MAXIM MAX456C/D

19-2858; Rev 2; 2/94
8 x 8 Video Crosspoint Switch
________________________Applications
Video Test Equipment
____________________________Features
♦
♦
♦
♦
♦
♦
Routes Any Input Channel to Any Output Channel
Switches Standard Video Signals
Serial or Parallel Digital Interface
Expandable for Larger Switch Matrices
80dB All-Channel Off Isolation at 5MHz
8 Internal Buffers with:
250V/µs Slew Rate, Three-State Output Capability,
Power-Saving Disable Feature, 35MHz Bandwidth
______________Ordering Information
PART
TEMP. RANGE
0°C to +70°C
40 Plastic DIP
MAX456CQH
MAX456C/D
0°C to +70°C
0°C to +70°C
44 PLCC
Dice*
Ordering Information continued on last page.
* Dice are specified at TA = +25°C, DC parameters only.
_________________Pin Configurations
TOP VIEW
D1/SER OUT 1
40 V+
D0/SER IN 2
Video Security Systems
A2 3
Video Editing
A1 4
________Typical Application Circuit
39 OUT0
38 D2
MAX456
IN0 5
WR
LATCH
INPUT
SELECT
OR
SERIAL
I/O
75Ω
75Ω
MAX456
OUTPUT
SELECT
35 OUT2
IN1 7
MAX470
AV = 2
A2
A1
A0
34 V-
LOAD 8
33 OUT3
IN2 9
32 AGND
DGND 10
31 OUT4
IN3 11
30 AGND
DGND 12
29 OUT5
IN4 13
28 AGND
EDGE/LEVEL 14
27 OUT6
IN5 15
8X8
T-SWITCH
MATRIX
26 V+
V+ 16
D3
D2
D1/SER OUT
D0/SER IN
25 OUT7
IN6 17
24 CE
SER/PAR 18
23 CE
IN7 19
AV = 2
MAX470
37 OUT1
36 D3
A0 6
8 INPUT CHANNELS
PIN-PACKAGE
MAX456CPL
22 LATCH
V- 20
PLCC on last page
21 WR
DIP
________________________________________________________________ Maxim Integrated Products
Call toll free 1-800-998-8800 for free samples or literature.
1
MAX456
_______________General Description
The MAX456 is the first monolithic CMOS 8 x 8 video
crosspoint switch that significantly reduces component
count, board space, and cost. The crosspoint switch
contains a digitally controlled matrix of 64 T-switches
that connect eight video input signals to any, or all, output channels. Each matrix output connects to eight
internal, high-speed (250V/µs), unity-gain-stable buffers
capable of driving 400Ω and 20pF to ±1.3V. For applications requiring increased drive capability, the
MAX456 outputs can be connected directly to two
MAX470 quad, gain-of-two video buffers, which are
capable of driving 75Ω loads.
Three-state output capability and internal, programmable active loads make it feasible to parallel multiple
MAX456s and form larger switch matrices.
In the 40-pin DIP package, crosstalk (70dB at 5MHz) is
minimized, and board area and complexity are simplified by using a straight-through pinout. The analog
inputs and outputs are on opposite sides, and each
channel is separated by a power-supply line or quiet
digital logic line.
MAX456
8 x 8 Video Crosspoint Switch
ABSOLUTE MAXIMUM RATINGS
Total Supply Voltage (V+ to V-) ...........................................+12V
Positive Supply Voltage V+ Referred to AGND......-0.3V to +12V
Negative Supply Voltage V- Referred to AGND .....-12V to +0.3V
DGND Voltage.........................................................AGND ±0.3V
Buffer Short Circuit to Ground when
Not Exceeding Package Power Dissipation .............Indefinite
Analog Input Voltage ............................(V+ + 0.3V) to (V- - 0.3V)
Digital Input Voltage .............................(V+ + 0.3V) to (V- - 0.3V)
Input Current, Power On or Off
Digital Inputs.................................................................±20mA
Analog Inputs ...............................................................±50mA
Continuous Power Dissipation (TA = +70°C)
40-Pin Plastic DIP (derate 11.3mW/°C above +70°C)....889mW
40-Pin CERDIP (derate 20.0mW/°C above +70°C)....1600mW
44-Pin PLCC (derate 13.3mW/°C above +70°C) .......1066mW
Operating Temperature Ranges:
MAX456C _ _ ......................................................0°C to +70°C
MAX456E _ _ ...................................................-40°C to +85°C
Storage Temperature Range .............................-65°C to +160°C
Lead Temperature (soldering, 10 sec) ............................+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+ = 5.0V, V- = -5.0V, -1.3V ≤ V IN ≤ +1.3V; LOAD = +5V; internal load resistors on; AGND = DGND = 0V; T A = +25°C,
unless otherwise noted.)
