF capacitor to GND.
Detailed Description
The MAX9507 represents Maxim’s second-generation
of DirectDrive video amplifiers that meet the require-
ments of current and future portable equipment:
• 1.8V Operation: Eliminate the need for 3.3V supply in
favor of lower supply voltages.
• Lower Power Consumption: The MAX9507 reduces
average power consumption by up to 75% com-
pared to the 3.3V first generation (MAX9503/
MAX9505).
• Internal Fixed Gain of 8: As the supply voltages drop
for system chips on deep submicron processes, the
video DAC can no longer create a 1V
P-P
signal at its
output, and the gain of 2 found in the previous gen-
eration of video filter amplifiers is not enough.
• Load Reporting: The MAX9507 senses the presence
of a video load. For portable devices, a video load is
not connected most of the time, and turning off the
video encoder saves power. Another benefit of load
reporting is a simpler user interface, eliminating the
need to browse through menus to activate the video
output. Instead, the equipment will automatically
enable this feature.
• Dual SPST Analog Switches: The two analog switch-
es are ideal for routing additional audio, video, or
digital signals.
DirectDrive technology is necessary for a voltage-mode
amplifier to output a 2V
P-P
video signal from a 1.8V
supply. The integrated inverting charge pump creates
a negative supply that increases the output range and
gives the video amplifier enough headroom to drive a
2V
P-P
video signal into a 150Ω load.
DirectDrive
Background
Integrated video filter amplifier circuits operate from a
single supply. The positive power supply usually cre-
ates video output signals that are level-shifted above
ground to keep the signal within the linear range of the
output amplifier. For applications where the positive DC
level is not acceptable, a series capacitor can be
inserted in the output connection in an attempt to elimi-
nate the positive DC level shift. The series capacitor
cannot truly level shift a video signal because the aver-
age level of the video varies with picture content. The
series capacitor biases the video output signal around
ground, but the actual level of the video signal can vary
significantly depending upon the RC time constant and
the picture content.
