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19-1496; Rev 0; 6/99
Serially Controlled, Triple 3x2 Audio/Video Crosspoint Switches
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 35 max on-resistance, 7 on-resistance matching between channels, 5 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 I2CTM-compatible serial interface, while the MAX4549 uses a 3-wire SPITM/QSPITM/MICROWIRETMcompatible serial interface. These parts are available in 36-pin SSOP packages and are specified for the extended (-40C to +85C) operating range.
Features
o Selectable Soft-Switching Mode for "Clickless" Audio Operation o 22 Typical On-Resistance (+5V Supply) o 5 Typical On-Resistance Matching Between Channels o 2 Typical On-Resistance Flatness o Audio Performance -85dB Off-Isolation at 20kHz -85dB Crosstalk at 20kHz 0.07% THD with 600 Load o Video Performance -72dB Off-Isolation at 10MHz -55dB Crosstalk at 10MHz o Serial Interface 2-Wire I2C-Compatible (MAX4548) 3-Wire SPI/QSPI/MICROWIRE-Compatible (MAX4549) o Single-Supply Operation from +2.7V to +5.5V
MAX4548/MAX4549
Pin Configuration Applications
Set-Top Boxes PC Multimedia Boards Video Conferencing Systems High-End Audio Systems Security Systems
TOP VIEW
NO1C 1 CBIASH 2 NO2C 3 SC 4 NO3C 5 V+ 6 36 CBIASL 35 COM1C 34 MID5 33 COM2C 32 GND
Ordering Information
PART MAX4548EAX MAX4549EAX TEMP. RANGE -40C to +85C -40C to +85C PIN-PACKAGE 36 SSOP 36 SSOP
MAX4548 MAX4549
31 COM1A 30 MID1 29 COM1B 28 MID2 27 COM2A 26 MID3 25 COM2B 24 MID4 23 ABIASH 22 ABIASL 21 V+ 20 A0 (CS) 19 A1 (DOUT)
NO1A 7 N01B 8 SA 9 NO2A 10 N02B 11 SB 12 N03A 13
Functional Diagram appears at end of data sheet.
N03B 14 GND 15 GND 16 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.
SCL (SCLK) 18 ( ) ARE FOR MAX4549
SSOP 1
________________________________________________________________ Maxim Integrated Products
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Serially Controlled, Triple 3x2 Audio/Video Crosspoint Switches MAX4548/MAX4549
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 = +70C) 36-Pin SSOP (derate 11.8mW/C above +70C) ..........941mW Operating Temperature Range ............................-40C to+85C Storage Temperature Range ..............................-65C to+150C Lead Temperature (soldering, 10sec) .............................+300C
