MAX468CPE [MAXIM]
Two-Channel, Triple/Quad RGB Video Switches and Buffers; 双通道，三/四路RGB视频开关及缓冲器
| 型号： | MAX468CPE |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Two-Channel, Triple/Quad RGB Video Switches and Buffers |
| 文件： | 总16页 (文件大小：164K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-0219; Rev 2; 6/94
Tw o -Ch a n n e l, Trip le /Qu a d
RGB Vid e o S w it c h e s a n d Bu ffe rs
63–MAX470
_______________Ge n e ra l De s c rip t io n
____________________________Fe a t u re s
♦ 100MHz Unity-Gain Bandwidth
The MAX463–MAX470 s e rie s of two-c ha nne l,
triple/quad buffered video switches and video buffers
combines high-accuracy, unity-gain-stable amplifiers
with high-performance video switches. Fast switching
time and low differential gain and phase error make this
series of switches and buffers ideal for all video appli-
cations. The devices are all specified for ±5V supply
operation with inputs and outputs as high as ±2.5V
when driving 150Ω loads (75Ω back-terminated cable).
♦ 90MHz Bandwidth with 2V/V Gain
♦ 0.01%/0.03° Differential Gain/Phase Error
♦ Drives 50Ω and 75Ω Back-Terminated Cable Directly
♦ Wide Output Swing:
±2V into 75Ω
±2.5V into 150Ω
♦ 300V/µs Slew Rate (2V/V gain)
♦ 20ns Channel Switching Time
Input capacitance is typically only 5pF, and channel-to-
channel crosstalk is better than 60dB, accomplished by
surrounding all inputs with AC ground pins. The on-
board amplifiers feature a 200V/µs slew rate (300V/µs
♦ Logic Disable Mode:
High-Z Outputs
Reduced Power Consumption
for A = 2V/V amplifiers), and a bandwidth of 100MHz
V
♦ Outputs May Be Paralleled for Larger Networks
♦ 5pF Input Capacitance (channel on or off)
(90MHz for A = 2V/V buffers). Channel selection is
V
controlled by a single TTL-compatible input pin or by a
microprocessor interface, and channel switch time is
only 20ns.
______________Ord e rin g In fo rm a t io n
For design flexibility, devices are offered with buffer-
amplifier gains of 1V/V or 2V/V for 75Ω back-terminated
applications. Output amplifiers have a guaranteed out-
put swing of ±2V into 75Ω.
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
24 Narrow Plastic DIP
24 Wide SO
MAX463CNG
MAX463CWG
MAX463C/D
MAX463ENG
MAX463EWG
Dice*
Devices offered in this series are as follows:
24 Narrow Plastic DIP
24 Wide SO
VOLTAGE GAIN
PART
DESCRIPTION
(V/V)
Ordering Information continued on last page.
MAX463
MAX464
MAX465
MAX466
MAX467
MAX468
MAX469
MAX470
Triple RGB Switch & Buffer
Quad RGB Switch & Buffer
Triple RGB Switch & Buffer
Quad RGB Switch & Buffer
Triple Video Buffer
1
1
2
2
1
1
2
2
* Dice are specified at T = +25°C, DC parameters only.
A
_________________P in Co n fig u ra t io n s
TOP VIEW
IN0A
GND
IN1A
GND
IN2A
V-
1
2
3
4
5
6
7
8
9
24 GND
23 LE
Quad Video Buffer
Triple Video Buffer
MAX463
MAX465
22 EN
Quad Video Buffer
21 A0
20 CS
________________________Ap p lic a t io n s
19 V-
Broadcast-Quality Color-Signal Multiplexing
RGB Multiplexing
V-
18 OUT0
17 V+
IN0B
GND
RGB Color Video Overlay Editors
RGB Color Video Security Systems
RGB Medical Imaging
16 OUT1
15 GND
14 V+
IN1B 10
GND 11
IN2B 12
Coaxial-Cable Line Drivers
13 OUT2
DIP/SO
Typical Operating Circuit appears at end of data sheet.
Pin Configurations continued at end of data sheet.
________________________________________________________________ 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 .
Tw o -Ch a n n e l, Trip le /Qu a d
RGB Vid e o S w it c h e s a n d Bu ffe rs
ABSOLUTE MAXIMUM RATINGS
Power-Supply Ranges
24-Pin Narrow Plastic DIP
V+ to V- ................................................................................12V
Analog Input Voltage ..........................(V- - 0.3V) to (V+ + 0.3V)
Digital Input Voltage ...................................-0.3V to (V+ + 0.3V)
Output Short-Circuit Duration (to GND)........................1 Minute
Input Current into Any Pin, Power On or Off...................±50mA
(derate 20.2mW/°C above +70°C)..................................1620mW
24-Pin Wide SO (derate 19.3mW/°C above +70°C) .........1590mW
28-Pin Narrow Plastic DIP
(derate 20.2mW/°C above +70°C)..................................1620mW
28-Pin Wide SO (derate 18.1mW/°C above +70°C) .........1440mW
Operating Temperature Ranges
Continuous Power Dissipation (T = +70°C)
A
16-Pin Plastic DIP (derate 22.22mW/°C above +70°C) ....1778mW
16-Pin Wide SO (derate 20.00mW/°C above +70°C) .......1600mW
MAX4_ _C_ _.........................................................0°C to +70°C
MAX4_ _E_ _......................................................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10sec) .............................+300°C
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, -2V ≤ V ≤ +2V, R
= 75Ω, unless otherwise noted.)
