MAXIM MAX7445 Technical data

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General Description

The MAX7445 4-channel, buffered video reconstruction filter is ideal for anti-aliasing and DAC-smoothing video applications or wherever analog video is reconstructed from a digital data stream (such as cable/satellite/terrestrial set-top boxes, DVD players, hard-disk recorders (HDRs), and personal video recorders (PVRs)). This device operates from a single +5V supply and has a flat passband out to 5MHz with a stopband attenuation of 43dB at 27MHz. This makes it ideal for use with NTSC, PAL, and standard-definition digital TV (SDTV) video systems. Each output is capable of driving two standard 150Ω video loads.

The MAX7445 has three modes of operation. Mode 1 processes CVBS and RGB video signals. Mode 2 processes CVBS, Y, and C signals, as well as a second asynchronous CVBS video signal. Mode 3 processes RGB and CVBS (asynchronous) video signals. An external pin adjusts the gain of the video buffer to either +6dB, +9.5dB, or +12dB to accommodate video-encoder DAC output signals of <1V. High-frequency boost circuitry provides picture sharpness with +1.2dB of gain boost without degradation in the stopband. The output video drivers can be disabled with an external pin.

The MAX7445 is available in a 14-pin TSSOP package with an exposed pad, and is specified over the -40°C to +85°C extended temperature range.

Applications

Set-Top Boxes/HDRs DVD Players

Game Consoles Digital VCRs

Desktop Video Editors

Features

♦ 4-Channel Filter and Buffer for CVBS, RGB, or Y/C

Video Signals

♦ Filter Response Ideal for NTSC, PAL, and

Interlaced SDTV Video Signals

♦ 43dB (typ) Stopband Attenuation at 27MHz

♦ ±0.75dB (max) Passband Ripple Out to 5MHz

♦ Blanking Level Voltage on Cable <1V

♦ Each Channel Drives Two 150Ω Video Loads

♦ +5V Single-Supply Voltage

♦ Selectable Gain: +6dB, +9.5dB, and +12dB

♦ Small 14-Pin TSSOP Package

MAX7445

4-Channel Video Reconstruction Filter

________________________________________________________________ Maxim Integrated Products 1

Functional Diagram

Ordering Information

19-2948; Rev 0; 8/03

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.

*EP = Exposed pad.

Pin Configuration appears at end of data sheet.

PART TEMP RANGE PIN-PACKAGE

MAX7445EUD -40°C to +85°C 14 TSSOP-EP*

ENCODER

0.1µF INA

D/A

0.1µF

D/A

0.1µF

D/A

SELECT

0.1µF

D/A

LOWPASS

FILTER

INB

LOWPASS

FILTER

INC

LOWPASS

FILTER

IND

LOWPASS

FILTER

SYNC

DETECTOR

SYNC

DETECTOR

GND

75Ω

MAX7445

DISABLE

OUTA

OUTB

OUTC

OUTD

GAIN

75Ω

*OPTIONAL CAPACITORS

MAX7445

4-Channel Video Reconstruction Filter

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VCC= +5V ±5%, CL= 0 to 20pF, RL= 75Ω to GND for DC-coupled load, RL= 75Ω to VCC/ 2 for AC-coupled load, C

IN_

= 0.1µF,

GAIN = GND (+6dB) or V

(+9.5dB), TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at VCC= +5V, TA= +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 ...........................................................................+6V

All Other Pins to GND.................................-0.3V to (V

+ 0.3V)

Maximum Current into Any Pin Except V

and GND .....±50mA

Continuous Power Dissipation (T

= +70°C)

TSSOP-EP (derate 20.8mW/°C above +70°C)...........1667mW

Operating Temperature Range ...........................-40°C to +85°C

Storage Temperature Range .............................-65°C to +150°C

Junction Temperature......................................................+150°C

Lead Temperature (soldering, 10s) .................................+300°C

Passband Response

Stopband Attenuation A

Differential Gain dG

Differential Phase dθ

Signal-to-Noise Ratio SNR

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

f = 100kHz to 5MHz, relative to 100kHz

f ≥ 27MHz 39 43 dB

5-step modulated staircase

Peak signal (2V RMS noise, f = 100Hz to 50MHz

P-P

Channel without boost (see Table 2)

Channel with boost (see Table 2)

Gain = +6dB, +9.5dB

Gain = +12dB 0.25 0.90

Gain = +6dB, +9.5dB

Gain = +12dB 0.15 0.60

) to

Gain = +6dB, +9.5dB, +12dB

-0.75 +0.15 +0.75

+0.9 +1.2 +1.5

0.15 0.50

69 75 dB

Degrees

Channel without

Group Delay Deviation

Line-Time Distortion H

Field-Time Distortion V

Clamp Settling Time t

Output DC Clamp Level

Low-Frequency Gain Accuracy A

Low-Frequency Gain Matching A

∆t

DIST

CLAMP

V ( M ATC H )

Deviation from 100kHz

to 4.1MHz

18µs, 100 IRE bar 0.3 %

130 lines, 18µs, 100 IRE bar 0.5 %

To ±1% 100 Lines

SELECT = GND

SELECT = V

SELECT = floating

f = 100kHz, relative to a gain of +6dB -3 +3 %

Low-frequency channel-to-channel matching, f = 100kHz

boost (see Table 2)

Channel with boost (see Table 2)

Channel A 0.6 0.9 1.1

Channels B, C, D 1.1 1.5 1.8

Channels A, B, D 0.6 0.9 1.1

Channel C 1.25 1.6 1.95

Channels A, D 0.6 0.9 1.1

Channels B, C 1.1 1.5 1.8

11 20

17 30

MAX7445

4-Channel Video Reconstruction Filter

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(VCC= +5V ±5%, CL= 0 to 20pF, RL= 75Ω to GND for DC-coupled load, RL= 75Ω to VCC/ 2 for AC-coupled load, C

IN_

= 0.1µF,

GAIN = GND (+6dB) or V

(+9.5dB), TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at VCC= +5V, TA= +25°C.)

Group Delay Matching

Channel-to-Channel Crosstalk X

Output Short-Circuit Current I

Input Leakage Current I

Input Dynamic Swing for Gain of +6dB

SUPPLY

Supply Voltage Range V

Supply Current I

Power-Supply Rejection Ratio PSRR V

DISABLE

Output Impedance During Disable

D i sab l e Log i c- Inp ut H i g h V ol tag eV

D i sab l e Log i c- Inp ut Low V ol tag eV

Disable Logic Input Current I

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

g(MATCH)

DISABLEVIL

TALK

DISABLE

Low-frequency channel-to-channel matching, f = 100kHz

f = 100kHz to 3.58MHz 60 dB

OUT_ shorted to GND or V

SELECT = GND

SELECT = V

SELECT = floating

No load 100 140 mA

At 5MHz 2 kΩ

2ns

Channel A 1.2

Channels B, C, D 0.9

= 100mV

= 0V (sink), VIH = VCC (source) ±10 µA

, f = 0 to 3.5MHz 40 dB

P-P

Channels A, B, D 1.2

Channel C 0.9

Channels A, D 1.2

Channels B, C 0.9

4.75 5.25 V

2.0 V

70 mA

10 µA

0.8 V

P-P

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