MAX4029EWP+T [MAXIM]
Video Multiplexer, 4 Func, 1 Channel, BIPolar, PDSO20, 0.300 INCH, MS-013, SOIC-20;
| 型号： | MAX4029EWP+T |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Video Multiplexer, 4 Func, 1 Channel, BIPolar, PDSO20, 0.300 INCH, MS-013, SOIC-20 光电二极管 |
| 文件： | 总12页 (文件大小：978K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
EVALUATION KIT AVAILABLE
MAX4028/MAX4029
Triple/Quad, 2:1 Video
Multiplexer-Amplifiers with Input Clamps
General Description
Features
● Single +5V Operation
The MAX4028/MAX4029 are 5V, triple/quad, 2:1 voltage-
feedback multiplexer-amplifiers with input clamps and a
fixed gain of +2V/V (6dB). Channel 1 (IN1A and IN1B)
inputs are clamped to the video sync tip of the input
signal, while the remaining inputs can be clamped to
either the video sync tip or the video sync of channel 1
(IN1_). The latter is referred to as a key clamp and is pin
selectable. Selectable clamp/key-clamp inputs and fixed-
gain video output buffers make the MAX4028/MAX4029
ideal for video-source switching applications such as
entertainment systems, video projectors, and displays/
TVs. Both devices have 20ns channel switching times
and low ±10mVP-P switching transients, making them
ideal for high-speed video switching applications such as
on-screen display (OSD) insertion.
● Independently Selectable Sync-Tip or
Key-Clamp Inputs
● Adjustable Key-Clamp Voltage
● 130MHz Large-Signal -3dB Bandwidth
● 210MHz Small-Signal -3dB Bandwidth
● 300V/µs Slew Rate
● 20ns Switching Time
● Ultra-Low ±10mV
Switching Transient
P-P
● 0.2% Differential Gain/0.4° Phase Error
● Low-Power, High-Impedance Disable Mode
Ordering Information
The MAX4028/MAX4029 have a -3dB large-signal (2V
)
P-P
PART
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
16 TSSOP
bandwidth of 130MHz, a -3dB small-signal bandwidth of
210MHz, and a 300V/µs slew rate. Low differential gain
and phase errors of 0.2% and 0.4°, respectively, make
these devices ideal for broadcast video applications.
MAX4028EUE
MAX4028EWE
MAX4029EUP
MAX4029EWP
16 Wide SO
20 TSSOP
20 Wide SO
The MAX4028/MAX4029 are specified over the -40°C to
+85°C extended temperature range and are offered in
16-pin and 20-pin TSSOP/SO packages.
Typical Operating Circuit
A/B
+5V
Applications
● Blade Servers
● Security Systems
● Video Projectors
● Displays and Digital Televisions
● Broadcast and Graphics Video
● Set-Top Boxes
C
IN
0.1µF
V
CC
75Ω CABLE
MAX4028
MAX4029
IN1A
CLAMP
0.1µF
0.01µF
75Ω
75Ω CABLE
C
IN
75Ω
OUT1
0.1µF
75Ω CABLE
IN1B
CLAMP
1kΩ
75Ω
1kΩ
C
0.1µF
● Notebook Computers
● Video Crosspoint Switching
IN
75Ω CABLE
IN2A
CLAMP
75Ω
75Ω CABLE
75Ω
OUT2
C
IN
0.1µF
Selector Guide
75Ω CABLE
IN2B
CLAMP
1kΩ
NO. OF 2:1
MUX-AMPS
PART
GAIN
75Ω
1kΩ
DISABLE
MAX4028
MAX4029
3
4
2V/V
2V/V
KEYREF
R
KEYREF
6kΩ
KEY/CLAMP
CONTROL
CLAMP/KEY_2
Pin Configurations appear at end of data sheet.