IN
LOAD
63–MAX470
T
= +25°C
T
A
= T
MIN
to T
A
MIN MAX
PARAMETER
SYMBOL
CONDITIONS
UNITS
MIN TYP MAX
MAX
±5.25
2
Operating Supply Voltage
Input Voltage Range
Offset Voltage
V
S
±4.75 ±5 ±5.25
±4.75
-2
V
V
V
IN
-2
2
V
OS
±3
60
±1
±10
±15
mV
dB
µA
kΩ
pF
Power-Supply Rejection Ratio
On Input Bias Current
On Input Resistance
Input Capacitance
PSRR
50
50
I
±3
±5
BIAS
R
C
300 700
5
150
IN
IN
Channel off or on
MAX463/MAX464, MAX467/MAX468
(Note 1)
0.2
0.3
0.5
1.0
1.0
2.0
Voltage-Gain Accuracy
Output Voltage Swing
%
V
MAX465/MAX466, MAX469/MAX470,
R
R
R
= 150Ω, (Note 2)
LOAD
LOAD
LOAD
= 150Ω
±2.5 ±2.8
±2.0 ±2.4
5
±2.5
V
OUT
= 75Ω
-1.5/+2
f
IN
= 10MHz
MAX463/MAX464,
MAX467/MAX468
0.05
0.1
Output Impedance
R
OUT
Ω
f
IN
= DC
MAX465/MAX466,
MAX469/MAX470
MAX463/MAX464
MAX465/MAX466
150
0.7
250
1
100
0.7
kΩ
kΩ
Output Resistance,
Disabled Mode
R
C
OUTD
OUTD
Output Capacitance,
Disabled Mode
MAX463–MAX466
10
65
85
pF
MAX463/MAX465/MAX467/MAX469,
= 0V
80
100
120
V
IN
MAX464/MAX466/MAX468/MAX470,
= 0V
100
Positive Supply Current
I+
mA
V
IN
MAX463/MAX465, disabled mode
MAX464/MAX466, disabled mode
35
40
45
50
50
55
2
_______________________________________________________________________________________
Tw o -Ch a n n e l, Trip le /Qu a d
RGB Vid e o S w it c h e s a n d Bu ffe rs
63–MAX470
ELECTRICAL CHARACTERISTICS (continued)
(V+ = 5V, V- = -5V, -2V ≤ V ≤ +2V, R
= 75Ω, unless otherwise noted.)
IN
LOAD
T
= +25°C
T
= T
MIN
to T
MAX
A
A
MIN MAX
PARAMETER
SYMBOL
CONDITIONS
UNITS
MIN TYP MAX
MAX463/MAX465/MAX467/MAX469,
50
65
65
80
75
V
IN
= 0V
MAX464/MAX466/MAX468/MAX470,
= 0V
95
Negative Supply Current
I-
mA
V
IN
MAX463/MAX465, disabled mode
MAX464/MAX466, disabled mode
20
25
30
35
35
40
–—
Input Noise Density
Slew Rate
en
f
= 10kHz
20
nV/√Hz
IN
MAX463/MAX464, MAX467/MAX468
MAX465/MAX466, MAX469/MAX470
MAX463/MAX464, MAX467/MAX468
MAX465/MAX466, MAX469/MAX470
MAX463/MAX464, MAX467/MAX468
MAX465/MAX466, MAX469/MAX470
MAX463/MAX464, MAX467/MAX468
MAX465/MAX466, MAX469/MAX470
200
300
100
90
SR
BW
DG
DP
V/µs
MHz
%
-3dB Bandwidth
0.01
0.12
0.03
0.14
50
Differential Gain Error
(Note 3)
Differential Phase Error
(Note 3)
deg.
ns
Settling Time to 0.1%
t
V
= 2V-to-0V step
S
IN
Adjacent Channel Crosstalk
(Note 4)
XTALK
f
IN
= 10MHz
60
dB
All-Hostile Crosstalk (Note 5) XTALK
f
= 10MHz
50
70
dB
dB
IN
All-Hostile Off Isolation (Note 6)
ISO
f
IN
= 10MHz, MAX463–MAX466
Channel Switching
Propagation Delay (Note 7)
t
MAX463–MAX466
MAX463–MAX466
15
ns
ns
PD
Channel Switching Time
(Note 8)
t
20
300
80
SW
Switching Transient
V
INA
= V
= 0V, MAX463–MAX466
mV
P-P
INB
Amplifier Switching Off-Time
(Note 9)
t
MAX463–MAX466
ns
OFF
Amplifier Switching On-Time
(Note 10)
t
MAX463–MAX466
100
ns
ON
—–
—–
Logic Input High Threshold
Logic Input Low Threshold
Logic Input Current High
Logic Input Current Low
V
EN, A0, CS, LE; MAX463–MAX466
2
2
V
V
IH
—–
—–
V
EN, A0, CS, LE; MAX463–MAX466
—– —–
0.8
0.8
IL
I
EN, A0, CS, LE; MAX463–MAX466
—– —–
200
200
200
200
µA
µA
INHI
I
EN, A0, CS, LE; MAX463–MAX466
INLO
_______________________________________________________________________________________
3
Tw o -Ch a n n e l, Trip le /Qu a d
RGB Vid e o S w it c h e s a n d Bu ffe rs
ELECTRICAL CHARACTERISTICS (continued)
(V+ = 5V, V- = -5V, -2V ≤ V ≤ +2V, R
= 75Ω, unless otherwise noted.)
