MAX442ESA [MAXIM]
140MHz, 2-Channel Video Multiplexer/Amplifier; 140MHz的， 2路视频多路复用器/放大器
| 型号： | MAX442ESA |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | 140MHz, 2-Channel Video Multiplexer/Amplifier |
| 文件： | 总8页 (文件大小：95K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-0016; Rev 1; 1/95
1 4 0 MHz, 2 -Ch a n n e l
Vid e o Mu lt ip le x e r/Am p lifie r
MAX42
_______________Ge n e ra l De s c rip t io n
____________________________Fe a t u re s
♦ 140MHz Unity-Gain Bandwidth
♦ 250V/µs Slew Rate
The MAX442 combines a 140MHz video amplifier with a
high-speed, 2-channel multiplexer in an 8-pin package.
With its 36ns switching time and low differential gain
(0.07%) and phase (0.09°) errors, it is ideal for broad-
cast-quality video applications. The device is designed
to drive both 50Ω and 75Ω cables, and can directly
drive a 75Ω load to ±3V.
♦ 0.07%/0.09° Differential Gain/Phase Error
♦ 36ns Channel Switch Time
♦ No External Compensation Components
♦ 8-Pin DIP and SO Packages
The MAX442 video amplifier is compensated for unity-
gain stability, and features a 140MHz bandwidth and a
250V/µs slew rate. The multiplexer’s low input capaci-
tance (4pF with the channel on or off) maximizes high-
speed performance, and a ground pin separating the
two input channels minimizes crosstalk and simplifies
board layout.
♦ Directly Drives 50Ω and 75Ω Cables
______________Ord e rin g In fo rm a t io n
The MAX442 operates from ±5V supplies and typically
consumes 300mW. For applications that require more
input channels, see the data sheets for the MAX440 8-
channel mux/amp and the MAX441 4-channel mux/amp.
PART
TEMP. RANGE
0°C to +70°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
8 Plastic DIP
8 SO
MAX442CPA
MAX442CSA
MAX442C/D
MAX442EPA
MAX442ESA
Dice*
8 Plastic DIP
8 SO
________________________Ap p lic a t io n s
Broadcast-Quality Video-Signal Multiplexing
Coaxial-Cable Drivers
*Dice are specified at T = +25°C, DC parameters only.
A
Video Editing
Video Security Systems
Medical Imaging
__________Typ ic a l Op e ra t in g Circ u it
High-Speed Signal Processing
+5V
0.1µF
__________________P in Co n fig u ra t io n
V+
TOP VIEW
MAX442
75Ω
CABLE
VIDEO
OUTPUT
75Ω
V
OUT
IN0
IN1
VIDEO
SIGNALS
IN
270Ω
75Ω
1
2
3
4
8
7
6
5
IN0
GND
IN1
A0
V+
V
IN-
MAX442
A0
OUT
270Ω
GND V-
IN-
V-
0.1µF
DIP/SO
CHANNEL
SELECT
-5V
________________________________________________________________ Maxim Integrated Products
1
Ca ll t o ll fre e 1 -8 0 0 -9 9 8 -8 8 0 0 fo r fre e s a m p le s o r lit e ra t u re .
1 4 0 MHz, 2 -Ch a n n e l
Vid e o Mu lt ip le x e r/Am p lifie r
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (V+ to V-).......................................................12V
Analog Input Voltage ............................(V+ + 0.3V) to (V- - 0.3V)
Digital Input Voltage .....................................-0.3V to (V+ + 0.3V)
Short-Circuit Current Duration ........................................1 minute
Input Current to Any Pin, Power On or Off........................±50mA
Operating Temperature Ranges
MAX442C_A........................................................0°C to +70°C
MAX442E_A.....................................................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10sec) .............................+300°C
Continuous Power Dissipation (T = +70°C)
A
Plastic DIP (derate 9.09mW/°C above +70°C) ............727mW
SO (derate 5.88mW/°C above +70°C).........................471mW
MAX42
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, V- = -5V, R = 150Ω, T = T
to T , unless otherwise noted.)
