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19-4804; Rev 0; 9/02
Fault-Protected, Single 8-to-1/ Dual 4-to-1 Multiplexers
General Description
The MAX4708/MAX4709 8-to-1 and dual 4-to-1 fault-protected multiplexers are pin compatible with the industrystandard DG508/DG509. The MAX4708/MAX4709 are similar to the MAX4508/MAX4509, but these devices do not have clamp diodes to the supply rails on the switch outputs. These multiplexers feature fault-protected inputs, Rail-to-Rail(R) signal-handling capability, and do not require power-supply sequencing. Both devices offer 40V overvoltage protection with the supplies off, 36V protection with the supplies on, and feature 400 (max) on-resistance with 15 (max) matching between channels. The MAX4708/MAX4709 operate with dual supplies of 4.5V to 20V or a single supply of +9V to +36V. All digital inputs have TTL logiccompatible thresholds, ensuring both TTL and CMOS logic compatibility when using a single +12V supply or dual 15V supplies. For low-voltage applications requiring fault protection, refer to the MAX4711/MAX4712/MAX4713 data sheet. o All Channels Off with Power Off o Rail-to-Rail Signal Handling o 400 (max) On-Resistance o 40V Fault Protection with Power Off o 25V Fault Protection with 15V Supplies o 100ns Fault-Response Time o 4.5V to 20V Dual Supplies o +9V to +36V Single Supply o TTL/CMOS-Compatible Logic Inputs
Features
o No Power-Supply Sequencing Required
MAX4708/MAX4709
Ordering Information
PART MAX4708ESE MAX4708EWE MAX4708EPE MAX4709ESE MAX4709EWE MAX4709EPE TEMP RANGE -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C PIN-PACKAGE 16 Narrow SO 16 Wide SO 16 Plastic DIP 16 Narrow SO 16 Wide SO 16 Plastic DIP
Applications
Data-Acquisition Systems Industrial and Process Control Avionics Signal Routing Redundancy/Backup Systems ATE Systems Hot Swap
Rail-to-Rail is a registered trademark of Nippon Motorola, Ltd.
Pin Configurations/Functional Diagrams
TOP VIEW MAX4708
A0 1 EN 2 V- 3 NO1 4 NO2 5 NO3 6 NO4 7 COM 8 LOGIC 16 A1 15 A2 14 GND 13 V+ 12 NO5 11 NO6 10 NO7 9 NO8 A0 1 EN 2 V- 3 NO1A 4 NO2A 5 NO3A 6 NO4A 7 COMA 8 LOGIC
MAX4709
16 A1 15 GND 14 V+ 13 NO1B 12 NO2B 11 NO3B 10 NO4B 9 COMB
SO/DIP
SO/DIP
Pin Configurations/Functional Diagrams continued at end of data sheet. ________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
Fault-Protected, Single 8-to-1/ Dual 4-to-1 Multiplexers MAX4708/MAX4709
ABSOLUTE MAXIMUM RATINGS
(All Voltages Referenced to GND) V+ ........................................................................-0.3V to +44.0V V- .........................................................................-44.0V to +0.3V V+ to V-................................................................-0.3V to +44.0V COM_, A_, EN (Note 1)........................ (V+ + 0.3V) to (V- - 0.3V) NO_.........................................................(V+ - 40V) to (V- + 40V) NO_ to COM_ ..........................................................-36V to +36V NO_ Voltage with Switch Power On ........................-30V to +30V NO_ Voltage with Switch Power Off ........................