19-1496; Rev 0; 6/99
Serially Controlled, Triple 3x2 Audio/Video
Crosspoint Switches
Features
♦ Selectable Soft-Switching Mode for “Clickless”
Audio Operation
♦ 22Ω Typical On-Resistance (+5V Supply)
♦ 5Ω Typical On-Resistance Matching Between
Channels
♦ 2Ω Typical On-Resistance Flatness
♦ Audio Performance
-85dB Off-Isolation at 20kHz
-85dB Crosstalk at 20kHz
0.07% THD with 600Ω Load
♦ Video Performance
-72dB Off-Isolation at 10MHz
-55dB Crosstalk at 10MHz
♦ Serial Interface
2-Wire I2C-Compatible (MAX4548)
3-Wire SPI/QSPI/MICROWIRE-Compatible
(MAX4549)
♦ Single-Supply Operation from +2.7V to +5.5V
Pin Configuration
Applications
Set-Top Boxes
PC Multimedia Boards
Video Conferencing Systems
TOP VIEW
NO1C 1
36 CBIASL
CBIASH 2
35 COM1C
NO2C 3
High-End Audio Systems
33 COM2C
SC 4
Security Systems
NO3C 5
V+ 6
Ordering Information
PART
34 MID5
32 GND
MAX4548
MAX4549
31 COM1A
NO1A 7
30 MID1
N01B 8
29 COM1B
TEMP. RANGE
PIN-PACKAGE
MAX4548EAX
-40°C to +85°C
36 SSOP
SA 9
MAX4549EAX
-40°C to +85°C
36 SSOP
NO2A 10
27 COM2A
N02B 11
26 MID3
28 MID2
SB 12
Functional Diagram appears at end of data sheet.
25 COM2B
N03A 13
24 MID4
N03B 14
23 ABIASH
GND 15
22 ABIASL
GND 16
21 V+
SDA (DIN) 17
SPI and QSPI are trademarks of Motorola, Inc.
MICROWIRE is a trademark of National Semiconductor Corp.
I2C is a trademark of Philips Corp.
20 A0 (CS)
SCL (SCLK) 18
( ) ARE FOR MAX4549
19 A1 (DOUT)
SSOP
________________________________________________________________ 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.
MAX4548/MAX4549
General Description
The MAX4548/MAX4549 serial-interface, programmable,
triple 3x2 audio/video crosspoint switches are ideal for
multimedia applications. The devices include three
crosspoint switch matrices, each containing three inputs
and two outputs. To improve off-isolation, each switch
matrix has a shunt input and each output is selectively
programmable for clickless or regular-mode operation. A
selectable set of internal resistive voltage dividers supplies DC bias for each output when using AC-coupled
inputs. To improve crosstalk, the voltage dividers include
four externally accessible bypass points.
The MAX4548/MAX4549 feature 35Ω max on-resistance, 7Ω on-resistance matching between channels,
5Ω on-resistance flatness, and 0.07% total harmonic
distortion (THD). Additionally, they feature off-isolation
of -85dB at 20kHz and -72dB at 10MHz, with crosstalk
of -85dB at 20kHz and -55dB at 10MHz. The MAX4548
uses a 2-wire I2C™-compatible serial interface, while
the MAX4549 uses a 3-wire SPI™/QSPI™/MICROWIRE™compatible serial interface. These parts are available in
36-pin SSOP packages and are specified for the
extended (-40°C to +85°C) operating range.
MAX4548/MAX4549
Serially Controlled, Triple 3x2 Audio/Video
Crosspoint Switches
ABSOLUTE MAXIMUM RATINGS
V+ to GND ................................................................-0.3V to +6V
NO_ _, S_, MID_, BYP, COM_ _, CBIASL,
ABIASL, CBIASH, ABIASH, DOUT to GND
(Note 1)......................................................-0.3V to (V+ + 0.3V)
CS, A0, A1, SDA, SCL, DIN,
SCLK to GND ........................................................-0.3V to +6V
Continuous Current into Any Terminal..............................±20mA
Peak Current, NO_ _, S_, COM_ _
(pulsed at 1ms, 10% duty cycle max) ...........................±40mA
Continuous Power Dissipation (TA = +70°C)
36-Pin SSOP (derate 11.8mW/°C above +70°C) ..........941mW
Operating Temperature Range ............................-40°C to+85°C
Storage Temperature Range ..............................-65°C to+150°C
Lead Temperature (soldering, 10sec) .............................+300°C
Note 1: Signals on NO_ _, S_, or COM_ _ exceeding V+ or GND are clamped by internal diodes. Limit forward diode current to
maximum rating.