IN
LOAD
T
= +25°C
T
= T
MIN
to T
MAX
A
A
MIN MAX
PARAMETER
SYMBOL
CONDITIONS
UNITS
MIN TYP MAX
—–
—–
Address Setup Time (Note 11)
Address Hold Time (Note 11)
t
EN, A0, CS, LE; MAX463–MAX466
30
30
ns
ns
ns
SU
—–
—–
t
H
EN, A0, CS, LE; MAX463–MAX466
—– —–
0
0
—–
CS Pulse Width Low (Note 11)
t
CS
EN, A0, CS, LE; MAX463–MAX466
15
15
Note 1: Voltage gain accuracy for the unity-gain devices is defined as [(V
- V ) at V = 1V - (V
- V ) at V = -1V]/2.
OUT IN IN
OUT
IN
IN
Note 2: Voltage gain accuracy for the gain-of-two devices is defined as [(V
/2 - V ) at V = 1V - (V
/2 - V ) at V = -1V]/2.
OUT IN IN
OUT
IN
IN
Note 3: Tested with a 3.58MHz sine wave of amplitude 40IRE superimposed on a linear ramp (0IRE to 100IRE), R = 150Ω to ground.
L
Note 4: Tested with the selected input connected to ground through a 75Ω resistor, and a 4V sine wave at 10MHz driving adjacent input.
P-P
Note 5: Tested in the same manner as described in Note 4, but with all other inputs driven.
—–
Note 6: Tested with LE = 0V, EN = V+, and all inputs driven with a 4V , 10MHz sine wave.
P-P
Note 7: Measured from a channel switch command to measurable activity at the output.
Note 8: Measured from where the output begins to move to the point where it is well defined.
Note 9: Measured from a disable command to amplifier in a non-driving state.
Note 10: Measured from an enable command to the point where the output reaches 90% current out.
Note 11: Guaranteed by design.
63–MAX470
__________________________________________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
MAX468
MAX464
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
OUTPUT IMPEDANCE
vs. FREQUENCY
MAX468
GAIN AND PHASE RESPONSES
100
10
1
60
50
40
30
2
1
V–
GAIN
0
0
V+
PHASE
–1
36
72
0.1
108
144
180
20
10
–2
–3
0.01
10k
100k
1M
10M 100M
1G
1k
10k
100k
1M
10M 100M
10k
100k
1M
10M
100M
FREQUENCY (Hz)
FREQUENCY (Hz)
FREQUENCY (Hz)
4
_______________________________________________________________________________________
Tw o -Ch a n n e l, Trip le /Qu a d
RGB Vid e o S w it c h e s a n d Bu ffe rs
63–MAX470
____________________________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
MAX463
MAX465
DISABLED OUTPUT RESISTANCE
vs. TEMPERATURE
VOLTAGE GAIN ACCURACY
DISABLED OUTPUT RESISTANCE
vs. TEMPERATURE
vs. TEMPERATURE
400
350
300
0.16
1.30
1.25
1.20
0.14
MAX465
0.12
0.10
MAX463
250
200
1.15
1.10
0.08
0.06
–50 –25
0
25
50
75
100
–50 –25
0
25
50
75
100
–50 –25
0
25
50
75
100
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
DISABLED SUPPLY CURRENT
vs. TEMPERATURE
SUPPLY CURRENT PER AMPLIFIER
vs. TEMPERATURE
OUTPUT VOLTAGE SWING
vs. LOAD RESISTANCE
40
35
30
25
4
30
25
3
2
I+
I–
I+
I–
20
15
10
5
1
MAX463/4/7/8:V
IN
MAX465/6/9/70:V
IN
=
=
4V
2V
0
–1
–2
20
15
10
–3
–4
0
–50 –25
0
25
50
75
100
–50 –25
0
25
50
75
100
10
100
1000
10000
LOAD RESISTANCE (Ω)
TEMPERATURE (°C)
TEMPERATURE (°C)
_______________________________________________________________________________________
5
Tw o -Ch a n n e l, Trip le /Qu a d
RGB Vid e o S w it c h e s 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 )
(T = +25°C, unless otherwise noted.)
