MAX4028EUE-T [MAXIM]
Video Multiplexer, 3 Func, 1 Channel, BIPolar, PDSO16, 4.40 MM, MO-153, TSSOP-16;
| 型号： | MAX4028EUE-T |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Video Multiplexer, 3 Func, 1 Channel, BIPolar, PDSO16, 4.40 MM, MO-153, TSSOP-16 光电二极管 |
| 文件： | 总13页 (文件大小：311K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-3240; Rev 0; 3/04
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 sig-
nal, 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 selec-
table. Selectable clamp/key-clamp inputs and fixed-gain
video output buffers make the MAX4028/MAX4029 ideal
for video-source switching applications such as automo-
tive entertainment systems, video projectors, and dis-
plays/TVs. Both devices have 20ns channel switching
ꢀ 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
times and low 10mV
switching transients, making
P-P
them ideal for high-speed video switching applications
such as on-screen display (OSD) insertion.
Ordering Information
The MAX4028/MAX4029 have a -3dB large-signal (2V
)
P-P
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.
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
MAX4028EUE
MAX4028EWE
MAX4029EUP
MAX4029EWP
16 Wide SO
20 TSSOP
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.
20 Wide SO
Typical Operating Circuit
Applications
In-Car Navigation/Entertainment
A/B
+5V
Blade Servers
C
IN
0.1µF
V
CC
75Ω CABLE
Security Systems
IN1A
CLAMP
MAX4028
MAX4029
0.1µF
0.01µF
Video Projectors
75Ω
Displays and Digital Televisions
Broadcast and Graphics Video
Set-Top Boxes
75Ω CABLE
C
IN
0.1µF
75Ω
OUT1
75Ω CABLE
IN1B
CLAMP
1kΩ
75Ω
1kΩ
Notebook Computers
Video Crosspoint Switching
C
IN
0.1µF
75Ω CABLE
IN2A
CLAMP
75Ω
75Ω CABLE
75Ω
OUT2
C
IN
0.1µF
75Ω CABLE
Selector Guide
IN2B
CLAMP
1kΩ
75Ω
NO. OF 2:1
MUX-AMPS
PART
GAIN
1kΩ
DISABLE
KEYREF
MAX4028
MAX4029
3
4
2V/V
2V/V
R
KEYREF
6kΩ
KEY/CLAMP
CONTROL
CLAMP/KEY_2
Pin Configurations appear at end of data sheet.
________________________________________________________________ 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.
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 11ꢀW/°C above +70°C) ..........879ꢀW
20-Pin Wide SO (derate 10ꢀW/°C above +70°C) .......800ꢀW
Operating Teꢀperature Range ...........................-40°C to +85°C
Junction Teꢀperature......................................................+150°C
Storage Teꢀperature Range.............................-65°C to +150°C
Lead Teꢀperature (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 ................................................... 0.5ꢀA
+ 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 9.4ꢀW/°C above +70°C) .........755ꢀW
16-Pin Wide SO (derate 9.5ꢀW/°C above +70°C) ......762ꢀW
Note 1: Do not short V
to V
.
CC
OUT
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
MAX
CC
L
DISABLE
KEYREF
IN
A
MIN
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 Claꢀp Voltage
I
ꢀA
ꢀA
V
CC
MAX4029, R = ∞
55
L
MAX4028
MAX4029
15
V
= 0V
DISABLE
11
0.4
1.1
5
20
Claꢀp (Note 3)
0.32
0.48
V
CLAMP
Key claꢀp (Note 4)
Input Claꢀping Current
Claꢀp Voltage Matching
Claꢀp Voltage Drift
I
Input voltage = input claꢀp + 0.5V
Measured at output
18
µA
ꢀV
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
PSRR
4.5V < V
< 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
ꢀA
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
2
_______________________________________________________________________________________
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.
MAX
CC
L
DISABLE
KEYREF
IN
A
MIN
Typical values are at T = +25°C.)