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—Single +5V Supply
(V+ = +5V ±5%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
V+
V
ANALOG SWITCHES
Analog Signal Range (Note 3)
On-Resistance
VNO_ _,
VCOM_ _,
VS_
ICOM_ _ = 4mA,
VNO_ _ or VS_ = 3V,
V+ = 4.75V
TA = +25°C
ICOM_ _ = 4mA,
VNO_ _ or VS_ = 3V,
V+ = 4.75V
TA = +25°C
ICOM_ _ = 4mA;
V+ = 4.75V; VNO_ _
or VS_ = 1V, 2V, 3V
TA = +25°C
VNO_ _ or VS_ = 4.5V,
1V; VCOM_ _ = 1V,
4.5V; V+ = 5.25V
TA = +25°C
-2
TA = TMIN to TMAX
-10
VNO_ _ or VS_= 4.5V, TA = +25°C
ICOM_ _(OFF) 1V; VCOM_ _ = 1V,
TA = TMIN to TMAX
4.5V; V+ = 5.25V
-2
RON
COM_ _ to NO_ _ or S_
On-Resistance Match
Between Channels (Note 4)
∆RON
COM_ _ to NO_ _ or S_
On-Resistance Flatness
(Note 5)
RFLAT
NO_ _ or S_ Off-Leakage
Current (Note 6)
INO_ _(OFF)
COM_ _ Off-Leakage
Current (Note 6)
COM_ _On-Leakage
Current (Note 6)
0
ICOM_ _(ON)
22
TA = TMIN to TMAX
35
Ω
45
5
7
Ω
8
TA = TMIN to TMAX
2
TA = TMIN to TMAX
5
Ω
7
0.04
2
nA
10
0.04
2
nA
-10
10
VNO_ _ or VS_ = 4.5V,
1V, or floating;
VCOM_ _ = 4.5V, 1V;
V+ = 5.25V
TA = +25°C
-2
TA = TMIN to TMAX
-10
fIN = 1kHz, VNO_ _
or VS_ = 1VRMS +
2.5VDC
RL = 600Ω
0.07
RL =10kΩ
0.006
0.04
2
nA
10
AUDIO PERFORMANCE
Total Harmonic Distortion
plus Noise
THD+N
Off-Isolation (Note 7)
VISO(A)
VNO_ _ = 1VRMS, fIN = 20kHz, RL = 600Ω,
S_ = GND, shunt switch on or off
-85
dB
Channel-to-Channel Crosstalk
VCT(A)
VNO_ _ = 1VRMS, fIN = 20kHz,
RL = RS = 600Ω
-85
dB
2
%
_______________________________________________________________________________________
Serially Controlled, Triple 3x2 Audio/Video
Crosspoint Switches
(V+ = +5V ±5%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
VIDEO PERFORMANCE
Off-Isolation (Note 7)
Channel-to-Channel Crosstalk
VISO(V)
VCT(V)
-3dB Bandwidth
BW
Off-Capacitance
COFF(NO)
VNO_ _ or VS_ = 1VRMS,
fIN = 10MHz, RL = 50Ω,
RS =50Ω, S_ = GND
Shunt switch on
-72
Shunt switch off
-62
dB
VNO_ _ or VS_ = 0.5VRMS, RS = 50Ω,
fIN = 10MHz, RL = 50Ω,
-55
dB
RS = 50Ω, RL = 50Ω
250
MHz
f = 1MHz
10
pF
DYNAMIC TIMING WITH CLICKLESS MODE DISABLED (Note 8, Figure 1)
Turn-On Time
tONSD
VNO_ _ or VS_ = 2.5V, TA = +25°C
RL = 5kΩ, CL = 35pF TA = TMIN to TMAX
200
tOFFSD
VNO_ _ or VS_ = 2.5V, TA = +25°C
RL = 300Ω,
TA = TMIN to TMAX
CL = 35pF
100
Turn-Off Time
Break-Before-Make Time
tBBM
ns
200
ns
250
10
VNO_ _ or VS_ = 2.5V
400
500
50
ns
DYNAMIC TIMING WITH CLICKLESS MODE ENABLED (Note 8, Figure 1)
Turn-On Time
tONSE
VNO_ _ or VS_ = 2.5V, RL = 5kΩ, CL = 35pF,
TA = +25°C
12
ms
Turn-Off Time
tOFFSE
VNO_ _ or VS_ = 2.5V, RL = 300Ω, CL = 35pF,
TA = +25°C
3
ms
110
kΩ
BIAS NETWORKS
Bias Network Resistance
RBIAS
POWER SUPPLIES
Supply Voltage Range
V+
Supply Current (Note 9)
I+
2.7
All logic inputs = GND or V+
5.5
V
6
10
µA
TYP
MAX
UNITS
V+
V
ELECTRICAL CHARACTERISTICS—Single +3V Supply
(V+ = +3V ±10%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
ANALOG SWITCHES
Analog Signal Range (Note 3)
On-Resistance
VNO_ _,
VCOM_ _,
VS_
RON
COM_ _ to NO_ _ or S_
On-Resistance Match
Between Channels (Note 4)
∆RON
COM_ _ to NO_ _ or S_
On-Resistance Flatness
(Note 5)
RFLAT
0
ICOM_ _ = 4mA,
VNO_ _ or VS_= 1V,
V+ = 2.7V
TA = +25°C
ICOM_ _ = 4mA,
VNO_ _ or VS_= 1V,
V+ = 2.7V
TA = +25°C
ICOM_ _ = 4mA;
V+ = 2.7V;
VNO_ _ = 1V, 1.5V, 2V
TA = +25°C
40
TA = TMIN to TMAX
Ω
80
5
TA = TMIN to TMAX
TA = TMIN to TMAX
60
7
Ω
8
3
6
Ω
8
_______________________________________________________________________________________
3
MAX4548/MAX4549
ELECTRICAL CHARACTERISTICS—Single +5V Supply (continued)
MAX4548/MAX4549
Serially Controlled, Triple 3x2 Audio/Video
Crosspoint Switches
ELECTRICAL CHARACTERISTICS—Single +3V Supply (continued)
(V+ = +3V ±10%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
VNO_ _ or VS_ = 3V,
0.5V; VCOM_ _ = 0.5V,
3V; V+ = 3.6V
MIN
TYP
MAX
TA = +25°C
-2
0.04
2
TA = TMIN to TMAX
-10