-40V to +40V Continuous Current into any Terminal. .............................30mA Peak Current into any Terminal (pulsed at 1ms, 10% duty cycle)................................100mA Continuous Power Dissipation (TA = +70C) 16 Narrow SO (derate 8.70mW/C above +70C) .......696mW 16 Plastic DIP (derate 10.53mW/C above +70C) .....842mW 16 Wide SO (derate 9.52mW/C above +70C)...........762mW Operating Temperature Range MAX4708E_ E/MAX4709E_E ...........................-40C to +85C Junction Temperature ..................................................... +150C Storage Temperature Range .............................-65C to +160C Lead Temperature (soldering, 10s) .................................+300C
Note 1: COM_, EN, and A_ pins are not fault protected. Signals on COM_, EN, or A_ 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+ = +15V, V- = -15V, VA_H = +2.4V, VA_L = +0.8V, VEN = +2.4V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) (Note 2)
PARAMETER ANALOG SWITCH Fault-Free Analog Signal Range On-Resistance On-Resistance Match Between Channels NO_ Off-Leakage Current VNO_ RON RON INO_(OFF) (Notes 3, 4) VCOM_ = 10V, INO_ = 0.2mA VCOM_ = 10V, INO_ = 0.2mA (Note 5) VCOM_ = 10V, VNO_ = 10V (Note 6) MAX4708 MAX4709 MAX4708 MAX4709 E +25C E +25C E +25C E +25C E +25C E +25C E +25C E -0.5 -5 -2 -20 -1 -10 -2 -25 -1 -15 V300 V+ 400 500 15 20 +0.5 +5 +2 +20 +1 +10 +2 +25 +1 +15 nA nA V nA SYMBOL CONDITIONS TA MIN TYP MAX UNITS
COM_ Off-Leakage Current
VCOM_ = 10V, ICOM_(OFF) VNO_ = 10V (Note 6)
COM_ On-Leakage Current
VCOM_ = 10V, ICOM_(ON) VNO_ = 10V, or floating (Note 6)
2
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Fault-Protected, Single 8-to-1/ Dual 4-to-1 Multiplexers
ELECTRICAL CHARACTERISTICS--Dual Supplies (continued)
(V+ = +15V, V- = -15V, VA_H = +2.4V, VA_L = +0.8V, VEN = +2.4V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) (Note 2)
PARAMETER FAULT PROTECTION Fault-Protected Analog Signal Range (Notes 3, 4) COM_ Output Leakage Current, Supplies On NO_ Input Leakage Current, Supplies On NO_ Input Leakage Current, Supplies Off Fault-Trip Threshold Fault Output Turn-Off Delay Fault Recovery Time LOGIC INPUT (VEN, VA_) Logic Threshold High Logic Threshold Low Input Leakage Current VIH VIL IIN VA_ = 0.8V or 2.4V VNO_ = 10V, RL = 1k, CL = 35pF, Figure 3 (Note 7) VNO_ = 10V, RL = 1k, CL = 35pF, Figure 3 (Note 7) RL = 1k, CL = 35pF, Figure 2 (Note 7) VNO_ = 5V, RL = 1k, CL = 35pF 0.1% 0.01% E E E +25C E +25C E +25C E E E +25C +25C 10 1 2.5 80 0 -70 170 120 -1 160 2.4 0.8 +1 275 400 200 250 350 500 V V A RL = 10k, VNO_ = 25V RL = 10k, VNO_ = 25V VNO_ ICOM_ INO_ INO_ Power on Power off VNO_ = 25, VEN = 0 VNO_ = 25V, VCOM_ = 10V, VEN = 0 VNO_ = 40V, VCOM = 0, V+ = 0, V- = 0 +25C +25C E +25C E +25C E E +25C +25C -25 -40 -1 -10 -1 -10 -1 -10 V- 0.4 100 1.5 +25 +40 +1 +10 +1 +10 +1 +10 V+ + 0.4 V A A A V ns s SYMBOL CONDITIONS TA MIN TYP MAX UNITS
MAX4708/MAX4709
SWITCH DYNAMIC CHARACTERISTICS Enable Turn-On Time Enable Turn-Off Time Transition Time Settling Time Break-Before-Make Time Delay Charge Injection Off-Isolation tON tOFF tTRANS tSETT tBBM Q VISO ns ns ns s ns pC dB
