_______________General Description
The MAX354/MAX355 fault-protected multiplexers
(muxes) use a series N-channel, P-channel, N-channel
structure that protects the devices from overvoltage up
to 40V beyond the supply rails during power-up, power-
down, and fault conditions. The MAX354/MAX355 also
protect sensitive circuit components against voltages
near or beyond the normal supplies.
The MAX354 single 8-channel mux and the MAX355
dual 4-channel mux protect analog signals while oper-
ating from a single 4.5V to 36V supply or ±4.5V to ±18V
dual supplies. These muxes have 350Ωon-resistance
and can be used for demultiplexing as well as multi-
plexing. Input leakage current is less than 0.5nA at
+25°C and less than 5nA at +85°C.
All digital inputs have 0.8V and 2.4V logic thresholds,
ensuring both TTL and CMOS logic compatibility with-
out pull-up resistors. Break-before-make operation is
guaranteed and power consumption is less than
1.5mW.
________________________Applications
Data-Acquisition Systems
Industrial and Process Control
Avionics
ATE Equipment
Signal Routing
Redundant/Backup Systems
____________________________Features
♦350ΩMax On-Resistance
♦Improved 2nd Source for MAX358/MAX359 and
DG458/DG459
♦Pin Compatible with ADG508F/ADG509F
♦All Switches Off with Supplies Off
♦On Switch Turns Off with Overvoltage
♦Output Clamps at 1.5V Below Supply Rails
♦0.5nA Max Input Leakage at +25°C (5nA at +85°C)
♦No Power-Up Sequencing Required
♦TTL and CMOS-Logic Compatibility
______________Ordering Information
* Dice are tested at TA = +25°C only.
** Contact factory for availability.
________________________________________________________________
Maxim Integrated Products
1
16
15
14
13
12
11
10
9
1
2
3
4
5
6
7
8
A1
A2
GND
V+
NO1
V-
EN
A0
TOP VIEW
MAX354
NO5
NO6
NO7
NO8
COM
NO4
NO3
NO2
DIP/SO
LOGIC
16
15
14
13
12
11
10
9
1
2
3
4
5
6
7
8
A1
GND
V+
NO1B
NO1A
V-
EN
A0
MAX355
NO2B
NO3B
NO4B
COMB
COMA
NO4A
NO3A
NO2A
DIP/SO
LOGIC
__________________________________________________________Pin Configurations
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800
PART
MAX354CPE
MAX354CWE
MAX354C/D 0°C to +70°C
0°C to +70°C
0°C to +70°C
TEMP. RANGE PIN-PACKAGE
16 Plastic DIP
16 Wide SO
Dice*
MAX354EPE
MAX354EWE -40°C to +85°C
-40°C to +85°C 16 Plastic DIP
16 Wide SO
MAX354MJE -55°C to +125°C 16 CERDIP**
19-0389; Rev. 2; 9/96
MAX355CPE
MAX355CWE
MAX355C/D 0°C to +70°C
0°C to +70°C
0°C to +70°C 16 Plastic DIP
16 Wide SO
Dice*
MAX355EPE
MAX355EWE -40°C to +85°C
-40°C to +85°C 16 Plastic DIP
16 Wide SO
MAX355MJE -55°C to +125°C 16 CERDIP**
MAX354/MAX355
Fault-Protected Analog Multiplexers
MAX354/MAX355
Fault-Protected Analog Multiplexers
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V+ = +15V, V- = -15V, GND = 0V, VAH = VENH = 2.4V, VAL = VENL = 0.8V, TA= TMIN to TMAX, unless otherwise noted.)
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.
(Voltages referenced to GND, unless otherwise noted.)