NO_ _ or S_ Off-Leakage
Current (Notes 6, 10)
INO_ _(OFF)
COM _ Off-Leakage
Current (Notes 6, 10)
VNO_ _ or VS_ = 3V,
ICOM_ _(OFF) 0.5V; VCOM_ _ = 0.5V,
3V; V+ = 3.6V
TA = +25°C
-2
TA = TMIN to TMAX
-10
COM _ On-Leakage
Current (Notes 6, 10)
VNO_ _ or VS_ = 0.5V,
3V, or floating;
ICOM_ _(ON)
VCOM_ _ = 0.5V, 3V;
V+ = 3.6V
TA = +25°C
-2
TA = TMIN to TMAX
-10
UNITS
nA
10
0.04
2
nA
10
0.04
2
nA
10
AUDIO PERFORMANCE
fIN = 1kHz, VNO_ _
or VS_ = 1.5VDC +
0.5VRMS
RL = 600Ω
0.1
RL = 10Ω
0.01
Total Harmonic Distortion
plus Noise
THD+N
Off-Isolation (Note 7)
VISO(A)
VNO_ _ = 0.5VRMS, fIN = 20kHz,
RL = 600Ω, S– = GND,
shunt switch on or off
-85
dB
Channel-to-Channel Crosstalk
VCT(A)
VNO_ _ = 0.5VRMS, fIN = 20kHz,
RL = 600kΩ, RS = 600Ω
-85
dB
VISO(V)
VNO_ _ or VS _ =
0.5VRMS,
fIN = 10MHz,
RL = 50Ω, RS = 50Ω
%
VIDEO PERFORMANCE
Off-Isolation (Note 7)
Channel-to-Channel Crosstalk
VCT(V)
-3dB Bandwidth
BW
Off-Capacitance
COFF(NO)
Shunt switch on
-72
Shunt switch off
-62
dB
VNO_ _ or VS_ = 0.5VRMS,
RS = 50Ω, fIN = 10MHz, RL = 50Ω
-55
dB
RS = 50Ω, RL = 50Ω
200
MHz
f = 1MHz
10
pF
DYNAMIC TIMING WITH CLICKLESS MODE DISABLED (Notes 8 and 12, Figure 1)
Turn-On Time
Turn-Off Time
Break-Before-Make Time
tONSD
tOFFSD
tBBM
VNO_ _ or VS_ = 1.5V,
RL = 5kΩ, CL = 35pF
400
TA = +25°C
800
ns
1000
TA = TMIN to TMAX
200
TA = +25°C
VNO_ _ or VS_ = 1.5V,
RL = 300Ω, CL = 35pF T = T
A
MIN to TMAX
VNO_ _ or VS_ = 1.5V
350
ns
500
10
100
ns
DYNAMIC TIMING WITH CLICKLESS MODE ENABLED (Notes 8 and 12, Figure 1)
Turn-On Time
tONSE
VNO_ _ or VS_ = 1.5V, RL = 5kΩ, CL = 35pF
12
ms
Turn-Off Time
tOFFSE
VNO_ _ or VS_ = 1.5V, RL = 300Ω, CL = 35pF
3
ms
110
kΩ
BIAS NETWORK
Bias Network Resistance
4
RBIAS
_______________________________________________________________________________________
Serially Controlled, Triple 3x2 Audio/Video
Crosspoint Switches
(V+ = +2.7V to +5.25V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
DIGITAL INPUTS (SCLK, DIN, CS, SCL, SDA, A0, A1)
V+ = 5V
Input Low Voltage
VIL
V+ = 3V
Input High Voltage
VIH
Input Hysteresis
VHYST
Input Leakage Current
ILEAK
Input Capacitance
MAX
0.8
0.6
V+ = 5V
3
V+ = 3V
2
Digital inputs = GND or V+
-1
f = 1MHz
Output Low Voltage
VOL
ISINK = 6mA
DOUT Output High Voltage
VOH
ISOURCE = 0.5mA
V
V
0.2
CIN
UNITS
0.001
V
1
5
µA
pF
DIGITAL OUTPUTS (DOUT, SDA)
0.4
V+ - 0.5
V
V
2-WIRE TIMING CHARACTERISTICS (Figure 3)
(V+ = +2.7V to +5.25V, fSCL = 100kHz, TA = TMIN to TMAX, unless otherwise noted.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
V+ = 4.75V to 5.25V
0
400
V+ = 2.7V to 5.25V
0
100
UNITS
SCL Clock Frequency
fSCL
Bus-Free Time between Stop
and Start Condition
tBUF
4.7
µs
tHD:STA
4
µs
Hold Time After Start Condition
Pulse Width of Suppressed
Spike (Note 3)
0
STOP Condition Setup Time
tSU:STO
Data Hold Time
Data Setup Time
50
kHz
ns
4
µs
tHD:DAT
0
µs
tSU:DAT
250
ns
Clock Low Period
tLOW
4.7
µs
Clock High Period
tHIGH
4
µs
SCL/SDA Rise Time (Note 11)
tR
20 +
0.1Cb
300
ns
SCL/SDA Fall Time (Note 11)
tF
20 +
0.01Cb
300
ns
_______________________________________________________________________________________
5
MAX4548/MAX4549
I/O INTERFACE CHARACTERISTICS
3-WIRE TIMING CHARACTERISTICS (Figure 5)
(V+ = +2.7V to +5.25V, TA = TMIN to TMAX, unless otherwise noted.)
PARAMETER
SYMBOL
CONDITIONS
MIN
DIN to SCLK Setup
tDS
0
0
100
DIN to SCLK Hold
tDH
0
SCLK Fall to Output Data Valid
tDO
CS to SCLK Rise Setup
tCSS
Operating Frequency
V+ = 4.75V to 5.25V
V+ = 2.7V to 5.25V
fOP
TYP
MAX
UNITS
10
2.1
MHz
ns
ns
CLOAD = 50pF
200
ns
100
ns
CS to SCLK Rise Hold
tCSH
0
ns
CS Pulse Width High
tCSW
40
ns
SCLK Pulse Width High
tCH
200
ns
SCLK Pulse Width Low
tCL
200
Rise Time (SCLK, DIN, CS)
tR
2
µs
Fall Time (SCLK, DIN, CS)
tF
2
µs
ns
The algebraic convention is used in this data sheet; the most negative value is shown in the minimum column.
