19-3216; Rev 0; 1/08
KIT
ATION
EVALU
BLE
AVAILA
Adaptive Equalizer for
Video Over Twisted Pair
General Description
Features
♦
Automatically Equalizes Up to 600m
(Fully Recovers Losses Up to 300m) of UTP Cable
Carrying CVBS
♦
Automatic Switchover to Fixed Equalization for
CVBS Without Color Burst
♦
Integrated Video Driver with Adjustable
Back-Porch Clamp Level
♦
LOS and LOB Output
♦
NTSC and PAL Compatible
♦
16-Pin SSOP Package
MAX7474
The MAX7474 adaptive equalizer recovers losses
incurred in the transmission of a composite video
(CVBS) signal over unshielded twisted-pair (UTP)
cable. The device fully recovers losses for cable
lengths of up to 300m and greatly improves signal qual-
ity for cable lengths of up to 600m. The device automat-
ically adapts to all cable lengths for CVBS signals with
color burst and allows fixed-equalization settings for
video signals without burst. The MAX7474 is optimized
to provide compensation for losses that occur when
transmitting composite video signals over UTP cables
such as Category 5e. The device compensates for low
frequency and chroma band losses. The MAX7474 is
compatible with NTSC and PAL standards.
The MAX7474 accepts differential input and provides a
single-ended output. The output is capable of driving
two AC- or DC-coupled standard 150Ω video loads.
The output back-porch DC level is adjustable with an
externally applied DC voltage at the BPLVL input. The
device also features loss-of-sync (LOS) and loss-of-burst
(LOB) logic outputs.
The MAX7474 is available in a 16-pin SSOP package
and is fully specified over the extended (-40°C to
+85°C) temperature range.
Ordering Information
PART
MAX7474EAE+
TEMP RANGE PIN-PACKAGE
-40°C to +85°C
16 SSOP
(5.3mm x 6.2mm)
PKG
CODE
A16+2
Applications
Security Video Systems
Video Switching Systems
Home Automation
+Denotes
a lead-free package.
Pin Configuration and Typical Application Circuit appear at
end of data sheet.
Functional Diagram
+5V
+5V
0.1µF
V
CC
0.022µF
UNSHIELDED TWISTED PAIR
(0 TO 300m)
CAMERA
INN
50Ω
0.022µF
50Ω
FEQ0
FEQ1
INP
CLAMP
0.1µF
V
CC
MAX7474
ADAPTIVE
EQUALIZER
OUT
ADC
BACK-PORCH
CLAMP
AGC AND AEQ
CONTROL
GND
BPLVL (1.0V TO 1.6V)
LOB
LOS
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
Adaptive Equalizer for
Video Over Twisted Pair
MAX7474
ABSOLUTE MAXIMUM RATINGS
V
CC
to GND ..............................................................-0.3V to +6V
All Other Pins to GND.............-0.3V to (min of 6V or V
CC
+ 0.3V)
Maximum Continuous Current into Any Input or Output .....±50mA
Continuous Power Dissipation (T
A
= +70°C)
16-Pin SSOP (derate 7.1mW/°C above +70°C) ........571.4mW
Operating Temperature Range ...........................-40°C to +85°C
Maximum Junction Temperature .....................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(V
CC
= +4.75V to +5.25V, R
L
= 150Ω (AC-coupled), FEQ1 = GND, FEQ0 = GND, V
BPLVL
= 1.4V, T
A
= -40°C to +85°C, unless otherwise
noted. Typical values are at T
A
= +25°C.)
PARAMETER
Differential Input
Operating Voltage
Maximum Differential
Input Operating Voltage
Output Voltage
Output Sync Accuracy
Output Burst Accuracy
Differential Phase
Differential Gain
Clamp Settling Time
Back-Porch Level Input
Operating Range
Output Blank Level
Accuracy
Line-Time Distortion
LOS Threshold
LOB Threshold
Equalizer Response
Time
OUT Leakage Current
Fixed Equalizer Gain
V
OUT
V
SYNC_OUT
V
BURST_OUT
DP
DG
t
CLAMP
V
BPLVL
∆V
OUT-BL
LTD
V
LOS
V
LOB
t
EQ
I
LEAK
A
FEQ
(Note 2)
18µs, 100 IRE bar, DC-coupled output
Measured differentially between INP and INN (Note 3)
Measured at OUT with maximum equalizer gain (Note 4)
Within ±10% of final value of the combined AGC and
AEQ gain from minimum to maximum
LOS mode, OUT is three-stated
FEQ1 = GND, FEQ0 = GND
f
SC
= 3.58MHz
FEQ1 = GND, FEQ0 = V
CC
FEQ1 = V
CC
, FEQ0 = GND
-1.5
2.5
8.5
1.2
40
80
16,384
±0.01
0
4.5
10.5
±10
+1.5
6.5
12.5
dB
Output blank level settles to < 5 IRE of final value from an
initial 100 IRE input error
1.0
SYMBOL
V
IN-DIFF
CONDITIONS
AC-coupled, measured from sync tip to 100% white level
(Note 1)
AC-coupled, measured from sync tip to 100% white level
Measured from sync tip to 100% white level
210mV
P-P
< V
SYNC_IN-DIFF
< 600mV
P-P
76mV
P-P
< V
BURST_IN-DIFF
< 300mV
P-P
, f
SC
= 3.58MHz
263
242
2.4
1.0
293
293
0.3
0.3
9
30
1.6
±55
323
344
MIN
TYP
1.0
MAX
UNITS
V
P-P
V
P-P
V
P-P
mV
P-P
mV
P-P
Degrees
%
H Lines
V
mV
%
mV
P-P
mV
P-P
H Lines
µA
2
_______________________________________________________________________________________
Adaptive Equalizer for
Video Over Twisted Pair
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= +4.75V to +5.25V, R
L
= 150Ω (AC-coupled), FEQ1 = GND, FEQ0 = GND, V
BPLVL
= 1.4V, T
A
= -40°C to +85°C, unless otherwise
noted. Typical values are at T
A
= +25°C.)