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 = +25C.) (Note 2) PARAMETER ANALOG SWITCHES Analog Signal Range (Note 3) VNO_ _, VCOM_ _, VS_ RON ICOM_ _ = 4mA, VNO_ _ or VS_ = 3V, V+ = 4.75V ICOM_ _ = 4mA, VNO_ _ or VS_ = 3V, V+ = 4.75V ICOM_ _ = 4mA; V+ = 4.75V; VNO_ _ or VS_ = 1V, 2V, 3V VNO_ _ or VS_ = 4.5V, 1V; VCOM_ _ = 1V, 4.5V; V+ = 5.25V TA = +25C TA = TMIN to TMAX TA = +25C TA = TMIN to TMAX TA = +25C TA = TMIN to TMAX TA = +25C TA = TMIN to TMAX -2 -10 -2 -10 -2 -10 0.04 0.04 0.04 2 5 0 22 V+ 35 45 7 8 5 7 2 nA 10 2 nA 10 2 nA TA = TMIN to TMAX 10 V SYMBOL CONDITIONS MIN TYP MAX UNITS
On-Resistance COM_ _ to NO_ _ or S_ On-Resistance Match Between Channels (Note 4) COM_ _ to NO_ _ or S_ On-Resistance Flatness (Note 5) NO_ _ or S_ Off-Leakage Current (Note 6) COM_ _ Off-Leakage Current (Note 6)
RON
RFLAT
INO_ _(OFF)
VNO_ _ or VS_= 4.5V, TA = +25C ICOM_ _(OFF) 1V; VCOM_ _ = 1V, TA = TMIN to TMAX 4.5V; V+ = 5.25V VNO_ _ or VS_ = 4.5V, 1V, or floating; VCOM_ _ = 4.5V, 1V; V+ = 5.25V TA = +25C
COM_ _On-Leakage Current (Note 6) AUDIO PERFORMANCE Total Harmonic Distortion plus Noise Off-Isolation (Note 7) Channel-to-Channel Crosstalk
ICOM_ _(ON)
THD+N
fIN = 1kHz, VNO_ _ or VS_ = 1VRMS + 2.5VDC
RL = 600 RL =10k
0.07 % 0.006 -85 -85 dB dB
VISO(A) VCT(A)
VNO_ _ = 1VRMS, fIN = 20kHz, RL = 600, S_ = GND, shunt switch on or off VNO_ _ = 1VRMS, fIN = 20kHz, RL = RS = 600
2
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Serially Controlled, Triple 3x2 Audio/Video Crosspoint Switches
ELECTRICAL CHARACTERISTICS--Single +5V Supply (continued)
(V+ = +5V 5%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) (Note 2) PARAMETER VIDEO PERFORMANCE Off-Isolation (Note 7) VISO(V) VNO_ _ or VS_ = 1VRMS, fIN = 10MHz, RL = 50, RS =50, S_ = GND Shunt switch on Shunt switch off -72 dB -62 -55 250 10 200 400 500 100 200 ns 250 10 50 ns dB MHz pF SYMBOL CONDITIONS MIN TYP MAX UNITS
MAX4548/MAX4549
Channel-to-Channel Crosstalk -3dB Bandwidth Off-Capacitance
VCT(V) BW COFF(NO)
VNO_ _ or VS_ = 0.5VRMS, RS = 50, fIN = 10MHz, RL = 50, RS = 50, RL = 50 f = 1MHz VNO_ _ or VS_ = 2.5V, TA = +25C RL = 5k, CL = 35pF TA = TMIN to TMAX VNO_ _ or VS_ = 2.5V, TA = +25C RL = 300, TA = TMIN to TMAX CL = 35pF VNO_ _ or VS_ = 2.5V VNO_ _ or VS_ = 2.5V, RL = 5k, CL = 35pF, TA = +25C VNO_ _ or VS_ = 2.5V, RL = 300, CL = 35pF, TA = +25C
DYNAMIC TIMING WITH CLICKLESS MODE DISABLED (Note 8, Figure 1) Turn-On Time tONSD ns
Turn-Off Time Break-Before-Make Time
tOFFSD tBBM
DYNAMIC TIMING WITH CLICKLESS MODE ENABLED (Note 8, Figure 1) Turn-On Time Turn-Off Time BIAS NETWORKS Bias Network Resistance POWER SUPPLIES Supply Voltage Range Supply Current (Note 9) V+ I+ All logic inputs = GND or V+ 2.7 6 5.5 10 V A RBIAS 110 k tONSE tOFFSE 12 3 ms ms
