MAX4584 [MAXIM]
Serially Controlled Audio/Video Switches; 串口控制音频/视频开关
| 型号： | MAX4584 |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Serially Controlled Audio/Video Switches |
| 文件： | 总12页 (文件大小：136K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-1521; Rev 0; 8/99
Serially Controlled
Audio/Video Switches
/MAX485
General Description
Features
♦ +2.7V to +5.5V Single-Supply Operation
♦ SPST and SPDT Switches
The MAX4584/MAX4585 serial-interface, programmable
switches are ideal for multimedia applications. Each
device contains one normally open (NO) single-pole/
single-throw (SPST) switch and one single-pole/double-
throw (SPDT) switch. The MAX4584/MAX4585 feature
65Ω on-resistance, 4Ω on-resistance matching
between channels, and 5Ω on-resistance flatness.
Additionally, they have off-isolation of -83dB at 20kHz
and -48dB at 10MHz, with crosstalk of -84dB at 20kHz
and -60dB at 10MHz.
♦ 65Ω (max) R
with +5V Supply
ON
♦ Audio Performance
-83dB Off-Isolation at 20kHz
-84dB Crosstalk at 20kHz
♦ Video Performance
-48dB Off-Isolation at 10MHz
-60dB Crosstalk at 10MHz
The MAX4584 uses a 2-wire I2C™-compatible serial
interface; the MAX4585 uses a 3-wire SPI™/QSPI™/
MICROWIRE™-compatible interface. Both devices are
available in a 10-pin µMAX package and are specified
for the extended-industrial (-40°C to +85°C) temperature
range.
♦ Serial Interface
2-Wire I2C Compatible (MAX4584)
3-Wire SPI/QSPI/MICROWIRE Compatible
(MAX4585)
Ordering Information
Applications
PART
TEMP. RANGE
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
10 µMAX
Cellular Phones and Accessories
Private Mobile Radios (PMRs)
PC Multimedia Audio/Video Routing
Industrial Equipment
MAX4584EUB
MAX4585EUB
10 µMAX
Set-Top Boxes
Video Conferencing
Pin Configuration/
Functional Diagram
High-End Audio Equipment
TOP VIEW
MAX4584
MAX4585
COM1
A (CS)
1
2
3
4
5
10 NO1A
9
8
7
6
NO1B
GND
SDA (DIN)
V+
COM2
NO2
SCL (SCLK)
µMAX
2
I C is a trademark of Philips Corp.
( ) ARE FOR MAX4585 ONLY.
SPI/QSPI are trademarks of Motorola, Inc.
MICROWIRE is a trademark of National Semiconductor Corp.
________________________________________________________________ Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.
Serially Controlled
Audio/Video Switches
ABSOLUTE MAXIMUM RATINGS
V+ to GND................................................................-0.3V to +6V
COM_ and NO_ _ to GND (Note 1) ..............-0.3V to (V+ + 0.3V)
A, CS, SDA, DIN, SCL, and SCLK to GND...............-0.3V to +6V
Continuous Current into Any Terminal.............................. 20mA
Peak Current into Any Terminal
Continuous Power Dissipation (T = +70°C)
A
µMAX (derate 4.1mW/°C above +70°C) .....................330mW
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10sec) .............................+300°C
(pulsed at 1ms, 10ꢀ duty cycle)................................. 40mA
ESD per Method 3015.7.......................................................>2kV
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.
Note 1: Signals on NO_ _ or COM_ exceeding V+ or ground are clamped by internal diodes. Limit forward-diode current to maximum
current rating.
