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19-1232; Rev 0; 6/97
Quad/Dual, Low-Voltage, Bidirectional RF/Video Switches
_______________General Description
The MAX4545/MAX4546/MAX4547 are low-voltage T-switches designed for switching RF and video signals from DC to 300MHz in 50 and 75 systems. The MAX4545 contains four normally open single-pole/singlethrow (SPST) switches. The MAX4546 contains two dual SPST switches (one normally open, one normally closed.) The MAX4547 contains two single-pole/double-throw (SPDT) switches. Each switch is constructed in a "T" configuration, ensuring excellent high-frequency off isolation and crosstalk of -80dB at 10MHz. They can handle Rail-to-Rail(R) analog signals in either direction. On-resistance (20 max) is matched between switches to 1 max and is flat (0.5 max) over the specified signal range, using 5V supplies. The off leakage current is less than 5nA at +25C and 50nA at +85C. These CMOS switches can operate with dual power supplies ranging from 2.7V to 6V or a single supply between +2.7V and +12V. All digital inputs have 0.8V/2.4V logic thresholds, ensuring both TTL- and CMOS-logic compatibility when using 5V or a single +5V supply.
____________________________Features
o Low 50 Insertion Loss: -1dB at 100MHz o High 50 Off Isolation: -80dB at 10MHz o Low 50 Crosstalk: -80dB at 10MHz o DC to 300MHz -3dB Signal Bandwidth o 20 Signal Paths with 5V Supplies o 1 Signal-Path Matching with 5V Supplies o 0.5 Signal-Path Flatness with 5V Supplies o 2.7V to 6V Dual Supplies +2.7V to +12V Single Supply o Low Power Consumption: <1W o Rail-to-Rail Bidirectional Signal Handling o Pin Compatible with Industry-Standard DG540, DG542, DG643 o >2kV ESD Protection per Method 3015.7 o TTL/CMOS-Compatible Inputs with Single +5V or 5V
MAX4545/MAX4546/MAX4547
________________________Applications
RF Switching Video Signal Routing High-Speed Data Acquisition Test Equipment ATE Equipment Networking
TOP VIEW
IN1 1 COM1 2 GND1 3 N01 4 V- 5 GND5 6 N04 7 GND4 8 COM4 9 IN4 10 20 IN2 19 COM2 18 GND2 17 NO2 16 V+ IN1 1 COM1 2 GND1 3 N01 4 V- 5 NC4 6 GND4 7 COM4 8
______________Ordering Information
PART MAX4545CPP MAX4545CWP TEMP. RANGE 0C to +70C 0C to +70C PIN-PACKAGE 20 Plastic DIP 20 Wide SO
Ordering Information continued at end of data sheet.
_____________________Pin Configurations/Functional Diagrams/Truth Tables
MAX4546 MAX4547
16 IN2 15 COM2 14 GND2 13 NO2 12 V+ 11 NC3 10 GND3 9 COM3
IN1 1 N01 2 V- 3 GND1 4 COM1 5 GND4 6 V+ 7 NC1 8
16 N02 15 V+ 14 GND2 13 COM2 12 GND3 11 V10 NC2 9 IN2
MAX4545
15 GND6 14 N03 13 GND3 12 COM3 11 IN3
DIP/SO/SSOP
MAX4545 LOGIC SWITCH SWITCHES SHOWN FOR LOGIC "0" INPUT 0 1 OFF ON LOGIC 0 1
DIP/SO/QSOP
MAX4546 1, 2 OFF ON 3, 4 ON OFF LOGIC 0 1
DIP/SO/QSOP
MAX4547 NO-COM OFF ON NC-COM ON OFF
Rail-to-Rail is a registered trademark of Nippon Motorola Ltd.
________________________________________________________________ Maxim Integrated Products 1
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Quad/Dual, Low-Voltage, Bidirectional RF/Video Switches MAX4545/MAX4546/MAX4547
ABSOLUTE MAXIMUM RATINGS
(Voltages Referenced to GND) V+ ...........................................................................-0.3V, +13.0V V- ............................................................................-13.0V, +0.3V V+ to V-...................................................................-0.3V, +13.0V All Other Pins (Note 1) ..........................(V- - 0.3V) to (V+ + 0.3V) Continuous Current into Any Terminal..............................25mA Peak Current into Any Terminal (pulsed at 1ms, 10% duty cycle)..................................50mA ESD per Method 3015.7 ..................................................