ELECTRICAL CHARACTERISTICS--Single +3V Supply
(V+ = +3V 10%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) (Note 2) PARAMETER ANALOG SWITCHES Analog Signal Range (Note 3) VNO_ _, VCOM_ _, VS_ RON ICOM_ _ = 4mA, VNO_ _ or VS_= 1V, V+ = 2.7V ICOM_ _ = 4mA, VNO_ _ or VS_= 1V, V+ = 2.7V ICOM_ _ = 4mA; V+ = 2.7V; VNO_ _ = 1V, 1.5V, 2V TA = +25C TA = TMIN to TMAX TA = +25C TA = TMIN to TMAX TA = +25C TA = TMIN to TMAX 3 5 0 40 V+ 60 80 7 8 6 8 3 V SYMBOL CONDITIONS MIN TYP MAX UNITS
On-Resistance COM_ _ to NO_ _ or S_ On-Resistance Match Between Channels (Note 4) COM_ _ to NO_ _ or S_ On-Resistance Flatness (Note 5)
RON
RFLAT
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Serially Controlled, Triple 3x2 Audio/Video Crosspoint Switches MAX4548/MAX4549
ELECTRICAL CHARACTERISTICS--Single +3V Supply (continued)
(V+ = +3V 10%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) (Note 2) PARAMETER NO_ _ or S_ Off-Leakage Current (Notes 6, 10) COM _ Off-Leakage Current (Notes 6, 10) SYMBOL INO_ _(OFF) CONDITIONS VNO_ _ or VS_ = 3V, 0.5V; VCOM_ _ = 0.5V, 3V; V+ = 3.6V TA = +25C TA = TMIN to TMAX TA = +25C TA = TMIN to TMAX TA = +25C TA = TMIN to TMAX MIN -2 -10 -2 -10 -2 -10 0.04 0.04 TYP 0.04 MAX 2 nA 10 2 nA 10 2 nA 10 UNITS
VNO_ _ or VS_ = 3V, ICOM_ _(OFF) 0.5V; VCOM_ _ = 0.5V, 3V; V+ = 3.6V VNO_ _ or VS_ = 0.5V, 3V, or floating; ICOM_ _(ON) VCOM_ _ = 0.5V, 3V; V+ = 3.6V
COM _ On-Leakage Current (Notes 6, 10) AUDIO PERFORMANCE Total Harmonic Distortion plus Noise
THD+N
fIN = 1kHz, VNO_ _ or VS_ = 1.5VDC + 0.5VRMS
RL = 600 RL = 10
0.1 % 0.01 -85 dB
Off-Isolation (Note 7)
VISO(A)
VNO_ _ = 0.5VRMS, fIN = 20kHz, RL = 600, S- = GND, shunt switch on or off VNO_ _ = 0.5VRMS, fIN = 20kHz, RL = 600k, RS = 600
Channel-to-Channel Crosstalk VIDEO PERFORMANCE
VCT(A)
-85
dB
Off-Isolation (Note 7)
VISO(V)
VNO_ _ or VS _ = 0.5VRMS, fIN = 10MHz, RL = 50, RS = 50
Shunt switch on Shunt switch off
-72 dB -62 -55 200 10 dB MHz pF
Channel-to-Channel Crosstalk -3dB Bandwidth Off-Capacitance
VCT(V) BW COFF(NO)
VNO_ _ or VS_ = 0.5VRMS, RS = 50, fIN = 10MHz, RL = 50 RS = 50, RL = 50 f = 1MHz
DYNAMIC TIMING WITH CLICKLESS MODE DISABLED (Notes 8 and 12, Figure 1) Turn-On Time tONSD VNO_ _ or VS_ = 1.5V, RL = 5k, CL = 35pF TA = +25C TA = TMIN to TMAX 200 400 800 ns 1000 350 ns 500 10 100 12 3 110 ns ms ms k
Turn-Off Time Break-Before-Make Time Turn-On Time Turn-Off Time BIAS NETWORK Bias Network Resistance
tOFFSD tBBM tONSE tOFFSE RBIAS
TA = +25C VNO_ _ or VS_ = 1.5V, RL = 300, CL = 35pF T = T A MIN to TMAX VNO_ _ or VS_ = 1.5V VNO_ _ or VS_ = 1.5V, RL = 5k, CL = 35pF VNO_ _ or VS_ = 1.5V, RL = 300, CL = 35pF