MAX
L
A
MIN
PARAMETER
DC PERFORMANCE
Input Voltage Range
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
V
V
IN
-2
2
T
= +25°C
±1.5
±7.0
±10
±12
±2.5
±5.0
±2
A
Input Offset Voltage
(All Channels)
V
MAX442C
MAX442E
mV
OS
T
A
= +25°C
±1
±0.6
±0.5
2.0
Offset Matching
mV
µA
(V
–V
)
OS0 OS1
T
A
= T to T
MIN MAX
T
= +25°C
A
Input Bias Current
(Channel On)
I
V
= 0V
= 0V
B
IN
T
A
= T
to T
±5
MIN
MAX
MAX
MAX
T
A
= +25°C
±50
±1
nA
µA
Input Leakage Current
(Channel Off)
I
V
IN
LKG
T
A
= T
to T
MIN
T
A
= +25°C
0.5
0.2
Input Resistance
(Channel On) (Note 1)
R
C
-2V ≤ V ≤ 2V
MΩ
pF
IN
CM
T
A
= T
to T
MIN
Input Capacitance
Channel on or off
4
IN
A
= 0dB
= 6dB
25
50
60
V
DC Output Resistance
R
mΩ
OUT
A
V
T
= +25°C
50
46
A
R
= 75Ω,
L
Open-Loop Voltage Gain
Common-Mode Rejection Ratio
Power-Supply Rejection Ratio
Output Voltage Swing
A
dB
dB
dB
V
VOL
-2V ≤ V
≤ +2V
OUT
T
A
= T
to T
MIN
MAX
MAX
MAX
MAX
T
A
= +25°C
46
50
80
CMRR
PSRR
-2V ≤ V ≤ +2V
IN
T
A
= T
to T
46
MIN
T
A
= +25°C
54
±4.75V to ±5.25V
T
A
= T
to T
54
MIN
T
A
= +25°C
±2.5
±2.0
±3.0
V
OUT
R = 75Ω
L
T
A
= T
to T
MIN
2
_______________________________________________________________________________________
1 4 0 MHz, 2 -Ch a n n e l
Vid e o Mu lt ip le x e r/Am p lifie r
MAX42
ELECTRICAL CHARACTERISTICS (continued)
(V+ = 5V, V- = -5V, R = 150Ω, T = T
to T , unless otherwise noted.)
MAX
L
A
MIN
PARAMETER
DYNAMIC PERFORMANCE
-3dB Bandwidth
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
BW
SR1
DP
A
= 0dB, R = 100Ω
140
250
MHz
V/µs
V
L
Slew Rate
Differential Phase Error
Differential Gain Error
Figure 1
0.09
0.07
degrees
%
DG
Figure 1
To 0.1% of final value,
Settling Time
t
s
50
ns
A
= 0dB, R = 150Ω, 2V step input
L
V
Crosstalk
X
f = 10MHz, R = 75Ω, A = 0dB, Figure 6
76
12
dB
TALK
S
V
nV/ Hz
Input Noise-Voltage Density
POWER REQUIREMENTS
e
f = 10kHz
√
n
Operating Supply-Voltage Range
V
±4.75
25
±5.25
35
V
S
T
= +25°C
30
28
A
Positive Supply Current
I
CC
V
= 0V
= 0V
MAX442C
MAX442E
22
38
mA
IN
19
41
T
A
= +25°C
23
35
Negative Supply Current
I
EE
V
IN
MAX442C
MAX442E
20
38
mA
17
41
SWITCHING CHARACTERISTICS
Logic Low Voltage
V
0.8
V
V
IL
Logic High Voltage
V
IH
2.4
Address Propagation Delay
Channel Switching Time
t
Figure 7
Figure 7 (Note 2)
24
36
ns
ns
APD
t
SW
Note 1: Incremental resistance for a common-mode voltage between ±2V.
Note 2: Channel Switching Time specified between two grounded input channels; does not include signal rise/fall times for switch-
ing between channels with different input voltages.
__________________________________________Typ ic a l Op e ra t in g Ch a ra c t e ris t ic s
(T = +25°C, unless otherwise noted.)