PARAMETER
Input Voltage Range
Voltage Gain
Buffer Offset Voltage
Offset Voltage Drift
CONDITIONS
Internal load
resistors on, no
external load,
VIN = 0V to 1V
MIN
-1.3
TYP
MAX
1.3
TA = +25°C
0.99
1.0
1.01
TA = TMIN to TMAX
0.98
1.0
1.02
V/V
TA = +25°C
±7
TA = TMIN to TMAX
±12
TA = TMIN to TMAX
20
Operating Supply Voltage
Supply Current, All Buffers On
(No External Load)
Supply Current, All Buffers Off
±4.5
TA = +25°C
TA = TMIN to TMAX
1.5
TA = TMIN to TMAX
±4.5V to ±5.5V, DC measurement
TA = TMIN to TMAX
Internal load resistors off, all buffers
off, TA = TMIN to TMAX
TA = +25°C
250
TA = TMIN to TMAX
200
Buffer Output Voltage Swing
Internal load resistors on, no external load
±1.3
Digital Input Current
TA = TMIN to TMAX
50
±100
nA
600
765
IOH = -0.4mA
Ω
V
µA
Ω
2.4
Serial mode,
–——–
SER/PAR = 5V
mA
nA
0.8
IOL = 1.6mA
mA
dB
10
Input Logic High Threshold
2
400
V
±10
±1
Input Logic Low Threshold
SER OUT Output Logic High
64
±0.1
Output Impedance at DC
SER OUT Output Logic Low
3.0
4
Analog Input Current
Internal Amplifier Load Resistor
(LOAD Pin = 5V)
45
60
TA = +25°C
mV
µV/°C
±5.5
39
Power-Supply Rejection Ratio
Output Leakage Current
UNITS
V
V
V
0.4
4
_______________________________________________________________________________________
V
8 x 8 Video Crosspoint Switch
(V+ = 5.0V, V- = -5.0V, -1.3V ≤ V IN ≤ +1.3V, LOAD = +5V, internal load resistors on, AGND = DGND = 0V, T A = +25°C,
unless otherwise noted.)
PARAMETER
XDYNAMIC SPECIFICATIONS (Note 1)
CONDITIONS
Output-Buffer Slew Rate
Internal load resistors on, 10pF load
Single-Channel Crosstalk
5MHz, VIN = 2VP-P (Note 2)
All-Channel Crosstalk
MIN
TYP
MAX
UNITS
250
V/µs
70
dB
5MHz, VIN = 2VP-P (Notes 2, 3)
57
dB
All-Channel Off Isolation
5MHz, VIN = 2VP-P (Note 2)
80
dB
-3dB Bandwidth
10pF load, VIN = 2VP-P (Note 2)
35
MHz
Differential Phase Error
(Note 4)
1.0
deg
Differential Gain Error
(Note 4)
0.5
Input Noise
DC to 40MHz
0.3
Input Capacitance
All buffer inputs grounded
6
pF
Buffer Input Capacitance
Additional capacitance for each output buffer connected to channel input
2
pF
Output Capacitance
Output buffer off
7
pF
60
25
%
1.0
mVRMS
SWITCHING CHARACTERISTICS (Note 1)
(Figure 4, V+ = 5.0V, V- = -5.0V, -1.3V ≤ V IN ≤ +1.3V, LOAD = +5V, internal load resistors on, AGND = DGND = 0V,
TA = TMIN to TMAX, unless otherwise noted.)