ELECTRICAL CHARACTERISTICS—Single +5V Supply
(V+ = +5V 5ꢀ, T = T
to T , unless otherwise noted. Typical values are at T = +25°C.) (Note 2)
MAX A
A
MIN
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
ANALOG SWITCHES
/MAX485
V
V
_ _,
COM_
NO
Analog Signal Range (Note 3)
On-Resistance
0
V+
V
T
A
T
A
T
A
T
A
T
A
T
A
T
A
T
A
T
A
T
A
T
A
T
A
= +25°C
45
2
65
80
4
V+ = 4.75V,
R
V _ _ = 3V,
NO
Ω
Ω
ON
I
= 4mA
COM_
= T
to T
MIN
MAX
MAX
MAX
MAX
MAX
MAX
= +25°C
= T to T
On-Resistance
Match Between Channels
(Note 4)
V+ = 4.75V,
∆R
V _ _ = 3V,
NO
ON
I
= 4mA
COM_
5
MIN
= +25°C
= T to T
2
5
V+ = 4.75V;
On-Resistance
Flatness (Note 5)
R
V _ _ = 1V, 2V, 3V;
NO
Ω
FLAT
I
= 4mA
COM_
6.5
1
MIN
= +25°C
= T to T
-1
-10
-1
0.001
0.001
0.002
V+ = 5.25V;
NO_ _
I
_ _
NO (OFF)
V
V
_ _ = 1V, 4.5V;
nA
nA
nA
NO
Off-Leakage Current (Note 6)
= 4.5V, 1V
COM_
10
1
MIN
= +25°C
= T to T
V+ = 5.25V;
COM_
I
V _ _ = 1V, 4.5V;
NO
COM_(OFF)
Off-Leakage Current (Note 6)
V
COM_
= 4.5V, 1V
-10
-1
10
1
MIN
V+ = 5.25V;
V _ _ = 1V, 4.5V, or
NO
floating;
= +25°C
= T to T
COM_
I
COM_(ON)
On-Leakage Current (Note 6)
-10
10
MIN
V
COM_
= 1V, 4.5V
AUDIO PERFORMANCE
V
= 1V
, f = 20kHz,
A
L
RMS IN
Off-Isolation (Note 7)
V
-83
-84
dB
dB
ISO(A)
R = 600Ω, Figure 8
V
A
= 1V
, f = 20kHz,
RMS IN
Channel-to-Channel Crosstalk
V
CT(A)
R = 600Ω, Figure 8
S
2
_______________________________________________________________________________________
Serially Controlled
Audio/Video Switches
/MAX485
ELECTRICAL CHARACTERISTICS—Single +5V Supply (continued)
(V+ = +5V 5ꢀ, T = T
to T , unless otherwise noted. Typical values are at T = +25°C.) (Note 2)
MAX A
A
MIN
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
VIDEO PERFORMANCE
V
= 1V
, f = 10MHz,
A
L
RMS IN
Off-Isolation (Note 7)
V
-48
-60
dB
dB
ISO(V)
R = 50Ω, Figure 8
V
A
= 1V
, f = 10MHz,
RMS IN
Channel-to-Channel Crosstalk
V
CT(V)
R = 50Ω, Figure 8
S
-0.1dB Bandwidth
-3dB Bandwidth
BW
BW
R = 75Ω, R = 1kΩ
5
300
5
MHz
MHz
pF
S
L
R = 50Ω, R = 50Ω
S
L
NO_ _ Off-Capacitance
C
OFF
f
IN
= 1MHz
DYNAMIC TIMING (Notes, 8, 11, and Figure 5)
V
= 2.5V,
T
A
T
A
T
A
T
A
= +25°C
275
125
400
500
200
250
NO_ _
L
L
Turn-On Time
Turn-Off Time
t
C = 35pF,
R = 5kΩ
ns
ns
ON
= T
to T
MIN
MAX
V
NO_ _
= 2.5V,
= +25°C
= T to T
t
C = 35pF,
R = 300Ω
OFF
L
L
MIN
MAX
Break-Before-Make Time
Charge Injection
t
V
= 2.5V, Figure 6
10
50
3
ns
BBM
NO_ _
Q
C = 1.0nF, V = 0, R = 0, Figure 7
pC
L
S
S
POWER SUPPLY
Power-Supply Voltage Range
Supply Current
V+
I+
2.7
5.5
10
V
All logic inputs = 0 or V+
5
µA
_______________________________________________________________________________________
3
Serially Controlled
Audio/Video Switches
ELECTRICAL CHARACTERISTICS—Single +3V Supply
(V+ = +3.0V 10ꢀ, T = T
A
to T , unless otherwise noted. Typical values are at T = +25°C.)