>2000V Continuous Power Dissipation (TA = +70C) (Note 2) 16-Pin Plastic DIP (derate 10.53mW/C above +70C) ..........................842mW 16-Pin Narrow SO (derate 8.70mW/C above +70C) ............................696mW 16-Pin QSOP (derate 8.3mW/C above +70C).......... 667mW 20-Pin Plastic DIP (derate 8.0mW/C above +70C) ...640mW 20-Pin Wide SO (derate 10.00mW/C above +70C) .. 800mW 20-Pin SSOP (derate 8.0mW/C above +70C) .......... 640mW Operating Temperature Ranges MAX454_C_ E .....................................................0C to +70C MAX454_E_ E ..................................................-40C to +85C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10sec) .............................+300C
Note 1: Voltages on all other pins exceeding V+ or V- are clamped by internal diodes. Limit forward diode current to maximum current 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--Dual Supplies
(V+ = +4.5V to +5.5V, V- = -4.5V to -5.5V, VINL = 0.8V, VINH = 2.4V, VGND_ = 0V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) PARAMETER ANALOG SWITCH Analog Signal Range Signal-Path On-Resistance Signal-Path On-Resistance Match Between Channels (Note 4) Signal-Path On-Resistance Flatness (Note 5) NO_, NC_ Off Leakage Current (Note 6) COM_ Off Leakage Current (Note 6) COM_ On Leakage Current (Note 6) LOGIC INPUT IN_ Input Logic Threshold High IN_ Input Logic Threshold Low IN_ Input Current Logic High or Low VIN_H VIN_L IINH_, IINL_ VIN_ = 0.8V or 2.4V C, E C, E C, E 0.8 -1 1.5 1.5 0.03 1 2.4 V V A VCOM_, VNO_,VNC_ RON RON RFLAT(ON) INO_(OFF), INC_(OFF) ICOM_(OFF) ICOM_(ON) (Note 3) V+ = 4.5V, V- = -4.5V, VCOM_ = 2V, ICOM_ = 10mA V+ = 4.5V, V- = -4.5V, VCOM_ = 2V, ICOM_ = 10mA V+ = 5V; V- = -5V; VCOM_ = 1V, 0V, -1V; ICOM = 10mA V+ = 5.5V, V- = -5.5V, VCOM_ = 4.5V, VN_ = 4.5V V+ = 5.5V, V- = -5.5V, VCOM_ = 4.5V, VN_ = 4.5V V+ = 5.5V, V- = -5.5V, VCOM_ = 4.5V, VN_ = 4.5V C, E +25C C, E +25C C, E +25C +25C C, E +25C C, E +25C C, E -5 -50 -5 -50 -10 -100 0.04 0.02 0.3 0.02 V14 18 0.5 V+ 20 25 1 1.25 0.5 5 50 5 50 10 100 V nA nA nA SYMBOL CONDITIONS TA MIN TYP (Note 2) MAX UNITS
2
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Quad/Dual, Low-Voltage, Bidirectional RF/Video Switches
ELECTRICAL CHARACTERISTICS--Dual Supplies (continued)
(V+ = +4.5V to +5.5V, V- = -4.5V to -5.5V, VINL = 0.8V, VINH = 2.4V, VGND_ = 0V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) PARAMETER SYMBOL CONDITIONS TA MIN TYP (Note 2) 90 35 MAX UNITS
MAX4545/MAX4546/MAX4547
SWITCH DYNAMIC CHARACTERISTICS Turn-On Time Turn-Off Time Break-Before-Make Time Delay (MAX4546/MAX4547 only) Charge Injection (Note 3) NO_, NC_ Off Capacitance COM_ Off Capacitance tON tOFF tBBM Q CN_(OFF) VCOM_ = 3V, V+ = 5V, V- = -5V, Figure 4 VCOM_ = 3V, V+ = 5V, V- = -5V, Figure 4 VCOM_ = 3V, V+ = 5V, V- = -5V, Figure 5 (Note 3) CL = 1.0nF, VNO_ = 0V, RS = 0, Figure 6 VNO_ = GND, f = 1MHz, Figure 8 MAX4545 +25C MAX4546 6 11.5 +25C 11.5 17 -80 +25C -80 -82 -88 +25C +25C +25C -80 -84 300 0.004 MHz % dB dB pF +25C C, E +25C C, E +25C +25C +25C 15 40 60 6 6 pF 150 150 200 100 120 ns ns ns pC pF
VCOM_ = 0V, CCOM_(OFF) f = 1MHz, Figure 8
COM_ On Capacitance
CCOM_(ON)
MAX4545 VCOM_ = VNO_ = 0V, MAX4546 f = 1MHz, Figure 8 MAX4547 RL = 50, VCOM_ = 1VRMS, f = 10MHz, Figure 7 RL = 50, VCOM_ = 1VRMS, f = 10MHz, Figure 7 Figure 7, RL = 50 VIN = 5Vp-p, f < 20kHz, 600 in and out MAX4545 MAX4546 MAX4547 MAX4545 MAX4546 MAX4547
Off Isolation (Note 7)
VISO
Channel-to-Channel Crosstalk (Note 8) -3dB Bandwidth Distortion POWER SUPPLY Power-Supply Range V+ Supply Current V - Supply Current
VCT BW THD+N
V+, VI+ IV+ = 5.5V, all VIN_ = 0V or V+ V- = -5.5V
C, E +25C C, E +25C C, E
-6 -1 -10 -1 -10 0.05 0.05
+6 1 10 1 10
V A A
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Quad/Dual, Low-Voltage, Bidirectional RF/Video Switches MAX4545/MAX4546/MAX4547