19-3240; Rev 1; 4/15
MAX4028/MAX4029
Triple/Quad, 2:1 Video
Multiplexer-Amplifiers with Input Clamps
Absolute Maximum Ratings
Supply Voltage (V
to GND).................................-0.3V to +6V
20-Pin TSSOP (derate 11mW/°C above +70°C).........879mW
20-Pin Wide SO (derate 10mW/°C above +70°C) ......800mW
Operating Temperature Range........................... -40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range............................ -65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
CC
IN_A, IN_B, OUT_.................................... -0.3V to (V
DISABLE, A/B, KEYREF, CLAMP/KEY_.. -0.3V to (V
Current Into IN_A, IN_B ..................................................±0.5mA
+ 0.3V)
+ 0.3V)
CC
CC
Short-Circuit Duration (V
Short-Circuit Duration (V
to GND)......................Continuous
OUT
OUT
to V ) ...........................(Note 1)
CC
Continuous Power Dissipation (T = +70°C)
A
16-Pin TSSOP (derate 9.4mW/°C above +70°C)........755mW
16-Pin Wide SO (derate 9.5mW/°C above +70°C) .....762mW
Note 1: Do not short V
to V
.
OUT
CC
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.
DC Electrical Characteristics
(V = +5V, GND = 0V, R = 150Ω to GND, V
= +5V, R
= 6kΩ, C = 0.1µF to GND, T = T
to T
, unless otherwise
CC
L
DISABLE
KEYREF
IN
A
MIN
MAX
noted. Typical values are at T = +25°C.) (Note 2)
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
5.5
40
UNITS
Operating Supply Voltage Range
V
Guaranteed by PSRR
MAX4028, R = ∞
4.5
V
CC
29
38
9
L
Quiescent Supply Current
Disable Supply Current
Output Clamp Voltage
I
mA
mA
V
CC
MAX4029, R = ∞
55
L
MAX4028
MAX4029
15
V
= 0V
DISABLE
11
0.4
1.1
5
20
Clamp (Note 3)
0.32
0.48
V
CLAMP
Key clamp (Note 4)
Input Clamping Current
Clamp Voltage Matching
Clamp Voltage Drift
I
Input voltage = input clamp + 0.5V
Measured at output
18
µA
mV
µV/°C
MΩ
Ω
IN
∆V
10
80
7
CLAMP
TC
Measured at output
VCLAMP
Input Resistance
R
IN
Output Resistance
R
0.7
2
OUT
OUT
Disable Output Resistance
Power-Supply Rejection Ratio
Voltage Gain
R
V
= 0V
kΩ
DISABLE
4.5V < V
PSRR
< 5.5V (Note 5)
48
58
2.0
±1
dB
CC
A
1.9
2.1
±2
V/V
%
VCL
Channel-to-Channel Gain Matching
∆A
VCL
V
CLAMP
+ 2.4
Output-Voltage High
V
V
OH
Output-Voltage Low
Output Current
V
V
V
OL
CLAMP
0.8
I
30
mA
OUT
LOGIC INPUT CHARACTERISTICS (DISABLE , A/B, CLAMP/KEY_)
Logic-Low Threshold
Logic-High Threshold
Logic-Low Input Current
Logic-High Input Current
V
V
V
IL
IH
IL
V
2.0
I
V
V
= 0V
6.6
1.2
25
25
µA
µA
IL
I
= V
CC
IH
IH
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MAX4028/MAX4029
Triple/Quad, 2:1 Video
Multiplexer-Amplifiers with Input Clamps
AC Electrical Characteristics
(V
= +5V, GND = 0V, R = 150Ω to GND, V
= +5V, R
= 6kΩ, C = 0.1µF, T = T
to T
, unless otherwise noted.
CC
L
DISABLE
KEYREF
IN
A
MIN
MAX
Typical values are at T = +25°C.)