V+...........................................................................-0.3V to +44V
V-............................................................................+0.3V to -44V
V+ to V-...................................................................-0.3V to +44V
Digital Inputs.........................................(V+ + 0.3V) to (V- - 0.3V)
Input Overvoltage with Mux Power On
V+ = +15V ....................................................................... +25V
V- = -15V............................................................................-25V
Input Overvoltage with Mux Power Off
V+ = 0V.............................................................................+40V
V- = 0V...............................................................................-40V
Continuous Current into Any Terminal .............................±30mA
Peak Current into Any Terminal........................................±50mA
Continuous Power Dissipation (TA= +70°C)
Plastic DIP (derate 10.53mW/°C above +70°C) ...........842mW
Wide SO (derate 9.52mW/°C above +70°C)................ 762mW
CERDIP (derate 10.00mW/°C above +70°C) ...............800mW
Operating Temperature Ranges
MAX35_C_ _ ........................................................0°C to +70°C
MAX35_E_ _......................................................-40°C to +85°C
MAX35_M_ _...................................................-55°C to +125°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10sec)............................ +300°C
VCOM = ±10V,
VNO = ±10V,
VEN = 0V
VCOM = ±10V,
VNO = ±10V,
VEN = 0V
CONDITIONS
-50 50
ICOM(OFF)
COM-Off Leakage Current
(Note 4)
-15 15
-0.5 0.02 0.5
-100 100
-25 25
nA
-0.5 0.02 0.5
V(V+ - 40) (V- + 40)
VCOM, VNO
Analog Signal Range
500
RON
On-Resistance
(Note 2) 450 Ω
285 350
UNITSMIN TYP MAXSYMBOLPARAMETER
TA= TMIN
to TMAX
TA= TMIN
to TMAX
TA= TMIN
to TMAX
MAX355
INO = 1.0mA, VCOM = ±10V
MAX354
(Note 1)
M
C, E
M
C, E
TA= +25°C M
TA= +25°C
C, E
TA= +25°C
VCOM = ±10V,
VNO = ±10V,
sequence each
switch on
-100 100
ICOM(ON)
COM-On Leakage Current
(Note 4)
-15 15
-0.5 0.02 0.5
-200 200
-30 30
nA
-0.5 0.02 0.5
TA= TMIN
to TMAX
TA= TMIN
to TMAX
MAX355
MAX354
M
C, E
TA= +25°C M
C, E
TA= +25°C
-12 12
Fault-Free Analog
Signal Range V+ = +15V, V- = -15V (Note 1)
Ω
712
-50 50
INO(OFF)
NO-Off Leakage Current
(Note 4) -5.0 5.0 nA
-0.5 0.01 0.5
15
∆RON
On-Resistance Matching
Between Channels
TA= TMIN
to TMAX
VCOM = ±10V,
VNO = ±10V,
VEN = 0V
INO = 1.0mA, VCOM = ±10V
(Note 3) TA= +25°C
M
C, E
TA= +25°C
TA= TMIN to TMAX
SWITCH
±
±
±
V
pF
VEN = VA= 0V
MAX354/MAX355
Fault-Protected Analog Multiplexers
_______________________________________________________________________________________ 3
CONDITIONS
pF1.6CNO(OFF)
NO-Off Capacitance
VCT
Crosstalk Between Channels dB92
ns50 100tOPEN
Break-Before-Make Interval
ns
400
tON(EN)
Enable Turn-On Time 160 250
nA-5 0.01 5
Output Leakage Current
(with Overvoltage)
ns
180 250
tTRANS
Transition Time
V±4.5 ±18Power-Supply Range
µA
-300 300
I+Positive Supply Current
µA
-1 1
I-Negative Supply Current
UNITSMIN TYP MAXSYMBOLPARAMETER
f = 1MHz, VEN = VD= 0V
VEN = 2.4V, f = 100kHz,
VGEN = 1Vp-p, RL= 1kΩ,
Figure 6
Figure1
Figure 3
Figure 2
VD= 0V,
analog overvoltage = ±33V
TA= +25°C
TA= +25°C
TA= +25°C
TA= +25°C
TA= +25°C
TA= +25°C
TA= TMIN to TMAX
TA= +25°C
ELECTRICAL CHARACTERISTICS (continued)
(V+ = +15V, V- = -15V, GND = 0V, VAH = VENH = 2.4V, VAL = VENL = 0.8V, TA= TMIN to TMAX, unless otherwise noted.)