A
MAX464
MAX466
SMALL-SIGNAL STEP RESPONSE
SMALL-SIGNAL STEP RESPONSE
A: V ,
IN
A: V ,
IN
GND
GND
GND
GND
100mV/div
100mV/div
B: V
OUT
,
B: V ,
OUT
100mV/div
200mV/div
63–MAX470
10ns/div
10ns/div
MAX466
MAX464
LARGE-SIGNAL STEP RESPONSE
LARGE-SIGNAL STEP RESPONSE
GND
GND
GND
GND
A: V ,
IN
A: V ,
IN
1V/div
2V/div
B: V
,
OUT
B: V
,
OUT
2V/div
2V/div
20ns/div
20ns/div
MAX464
OUTPUT TRANSIENT WHEN SWITCHING
BETWEEN TWO GROUNDED INPUTS
MAX464
EN RESPONSE TIME
A: CS,
5V/div
A: CS,
5V/div
GND
GND
GND
GND
B: A0,
B: EN,
5V/div
5V/div
GND
GND
C: OUT0,
C: OUT3,
1V/div
100mV/div
50ns/div
50ns/div
t
t
ON
OFF
6
_______________________________________________________________________________________
Tw o -Ch a n n e l, Trip le /Qu a d
RGB Vid e o S w it c h e s a n d Bu ffe rs
63–MAX470
_____________________________________________________________P in De s c rip t io n s
PIN
NAME
IN0A
GND
FUNCTION
MAX463/MAX465 MAX464/MAX466
1
28
Channel A, Analog Input 0
Analog Ground
2, 4, 9,
11, 15, 24
1, 3, 5,
11, 13, 19
3
2
IN1A
IN2A
IN3A
V-
Channel A, Analog Input 1
Channel A, Analog Input 2
Channel A, Analog Input 3
5
4
–
6
6, 7, 19
7, 9, 21, 23
Negative Power-Supply Input. Connect to -5V. Thermal path.
Channel B, Analog Input 0
8
10
8
10
IN0B
IN1B
IN2B
IN3B
OUT3
OUT2
V+
Channel B, Analog Input 1
12
12
Channel B, Analog Input 2
–
14
Channel B, Analog Input 3
–
15
Buffered Analog Output 3
13
17
Buffered Analog Output 2
14, 17
16
16, 18
20
Positive Power-Supply Input. Connect to +5V.
Buffered Analog Output 1
OUT1
OUT0
18
22
Buffered Analog Output 0
–—–
—–
Chip-Select—latch control for the digital inputs. When CS is low, A0 and EN
–—–
CS
—–
20
24
input registers are transparent. When CS goes high, the A0 input register latches.
—–
—–
If LE is high, the EN input register also latches when CS goes high (see LE).
—–
Channel-Select Input. When CS is low, driving A0 low selects channel A
and driving A0 high selects channel B.
21
22
25
26
A0
—–
—–
—–
Buffer-Enable Input. When CS is low or LE is low, driving EN low enables
–—–
EN
all output buffers and driving EN high disables all output buffers.
—–
Digital Latch-Enable Input. When LE is low, the EN register is transparent;
—–
—–
23
27
LE
when LE is high, the EN register is transparent only when CS is low. Hard-
wire to V+ or GND for best crosstalk performance.
PIN
MAX467/MAX469 MAX468/MAX470
NAME
FUNCTION
1
1
IN0
GND
IN1
Analog Input 0
2, 7, 8, 9, 15
2, 7, 15
Analog Ground
3
3
Analog Input 1
4, 5, 12, 13
4, 5, 12, 13
V-
Negative Power-Supply Input. Connect to -5V. Thermal path.
Analog Input 2
6
6
IN2
–
8
IN3
Analog Input 3
–
9
OUT3
V+
Buffered Analog Output 3
Positive Power-Supply Input. Connect to +5V.
Buffered Analog Output 2
Buffered Analog Output 1
Buffered Analog Output 0
10
11
14
16
10
11
14
16
OUT2
OUT1
OUT0
_______________________________________________________________________________________
7
Tw o -Ch a n n e l, Trip le /Qu a d
RGB Vid e o S w it c h e s a n d Bu ffe rs
_______________De t a ile d De s c rip t io n
The MAX463–MAX470 have a bipolar construction,
which results in a typical channel input capacitance of
COAX
only 5pF, whether the channel is on or off. This low
input capacitance allows the amplifiers to realize full
AC performance, even with source impedances as
great as 250Ω. It also minimizes switching transients
b e c a us e the d riving s ourc e s e e s the s a me loa d
whether the channel is on or off. Low input capaci-
RT
RETURN
CURRENT
COAX
tance is critical, because it forms a single-pole RC low-
pa ss filte r with the output impe da nc e of the sig na l
sourc e , a nd this filte r c a n limit the syste m’s sig na l
bandwidth if the RC product becomes too large.
RT
RETURN
CURRENT
The MAX465/MAX466/MAX469/MAX470’s amplifiers are
internally configured for a gain of two, resulting in an over-
all gain of one at the cable output when driving back-ter-
minated coaxial cable (see the section Driving Coaxial
Cable). The MAX463/MAX464/MAX467/MAX468 are
internally configured for unity gain.