PARAMETER
Chip-Enable to Write Setup
SYMBOL
tCE
CONDITIONS
MIN
0
TYP
MAX
UNITS
ns
Write Pulse Width High
tWH
80
ns
Write Pulse Width Low
tWL
80
ns
Data Setup
tDS
Data Hold
Parallel mode
240
32-bit serial mode
160
ns
tDH
0
ns
Latch Pulse Width
tL
80
ns
Latch Delay
tD
80
Switch Break-Before-Make Delay
tON - tOFF
LATCH Edge to Switch Off
tOFF
LATCH Edge to Switch On
tON
Note 1:
Note 2:
Note 3:
Note 4:
LATCH on
ns
15
ns
35
ns
50
ns
Guaranteed by design.
See Dynamic Test Circuits on page 11.
3dB typical crosstalk improvement when RS = 0Ω.
Input test signal: 3.58MHz sine wave of amplitude 40IRE superimposed on a linear ramp (0 to 100IRE). IRE is a unit of
video-signal amplitude developed by the International Radio Engineers. 140IRE = 1.0V.
_______________________________________________________________________________________
3
MAX456
ELECTRICAL CHARACTERISTICS
MAX456
8 x 8 Video Crosspoint Switch
______________________________________________________________Pin Description
PIN
NAME
FUNCTION
DIP
PLCC
—
1, 12, 23, 34
N.C.
1
2
D1/SER OUT
2
3
D0/SER IN
3, 4, 6
4, 5, 7
A2, A1, A0
5, 7, 9, 11,
13, 15, 17, 19
6, 8, 10, 13,
15, 17, 19, 21
IN0–IN7
8
9
LOAD
Asynchronous control line. When LOAD = 1, all the 400Ω internal active
loads are on. When LOAD = 0, external 400Ω loads must be used. The
buffers MUST have a resistive load to maintain stability.
10, 12
11, 14
DGND
Digital Ground Pins. Both DGND pins must have the same potential and
be bypassed to AGND. DGND should be within ±0.3V of AGND.
14
16
–————–
EDGE/LEVEL
When this control line is high, the 2nd-rank registers are loaded with the
rising edge of the LATCH line. If this control line is low, the 2nd-rank registers are transparant when LATCH is low, passing data directly from the
1st-rank registers to the decoders.
16, 26, 40
18, 29, 44
V+
18
20
——–
SER/PAR
20, 34
22, 38
V-
21
24
WR
22
25
LATCH
23
26
—–
CE
24
27
CE
25, 27, 29, 31,
33, 35, 37, 39
28, 30, 32, 35,
37, 39, 41, 43
OUT7-OUT0
28, 30, 32
31, 33, 36
AGND
36
40
D3
38
42
D2
No connect. Not internally connected.
——–
Parallel Data Bit D1 when SER/PAR = 0V. Serial Output for cascading
——–
multiple parts when SER/PAR = 5V.
——–
Parallel Data Bit D0 when SER/PAR = 0V. A Serial Input when
——–
SER/PAR = 5V.
Output Buffer Address Lines
Video lnput Lines
All V+ pins must be tied to each other and bypassed to AGND
separately (Figure 2).
5V = 32-Bit Serial, 0V = 7-Bit Parallel
Both V- pins must be tied to each other and bypassed to AGND
separately (Figure 2).
WRITE in the serial mode, shifts data in. In the parallel mode, WR loads
data into the 1st-rank registers. Data is latched on the rising edge.
–————–
If EDGE/LEVEL = 5V, data is loaded from the 1st-rank registers to the 2nd–————–
rank registers on the rising edge of LATCH. If EDGE/LEVEL = 0V, data is
loaded while LATCH = 0V. In addition, data is loaded during the execution
of parallel-mode functions 1011 through 1110, or if LATCH = 5V during the
execution of the parallel-mode "software-LATCH" command (1111).