MAX A
MIN
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
ANALOG SWITCHES
V
V
,
NO_ _
Analog Signal Range (Note 3)
0
V+
V
COM_
V+ = 2.7V,
T
= +25°C
65
3
110
130
5
A
On-Resistance
R
ON
V
NO_ _
= 1V,
Ω
I
= 4mA
T = T
A
to T
COM_
MIN
MAX
MAX
MAX
MAX
MAX
On-Resistance
Match Between Channels
(Note 4)
V+ = 2.7V,
T = +25°C
A
∆R
V
NO_ _
= 1V,
Ω
Ω
ON
I
= 4mA
T = T to T
A MIN
6
COM_
V+ 2.7V;
T
A
= +25°C
3
10
12
1
=
On-Resistance
Flatness (Note 5)
R
FLAT
V
1V, 1.5V, 2V;
NO_ _ =
I
= 4mA
T = T
A
to T
COM_
MIN
/MAX485
V+ = 3.6V;
T
A
= +25°C
-1
-10
-1
0.001
0.001
NO_ _ Off-Leakage
Current (Notes 6, 9)
I
V
V
_ = 0.5V, 3V;
nA
nA
NO_ _(OFF)
COM
= 3V, 0.5V
T = T to T
A MIN
10
1
NO_ _
V+ = 3.6V;
T = +25°C
A
COM_ Off-Leakage
Current (Notes 6, 9)
I
_
V _ = 0.5V, 3V;
COM
COM (OFF)
V
NO_ _
= 3V, 0.5V
T = T to T
A MIN
-10
10
V+ = 3.6V;
T
A
= +25°C
-1
0.002
1
COM _ On-Leakage
Current (Notes 6, 9)
V
COM_
= 0.5V, 3V;
I
_
nA
COM (ON)
V
_ _ = 0.5V, 3V,
NO
T = T
to T
-10
10
A
MIN
MAX
or floating
AUDIO PERFORMANCE
V
= 0.5V
, f = 20kHz, R = 600Ω,
A
RMS IN L
Off-Isolation (Note 7)
V
-83
-84
dB
dB
ISO(A)
Figure 8
V
A
= 0.5V
, f = 20kHz, R = 600Ω,
S
RMS IN
Channel-to-Channel Crosstalk
VIDEO PERFORMANCE
Off-Isolation
V
CT(A)
Figure 8
V
A
= 0.5V
, f = 10MHz, R = 50Ω,
RMS IN L
V
-48
-60
dB
dB
ISO(V)
Figure 8
V
A
= 0.5V
, f = 10MHz, R = 50Ω,
RMS IN
S
Channel-to-Channel Crosstalk
V
CT(V)
Figure 8
-3dB Bandwidth
BW
R = 50Ω, R = 50Ω
200
5
MHz
pF
S
L
NO_ _ Off-Capacitance
C
OFF
f
IN
= 1MHz
DYNAMIC TIMING (Notes 8, 11, and Figure 5)
T
= +25°C
400
200
100
800
1000
350
A
V
= 1.5V,
NO_ _
L
Turn-On Time
t
ns
ON
R = 5kΩ, C = 35pF
L
T = T
A
to T
MIN
MAX
T
A
= +25°C
V
NO_ _
= 1.5V,
Turn-Off Time
t
ns
ns
OFF
R = 300Ω, C = 35pF
L
L
T = T
A
to T
500
MIN
MAX
Break-Before-Make Time
t
V
NO_ _
= 1.5V, Figure 6
10
BBM
4
_______________________________________________________________________________________
Serially Controlled
Audio/Video Switches
/MAX485
I/O INTERFACE CHARACTERISTICS
(V+ = +2.7V to +5.25V, T = T
A
to T , unless otherwise noted. Typical values are at T = +25°C.)
MAX A
MIN
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DIGITAL INPUTS (SCLK, DIN, CS, SCL, SDA, A)
V+ = 5V
V+ = 3V
V+ = 5V
V+ = 3V
0.8
0.6
Input Low Voltage
Input High Voltage
V
V
V
IL
3
2
V
IH
Input Hysteresis
V
0.2
0.01
5
V
HYST
Input Leakage Current
Input Capacitance
I
Digital inputs = 0 or V+
-1
1
µA
pF
LEAK
C
IN
DIGITAL OUTPUT (SDA)
Output Low Voltage
V
OL
I
= 6mA
0.4
V
SINK
2-WIRE TIMING CHARACTERISTICS
(Figures 1 and 2, V+ = +2.7V to +5.25V, f
= 100kHz, T = T
to T
, unless otherwise noted. Typical values are at
MAX
SCL
A
MIN
T
= +25°C.)
A
PARAMETER
SYMBOL
CONDITIONS
V+ = 2.7V to 5.25V
V+ = 4.75V to 5.25V
MIN
TYP
MAX
100
UNITS
0
SCL Clock Frequency
f
kHz
SCL
400
Bus Free Time Between Stop
and Start Conditions
t
4.7
µs
BUF
Hold Time After Start Condition
Stop Condition Setup Time
Data Hold Time
t
t
The first clock is generated after this period.