63–MAX470
Figure 1. Low-Crosstalk Layout. Return current from the
termination resistor does not flow through the ground plane.
Connect all V- pins to a large power plane. The V- pins
conduct heat away from the internal die, aiding thermal
dissipation.
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
To realize the full AC performance of high-speed ampli-
fiers, pay careful attention to power-supply bypassing
and board layout, and use a large, low-impedance
ground plane. With multi-layer boards, the ground
plane should be located on the layer that is not dedi-
cated to a specific signal trace.
Diffe re n t ia l Ga in a n d P h a s e Erro rs
Differential gain and phase errors are critical specifica-
tions for an amplifier/buffer in color video applications,
because these errors correspond directly to changes in
the color of the displayed picture in composite video
systems. The MAX467–MAX470 have low differential
gain and phase errors, making them ideal in broadcast-
quality composite color applications, as well as in RGB
video systems where these errors are less significant.
To prevent unwanted signal coupling, minimize the
tra c e a re a a t the c irc uit's c ritic a l hig h-imp e d a nc e
nodes, and surround the analog inputs with an AC
ground trace (analog ground, bypassed DC power
s u p p ly, e tc ). Th e a n a lo g in p u t p in s to th e
MAX463–MAX470 ha ve b e e n s e p a ra te d with AC
ground pins (GND, V+, V-, or a hard-wired logic input)
to minimize parasitic coupling, which can degrade
crosstalk and/or stability of the amplifier. Keep signal
paths as short as possible to minimize inductance,
and ensure that all input channel traces are of equal
length to maintain the phase relationship between the
R, G, and B signals. Connect the coaxial-cable shield
to the ground side of the 75Ω terminating resistor at
the g round p la ne to furthe r re d uc e c ros s ta lk (s e e
Figure 1).
The MAX467–MAX470 differential gain and phase errors
a re me a s ure d with the Te ktronix VM700 Vid e o
Measurement Set, with the input test signal provided by
the Tektronix 1910 Digital Generator as shown in Figure 2.
Me a s uring the d iffe re ntia l g a in a nd p ha s e of the
MAX469/MAX470 (Figure 2a) is straightforward because
the output amplifiers are configured for a gain of two,
allowing connection to the VM700 through a back-termi-
nated coaxial cable. Since the MAX467/MAX468 are
unity-gain devices, driving a back-terminated coax
would result in a gain of 1/2 at the VM700.
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 10µF tantalum or alu-
minum-electrolytic capacitors in parallel with the 0.1µF
ceramics. Keep capacitor lead lengths as short as
possible to minimize series inductance; surface-mount
(chip) capacitors are ideal.
Figure 2b shows a test method to measure the differen-
tial gain and phase for the MAX467/MAX468. First,
measure and store the video signal with the device
under test (DUT) removed and replaced with a short
circuit, and the 150Ω load resistor omitted. Then do
another measurement with the DUT and load resistor in
the circuit, and calculate the differential gain and phase
errors by subtracting the results.
8
_______________________________________________________________________________________
Tw o -Ch a n n e l, Trip le /Qu a d
RGB Vid e o S w it c h e s a n d Bu ffe rs
63–MAX470
75Ω CABLE
(a)
75Ω
MAX469/MAX470
75Ω CABLE
75Ω CABLE
75Ω
DUT
75Ω
SOURCE:
TEKTRONIX
75Ω
MEASUREMENT:
TEKTRONIX VM700
VIDEO MEASUREMENT
1910 DIGITAL GENERATOR
SET
MAX467/MAX468
(b)
75Ω CABLE
75Ω
75Ω CABLE
75Ω
A = 2
V
DUT
75Ω
150Ω
Figure 2. Differential Phase and Gain Error Test Circuits (a) for the MAX469/MAX470 Gain-of-Two Amplifiers, (b) for the
MAX467/MAX468 Unity-Gain Amplifiers
The MAX463–MAX470 phase margin and capacitive-
load driving performance are optimized by internal
compensation. When driving capacitive loads greater
than 50pF, connect an isolation resistor between the
amplifier output and the capacitive load, as shown in
Figure 3.
Drivin g Co a x ia l Ca b le
Hig h-s p e e d p e rforma nc e , e xc e lle nt outp ut c urre nt
capability, and an internally fixed gain of two make the
MAX465/MAX466/MAX469/MAX470 ideal for driving
50Ω or 75Ω b a c k-te rmina te d c oa xia l c a b le s . The
MAX465/MAX466/MAX469/MAX470 will drive a 150Ω
load (75Ω back-terminated cable) to ±2.5V.
The Typical Operating Circuit shows the MAX465/MAX466
driving four back-terminated 75Ω video cables. The
back-termination resistor (at each amplifier output) pro-
vides impedance matching at the driven end of the
cable to eliminate signal reflections. It forms a voltage
divider with the load impedance, which attenuates the
signal at the cable output by one-half. The amplifier
operates with an internal 2V/V closed-loop gain to pro-
vide unity gain at the cable’s output.
