MAX7454 [MAXIM]
HD/SD Switchable Video Filters and Buffers; HD / SD可切换的视频滤波器和缓冲器
| 型号： | MAX7454 |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | HD/SD Switchable Video Filters and Buffers |
| 文件： | 总8页 (文件大小：145K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-3482; Rev 0; 10/04
HD/S D S w it c h a b le Vid e o Filt e rs a n d Bu ffe rs
Ge n e ra l De s c rip t io n
Fe a t u re s
The MAX7454/MAX7455 triple-channel video recon-
struction filters and buffers are ideal for high definition
(HD), standard definition progressive scan/noninter-
laced (SDp), and standard definition interlaced (SDi)
television applications. These devices are a fully inte-
grated solution for filtering and buffering HD and/or
SDp/SDi TV signals in component video output format
♦ 30MHz High Definition (HD)/10MHz Standard
Definition (SD) Switchable Video Reconstruction
Filter
♦ 15% Magnitude Response Adjustment
♦ Passband: -2.3dB at 30MHz
-0.40dB at 10MHz
(Y P
P or RGB). The MAX7454/MAX7455 are compati-
R
B
-0.10dB at 5MHz
ble with the 1080i, 720p, 480p, and 480i scanning system
standards. In addition to having an HD/SD switchable
frequency response, the magnitude response can be
optimized by approximately 15% by a control input.
♦ Stopband: -55dB at 74MHz (HDTV)
-62dB at 27MHz (SDTV)
♦ Output Blank Level <1V for DC-Coupled Output
♦ +6dB Gain (MAX7454) or +12dB Gain (MAX7455)
♦ Direct Coupled Input, Zero Tilt
The input and output signals are DC-coupled to the
MAX7454/MAX7455, eliminating the large output AC-cou-
pling capacitors normally used. The MAX7454/MAX7455
♦ Direct Coupled Output, No Large Output Capacitor
output buffers drive a 2V
video signal into a standard
P-P
♦ Drives 2V
Signal in 150Ω Video Load
P-P
150Ω load. The MAX7454 has a gain of +6dB and the
MAX7455 has a gain of +12dB. Both devices are available
in a 20-pin TSSOP package and are fully specified over
the upper commercial (0°C to +85°C) temperature range.
♦ Small 20-Pin TSSOP Package
♦ Single +5V Supply
Ord e rin g In fo rm a t io n
Ap p lic a t io n s
TEMP
BUFFER
Set-Top Boxes
PART
PIN-PACKAGE
RANGE
GAIN (dB)
Direct-Broadcast Satellite (DBS) Receiver
DVD Players
MAX7454UUP
0°C to +85°C 20 TSSOP-EP**
+6
+6
MAX7454UUP+* 0°C to +85°C 20 TSSOP-EP**
MAX7455UUP* 0°C to +85°C 20 TSSOP-EP**
MAX7455UUP+* 0°C to +85°C 20 TSSOP-EP**
Hard-Disk Recorders
HDTV (LCD, PDP, DLP)
Professional Cameras
+12
+12
+Indicates lead-free packaging.
*Future product—contact factory for availability.
**EP = Exposed pad.
Pin Configuration appears at end of data sheet.
Typ ic a l Op e ra t in g Circ u it
+5V
V
CC
MAX7454/MAX7455
ENCODER
75Ω
SWITCHABLE
LOWPASS
FILTER
Y/R
OUT1
OUT2
OUT3
IN1
IN2
IN3
+6dB OR
+12dB
D/A
D/A
D/A
Z = 75Ω
O
75Ω
2
2
75Ω
75Ω
SWITCHABLE
LOWPASS
FILTER
Pb/G
Pr/B
+6dB OR
+12dB
Z
O
= 75Ω
75Ω
SWITCHABLE
LOWPASS
FILTER
+6dB OR
+12dB
Z
O
= 75Ω
75Ω
FSEL
SD/HD
GND
________________________________________________________________ Maxim Integrated Products
1
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.
HD/S D S w it c h a b le Vid e o Filt e rs a n d Bu ffe rs
ABSOLUTE MAXIMUM RATINGS
V
to GND..............................................................-0.3V to +6V
Maximum Current into IN1, IN2, IN3, SD/HD, FSEL .........±50mA
Operating Temperature Range
CC
IN1, IN2, IN3 to GND..................................-0.3V to (V + 0.3V)
CC
OUT1, OUT2, OUT3 to GND ......................-0.3V to (V + 0.3V)
CC
MAX745_UUP .....................................................0°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Junction Temperature ......................................................+150°C
SD/HD, FSEL to GND .................................-0.3V to (V + 0.3V)
CC
Continuous Power Dissipation (T = +70°C)
A
20-Pin TSSOP (derate 21.7mW/°C above +70°C) .....1739.1mW
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.