Guaranteed by design. Not subject to production testing.
∆RON = RON(MAX) - RON(MIN).
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 100% tested at maximum rated temperature and guaranteed by correlation at TA = +25°C.
Note 7: Off-isolation = 20log (VCOM_ / VNO_ _ ), VCOM_ = output, VNO_ _ = input to off switch.
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 20% V+ and 70% V+, unless otherwise noted.
Note 9: Supply current can be as high as 2mA per switch during switch transitions in the clickless mode, corresponding to a 48mA
total supply transient current requirement.
Note 10: Leakage testing is guaranteed by testing with a +5.25V supply.
Note 11: Cb = capacitance of one bus line in pF. Tested with Cb = 400pF.
Note 12: Typical values are for MAX4548 devices.
Note 2:
Note 3:
Note 4:
Note 5:
Typical Operating Characteristics
(V+ = +5V, TA = +25°C, unless otherwise noted.)
ON-RESISTANCE
vs. VCOM AND TEMPERATURE
26
V+ = 2.7V
V+ = 3.3V
25
RDS (ON) (Ω)
30
TA = +85°C
24
TA = +70°C
22
20
TA = +25°C
18
1000
100
COM_ON
10
COM_OFF
1
20
V+ = 5.0V
16
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
VCOM (V)
NO_OFF
TA = -40°C
0.1
14
15
6
10,000
MAX4548 toc03
35
LEAKAGE CURRENT vs. TEMPERATURE
MAX4548 toc02
28
MAX4548 toc01
40
LEAKAGE CURRRENT (pA)
ON-RESISTANCE vs. VCOM
RDS (ON) (Ω)
MAX4548/MAX4549
Serially Controlled, Triple 3x2 Audio/Video
Crosspoint Switches
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
VCOM (V)
-40
-20
0
20
40
TEMPERATURE (°C)
_______________________________________________________________________________________
60
80
Serially Controlled, Triple 3x2 Audio/Video
Crosspoint Switches
2
MAX4548 toc06
V+ = 5V
6.2
1
MAX4548 toc05
6.4
600Ω IN AND OUT
SIGNAL = 1VRMS
V+ = 3.3V
Q (pC)
5.8
THD+N (%)
1
6.0
0
5.6
0.1
-1
5.4
5.2
-2
5.0
-3
-40
-20
0
20
40
60
0
80
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
ALL-HOSTILE CROSSTALK
600Ω IN AND OUT
-20
LOSS (dB)
LOSS (dB)
100,000
-40
CROSSTALK
-50
OFF-ISOLATION
(WITH SHUNT)
-70
10,000
AUDIO FREQUENCY CHARACTERISTICS
-30
-60
1000
0
MAX4548 toc07
-10
100
FREQUENCY (Hz)
VIDEO FREQUENCY CHARACTERISTICS
0
-40
10
VCOM
TEMPERATURE (°C)
-20
0.01
MAX4548 toc08
4.8
-60
OFF-ISOLATION
-80
CROSSTALK
-80
OFF-ISOLATION
(WITHOUT SHUNT)
-90
-100
-100
0.5
1
10
-120
100
10
FREQUENCY (MHz)
100
1k
10k
100k
FREQUENCY (Hz)
AUDIO FREQUENCY RESPONSE
VIDEO FREQUENCY RESPONSE
2
MAX4548toc10
0
MAX4548 toc09
0
-0.01
-0.02
-0.03
LOSS (dB)
4
LOSS (dB)
SUPPLY CURRENT (µA)
3
MAX4548 toc04
6.8
.
6.6
TOTAL HARMONIC
DISTORTION PLUS NOISE vs. FREQUENCY
CHARGE INJECTION vs. VCOM
SUPPLY CURRENT vs. TEMPERATURE
6
8
-0.04
-0.05
-0.06
-0.07
-0.08
10
RIN = ROUT = 50Ω
-0.09
50Ω IN AND OUT
-0.10
12
0.1
1
10
FREQUENCY (MHz)
100
1000
10
100
1k
10k
100k
FREQUENCY (Hz)
_______________________________________________________________________________________
7
MAX4548/MAX4549
Typical Operating Characteristics (continued)
(V+ = +5V, TA = +25°C, unless otherwise noted.)
Typical Operating Characteristics (continued)
(V+ = +5V, TA = +25°C, unless otherwise noted.)
ON/OFF TIME vs. TEMPERATURE
(HARD MODE)
MAX4548 toc11
TURN-ON TIME, V+ = 3V
250
MAX4548toc12
COM RISE TIME (SOFT MODE)
300
200
TIME (ns)
TURN-ON TIME, V+ = 5V
VCOM
(1V/div)
150
TURN-OFF TIME, V+ = 3V
100
50
TURN-OFF TIME, V+ = 5V
0
0
-40
-20
0
20
40
60
80
100µs/div
TEMPERATURE (°C)
COM FALL TIME (SOFT MODE)
MAX4548toc14
MAX4548toc13
COM TURN-ON TIME (HARD MODE)
VCS
(5V/div)
0
VCOM
(1V/div)
VCOM
(2V/div)
0
0
50ns/div
COM TURN-OFF TIME (HARD MODE)
COM ON/OFF TIMES (SOFT MODE)
VCS
(5V/div)
0
MAX4548 toc16
100µs/div
MAX4548toc15
MAX4548/MAX4549
Serially Controlled, Triple 3x2 Audio/Video
Crosspoint Switches
VCS
(5V/div)
0
TURN-OFF TIME
VCOM
(2V/div)
0
VCOM
(2V/div)
0
VCOM
(2V/div)
TURN-ON TIME
0
25ns/div
8
0
2
3
6
8
10 12 14 16 18 20
TIME (ms)
_______________________________________________________________________________________
Serially Controlled, Triple 3x2 Audio/Video
Crosspoint Switches
PIN
NAME
FUNCTION
MAX4548
MAX4549
1
1
NO1C
2
2
CBIASH
3
3
NO2C
4
4
SC
5
5
NO3C
6, 21
6, 21
V+
7
7
NO1A
Input 1 to Crosspoint A
8
8
NO1B
Input 1 to Crosspoint B
9
9
SA
10
10
NO2A
Input 2 to Crosspoint A
11
11
NO2B
Input 2 to Crosspoint B
12
12
SB
13
13
NO3A
Input 3 to Crosspoint A
14
14
NO3B
Input 3 to Crosspoint B
15, 16, 32
15, 16, 32
GND
Ground
17
–
SDA
2-Wire Serial-Interface Data Input. Data is clocked in on SCL’s rising edge.