VNO_ = 10V, RL = 1k, Figure 4 (Note 4) VNO_ = 0, RS = 0, CL = 1.0nF, Figure 5 f = 1MHz, VNO_ = 1VRMS, RL = 75, CL = 15pF, Figure 6 (Note 8)
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3
Fault-Protected, Single 8-to-1/ Dual 4-to-1 Multiplexers MAX4708/MAX4709
ELECTRICAL CHARACTERISTICS--Dual Supplies (continued)
(V+ = +15V, V- = -15V, VA_H = +2.4V, VA_L = +0.8V, VEN = +2.4V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) (Note 2)
PARAMETER Channel-to-Channel Crosstalk NO_ Off-Capacitance COM_ Off-Capacitance COM_ On-Capacitance POWER SUPPLY Power-Supply Range V+ Supply Current V- Supply Current GND Supply Current V+, VI+ IIGND All VA_= 0 or 5V, VNO_ = 0, VEN = 5V All VA_ = 0 or 5V, VNO_ = 0, VEN = 5V All VA_= 0 or 5V, VNO_ = 0, VEN = 5V E +25C E +25C E +25C E 200 200 4.5 370 20.0 525 750 300 400 300 500 V A A A SYMBOL VCT CN_(OFF) CONDITIONS f = 1MHz, VNO_ = 1VRMS, RL = 75, CL = 15pF, Figure 7 (Note 9) f = 1MHz, Figure 8 MAX4708 MAX4709 MAX4708 MAX4709 TA +25C +25C +25C +25C MIN TYP -62 10 19 14 28 22 MAX UNITS dB pF pF pF
CCOM_(OFF) f = 1MHz, Figure 8 CCOM_(ON) f = 1MHz, Figure 8
ELECTRICAL CHARACTERISTICS--Single +12V Supply
(V+ = +12V, V- = 0, VA_H = +2.4V, VA_L = +0.8V, VEN = +2.4V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) (Note 2)
PARAMETER ANALOG SWITCH Fault-Free Analog Signal Range On-Resistance On-Resistance Match Between Channels NO_ Off-Leakage Current VNO_ RON RON INO_(OFF) Power on or off (Note 3) VCOM_ = 10V, INO_ = 0.2mA VCOM_ = 10V, INO_ = 0.2mA (Note 5) VCOM_ = 10V, 1V, VNO_ = 1V, 10V (Notes 6, 10) MAX4708 MAX4709 E +25C E +25C C, E +25C E +25C E +25C E -0.5 -10 -2 -20 -1 -10 0.01 10 -0.3 630 V+ 950 1100 35 50 +0.5 +10 +2 +20 +1 +10 nA V nA SYMBOL CONDITIONS TA MIN TYP MAX UNITS
COM_ Off-Leakage Current
VCOM_ = 10V, 1V, ICOM_(OFF) VNO_ = 1V, 10V (Notes 6, 10)
4
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Fault-Protected, Single 8-to-1/ Dual 4-to-1 Multiplexers
ELECTRICAL CHARACTERISTICS--Single +12V Supply (continued)
(V+ = +12V, V- = 0, VA_H = +2.4V, VA_L = +0.8V, VEN = +2.4V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) (Note 2)
PARAMETER SYMBOL CONDITIONS MAX4708 MAX4709 TA +25C E +25C E MIN -2 -25 -1 -15 -36 -40 -1 -10 -1 -10 -1 -10 2.4 0.8 -1 0.03 240 100 180 1 2.5 50 100 2 5 5 28 +1 500 700 250 350 400 600 TYP MAX +2 +25 +1 +15 +36 +40 +1 +10 +1 +10 +1 +10 nA UNITS
MAX4708/MAX4709
COM_ On-Leakage Current
VCOM_ = 10V, 1V; ICOM_(ON) VNO_ = 10V, 1V, or floating (Notes 6, 10)
FAULT PROTECTION Fault-Protected Analog Signal Range (Notes 3, 10) COM_ Output Leakage Current, Supplies On NO_ Input Leakage Current, Supplies On NO_ Input Leakage Current, Supply Off LOGIC INPUT (VEN, VA_) Logic Threshold High Logic Threshold Low Input Leakage Current VIH VIL IIN VA_ = 0.8V or 2.4V VCOM_ = 10V, RL = 2k, CL = 35pF, Figure 3 (Note 7) VCOM_ = 10V, RL = 2k, CL = 35pF, Figure 3 (Note 7) RL = 2k, CL = 35pF, Figure 2 (Note 7) VNO_ = 5V, RL = 1k, CL = 35pF 0.1% 0.01% E E E +25C E +25C E +25C E E +25C +25C +25C +25C +25C V V A VNO_ ICOM_ INO_ INO_ Power on Power off VNO_ = 36V, V+ = 12V (Notes 3, 10) VNO_ = 36V, VCOM_ = 0, V+ = 12V (Notes 3, 10) VNO_ = 40V, V+ = 0, V- = 0 (Notes 3, 10) E +25C E +25C E +25C E V A A A