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
210
130
MAX
UNITS
MHz
Small-Signal -3dB Bandwidth
Large-Signal -3dB Bandwidth
BW
BW
V
V
= 100mV
P-P
SS
OUT
= 2V
MHz
LS
OUT
P-P
Small-Signal 0.1dB Gain Flatness
Bandwidth
BW
V
V
= 100mV
P-P
30
30
MHz
MHz
0.1dBSS
OUT
Large-Signal 0.1dB Gain Flatness
Bandwidth
BW
= 2V
= 2V
0.1dBLS
SR
OUT
P-P
Slew Rate
V
V
300
20
V/µs
ns
OUT
P-P
Settling Time to 0.1%
Power-Supply Rejection Ratio
Output Impedance
Differential Gain Error
Differential Phase Error
Group Delay
t
= 2V step
S
OUT
PSRR
f = 100kHz
55
dB
Z
f = 100kHz
0.7
0.2
0.4
1.0
70
Ω
O
DG
DP
5-step modulated staircase
5-step modulated staircase
f = 3.58MHz or 4.43MHz
100kHz to 30MHz
f = 100kHz
%
degrees
ns
D/dT
SNR
Peak Signal to RMS Noise
Channel-to-Channel Crosstalk
A/B Crosstalk
dB
X
73
dB
TALK
X
f = 100kHz
91
dB
TALKAB
Off-Isolation
A
V
OUT_
= 2V , f = 100kHz
108
dB
ISO
P-P
Droop
D
Guaranteed by input clamp current
2
%
R
SWITCHING CHARACTERISTICS
Channel Switching Time
Enable Time
t
20
0.1
0.1
±10
ns
µs
µs
SW
t
ON
Disable Time
t
OFF
Switching Transient
mV
P-P
Note 2: All devices are 100% production tested at T = +25°C. Specifications over temperature are guaranteed by design.
A
Note 3: The clamp voltage at the input is V
(measured at the output) divided by gain + V
.
CLAMP
BE
Note 4: The key-clamp voltage is above the sync-tip clamp voltage by approximately 0.7V, and is adjusted by varying R
.
KEYREF
Note 5: Measured at f = 100Hz at thermal equilibrium.
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MAX4028/MAX4029
Triple/Quad, 2:1 Video
Multiplexer-Amplifiers with Input Clamps
Typical Operating Characteristics
(V
= +5V, GND = 0V, V
= +5V, R = 150Ω to GND, C = 0.1µF, R
= 6.04kΩ ±1%, T = +25°C, unless otherwise
CC
DISABLE
L
IN
KEYREF
A
noted.)
SMALL-SIGNAL BANDWIDTH
vs. FREQUENCY
SMALL-SIGNAL GAIN FLATNESS
vs. FREQUENCY
LARGE-SIGNAL BANDWIDTH
vs. FREQUENCY
8
6.2
6.1
6.0
5.9
5.8
5.7
5.6
5.5
5.4
5.3
5.2
8
V
= 100mV
V
= 100mV
V
OUT
= 2V
P-P
OUT
P-P
OUT
P-P
7
6
7
6
5
5
4
4
3
3
2
2
1
1
0
0
-1
-2
-1
-2
100k
1M
10M
FREQUENCY (Hz)
100M
1G
1G
1G
100k
1M
10M
FREQUENCY (Hz)
100M
1G
100k
1M
10M
FREQUENCY (Hz)
100M
1G
LARGE-SIGNAL GAIN FLATNESS
vs. FREQUENCY
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
DIFFERENTIAL GAIN AND PHASE
0.3
0
-10
-20
-30
-40
-50
-60
-70
6.2
6.1
6.0
5.9
5.8
5.7
5.6
5.5
5.4
5.3
5.2
V
= 2V
0.2
0.1
0
OUT
P-P
-0.1
-0.2
-0.3
6th
1st
2nd
3rd
4th
5th
0.06
0.04
0.02
0
-0.02
-0.04
-0.06
6th
1st
2nd
3rd
4th
5th
100k
1M
10M
FREQUENCY (Hz)
100M
1k
10k 100k
1M
10M 100M 1G
FREQUENCY (Hz)
OFF-ISOLATION
vs. FREQUENCY
ALL-HOSTILE CROSSTALK (CHANNEL TO
CHANNEL) vs. FREQUENCY
ALL-HOSTILE CROSSTALK (A TO B ON ANY
CHANNEL) vs. FREQUENCY
0
0
-20
0
-10
-20
-30
-40
-50
-60
-70
-80
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
-40
-60
-80
-100
-120
-140
10k
100k
1M
FREQUENCY (Hz)
10M
100M
1G
100k
1M
10M
100M
1G
100k
1M
10M
100M
FREQUENCY (Hz)
FREQUENCY (Hz)
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MAX4028/MAX4029
Triple/Quad, 2:1 Video
Multiplexer-Amplifiers with Input Clamps
Typical Operating Characteristics (continued)
(V
= +5V, GND = 0V, V
= +5V, R = 150Ω to GND, C = 0.1µF, R
= 6.04kΩ ±1%, T = +25°C, unless otherwise
CC
DISABLE
L
IN
KEYREF
A
noted.)