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
210
130
MAX
UNITS
MHz
Sꢀall-Signal -3dB Bandwidth
Large-Signal -3dB Bandwidth
BW
BW
V
V
= 100ꢀV
SS
LS
OUT
OUT
P-P
P-P
= 2V
MHz
Sꢀall-Signal 0.1dB Gain Flatness
Bandwidth
BW
V
V
= 100ꢀV
P-P
30
30
MHz
MHz
0.1dBSS
OUT
OUT
Large-Signal 0.1dB Gain Flatness
Bandwidth
BW
= 2V
= 2V
0.1dBLS
SR
P-P
Slew Rate
V
V
300
20
V/µs
ns
OUT
OUT
P-P
Settling Tiꢀe to 0.1%
Power-Supply Rejection Ratio
Output Iꢀpedance
Differential Gain Error
Differential Phase Error
Group Delay
t
= 2V step
S
PSRR
f = 100kHz
55
dB
Z
f = 100kHz
0.7
0.2
0.4
1.0
70
Ω
O
DG
DP
5-step ꢀodulated staircase
5-step ꢀodulated 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
ISO
V
= 2V , f = 100kHz
108
dB
OUT_
P-P
Droop
D
Guaranteed by input claꢀp current
2
%
R
SWITCHING CHARACTERISTICS
Channel Switching Tiꢀe
Enable Tiꢀe
t
t
20
0.1
0.1
10
ns
µs
µs
SW
ON
Disable Tiꢀe
t
OFF
Switching Transient
ꢀV
P-P
Note 2: All devices are 100% production tested at T = +25°C. Specifications over teꢀperature are guaranteed by design.
A
Note 3: The claꢀp voltage at the input is V
(ꢀeasured at the output) divided by gain + V
.
BE
CLAMP
Note 4: The key-claꢀp voltage is above the sync-tip claꢀp voltage by approxiꢀately 0.7V, and is adjusted by varying R
Note 5: Measured at f = 100Hz at therꢀal equilibriuꢀ.
.
KEYREF
_______________________________________________________________________________________
3
Triple/Quad, 2:1 Video
Multiplexer-Amplifiers with Input Clamps
Typical Operating Characteristics
(V
noted.)
= +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
SMALL-SIGNAL BANDWIDTH
vs. FREQUENCY
SMALL-SIGNAL GAIN FLATNESS
vs. FREQUENCY
LARGE-SIGNAL BANDWIDTH
vs. FREQUENCY
8
7
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
P-P
V
= 2V
P-P
OUT
P-P
OUT
OUT
7
6
6
5
5
4
4
3
3
2
2
1
1
0
0
-1
-2
-1
-2
100k
1M
10M
100M
1G
1G
1G
100k
1M
10M
FREQUENCY (Hz)
100M
1G
100k
1M
10M
100M
1G
FREQUENCY (Hz)
FREQUENCY (Hz)
LARGE-SIGNAL GAIN FLATNESS
vs. FREQUENCY
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
DIFFERENTIAL GAIN AND PHASE
6.2
6.1
6.0
5.9
5.8
5.7
5.6
5.5
5.4
5.3
5.2
0
-10
-20
-30
-40
-50
-60
-70
0.3
0.2
0.1
V
= 2V
OUT
P-P
0
-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
100M
1k
10k
100k
1M
10M 100M 1G
FREQUENCY (Hz)
FREQUENCY (Hz)
ALL-HOSTILE CROSSTALK (A TO B ON ANY
CHANNEL) vs. FREQUENCY
OFF-ISOLATION
vs. FREQUENCY
ALL-HOSTILE CROSSTALK (CHANNEL TO
CHANNEL) vs. FREQUENCY
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
0
-20
0
-10
-20
-30
-40
-50
-60
-70
-80
-40
-60
-80
-100
-120
-140
100k
1M
10M
100M
1G
100k
1M
10M
100M
10k
100k
1M
10M
100M
1G
FREQUENCY (Hz)
FREQUENCY (Hz)
FREQUENCY (Hz)
4
_______________________________________________________________________________________
Triple/Quad, 2:1 Video
Multiplexer-Amplifiers with Input Clamps
Typical Operating Characteristics (continued)
(V
noted.)
= +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
OUTPUT IMPEDANCE
vs. FREQUENCY
INPUT-VOLTAGE NOISE DENSITY
vs. FREQUENCY
LARGE-SIGNAL TRANSIENT RESPONSE
MAX4028 toc12
100
1000
100
10
V
IN
1.6VDC
500mV/div
10
1
V
OUT
1V/div
0.1
1
10k
100k
1M
10M
100M
1G
1
10
100
1k
10k
100k
1M
10ns/div
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
5VDC
A/B
2.5V/div
V
A/B
2.5V/div
IN
1.6VDC
25mV/div
0VDC
V
SIGNAL 2
50mV/div
V
OUT
500mV/div
OUT
20mV/div
20ns/div
10ns/div
20ns/div
SMALL-SIGNAL BANDWIDTH
vs. FREQUENCY
OPTIMAL ISOLATION RESISTANCE
vs. CAPACITIVE LOAD
ENABLE RESPONSE TIME
(V
= 0.5V)
OUT
MAX4028 toc16
11
10
9
30
25
20
15
10
5
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
250mV/div
3
2
1
0
100k
1M
10M
FREQUENCY (Hz)
100M
1G
0
50
100
150
(pF)
200
250
50ns/div
C
LOAD
_______________________________________________________________________________________
5
Triple/Quad, 2:1 Video
Multiplexer-Amplifiers with Input Clamps
Typical Operating Characteristics (continued)
(V
noted.)