A = 1
V
12Ω
100pF
IN_
OUT_
Drivin g Ca p a c it ive Lo a d s
Driving large capacitive loads increases the likelihood
of oscillation in most amplifier circuits. This is especially
true for circuits with high loop-gains, like voltage follow-
ers. The amplifier’s output impedance and the capaci-
tive 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.
MAX468
Figure 3a. Using an Isolation Resistor with a Capacitive Load
_______________________________________________________________________________________
9
Tw o -Ch a n n e l, Trip le /Qu a d
RGB Vid e o S w it c h e s a n d Bu ffe rs
MAX468 (WITH ISOLATION RESISTOR)
MAX468 (NO ISOLATION RESISTOR)
A
B
A
B
GND
GND
GND
GND
1µs/div
= 12Ω
1µs/div
C
= 100pF
LOAD
C
= 100pF, R
ISOLATION
LOAD
A: V , 500mV/div
IN
A: V , 500mV/div
IN
63–MAX470
B: V , 500mV/div
OUT
B: V , 500mV/div
OUT
Figure 3b. Step Response without an Isolation Resistor
Figure 3c. Step Response with an Isolation Resistor
disabled MAX463/MAX464 outputs exhibit a 250kΩ
typical resistance. Because their internal feedback
resistors are required to produce a gain of two, the
MAX465/MAX466 exhibit a 1kΩ disabled output resis-
tance.
Dig it a l In t e rfa c e
The MAX463–MAX466 multiplexer architecture provides
an input transistor buffer, ensuring that no input chan-
nels are ever connected together. Select a channel by
changing A0's state (A0 = 0 for channel A, and A0 = 1
for channel B) and pulsing CS low (see Tables 1a, 1b).
—–
—–
—–
LE determines whether EN is latched by CS or operates
independently. When the latch-enable input (LE) is con-
Figure 4 shows the logic timing diagram.
—–
—–
—–
nected to V+, CS becomes the latch control for the EN
Output Disable (MAX463–MAX466)
—–
—–
input register. If CS is low, both the EN and A0 registers
When the enable input (EN) is driven to a TTL low state, it
—–
—–
are transparent; once CS returns high, both registers
enables the MAX463–MAX466 amplifier outputs. When EN
are latched.
is driven high, it disables the amplifier outputs. The
tCS
CS
tH
tSU
A0
tH
tSU
EN
tON
tOFF
HIGH-Z
OUTPUTS
tSW
LE = V+
tPD
Figure 4. Logic Timing Diagram
10 ______________________________________________________________________________________
Tw o -Ch a n n e l, Trip le /Qu a d
RGB Vid e o S w it c h e s a n d Bu ffe rs
63–MAX470
Table 1a. Amplifier and Channel Selection
with LE = V+
Table 1b. Amplifier and Channel Selection
with LE = GND
—–
—–
—–
—–
EN
CS
EN
A0
FUNCTION
CS
A0
FUNCTION
Enables amplifier outputs.
Selects channel A.
Enables amplifier outputs.
Selects channel A.
0
0
0
0
0
0
0
0
0
1
1
0
Enables amplifier outputs.
Selects channel B.
Enables amplifier outputs.
Selects channel B.
0
0
1
0
1
1
0
1
Disables amplifiers. Outputs high-Z.
A0 register = channel A
1
X
X
Disables amplifiers. Outputs high-Z.
Latches all input registers.
Changes nothing.
Disables amplifiers. Outputs high-Z.
A0 register = channel B
X
Enables amplifier outputs, latches A0
register, programs outputs to output A
1
1
0
1
X
X
or B, according to the setting of A0 at
—–
CS's last edge.
Disables amplifiers. Outputs high-Z.
—–
When LE is connected to ground, the EN register is
Another option for output disable is to connect LE to V+,
—–
transparent and independent of CS activity. This allows
all MAX463–MAX466 devices to be simultaneously shut
parallel the outputs of several MAX463-MAX466s, and use
—–
EN to individually disable all devices but the one in use
—–
down, regardless of the CS input state. Simply connect
—–
(Figure 5b).
LE to ground and connect all EN inputs together (Figure
When the outputs are disabled, the off isolation from
the analog inputs to the amplifier outputs is typically
5a). For the MAX464 and MAX466, LE must be hard-
wired to either V+ or ground (rather than driving LE with
a gate) to prevent crosstalk from the digital inputs to
IN0A.
70dB at 10MHz, all inputs driven with a 4V
sine
P-P
wave and a 150Ω load impedance. Figure 6 shows the
test circuits used to measure isolation and crosstalk.
EN
MAX463–
MAX466
AO
MAX463–
MAX466
LE
CS
+5V
LE
SHUTDOWN
EN
EN
AO
MAX463–
LE MAX466
MAX463–
MAX466
CS
+5V
LE
EN
NOTE: ISOLATION RESISTORS,
(a)
(b)
IF REQUIRED, NOT SHOWN.