ELECTRICAL CHARACTERISTICS--Single +5V Supply
(V+ = +4.5V to +5.5V, V- = 0V, VINL = 0.8V, VINH = 2.4V, VGND_ = 0V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) PARAMETER ANALOG SWITCH Analog Signal Range Signal-Path On-Resistance Signal-Path On-Resistance Match NO_, NC_ Off Leakage Current (Note 9) COM_ Off Leakage Current (Note 9) COM_ On Leakage Current (Note 9) LOGIC INPUT IN_ Input Logic Threshold High IN_ Input Logic Threshold Low IN_ Input Current Logic High or Low VIN_H VIN_L IINH_, IINL_ VIN_ = 0.8V or 2.4V C, E C, E C, E 0.8 -1 1.5 1.5 0.03 1 2.4 V V A VCOM_, VNO_, VNC_ RON RON INO_(OFF), INC_(OFF) ICOM_(OFF) ICOM_(ON) (Note 3) V+ = 4.5V, VCOM_ = 3.5V, ICOM_ = 1mA V+ = 4.5V, VCOM_ = 3.5V, ICOM_ = 1mA V+ = 5.5V, VCOM_ = 1V, VN_ = 4.5V V+ = 5.5V, VCOM_ = 1V, VN_ = 4.5V V+ = 5.5V; VCOM_ = 1V, 4.5V +25C +25C C, E +25C C, E +25C C, E +25C C, E +25C C, E -5 -50 -5 -50 -10 -100 0.04 0.02 0.02 0 26 V+ 40 60 2 4 5 50 5 50 10 100 V nA nA nA SYMBOL CONDITIONS TA MIN TYP (Note 2) MAX UNITS
SWITCH DYNAMIC CHARACTERISTICS Turn-On Time Turn-Off Time Break-Before-Make Time Delay (MAX4546/MAX4547 only) Charge Injection Off-Isolation (Note 7) Channel-to-Channel Crosstalk (Note 8) POWER SUPPLY V+ Supply Current I+ V+ = 5.5V, all VIN_ = 0V or V+ +25C C, E -1 -10 0.05 1 10 A tON tOFF tBBM Q VISO VCT VCOM_ = 3V, V+ = 5V, Figure 4 VCOM_ = 3V, V+ = 5V, Figure 4 VCOM_ = 3V, V+ = 5V, Figure 5 (Note 3) CL = 1.0nF, VNO = 2.5V, RS = 0, Figure 6 RL = 50, VCOM_ = 1VRMS, f = 10MHz, Figure 7 RL = 50, VCOM_ = 1VRMS, f = 10MHz, Figure 7 +25C C, E +25C C, E +25C +25C +25C +25C 20 70 25 -75 -70 40 130 250 350 100 150 ns ns ns pC dB dB
4
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Quad/Dual, Low-Voltage, Bidirectional RF/Video Switches
ELECTRICAL CHARACTERISTICS--Single +3V Supply
(V+ = +2.7V to +3.6V, V- = 0V, VINL = 0.8V, VINH = 2.4V, VGND_ = 0V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) PARAMETER ANALOG SWITCH Analog Signal Range Signal-Path On-Resistance LOGIC INPUT IN_ Input Logic Threshold High IN_ Input Logic Threshold Low IN_ Input Current Logic High or Low VIN_H VIN_L IINH_, IINL_ (Note 3) (Note 3) VIN_ = 0.8V or 2.4V (Note 3) C, E C, E C, E 0.8 -1 1.0 1.0 1 2.4 V V A VCOM_, VNO_, VNC_ RON (Note 3) V+ = 2.7V, VCOM_ = 1V, ICOM_ = 1mA +25C +25C C, E 0 70 V+ 120 150 V SYMBOL CONDITIONS TA MIN TYP (Note 2) MAX UNITS
MAX4545/MAX4546/MAX4547
SWITCH DYNAMIC CHARACTERISTICS Turn-On Time Turn-Off Time Break-Before-Make Time Delay (MAX4546/MAX4547 only) POWER SUPPLY V+ Supply Current V+ Supply Current Note 2: Note 3: Note 4: Note 5: Note 6: Note 7: Note 8: Note 9: I+ V+ = 3.6V, all VIN_ = 0V or V+ +25C C, E -1 -10 0.05 1 10 A tON tOFF tBBM VCOM_ = 1.5V, V+ = 2.7V, Figure 4 (Note 3) VCOM_ = 1.5V, V+ = 2.7V, Figure 4 (Note 3) VCOM_ = 1.5V, V+ = 2.7V, Figure 5 (Note 3) +25C C, E +25C C, E +25C 15 100 50 300 600 800 150 200 ns ns ns
The algebraic convention is used in this data sheet; the most negative value is shown in the minimum column. Guaranteed by design. RON = RON(MAX) - RON(MIN). Resistance flatness is defined as the difference between the maximum and the minimum value of on-resistance as measured over the specified analog signal range. Leakage parameters are 100% tested at the maximum rated hot temperature and guaranteed by correlation at +25C. Off isolation = 20log10 [VCOM / (VNC or VNO)], VCOM = output, VNC or VNO = input to off switch. Between any two switches. Leakage testing for single-supply operation is guaranteed by testing with dual supplies.
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5
Quad/Dual, Low-Voltage, Bidirectional RF/Video Switches MAX4545/MAX4546/MAX4547
__________________________________________Typical Operating Characteristics
(V+ = +5V, V- = -5V, TA = +25C, GND = 0V, packages are surface mount, unless otherwise noted.)