–
17
DIN
3-Wire Serial-Interface Data Input. Data is clocked in on SCLK’s rising edge.
18
–
SCL
2-Wire Serial-Interface Clock Input
–
18
SCLK
3-Wire Serial-Interface Clock Input
19
–
A1
–
19
DOUT
20
–
A0
LSB of 2-Wire Serial-Interface Address Field
–
20
CS
Chip Select of 3-Wire Serial Interface. Logic low on CS enables serial data to be clocked
in to device. Programming commands are executed on CS’s rising edge.
22
22
ABIASL
Low Side of Bias Network for Crosspoint A and B. Use to give the A and B outputs a DC
bias when inputs are AC-coupled (refer to the Using the Internal Bias Resistors section).
23
23
ABIASH
High Side of Bias Network for Crosspoint A and B. Use to give the A and B outputs a DC
bias when inputs are AC-coupled (refer to the Using the Internal Bias Resistors section).
24
24
MID4
25
25
COM2B
Input 1 to Crosspoint C
High Side of Bias Network for Crosspoint C. Use to give the C outputs a DC bias when
inputs are AC-coupled (refer to the Using the Internal Bias Resistors section).
Input 2 to Crosspoint C
Shunt Input to Crosspoint C. Use for shunt capacitor of AC ground connection to improve
off-isolation, or as an additional input to switch matrix C.
Input 3 to Crosspoint C
Positive Supply Voltage. Supply range is 2.7V to 5.5V.
Shunt Input to Crosspoint A. Use for shunt capacitor of AC ground connection to improve
off-isolation, or as an additional input to switch matrix A.
Shunt Input to Crosspoint B. Use for shunt capacitor of AC ground connection to improve
off-isolation, or as an additional input to switch matrix B.
LSB+1 of 2-Wire Serial-Interface Address Field
Data Output of 3-Wire Serial-Interface. Input data is clocked on SCLK’s falling edge
delayed by 24 clock cycles. DOUT remains active when CS is high.
Audio Bypass for SA and SB Inputs
Output 2 of Crosspoint B
_______________________________________________________________________________________
9
MAX4548/MAX4549
Pin Description
MAX4548/MAX4549
Serially Controlled, Triple 3x2 Audio/Video
Crosspoint Switches
Pin Description (continued)
PIN
NAME
FUNCTION
MAX4548
MAX4549
26
26
MID3
27
27
COM2A
28
28
MID2
29
29
COM1B
30
30
MID1
31
31
COM1A
Output 1 of Crosspoint A
33
33
COM2C
Output 2 of Crosspoint C
34
34
MID5
35
35
COM1C
Output 1 of Crosspoint C
36
36
CBIASL
High Side of Bias Network for Crosspoint C. Use to give the C outputs a DC bias when
inputs are AC-coupled (refer to the Using the Internal Bias Resistors section).
Audio Bypass for IN3A and IN3B Inputs
Output 2 of Crosspoint A
Audio Bypass for IN2A and IN2B Inputs
Output 1 of Crosspoint B
Audio Bypass for IN1A and IN1B Inputs
Video Bypass for All Inputs to Crosspoint C
ACKNOWLEDGE
BIT
3V
MAX4548
MAX4549
0
V+
VOUT
10nF
2-WIRE
0
V+
VNO_ _
tR > 20ns
tF > 20ns
50%
SCL
NO_ _
VOUT
COM _
VOUT
RL
300Ω
2 OR 3
0
VOUT - 0.5V
tOFF
CL
35pF
3V
DECODER/
CONTROLLER
µP
+0.5V
tON
CS
50%
0
SERIAL
INTERFACE
VOUT
0.9 • VOUT
GND
3-WIRE
0
tON
CL INCLUDES FIXTURE AND STRAY CAPACITANCE.
VOUT = VCOM [RL / (RL + RON)]
VOUT
0
0.1 • VOUT
tOFF
Figure 1. Switching Times
10
______________________________________________________________________________________
?W2@@@@@@@@@h?W2@@@@@@@@@
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W&@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@he?W&@@@@@@@@@@@@@@@@@@@hf?@@@@@@@@@@@@Lhf@@@@@@@@he?W&@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@?
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?
Serially Controlled, Triple 3x2 Audio/Video
Crosspoint Switches
RS
SIGNAL
GENERATOR
NO1_
2/3
VOUT
RL
10k
COM1_
ANALYZER
COM2_
ANALYZER
10k
RL
DECODER/
ENCODER
V+/2
V+
S_
GND
10nF
1µF
10k
VIN
Figure 2a. Off-Isolation
RS
VIN
RS
10k
SIGNAL
GENERATOR
10k
VOUT
10k
SIGNAL
GENERATOR
MAX4548
MAX4549
Figure 2c. All-Hostile Crosstalk
Detailed Description
10k
Figure 2b. Crosstalk
MAX4548
MAX4549
10k
The MAX4548/MAX4549 are serial-interface, programmable, triple 3x2 audio/video crosspoint switches. Each
device contains two crosspoint switches with a common bypass network and another crosspoint switch
with its own bypass network. The switches are independently controlled through the on-chip serial interface.