DYNAMIC TIMING WITH CLICKLESS MODE ENABLED (Notes 8 and 12, Figure 1)
4
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Serially Controlled, Triple 3x2 Audio/Video Crosspoint Switches
I/O INTERFACE CHARACTERISTICS
(V+ = +2.7V to +5.25V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX 0.8 0.6 3 2 0.2 Digital inputs = GND or V+ f = 1MHz ISINK = 6mA ISOURCE = 0.5mA V+ - 0.5 -1 0.001 5 0.4 1 UNITS DIGITAL INPUTS (SCLK, DIN, CS, SCL, SDA, A0, A1) V+ = 5V Input Low Voltage VIL V+ = 3V Input High Voltage Input Hysteresis Input Leakage Current Input Capacitance DIGITAL OUTPUTS (DOUT, SDA) Output Low Voltage DOUT Output High Voltage VOL VOH V V VIH VHYST ILEAK CIN V+ = 5V V+ = 3V
MAX4548/MAX4549
V V V A pF
2-WIRE TIMING CHARACTERISTICS (Figure 3)
(V+ = +2.7V to +5.25V, fSCL = 100kHz, TA = TMIN to TMAX, unless otherwise noted.) PARAMETER SCL Clock Frequency Bus-Free Time between Stop and Start Condition Hold Time After Start Condition Pulse Width of Suppressed Spike (Note 3) STOP Condition Setup Time Data Hold Time Data Setup Time Clock Low Period Clock High Period SCL/SDA Rise Time (Note 11) SCL/SDA Fall Time (Note 11) tSU:STO tHD:DAT tSU:DAT tLOW tHIGH tR tF SYMBOL fSCL tBUF tHD:STA CONDITIONS V+ = 4.75V to 5.25V V+ = 2.7V to 5.25V MIN 0 0 4.7 4 0 4 0 250 4.7 4 20 + 0.1Cb 20 + 0.01Cb 300 300 50 TYP MAX 400 100 UNITS kHz s s ns s s ns s s ns ns
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5
Serially Controlled, Triple 3x2 Audio/Video Crosspoint Switches MAX4548/MAX4549
3-WIRE TIMING CHARACTERISTICS (Figure 5)
(V+ = +2.7V to +5.25V, TA = TMIN to TMAX, unless otherwise noted.) PARAMETER Operating Frequency DIN to SCLK Setup DIN to SCLK Hold SCLK Fall to Output Data Valid CS to SCLK Rise Setup CS to SCLK Rise Hold CS Pulse Width High SCLK Pulse Width High SCLK Pulse Width Low Rise Time (SCLK, DIN, CS) Fall Time (SCLK, DIN, CS) Note 2: Note 3: Note 4: Note 5: SYMBOL fOP tDS tDH tDO tCSS tCSH tCSW tCH tCL tR tF CLOAD = 50pF 100 0 40 200 200 2 2 CONDITIONS V+ = 4.75V to 5.25V V+ = 2.7V to 5.25V MIN 0 0 100 0 200 TYP MAX 10 2.1 UNITS MHz ns ns ns ns ns ns ns ns s s
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 = +25C. 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 300 load to ground. Turn-on time is defined at the output of the switch for a 0.5V change and measured with a 5k 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.
Typical Operating Characteristics
(V+ = +5V, TA = +25C, unless otherwise noted.)