ON-RESISTANCE vs. VCOM AND TEMPERATURE (DUAL SUPPLIES)
MAX4545 TOC02
ON-RESISTANCE vs. VCOM (DUAL SUPPLIES)
MAX4545 TOC01
ON-RESISTANCE vs. VCOM (SINGLE SUPPLY)
1000 V- = 0V 25 23 21 19
V+, V- = 1.2V, -1.2V
TA = +125C TA = +85C TA = +25C TA = 0C TA = -55C
RON ()
RON ()
V+, V- = 2.7V, -2.7V
V+, V- = 2V, -2V
V+ = 2.7V 100 V+ = 3.3V V+ = 5V V+ = 7.5V
RON ()
V+ = 2V
17 15 13 11 9 7
V+, V- = 3.3V, -3.3V V+, V- = 5V, -5V 10 -5 -4 -3 -2 -1 0 1 2 3 4 5 VCOM (V) 10 0 1 2 3 4 5 6 7 8 9 10 VCOM (V) V+ = 10V
5 -5 -4 -3 -2 -1 0 1 2 3 4 5 VCOM (V)
ON-RESISTANCE vs. VCOM AND TEMPERATURE (SINGLE SUPPLY)
MAX4545 TOC04
ON/OFF-LEAKAGE CURRENT vs. TEMPERATURE
MAX4545 TOC05
CHARGE INJECTION vs. VCOM
MAX4545 TOC06
45 40 35 RON () 30 TA = +25C 25 20 15 10 0 TA = 0C TA = +125C TA = +85C
10
120 100 80
1 LEAKAGE (nA) ON/OFF LEAKAGE
Qj (pC)
0.1
60 40 20
DUAL SUPPLIES
0.01
0.001 TA = -55C 0.0001 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 VCOM (V) -75 -50 -25 0 25 50 75 100 125 TEMPERATURE (C) 0 -20 -5 -4 -3 -2 -1
SINGLE SUPPLY
0
1
2
3
4
5
VCOM (V)
ON/OFF TIME vs. SUPPLY VOLTAGE
MAX4545 TOC07
ON/OFF TIME vs. TEMPERATURE
100 90 80 tON, tOFF (ns) tON
MAX4545 TOC08
POWER-SUPPLY CURRENT vs. TEMPERATURE
MAX4545 TOC09
250
110
1
200 tON, tOFF (ns)
0.1 I+ I+, I- (A) 0.01 I0.001
150
70 60 50 40 tOFF
100
tON
50 tOFF 0 2 3 4 5 6 8 V+, V- (V)
30 20 10 -75 -50 -25 0 25 50
0.0001
0.00001 75 100 125 -75 -50 -25 0 25 50 75 100 125 TEMPERATURE (C) TEMPERATURE (C)
6
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MAX4545 TOC03
100
Quad/Dual, Low-Voltage, Bidirectional RF/Video Switches
____________________________Typical Operating Characteristics (continued)
(V+ = +5V, V- = -5V, TA = +25C, GND = 0V, packages are surface mount, unless otherwise noted.)
MAX4545/MAX4546/MAX4547
LOGIC-LEVEL THRESHOLD vs. POSITIVE SUPPLY VOLTAGE
MAX4545 TOC10
MAX4545 FREQUENCY RESPONSE
-10 -20 -30 -40 LOSS (dB) -50 -60 -70 -80 -90 -100 -110 -120 OFF ISOLATION V+ = +5V V- = -5V 5V INPUT 50 OUTPUT
MAX14545 TOC11
MAX4546 FREQUENCY RESPONSE
-10 -20 -30 LOSS (dB) -40 -50 -60 -70 OFF ISOLATION V+ = +5V V- = -5V 5V INPUT 50 OUTPUT
MAX4545 TOC12
1.6 1.4 LOGIC-LEVEL THRESHOLD (V) 1.2 1.0 0.8 0.6 0.4 0.2 0 0
0 INSERTION LOSS
0
INSERTION LOSS
CROSSTALK
-80 -90 -100
CROSSTALK
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 V+ (V)
0.1
1
10 FREQUENCY (MHz)
100
1000
1
10
100
1000
FREQUENCY (MHz)
FREQUENCY RESPONSE
10 0 -10 SWITCH LOSS (dB) -20 -30 -40 -50 -60 -70 -80 -90 -100 1 10 100 1000 FREQUENCY (MHz) OFF ISOLATION CROSSTALK ON PHASE ON LOSS 80 60 40 20 0 -20 -40 -60 -80 -100 0.0001 10 ON PHASE (DEGREES) 1 THD (%) 0.1 0.01 0.001 10
MAX4545 TOC13
MAX4547 TOTAL HARMONIC DISTORTION vs. FREQUENCY
V+ = +5V V- = -5V 5Vp-p SIGNAL 600 SOURCE AND LOAD
MAX14545 TOC14
100
100
100
1k FREQUENCY (Hz)
10k
100k
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7
Quad/Dual, Low-Voltage, Bidirectional RF/Video Switches MAX4545/MAX4546/MAX4547
______________________________________________________________Pin Description
PIN NAME MAX4545 1, 10, 11, 20 3, 6, 8, 13, 15, 18 16 5 4, 7, 14, 17 -- 2, 9, 12, 19 MAX4546 1, 16 3, 7, 10, 14 12 5 4, 13 6, 11 2, 8, 9, 15 MAX4547 1, 9 4, 6, 12, 14 7, 15 3, 11 2, 16 8, 10 5, 13 IN_ GND_ V+ VNO_ NC_ COM_ Digital Control Input RF and Logic Ground. Grounds are not internally connected to each other, and should all be connected to a ground plane (see Grounding section). Positive Supply-Voltage Input (analog and digital) Negative Supply-Voltage Input. Connect to ground plane for single-supply operation. Analog Switch Normally Open** Terminals Analog Switch Normally Closed** Terminals Analog Switch Common** Terminals FUNCTION*
* All pins have ESD diodes to V- and V+. ** NO_ (or NC_) and COM_ pins are identical and interchangeable. Either may be considered as an input or output; signals pass equally well in either direction.