A
UNITY-GAIN OUTPUT IMPEDANCE
vs. FREQUENCY
CLOSED-LOOP GAIN
vs. FREQUENCY
OPEN-LOOP GAIN AND PHASE
vs. FREQUENCY
100
10
30
25
80
70
135
90
A
= 20dB
= 6dB
= 0dB
VCL
20
15
10
5
60
50
45
A
VCL
GAIN
A
VCL
0
40
30
20
10
0
-45
PHASE
-90
1
0
-135
-180
-225
-270
-315
-5
0.1
0.01
-10
-15
-20
-10
-20
10k
100k
1M
10M
100M
0.1
1
10
100
1000
0.001
0.1
10
1000
FREQUENCY (Hz)
FREQUENCY (MHz)
FREQUENCY (MHz)
_______________________________________________________________________________________
3
1 4 0 MHz, 2 -Ch a n n e l
Vid e o Mu lt ip le x e r/Am p lifie r
____________________________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 )
(T = +25°C, unless otherwise noted.)
A
VOLTAGE-NOISE DENSITY
OUTPUT VOLTAGE SWING
vs. LOAD RESISTANCE
CROSSTALK
vs. FREQUENCY
vs. FREQUENCY
5
4
3
2
1
0
-20
1000
MAX42
100
10
1
-40
-60
0
-1
-2
-80
-3
-4
-5
-100
-120
1
10
100
1k
10k
100k
10
100
1k
10k
1
10
100
1000
FREQUENCY (Hz)
LOAD RESISTANCE (Ω)
FREQUENCY (MHz)
INPUT OFFSET VOLTAGE
vs. TEMPERATURE
INPUT BIAS CURRENT
vs. TEMPERATURE
SUPPLY CURRENT
vs. TEMPERATURE
5
1.0
40
30
V
CM
= 0V
I
CC
4
3
0.9
0.8
0.7
0.6
0.5
0.4
0.3
20
10
0
2
1
0
-1
-2
-10
-20
-30
-40
I
EE
-3
-4
-5
0.2
0.1
0
-40 -20
0
20
40 60
80 100
-40 -20
0
20
40 60
80 100
-40 -20
0
20
40 60
80 100
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
OPEN-LOOP VOLTAGE GAIN
vs. TEMPERATURE
COMMON-MODE REJECTION RATIO
vs. TEMPERATURE
DIFFERENTIAL INPUT OFFSET VOLTAGE
vs. TEMPERATURE
80
80
3
70
60
50
40
30
70
60
50
40
30
2
1
0
-1
-2
-3
20
10
0
20
10
0
-40 -20
0
20
40 60
80 100
-40 -20
0
20
40 60
80 100
-40 -20
0
20
40 60
80 100
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
4
_______________________________________________________________________________________
1 4 0 MHz, 2 -Ch a n n e l
Vid e o Mu lt ip le x e r/Am p lifie r
MAX42
To prevent oscillation and unwanted signal coupling,
_____________________P in De s c rip t io n
minimize trace area at the circuit’s critical high-imped-
ance nodes, especially the amplifier summing junction
(the amplifier’s inverting input). Surround these critical
nodes with a ground trace, and include ground traces
between all signal traces to minimize parasitic coupling
that can degrade crosstalk and/or amplifier stability.
Keep signal paths as short as possible to minimize
inductance, and keep all input channel traces at equal
lengths to maintain the phase relationship between the
input channels.
PIN
1
NAME
IN0
FUNCTION
Analog Input, channel 0
Ground
2
GND
IN1
3
Analog Input, channel 1
Negative Power Supply, -5V
Amplifier Inverting Input
Amplifier Output
4
V-
5
IN-
Bypass all power-supply pins directly to the ground
plane with 0.1µF ceramic capacitors, placed as close
to the supply pins as possible. For high-current loads,
it may be necessary to include 1µF tantalum or alu-
minum-electrolytic capacitors in parallel with the 0.1µF
c e ra mic b yp a s s c a p a c itors . Ke e p c a p a c itor le a d
lengths as short as possible to minimize series induc-
tance; surface-mount (chip) capacitors are ideal for this
application.