The MAX4548 uses a 2-wire I2C-compatible serial communications protocol, while the MAX4549 uses a 3-wire
SPI/QSPI/MICROWIRE-compatible serial communications protocol.
These ICs include twelve selectable bias-resistor networks (one for each input) for use with AC-coupled
input signals. They operate from a single supply of
+2.7V to +5.5V and are optimized for use in the audio
frequency range to 20kHz and at video frequencies to
10MHz. They feature 35Ω max on-resistance, 7Ω onresistance matching between channels, 5Ω on-resistance flatness, and as low as 0.07% total harmonic
distortion.
______________________________________________________________________________________
11
MAX4548/MAX4549
V+/2
MAX4548
MAX4549
MAX4548/MAX4549
Serially Controlled, Triple 3x2 Audio/Video
Crosspoint Switches
Table 2. COM Data-Byte Format
(C0, C1, C2, C3, C4, C5 = “1”)
Table 1. Command-Byte Format
BIT
REGISTER
C7
Clickless Mode
C6
Bias
C5
COM2C
C4
COM1C
D7
Don’t care
—
C3
COM2B
D6
Don’t care
—
C2
COM1B
D5
Don’t care
—
C1
COM2A
D4
Don’t care
—
C0
COM1A
D3
Controls the switch connected to S_;
1 = close switch, 0 = open switch.
1
D2
Controls the switch connected to NO3_;
1 = close switch, 0 = open switch.
0
D1
Controls the switch connected to NO2_;
1 = close switch, 0 = open switch.
0
D0
Controls the switch connected to NO1_;
1 = close switch, 0 = open switch.
0
BIT
Audio off-isolation is -85dB at 20kHz, crosstalk is
-85dB at 20kHz, and video off-isolation is -62dB at
10MHz. The SA, SB, and SC (shunt) inputs further
improve off-isolation, allowing for the addition of external shunt capacitors to connect the outputs to AC
grounds. When using the bias resistors, MID_ inputs
improve crosstalk by providing an AC ground at the
common bias points. Resistance from the bias points to
the inputs allows AC signals to pass through the device
and improve crosstalk performance (refer to the
Functional Diagram). These devices feature a clickless
operation mode for noiseless audio switching. Use the
serial interface to select the clickless or standardswitching mode for each individual output.
POWER-UP
DEFAULT
STATE
DESCRIPTION
Applications Information
The MAX4548/MAX4549 are divided into five functional
blocks: the control-logic block, three switch-matrix
blocks, and the bias-resistor block (see Functional
Diagram). The control-logic block accepts commands
through the serial interface and uses those commands
to control the four remaining blocks.
SCL
SDA
A0
A7
SRT
C7
D7
C0
ACK
D0
ACK
ACK
STOP
Figure 3. 2-Wire Serial-Interface Timing Diagram (“WriteByte’’)
SCL
SDA
A7
SRT
A0
C7
ACK
D15
C0
ACK
D8
D7
ACK
D0
ACK
Figure 4. 2-Wire Serial-Interface Timing Diagram (“WriteWord’’)
12
______________________________________________________________________________________
STOP
Serially Controlled, Triple 3x2 Audio/Video
Crosspoint Switches
The devices are programmed with a command byte and
a data byte or data word (2 bytes). Each bit of the
command byte selects one of the functional blocks to be
controlled by the subsequent data byte (word). The data
byte (word) sets the state of the selected block(s). For
the three switch-matrix blocks, the data byte sets the
switch state. For the bias-resistor block, the data word
A
tLOW
B
tHIGH
C
controls which bias network is active (see Functional
Diagram).
A logic “1” in any bit position of the data byte makes
that function active, while a logic “0” makes it inactive.
Tables 1–4 describe the command byte and the corresponding data byte. If more than one bit of the command byte is set, the data byte programs all of the
corresponding blocks. This operation is useful, for
instance, to simultaneously set all switch matrices to
E
D
F
G
H
I
J
SCL
SDA
tSU:STA tHD:STA
tSU:DAT
tHD:DAT
A = START CONDITION
B = MSB OF ADDRESS BYTE
C = LSB OF ADDRESS BYTE
D = ACKNOWLEDGE CLOCKED INTO MASTER
E = MSB OF COMMAND BYTE
tSU:STO tBUF
F = LSB OF COMMAND BYTE
G = ACKNOWLEDGE CLOCKED INTO MASTER
H = MSB OF DATA BYTE/WORD
I = LSB OF DATA BYTE/WORD
J = ACKNOWLEDGE CLOCKED INTO MASTER
Figure 5. 2-Wire Serial-Interface Timing Details
Table 3. Bias Data-Byte (C6 = “1”)
BIT
DESCRIPTION
POWER-UP
DEFAULT
STATE
D15
Don’t care
–
D14
Don’t care
–
D13
Don’t care
–
D12
Don’t care
–
D11
Controls SC bias resistors; 1 = connect bias resistors, 0 = disconnect bias resistors.
1
D10
Controls NO3C bias resistors; 1 = connect bias resistors, 0 = disconnect bias resistors.
1
D9
Controls NO2C bias resistors; 1 = connect bias resistors, 0 = disconnect bias resistors.
1
D8
Controls NO1C bias resistors; 1 = connect bias resistors, 0 = disconnect bias resistors.
1
D7
Controls SB bias resistors; 1 = connect bias resistors, 0 = disconnect bias resistors.
1
D6
Controls SA bias resistors; 1 = connect bias resistors, 0 = disconnect bias resistors.
1
D5
Controls NO3B bias resistors; 1 = connect bias resistors, 0 = disconnect bias resistors.