–—–
–—–
Figure 5. (a) Simultaneous Shutdown of all MAX463–MAX466, (b) Enable (EN) Register Latched by CS
______________________________________________________________________________________ 11
Tw o -Ch a n n e l, Trip le /Qu a d
RGB Vid e o S w it c h e s a n d Bu ffe rs
MAX467–MAX470
MAX467–MAX470
150Ω
150Ω
75Ω
75Ω
V
IN
= 4V
P-P
AT 10MHz,
R = 75Ω
S
63–MAX470
*
*
V
IN
= 4V
P-P
AT 10MHz,
R = 75Ω
S
(a)
(b)
MAX463–MAX466
MAX463–MAX466
75Ω
150Ω
150Ω
150Ω
150Ω
150Ω
150Ω
150Ω
150Ω
*
*
LE
EN
+5V
V
IN
= 4V AT 10MHz,
P-P
V
= 4V AT 10MHz,
P-P
IN
R = 75Ω
S
R = 75Ω
S
(c)
(d)
* MAX464/MAX466/MAX468/MAX470 ONLY
Figure 6. (a) MAX467–MAX470 Adjacent Channel Crosstalk, (b) MAX467–MAX470 All-Hostile Crosstalk, (c) MAX463–MAX466
All-Hostile Off Isolation, (d) MAX463–MAX466 All-Hostile Crosstalk
12 ______________________________________________________________________________________
Tw o -Ch a n n e l, Trip le /Qu a d
RGB Vid e o S w it c h e s a n d Bu ffe rs
63–MAX470
75Ω
28
27
26
25
24
23
IN0A
1
2
3
4
5
6
GND
IN1A
LE
EN
A0
+5V
MAX470
75Ω
75Ω
75Ω
MAX464
GND
IN2A
CS
V–
–5V
OUT0 22
1
2
IN0
OUT0 16
GND
IN3A
75Ω
–5V
75Ω
75Ω
21
V–
15
GND
IN1
GND
7
8
V–
OUT1 20
3
OUT1 14
–5V
75Ω
–5V
IN0B
75Ω
75Ω
19
75Ω
75Ω
75Ω
4
5
13
V–
GND
9
–5V
–5V
V–
–5V
V–
18
12
+5V
V–
V–
V+
–5V
10
IN1B
OUT2 17
6
7
IN2
OUT2 11
75Ω
11
12
75Ω
+5V
75Ω
GND
IN2B
16
10
GND
IN3
V+
V+
V+
75Ω
OUT3 15
8
OUT3
9
13
GND
75Ω
75Ω
14 IN3B
75Ω
75Ω
28
27
26
25
24
23
IN0A
1
GND
LE
EN
A0
+5V
–5V
2
3
4
5
6
IN1A
75Ω
75Ω
75Ω
MAX464
GND
IN2A
CS
V–
OUT0 22
GND
IN3A
75Ω
–5V
21
V–
7
8
V–
OUT1 20
–5V
75Ω
–5V
IN0B
75Ω
19
GND
9
V–
18
+5V
V+
10
IN1B
OUT2 17
75Ω
75Ω
75Ω
11
12
75Ω
+5V
GND
IN2B
16
V+
OUT3 15
13
GND
75Ω
14 IN3B
FROM OTHER
MAX464s
Figure 7. Higher-Order RGB + Sync Video Multiplexer
______________________________________________________________________________________ 13
Tw o -Ch a n n e l, Trip le /Qu a d
RGB Vid e o S w it c h e s a n d Bu ffe rs
A1
A0
CS
75Ω
28
27
26
25
24
23
IN0A
1
2
3
4
5
6
GND
IN1A
LE
EN
A0
+5V
75Ω
75Ω
75Ω
MAX466
GND
IN2A
CS
V–
–5V
OUT0 22
GND
IN3A
22Ω
–5V
50Ω
75Ω
21
V–
7
8
V–
OUT1 20
–5V
75Ω
–5V
IN0B
22Ω
50Ω
50Ω
50Ω
19
75Ω
75Ω
75Ω
GND
9
V–
18
63–MAX470
+5V
V+
10
IN1B
OUT2 17
75Ω
11
12
22Ω
+5V
GND
IN2B
16
V+
75Ω
OUT3 15
13
GND
22Ω
14 IN3B
75Ω
75Ω
28
27
26
25
24
23
IN0A
1
GND
LE
EN
A0
+5V
–5V
2
3
4
5
6
IN1A
75Ω
75Ω
75Ω
MAX466
GND
IN2A
CS
V–
OUT0 22
GND
IN3A
22Ω
–5V
21
V–
7
8
V–
OUT1 20
–5V
75Ω
–5V
IN0B
22Ω
19
GND
9
V–
18
+5V
V+
10
IN1B
OUT2 17
75Ω
11
12
22Ω
+5V
GND
IN2B
16
V+
75Ω
75Ω
OUT3 15
13
GND
22Ω
14 IN3B
Figure 8. 1-of-4 RGB + Sync Video Multiplexer
14 ______________________________________________________________________________________
Tw o -Ch a n n e l, Trip le /Qu a d
RGB Vid e o S w it c h e s a n d Bu ffe rs
63–MAX470
P a ra lle lin g MAX4 6 6 s t o S w it c h
__________Ap p lic a t io n s In fo rm a t io n
1 -o f-4 RGB + S yn c S ig n a l In p u t s
Figure 8 shows a 1-of-4 RGB + sync video mux/amp
circuit. The 1kΩ disabled output resistance limits the
number of paralleled MAX465/MAX466s to no more
than two. The amplifier outputs are connected after a
22Ω isolation resistor and ahead of a 50Ω back-termi-
nation resistor, which isolates the active amplifier out-
put from the capacitive load (5pF typ) presented by the
inactive output of the second MAX466. Impedance
mismatching is minimal, and the signal gain at the
cable end is near 1. This minimizes ringing in the out-
put signals. For multiplexing more than two devices,
s e e the s e c tion Hig he r Ord e r RGB + Sync Vid e o
Multiplexing, above.