–——
——
—————
—–
–—–
Chip Enable. When CE = 0V and CE = 5V, the WR line is enabled.
–—–
Chip Enable. When CE = 0V and CE = 5V, the WR line is enabled.
Output Buffers 7-0 (Note 1)
Analog Ground must be at 0.0V since the gain resistors of the buffers are
tied to these 3 pins.
–——–
Parallel Data Bit D3 when SER/ PAR = 0V. When D3 = 0V, D0-D2 specifies
the input channel to be connected to buffer. When D3 = 5V, then D0-D2
–——–
specify control codes. D3 is not used when SER/ PAR = 5V.
–——–
Parallel Data Bit D2 when SER/ PAR = 0V. Not used when
–——–
SER/ PAR = 5V.
Note 1: Buffer inputs are internally grounded with a 1000 or 1001 command from the D3-D0 lines. AGND must be at 0.0V since the
gain setting resistors of the buffers are internally tied to AGND.
4
_______________________________________________________________________________________
8 x 8 Video Crosspoint Switch
___________________Digital Interface
Output Buffers
The desired switch state can be loaded in a 7-bit parallel-interface mode or 32-bit serial-interface mode (see
Table 3 and Figures 4-6). All action associated with the
WR line occurs on its rising
edge.
The same is true for
–———
—–
the LATCH line if EDGE/LEVEL is high. Otherwise, the
second-rank–—
registers
update while LATCH is low
———–
(when EDGE/
–—– LEVEL is low). WR is logically ANDed with
CE and C E to allow active-high or active-low chip
enable.
The MAX456 video crosspoint switch consists of 64
T-switches in an 8 x 8 grid (Figure 1). The 8 matrix outputs are followed by 8 wideband buffers optimized for
driving 400Ω and 20pF loads. Each buffer has an
internal active load on the output that can be readily
shut off via the LOAD input (off when LOAD = 0V). The
shut-off is useful when two or more MAX456 circuits are
connected in parallel to create more input channels.
With more input channels, only one set of buffers can
be active and only one set of loads can be driven.
And, when active, the buffer must have either
1) an internal load, 2) the internal load of another buffer
in another MAX456, or 3) an external load.
Each MAX456 output can be disabled under logic control. When a buffer is disabled, its output enters a highimpedance state. In multichip parallel applications, the
disable function prevents inactive outputs from loading
lines driven by other devices. Disabling the inactive
buffers reduces power consumption.
The MAX456 outputs connect easily to MAX470 quad,
gain-of-two buffers when 75Ω loads must be driven.
Power-On RESET
The MAX456 has an internal power-on reset (POR) circuit that remains low for 5µs when power is applied.
POR also remains low if the total supply voltage is less
than 4V. The POR disables all buffer outputs at
power-up, but the switch matrix is not preset to any initial condition. The desired switch state should be programmed before the buffer outputs are enabled.
7-Bit Parallel Mode
In the parallel-interface mode, the 7 data bits A2-A0
and D3-D0 specify an output channel (A2-A0) and the
input channel to which it connects (D3-D0). The data is
loaded on the rising edge of WR. The 8 input channels
are selected by 0000 through 0111 (D3-D0). The
remaining 8 codes (1000-1111) control other MAX456
functions, as listed in Table 1.
32-Bit
–——– Serial-Interface Mode
In serial mode (SER/PAR = high), all first-rank registers
are loaded with data, making it unnecessary to specify
an output address (A2, A1, A0). The input data format
is D3-D0, starting with OUT0 and ending with OUT7 for
32 total bits. Only codes 0000 through 1010 are valid.
Code 1010 disables a buffer, while code 1001 enables
it. After data is shifted into the 32-bit first-rank register,
it is transferred to the second rank by the LATCH line
(see Table 2).