1
D4
Controls NO3A bias resistors; 1 = connect bias resistors, 0 = disconnect bias resistors.
1
D3
Controls NO2B bias resistors; 1 = connect bias resistors, 0 = disconnect bias resistors.
1
D2
Controls NO2A bias resistors; 1 = connect bias resistors, 0 = disconnect bias resistors.
1
D1
Controls NO1B bias resistors; 1 = connect bias resistors, 0 = disconnect bias resistors.
1
D0
Controls NO1A bias resistors; 1 = connect bias resistors, 0 = disconnect bias resistors.
1
______________________________________________________________________________________
13
MAX4548/MAX4549
Command-Byte and Data-Byte
Programming
MAX4548/MAX4549
Serially Controlled, Triple 3x2 Audio/Video
Crosspoint Switches
Table 4. Clickless Mode Format (C7 = “1”)
BIT
POWER-UP
DEFAULT
STATE
DESCRIPTION
D7
Don’t care
—
D6
Don’t care
—
D5
Controls COM2C clickless mode; 1 = enables clickless mode, 0 = disables clickless mode.
1
D4
Controls COM1C clickless mode; 1 = enables clickless mode, 0 = disables clickless mode.
1
D3
Controls COM2B clickless mode; 1 = enables clickless mode, 0 = disables clickless mode.
1
D2
Controls COM1B clickless mode; 1 = enables clickless mode, 0 = disables clickless mode.
1
D1
Controls COM2A clickless mode; 1 = enables clickless mode, 0 = disables clickless mode.
1
D0
Controls COM1A clickless mode; 1 = enables clickless mode, 0 = disables clickless mode.
1
Table 5. “WriteByte” Protocol
ADDRESS BYTE
COMMAND BYTE
DATA BYTE
A7 A6 A5 A4 A3 A2 A1 A0
C7 C6 C5 C4 C3 C2 C1 C0
D7 D6 D5 D4 D3 D2 D1 D0
S
R
T
1
0
0
1
1
A1 A0
0
A
C
K
C
L
I
C
K
B
I
A
S
C
O
M
2
C
C
O
M
1
C
C
O
M
2
B
C
O
M
1
B
C
O
M
2
A
C
O
M
1
A
A
C
K
A
C
K
S
T
O
P
SRT = Start Condition
ACK = Acknowledge Condition
STOP = Stop Condition
Table 6. “WriteWord” Protocol
S
R
T
ADDRESS BYTE
COMMAND BYTE
A7 A6 A5 A4 A3 A2 A1 A0
C7 C6 C5 C4 C3 C2 C1 C0
1
0
0
1
1
A1 A0
0
A
C
K
C
L
I
C
K
B
I
A
S
C
O
M
2
C
C
O
M
1
C
C
O
M
2
B
C
O
M
1
B
DATA WORD
C
O
M
2
A
C
O
M
1
A
D15 D14 D13 D12 D11 D10 D9 D8
A
C
K
D7 D6 D5 D4 D3 D2 D1 D0
A
C
K
SRT = Start Condition
ACK = Acknowledge Condition
STOP = Stop Condition
Table 7. “SPI” Protocol
COMMAND BYTE
DATA WORD
C7 C6 C5 C4 C3 C2 C1 C0 D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
C
L
I
C
K
B
I
A
S
C
O
M
2
C
C
O
M
1
C
C
O
M
2
B
C
O
M
1
B
C
O
M
2
A
C
O
M
1
A
SRT = Start Condition
ACK = Acknowledge Condition
STOP = Stop Condition
14
______________________________________________________________________________________
A
C
K
S
T
O
P
Serially Controlled, Triple 3x2 Audio/Video
Crosspoint Switches
MAX4548/MAX4549
CS
SCLK
1
DIN
24
C7
D0
C0 D15
COMMAND BYTE
DATA BYTE
Figure 6. 3-Wire Serial-Interface Communication
•••
CS
tCSH
tCSS
tCL
tCH
SCLK
tCSH
•••
tDS
tDH
•••
DIN
tDV
tDO
tTR
•••
DOUT
Figure 7. 3-Wire Serial-Interface Timing Details
the same configuration. Any block that is not selected
in the command byte remains unchanged.
2-Wire Serial Interface
The MAX4548 uses a 2-wire I2C-compatible serial interface. The COM_ _ registers and the Clickless Mode
register use the “WriteByte” protocol, which consists of
an address byte, followed by a command byte, followed by a data byte (Table 5). The Bias register uses
the “WriteWord” protocol, which consists of an address
byte, followed by a command byte, followed by a data
word (Table 6).
To address a given chip, the A0 and A1 bits in the
address byte must duplicate the values present at the
A0 and A1 pins of that chip. The rest of the address bits
must match those shown in Tables 5 and 6. The command and data-byte details are described in the
Command-Byte and Data-Byte Programming section.
The 2-wire serial interface requires only two I/O lines of
a standard microprocessor port. Figures 3, 4, and 5
detail the timing diagram for signals on the 2-wire bus,
while Tables 5 and 6 detail the format of the signals.
The MAX4548 is a receive-only device and must be
controlled 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, a command byte, a data byte or word,
and finally a stop condition. The slave device acknowledges the recognition of its address by pulling the SDA
line low for one clock period after the address byte is
transmitted. The slave device also issues a similar
acknowledgment after the command byte and again
after each data byte.
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 master has finished
communicating with the slave, it issues a stop condition
by transitioning SDA from low to high while SCL is high.
The bus is then free for another transmission.
______________________________________________________________________________________
15
MAX4548/MAX4549
Serially Controlled, Triple 3x2 Audio/Video
Crosspoint Switches
Slave Address (Address Byte)
The MAX4548 uses an 8-bit slave address. To select a
slave address, connect A0 and A1 to V+ or GND. The
MAX4548 has four possible slave addresses, thus a
maximum of four of these devices may share the same
2-bit address bus. The slave devices on the MAX4548
monitor the serial bus continuously, waiting for a start
condition followed by an address byte. When a slave
device recognizes its address, it acknowledges that it is
ready for further communication by pulling the SDA line
low for one clock period.