Hig h e r-Ord e r RGB + S yn c
Vid e o Mu lt ip le x in g
Higher-order RGB video multiplexers can be realized
by paralleling several MAX463/MAX464s. Connect LE
—–
—–
to V+ and use CS and EN to disable all devices but the
one in use. Since the disabled output resistance of the
MAX463/MAX464 is 250kΩ, several devices may be
paralleled to form larger RGB video multiplexer arrays
without signal degradation. Connect series resistors at
each amplifier's output to isolate the disabled output
c a p a c ita nc e of e a c h p a ra lle le d d e vic e , a nd us e a
MAX469 or MAX470 to drive the output coaxial cables
(see Figure 7).
_____________________________________________P in Co n fig u ra t io n s (c o n t in u e d )
TOP VIEW
GND
IN1A
GND
IN2A
GND
IN3A
V-
1
2
3
4
5
6
7
8
9
28 IN0A
27 LE
IN0
GND
IN1
V-
1
2
3
4
5
6
7
8
16 OUT0
15 GND
14 OUT1
13 V-
IN0
GND
IN1
V-
1
2
3
4
5
6
7
8
16 OUT0
15 GND
14 OUT1
13 V-
MAX464
MAX466
26 EN
25 A0
24 CS
V-
12 V-
V-
12 V-
23 V-
IN2
GND
GND
11 OUT2
10 V+
IN2
GND
IN3
11 OUT2
10 V+
22 OUT0
21 V-
IN0B
V-
9
GND
9
OUT3
20 OUT1
19 GND
18 V+
DIP/SO
DIP/SO
IN1B 10
GND 11
IN2B 12
GND 13
IN3B 14
MAX468
MAX470
QUAD
17 OUT2
16 V+
MAX467
MAX469
TRIPLE (RGB)
BUFFERS
BUFFERS
15 OUT3
DIP/SO
______________________________________________________________________________________ 15
Tw o -Ch a n n e l, Trip le /Qu a d
RGB Vid e o S w it c h e s a n d Bu ffe rs
__________Typ ic a l Op e ra t in g Circ u it
_Ord e rin g In fo rm a t io n (c o n t in u e d )
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
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
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
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
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
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
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
28 Narrow Plastic DIP
28 Wide SO
Dice*
MAX464CNI
MAX464CWI
MAX464C/D
MAX464ENI
MAX464EWI
MAX465CNG
MAX465CWG
MAX465C/D
MAX465ENG
MAX465EWG
MAX466CNI
MAX466CWI
MAX466C/D
MAX466ENI
MAX466EWI
MAX467CPE
MAX467CWE
MAX467C/D
MAX467EPE
MAX467EWE
MAX468CPE
MAX468CWE
MAX468C/D
MAX468EPE
MAX468EWE
MAX469CPE
MAX469CWE
MAX469C/D
MAX469EPE
MAX469EWE
MAX470CPE
MAX470CWE
MAX470C/D
MAX470EPE
MAX470EWE
+5V
MAX465
MAX466
10µF
0.1µF
28 Narrow Plastic DIP
28 Wide SO
A
= 2
V
IN0A
75Ω
75Ω
OUT0
OUT1
OUT2
OUT3
24 Narrow Plastic DIP
24 Wide SO
Dice*
IN0B
75Ω
A
V
= 2
= 2
= 2
IN1A
IN1B
24 Narrow Plastic DIP
24 Wide SO
28 Narrow Plastic DIP
28 Wide SO
Dice*
75Ω
75Ω
A
V
IN2A
IN2B
75Ω
75Ω
63–MAX470
28 Narrow Plastic DIP
28 Wide SO
A
V
IN3A
IN3B
A0
16 Plastic DIP
16 Wide SO
Dice*
75Ω
LOGIC
16 Plastic DIP
16 Wide SO
16 Plastic DIP
16 Wide SO
Dice*
-5V
MAX466
ONLY
10µF
0.1µF
16 Plastic DIP
16 Wide SO
16 Plastic DIP
16 Wide SO
Dice*
16 Plastic DIP
16 Wide SO
16 Plastic DIP
16 Wide SO
Dice*
16 Plastic DIP
16 Wide SO
* Dice are specified at T = +25°C, DC parameters only.
A
16 ______________________________________________________________________________________
相关型号：
©2020 ICPDF网 联系我们和版权申明