SWITCH-DYNAMIC CHARACTERISTICS Enable Turn-On Time Enable Turn-Off Time Transition Time Settling Time Break-Before-Make Time Delay Charge Injection NO_ Off-Capacitance COM_ Off-Capacitance COM_ On-Capacitance tON tOFF tTRANS tSETT tBBM Q CNO_(OFF) ns ns ns s ns pC pF pF pF
VCOM_ = 10V, RL = 2k, Figure 4 (Note 4) VNO_ = 0, RS = 0, CL = 1.0 nF, Figure 5 f = 1MHz, VNO_ = 0, Figure 8
CCOM_(OFF) f = 1MHz, VNO_ = 0, Figure 8 f = 1MHz, VCOM_ = VNO_ = 0, CCOM_(ON) Figure 8
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5
Fault-Protected, Single 8-to-1/ Dual 4-to-1 Multiplexers MAX4708/MAX4709
ELECTRICAL CHARACTERISTICS--Single +12V Supply (continued)
(V+ = +12V, V- = 0, VA_H = +2.4V, VA_L = +0.8V, VEN = +2.4V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) (Note 2)
PARAMETER Off-Isolation Channel-to-Channel Crosstalk POWER SUPPLY Power-Supply Range V+ All VA_ = VEN = 5V, VNO_ = 0 V+ Supply Current I+ E +25C E 112 9 180 36 300 450 250 375 A V SYMBOL VISO VCT CONDITIONS f = 1MHz, VNO_ = 1VRMS, RL = 75, CL = 15pF, Figure 6 (Note 8) f = 1MHz, VNO_ = 1VRMS, RL = 75, CL = 15pF, Figure 7 (Note 9) TA +25C +25C MIN TYP -70 -62 MAX UNITS dB dB
All VA_ = 0 or V+, VNO_ = 0, VEN = +25C 0 or V+ E
Note 2: The algebraic convention is used in this data sheet; the most negative value is shown in the minimum column. Note 3: NO_ pins are fault protected and COM_ pins are not fault protected. The max input voltage on NO_ pins depends on the COM_ load configuration. Generally, the max input voltage is 36V with 15V supplies and a load referred to ground. For more detailed information, see the NO_ Input Voltage section. Note 4: Guaranteed by design and not production tested. Note 5: RON = RON(MAX) - RON(MIN). Note 6: Leakage parameters are 100% tested at the maximum rated hot temperature and guaranteed by correlation at TA = +25C. Note 7: Dynamic testing is 100% functionally tested on the ATE system and correlated with the initial design characterization per Figures 2 and 3. Note 8: Off-Isolation = 20 log10 (VCOM_ / VNO_), where VCOM_ = output and VNO_ = input to open switch. Note 9: Between any two analog inputs. Note 10: Guaranteed by testing with dual supplies.
Typical Operating Characteristics
(V+ = +15V, V- = -15V, VEN = +2.4V, TA = +25C, unless otherwise noted.)
ON-RESISTANCE vs. VCOM (DUAL SUPPLIES)
MAX4708/09 toc01
ON-RESISTANCE vs. VCOM (SINGLE SUPPLY)
MAX4708/09 toc02
ON-RESISTANCE vs. VCOM AND TEMPERATURE (DUAL SUPPLIES)
V+ = +15V V- = -15V TA = +70C 400 RON () 300 200 TA = +125C TA = +85C
MAX4708/09 toc03
1000 V+ = +4.5V V- = -4.5V V+ = +10V V- = -10V V+ = +15V V- = -15V
1000
800
800
RON ()
RON ()
600
600
V+ = +9V V- = 0V V+ = +12V V- = 0V V+ = +15V V- = 0V
600 500
V+ = +20V V- = 0V
400
400
V+ = +30V V- = 0V
200 V+ = +20V V- = -20V 0 -20 -15 -10 -5 0 VCOM (V) 5 10 15 20
200
V+ = +36V V- = 0V 0 6 12 18 VCOM (V) 24 30 36
100 0
TA = +25C TA = -40C -15 -10 -5 0 VCOM (V) 5 TA = -55C 10 15
0
6
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Fault-Protected, Single 8-to-1/ Dual 4-to-1 Multiplexers
Typical Operating Characteristics (continued)
(V+ = +15V, V- = -15V, VEN = +2.4V, TA = +25C, unless otherwise noted.)