= +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
KEY-CLAMP REFERENCE VOLTAGE
CLAMP VOLTAGE
vs. TEMPERATURE
vs. R
KEYREF
1.8
0.43
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
1
3
5
7
9
11
13
-50
-25
0
25
50
75
100
R
(kΩ)
KEYREF
TEMPERATURE (°C)
Pin Description
PIN
NAME
FUNCTION
MAX4028
MAX4029
—
1
1
2
3
4
IN4A
IN3A
IN2A
IN1A
Aꢀplifier Input 4A
Aꢀplifier Input 3A
Aꢀplifier Input 2A
Aꢀplifier Input 1A
2
3
Channel-Select Input. Drive A/B high or leave floating to select channel A.
Drive A/B low to select channel B.
4
5
5
6
A/B
Key-Claꢀp Reference Output. Connect an external resistor froꢀ KEYREF to GND to
generate the key-claꢀp voltage.
KEYREF
6
7
7
8
IN1B
IN2B
IN3B
IN4B
OUT4
Aꢀplifier Input 1B
Aꢀplifier Input 2B
Aꢀplifier Input 3B
Aꢀplifier Input 4B
Aꢀplifier Output 4
8
9
—
—
10
11
Output 3 Claꢀp or Key-Claꢀp Input. Drive CLAMP/KEY_3 high to claꢀp OUT3.
Drive CLAMP/KEY_3 low to key claꢀp OUT3.
9
12
CLAMP/KEY_3
10
11
13
14
GND
Ground
OUT3
Aꢀplifier Output 3
Output 2 Claꢀp or Key-Claꢀp Input. Drive CLAMP/KEY_2 high to claꢀp OUT2.
Drive CLAMP/KEY_2 low to key claꢀp OUT2.
12
13
14
15
16
17
CLAMP/KEY_2
OUT2
Aꢀplifier Output 2
Power-Supply Voltage. Bypass V
close to the pin as possible.
to GND with 0.1µF and 0.01µF capacitors as
CC
V
CC
6
_______________________________________________________________________________________
Triple/Quad, 2:1 Video
Multiplexer-Amplifiers with Input Clamps
Pin Description (continued)
PIN
NAME
OUT1
FUNCTION
MAX4028
MAX4029
15
18
Aꢀplifier Output 1
Disable Input. Pull DISABLE high for norꢀal operation. Drive DISABLE low to disable
all outputs.
16
19
20
DISABLE
Output 4 Claꢀp or Key-Claꢀp Input. Drive CLAMP/KEY_4 high to claꢀp OUT4.
Drive CLAMP/KEY_4 low to key claꢀp OUT4.
—
CLAMP/KEY_4
Detailed Description
V
CC
The MAX4028/MAX4029 are 5V, triple/quad, 2:1 voltage-
feedback ꢀultiplexer-aꢀplifiers with input claꢀps and a
fixed gain of +2V/V (6dB). Channel 1 (IN1A and IN1B)
IN1A
IN1B
CLAMP
CLAMP
inputs are claꢀped to the video sync tip of the input
OUT1
IN1_ channel, while the reꢀaining inputs can be
1kΩ
claꢀped 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
claꢀp and is pin selectable. Selectable claꢀp/key-
claꢀp inputs and fixed-gain video output buffers ꢀake
the MAX4028/MAX4029 ideal for video-source switching
1kΩ
IN2A
IN2B
CLAMP/
KEY
CLAMP
applications such as autoꢀotive entertainꢀent systeꢀs,
OUT2
video projectors, and displays/TVs. Both devices have
1kΩ
20ns channel switching tiꢀes and low 10ꢀV
switch-
P-P
CLAMP/
KEY
CLAMP
ing transients, ꢀaking theꢀ ideal for both high-speed
video switching applications such as OSD insertion.