PARAMETER
SYMBOL
CONDITIONS
MIN
0.7 x
V
CC
0.3 x
V
CC
Digital inputs = 0 or V
CC
C
IN
V
OL
V
OH
I
SINK
= 500µA
I
SOURCE
= 500µA
V
CC
- 0.4
4.75
No load
Normal mode
LOS mode
5.0
47
24
65
5.25
59
±0.01
15
0.4
±10
TYP
MAX
UNITS
MAX7474
DIGITAL INPUTS (FEQ0, FEQ1)
Input High Voltage
Input Low Voltage
Input Leakage Current
Input Capacitance
Output Low Voltage
Output High Voltage
POWER SUPPLY
Supply Voltage Range
Supply Current
DC Power-Supply
Rejection Ratio
V
CC
I
CC
PSRR
V
mA
dB
V
IH
V
IL
V
V
µA
pF
V
V
DIGITAL OUTPUTS (LOS, LOB)
20log(∆V
CC
/∆V
OUT-BlackLevel
), black video input with no
color burst
Note 1:
V
IN-DIFF =
V
INP
- V
INN
.
Note 2:
V
OUT-BL =
V
BPLVL
+
∆V
OUT-BL
.
Note 3:
LOS is high when the input video sync amplitude goes below V
LOS
for 32 consecutive horizontal lines. LOS goes low when
the input video sync amplitude exceeds V
LOS
for 32 consecutive horizontal lines.
Note 4:
LOB is high when the output color burst amplitude goes below V
LOB
for 32 consecutive horizontal lines when at maximum
equalizer gain. LOB goes low when the output color burst amplitude exceeds V
LOB
for 32 consecutive horizontal lines.
_______________________________________________________________________________________
3
Adaptive Equalizer for
Video Over Twisted Pair
MAX7474
Typical Operating Characteristics
(V
CC
= 5V, R
L
= high impedance, f
SC
= 3.58MHz, Category 5e cable with active driver, T
A
= +25°C.)
MULTIBURST (0.5m CABLE)
MAX7474 toc01
MULTIBURST (300m CABLE)
MAX7474 toc02
75% COLOR BAR VECTOR DIAGRAM
(0.5m CABLE)
MAX7474 toc03
V
INP
-V
INN
200mV/div
V
INP
-V
INN
200mV/div
V
OUT
200mV/div
V
OUT
200mV/div
10µs/div
10µs/div
75% COLOR BAR VECTOR DIAGRAM
(300m CABLE)
DIFFERENTIAL PHASE (°) DIFFERENTIAL GAIN (%)
MAX7474 toc04
DIFFERENTIAL GAIN AND PHASE
(0.5m CABLE)
MAX7474 toc05
DIFFERENTIAL GAIN AND PHASE
(300m CABLE)
DIFFERENTIAL PHASE (°) DIFFERENTIAL GAIN (%)
0.2
0
-0.2
-0.4
0.4
0.2
0
-0.2
-0.4
0
1
2
3
4
5
MODULATED STEP
MAX7474 toc06
0.4
0.2
0
-0.2
-0.4
0.4
0.2
0
-0.2
-0.4
0
1
2
3
4
5
MODULATED STEP
0.4
2T RESPONSE (0.5m CABLE)
MAX7474 toc07
2T RESPONSE (300m CABLE)
MAX7474 toc08
12.5T RESPONSE (0.5m CABLE)
MAX7474 toc09
V
INP
-V
INN
200mV/div
V
INP
-V
INN
200mV/div
V
INP
-V
INN
200mV/div
V
OUT
200mV/div
V
OUT
200mV/div
V
OUT
200mV/div
200ns/div
200ns/div
500ns/div
4
_______________________________________________________________________________________
Adaptive Equalizer for
Video Over Twisted Pair
Typical Operating Characteristics (continued)
(V
CC
= 5V, R
L
= high impedance, f
SC
= 3.58MHz, Category 5e cable with active driver, T
A
= +25°C.)
18µs LINE-TIME DISTORTION
(0.5m CABLE)
MAX7474 toc11
MAX7474
12.5T RESPONSE (300m CABLE)
MAX7474 toc10
18µs LINE-TIME DISTORTION
(300m CABLE)
MAX7474 toc12
V
INP
-V
INN
200mV/div
V
INP
-V
INN
200mV/div
V
INP
-V
INN
200mV/div
V
OUT
200mV/div
V
OUT
200mV/div
V
OUT
200mV/div
500ns/div
5µs/div
5µs/div
NOISE SPECTRUM
(0.5m CABLE)
0
-5
-10
-15
-20
-25
-30
-40
-45
-50
-55
-60
-65
-70
-75
-80
-85
-90
-95
-100
1
2
3
4
FREQUENCY (MHz)
MAX7474 toc13
NOISE SPECTRUM
(300m CABLE)
0
-5
-10
-15
-20
-25
-30
-40
-45
-50
-55
-60
-65
-70
-75
-80
-85
-90
-95
-100
1
2
3
4
FREQUENCY (MHz)
MAX7474 toc14
NOISE LEVEL (dB)
NOISE LEVEL (dB)
5
5
_______________________________________________________________________________________
5
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