_______________Theory of Operation
Logic-Level Translators
The MAX4545/MAX4546/MAX4547 are constructed as high-frequency "T" switches, as shown in Figure 1. The logic-level input, IN_, is translated by amplifier A1 into a V+ to V- logic signal that drives amplifier A2. (Amplifier A2 is an inverter for normally closed switches.) Amplifier A2 drives the gates of N-channel MOSFETs N1 and N2 from V+ to V-, turning them fully on or off. The same signal drives inverter A3 (which drives the P-channel MOSFETs P1 and P2) from V+ to V-, turning them fully on or off, and drives the N-channel MOSFET N3 off and on. The logic-level threshold is determined by V+ and GND_. The voltage on GND_ is usually at ground potential, but it may be set to any voltage between (V+ - 2V) and V-. When the voltage between V+ and GND_ is less than 2V, the level translators become very slow and unreliable. Since individual switches in each package have individual GND_ pins, they may be set to different voltages. Normally, however, they should all be connected to the ground plane.
COM_
NORMALLY OPEN SWITCH CONSTRUCTION N1 D IN_ 0 1 V+ A1 IN_ S GND_ VA1 (NC) BSD DIODES ON GND_, IN_, COM_, NO_, AND NC_ V+ V+ A2 A3 D N3 COM_ - NO_ OFF ON P1 S D S P2 D S D N2 S NO_
Figure 1. T-Switch Construction
Switch On Condition
When the switch is on, MOSFETs N1, N2, P1, and P2 are on and MOSFET N3 is off. The signal path is COM_ to NO_, and because both N-channel and P-channel MOSFETs act as pure resistances, it is symmetrical
8
(i.e., signals may pass in either direction). The off MOSFET, N3, has no DC conduction, but has a small amount of capacitance to GND_. The four on MOSFETs also have capacitance to ground that, together with the series resistance, forms a lowpass filter. All of these capacitances are distributed evenly along the series resistance, so they act as a transmission line rather than a simple R-C filter. This helps to explain the exceptional 300MHz bandwidth when the switches are on.
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Quad/Dual, Low-Voltage, Bidirectional RF/Video Switches
Typical attenuation in 50 systems is -1dB and is reasonably flat up to 100MHz. Higher-impedance circuits show even lower attenuation (and vice versa), but slightly lower bandwidth due to the increased effect of the internal and external capacitance and the switch's internal resistance. The MAX4545/MAX4546/MAX4547 are optimized for 5V operation. Using lower supply voltages or a single supply increases switching time, increases on-resistance (and therefore on-state attenuation), and increases nonlinearity. N-channel and P-channel MOSFET with their sources and drains paralleled and their gates driven out of phase with V+ and V- by the logic-level translators. V+ and GND power the internal logic and logic-level translators, and set the input logic thresholds. The logic-level translators convert the logic levels to switched V+ and V- signals to drive the gates of the analog switches. This drive signal is the only connection between the logic supplies and the analog supplies. All pins have ESD protection to V+ and to V-. Increasing V- has no effect on the logic-level thresholds, but it does increase the drive to the P-channel switches, reducing their on-resistance. V- also sets the negative limit of the analog signal voltage. The logic-level thresholds are CMOS and TTL compatible when V+ is +5V. As V+ is raised, the threshold increases slightly; when V+ reaches +12V, the level threshold is about 3.1V, which is above the TTL output high-level minimum of 2.8V, but still compatible with CMOS outputs.
MAX4545/MAX4546/MAX4547
Switch Off Condition
When the switch is off, MOSFETs N1, N2, P1, and P2 are off and MOSFET N3 is on. The signal path is through the off-capacitances of the series MOSFETs, but it is shunted to ground by N3. This forms a highpass filter whose exact characteristics are dependent on the source and load impedances. In 50 systems, and below 10MHz, the attenuation can exceed 80dB. This value decreases with increasing frequency and increasing circuit impedances. External capacitance and board layout have a major role in determining overall performance.
__________Applications Information
Power-Supply Considerations
Overview The MAX4545/MAX4546/MAX4547 construction is typical of most CMOS analog switches. It has three supply pins: V+, V-, and GND. V+ and V- are used to drive the internal CMOS switches and set the limits of the analog voltage on any switch. Reverse ESD protection diodes are internally connected between each analog signal pin and both V+ and V-. If the voltage on any pin exceeds V+ or V-, one of these diodes will conduct. During normal operation these reverse-biased ESD diodes leak, forming the only current drawn from V-. Virtually all the analog leakage current is through the ESD diodes. Although the ESD diodes on a given signal pin are identical, and therefore fairly well balanced, they are reverse biased differently. Each is biased by either V+ or V- and the analog signal. This means their leakages vary as the signal varies. The difference in the two diode leakages from the signal path to the V+ and V- pins constitutes the analog signal-path leakage current. All analog leakage current flows to the supply terminals, not to the other switch terminal. This explains how both sides of a given switch can show leakage currents of either the same or opposite polarity. There is no connection between the analog signal paths and GND. The analog signal paths consist of an
Bipolar-Supply Operation The MAX4545/MAX4546/MAX4547 operate with bipolar supplies between 2.7V and 6V. The V+ and V- supplies need not be symmetrical, but their sum cannot exceed the absolute maximum rating of 13.0V. Do not connect the MAX4545/MAX4546/MAX4547 V+ pin to +3V and connect the logic-level input pins to TTL logic-level signals. TTL logic-level outputs can exceed the absolute maximum ratings, causing damage to the part and/or external circuits.