INPUT-VOLTAGE NOISE DENSITY
vs. FREQUENCY
OUTPUT IMPEDANCE
vs. FREQUENCY
LARGE-SIGNAL TRANSIENT RESPONSE
MAX4028 toc12
100
10
1
1000
100
10
V
IN
1.6VDC
500mV/div
V
OUT
1V/div
0.1
1
10ns/div
10k
100k
1M
10M
100M
1G
1
10
100
1k
10k 100k
1M
FREQUENCY (Hz)
FREQUENCY (Hz)
CHANNEL-SWITCHING TIME
(CHA = 1.5VDC, CHB = 1VDC)
SMALL-SIGNAL TRANSIENT RESPONSE
CHANNEL-SWITCHING TRANSIENT
MAX4028 toc14
MAX4028 toc15
MAX4028 toc13
5VDC
0VDC
5VD
0VD
A/B
2.5V/div
V
A/B
2.5V/div
IN
1.6VDC
25mV/div
V
SIGNAL 2
50mV/div
V
OUT
OUT
500mV/div
20mV/div
20ns/div
10ns/div
20ns/div
OPTIMAL ISOLATION RESISTANCE
vs. CAPACITIVE LOAD
SMALL-SIGNAL BANDWIDTH
vs. FREQUENCY
ENABLE RESPONSE TIME
(V
= 0.5V)
OUT
30
25
20
15
10
5
11
10
9
MAX4028 toc16
C
= 15pF
LOAD
5VDC
0VDC
0.5VDC
0VDC
ENABLE
2.5V/div
C
= 10pF
LOAD
8
7
6
5
4
C
= 5pF
LOAD
V
OUT
3
250mV/div
2
0
1
0
50
100
C
150
(pF)
200
250
100k
1M
10M
FREQUENCY (Hz)
100M
1G
50ns/div
LOAD
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MAX4028/MAX4029
Triple/Quad, 2:1 Video
Multiplexer-Amplifiers with Input Clamps
Typical Operating Characteristics (continued)
(V
= +5V, GND = 0V, V
= +5V, R = 150Ω to GND, C = 0.1µF, R
= 6.04kΩ ±1%, T = +25°C, unless otherwise
CC
DISABLE
L
IN
KEYREF
A
noted.)
KEY-CLAMP REFERENCE VOLTAGE
CLAMP VOLTAGE
vs. TEMPERATURE
vs. R
KEYREF
0.43
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
0.42
0.41
0.40
0.39
0.38
0.37
-50
-25
0
25
50
75
100
1
3
5
7
9
11
13
TEMPERATURE (°C)
R
(kΩ)
KEYREF
Pin Description
PIN
NAME
FUNCTION
MAX4028
MAX4029
—
1
1
2
3
4
IN4A
IN3A
IN2A
IN1A
Amplifier Input 4A
Amplifier Input 3A
Amplifier Input 2A
Amplifier Input 1A
2
3
Channel-Select Input. Drive A/B high or leave unconnected to select channel A.