MAX4708/MAX4709
ON-RESISTANCE vs. VCOM AND TEMPERATURE (SINGLE SUPPLY)
MAX4708/09 toc04
LEAKAGE CURRENT vs. TEMPERATURE
V+ = +15V, V- = -15V, VCOM = 10V, VNO = 10V ICOM_ON
MAX4708/09 toc05
CHARGE INJECTION vs. VCOM
MAX4708/09 toc06
1000
800
V+ = +12V TA = +125C V- = 0V TA = +70C TA = +85C
1000
10
LEAKAGE CURRENT (pA)
100
5 DUAL SUPPLIES: 15V 0 SINGLE SUPPLY: +12V -5
RON ()
10 ICOM_OFF 1
INO_OFF
400
200
TA = +25C
TA = -40C
TA = -55C 0.1 -10 -40 -15 10 35 60 85 -15 -10 -5 0 VCOM (V) 5 10 15 TEMPERATURE (C)
0 0 2 4 6 VCOM (V) 8 10 12
ENABLE TURN-ON/OFF TIMES vs. SUPPLY VOLTAGE (DUAL SUPPLIES)
MAX4708/09 toc07
ENABLE TURN-ON/OFF TIMES vs. SUPPLY VOLTAGE (SINGLE SUPPLY)
V- = GND, VNO_ = +10V
MAX4708/09 toc08
Q (pC)
600
ENABLE ON/OFF TIMES vs. TEMPERATURE
V+ = +15V V- = -15V
MAX4708/09 toc09
500
VNO_ = 10V
300 250 200 tON 150 100 50 0 tOFF
300 250 200
400 tON/tOFF (ns)
300 tON 200 tOFF 100
tON/tOFF (ns)
tON/tOFF (ns)
tON 150 100 50 0 tOFF
0 0 5 10 15 20 SUPPLY VOLTAGE (V+, V-)
9
18
27
36
-40
-15
10
35
60
85
SUPPLY VOLTAGE (V+)
TEMPERATURE (C)
SUPPLY CURRENT vs. TEMPERATURE (VA_ = 0)
MAX4708/09 toc10
SUPPLY CURRENT vs. TEMPERATURE (VA_ = +5V)
MAX4708/09 toc11
LOGIC-LEVEL THRESHOLD VOLTAGE vs. SUPPLY VOLTAGE
MAX4708/09 toc12
500 400 300 SUPPLY CURRENT (A) 200 100 0 -100 -200 -300 -400 -500 -40 -15
V+ = +15V, V- = -15V, VA_ = 0 I+
600 500 400 SUPPLY CURRENT (A) 300 200 100 0 -100 -200 -300 -400
V+ = +15V, V- = -15V, VA_ = +5V
3.0
THRESHOLD VOLTAGE (V)
I+
2.5
DUAL SUPPLIES 2.0 SINGLE SUPPLY 1.5
IGND
IGND I-
I-
1.0 -40 -15 10 35 60 85 0 5 10 15 20 25 30 35 40 TEMPERATURE (C) SUPPLY VOLTAGE (V)
10
35
60
85
TEMPERATURE (C)
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7
Fault-Protected, Single 8-to-1/ Dual 4-to-1 Multiplexers MAX4708/MAX4709
Typical Operating Characteristics (continued)
(V+ = +15V, V- = -15V, VEN = +2.4V, TA = +25C, unless otherwise noted.)
FAULT CURRENT vs. FAULT VOLTAGE (DUAL SUPPLIES)
MAX4708/09 toc14 MAX4708/09 toc13
FREQUENCY RESPONSE
20 0 -20 ICOM (A) LOSS (dB) -40 CROSSTALK -60 -80 -100 0.001 0.01 0.1 1 10 100 1000 FREQUENCY (MHz) OFF-ISOLATION -100 -150 -200 200 150 100 50 0 -50 V+ = +15V V- = -15V BANDWIDTH
FAULT CURRENT vs. FAULT VOLTAGE (SINGLE SUPPLY)
150 100 ICOM (A) 50 0 -50 -100 V+ = +12V V- = GND
MAX4708/09 toc15
V+ = +15V V- = -15V
200
FOR |VCOM| < VSUPPLY, ICOM = VCOM / RL -80 -60 -40 -20 0 20 40 60
-150 -200 -80 -60 -40 -20
FOR 0V < VCOM < VSUPPLY, ICOM = VCOM / RL 0 20 40 60 80
VCOM (V)
VCOM (V)
INPUT OVERVOLTAGE vs. OUTPUT VOLTAGE
MAX4708/09 toc16
INPUT OVERVOLTAGE vs. OUTPUT VOLTAGE
MAX4708/09 toc17
FAULT RECOVERY TIME (POSITIVE INPUT)
MAX4708/09 toc18
VNO_ INPUT 10V/div GND VNO_ INPUT 10V/div GND VCOM_ OUTPUT 200mV/div GND VCOM_ OUTPUT 10V/div GND VNO_ INPUT 10V/div GND
VCOM_ OUTPUT 5V/div GND
4.00s
200s
1.00s
FAULT RECOVERY TIME (NEGATIVE INPUT)
MAX4708/09 toc19
FAULT RESPONSE TIME (POSITIVE INPUT)
MAX4708/09 toc20
FAULT RESPONSE TIME (NEGATIVE INPUT)
MAX4708/09 toc21
GND VNO_ INPUT 10V/div
VNO_ INPUT 10V/div GND VCOM_ OUTPUT 5V/div GND
GND VNO_ INPUT 10V/div
GND VCOM_ OUTPUT 5V/div
GND VCOM_ OUTPUT 5V/div
1.00s
100ns/div
100ns/div
8
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Fault-Protected, Single 8-to-1/ Dual 4-to-1 Multiplexers
