MAX4079 Просмотр технического описания (PDF) - Maxim Integrated

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MAX4079

Complete Audio/Video Backend Solution

Maxim Integrated 

Complete Audio/Video

Backend Solution

Pin Description

PIN

1

2, 24

3

4, 21

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

22

23

NAME

REXT

VVID

CVBSIN

GVID

YIN

CBYPASS

CIN

AUDV

LINP

LINN

RINN

RINP

ROUT2

ROUT1

GAUD

MONO

LOUT2

LOUT1

COUT

YOUT

CVBSOUT1

CVBSOUT2

FUNCTION

External Filter Resistor. Bypass with a 10kΩ ±1% resistor and a 0.1µF capacitor to GVID.

Video Power-Supply Input

Composite Video Input

Video Ground

Luma Input

Audio LDO Regulator Bypass Capacitor. Bypass with a1µF capacitor to GAUD.

Chroma Input

Audio Power-Supply Input

Left-Channel Audio Positive Input

Left-Channel Audio Negative Input

Right-Channel Audio Negative Input

Right-Channel Audio Positive Input

Right-Channel Audio Output 2

Right-Channel Audio Output 1

Audio Ground

Mono Audio Output

Left-Channel Audio Output 2

Left-Channel Audio Output 1

Chroma Video Output

Luma Video Output

Composite Video Output 1

Composite Video Output 2

Detailed Description

The MAX4079 filters and buffers video (NTSC/PAL/DVB)

and stereo audio signals from the MPEG decoder of a

cable/satellite receiver, VCR/DVD player, or a TV to an

external load. The MAX4079 has luma-chroma (Y-C)

and composite (CVBS) video inputs with one Y-C and

two CVBS outputs. All video inputs are AC-coupled with

internal DC biasing on the chroma input and active

clamps for the luma and composite.

The MAX4079 video reconstruction filters have a 6MHz

cutoff frequency and 50dB attenuation at 27MHz. The

filters are matched, with flat group delay for standard-

definition video. The video gain is fixed at +6dB to drive

a 75Ω back-terminated load (150Ω) to unity gain. The

video outputs can be either DC- or AC-coupled and are

powered by a single +5V supply.

The MAX4079 audio amplifiers have differential inputs

for optimum performance, but can be used with single-

ended sources with external biasing. The audio chan-

nels have a fixed gain of +6dB and deliver 2.6VRMS

output with a differential input of ±1.85V. The audio

amplifiers operate from a +9V to +12V single supply

and feature an internal bias generator. An on-chip

mixer also provides a mono output, with +3dB gain,

derived from the left and right audio channels.

Video

The video section of the MAX4079 implements DC

restore/biasing, amplification, and reconstruction filter-

ing for the Y-C and CVBS input signals. All of the video

inputs are AC-coupled. DC restore is performed using

a sync tip clamp for both luma and composite video

channels. The chroma DC level input is biased at the

midlevel of the signal.

All video channels have a fixed gain of +6dB. The DC

level at the video outputs is controlled so that coupling

capacitors are not required.

All composite and luma video outputs are capable of

driving 2.4VP-P, and the chroma output is capable of

driving 1.8VP-P into 150Ω resistive load to ground. Up

to 35pF of load capacitance can be tolerated at each

video output without stability or slew-rate issues.

8 _______________________________________________________________________________________

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