TA= +25°C
µAVA= VEN = 0.8V
VA= VEN = 2.4V µA
-1 1
IA_H, IENH
Input Current with
Input Voltage High
-1 1
IA_L, IENL
Input Current with
Input Voltage Low
VEN = VA= 5V
ns
300
tOFF(EN)
Enable Turn-Off Time 80 200
Figure 2 TA= TMIN to TMAX
TA= +25°C
VTA= TMIN to TMAX
TA= TMIN to TMAX V2.4VA_H, VENH
Logic High Input Voltage 0.8VA_L, VENL
Logic Low Input Voltage
TA= TMIN to TMAX µA-2 2
TA= +25°C
TA= TMIN to TMAX µA
-2 2
-0.1 0.001 0.1
Input Leakage Current
(with Overvoltage) VIN = ±25V, VO= ±10V
TA= +25°C
TA= TMIN to TMAX µA
-2 2
-0.1 0.001 0.1
Input Leakage Current
(with Power Supplies Off) VIN = ±25V, VEN = VO= 0V,
VA0 = VA1 = VA2 = 0V or 5V
TA= +25°C
TA= TMIN to TMAX
TA= +25°C
TA= TMIN to TMAX
-5 5
-5 5
TA= TMIN to TMAX -500 500
TA= TMIN to TMAX -100 100
TA= TMIN to TMAX 400
pC80VCTE
Charge Injection CL= 10nF, VS= 0V, RS= 0Ω,
Figure 4 TA= +25°C
dB100VISO
Off Isolation VEN = 0V, R L= 1k Ω, f = 100kHz,
Figure 5 TA= +25°C
pF2.5CIN
Logic Input Capacitance f = 1MHz, Figure 7 TA= +25°C
FAULT
SUPPLY
DYNAMIC
DIGITAL LOGIC INPUT
MAX354/MAX355
Fault-Protected Analog Multiplexers
4 _______________________________________________________________________________________
__________________________________________Typical Operating Characteristics
(TA = +25°C, unless otherwise noted.)
100
10
0.0001-15 15
ON-RESISTANCE vs. ANALOG VOLTAGE
1
MAX354/5-1a
ANALOG VOLTAGE (V)
RON (MΩ)
0
0.01
0.001
-10 -5 10
0.1
5
V+ = +5V
V- = -5V
V+ = +15V
V- = -15V
2000
1600
1800
0-15 15
ON-RESISTANCE vs. ANALOG VOLTAGE
800
1000
1200
1400
MAX354/5-1b
ANALOG VOLTAGE (V)
RON (Ω)
0
400
200
-10 -5 10
600
5
V+ = +5V
V- = -5V
V+ = +15V
V- = -15V
V+ = +10V
V- = -10V
700
600
100
ON-RESISTANCE vs.
VCOM AND TEMPERATURE
500
MAX354/5-2
VCOM (V)
RON (Ω)
0
300
200
-10 -5 10
400
5
A: +125°C
B: +85°C
C: +70°C
D: +25°C
V+ = +15V
V- = -15V
A
C
D
B
100
0.01 -75 75 100 125
OFF LEAKAGE vs. TEMPERATURE
10
MAX354-3
TEMPERATURE (°C)
OFF LEAKAGE (nA)
0
0.1
-50 -25 50
1
25
V+ = +15V
V- = -15V
VNO_ = ±10V
VCOM_ = 10V ICOM(OFF)
INO(OFF)
100
0.01 -75 75 100 125
ON LEAKAGE vs. TEMPERATURE
10
MAX354-4
TEMPERATURE (°C)
ON LEAKAGE (nA)
0
0.1
-50 -25 50
1
25
V+ = +15V
V- = -15V
VCOM_ = ±10V
200
-200 -10 5 10
CHARGE INJECTION vs. VCOM
100
150
MAX354-5
VCOM (V)
Qj (pC)
-100
-150
-5
50
0
-50
0
V+ = +15V
V- = -15V
Note 1: When the analog signal exceeds +13.5V or -13.5V, the blocking action of Maxim
’
s gate structure goes into operation. Only
leakage currents flow, and the channel on-resistance rises to infinity (see
Typical Operating Characteristics
).
Note 2: Electrical characteristics such as on-resistance will change when power supplies other than ±15V are used.
Note 3: ∆RON = RON(MAX) - RON(MIN)
Note 4: Leakage parameters are 100% tested at maximum rated hot operating temperature, and guaranteed by correlation at +25°C.
Note 5: Guaranteed by design.
ELECTRICAL CHARACTERISTICS (continued)
(V+ = +15V, V- = -15V, GND = 0V, VAH = VENH = 2.4V, VAL = VENL = 0.8V, TA= TMIN to TMAX, unless otherwise noted.)
f = 1MHz, Figure 7,
VEN = VD= 0V
f = 1MHz, Figure 7,
VEN = VD= 0V
CONDITIONS
14
CCOM(ON)
COM-On Capacitance pF
28
5
CCOM(OFF)
COM-Off Capacitance pF
11
0.1% 2.5
tSETT
Setting Time (Note 5)
UNITSMIN TYP MAXSYMBOLPARAMETER
MAX355
MAX354
MAX355
MAX354
µs
1
TA= +25°C
0.01%
TA= +25°C
TA= +25°C
DYNAMIC (cont’d)
MAX354/MAX355
Fault-Protected Analog Multiplexers
_______________________________________________________________________________________ 5
____________________________Typical Operating Characteristics (continued)
(TA = +25°C, unless otherwise noted.)