Pin Descriptions
MAX4708 (Single 8-to-1 Mux)
PIN 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 NAME A0 EN VNO1 NO2 NO3 NO4 COM NO8 NO7 NO6 NO5 V+ GND A2 A1 Address Bit 0 Mux Enable Negative Supply Voltage. Bypass to GND with a 0.1F capacitor. Channel Input 1 Channel Input 2 Channel Input 3 Channel Input 4 Analog Output Channel Input 8 Channel Input 7 Channel Input 6 Channel Input 5 Positive Supply Voltage. Bypass to GND with a 0.1F capacitor. Ground Address Bit 2 Address Bit 1 FUNCTION
MAX4708/MAX4709
MAX4709 (Dual 4-to-1 Mux)
PIN 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 NAME A0 EN VNO1A NO2A NO3A NO4A COMA COMB NO4B NO3B NO2B NO1B V+ GND A1 Address Bit 0 Mux Enable Negative Supply Voltage. Bypass to GND with a 0.1F capacitor. Channel Input 1A Channel Input 2A Channel Input 3A Channel Input 4A Mux Output A Mux Output B Channel Input 4B Channel Input 3B Channel Input 2B Channel Input 1B Positive Supply Voltage. Bypass to GND with a 0.1F capacitor. Ground Address Bit 1 FUNCTION
Truth Tables
MAX4708 (Single 8-to-1 Mux)
A2 X 0 0 0 0 1 1 1 1 A1 X 0 0 1 1 0 0 1 1 A0 X 0 1 0 1 0 1 0 1 EN 0 1 1 1 1 1 1 1 1 ON SWITCH None NO1 NO2 NO3 NO4 NO5 NO6 NO7 NO8
MAX4709 (Dual 4-to-1 Mux)
A1 X 0 0 1 1 A0 X 0 1 0 1 EN 0 1 1 1 1 COMA None NO1A NO2A NO3A NO4A COMB None NO1B NO2B NO3B NO4B
X = Don't care.
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9
Fault-Protected, Single 8-to-1/ Dual 4-to-1 Multiplexers MAX4708/MAX4709
Detailed Description
Several unique features differentiate the MAX4708/ MAX4709 from traditional fault-protected multiplexers. First, instead of the three series FETs utilized in older designs, the MAX4708/MAX4709 design employs two parallel FETs for lower on-resistance and improved flatness. Second, older devices limited the range of signal amplitudes the switch could pass by as much as 3V below the supply rails. The MAX4708/MAX4709 feature rail-to-rail signal handling that allows the devices to transmit signals with amplitudes at or slightly beyond the supply rails. Finally, in former designs (MAX4508/ MAX4509), when a fault occurred, the devices clamped and held the output voltage at the appropriate supply rail until the fault was removed. Instead, the MAX4708/MAX4709 now disconnect COM_ from NO_ during a fault condition, making COM_ a high-impedance output as long as the fault is present. Operation is identical for both positive and negative fault polarities. When the NO_ voltage ranges beyond supply rails (fault condition), the NO_ input becomes high impedance, regardless of the switch state or load resistance. If power is removed, and the fault voltage is still present, the NO_ terminals remain high impedance. The fault voltage can be up to 40V, with V+ = V- = 0. The COM_ pins are not fault protected. Limit any voltage sources connected to COM_ to the supply rails. Figure 1 shows the internal construction of a single normally open (NO) switch, with the analog signal paths shown in bold. The parallel combination of N-channel FET N1 and P-channel FET P1 form the analog switch. During normal operation, these FETs are driven on and off simultaneously according to the control voltages on A_. During a fault condition, both FETs turn off.