Drive A/B low to select channel B.
4
5
5
6
A/B
Key-Clamp Reference Output. Connect an external resistor from KEYREF to GND to
generate the key-clamp voltage.
KEYREF
6
7
7
8
IN1B
IN2B
IN3B
IN4B
OUT4
Amplifier Input 1B
Amplifier Input 2B
Amplifier Input 3B
Amplifier Input 4B
Amplifier Output 4
8
9
—
—
10
11
Output 3 Clamp or Key-Clamp Input. Drive CLAMP/KEY_3 high to clamp OUT3.
Drive CLAMP/KEY_3 low to key clamp OUT3.
9
12
CLAMP/KEY_3
10
11
13
14
GND
Ground
OUT3
Amplifier Output 3
Output 2 Clamp or Key-Clamp Input. Drive CLAMP/KEY_2 high to clamp OUT2.
Drive CLAMP/KEY_2 low to key clamp OUT2.
12
13
14
15
16
17
CLAMP/KEY_2
OUT2
Amplifier Output 2
Power-Supply Voltage. Bypass VCC to GND with 0.1µF and 0.01µF capacitors as
close as possible to the pin.
VCC
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MAX4028/MAX4029
Triple/Quad, 2:1 Video
Multiplexer-Amplifiers with Input Clamps
Pin Description (continued)
PIN
NAME
FUNCTION
MAX4028
MAX4029
15
18
OUT1
Amplifier Output 1
Disable Input. Pull DISABLE high for normal operation. Drive DISABLE low to disable
16
—
19
20
DISABLE
all outputs.
Output 4 Clamp or Key-Clamp Input. Drive CLAMP/KEY_4 high to clamp OUT4.
Drive CLAMP/KEY_4 low to key clamp OUT4.
CLAMP/KEY_4
Detailed Description
V
CC
The MAX4028/MAX4029 are 5V, triple/quad, 2:1
voltage-feedback multiplexer-amplifiers with input clamps
and a fixed gain of +2V/V (6dB). Channel 1 (IN1A and
IN1A
IN1B
CLAMP
CLAMP
IN1B) inputs are clamped to the video sync tip of the
OUT1
input IN1_ channel, while the remaining inputs can be
clamped to either the video sync tip of the respective input
channel (IN_A and IN_B) or the video sync of channel 1
(IN1_). The latter is referred to as a key clamp and is pin
selectable. Selectable clamp/key-clamp inputs and fixed-
gain video output buffers make the MAX4028/MAX4029
ideal for video-source switching applications such as
entertainment systems, video projectors, and displays/
TVs. Both devices have 20ns channel switching times
1kΩ
1kΩ
IN2A
IN2B
CLAMP/
KEY
CLAMP
OUT2
1kΩ
CLAMP/
KEY
CLAMP
and low ±10mV
ideal for both high-speed video switching applications
such as OSD insertion.
switching transients, making them
1kΩ
P-P
CLAMP/KEY_2
IN3A
CLAMP/
KEY
CLAMP
The MAX4028/MAX4029 have a -3dB large-signal (2V
)
P-P
OUT3
bandwidth of 130MHz, a -3dB small-signal bandwidth of
210MHz, and a 300V/µs slew rate. Low differential gain
and phase errors of 0.2% and 0.4°, respectively, make
these devices ideal for broadcast video applications.