CAUTION: The absolute maximum V+ to V- differential voltage is 13.0V. Typical "6-Volt" or "12-Volt" supplies with 10% tolerances can be as high as 13.2V. This voltage can damage the MAX4545/MAX4546/MAX4547. Even 5% tolerance supplies may have overshoot or noise spikes that exceed 13.0V.
Single-Supply Operation The MAX4545/MAX4546/MAX4547 operate from a single supply between +2.7V and +12V when V- is connected to GND. All of the bipolar precautions must be observed. Note, however, that these parts are optimized for 5V operation, and most AC and DC characteristics are degraded significantly when departing from 5V. As the overall supply voltage (V+ to V-) is lowered, switching speed, on-resistance, off isolation, and distortion are degraded. (See Typical Operating Characteristics.)
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9
Quad/Dual, Low-Voltage, Bidirectional RF/Video Switches MAX4545/MAX4546/MAX4547
Single-supply operation also limits signal levels and interferes with grounded signals. When V- = 0V, AC signals are limited to -0.3V. Voltages below -0.3V can be clipped by the internal ESD-protection diodes, and the parts can be damaged if excessive current flows. GND_ should be separated from 0V only if the logiclevel threshold has to be changed. Any GND_ pin not connected to 0V should be bypassed to the ground plane with a surface-mount 10nF capacitor to maintain good RF grounding. DC current in the IN_ and GND_ pins is less than 1nA, but increases with switching frequency. On the MAX4545 only, two extra ground pins--GND5 and GND6--are provided to improve isolation and crosstalk. They are not connected to the logic-level circuit. These pins should always be connected to the ground plane with solid copper.
Power Off When power to the MAX4545/MAX4546/MAX4547 is off (i.e., V+ = 0V and V- = 0V), the Absolute Maximum Ratings still apply. This means that neither logic-level inputs on IN_ nor signals on COM_, NO_, or NC_ can exceed 0.3V. Voltages beyond 0.3V cause the internal ESD-protection diodes to conduct, and the parts can be damaged if excessive current flows.
Grounding
DC Ground Considerations Satisfactory high-frequency operation requires that careful consideration be given to grounding. For most applications, a ground plane is strongly recommended, and all GND_ pins should be connected to it with solid copper. While the V+ and V- power-supply pins are common to all switches in a given package, each switch has separate ground pins that are not internally connected to each other. This contributes to the overall high-frequency performance and provides added flexibility in some applications, but it can cause problems if it is overlooked. All the GND_ pins have ESD diodes to V+ and V-. In systems that have separate digital and analog (signal) grounds, connect these switch GND_ pins to analog ground. Preserving a good signal ground is much more important than preserving a digital ground. Ground current is only a few nanoamps. The logic-level inputs, IN_, have voltage thresholds determined by V+ and GND_. (V- does not influence the logic-level threshold.) With +5V and 0V applied to V+ and GND_, the threshold is about 1.6V, ensuring compatibility with TTL- and CMOS-logic drivers. The various GND_ pins can be connected to separate voltage potentials if any or all of the logic-level inputs is not a normal logic signal. (The GND_ voltages cannot exceed (V+ - 2V) or V-.) Elevating GND_ reduces off isolation. For example, using the MAX4545, if GND2- GND6 are connected to 0V and GND1 is connected to V-, then switches 2, 3, and 4 would be TTL/CMOS compatible, but switch 1 (IN1) could be driven with the railto-rail output of an op amp operating from V+ and V-. Note, however, that IN_ can be driven more negative than GND_, as far as V-. GND_ does not have to be removed from 0V when IN_ is driven from bipolar sources, but the voltage on IN_ should never exceed V-.
10
AC Ground and Bypassing A ground plane is mandatory for satisfactory highfrequency operation. (Prototyping using hand wiring or wire-wrap boards is strongly discouraged.) Connect all 0V GND_ pins to the ground plane with solid copper. (The GND_ pins extend the high-frequency ground through the package wire-frame, into the silicon itself, thus improving isolation.) The ground plane should be solid metal underneath the device, without interruptions. There should be no traces under the device itself. For DIP packages, this applies to both sides of a two-sided board. Failure to observe this will have a minimal effect on the "on" characteristics of the switch at high frequencies, but it will degrade the off isolation and crosstalk.
All V+ and V- pins should be bypassed to the ground plane with surface-mount 10nF capacitors. For DIP packages, they should be mounted as close as possible to the pins on the same side of the board as the device. Do not use feedthroughs or vias for bypass capacitors. For surface-mount packages, the pins are so close to each other that the bypass capacitors should be mounted on the opposite side of the board from the device. In this case, use short feedthroughs or vias, directly under the V+ and V- pins. Any GND_ pin not connected to 0V should be similarly bypassed. If Vis 0V, connect it directly to the ground plane with solid copper. Keep all leads short. The MAX4547 has two V+ and V- pins. Make DC connections to only one of each to minimize crosstalk. Do not route DC current into one of the V+ or V- pins and out the other V+ or V- pin to other devices. The second set of V+ and V- pins is for AC bypassing only. For dual-supply operation, the MAX4547 should have four 10nF bypass capacitors connected to each V+ and V- pin, as close to the package as possible. For single-supply operation, the MAX4547 should have two 10nF bypass capacitors connected (one to each V+ pin), as close to the package as possible.