ON-RESISTANCE vs. VCOM
MAX4548 toc01
ON-RESISTANCE vs. VCOM AND TEMPERATURE
26 24 RDS (ON) () 22 20 TA = +25C 18 TA = +85C TA = +70C
MAX4548 toc02
LEAKAGE CURRENT vs. TEMPERATURE
MAX4548 toc03
40
28
10,000
V+ = 2.7V
LEAKAGE CURRRENT (pA)
35 RDS (ON) ()
1000
30 V+ = 3.3V 25
100 COM_ON 10 COM_OFF
20
1 V+ = 5.0V 16 14 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 VCOM (V) 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 VCOM (V) TA = -40C 0.1 -40 -20 0 20 40 60 80 TEMPERATURE (C) NO_OFF
15
6
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Serially Controlled, Triple 3x2 Audio/Video Crosspoint Switches
Typical Operating Characteristics (continued)
(V+ = +5V, TA = +25C, unless otherwise noted.) TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY
600 IN AND OUT SIGNAL = 1VRMS
MAX4548 toc06
MAX4548 toc05
MAX4548/MAX4549
SUPPLY CURRENT vs. TEMPERATURE
MAX4548 toc04
CHARGE INJECTION vs. VCOM
3 V+ = 5V 2 1 Q (pC) V+ = 3.3V 0 -1 -2 -3
6.8 . 6.6 6.4 SUPPLY CURRENT (A) 6.2 6.0 5.8 5.6 5.4 5.2 5.0 4.8 -40 -20 0 20 40 60 80 TEMPERATURE (C)
1
THD+N (%)
0.1
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 VCOM
0.01 10 100 1000 FREQUENCY (Hz) 10,000 100,000
VIDEO FREQUENCY CHARACTERISTICS
MAX4548 toc07
AUDIO FREQUENCY CHARACTERISTICS
600 IN AND OUT -20 -40 LOSS (dB) -60 OFF-ISOLATION -80 CROSSTALK
MAX4548 toc08
0 -10 -20 -30 LOSS (dB) -40 -50 -60 -70 -80 -90 -100 0.5 1 10 OFF-ISOLATION (WITHOUT SHUNT) OFF-ISOLATION (WITH SHUNT) CROSSTALK ALL-HOSTILE CROSSTALK
0
-100
100
-120 10 100 1k FREQUENCY (Hz) 10k 100k
FREQUENCY (MHz)
VIDEO FREQUENCY RESPONSE
MAX4548 toc09
AUDIO FREQUENCY RESPONSE
-0.01 -0.02 -0.03
LOSS (dB)
MAX4548toc10
0 2 4 LOSS (dB) 6 8 10 50 IN AND OUT 12 0.1 1 10 FREQUENCY (MHz) 100
0
-0.04 -0.05 -0.06 -0.07 -0.08 -0.09 -0.10 RIN = ROUT = 50 10 100 1k FREQUENCY (Hz) 10k 100k
1000
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7
Serially Controlled, Triple 3x2 Audio/Video Crosspoint Switches MAX4548/MAX4549
Typical Operating Characteristics (continued)
(V+ = +5V, TA = +25C, unless otherwise noted.)
ON/OFF TIME vs. TEMPERATURE (HARD MODE)
TURN-ON TIME, V+ = 3V
MAX4548 toc11
COM RISE TIME (SOFT MODE)
MAX4548toc12
300 250 200 TIME (ns) TURN-ON TIME, V+ = 5V 150 100 50 0 -40 -20 0 20 40 60 80 TEMPERATURE (C) TURN-OFF TIME, V+ = 3V
VCOM (1V/div)
TURN-OFF TIME, V+ = 5V
0
100s/div
COM FALL TIME (SOFT MODE)
MAX4548toc13
COM TURN-ON TIME (HARD MODE)
VCS (5V/div) 0
MAX4548toc14
VCOM (1V/div)
VCOM (2V/div)
0
0
100s/div
50ns/div
COM TURN-OFF TIME (HARD MODE)
MAX4548toc15
COM ON/OFF TIMES (SOFT MODE)
VCS (5V/div) 0 TURN-OFF TIME VCOM (2V/div) 0
MAX4548 toc16
VCS (5V/div) 0
VCOM (2V/div) 0
VCOM (2V/div) TURN-ON TIME 0 25ns/div 0 2 3 6 8 10 12 14 16 18 20 TIME (ms)
8
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Serially Controlled, Triple 3x2 Audio/Video Crosspoint Switches
Pin Description