4.0
4.0
0
µs
µs
µs
ns
µs
µs
HD:STA
SU:STO
HD:DAT
t
Data Setup Time
t
250
4.7
4.0
SU:DAT
Clock Low Period
t
LOW
Clock High Period
t
HIGH
20 +
SCL/SDA Rise Time (Note 10)
SCL/SDA Fall Time (Note 10)
t
ns
ns
300
300
R
0.1C
B
20 +
0.1C
t
F
B
_______________________________________________________________________________________
5
Serially Controlled
Audio/Video Switches
3-WIRE TIMING CHARACTERISTICS
(Figures 3 and 4, V+ = +2.75V to +5.25V, f
= 2.1MHz, T = T
to T
, unless otherwise noted. Typical values are at
MAX
OP
A
MIN
T
A
= +25°C.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
2.1
10
UNITS
V+ = 2.7V to 5.25V
V+ = 4.75V to 5.25V
0
Operating Frequency
f
MHz
OP
DIN to SCLK Setup
t
100
0
ns
ns
ns
ns
ns
ns
µs
µs
ns
DS
DIN to SCLK Hold
t
DH
t
t
100
0
CS Fall to SCLK Rise Setup
CS Rise to SCLK Hold
SCLK Pulse Width Low
SCLK Pulse Width High
Rise Time (SCLK, DIN, CS)
Fall Time (SCLK, DIN, CS)
CS Pulse Width High
CSS
CSH
t
200
200
CL
t
CH
t
R
2
2
t
F
t
40
CSW
Note 2: Algebraic convention is used in this data sheet; the most negative value is shown in the minimum column.
Note 3: Guaranteed by design. Not subject to production testing.
/MAX485
Note 4: ∆R
= R
- R
.
ON
ON(MAX)
ON(MIN)
Note 5: Resistance flatness is defined as the difference between the maximum and minimum on-resistance values, as measured
over the specified analog signal range.
Note 6: Leakage parameters are 100ꢀ tested at maximum rated temperature and guaranteed by correlation at T = +25°C.
A
Note 7: Off-isolation = 20 log (V
_ / V _ _), V
_ = output, V _ _ = input to off switch.
COM NO
COM
NO
Note 8: All timing is measured from the clock’s falling edge preceding the ACK signal for 2-wire and from the rising edge of CS for
3-wire. Turn-off time is defined at the output of the switch for a 0.5V change, tested with a 300Ω load to ground. Turn-on
time is defined at the output of the switch for a 0.5V change and measured with a 5kΩ load resistor to GND. All timing is
shown with respect to 20ꢀ V+ and 70ꢀ V+, unless otherwise noted.
Note 9: Leakage testing is guaranteed by testing with a +5.25V supply.
Note 10: C = capacitance of one bus line in pF. Tested with C = 400pF.
B
B
Note 11: Typical values are for MAX4584 devices.
Typical Operating Characteristics
(V+ = +5V, T = +25°C, unless otherwise noted.)
A
ON-RESISTANCE
AND TEMPERATURE (V+ = 3.3V)
ON-RESISTANCE
ON-RESISTANCE
AND TEMPERATURE (V+ = 5V)
vs. V
vs. V
AND SUPPLY VOLTAGE
vs. V
COM
COM
COM
75
70
65
60
55
50
45
40
35
30
70
65
60
55
50
45
40
35
30
55
50
T
= +125°C
V+ = 2.7V
A
T
= +125°C
A
T
= +85°C
A
T
= +85°C
A
V+ = 3.0V
T
= +25°C
V+ = 4.0V
V+ = 5.0V
A
45
40
35
30
T
= +25°C
A
T
= -40°C
A
T = -55°C
A
T
= -40°C
A
V+ = 5.5V
T
= -55°C
A
1.5
3.0
0.5
1.0
2.0
2.5
0
3
4
5
0
1
2
3
4
5
0
1
2
V (V)
COM
V
COM
(V)
V
COM
(V)
6
_______________________________________________________________________________________
Serially Controlled
Audio/Video Switches
/MAX485
Typical Operating Characteristics (continued)
(V+ = +5V, T = +25°C, unless otherwise noted.)