ELECTRICAL CHARACTERISTICS
(V = +5V ±5%, R
wise noted. Typical values are at V = +5V and T = +25°C.)
= 150Ω to GND, C
= 0 to 20pF to GND, SD/HD = GND, FSEL = V , T = T
to T
unless other-
CC
LOAD
LOAD
CC
A
MIN
MAX,
CC
A
PARAMETERS
SYMBOL
CONDITIONS
f = 100kHz to 26MHz, FSEL = GND
f = 100kHz to 26MHz, FSEL = V
MIN
TYP
-2.5
-1.7
-2.3
55
MAX
UNITS
-3.5
-2.6
-3.6
45
HD-Filter Passband Response
A
PB
dB
CC
f = 100kHz to 30MHz, FSEL = V
CC
HD-Filter Stopband Attenuation
SD-Filter Passband Response
SD-Filter Stopband Attenuation
A
SB
f = 74MHz, FSEL = GND
f = 10MHz, SD/HD = V , FSEL = V
dB
dB
dB
-0.65
50
-0.40
62
CC
CC
f = 27MHz, SD/HD = V , FSEL = GND
CC
100kHz to 26MHz, relative to 100kHz;
HD Group Delay Deviation
HD Group Delay Matching
∆t
5
0.1
2
ns
ns
G
FSEL = V
CC
Channel to channel, 100kHz to 2MHz;
FSEL = V
t
t
G(MATCH)
CC
100kHz to 5.75MHz, relative to 100kHz;
SD/HD = V , FSEL = V
CC
CC
SD Group Delay Deviation
∆t
ns
G
100kHz to 10MHz, relative to 100kHz;
12
2
SD/HD = V , FSEL = V
CC
CC
Channel to channel, 100kHz to 500kHz;
SD Group Delay Matching
Total Harmonic Distortion
ns
G(MATCH)
THD
FSEL = V
CC
Gain = +2V/V, V
= 2V video signal
P-P
OUT
-45
dB
100kHz to 26MHz
Differential Gain
Differential Phase
dG
5-step modulated staircase (Note 1)
5-step modulated staircase (Note 1)
0.3
0.2
%
dθ
Degrees
Output signal (2V ) to RMS noise (100kHz
P-P
to 30MHz)
Signal-to-Noise Ratio
Line Time Distortion
Input Voltage Range
SNR
62
67
±1
dB
mV
V
Deviations in a line with an 18µs, 100 IRE
bar (Note 2)
H
±3
DIST
MAX7454, THD > -30dB, f = 4.43MHz
0
1.2
0.6
IN
MAX7455, THD > -30dB, f = 4.43MHz
0
IN
SD/HD = V
-0.25
-0.25
+0.25
+0.25
±10
CC
MAX7454, V = 0.3V,
IN
FSEL = GND
Total Output DC Variation
Field Time Distortion
mV
mV
SD/HD = GND
V
DIST
130 lines, 18µs, 100 IRE bars
±1
2
_______________________________________________________________________________________
HD/S D S w it c h a b le Vid e o Filt e rs a n d Bu ffe rs
ELECTRICAL CHARACTERISTICS (continued)
(V = +5V ±5%, R
wise noted. Typical values are at V = +5V and T = +25°C.)
= 150Ω to GND, C
= 0 to 20pF to GND, SD/HD = GND, FSEL = V , T = T
to T
unless other-
CC
LOAD
LOAD
CC
A
MIN
MAX,
CC
A
PARAMETERS
Input Leakage Current
Input Capacitance
SYMBOL
CONDITIONS
MIN
TYP
±10
5
MAX
UNITS
nA
I
IN
C
pF
IN
Low-Frequency Gain Accuracy
f
= 100kHz
-2.5
2.4
+2.5
%
IN
f
= 100kHz, maximum difference between
IN
Low-Frequency Gain Matching
0
1.2
%
any two input channels
Dynamic Output Swing
THD > -30dB
V
P-P
Channel-to-Channel Isolation
DC to 1MHz
70
35
25
5
dB
V
IN
= 100mV at 5MHz
P-P
Power-Supply Rejection Ratio
PSRR
dB
V
IN
=10mV
at 26MHz
P-P
Supply Voltage Range
Supply Current
V
CC
4.75
2.4
5.25
235
V
I
CC
No load
220
mA
LOGIC INPUTS (SD/HD, FSEL)
Input High Voltage
Input Low Voltage
V
IH
V
V
V
IL
0.8
Input Current
Digital inputs = V or 0V
±10
µA
CC
Note 1: The differential gain and differential phase specifications apply to standard-definition composite video signals only.