Normal Operation
Two comparators continuously compare the voltage on NO_ with V+ and V- supply voltages. When the signal on NO_ ranges between V+ and V-, the multiplexer operates normally, with FETs N1 and P1 turning on and off in response to the control signals on A_ (Figure 1). When the switch state is on, the parallel combination of N1 and P1 forms a low-value resistor between NO_ and COM_ so that signals pass equally well in either direction. When the switch state is off, both NO_ and COM_ are high-impedance inputs.
Fault Conditions
A fault condition occurs when the voltage at any NO_ input exceeds the supply rail. At this point, the output of one of the two fault comparators goes high, effectively turning OFF both FETs N1 and P1. With the two FETs in the OFF position, both the switch input (NO_) and the output (COM_) go into a high-impedance state. They remain high impedance regardless of the state of the control voltages in A_ and EN, until the fault is removed. The input voltage must not exceed the absolute maximum rating at any moment (see the Absolute Maximum Ratings section).
Transient Fault Condition
When a fast rising or falling transient on NO_ exceeds V+ or V-, there is a 100ns delay before the fault protection turns on (see the Typical Operating Characteristics, Fault Response Time). COM_ follows NO_ until the fault protection turns on. This delay is due to the switch on-resistance and circuit capacitance to ground. When the input transient returns to within the supply rails, there is a longer output recovery time (see the Typical Operating Characteristics, Fault Response Times). These values depend on the COM_ output resistance and capacitance. Higher COM_ output resistance and capacitance increase the recovery times. The delays do not depend on the fault amplitude.
NO_ Input Voltage
The maximum allowable input voltage for safe operation depends on whether supplies are on or off, and the load configuration on COM_. If COM_ is referred to a voltage other than ground, but within the supplies, VNO_ can range higher or lower than the supplies, provided the absolute value of |VNO_ - VCOM_| is less than 40V. For example, with V+ = V- = 0, if the load is referred to +10V at COM_, then the NO_ voltage range can be from +50V to -30V. If the supplies are 15V and COM_ is referenced to ground through a load, the maximum NO_ voltage is 36V. If the supplies are off and the COM output is referenced to ground, the maximum NO_ voltage is 40V.
COM and A_
The GND, COM_, and A_ pins are not fault protected. ESD-protection diodes internally connect A_ to both V+ and V-. If a signal on GND, COM_, or A_ exceeds V+ or V- by more than 300mV, excessive current can flow to or from the supplies, possibly damaging the device.
Logic-Level Thresholds
The logic-level thresholds are CMOS and TTL compatible with V+ = +15V and V- = -15V. Logic levels change as V+ increases (see the Typical Operating Characteristics, Logic-Level Threshold Voltage vs. Supply Voltage.)
10
______________________________________________________________________________________
Fault-Protected, Single 8-to-1/ Dual 4-to-1 Multiplexers
Applications Information
Ground
V+ and GND power the internal logic and logic-level translators. The logic-level translators convert the logic-level inputs to V+ and V- to drive the gates of the internal FETs. In this design, there is no galvanic connection inside the MAX4708/MAX4709 between the analog signal paths and GND. ESD-protection diodes connect A_ to V+ and V-.
MAX4708/MAX4709
Chip Information
TRANSISTOR COUNT: 527 SUBSTRATE INTERNALLY CONNECTED TO V+
Package Information
For the latest package outline information, go to www.maxim-ic.com/packages.
Supply Current Reduction
Driving the logic signals rail-to-rail from 0 to +15V or -15V to +15V reduces the current consumption from 370A (typ) to 200A (typ) (see the Electrical Characteristics table, Power Supplies).
Power Supplies
The MAX4708/MAX4709 operate with bipolar supplies between 4.5V and 20V. The V+ and V- supplies need not be symmetrical, but V+ - V- cannot exceed the 44V absolute maximum rating. The MAX4708/MAX4709 operate from single supplies between +9V and +36V when V- is connected to GND.
