MAX9532AUB+T Maxim Integrated Products, MAX9532AUB+T Datasheet - Page 7

• Manufacturer Part Number: MAX9532AUB+T
• Description: IC AMP VID DIRECTDRIVE 10-MSOP
• Manufacturer: Maxim Integrated Products
• Series: DirectDrive™r

Specifications of MAX9532AUB+T

• Applications: Automotive Systems
• Number Of Circuits: 1
• Current - Supply: 15mA
• Current - Output / Channel: 90mA
• Voltage - Supply, Single/dual (±): 3 V ~ 3.6 V
• Mounting Type: Surface Mount
• Package / Case: 10-MSOP, Micro10™, 10-uMAX, 10-uSOP
• For Use With: MAX9532EVKIT+ - EVALUATION KIT FOR MAX9532
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The MAX9532 DirectDrive video amplifier with short-to-
battery protection features an internal 5-pole
Butterworth lowpass filter with the amplifier configured
with a gain of 4. The MAX9532 accepts DC-coupled or
AC-coupled full-scale input signals of 0.5V
Integrated short-to-battery protection prevents the
MAX9532 from being damaged when the output is
short circuited to the battery in automotive applications.
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 to eliminate the posi-
tive DC level shift. The series capacitor cannot truly
level shift a video signal because the average level of
the video varies with picture content. The series capaci-
tor 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.
The series capacitor creates a highpass filter. Since the
lowest frequency in video is the frame rate, which is
between 24Hz and 30Hz, the pole of the highpass filter is
ideally an order of magnitude lower in frequency than
the frame rate. Therefore, the series capacitor must
be very large, typically from 220µF to 3000µF. For
space-constrained equipment, the series capacitor is
PIN
10
1
2
3
4
5
6
7
8
9
JACKSENSE Jack-Sense Input. Connect to the video output connector after the back-termination resistor.
CPGND
CPVSS
NAME
GND
C1N
OUT
V
C1P
_______________________________________________________________________________________
V
IN
DD
SS
Detailed Description
Positive Power Supply. Bypass V
Charge-Pump Flying Capacitor Positive Terminal. Connect a 1µF ceramic capacitor from C1P to C1N.
Charge-Pump Ground. Connect to GND.
Charge-Pump Flying Capacitor Negative Terminal. Connect a 1µF ceramic capacitor from C1P to
C1N.
Charge-Pump Negative Power Supply. Bypass CPVSS with a 1µF ceramic capacitor in parallel with a
10nF low ESL capacitor to GND.
Negative Power Supply. Connect V
Video Output
Ground
Video Input
DirectDrive Video Amplifier with
DirectDrive
Background
Short-to-Battery Protection
P-P
.
DD
SS
with a 1µF capacitor to GND.
to CPVSS.
unacceptable. Changing from a single series capacitor to
a SAG network that requires two smaller capacitors can
only reduce space and cost slightly.
When the full-scale video signal from a video DAC is
500mV, the black level of the video signal created by
the video DAC is around 150mV. The MAX9532 shifts
the black level to near ground at the output so that the
active video is above ground and the sync is below
ground. The amplifier needs a negative supply for the
output stage to remain in the linear region when driving
sync below ground.
The MAX9532 includes an integrated charge pump and
linear regulator to create a low-noise negative supply
from the positive supply voltage. The charge pump
inverts the positive supply to create a raw negative volt-
age that is then fed into the linear regulator filtering out
the charge-pump noise.
The actual level of the video signal varies less with a
DirectDrive output than with an AC-coupled output. The
average video signal level changes depending upon
the picture content. With an AC-coupled output, the
average level changes according to the time constant
formed by the series capacitor and series resistance
(usually 150Ω). For example, Figure 1 shows an AC-
coupled video signal alternating between a completely
black screen and a completely white screen. Notice the
excursion of the video signal as the screen changes.
FUNCTION
Comparison Between DirectDrive Output
and AC-Coupled Output
Pin Description
Video Amplifier
7