1kΩ
CLAMP/KEY_2
IN3A
The MAX4028/MAX4029 have a -3dB large-signal (2V
)
P-P
bandwidth of 130MHz, a -3dB sꢀall-signal bandwidth of
210MHz, and a 300V/µs slew rate. Low differential gain
and phase errors of 0.2% and 0.4°, respectively, ꢀake
these devices ideal for broadcast video applications.
CLAMP/
KEY
CLAMP
OUT3
IN3B
1kΩ
CLAMP/
KEY
CLAMP
Sync Tip and Key Clamps
The MAX4028/MAX4029 have AC-coupled inputs, with
either a sync tip or key claꢀp to provide bias for the
video signal. Channel 1 of the MAX4028/MAX4029
always has a sync tip claꢀp at the input, while the
reꢀaining channels are selectable as either sync tip or
key claꢀps to accoꢀꢀodate the various video wave-
forꢀs (see the Clamp/Key-Clamp Settings for Video
Formats section). The value of the sync-tip claꢀp voltage
is set internally for the lowest value, consistent with linear
operation, and cannot be adjusted. The key-claꢀp volt-
age is adjustable, to coꢀpensate for variations in the
voltage between coꢀponent video inputs such as Linear
1kΩ
CLAMP/KEY_3
A/B
IN4A
CLAMP/
KEY
CLAMP
OUT4
IN4B
1kΩ
CLAMP/
KEY
CLAMP
1kΩ
CLAMP/KEY_4
KEYREF
CLAMP
VOLTAGE
DISABLE
MAX4029
RGB, YPbPr, and Y-C, by varying R
claꢀp voltage can be coꢀputed froꢀ:
. The key-
KEYREF
V
= 0.40 + 2000/[(5000 x R
) /
KEYREF
GND
Key-Claꢀp
(5000 + R
)]
KEYREF
Figure 1. MAX4029 Functional Diagram
_______________________________________________________________________________________
7
Triple/Quad, 2:1 Video
Multiplexer-Amplifiers with Input Clamps
Therefore, a 6kΩ resistor will produce a 1.13V key-
tion to the capacitor, a low resistance (≤75Ω) is required
claꢀp voltage as shown in Figure 2. The claꢀp voltage
on the source side to return the capacitor to ground. The
claꢀps used here are active devices with the coupling
capacitor serving two functions; first, as a charge reser-
voir to ꢀaintain the claꢀp voltage, and second, as the
coꢀpensation capacitor for the claꢀp itself. If an input is
not used, it ꢀust be terꢀinated to avoid causing oscilla-
tions that could couple with another input.
(V
) is ꢀeasured at the output; the voltage at the
CLAMP
input is V
(sync tip or key claꢀp) divided by the
CLAMP
gain (+2V/V) + V
.
BE
In order for these claꢀps (sync tip or key) to work proper-
ly, the input ꢀust be coupled with a 0.1µF capacitor (typ)
with low leakage (<1µA to 2µA, ꢀax). Without proper cou-
pling, the claꢀp voltage will change during the horizontal
line tiꢀe causing the “black level” to vary, changing the
iꢀage brightness froꢀ left to right on the display. In addi-
In general, a sync-tip claꢀp is used for coꢀposite video
(Cvbs), gaꢀꢀa corrected priꢀaries (R’G’B’), and the
luꢀa signal (Y) in S-video. A key claꢀp is preferred for
coꢀponent color difference signals (Pb and Pr), linear
priꢀaries (RGB in PCs), and chroꢀa (C) in S-video. The
rule is to sync tip claꢀp a signal if sync is present and
key claꢀp all others. Several exaꢀples are given in the
Clamp/Key-Clamp Settings for Video Formats section.
KEY-CLAMP REFERENCE VOLTAGE
vs. R
KEYREF
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
Clamp/Key-Clamp Settings for Video Formats
Tables 1 and 2 provide the claꢀp settings on the
MAX4028/MAX4029 to interface with various video forꢀats.
Low-Power, High-Impedance Disable Mode
All parts feature a low-power, high-iꢀpedance disable
ꢀode that is activated by driving the DISABLE input
low. Placing the aꢀplifier in disable ꢀode reduces the
quiescent supply current and places the output iꢀped-
ance at 2kΩ typically. Multiple devices can be paral-
leled to construct larger switch ꢀatrices by connecting
the outputs of several devices together and disabling
all but one of the paralleled aꢀplifiers’ 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
Cvbs1
CLAMP/KEY
Claꢀp
INPUT
FORMAT
CLAMP/KEY
Claꢀp
1
2
3
1
2
3
Y
C
Cvbs2
Claꢀp
Key
Cvbs3
Claꢀp
Cvbs
Claꢀp
INPUT
FORMAT
CLAMP/KEY
Claꢀp
INPUT
FORMAT
CLAMP/KEY
Claꢀp
Key
1
2
3
G’
B’
R’
1
2
3
Y
Claꢀp
Pb
Pr
Claꢀp
Key
R, G, B have sync on all.