Pin Configurations/Functional Diagrams (continued)
NORMALLY OPEN SWITCH CONSTRUCTION V+ HIGH FAULT P1 NO_ LOW FAULT COM_
N1
A_
ON
MAX4708 MAX4709 GND
VESD DIODES
Figure 1. Functional Diagram
______________________________________________________________________________________
11
Fault-Protected, Single 8-to-1/ Dual 4-to-1 Multiplexers MAX4708/MAX4709
Test Circuits/Timing Diagrams
V+ A2 A1 A0 NO1 NO2-NO7 +10V
MAX4708
+2.4V 50 EN GND V-
NO8 COM
-10V VOUT CL RL SWITCH OUTPUT VOUT LOGIC INPUT VA_ +3V 50% 0V VNO1
tR < 20ns tF < 20ns
90%
V+ A1 A0 NO1A-NO4A NO1B +10V
0V 90% VNO8
+2.4V
MAX4709
EN GND
NO4B COMB V-
-10V VOUT CL RL
tTRANS
ON
tTRANS
50
Figure 2. Address Transition Time
VEN
EN A0 A1 A2
V+ NO1 NO2-NO8 +10V
MAX4708
COM VOUT RL CL LOGIC INPUT VEN +3V 50% 0V tON(EN) 0V 90% tR < 20ns tF < 20ns tOFF(EN)
50
GND
V-
VEN
EN
V+
NO1B
+10V
A0 A1 50
NO1A-NO4A NO2B-NO4B, COMA
SWITCH OUTPUT VOUT 10%
MAX4709
GND COMB VRL VOUT CL
Figure 3. Enable Switching Time
12
______________________________________________________________________________________
Fault-Protected, Single 8-to-1/ Dual 4-to-1 Multiplexers
Test Circuits/Timing Diagrams (continued)
MAX4708/MAX4709
+2.4V
VEN
EN
V+ NO1-NO8 LOGIC INPUT VA +3V 50% 0V +5V 80% COM GND V1k VOUT 35pF SWITCH OUTPUT VOUT 0V
tR < 20ns tF < 20ns
+10V
A0 A1 VA A2
MAX4708
50
tOPEN
Figure 4. Break-Before-Make Interval
RS NO VEN VS CHANNEL SELECT EN A0 A1 A2 1nF GND VVOUT VOUT IS THE MEASURED VOLTAGE DUE TO CHARGE TRANSFER ERROR VCTE WHEN THE CHANNEL TURNS OFF. VCTE = VOUT X CL VOUT V+ LOGIC INPUT VEN COM VOUT +3V OFF 0V ON OFF
MAX4708
Figure 5. Charge Injection
10nF 10nF
VIN RS = 50
NO1 NO8
V+ R 1k COM VOUT RG = 50 RL 75 VIN
NO1 NO2 NO8 A0 A1 A2
V+
MAX4708
A0 A1 A2 GND EN 10nF OFF-ISOLATION = 20log VOUT VIN V-
MAX4708
COM
VOUT RL 75
GND EN 10nF
V-
CROSSTALK = 20log
VOUT VIN
Figure 6. Off-Isolation
Figure 7. Crosstalk 13
______________________________________________________________________________________
Fault-Protected, Single 8-to-1/ Dual 4-to-1 Multiplexers MAX4708/MAX4709
Test Circuits/Timing Diagrams (continued)
VNO_ 1MHz CAPACITANCE ANALYZER f = 1MHz -15V +25V +15V VCOM_
A2 CHANNEL SELECT A1 A0 GND
V+
NO1 NO8 COM
MAX4708
EN V-
-25V
Figure 8. NO_, COM_ Capacitance
Figure 9. Transient Behavior of Fault Condition
Functional Diagrams/Truth Tables
MAX4708
NO1 NO2 NO3 NO4 NO5 NO6 NO7 NO8 DECODERS/DRIVERS COM V+ VGND
MAX4708
A2 X 0 0 0 0 1 1 1 1 A0 A1 A2 EN A1 X 0 0 1 1 0 0 1 1 A0 X 0 1 0 1 0 1 0 1 EN 0 1 1 1 1 1 1 1 1 ON SWITCH NONE 1 2 3 4 5 6 7 8
LOGIC 0 VAL +0.8V, LOGIC 1 VAH +2.4V
MAX4709
NO1A NO2A NO3A NO4A NO1B NO2B NO3B NO4B
V+
V-
GND
COMA A1 X COMB 0 0 1 1 DECODERS/DRIVERS A0 X 0 1 0 1
MAX4709
EN 0 1 1 1 1 ON SWITCH NONE 1 2 3 4
LOGIC 0 VAL +0.8V, LOGIC 1 VAH +2.4V A0 A1 EN
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.
14 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2002 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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