PIN MAX4548 1 2 3 4 5 6, 21 7 8 9 10 11 12 13 14 15, 16, 32 17 - 18 - 19 - 20 - 22 23 24 25 MAX4549 1 2 3 4 5 6, 21 7 8 9 10 11 12 13 14 15, 16, 32 - 17 - 18 - 19 - 20 22 23 24 25 NAME NO1C CBIASH NO2C SC NO3C V+ NO1A NO1B SA NO2A NO2B SB NO3A NO3B GND SDA DIN SCL SCLK A1 DOUT A0 CS ABIASL ABIASH MID4 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. Input 1 to Crosspoint A Input 1 to Crosspoint B 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. Input 2 to Crosspoint A Input 2 to Crosspoint B 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. Input 3 to Crosspoint A Input 3 to Crosspoint B Ground 2-Wire Serial-Interface Data Input. Data is clocked in on SCL's rising edge. 3-Wire Serial-Interface Data Input. Data is clocked in on SCLK's rising edge. 2-Wire Serial-Interface Clock Input 3-Wire Serial-Interface Clock Input 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. LSB of 2-Wire Serial-Interface Address Field 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. 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). 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). Audio Bypass for SA and SB Inputs Output 2 of Crosspoint B 9 FUNCTION
MAX4548/MAX4549
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Serially Controlled, Triple 3x2 Audio/Video Crosspoint Switches
10
Figure 1. Switching Times
MAX4548/MAX4549
MAX4548
36
35
34
33
31
30
29
28
27
26
______________________________________________________________________________________ PIN MAX4549
P VNO_ _
MAX4548 MAX4549
CL INCLUDES FIXTURE AND STRAY CAPACITANCE. VOUT = VCOM [RL / (RL + RON)]
36
35
34
33
31
30
29
28
27
26
2 OR 3
SERIAL INTERFACE
NO_ _
COM1C
COM2C
COM1A
COM1B
COM2A
CBIASL
DECODER/ CONTROLLER
NAME
MID5
MID1
MID2
MID3
GND
V+
V+
COM _
10nF
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).
Output 1 of Crosspoint C
Video Bypass for All Inputs to Crosspoint C
Output 2 of Crosspoint C
Output 1 of Crosspoint A
Audio Bypass for IN1A and IN1B Inputs
Output 1 of Crosspoint B
Audio Bypass for IN2A and IN2B Inputs
Output 2 of Crosspoint A
Audio Bypass for IN3A and IN3B Inputs
RL 300
CL 35pF
VOUT
2-WIRE
3-WIRE
CS
FUNCTION
SCL
Pin Description (continued)
VOUT VOUT VOUT VOUT 3V 3V 0 0 0 0 0 50% 50% tOFF tON tON +0.5V VOUT - 0.5V 0.9 * VOUT ACKNOWLEDGE BIT tR > 20ns tF > 20ns
0
tOFF 0.1 * VOUT
Serially Controlled, Triple 3x2 Audio/Video Crosspoint Switches MAX4548/MAX4549
V+/2
MAX4548 MAX4549
RS NO1_ COM1_ COM2_ SIGNAL GENERATOR 2/3
VOUT RL ANALYZER ANALYZER RL V+/2 10k 10k
DECODER/ ENCODER
V+ 10nF GND S_
1F
10k VIN
Figure 2a. Off-Isolation
RS RS
VIN
10k SIGNAL GENERATOR 10k SIGNAL GENERATOR 10k VOUT
MAX4548 MAX4549
Figure 2c. All-Hostile Crosstalk
Detailed Description
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 35 max on-resistance, 7 onresistance matching between channels, 5 on-resistance flatness, and as low as 0.07% total harmonic distortion.