Note 2: This applies for an anti-aliasing filtering application using a 0.1µF input capacitor. This does not apply for a video recon-
struction application, since there is no input-coupling capacitor.
Typ ic a l Op e ra t in g Ch a ra c t e ris t ic s
(R
= 150Ω to GND, V = +5V, and T = +25°C.)
CC A
LOAD
MAGNITUDE RESPONSE
(PASSBAND PLUS STOPBAND)
GROUP DELAY
10
0
100
90
80
70
60
50
40
30
20
10
0
-10
-20
-30
-40
-50
-60
-70
-80
HDHI
SDHI
SDHI
HDHI
SDLO
HDLO
0.1
1
10
100
1000
0.1
1
10
100
FREQUENCY (MHz)
FREQUENCY (MHz)
_______________________________________________________________________________________
3
HD/S D S w it c h a b le Vid e o Filt e rs a n d Bu ffe rs
Typ ic a l Op e ra t in g Ch a ra c t e ris t ic s (c o n t in u e d )
= 150Ω to GND, V = +5V, and T = +25°C.)
CC A
(R
LOAD
MODULATED 12.5T RESPONSE
(1 IRE = 7.14mV)
2T RESPONSE (1 IRE = 7.14mV)
MAX7454 toc04
MAX7454 toc03
200mV/div
200mV/div
200mV/div
200mV/div
400ns/div
200ns/div
DIFFERENTIAL GAIN
SUPPLY CURRENT vs. TEMPERATURE
0.2
0.1
0
0.30
0.28
0.26
0.24
0.22
0.20
0.18
0.16
0.14
0.12
0.10
-0.1
-0.2
HDHI
1
2
3
4
5
6
7
HDLO
DIFFERENTIAL PHASE
0.2
0.1
0
SDLO
-0.1
-0.2
1
2
3
4
5
6
7
-40
-15
10
35
60
85
TEMPERATURE (°C)
4
_______________________________________________________________________________________
HD/S D S w it c h a b le Vid e o Filt e rs a n d Bu ffe rs
P in De s c rip t io n
PIN
NAME
FUNCTION
1, 3, 5, 7, 11,
12, 15, 18
GND
Ground
2
4
6
IN1
IN2
IN3
Video Input 1
Video Input 2
Video Input 3
SD/HD Select. Selects between HD or SD magnitude response. Connect to GND to choose HD
bandwidth response.
8
9
SD/HD
Frequency Select. Selects either a low or high setting for both HD and SD frequency response (see
the Frequency Adjusting section).
FSEL
10, 13, 16,
19
+5V Power Supply. Bypass to GND with a 0.1µF capacitor. See the Power-Supply Bypassing and
Layout Considerations section.
V
CC
14
17
20
—
OUT3
OUT2
OUT1
EP
Video Output 3
Video Output 2
Video Output 1
Exposed Pad. The exposed pad is internally connected to ground.
Table 1. Frequency Selection Control
De t a ile d De s c rip t io n
The MAX7454/MAX7455 are ideal for use in consumer
electronic products such as HD-compatible cable-TV
set-top boxes or DBS receiver decoders, which process
vid e o s ig na ls in c omp one nt outp ut forma t. The
MAX7454/MAX7455 support both the 1080i and the
720p scanning formats for HDTV as well as the 480i and
480p formats for SDi and SDp TV. The reconstruction fil-
ters take three signals out of a video digital-to-analog
converter (DAC) or an encoder and smooth the signals
with appropriate filtering. FSEL and SD/HD select the fil-
ter frequency response for SDp, SDi, and HDTV (see
Table 1). The outputs are connected directly to standard
150Ω video loads.
MODE
HD Low
SD/HD
GND
FSEL
GND
HD High
SD Low
SD High
GND
V
CC
V
CC
GND
V
CC
V
CC
frequencies of 74MHz and above for HDTV (see the
Typical Operating Characteristics).
Frequency Adjusting
SD/HD selects the HD or SD mode. In HD or SD mode,
FSEL allows optimization of the passband or stopband
performance by adjusting the cutoff frequency. If pass-
band performance is the priority, set FSEL high for the
maximum passband performance with a small compro-
mise in stopband attenuation. If stopband performance
is more important, set FSEL low for the maximum stop-
band attenuation with a small compromise in passband.
The Typical Operating Circuit illustrates the internal
structure of the MAX7454/MAX7455. The lowpass filter
attenuates the high-frequency contents of the input,
and the output amplifier drives a standard video load.
