MAX7444ESA+T Maxim Integrated Products, MAX7444ESA+T Datasheet - Page 4

• Manufacturer Part Number: MAX7444ESA+T
• Description: IC FILTER RECON VID 8-SOIC
• Manufacturer: Maxim Integrated Products

Specifications of MAX7444ESA+T

• Filter Type: Low Pass
• Frequency - Cutoff Or Center: 27MHz
• Number Of Filters: 2
• Voltage - Supply: 4.75 V ~ 5.25 V
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width) Exposed Pad, 8-eSOIC. 8-HSOIC
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Max-order: -

The primary function of the MAX7443/MAX7444 is to fil-
ter and buffer the encoder DAC outputs that contain
digital video information in applications such as set-top
boxes, hard-disk recorders, DVD players, and digital
VCRs. These devices reconstruct and clean up analog
video signals. Each MAX7443/MAX7444 consists of a
lowpass filter and an adjustable-gain output video
buffer that is capable of driving two standard 150Ω
video loads. The luma (YIN) and chroma (CIN) video
inputs are summed internally to provide the composite
(CVOUT) video output.
Triple-Channel Video Reconstruction Filter and
Buffer for Composite and Y/C Outputs
4
(V
CC
PIN
90
85
80
75
70
65
_______________________________________________________________________________________
1
2
3
4
5
6
7
8
= +5V, T
-40
-15
CVOUT
NAME
COUT
GSET
YOUT
A
GND
V
CIN
YIN
vs. TEMPERATURE
SUPPLY CURRENT
CC
= +25°C, unless otherwise noted.)
TEMPERATURE (°C)
10
Luma (Y) Input
Gain-Setting Control Input. See Table 1
for values.
Chroma (C) Input
Ground
5V Power Supply
Chroma (C) Output
Composite Video Output
Luma (Y) Output
Detailed Description
35
60
Pin Description
FUNCTION
85
Typical Operating Characteristics (continued)
-0.1
-0.2
-0.3
-0.1
-0.2
-0.3
0.3
0.2
0.1
0.3
0.2
0.1
0
0
1
1
2
2
DIFFERENTIAL PHASE
DIFFERENTIAL GAIN
3
3
4
4
These devices operate from a single +5V supply. The
filters have a nominal cutoff frequency optimized for
NTSC, PAL, and SDTV.
The reconstruction filter consists of two 2nd-order
Sallen-Key stages. The Butterworth-type response fea-
tures a maximally flat passband for NTSC and PAL
bandwidths. The stopband offers 41dB (typ) of attenua-
tion at sampling frequencies of 27MHz and above (see
Typical Operating Characteristics).
The high-frequency boost available in the MAX7444
compensates for signal degradation and rolloff in the
video encoder, which increases the image sharpness.
The MAX7443 has a flat response over the video band-
width.
The output buffer drives two 150Ω video loads with a
2V
provides a gain of 6dB, 9.5dB, and 12dB, which are
selected by tying the GSET pin to GND, V
ing, respectively. The MAX7443/MAX7444 can drive an
AC load or drive the video load directly without using
the large output capacitor. The output buffer drives a
DC load with an output blanking level of less than 1V.
P-P
5
5
signal. The adjustable gain of the output buffer
6
6
7
7
200mV/div
200mV/div
YOUT
YIN
MULTIBURST RESPONSE
High-Frequency Boost
10µs/div
Output Buffer
Filter Response
CC
, or float-
Filter