3-Wire Serial Interface
The MAX4549 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 24 bits is needed in
each write cycle. Segmented write cycles are allowed
(three 8-bit-wide transfers) if CS remains low. The first
bit clock into the MAX4549 is the command byte’s MSB,
and the last bit clocked in is the data byte’s LSB. When
programming the COM_ _ registers and the Clickless
Mode register, the last eight bits of the data word are
“don’t care.” While shifting data, the device remains in
its original configuration. After all 24 bits are clocked
into the input shift register, a rising edge on CS latches
the data into the MAX4549 internal registers, initiating
the device’s change of state. Figures 6 and 7 and Table
7 show the details of the 3-wire protocol, as it applies to
the MAX4549.
DOUT is the shift register’s output. Data at DOUT is simply the input data delayed by 24 clock cycles, with data
appearing synchronous with SCLK’s falling edge.
Transitions at DIN and SCLK have no effect when CS is
high, and DOUT holds the last bit in the shift register.
Daisy-Chaining
To program several MAX4549s, “daisy-chain” the devices
by connecting DOUT of the first device to DIN of the second, and so on. The CS pins of all devices are connected
together, and data is shifted through the MAX4549 in
series. Twenty-four bits of data per device are required
for proper programming of all devices. When CS is
brought high, all devices are updated simultaneously.
Addressable Serial Interface
To program several MAX4549s individually using a single processor, connect the DIN pins of each MAX4549
together and control CS on each MAX4549 separately.
To select a particular device, drive the corresponding
CS low, clock in the 24-bit command, then drive CS high
to execute the command. Typically only one MAX4549
is addressed at a time.
16
Improving Off-Isolation
To improve off-isolation, connect the S_ input to ground
either directly (DC ground) or through capacitors (AC
ground). Closing S_ then effectively grounds the unused
outputs.
Using the Internal Bias Resistors
Use the internal bias-resistor networks to give the
switch outputs a DC bias when the switch terminals are
AC-coupled. Programming the switches that connect
the bias resistors to the inputs is accomplished via bit
C6 of the command byte. Connect _BIASH and _BIASL
inputs to DC levels (for example, V+ and GND), and
activate the switch connecting the appropriate outputs.
This applies a voltage midway between _BIASH and
_BIASL to the input (refer to Tables 1 and 4, and the
Functional Diagram). To improve crosstalk when using
the bias resistors, connect the MID_ inputs to ground
through capacitors.
Clickless Switching
Audible switching transients (“clicks”) are eliminated in
this mode of operation. When an output is configured as
“clickless,” the gate signal of the switches connected to
the output are controlled with slow-moving voltages. As
a result, the output slew rates are significantly reduced.
Program clickless operation via bit C7 of the command
byte (refer to Tables 1 and 4, and the Functional
Diagram). Each operating switch may draw 2mA during
a transition. When another command is given while a
switch is changing state in the soft mode, the
MAX4548/MAX4549 will complete the previous command in the hard mode. To avoid this situation, do not
issue a second command until the transition of the
switch is complete.
Power-Up State
The MAX4548/MAX4549 feature a preset power-up state.
Refer to Tables 2, 3, and 4 to determine the power-up
state of the devices.
Bypass Capacitors
The MAX4548/MAX4549 have five bypass pins for the
internal bias resistor networks (MID_). The equivalent AC
impedance at these pins is 10kΩ. To improve crosstalk
performance, bypass MID_ pins with 10µF. For lowest
cost, standard aluminum electrolytic capacitors in parallel
with 0.1µF ceramic chip capacitors perform well in audio
applications. For computer audio applications, a single
1µF capacitor is sufficient. For telecom voice applications, a 0.1µF capacitor is adequate. For video applications, bypass MID_ with 0.1µF in parallel with 1000pF.
This provides a low impedance across the entire video
bandwidth.
______________________________________________________________________________________
Serially Controlled, Triple 3x2 Audio/Video
Crosspoint Switches
31
COM1A
27
COM2A
29
COM1B
25
COM2B
35
COM1C
33
COM2C
19
A1 (DOUT)
20
A0 (CS)
18
SCL (SCLK)
17
SDA (DIN)
23
22
ABIASL
2
36
CBIASL
NO1A
7
NO2A
10
NO3A
13
SA
9
MAX4548
MAX4549
SWITCH MATRIX A
NO1B
8
NO2B
11
NO3B
14
SB
12
SWITCH MATRIX B
NO1C
1
NO2C
3
NO3C
5
SC
4
SWITCH MATRIX C
V+
GND
ABIASH
CBIASH
CONTROL LOGIC
6, 21
15, 16, 32
BIAS RESISTOR NETWORK
MID1
MID2
MID3
30
34
28
26
24
MID5
MID4
( ) ARE FOR MAX4549
______________________________________________________________________________________
17
MAX4548/MAX4549
Functional Diagram
________________________________________________________Package Information
SSOP.EPS
MAX4548/MAX4549
Serially Controlled, Triple 3x2 Audio/Video
Crosspoint Switches
Chip Information
TRANSISTOR COUNT: 7700
SUBSTRATE IS INTERNALLY CONNECTED TO V+.
18
______________________________________________________________________________________
Serially Controlled, Triple 3x2 Audio/Video
Crosspoint Switches
MAX4548/MAX4549
NOTES
______________________________________________________________________________________
19
MAX4548/MAX4549
Serially Controlled, Triple 3x2 Audio/Video
Crosspoint Switches
NOTES
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.
20 ____________________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.
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