IN3B
1kΩ
CLAMP/
KEY
CLAMP
1kΩ
CLAMP/KEY_3
A/B
Sync Tip and Key Clamps
IN4A
The MAX4028/MAX4029 have AC-coupled inputs, with
either a sync tip or key clamp to provide bias for the video
signal. Channel 1 of the MAX4028/MAX4029 always has a
sync tip clamp at the input, while the remaining channels
are selectable as either sync tip or key clamps to accom-
modate the various video waveforms (see the Clamp/
Key-Clamp Settings for Video Formats section). The value
of the sync-tip clamp voltage is set internally for the low-
est value, consistent with linear operation, and cannot be
adjusted. The key-clamp voltage is adjustable, to compen-
sate for variations in the voltage between component video
inputs such as Linear RGB, YPbPr, and Y-C, by varying
CLAMP/
KEY
CLAMP
OUT4
IN4B
1kΩ
CLAMP/
KEY
CLAMP
1kΩ
CLAMP/KEY_4
CLAMP
VOLTAGE
DISABLE
KEYREF
MAX4029
GND
Figure 1. MAX4029 Functional Diagram
R . The key-clamp voltage can be computed from:
KEYREF
V
= 0.40 + 2000/[(5000 x R
)/
Key-Clamp
KEYREF
(5000 + R
)]
KEYREF
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MAX4028/MAX4029
Triple/Quad, 2:1 Video
Multiplexer-Amplifiers with Input Clamps
Therefore, a 6kΩ resistor will produce a 1.13V
key-clamp voltage as shown in Figure 2. The clamp
ground. The clamps used here are active devices with the
coupling capacitor serving two functions; first, as a charge
reservoir to maintain the clamp voltage, and second, as
the compensation capacitor for the clamp itself. If an input
is not used, it must be terminated to avoid causing oscilla-
tions that could couple with another input.
voltage (V
) is measured at the output; the voltage
CLAMP
at the input is V
the gain (+2V/V) + V
(sync tip or key clamp) divided by
.
CLAMP
BE
In order for these clamps (sync tip or key) to work
properly, the input must be coupled with a 0.1µF capac-
itor (typ) with low leakage (<1µA to 2µA, max). Without
proper coupling, the clamp voltage will change during the
horizontal line time causing the “black level” to vary, chang-
ing the image brightness from left to right on the display. In
addition to the capacitor, a low resistance (≤ 75Ω) is
required on the source side to return the capacitor to
In general, a sync-tip clamp is used for composite video
(Cvbs), gamma-corrected primaries (R’G’B’), and the
luma signal (Y) in S-video. A key clamp is preferred for
component color difference signals (Pb and Pr), linear
primaries (RGB in PCs), and chroma (C) in S-video. The
rule is to sync tip clamp a signal if sync is present and
key clamp all others. Several examples are given in the
Clamp/Key-Clamp Settings for Video Formats section.
KEY-CLAMP REFERENCE VOLTAGE
vs. R
Clamp/Key-Clamp Settings for Video Formats
KEYREF
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
Tables 1 and 2 provide the clamp settings on the MAX4028/
MAX4029 to interface with various video formats.
Low-Power, High-Impedance Disable Mode
All parts feature a low-power, high-impedance disable
mode that is activated by driving the DISABLE input
low. Placing the amplifier in disable mode reduces
the quiescent supply current and places the output
impedance at 2kΩ typically. Multiple devices can be
paralleled to construct larger switch matrices by
connecting the outputs of several devices together
and disabling all but one of the paralleled amplifiers’
outputs.
1
3
5
7
9
11
13
R
(kΩ)
KEYREF
Figure 2. Key-Clamp Reference Voltage vs. R
KEYREF
Table 1. MAX4028 Clamp Settings for Video Formats
INPUT
FORMAT
CLAMP/KEY
INPUT
FORMAT
CLAMP/KEY
Clamp
1
2
3
Cvbs1
Clamp
1
2
3
Y
C
Cvbs2
Clamp
Key
Cvbs3
Clamp
Cvbs
Clamp
INPUT
FORMAT
CLAMP/KEY
Clamp
INPUT
FORMAT
CLAMP/KEY
Clamp
Key
1
2
3
G’
B’
R’
1
2
3
Y
Clamp
Pb
Pr
Clamp
Key
R, G, B have sync on all.
INPUT
FORMAT
CLAMP/KEY
Clamp
Key
1
2
3
Gs
B
R
Key
Gs, B, R have sync only on Green.