6
V
OUT
7
V+
A0
Positive Power Supply, +5V
Channel Address Input:
A0 = logic 0 selects channel 0,
A0 = logic 1 selects channel 1
8
__________Ap p lic a t io n s In fo rm a t io n
Diffe re n t ia l Ga in a n d P h a s e Erro rs
In color video applications, lowest differential gain and
phase errors are critical for an IC, because they cause
changes in contrast and color of the displayed picture.
Typically, the MAX442’s multiplexer/amplifier combina-
tion has a differential gain and phase error of only
0.07% and 0.09°, respectively. This low differential
gain and phase error makes the MAX442 ideal for use
in broadcast-quality color video systems.
The MAX442’s bipolar construction results in a typical
channel input capacitance of only 4pF, whether the
channel is on or off. As with all ICs, the mux’s input
capacitance forms a single-pole RC lowpass filter with
the signal source’s output impedance. This filter can
limit the system’s signal bandwidth if the RC product
becomes too large. However, the MAX442’s low chan-
nel input capacitance allows full AC performance of the
amplifier, even with source impedances as great as
250Ω—a significant improvement over common mux or
switch alternatives.
Co a x ia l-Ca b le Drive rs
High-speed performance and excellent output current
capability make the MAX442 ideal for driving 50Ω or
75Ω coaxial cables. The MAX442 will drive 50Ω and
75Ω coaxial cables to ±3V.
Feedback resistors should be limited to no more than
500Ω to ensure that the RC time constant formed by the
re s is tors , the c irc uit b oa rd ’s c a p a c ita nc e , a nd the
capacitance of the amplifier input pins does not limit
the system’s high-speed performance.
75Ω
CABLE
P o w e r-S u p p ly Byp a s s in g
a n d Bo a rd La yo u t
75Ω
Realizing the full AC performance of high-speed ampli-
fiers requires careful attention to power-supply bypass-
ing and board layout. Use a low-impedance ground
plane with the MAX442. With multilayer boards, the
ground plane should be located on the PC board’s
component side to minimize impedance between the
components and the ground plane. For single-layer
boards, components should be mounted on the board’s
copper side and the ground plane should include the
entire portion of the board that is not dedicated to a
specific signal trace.
75Ω
CABLE
MAX442
75Ω
75Ω
CABLE
75Ω
75Ω
470Ω
SOURCE:
TEKTRONIX
1910 DIGITAL GENERATOR
470Ω
MEASUREMENT:
TEKTRONIX
VM700 VIDEO
MEASUREMENT SET
Figure 1. Differential Gain and Phase Error Test Circuit
_______________________________________________________________________________________
5
1 4 0 MHz, 2 -Ch a n n e l
Vid e o Mu lt ip le x e r/Am p lifie r
The Typical Operating Circuit shows the MAX442 dri-
ving a back-terminated 75Ω video cable. The back-ter-
mination resistor (at the MAX442 output) is included to
match the impedance of the cable’s driven end to the
characteristic impedance of the cable itself. This, plus
the load-termination resistor, eliminates signal reflec -
tions from the cable’s ends. The back-termination resis-
tor forms a voltage divider with the load impedance,
which attenuates the signal at the cable output by one-
half. The amplifier is operated with a 2V/V closed-loop
gain to provide unity gain at the cable’s video output.
lowe rs . The a mp lifie r’s outp ut imp e d a nc e a nd the
capacitive load form an RC filter that adds a pole to the
loop response. If the pole frequency is low enough, as
when driving a large capacitive load, the circuit phase
margin is degraded and oscillation may occur.
With capacitive loads greater than approximately 50pF
and the MAX442 configured as a unity-gain buffer, use
an isolation resistor in series with the load, as shown in
Figure 2. The resistor removes the pole from the loop
response caused by the load capacitance.
MAX42
Ch a n n e l S w it c h in g Tim e /Tra n s ie n t
When the MAX442 multiplexer is switched from one
channel to another, a small glitch will appear at the out-
put. Figure 3 shows the results of putting a 0V to 5V
pulse 100ns wide into A0.