Filt e r
Filter response
The video filter features an elliptic-type response with a
ste e p tra nsition ba nd re sponse to a c hie ve a wide r
passband response along with an excellent stopband
response. In addition, the filter has been optimized to
give a good time domain response with low overshoot.
The s top b a nd offe rs 62d B (typ ) of a tte nua tion a t
s a mp ling fre q ue nc ie s of 27MHz a nd a b ove for
SDTV a nd 55d B (typ ) of s top b a nd a tte nua tion for
Due to the s te e p tra ns ition b a nd re s p ons e , the
MAX7454/MAX7455 can be used in both progressive
scan and interlaced video signals. The stopband atten-
uation at 27MHz or higher is >62dB.
Ou t p u t Bu ffe r
The output buffer on the MAX7454/MAX7455 drives a
2V
signal into a 150Ω video load. It is intended to be
P-P
DC-coupled per the digital TV standard. No output AC-
_______________________________________________________________________________________
5
HD/S D S w it c h a b le Vid e o Filt e rs a n d Bu ffe rs
coupling capacitors are required when driving a cable,
thereby eliminating the normal adverse effects caused by
these large capacitors. The output DC level is controlled
to limit the DC voltage on the cable so the blanking level
of the video signal is always less than 1V, meeting the
digital TV specification. See the Output DC Level section
for more information.
Ou t p u t Co n s id e ra t io n s
The outputs of the MAX7454/MAX7455 are normally
DC-coupled. No AC-coupling capacitors are required.
The MAX7454/MAX7455 connect directly to the video
cable with a 75Ω series termination resistor. The other
end of the cable should also be properly terminated
with a 75Ω resistor. Because of the inherent divide-by-
two of this configuration the peak-to-peak amplitude as
well as the DC level of the signal are divided by two.
The biasing on the output of the MAX7454/MAX7455 is
such that the blanking level of the video signal on the
cable is always less than 1V, which complies with digi-
tal TV requirements.
The output of the MAX7454/MAX7455 can also be AC-
coupled when driving a high-impedance load. In anti-
aliasing applications, when the optimum bias point for
the converter needs to be established, the MAX7454/
MAX7455 c a n d rive a hig h imp e d a nc e (typ >1kΩ)
through an AC-coupling capacitor.
An t i-Alia s in g Filt e r
The MAX7454/MAX7455 can be used as an anti-alias-
ing filter to eliminate out-of-band noise in an analog-to-
d ig ita l vid e o-s a mp ling s ys te m. The outp ut of the
MAX7454/MAX7455 can be DC- or AC-coupled. This
decision depends on the input range of the analog-to-
d ig ita l c onve rte r a nd the re q uire d a c c ura c y of the
resulting digital blanking level. The output blanking
level of the MAX7454/MAX7455 is 1.4V with the nega-
tive peak of the signal at 0.8V and the positive peak
Gain Options
The MAX7454 features an overall gain of +6dB, while
the MAX7455 features an overall gain of +12dB.
Output DC Level
The MAX7454/MAX7455 are DC-coupled circuits. The
nominal DC or nominal instantaneous AC voltage on
the outputs of the MAX7454/MAX7455 can be deter-
mined by the following equations:
V
OUT
= 2 x V + 0.8V (MAX7454)
IN
white at 2.8V. This assumes a 1V
input signal with
P-P
V
OUT
= 4 x V + 0.8V (MAX7455)
IN
the ne g a tive p e a k a t 0V. Se e the Ele c tric a l
Characteristics table for the specified variations of
these values. If the DC and peak levels are not compat-
ible with the data-converter input, the outputs of the
MAX7454/MAX7455 need to be AC-coupled. Choose
an AC-coupling capacitor value that ensures that the
lowest frequency content in the video signal is passed
and the line time distortion is kept within desired limits.
The resulting capacitor value is dependent on the input
impedance of the converter circuit. Use a video clamp
to re-establish the DC level.
For example, in the MAX7454, 0V on the input results in
an output nominal voltage of 0.8V, and a 0.3V input
(typical blanking level) results in an output nominal
level of 1.4V.
Ap p lic a t io n s In fo rm a t io n
In p u t Co n s id e ra t io n s
The inputs on the MAX7454/MAX7455 are normally DC-
c oup le d . Thus , no AC-c oup ling c a p a c itors a re
required. The input voltage range includes ground and
typically extends up to 1.2V. If the input is from a typi-
cal single supply current output DAC or encoder it can
be connected directly to the MAX7454/MAX7455. The
board trace should be kept as short as possible to min-
imize the parasitic stray capacitance. The MAX7454/
MAX7455 contribute 5pF of capacitance. For example,
a total capacitance on the input of approximately 20pF
causes a 100MHz pole if the DAC termination resistor is
75Ω. A pole at 100MHz introduces an additional 0.5dB
passband attenuation at 30MHz.
