MAXIM MAX7474 Technical data

General Description

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 qual­ity for cable lengths of up to 600m. The device automat­ically 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.

Applications

Security Video Systems

Video Switching Systems

Home Automation

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

Adaptive Equalizer for

Video Over Twisted Pair

________________________________________________________________

Maxim Integrated Products

1

19-3216; Rev 0; 1/08

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.

EVALUATION KIT

AVAILABLE

Ordering Information

+

Denotes a lead-free package.

Functional Diagram

Pin Configuration and Typical Application Circuit appear at
end of data sheet.

PART TEMP RANGE PIN-PACKAGE

MAX7474EAE+ -40°C to +85°C

16 SSOP
(5.3mm x 6.2mm)

PKG

CODE

A16+2

GND

0.1µF

V

+5V

CC

MAX7474

OUT

BACK-PORCH

CLAMP

BPLVL (1.0V TO 1.6V)

LOB

LOS

ADC

+5V

0.1µF

V

CC

0.022µF

0.022µF

INP

INN

FEQ0

FEQ1

CLAMP

ADAPTIVE

EQUALIZER

AGC AND AEQ

CONTROL

UNSHIELDED TWISTED PAIR

(0 TO 300m)

CAMERA

50Ω

50Ω

MAX7474

Adaptive Equalizer for
Video Over Twisted Pair

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VCC= +4.75V to +5.25V, RL= 150Ω (AC-coupled), FEQ1 = GND, FEQ0 = GND, V

BPLVL

= 1.4V, TA= -40°C to +85°C, unless otherwise

noted. Typical values are at T

A

= +25°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.

VCCto 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

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Differential Input
Operating Voltage

Maximum Differential
Input Operating Voltage

Output Voltage V

Output Sync Accuracy V

Output Burst Accuracy V

Differential Phase DP 0.3 Degrees

Differential Gain DG 0.3 %

Clamp Settling Time t

Back-Porch Level Input
Operating Range

Output Blank Level
Accuracy

Line-Time Distortion LTD 18µs, 100 IRE bar, DC-coupled output 1.2 %

LOS Threshold V

LOB Threshold V

Equalizer Response
Time

OUT Leakage Current I

Fixed Equalizer Gain A

V

IN-DIFF

OUT

SYNC_OUT

BURST_OUT

CLAMP

V

BPLVL

∆V

OUT-BL

LOS

LOB

t

EQ

LEAK

FEQ

AC-coupled, measured from sync tip to 100% white level
(Note 1)

AC-coupled, measured from sync tip to 100% white level 2.4 V

Measured from sync tip to 100% white level 1.0 V

210mV

76mV

Output blank level settles to < 5 IRE of final value from an
initial 100 IRE input error

(Note 2) ±55 mV

Measured differentially between INP and INN (Note 3) 40 mV

Measured at OUT with maximum equalizer gain (Note 4) 80 mV

Within ±10% of final value of the combined AGC and
AEQ gain from minimum to maximum

LOS mode, OUT is three-stated ± 0.01 ±10 µA

fSC = 3.58MHz

P-P

P-P

< V

< V

SYNC_IN-DIFF

BURST_IN-DIFF

1.0 V

< 600mV

< 300mV

FEQ1 = GND, FEQ0 = GND -1.5 0 +1.5

FEQ1 = GND, FEQ0 = V

FEQ1 = V

P-P

, fSC = 3.58MHz 242 293 344 mV

P-P

CC

, FEQ0 = GND 8.5 10.5 12.5

CC

263 293 323 mV

9 30 H Lines

1.0 1.6 V

16,384 H Lines

2.5 4.5 6.5

P-P

P-P

P-P

P-P

P-P

P-P

P-P

dB

MAX7474

Adaptive Equalizer for

Video Over Twisted Pair

_______________________________________________________________________________________ 3

Note 1: V

IN-DIFF = VINP

- V

INN

.

Note 2: V

OUT-BL = VBPLVL

+ ∆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.

ELECTRICAL CHARACTERISTICS (continued)

(VCC= +4.75V to +5.25V, RL= 150Ω (AC-coupled), FEQ1 = GND, FEQ0 = GND, V

BPLVL

= 1.4V, TA= -40°C to +85°C, unless otherwise

noted. Typical values are at T

A

= +25°C.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

DIGITAL INPUTS (FEQ0, FEQ1)

Input High Voltage V

Input Low Voltage V

Input Leakage Current Digital inputs = 0 or V

Input Capacitance C

DIGITAL OUTPUTS (LOS, LOB)

Output Low Voltage V

Output High Voltage V

POWER SUPPLY

Supply Voltage Range V

Supply Current I

DC Power-Supply
Rejection Ratio

OL

OH

CC

CC

PSRR

IH

IL

CC

IN

I

= 500µA 0.4 V

SINK

I

No load

20log(∆V
color burst

SOURCE

= 500µA

/∆V

CC

OUT-BlackLevel

Normal mode 47 59

LOS mode 24

), black video input with no

0.7 x
V

CC

± 0.01 ±10 µA

15 pF

V

CC

- 0.4

4.75 5.0 5.25 V

65 dB

0.3 x
V

CC

V

V

V

mA