_______________________________________________________________________________________
5
MAX456
_______________Detailed Description
MAX456
8 x 8 Video Crosspoint Switch
Table 1. Parallel-Interface Mode Functions
A2-A0
D3-D0
FUNCTION
0000 to 0111
Selects
Output
Buffer,
OUT0
to
OUT7
Connect the buffer selected by A2-A0 to the input channel selected by D3-D0.
1000
Connect the buffer selected by A2-A0 to DGND. Note, if the buffer output is on, its output
is its offset voltage.
1011
Shut off the buffer selected by A2-A0, and retain 2nd-rank contents.
1100
Turn on the buffer selected by A2-A0, or restore the previously connected channel.
1101
Turn off all buffers, or leave 2nd-rank registers unchanged.
1110
Turn on all buffers, or restore the previously connected channels.
1111
Send a pulse to the 2nd-rank registers to load them with the contents of the 1st-rank
registers. When latch is held high, this "software-LATCH" command performs the same
function as pulsing LATCH low.
1001 and 1010
Do not use these codes in the parallel-interface mode. These codes are for the serialinterface mode only.
Table 2. Serial-Interface Mode Functions
D3-D0
0000 to 0111
6
FUNCTION
Connect the selected buffer to the input
channel selected by D3-D0.
1000
Connect the input of the selected buffer to
GND. Note, if the buffer output remains
on, its input is its offset voltage.
1001
Turn on the selected buffer and connect
its input to GND. Use this code to turn on
buffers after power is applied. The default
power-up state is all buffers disabled.
1010
Shut off the selected buffer at the specified channel, and erase data stored in the
2nd rank of registers. The 2nd rank now
holds the command word 1010.
1011 to 1111
Do not use these codes in the serial-interface mode. They inhibit the latching of the
2nd-rank registers, which prevents proper
data loading.
_______________________________________________________________________________________
8 x 8 Video Crosspoint Switch
IN2
IN4
IN3
IN5
IN6
IN7
MAX456
IN1
IN0
OUTPUT
BUFFERS
A=1
OUT0
400Ω
MAX456
8x8
SWITCH
MATRIX
LOAD
A=1
SER/PAR
2nd-RANK REGISTERS
LATCH
EDGE/LEVEL
1st-RANK REGISTERS
WR
CE
CE
V+
A1
A0
A2
D0/SER IN
OUT7
D2
400Ω
V- AGND DGND
D3
D1/SER OUT
Figure 1. MAX456 Functional Diagram
Table 3. Input/Output Line Configurations
SERIAL/
PARALLEL
D3
D2
D1
D0
A2-A0
H
X
X
Serial
Output
Serial Input
X
L
H
Parallel
Input
Parallel
Input
Parallel
Input
Output
Buffer
Address
Parallel Mode,
D0-D2 = Control Code
L
L
Parallel
Input
Parallel
Input
Parallel
Input
Output
Buffer
Address
Parallel Mode,
D0-D2 = Input Address
COMMENT
32-Bit Serial Mode
Note : X = Don't Care, H = 5V, L = 0V
_______________________________________________________________________________________
7
MAX456
8 x 8 Video Crosspoint Switch
________________Typical Application
Figure 2 shows a typical application of the MAX456 with
MAX470 quad, gain-of-two buffers at the outputs to
drive 75Ω loads. This application shows the MAX456
digital-switch control interface set up in the 7-bit parallel mode. The MAX456 uses 7 data lines and 2 control
lines (WR and LATCH). Two additional lines may be
needed to control CE and LOAD when using multiple
MAX456s.
The input/output information is presented to the chip at
A2-A0 and D3-D0 by a parallel printer port. The data is
stored in the 1st-rank registers on the rising edge of
WR. When the LATCH line goes high, the switch configuration is loaded into the 2nd-rank registers, and all 8
outputs enter the new configuration at the same time.
Each 7-bit word updates only one output buffer at a
time. If several buffers are to be updated, the data is
individually loaded into the 1st-rank registers. Then, a
single LATCH pulse is used to reconfigure all channels
simultaneously.
The short Basic program in Figure 3 loads programming
data into the MAX456 from any IBM PC or compatible.