______________________________________________________________Pin Description
1000
0.1 -75 75 100 125
SUPPLY CURRENT vs. TEMPERATURE
100
MAX354-6
TEMPERATURE (°C)
I+, I- (µA)
0
1
-50 -25 50
10
25
V+ = +15V
V- = -15V
VEN = +5V
I+ (VA_ = 0V)
I-
I+ (VA_ = 5V)
10m
10p
1n
-70 -10 10 30 50 70
FAULT CURRENT vs. FAULT VOLTAGE
1m
FAULT VOLTAGE (V)
FAULT CURRENT (A)
100p
-50
100µ
10µ
1µ
100m
10n
-30
V+ = V- = 0V
V+ = +15V
V- = -15V
GroundGND1514
Positive Supply Voltage InputV+1413
Analog Inputs—bidirectional “B” switchNO4B–NO1B10–13—
Analog Inputs—bidirectionalNO8–NO5—9–12
Analog Outputs—bidirectionalCOMA, COMB8, 9—
Analog Output—bidirectionalCOM—8
Analog Inputs—bidirectional “A” switchNO1A–NO4A4–7—
Analog Inputs—bidirectionalNO1–NO4—4–7
Negative Supply Voltage Input. Connect to GND for single-supply operation.V-33
Enable Logic Input. See truth tables.EN22
Address Logic InputsA0, A1
—
—
Address Logic InputsA0, A2, A11, 15, 16
FUNCTIONNAME
MAX355MAX354
PIN
1, 16
Note: Analog inputs and outputs are electrically identical and completely interchangeable.
MAX354/MAX355
Fault-Protected Analog Multiplexers
6 _______________________________________________________________________________________
50%
tOFF(EN)
tR < 20ns
tF < 20ns
+3V
0V
0V
LOGIC
INPUT
VEN
SWITCH
OUTPUT
VOUT
+15V
VOUT
-15V
GND
V+
A1
V-
A0
A2
EN NO1
NO2–NO8
COM
+10V
50Ω
MAX354
1k 35pF
90%
10%
tON(EN)
+15V
VOUT
-15V
GND
V+
A1
V-
A0
EN NO1B
NO1A–NO4A
NO2B–NO4B,
COMA
COMB
+10V
50Ω
MAX355
1k 35pF
VEN
VEN
Figure 2. Enable Switching Time
______________________________________________Test Circuits/Timing Diagrams
50%
tTRANS
tR < 20ns
tF < 20ns
VOUT
+3V
0V
VNO1
0V
VNO8
LOGIC
INPUT
VEN
SWITCH
OUTPUT
+15V
VOUT
-15V
GND
V+
A1
V-
A2
A0
EN
NO1
NO2-NO7
NO8
COM
+10V
-10V
50Ω
MAX354
300Ω35pF
+15V
VOUT
-15V
GND
V+
A0
V-
A1
EN
NO1B
NO1A-NO4A
NO4B
COMB
+10V
50Ω
MAX355
300Ω35pF
90%
90%
tTRANS
ON
-10V
VEN
VEN
Figure 1. Transition Time
MAX354/MAX355
Fault-Protected Analog Multiplexers
_______________________________________________________________________________________ 7
50%
tOPEN
tR < 20ns
tF < 20ns
+5V
+3V
0V
LOGIC
INPUT
VA
SWITCH
OUTPUT
VOUT
+15V
VOUT
-15V
GND
V+
A0
V-
A1
A2
EN
NO1–NO8
COM
+10V
50Ω
MAX354
300Ω35pF
80%
+2.4V
0V
VA
VEN
_________________________________Test Circuits/Timing Diagrams (continued)
Figure 3. Break-Before-Make Interval
∆VOUT
+3V
0V
LOGIC
INPUT
VEN
+15V
VOUT
-15V
GND
V+
A1
V-
A0
A2
EN
COM
MAX354
CL = 1000nF VOUT
NO
CHANNEL
SELECT
RS
VS
ONOFF OFF
∆VOUT IS THE MEASURED VOLTAGE DUE TO CHARGE TRANSFER
ERROR VCTE WHEN THE CHANNEL TURNS OFF.