P o w e r-S u p p ly Byp a s s in g a n d La yo u t
Co n s id e ra t io n s
The MAX7454/MAX7455 operate from a single +5V
supply. Bypass each V to GND with a 0.1µF capaci-
CC
tor and an additional 1µF capacitor in parallel if any sig-
nificant low-frequency disturbances are present in the
vicinity of the MAX7454/MAX7455. Use an extensive
ground plane to ensure optimum performance. The
three V
pins (pins 13, 16, and 19) that supply the
CC
individual channels can be connected together and
bypassed as one, provided the components are close
The input to the MAX7454/MAX7455 can be AC-cou-
pled. In this case, it is important to set the DC bias
properly to ensure that the negative peak of the video
signal is as near to zero volts as possible. The bias can
be fixed or a video clamp can be used. A video clamp
is preferable because it limits the total swing of the sig-
nal by holding the blanking level of the signal constant.
to the pins. Bypass the remaining V
pin (pin 10)
CC
separately with the same 0.1µF and 1µF capacitor com-
bination.
Place the input and output termination resistors as close
to the device as possible. Alternatively, the terminations
may be placed further from the device if the PC board
6
_______________________________________________________________________________________
HD/S D S w it c h a b le Vid e o Filt e rs a n d Bu ffe rs
traces are designed to be a controlled impedance of
75Ω. Regardless, the parasitic capacitance should be
kept as low as possible to avoid performance degrada-
tion in the frequency response at 30MHz.
One tested board is a 4-layer board using FR-4 materi-
al and 1oz copper. It has equal areas of metal on the
top side and bottom side that coincide with the plastic
encapsulated area of the 20-pin TSSOP package. The
two middle layers are power and ground planes. The
board has 21 15-mil plated-through via holes between
the top, bottom, and ground plane layers. This board
was measured and has a total thermal resistance of
25°C/W, less than the 30°C/W goal.
Refer to the MAX7454/MAX7455 evaluation kit for a
proven PC board layout.
Ex p o s e d P a d a n d He a t Dis s ip a t io n
The TSSOP package of the MAX7454/MAX7455 has an
exposed pad on its bottom. This pad is electrically con-
nected to GND. Do not route signals under the package.
P in Co n fig u ra t io n
He a t d is p e rs ion is a ve ry imp orta nt is s ue for the
MAX7454/MAX7455. The design of the PC board area
a ssoc ia te d with a nd in the vic inity of the de vic e is
important in achieving an adequate thermal resistance
to keep the temperature of the MAX7454/MAX7455
within the specified limits.
TOP VIEW
GND
IN1
1
2
20 OUT1
19
V
CC
GND
IN2
3
18 GND
17 OUT2
The thermal resistance of the 20-pin TSSOP package is
60°C/W from die to ambient in free air. The thermal resis-
tance from the die to the package surface (case) is
2°C/W. The net thermal resistance on a practical board
is between these two numbers. The typical power dissi-
pation of the MAX7454/MAX7455 is 1.2W. To keep the
die temperature within specified limits, the maximum net
thermal resistance should not exceed 30°C/W. This value
is calculated assuming a worst-case ambient tempera-
ture of +85°C and the maximum die temperature.
4
MAX7454
MAX7455
GND
IN3
5
16
V
CC
6
15 GND
GND
SD/HD
FSEL
7
14
13
OUT3
8
V
CC
9
12 GND
11 GND
V
CC
10
The use of a 2-layer board with a good ground plane is
re c omme nd e d . Pla c e c op p e r d ire c tly und e r the
MAX7454/MAX7455 package so that it matches the
outline of the plastic encapsulated area. Place via holes
in this area to electrically and thermally connect it to the
ground plane. Use as many vias as possible for maxi-
mum heat transfer.
TSSOP
Ch ip In fo rm a t io n
TRANSISTOR COUNT: 19191
PROCESS: BiCMOS
_______________________________________________________________________________________
7
HD/S D S w it c h a b le Vid e o Filt e rs a n d Bu ffe rs
P a c k a g e In fo rm a t io n
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages.)
XX XX
PACKAGE OUTLINE, TSSOP, 4.40 MM BODY,
EXPOSED PAD
1
E
21-0108
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.
8 _____________________Ma x im In t e g ra t e d P ro d u c t s , 1 2 0 S a n Ga b rie l Drive , S u n n yva le , CA 9 4 0 8 6 4 0 8 -7 3 7 -7 6 0 0
© 2004 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
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