11
10k
MAX4548 MAX4549
10k
Figure 2b. Crosstalk
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Serially Controlled, Triple 3x2 Audio/Video Crosspoint Switches MAX4548/MAX4549
Table 1. Command-Byte Format
BIT C7 C6 C5 C4 C3 C2 C1 C0 Bias COM2C COM1C COM2B COM1B COM2A COM1A D7 D6 D5 D4 D3 D2 D1 D0 Don't care Don't care Don't care Don't care Controls the switch connected to S_; 1 = close switch, 0 = open switch. Controls the switch connected to NO3_; 1 = close switch, 0 = open switch. Controls the switch connected to NO2_; 1 = close switch, 0 = open switch. Controls the switch connected to NO1_; 1 = close switch, 0 = open switch. REGISTER Clickless Mode BIT DESCRIPTION
Table 2. COM Data-Byte Format (C0, C1, C2, C3, C4, C5 = "1")
POWER-UP DEFAULT STATE -- -- -- -- 1 0 0 0
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.
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 SRT
A7
A0 ACK
C7
C0 ACK
D7
D0 ACK STOP
Figure 3. 2-Wire Serial-Interface Timing Diagram ("WriteByte'')
SCL
SDA SRT
A7
A0 ACK
C7
C0 ACK
D15
D8 ACK
D7
D0 ACK STOP
Figure 4. 2-Wire Serial-Interface Timing Diagram ("WriteWord'')
12 ______________________________________________________________________________________
Serially Controlled, Triple 3x2 Audio/Video Crosspoint Switches MAX4548/MAX4549
Command-Byte and Data-Byte Programming
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 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
A
tLOW
B
tHIGH
C
D
E
F
G
H
I
J
SCL
SDA
tSU:STA tHD:STA
tSU:DAT
tHD:DAT 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
tSU:STO tBUF
A = START CONDITION B = MSB OF ADDRESS BYTE C = LSB OF ADDRESS BYTE D = ACKNOWLEDGE CLOCKED INTO MASTER E = MSB OF COMMAND BYTE
Figure 5. 2-Wire Serial-Interface Timing Details
Table 3. Bias Data-Byte (C6 = "1")
BIT D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 Don't care Don't care Don't care Don't care Controls SC bias resistors; 1 = connect bias resistors, 0 = disconnect bias resistors. Controls NO3C bias resistors; 1 = connect bias resistors, 0 = disconnect bias resistors. Controls NO2C bias resistors; 1 = connect bias resistors, 0 = disconnect bias resistors. Controls NO1C bias resistors; 1 = connect bias resistors, 0 = disconnect bias resistors. Controls SB bias resistors; 1 = connect bias resistors, 0 = disconnect bias resistors. Controls SA bias resistors; 1 = connect bias resistors, 0 = disconnect bias resistors. Controls NO3B bias resistors; 1 = connect bias resistors, 0 = disconnect bias resistors. Controls NO3A bias resistors; 1 = connect bias resistors, 0 = disconnect bias resistors. Controls NO2B bias resistors; 1 = connect bias resistors, 0 = disconnect bias resistors. Controls NO2A bias resistors; 1 = connect bias resistors, 0 = disconnect bias resistors. Controls NO1B bias resistors; 1 = connect bias resistors, 0 = disconnect bias resistors. Controls NO1A bias resistors; 1 = connect bias resistors, 0 = disconnect bias resistors. DESCRIPTION POWER-UP DEFAULT STATE - - - - 1 1 1 1 1 1 1 1 1 1 1 1 13
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Serially Controlled, Triple 3x2 Audio/Video Crosspoint Switches MAX4548/MAX4549
Table 4. Clickless Mode Format (C7 = "1")
BIT D7 D6 D5 D4 D3 D2 D1 D0 Don't care Don't care Controls COM2C clickless mode; 1 = enables clickless mode, 0 = disables clickless mode. Controls COM1C clickless mode; 1 = enables clickless mode, 0 = disables clickless mode. Controls COM2B clickless mode; 1 = enables clickless mode, 0 = disables clickless mode. Controls COM1B clickless mode; 1 = enables clickless mode, 0 = disables clickless mode. Controls COM2A clickless mode; 1 = enables clickless mode, 0 = disables clickless mode. Controls COM1A clickless mode; 1 = enables clickless mode, 0 = disables clickless mode. DESCRIPTION POWER-UP DEFAULT STATE -- -- 1 1 1 1 1 1