A
SUPPLY CURRENT
vs. TEMPERATURE
TURN-ON/TURN-OFF TIMES
vs. SUPPLY VOLTAGE
CHARGE INJECTION
vs. V
COM
5.0
700
600
500
400
300
200
100
0
3
2
4.9
4.8
4.7
4.6
4.5
4.4
4.3
4.2
4.1
4.0
1
0
t
ON
-1
-2
-3
-4
t
OFF
-55 -35 -15
5
25 45 65 85 105 125
2.5
3.0
3.5
4.0
4.5
5.0
5.5
0
1
2
3
4
5
TEMPERATURE (°C)
SUPPLY VOLTAGE (V)
V
COM
(V)
TURN-ON/TURN-OFF TIMES
vs. TEMPERATURE
ON-LEAKAGE CURRENT
vs. TEMPERATURE
OFF-LEAKAGE CURRENT
vs. TEMPERATURE
350
300
250
200
150
100
50
10
1
10
I
V
V
AT
COM (OFF)
I
COM (ON)
AT
= 4.5V
COM
V
V
= 1.0V
= 1.0V
COM
= FLOAT
NO
NO
1
I
AT
COM (OFF)
t
ON
V
COM
= 1.0V
V
= 4.5V
NO
I
V
V
AT
COM (ON)
I
V
V
AT
NO (OFF)
0.1
0.1
= 4.5V
COM
= 4.5V
NO
= FLOAT
NO
= 1.0V
COM
t
OFF
I
V
V
AT
NO (OFF)
= 1.0V
0.01
0.01
NO
COM
= 4.5V
0
0.001
0.001
-55 -35 -15
5
25 45 65 85 105 125
25 45
TEMPERATURE (°C)
85
25 45
85
105 125
-55 -35 -15
5
65
-55 -35 -15
5
65
105 125
TEMPERATURE (°C)
TEMPERATURE (°C)
AUDIO FREQUENCY RESPONSE
VIDEO FREQUENCY RESPONSE
TURN-ON/TURN-OFF TIMES
0
0
600Ω IN AND OUT
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
-10
-20
INSERTION LOSS
CLK
5V/div
-30
-40
OFF-ISOLATION
CROSSTALK
t
ON
-50
-60
2V/div
-70
-80
OFF-ISOLATION
CROSSTALK
t
OFF
2V/div
-90
50Ω IN AND OUT
-100
TIME (100ns/div)
0.01
0.1
1
10
100
0.1
1
10
100
FREQUENCY (MHz)
FREQUENCY (MHz)
_______________________________________________________________________________________
7
Serially Controlled
Audio/Video Switches
Pin Description
PIN
NAME
FUNCTION
MAX4584
MAX4585
1
2
1
—
2
COM1
A
Analog Switch SPDT Common Terminal
LSB+2 of the 2-Wire Serial-Interface Address Field
Chip Select of the 3-Wire Serial Interface
Data Input of the 2-Wire Serial Interface
Data Input of the 3-Wire Serial Interface
Supply Voltage
—
3
CS
—
3
SDA
DIN
—
4
4
V+
5
—
5
SCL
SCLK
NO2
COM2
GND
NO1B
NO1A
Clock Input of the 2-Wire Serial Interface
Clock Input of the 3-Wire Serial Interface
Normally Open SPST Terminal
Analog Switch SPST Common Terminal
Ground
—
6
6
7
7
8
8
9
9
Normally Open Terminal
/MAX485
10
10
Normally Open Terminal
70%
70%
20%
70%
20%
70%
20%
70%
20%
SDA
SCL
20%
t
BUF
t
,
t ,
SU STA
SU DAT
t
,
HD STA
t
,
SU STO
t
t ,
HD DAT
LOW
70%
20%
70%
20%
70%
20%
70%
70%
70%
t
HIGH
t
,
HD STA
t
R
t
F
START CONDITION
REPEATED START CONDITION
STOP CONDITION START CONDITION
Figure 1. 2-Wire Serial-Interface Timing Diagram
ness. Audio off-isolation is -83dB at 20kHz, and
crosstalk is at least -84dB at 20kHz. Video off-isolation
is -48dB at 10MHz, and crosstalk is at least -60dB at
10MHz.
_______________Detailed Description
The MAX4584/MAX4585 are serial-interface, program-
mable switches. Each device contains one normally
open (NO) single-pole/single-throw (SPST) switch and
one single-pole/double-throw (SPDT) switch. The
switches are independently controlled through the on-
__________Applications Information
2
Switch Control
The MAX4584/MAX4585 have a common command-bit
structure; the only difference between them is the inter-
face type (2-wire or 3-wire, respectively).
chip serial interface. The MAX4584 uses a 2-wire I C-
compatible serial communications protocol; the
MAX4585 uses a 3-wire SPI/QSPI/MICROWIRE-com-
patible serial communications protocol.