INPUT
FORMAT
CLAMP/KEY
Claꢀp
Key
1
2
3
Gs
B
R
Key
Gs, B, R have sync only on Green.
8
_______________________________________________________________________________________
Triple/Quad, 2:1 Video
Multiplexer-Amplifiers with Input Clamps
Table 2. MAX4029 Clamp Settings for Video Formats
INPUT
FORMAT
Cvbs1
Cvbs2
Cvbs3
Cvbs4
CLAMP/KEY
INPUT
FORMAT
CLAMP/KEY
Claꢀp
Key
1
2
3
4
Claꢀp
1
2
3
4
Gs
R
Claꢀp
Claꢀp
B
Key
Claꢀp
Cvbs
Claꢀp
Gs, B, R have sync only on Green.
INPUT
FORMAT
CLAMP/KEY
Claꢀp
Key
INPUT
FORMAT
CLAMP/KEY
Claꢀp
Key
1
2
3
4
Y
Pr
1
2
3
4
H-Sync
G
B
R
Pb
Key
Key
Cvbs
Claꢀp
Key
R, G, B have sync on none.
INPUT
FORMAT
CLAMP/KEY
Claꢀp
INPUT
FORMAT
CLAMP/KEY
Claꢀp
1
2
3
4
Y
1
2
3
4
Cvbs
G’
C
Key
Claꢀp
Cvbs
Cvbs
Claꢀp
B’
Claꢀp
Claꢀp
R’
Claꢀp
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-filꢀ resistors. The
iꢀpedance of the internal feedback resistors ꢀust be
taken into account when operating ꢀultiple MAX4028/
MAX4029s in large ꢀultiplexer applications.
A/B
DISABLE
75Ω CABLE
0.1µF
0.1µF
R
T
IN_A
75Ω
OUT_
R
T
75Ω CABLE
75Ω
R
T
Applications Information
75Ω
75Ω CABLE
IN_B
Video Line Driver
The MAX4028/MAX4029 are well suited to drive coaxial
transꢀission lines when the cable is terꢀinated at both
ends, as shown in Figure 3, where the fixed gain of
R
T
75Ω
CLAMP
+2V/V coꢀpensates for the loss in the resistors, R .
T
R
KEYREF
MAX4028
MAX4029
Driving Capacitive Loads
A correctly terꢀinated transꢀission line is purely resis-
tive and presents no capacitive load to the aꢀplifier.
Reactive loads decrease phase ꢀargin and ꢀay pro-
duce excessive ringing and oscillation.
Figure 3. Video Line Driver
nant circuit with the capacitive load, which causes
peaking in the frequency response and degrades the
aꢀplifier’s phase ꢀargin.
Another concern when driving capacitive loads is the
aꢀplifier’s output iꢀpedance, which appears inductive
at high frequencies. This inductance forꢀs an L-C reso-
_______________________________________________________________________________________
9
Triple/Quad, 2:1 Video
Multiplexer-Amplifiers with Input Clamps
SMALL-SIGNAL BANDWIDTH
vs. FREQUENCY
OPTIMAL ISOLATION RESISTANCE
vs. CAPACITIVE LOAD
11
10
9
30
25
20
15
10
5
C
LOAD
= 15pF
C
LOAD
= 10pF
8
7
6
5
4
C
LOAD
= 5pF
3
2
1
0
100k
1M
10M
FREQUENCY (Hz)
100M
1G
0
50
100
150
(pF)
200
250
C
LOAD
Figure 4. Small-Signal Gain vs. Frequency with Capacitive
Load and No Isolation Resistor
Figure 6. Optimal Isolation Resistance vs. Capacitive Load
gain (+2V/V) and the capacitive load (Figure 6). Also
note that the isolation resistor forꢀs a divider that
decreases the voltage delivered to the load.
A/B
DISABLE
75Ω CABLE
0.1µF
0.1µF
Layout and Power-Supply Bypassing
The MAX4028/MAX4029 have high bandwidths and
consequently require careful board layout, including
the possible use of constant-iꢀpedance ꢀicrostrip or
stripline techniques.