______________________________________________________________________________________
Quad/Dual, Low-Voltage, Bidirectional RF/Video Switches
V+
Board Layout
82 (194) 12
MAX4545/MAX4546/MAX4547
10nF
LOGIC IN
V+ 1 IN1 IN2 16
2 COM1 3
COM2 15 14
50 IN/OUT
GND1
GND2
IC sockets degrade high-frequency performance and should not be used if signal bandwidth exceeds 5MHz. Surface-mount parts, having shorter internal lead frames, provide the best high-frequency performance. Keep all bypass capacitors close to the device, and separate all signal leads with ground planes. Such grounds tend to be wedge-shaped as they get closer to the device. Use vias to connect the ground planes on each side of the board, and place the vias in the apex of the wedge-shaped grounds that separate signal leads. Logic-level signal lead placement is not critical.
4 NO1 6 NC4
MAX4546
50 OUT/IN
NO2 13 NC3 11
Impedance Matching
The typical on-resistances of the switches in the MAX4545/MAX4546/MAX4547 are 14, but the offstate impedances are approximately equal to a 6pF capacitor. In coaxial systems, therefore, it is impossible to match any impedance for both the on and off state. If impedance matching is critical, the MAX4546 is best suited, since its two sections can be configured as a single on/off switch, as shown in Figure 2. This circuit "wastes" switches and has higher losses, but has better off isolation and maintains good impedance matching in both the on and off states. The resistance values shown in Figure 3 are optimized with 5V supplies for both 50 and 75 systems at room temperature.
7
GND4
GND3
10
8 COM4 V38 (61) 10nF 5
COM3 9 38 (61)
V-
LOGIC 0 1 SWITCHES SHOWN FOR LOGIC "0" INPUT ( ) ARE FOR 75 SYSTEMS.
SWITCH OFF ON
Multiplexer
With its excellent off isolation, the MAX4545 is ideal for use in high-frequency video multiplexers. Figure 3 shows such an application for switching any one of four video inputs to a single output. The same circuit may be used as a demultiplexer by simply reversing the signal direction. Stray capacitance of traces and the output capacitance of switches placed in parallel reduces bandwidth, so the outputs of no more than four individual switches should be placed in parallel if high bandwidth is to be maintained. If more than four mux channels are needed, the 4-channel circuit should be duplicated and cascaded.
Figure 2. Impedance Matching On/Off Switch
On the MAX4545, GND5 and GND6 should always be connected to the ground plane with solid copper to improve isolation and crosstalk.
Signal Routing
Keep all signal leads as short as possible. Separate all signal leads from each other and other traces with the ground plane on both sides of the board. Where possible, use coaxial cable instead of printed circuit board traces.
______________________________________________________________________________________
11
Quad/Dual, Low-Voltage, Bidirectional RF/Video Switches MAX4545/MAX4546/MAX4547
V+
10nF
1 2
1 2
OUT
GND5 GND6
V+
MAX4545
3 4
3 4
MAX4545
1 2 3 4 OUT 50/75 OUT/IN
COM1 GND1 COM2 GND2 COM3 GND3 NO3 50/75 OUT/IN NO2 NO1
MAX4545
ADDRESS DECODING
COM4 GND4 IN1 TO ADDITIONAL MUXES IN2 IN3 IN4 IN1 IN2 IN3 IN4 V10nF NO4
5 6
1 2
OUT
7 8
3 4
MAX4545
VMORE THAN 4 CHANNELS 2 TO 4 CHANNELS
Figure 3. 4-Channel Multiplexer
12
______________________________________________________________________________________
Quad/Dual, Low-Voltage, Bidirectional RF/Video Switches
______________________________________________Test Circuits/Timing Diagrams
10nF +5V
MAX4545/MAX4546/MAX4547
V+ NO_OR NC_
V+ 3V VIN_ 0V 50% 50%
VIN_
MAX4545 MAX4546 MAX4547
IN_ GND_ 50 10nF -5V COM_ VVOUT
90% VOUT 90% 0V RL = 50 tOFF tON
REPEAT TEST FOR EACH SWITCH.
ALL GND_ PINS ARE CONNECTED TO GROUND PLANE (OV). V- IS CONNECTED TO GND (OV) FOR SINGLE-SUPPLY OPERATION.