The command controls the open/closed states of the
various switches. Table 1 shows the configuration of
the data bits and their related switches. After a com-
mand is issued, a logic “1” in any data-bit location clos-
These devices operate from a single +2.7V to +5.5V
supply and are optimized for use with an audio fre-
quency of 20kHz and video frequencies up to 10MHz.
They feature 65Ω on-resistance, 4Ω on-resistance
matching between channels, and 5Ω on-resistance flat-
8
_______________________________________________________________________________________
Serially Controlled
Audio/Video Switches
/MAX485
Table 1. Command-Bit Mapping
Table 2. Truth Table
LOGIC
NO1_ AND NO2
OPEN
COMMAND
POWER-UP
STATE
SWITCH
TERMINALS
BIT
0
1
D7 (MSB)
D6
X
—
—
X
CLOSED
X
X
D5
X
—
X
X
D4
X
—
Table 3. Address Bit Map
D3
X
—
X
D2
NO2 to COM2
NO1B to COM1
6, 7
9, 1
10, 1
0 (Open)
1 (Closed)
0 (Open)
ADDRESS BIT (A)
ADDRESS
0110 1010
0110 1110
D1
0
1
D0 (LSB) NO1A to COM1
X = Don’t care
COMMAND BYTE
SLAVE ADDRESS BYTE
SDA
MSB
MSB
LSB ACK
LSB
ACK
SCL
START CONDITION
STOP CONDITION
Figure 2. A Complete 2-Wire Serial-Interface Transmission
es the associated switch (Table 2). A logic “0” in any
data-bit location opens the associated switch.
the recognition of its address by pulling the SDA line
low for one clock period after the address byte is trans-
mitted. The slave device also issues a similar acknowl-
edgment after the command byte.
2-Wire Serial Interface
The MAX4584 uses a 2-wire I2C-compatible serial inter-
face. The COM_ register uses the “SendByte” protocol,
which consists of an address byte followed by a com-
mand byte (Table 1).
Start and Stop Conditions
The bus master signals the beginning of a transmission
with a start condition by transitioning SDA from high to
low while SCL is high. When the bus master has fin-
ished communicating with the slave device, it issues a
stop condition by transitioning SDA from low to high
while SCL is high. The bus is then free for another
transmission.
To address a given IC, bit A in the address byte must
duplicate the value present at the A pin of that IC. The
rest of the address bits must match those shown in
Table 3. The command byte details are described in
the Switch Control section.
The 2-wire serial interface requires only two I/O lines of
a standard microprocessor (µP) port. Figures 1 and 2
detail the timing diagram for signals on the 2-wire bus,
and Tables 1 and 3 detail the format of the signals. The
MAX4584 is a receive-only device and must be con-
trolled by the bus master device. A bus master device
communicates by transmitting the address byte of the
slave device over the bus and then transmitting the
desired information. Each transmission consists of a
start condition, an address byte, a command byte, and
finally a stop condition. The slave device acknowledges
Slave Address (Address Byte)
The MAX4584 uses an 8-bit-long slave address. To
select a slave address, connect A to V+ or GND. The
MAX4584 has two possible slave addresses, so a maxi-
mum of two of these devices may share the same
address line. The slave device MAX4584 monitors the
serial bus continuously, waiting for a start condition fol-
lowed by an address byte. When a slave device recog-
nizes its address (01101A10), it acknowledges that it is
ready for further communication by pulling the SDA line
low for one clock period.
_______________________________________________________________________________________
9
Serially Controlled
Audio/Video Switches
70%
20%
CS
20%
CSH
t
CSW
t
t
CSO
t
CL
t
CH
t
CSS
70%
70%
70%
SCLK
20%
DH
20%
20% 20%
20%
t
t
DS
D7
D6
D1
D0
DIN
Figure 3. 3-Wire Serial-Interface Timing Diagram
/MAX485
Addressable Serial Interface
SWITCHES UPDATED
To program several MAX4585s individually using a sin-
gle µP, connect DIN of each MAX4585 together and
control CS on each MAX4585 separately. To select a
particular device, drive the corresponding CS low,
clock in the 8-bit command, then drive CS high to exe-
cute the command. Typically, only one MAX4585 is
addressed at a time.