Maxim Integrated
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MAX4028/MAX4029
Triple/Quad, 2:1 Video
Multiplexer-Amplifiers with Input Clamps
Table 2. MAX4029 Clamp Settings for Video Formats
INPUT
FORMAT
Cvbs1
CLAMP/KEY
Clamp
INPUT
FORMAT
CLAMP/KEY
Clamp
Key
1
2
3
4
1
2
3
4
Gs
R
Cvbs2
Clamp
Cvbs3
Clamp
B
Key
Cvbs4
Clamp
Cvbs
Clamp
Gs, B, R have sync only on Green.
INPUT
FORMAT
CLAMP/KEY
Clamp
Key
INPUT
FORMAT
CLAMP/KEY
Clamp
Key
1
2
3
4
H-Sync
1
2
3
4
Y
Pr
G
B
R
Key
Pb
Key
Key
Cvbs
Clamp
R, G, B have sync on none.
INPUT
FORMAT
CLAMP/KEY
Clamp
INPUT
FORMAT
CLAMP/KEY
Clamp
1
2
3
4
Y
1
2
3
4
Cvbs
G’
C
Key
Clamp
Cvbs
Cvbs
Clamp
B’
Clamp
Clamp
R’
Clamp
R, G, B have sync on all.
The MAX4028/MAX4029 have a fixed gain of +2V/V
that is internally set with two 1kΩ thin-film resistors. The
impedance of the internal feedback resistors must be
taken into account when operating multiple MAX4028/
MAX4029s in large multiplexer applications.
A/B
DISABLE
75Ω CABLE
0.1F
0.1F
R
75Ω
T
IN_A
OUT_
R
T
75Ω CABLE
75Ω
R
T
Applications Information
75Ω
75Ω CABLE
IN_B
Video Line Driver
R
T
75Ω
The MAX4028/MAX4029 are well suited to drive coaxial
transmission lines when the cable is terminated at both
ends, as shown in Figure 3, where the fixed gain of +2V/V
CLAMP
compensates for the loss in the resistors, R .
T
MAX4028
MAX4029
R
KEYREF
Driving Capacitive Loads
A correctly terminated transmission line is purely
resistive and presents no capacitive load to the amplifier.
Reactive loads decrease phase margin and may produce
excessive ringing and oscillation.
Figure 3. Video Line Driver
Although the MAX4028/MAX4029 are optimized for AC
performance and are not designed to drive highly capaci-
tive loads, they are capable of driving up to 15pF without
oscillations. However, some peaking may occur in the fre-
quency domain (Figure 4). To drive larger capacitive loads
or to reduce ringing, add an isolation resistor between the
Another concern when driving capacitive loads is the
amplifier’s output impedance, which appears inductive
at high frequencies. This inductance forms an L-C
resonant circuit with the capacitive load, which causes
peaking in the frequency response and degrades the
amplifier’s phase margin.
Maxim Integrated
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MAX4028/MAX4029
Triple/Quad, 2:1 Video
Multiplexer-Amplifiers with Input Clamps
OPTIMAL ISOLATION RESISTANCE
SMALL-SIGNAL BANDWIDTH
vs. FREQUENCY
vs. CAPACITIVE LOAD
30
11
10
9
C
= 15pF
LOAD
25
20
15
10
5
C
= 10pF
LOAD
8
7
6
5
4
C
= 5pF
LOAD
3
2
0
1
0
50
100
C
150
(pF)
200
250
100k
1M
10M
FREQUENCY (Hz)
100M
1G
LOAD
Figure 4. Small-Signal Gain vs. Frequency with Capacitive
Load and No Isolation Resistor
Figure 6. Optimal Isolation Resistance vs. Capacitive Load
two layers: a signal and power layer on one side, and a
large, low-impedance ground plane on the other side.
The ground plane should be as free of voids as possible.
Whether or not a constant-impedance board is used, it is
best to observe the following guidelines when designing
the board:
A/B
DISABLE
75Ω CABLE
0.1F
IN_A
R
ISO
OUT_
R
T
75Ω
C
L
R
L
75Ω CABLE
0.1µF
1) Do not use wire-wrapped boards or breadboards.