Ca p a c it ive -Lo a d Drivin g
Driving large capacitive loads increases the likelihood
of oscillation in most amplifier circuits. This is especial-
ly true for circuits with high loop gains, like voltage fol-
MAX442
INPUT
GND
1V/div
IN
22Ω
OUT
C
LOAD
> 50pF
CABLE
OUTPUT
GND
500mV/div
Figure 2. Capacitive-Load-Driving Circuit
Figure 4. Pulse Response with R = 100Ω (50Ω back-terminated
L
cable), A
= +1V/V
VCL
A0 INPUT
5V/div
GND
GND
INPUT
1V/V
GND
GND
AMP
OUTPUT
200mV/div
CABLE
OUTPUT
1V/V
Figure 3. Output Switching Transient when Switching Between
Two Grounded Inputs with R = 100Ω
Figure 5. Pulse Response with R = 100Ω (50Ω back-terminated
L
cable), A
= +2V/V
L
VCL
6
_______________________________________________________________________________________
1 4 0 MHz, 2 -Ch a n n e l
Vid e o Mu lt ip le x e r/Am p lifie r
MAX42
___________________Ch ip To p o g ra p h y
A0
MAX442
(MEASURED WITH
CHANNEL 0
SELECTED)
IN0
IN0
IN1
V+
V
OUT
75Ω
0. 066"
150Ω
(1. 676mm)
A0
GND
IN1
OUT
IN-
V
= 1V at 10MHz,
p-p
IN
V-
R = 75Ω
S
0. 066"
(1. 676mm)
V
TRANSISTOR COUNT: 137
SUBSTRATE CONNECTED TO V-
OUT
CROSSTALK = 20log
10
V
IN
Figure 6. Crosstalk Test Circuit
t
APD
A0
V
OUT
t
SW
Figure 7. Switch Timing
_______________________________________________________________________________________
7
1 4 0 MHz, 2 -Ch a n n e l
Vid e o Mu lt ip le x e r/Am p lifie r
________________________________________________________P a c k a g e In fo rm a t io n
INCHES
MILLIMETERS
DIM
E
MIN
MAX
0.200
–
MIN
–
MAX
5.08
–
A
–
E1
D
A1 0.015
A2 0.125
A3 0.055
0.38
3.18
1.40
0.41
1.14
0.20
0.13
7.62
6.10
2.54
7.62
–
0.175
0.080
0.022
0.065
0.012
0.080
0.325
0.310
–
4.45
2.03
0.56
1.65
0.30
2.03
8.26
7.87
–
A3
A2
A1
MAX42
A
L
B
0.016
B1 0.045
0.008
D1 0.005
0.300
E1 0.240
0.100
eA 0.300
C
0° - 15°
E
C
e
e
B1
eA
eB
–
–
B
eB
L
–
0.400
0.150
10.16
3.81
0.115
2.92
D1
INCHES
MILLIMETERS
PKG. DIM
PINS
Plastic DIP
PLASTIC
DUAL-IN-LINE
PACKAGE
(0.300 in.)
MIN
MAX MIN
MAX
8
P
P
P
P
P
N
D
D
D
D
D
D
0.348 0.390 8.84
9.91
14
16
18
20
24
0.735 0.765 18.67 19.43
0.745 0.765 18.92 19.43
0.885 0.915 22.48 23.24
1.015 1.045 25.78 26.54
1.14 1.265 28.96 32.13
21-0043A
INCHES
MILLIMETERS
DIM
MIN
0.053
MAX
0.069
0.010
0.019
0.010
0.157
MIN
1.35
0.10
0.35
0.19
3.80
MAX
1.75
0.25
0.49
0.25
4.00
A
D
A1 0.004
B
C
E
e
0.014
0.007
0.150
0°-8°
A
0.101mm
0.004in.
0.050
1.27
e
H
L
0.228
0.016
0.244
0.050
5.80
0.40
6.20
1.27
A1
C
B
L
INCHES
MILLIMETERS
DIM PINS
Narrow SO
SMALL-OUTLINE
PACKAGE
MIN MAX
MIN
MAX
5.00
8.75
8
0.189 0.197 4.80
D
D
D
E
H
14 0.337 0.344 8.55
16 0.386 0.394 9.80 10.00
21-0041A
(0.150 in.)
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
© 1995 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
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