CS
SCLK
DATA CLOCKED IN
DIN
Power-Up State
The MAX4584/MAX4585 feature a preset power-up
state. See Table 1 to determine the power-up state of
these devices.
D7
D6 D5 D4 D3 D2 D1 D0
LSB
MSB
INPUT DATA BITS
___________________Chip Information
Figure 4. A Complete 3-Wire Serial Transmission
TRANSISTOR COUNT: 2259
3-Wire Serial Interface
The MAX4585 3-wire serial interface is SPI/
QSPI/MICROWIRE compatible. An active-low chip-
select (CS) input enables the device to receive data for
the serial input (DIN). Data is clocked in on the rising
edge of the serial-clock (SCLK) signal. A total of 8 bits
are needed in each write cycle. The first bit clocked
into the MAX4585 is the command byte’s MSB; the last
bit clocked in is the data byte’s LSB. The first 5 bits of
the command byte are “don’t care.” While shifting data,
the device remains in its original configuration. After all
8 bits are clocked into the input shift register, a rising
edge on CS latches the data into the MAX4585’s inter-
nal registers, initiating the device’s change of state.
Figures 3 and 4 detail the 3-wire protocol, and Table 1
details the command byte format.
10 ______________________________________________________________________________________
Serially Controlled
Audio/Video Switches
/MAX485
Test Circuits/Timing Diagrams
ACKNOWLEDGE
BIT
MAX4584
MAX4585
3V
t
R
< 20ns
50%
SCL
V
t < 20ns
F
0
V+
V+
10nF
OUT
2-WIRE
0.5V
0
t
ON
COM_
NO__
V
IN
V
OUT
V
OUT
V
OUT
- 0.5V
0
C
R
L
L
t
OFF
35pF
2 OR 3
DECODER/
CONTROLLER
SERIAL
INTERFACE
µP
3V
0
CS
50%
V
V
OUT
0
GND
0.5
3-WIRE
t
ON
C INCLUDES FIXTURE AND STRAY CAPACITANCE.
L
OUT
OUT
0
V
= V [R / (R + R )]
V
OUT
- 0.5
IN
L
L
ON
t
OFF
Figure 5. Switching Time
ACKNOWLEDGE
BIT
SCL
3V
t
< 20ns
R
F
50%
t < 20ns
0V
MAX4584
MAX4585
V
OUT
80%
V+
V+
10nF
2-WIRE
NO__
COM_
COM_
0
V
IN
V
OUT
t
BBM
NO__
2 OR 3
CS
3V
R
L
C
L
DECODER/
CONTROLLER
SERIAL
INTERFACE
µP
50%
V
OUT
GND
80%
3-WIRE
C INCLUDES FIXTURE AND STRAY CAPACITANCE.
L
V
= V
[R / (R + R )]
OUT
COM L L ON
0
t
BBM
Figure 6. Break-Before-Make Interval
______________________________________________________________________________________ 11
Serially Controlled
Audio/Video Switches
Test Circuits/Timing Diagrams (continued)
MAX4584
MAX4585
ACKNOWLEDGE
BIT
ACKNOWLEDGE
BIT
V+
V+
10nF
3V
0
SCL
NO_
COM_
2-WIRE
V
OUT
V
OUT
∆V
OUT
C
L
1000pF
2 OR 3
DECODER/
µP
CONTROLLER
SERIAL
INTERFACE
3V
0
CS
GND
/MAX485
3V
0
3-WIRE
DIN
8-BIT COMMAND
∆V
OUT
IS THE MEASURED VOLTAGE DUE TO CHARGE
TRANSFER ERROR Q WHEN THE CHANNEL TURNS OFF.
Q = ∆V • C
∆V
V
OUT
OUT
OUT
L
Figure 7. Charge Injection
MAX4584
MAX4585
V+
V+
10nF
V+
V+
10nF
NO__
ANALYZER
COM_
COM1
2/3
ANALYZER
N.C.
R
L
DECODER/
CONTROLLER
2/3
R
L
DECODER/
CONTROLLER
SIGNAL
SIGNAL
GENERATOR 0dBm
NO__
GND
50Ω
GENERATOR 0dBm
COM2
NO2
GND
a) OFF-ISOLATION
b) CROSSTALK
Figure 8. Off-Isolation and Crosstalk
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
© 1999 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
相关型号：
MAX4585
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