Table 5. "WriteByte" Protocol
ADDRESS BYTE A7 A6 A5 A4 A3 A2 A1 A0 S R T 1 0 0 1 1 A1 A0 0 A C K COMMAND BYTE C7 C6 C5 C4 C3 C2 C1 C0 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 DATA BYTE D7 D6 D5 D4 D3 D2 D1 D0 A C K S T O P
SRT = Start Condition ACK = Acknowledge Condition STOP = Stop Condition
Table 6. "WriteWord" Protocol
ADDRESS BYTE A7 A6 A5 A4 A3 A2 A1 A0 S R T 1 0 0 1 1 A1 A0 0 A C K COMMAND BYTE C7 C6 C5 C4 C3 C2 C1 C0 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 DATA WORD D15 D14 D13 D12 D11 D10 D9 D8 A C K D7 D6 D5 D4 D3 D2 D1 D0 A C K S T O P
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 ______________________________________________________________________________________
Serially Controlled, Triple 3x2 Audio/Video Crosspoint Switches MAX4548/MAX4549
CS
SCLK 1 DIN C7 COMMAND BYTE C0 D15 DATA BYTE 24 D0
Figure 6. 3-Wire Serial-Interface Communication
CS
***
tCSH SCLK
tCSS
tCL
tCH
tCSH
*** tDS tDH
DIN tDV DOUT
*** tDO *** tTR
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.
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15
Serially Controlled, Triple 3x2 Audio/Video Crosspoint Switches MAX4548/MAX4549
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.
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.
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.
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.
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.
Bypass Capacitors
The MAX4548/MAX4549 have five bypass pins for the internal bias resistor networks (MID_). The equivalent AC impedance at these pins is 10k. To improve crosstalk performance, bypass MID_ pins with 10F. For lowest cost, standard aluminum electrolytic capacitors in parallel with 0.1F ceramic chip capacitors perform well in audio applications. For computer audio applications, a single 1F capacitor is sufficient. For telecom voice applications, a 0.1F capacitor is adequate. For video applications, bypass MID_ with 0.1F in parallel with 1000pF. This provides a low impedance across the entire video bandwidth.
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
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Serially Controlled, Triple 3x2 Audio/Video Crosspoint Switches MAX4548/MAX4549
Functional Diagram
NO1A NO2A NO3A SA
7 10 13 9 SWITCH MATRIX A
31 27
COM1A COM2A
MAX4548 MAX4549
NO1B NO2B NO3B SB
8 11 14 12 SWITCH MATRIX B
29 25
COM1B COM2B
NO1C NO2C NO3C SC
1 3 5 4 SWITCH MATRIX C
35 33
COM1C COM2C
19 20
A1 (DOUT) A0 (CS) SCL (SCLK) SDA (DIN)
V+ GND
6, 21 15, 16, 32
CONTROL LOGIC
18 17
ABIASH CBIASH
23 2 BIAS RESISTOR NETWORK
22 36
ABIASL CBIASL
MID1 MID2 MID3
30 28 26
34 24
MID5 MID4
( ) ARE FOR MAX4549
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17
Serially Controlled, Triple 3x2 Audio/Video Crosspoint Switches MAX4548/MAX4549
________________________________________________________Package Information
SSOP.EPS
Chip Information
TRANSISTOR COUNT: 7700 SUBSTRATE IS INTERNALLY CONNECTED TO V+.
18
______________________________________________________________________________________
Serially Controlled, Triple 3x2 Audio/Video Crosspoint Switches MAX4548/MAX4549
NOTES
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19
Serially Controlled, Triple 3x2 Audio/Video Crosspoint Switches MAX4548/MAX4549
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 (c) 1999 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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