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General Description

The MAX7461 single-channel loss-of-sync alarm (LOS)

provides composite video sync detection in NTSC,

PAL, and SECAM standard-definition television (SDTV)

systems. The MAX7461’s advanced detection circuitry

delivers robust performance by preventing false loss-

of-sync alarms due to noise. The device accepts an

AC-coupled composite (CVBS), luma (Y), or any other

video signal with sync, and outputs a logic-level signal.

The open-drain LOS output is low when no sync is

detected and high impedance when sync is detected.

The device operates from a single +5V supply.

The MAX7461 is available in a 5-pin SOT23 package

and is specified for operation over the -40°C to +85°C

temperature range.

Applications

Security Systems

Automotive Rear Seat Entertainment (RSE)

Systems

Consumer Electronics

Features

♦ Accepts CVBS, Y, or Any Other Video with Sync

♦ Loss-of-Sync Alarm Output

♦ Robust Performance in Noisy Environments

♦ Wire-OR Alarm Output

♦ NTSC, PAL, and SECAM

♦ Small 5-Pin SOT23 Package

MAX7461

Loss-of-Sync Alarm

________________________________________________________________ Maxim Integrated Products 1

19-0553; Rev 0; 5/06

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at

1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

Ordering Information

PART

TEMP RANGE

PIN-

PACKAGE

CODE

MAX7461EUK

-40°C to +85°C

5 SOT23-5 U5-2

GND

LOSGND

15V

MAX7461

SOT23-5

TOP VIEW

Pin Configuration

CLAMP

LPF

SYNC

DETECTOR

GND

LOS

75Ω

+5V

0.1µF

SYNC

SLICE

LEVEL

LOS

FILTER

0.1µF

1kΩ

SYNC

MAX7461

Functional Diagram

Summary of content (7 pages)

PAGE 1
9-0553; Rev 0; 5/06 Loss-of-Sync Alarm The MAX7461 single-channel loss-of-sync alarm (LOS) provides composite video sync detection in NTSC, PAL, and SECAM standard-definition television (SDTV) systems. The MAX7461’s advanced detection circuitry delivers robust performance by preventing false lossof-sync alarms due to noise. The device accepts an AC-coupled composite (CVBS), luma (Y), or any other video signal with sync, and outputs a logic-level signal.
PAGE 2
MAX7461 Loss-of-Sync Alarm ABSOLUTE MAXIMUM RATINGS VCC to GND ..............................................................-0.3V to +6V LOS to GND..............................................................-0.3V to +6V IN to GND.................-0.3V to the lower of +6V and (VCC + 0.3V) Continuous Power Dissipation (TA = +70°C) 5-Pin SOT23-5 (derate 7.1mW/°C above +70°C) ......571.0mW Maximum Current Into Any Pin .........................................±50mA Operating Temperature Range MAX7461EUK ...
PAGE 3
Loss-of-Sync Alarm LOS DETECT TIME vs. SUPPLY VOLTAGE MAX7461 toc01 LOS RELEASE TIME vs. SUPPLY VOLTAGE 4.0 MAX7461 toc02 3.0 TIME (ms) LOS 5V/div 3.5 TIME (ms) 2.5 IN 500mV/div 2.0 1.5 3.0 2.5 1.0 t = 10ms/div MAX7461 toc03 CVSB LOS ALERT TRANSIENT 2.0 4.5 4.7 4.9 5.1 5.3 5.5 4.5 4.7 SUPPLY VOLTAGE (V) SYNC HEIGHT LOS ALERT THRESHOLD vs. SUPPLY VOLTAGE 5.3 5.5 MAX7461 toc05 2.0 0.15 1.9 ICC (mA) SYNC HEIGHT (V) 5.1 SUPPLY CURRENT vs.
PAGE 4
Loss-of-Sync Alarm MAX7461 Pin Description PIN NAME FUNCTION 1 IN 2, 3 GND Ground 4 LOS Loss-Of-Sync Output (Open Drain). LOS is in high impedance when sync pulses are detected, and is pulled low when no horizontal sync signal is detected for more than the LOS detect time. LOS returns high when sync pulses are detected for more than the LOS release time. Connect a 1kΩ pullup resistor from LOS to VCC. 5 VCC Power-Supply Input. Bypass to GND with a 0.1µF capacitor. Video Input.
PAGE 5
Loss-of-Sync Alarm MAX7461 VCC 1kΩ µC MAX7461 0.1µF TV TUNER MONITOR 1 75Ω MAX7461 0.1µF RGB VIDEO SOURCE SWITCH MATRIX AND PROCESSING 75Ω MONITOR N MAX7461 0.1µF CAMERA 75Ω Figure 1.
PAGE 6
MAX7461 Loss-of-Sync Alarm VCC 1kΩ 1 µC N MAX7461 0.1µF CAM 1 MONITOR 1 VCC 75Ω 1kΩ MAX7461 0.1µF CAM 2 VCC SWITCH MATRIX AND PROCESSING 75Ω 1kΩ MONITOR N MAX7461 0.1µF CAM N 75Ω Figure 2.
PAGE 7
Loss-of-Sync Alarm SOT-23 5L .EPS PACKAGE OUTLINE, SOT-23, 5L 21-0057 E 1 1 Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.