It uses the computer’s “LPT1” output to interface to the
circuit, then automatically finds the address for LPT1
and displays a table of valid input values to be used.
The program does not keep track of previous commands, but it does display the last data sent to LPT1,
which is written and latched with each transmission.
MAX470
5 IN0
8-INPUT
VIDEO
CHANNELS
DB-25
14
18
19
20
21
22
23
24
25
1
2
3
4
5
6
7
8
7
9
11
13
15
17
19
22
21
2
1
38
36
6
4
3
OUT0 39
1 IN0
OUT0 16
37
35
33
31
29
27
25
24
14
8
40
26
3 IN1
6 IN2
8 IN3
AV = 2
OUT1 14
OUT2 11
OUT3 9
IN1
IN2
IN3
IN4
IN5
IN6
IN7
OUT1
OUT2
OUT3
OUT4
MAX456 OUT5
OUT6
OUT7
CE
EDGE/LEVEL
LOAD
LATCH
V+
WR
V+
D0/SER IN
D1/SER OUT
D2
D3
A0
A1
A2
AGND
DGND
VVCE
SER/PAR
V+
28, 30, 32
10, 12
20
34
23
18
16
+5V
V+
GND
10
75Ω
75Ω
V-
2,7,15 4,5,12,13
-5V
+5V
-5V
ALL BYPASS CAPACITORS 0.1µF CERAMIC
Figure 2. Typical Application Circuit
8
_______________________________________________________________________________________
8 x 8 Video Crosspoint Switch
MAX456
Figure 3. BASIC Program for Loading Data into the MAX456 from a PC Using Figure 2's Circuit
____________________________________________________________Timing Diagrams
A0-A2
VALID DATA N-1
VALID DATA N
D0-D3
tDS
tDH
tWL
tWH
WR
tD
tL
LATCH
Figure 4. Write Timing for Serial- and Parallel-Interface Modes
_______________________________________________________________________________________
9
MAX456
8 x 8 Video Crosspoint Switch
_______________________________________________Timing Diagrams (continued)
SEE FIGURE 4 FOR WR
AND LATCH TIMING
DATA (N)
DATA (N + 1)
DATA (N + 2)
WR
LATCH
FIRST-RANK REGISTER DATA
DATA (N)
SECOND-RANK REGISTER DATA
(EDGE/LEVEL = Low)
DATA (N)
SECOND-RANK REGISTER DATA
(EDGE/LEVEL = High)
DATA (N + 1)
DATA (N + 2)
DATA (N + 1)
DATA (N)
DATA (N + 1)
–——–
Figure 5. Parallel-Interface Mode Format (SER/ PAR = Low)
SEE TABLE 2 FOR
INPUT DATA
INPUT DATA FOR OUT1 TO OUT6
INPUT DATA FOR OUT0
SEE FIGURE 4 FOR WR
AND LATCH TIMING
0D3
0D2
0D1
0D0
1D3
1D2
INPUT DATA FOR OUT7
7D3
7D2
7D1
7D0
WR
LATCH
SECOND-RANK REGISTER DATA
(EDGE/LEVEL = Low)
SECOND-RANK REGISTER DATA
(EDGE/LEVEL = High)
–——–
Figure 6. 32-Bit Serial-Mode Interface Format (SER/PAR = High)
10
______________________________________________________________________________________
DATA VALID
DATA VALID
8 x 8 Video Crosspoint Switch
IN0
OUT0
VOUT
IN1
OUT1
VOUT
IN2
OUT2
VOUT
IN3 MAX456 OUT3
IN3 MAX456 OUT3
VOUT
IN4
OUT4
IN4
OUT4
VOUT
IN5
OUT5
IN5
OUT5
VOUT
IN6
OUT6
IN6
OUT6
VOUT
IN7
OUT7
IN7
OUT7
VOUT
LOAD
+5V
IN0
OUT0
IN1
OUT1
IN2
OUT2
LOAD
VOUT
+5V
VIN = 2Vp-p @ 5MHz
RS = 75Ω
VIN = 2Vp-p, SWEEP FREQUENCY
RS = 75Ω
-3dB Bandwidth (Notes 1-4)