Figure 4. Switching Time
10nF +5V
V+ * COM3 * COM2 3V
VIN_
MAX4546 * N02
IN_ GND_ 50 10nF -5V 80% VOUT 0V V+ **NC_ **NO_ 1V ALL GND_ PINS ARE CONNECTED TO GROUND PLANE (OV). V+ IS CONNECTED TO GND (OV) FOR SINGLE-SUPPLY OPERATION. tBBM VRL = 50 VIN_ 0V * NC3 VOUT V+ 50% tR < 20ns tF < 20ns
* REPEAT TEST FOR OTHER PAIR OF SWITCHES. 10nF -+5V
VIN_
MAX4547
IN_ GND_ 50 10nF -5V **COM_ VVOUT RL = 50
** REPEAT TEST FOR OTHER SWITCH.
Figure 5. Break-Before-Make Interval (MAX4546/MAX4547 only)
______________________________________________________________________________________ 13
Quad/Dual, Low-Voltage, Bidirectional RF/Video Switches MAX4545/MAX4546/MAX4547
_________________________________Test Circuits/Timing Diagrams (continued)
10nF +5V
V+ NO_ OR NC_
V+ VNO = 0V VIN_ 0V
VIN_
MAX4545 MAX4546 MAX4547
IN_ GND_ 50 10nF -5V COM_ VVOUT CL = 1000pF
VOUT
VOUT
VOUT IS THE MEASURED VOLTAGE DUE TO CHARGE TRANSFER ERROR Q WHEN THE CHANNEL TURNS OFF. Q = VOUT x CL
V- IS CONNECTED TO GND (0V) FOR SINGLE-SUPPLY OPERATION.
Figure 6. Charge Injection
+5V 10nF NETWORK ANALYZER 0V OR V+ IN_ V+ NO_ VIN 50 50
V OFF ISOLATION = 20log OUT VIN V ON LOSS = 20log OUT VIN V CROSSTALK = 20log OUT VIN
MAX4545 MAX4546 MAX4547 COM_
GND_ V-
VOUT
MEAS
REF
50
50
10nF -5V MEASUREMENTS ARE STANDARDIZED AGAINST SHORT AT IC TERMINALS. OFF ISOLATION IS MEASURED BETWEEN COM_ AND "OFF" NO_ OR NC_ TERMINAL ON EACH SWITCH. ON LOSS IS MEASURED BETWEEN COM_ AND "ON" NO_ OR NC_TERMINAL ON EACH SWITCH. CROSSTALK IS MEASURED FROM ONE CHANNEL TO ALL OTHER CHANNELS. SIGNAL DIRECTION THROUGH SWITCH IS REVERSED; WORST VALUES ARE RECORDED. V- IS CONNECTED TO GND (0V) FOR SINGLE-SUPPLY OPERATION.
Figure 7. On Loss, Off Isolation, and Crosstalk
14
______________________________________________________________________________________
Quad/Dual, Low-Voltage, Bidirectional RF/Video Switches
Test Circuits/Timing ______________Diagrams (continued)
10nF +5V
MAX4545/MAX4546/MAX4547
_________________Chip Topographies
MAX4545 COM1 IN1 IN2 COM2
0V OR V+
IN_
V+
NO_ NC_ 1MHz CAPACITANCE ANALYZER
N.C. GND1
GND2 0.101" (2.565mm) NO2 V+ GND6 NO3
MAX4545 MAX4546 MAX4547
GND_ V-
NO1 VGND5 NO4
COM_
10nF -5V ALL GND_ PINS ARE CONNECTED TO GROUND PLANE (0V).
GND3 GND4 N.C.
Figure 8. NO_, NC_, COM_ Capacitance
COM4
IN4 IN3 0.085" (2.159mm)
COM3
MAX4546 COM1 IN1 IN2 COM2 NO1
MAX4547 IN1 IN2 V+
N.C. GND1
GND2 0.101" (2.565mm) NO2
VGND1
GND2 0.101" (2.565mm) N.C.
NO1 VN.C. NC4
V+ N.C. NC3
N.C. N.C. COM1 N.C.
N.C. COM2 N.C.
GND3 N.C. N.C. GND4 V-
GND4
COM4 COM3 0.085" (2.159mm)
GND3
V+
NC1 IN2 0.085" (2.159mm)
NC2
N.C. = NO INTERNAL CONNECTION
TRANSISTOR COUNT: 253 SUBSTRATE INTERNALLY CONNECTED TO V-
______________________________________________________________________________________
15
Quad/Dual, Low-Voltage, Bidirectional RF/Video Switches MAX4545/MAX4546/MAX4547
___________________________________________Ordering Information (continued)
PART MAX4545CAP MAX4545C/D MAX4545EPP MAX4545EWP MAX4545EAP MAX4546CPE MAX4546CSE MAX4546CEE MAX4546C/D MAX4546EPE MAX4546ESE TEMP. RANGE 0C to +70C 0C to +70C -40C to +85C -40C to +85C -40C to +85C 0C to +70C 0C to +70C 0C to +70C 0C to +70C -40C to +85C -40C to +85C PIN-PACKAGE 20 SSOP Dice* 20 Plastic DIP 20 Wide SO 20 SSOP 16 Plastic DIP 16 Narrow SO 16 QSOP Dice* 16 Plastic DIP 16 Narrow SO PART MAX4546EEE MAX4547CPE MAX4547CSE MAX4547CEE MAX4547C/D MAX4547EPE MAX4547ESE MAX4547EEE TEMP. RANGE -40C to +85C 0C to +70C 0C to +70C 0C to +70C 0C to +70C -40C to +85C -40C to +85C -40C to +85C PIN-PACKAGE 16 QSOP 16 Plastic DIP 16 Narrow SO 16 QSOP Dice* 16 Plastic DIP 16 Narrow SO 16 QSOP
*Contact factory for dice specifications.
________________________________________________________Package Information
QSOP.EPS
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.
16 __________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 (408) 737-7600 (c) 1997 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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