IN_B
2) Do not use IC sockets; they increase parasitic capaci-
tance and inductance.
R
75Ω
T
CLAMP
3) Keep signal lines as short and straight as possible. Do
not make 90° turns; round all corners.
MAX4028
MAX4029
R
KEYREF
4) Observe high-frequency bypassing techniques to
maintain the amplifier’s accuracy and stability.
5) Use surface-mount components. They generally have
shorter bodies and lower parasitic reactance, yielding
better high-frequency performance than through-hole
components.
Figure 5. Using an Isolation Resistor (RISO) for a High-
Capacitive Load
amplifier’soutputandtheload(Figure5).ThevalueofR
ISO
depends on the circuit’s gain (+2V/V) and the capacitive
load (Figure 6). Also note that the isolation resistor forms a
divider that decreases the voltage delivered to the load.
The bypass capacitors should include a 0.1µF, ceramic
surface-mount capacitor between
V
and the
CC
ground plane, located as close to the package as
possible. Optionally, place a 10µF capacitor at the power
supply’s point-of-entry to the PCB to ensure the integrity of
incoming supplies. The power-supply traces should lead
Layout and Power-Supply Bypassing
The MAX4028/MAX4029 have high bandwidths and
consequently require careful board layout, including the
possible use of constant-impedance microstrip or stripline
techniques.
directly from the capacitor to the V
pin. To minimize
CC
parasitic inductance, keep PC traces short and use
surface-mount components.
To realize the full AC performance of these high-speed
amplifiers, pay careful attention to power-supply bypass-
ing and board layout. The PC board should have at least
If input termination resistors and output back-termination
resistors are used, they should be surface-mount types,
and should be placed as close as possible to the IC pins.
Maxim Integrated
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MAX4028/MAX4029
Triple/Quad, 2:1 Video
Multiplexer-Amplifiers with Input Clamps
Pin Configurations
TOP VIEW
IN4A
IN3A
1
2
3
4
5
6
7
8
9
20 CLAMP/KEY_4
19 DISABLE
18 OUT1
IN3A
1
2
3
4
5
6
7
8
16 DISABLE
IN2A
IN2A
IN1A
A/B
15 OUT1
IN1A
17 V
CC
14
V
CC
MAX4029
MAX4028
A/B
16 OUT2
13 OUT2
KEYREF
IN1B
15 CLAMP/KEY_2
KEYREF
IN1B
12 CLAMP/KEY_2
11 OUT3
14
OUT3
IN2B
13 GND
IN2B
10 GND
IN3B
12 CLAMP/KEY_3
11 OUT4
IN3B
9
CLAMP/KEY_3
IN4B 10
TSSOP/SO
TSSOP/SO
Chip Information
TRANSISTOR COUNT: 1032
PROCESS: Bipolar
Package Information
For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages. Note that a “+”,
“#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing
pertains to the package regardless of RoHS status.
PACKAGE TYPE
16 TSSOP
PACKAGE CODE
U16+1
OUTLINE NO.
21-0066
LAND PATTERN NO.
90-0117
16 Wide SO
20 TSSOP
W16+3
21-0042
90-0107
U20+2
21-0066
90-0116
20 Wide SO
W20+3
21-0042
90-0108
Maxim Integrated
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MAX4028/MAX4029
Triple/Quad, 2:1 Video
Multiplexer-Amplifiers with Input Clamps
Revision History
REVISION REVISION
PAGES
DESCRIPTION
CHANGED
NUMBER
DATE
0
3/04
Initial release
—
No /V OPNs; deleted “In Car Navigation/Entertainment” from Applications section
and automotive reference in General Description and Detailed Description sections;
updated Package Information and added Revision History table
1
4/15
1, 7, 12, 13
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses
are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits)
shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
©
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
2015 Maxim Integrated Products, Inc.
│ 12
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