7x
75Ω
All-Channel Off Isolation (Notes 1, 5-8)
IN0
OUT0
VOUT
IN0
OUT0
IN1
OUT1
VOUT
IN1
OUT1
IN2
IN2
OUT2
VOUT
VOUT
IN3 MAX456 OUT3
IN4
OUT4
VOUT
IN4
IN5
OUT5
VOUT
IN5
OUT5
IN6
OUT6
VOUT
IN6
OUT6
IN7
IN7
OUT7
LOAD
+5V
VIN = 2Vp-p @ 5MHz
RS = 75Ω
Single-Channel Crosstalk (Notes 1, 5, 9-11)
Note 1:
Note 2:
Note 3:
Note 4:
Note 5:
Note 6:
Note 7:
Note 8:
Note 9:
Note 10:
Note 11:
Note 12:
75Ω
OUT2
IN3 MAX456 OUT3
VOUT
OUT4
OUT7
LOAD
+5V
VIN = 2Vp-p @ 5MHz
RS = 75Ω
All-Channel Crosstalk (Notes 1, 5, 9, 11, 12)
Connect LOAD (pin 8) to +5V (internal 400Ω loads on at all outputs).
Program any one input to connect to any one output (see Table 1 or 2 for programming codes).
Turn on buffer at the selected output (see Table 1 or 2).
Drive the selected input with VIN, and measure VOUT at the -3dB frequency at the selected output.
Program each numbered input to connect to the same numbered output (IN0 to OUT0, IN1 to OUT1, etc.).
See Table 1 or 2 for programming codes.
Turn off all output buffers (see Table 1 or 2).
Drive all inputs with VIN and measure VOUT at any output.
Isolation (in dB) = 20log10 (VOUT/VIN).
Turn on all output buffers (see Table 1 or 2).
Drive any one input with VIN and measure VOUT at any undriven output.
Crosstalk (in dB) = 20log10 (VOUT/VIN).
Drive all but one input with VIN and measure VOUT at the undriven output.
______________________________________________________________________________________
11
MAX456
_______________________________________________________Dynamic Test Circuits
44 43 42 41 40
A0
7
39
OUT2
IN1
8
38
V-
LOAD
9
37
OUT3
36
AGND
35
OUT4
N.C. 12
34
N.C.
IN3 13
33
AGND
DGND 14
32
OUT5
IN4 15
31
AGND
EDGE/LEVEL 16
30
OUT6
IN5 17
29
V+
IN2 10
DGND 11
MAX456
OUT7
CE
CE
LATCH
WR
N.C.
V-
IN7
SER/PAR
V+
18 19 20 21 22 23 24 25 26 27 28
___________________Chip Topography
V+
IN6
SER/PAR
IN7
VWR
LATCH
CE
CE
OUT7
IN0
A1
A2
D0/SER IN
D1/SER OUT
V+
0.167"
OUT0
(4.242mm)
D2
OUT1
D3
V+
PLCC
PIN-PACKAGE
40 Plastic DIP
44 PLCC
40 CERDIP
AO
V+
1
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
IN5
EDGE/LEVEL
IN4
DGND
IN3
DGND
IN2
LOAD
IN1
N.C.
2
TEMP. RANGE
MAX456EPL
MAX456EQH
MAX456EJL
D3
D1/SER OUT
3
OUT1
D0/SER IN
4
D2
A2
5
OUT0
IN0
A1
PART
6
TOP VIEW
__Ordering Information (continued)
OUT6
AGND
OUT5
AGND
OUT4
AGND
OUT3
VOUT2
____Pin Configurations (continued)
IN6
MAX456
8 x 8 Video Crosspoint Switch
0.184"
(4.674mm)
TRANSISTOR COUNT: 3820;
SUBSTRATE CONNECTED TO V+.
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.
12 __________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 (408) 737-7600
© 1994 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.