IN_A
R
ISO
OUT_
R
T
75Ω
C
R
L
L
75Ω CABLE
IN_B
To realize the full AC perforꢀance of these high-speed
aꢀplifiers, pay careful attention to power-supply
bypassing and board layout. The PC board should
have at least two layers: a signal and power layer on
one side, and a large, low-iꢀpedance ground plane on
the other side. The ground plane should be as free of
voids as possible. Whether or not a constant-iꢀped-
ance board is used, it is best to observe the following
guidelines when designing the board:
R
T
75Ω
CLAMP
R
KEYREF
MAX4028
MAX4029
1) Do not use wire-wrapped boards or breadboards.
Figure 5. Using an Isolation Resistor (R
Capacitive Load
) for a High-
ISO
2) Do not use IC sockets; they increase parasitic
capacitance and inductance.
3) Keep signal lines as short and straight as possible.
Although the MAX4028/MAX4029 are optiꢀized for AC
perforꢀance and are not designed to drive highly
capacitive loads, they are capable of driving up to
15pF without oscillations. However, soꢀe peaking ꢀay
occur in the frequency doꢀain (Figure 4). To drive larg-
er capacitive loads or to reduce ringing, add an isola-
tion resistor between the aꢀplifier’s output and the load
Do not ꢀake 90° turns; round all corners.
4) Observe high-frequency bypassing techniques to
ꢀaintain the aꢀplifier’s accuracy and stability.
5) Use surface-ꢀount coꢀponents. They generally
have shorter bodies and lower parasitic reactance,
yielding better high-frequency perforꢀance than
through-hole coꢀponents.
(Figure 5). The value of R
depends on the circuit’s
ISO
10 ______________________________________________________________________________________
Triple/Quad, 2:1 Video
Multiplexer-Amplifiers with Input Clamps
The bypass capacitors should include a 0.1µF, ceraꢀic
surface-ꢀount capacitor between V and the 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 PC board to ensure the integrity of
incoꢀing supplies. The power-supply traces should lead
directly froꢀ the capacitor to the V
parasitic inductance, keep PC traces short and use sur-
face-ꢀount coꢀponents.
pin. To ꢀiniꢀize
CC
CC
If input terꢀination resistors and output back-terꢀination
resistors are used, they should be surface-ꢀount types,
and should be placed as close to the IC pins as possible.
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
15 OUT1
IN2A
IN2A
IN1A
IN1A
17 V
CC
14
V
CC
MAX4029
MAX4028
A/B
16 OUT2
A/B
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
______________________________________________________________________________________ 11
Triple/Quad, 2:1 Video
Multiplexer-Amplifiers with Input Clamps
Package Information
(The package drawing(s) in this data sheet ꢀay not reflect the ꢀost current specifications. For the latest package outline inforꢀation,
go to www.maxim-ic.com/packages.)
12 ______________________________________________________________________________________
Triple/Quad, 2:1 Video
Multiplexer-Amplifiers with Input Clamps
Package Information (continued)
(The package drawing(s) in this data sheet ꢀay not reflect the ꢀost current specifications. For the latest package outline inforꢀation,
go to www.maxim-ic.com/packages.)
INCHES
MILLIMETERS
N
MAX
MAX
2.65
0.30
0.49
0.32
DIM
A
MIN
MIN
2.35
0.10
0.35
0.23
0.093
0.004
0.014
0.009
0.104
0.012
0.019
0.013
A1
B
C
e
0.050
1.27
H
E
E
0.291
0.394
0.016
0.299
0.419
0.050
7.40
10.00
0.40
7.60
10.65
1.27
H
L
VARIATIONS:
INCHES
1
MILLIMETERS
TOP VIEW
MAX
0.413
0.463
0.512
0.614
0.713
MAX
DIM
D
MIN
MIN
10.10
11.35
12.60
15.20
17.70
N MS013
0.398
0.447
0.496
0.598
0.697
10.50 16 AA
11.75 18 AB
13.00 20 AC
15.60 24 AD
18.10 28 AE
D
D
D
D
D
C
A
B
e
0 -8
A1
L
FRONT VIEW
SIDE VIEW
PROPRIETARY INFORMATION
TITLE:
PACKAGE OUTLINE, .300" SOIC
APPROVAL
DOCUMENT CONTROL NO.
REV.
1
21-0042
B
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 13
© 2004 Maxiꢀ Integrated Products
Printed USA
is a registered tradeꢀark of Maxiꢀ Integrated Products.
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