VCTE = ∆VOUT x CL
VEN
Figure 4. Charge Injection
MAX354/MAX355
Fault-Protected Analog Multiplexers
8 _______________________________________________________________________________________
_________________________________Test Circuits/Timing Diagrams (continued)
+15V
VOUT
-15V
GND
V+
A1
V-
A0
A2
NO8
COM
MAX354
NO1
RS = 50Ω
VIN
EN
10nF
RL
1k
OFF ISOLATION = 20log VOUT
VIN
10nF
+15V
VOUT
-15V
GND
V+
A1
V-
A0
A2
NO8 COM
MAX354
NO2
RG = 50Ω
VIN
EN
10nF
RL
1k
CROSSTALK = 20log VOUT
VIN
10nF
NO1
R = 1kΩ
+15V
-15V
GND
V+
A2
V-
A1
A0
NO8
MAX354
CHANNEL
SELECT
NO1
COM
EN
1MHz
CAPACITANCE
ANALYZER
f = 1MHz
Figure 5. Off Isolation Figure 6. Crosstalk
Figure 7. NO/COM Capacitance
_______________Detailed Description
Fault-Protection Circuitry
Maxim’s MAX354/MAX355 are fully fault protected for
continuous input voltages up to ±40V, whether or not
the V+ and V- power supplies are present. These
devices use a “series FET” protection scheme that not
only protects the multiplexer output from overvoltage,
but also limits the input current to sub-microamp levels.
When signal voltages exceed or are within approxi-
mately 1.5V of the supply rails, on-resistance increas-
es. This greater on-resistance limits fault currents and
output voltage, protecting sensitive circuits and com-
ponents. The protected output clamps at approximately
1.5V below the supply rails and maintains the correct
polarity. There are no glitches or polarity reversals
going into or coming out of a fault condition.
Figures 8 and 9 show how the series FET circuit protects
against overvoltage conditions. When power is off, the
gates of all three FETs are at ground. With a -25V input,
N-channel FET Q1 is turned on by the +25V gate-to-
source voltage. The P-channel device (Q2), however,
has +25V VGS and is turned off, thereby preventing the
input signal from reaching the output. If the input volt-
age is +25V, Q1 has a negative VGS, which turns it off.
Similarly, only sub-microamp leakage currents can flow
from the output back to the input, since any voltage will
turn off either Q1 or Q2.
Figure 10 shows the condition of an off channel with V+
and V- present. As with Figures 8 and 9, either an N-
channel or a P-channel device will be off for any input
voltage from -40V to +40V. The leakage current with
negative overvoltages will immediately drop to a few
nanoamps at +25°C. For positive overvoltages, that
fault current will initially be 10µA or 20µA, decaying
over a few seconds to the nanoamp level. The time
constant of this decay is caused by the discharge of
stored charge from internal nodes and does not com-
promise the fault-protection scheme.
Figure 11 shows the condition of the on channel with
V+ and V- present. With input voltages less than ±10V,
all three FETs are on and the input signal appears at
the output. If the input voltage exceeds V+ minus the
N-channel threshold voltage (VTN), the N-channel FET
will turn off. For voltages more negative than V- minus
the P-channel threshold (VTP), the P-channel device will
turn off. Since VTN is typically 1.5V and VTP is typically
3V, the multiplexer’s output swing is limited to about -12V
to +13.5V with ±15V supplies.
Switching Characteristics
and Charge Injection
Table 1 shows typical charge injection levels versus
power-supply voltages and analog input voltage. The
charge injection that occurs during switching creates a
voltage transient whose magnitude is inversely propor-
tional to the capacitance on the multiplexer output.
MAX354/MAX355
Fault-Protected Analog Multiplexers
_______________________________________________________________________________________ 9
G
D
Q1
S-25V
N-CHANNEL MOSFET
IS TURNED ON
BECAUSE VGS = +25V
-25V
OVERVOLTAGE
P-CHANNEL
MOSFET IS OFF
G
D
Q2
S
G
D
Q3
S
Figure 8. -25V Overvoltage with Multiplexer Power Off
+15V-15V -15V
Q1
N-CHANNEL MOSFET
IS TURNED ON
BECAUSE VGS = +10V
-25V
OVERVOLTAGE
P-CHANNEL
MOSFET IS OFF
N-CHANNEL
MOSFET IS OFF
+15V FROM
DRIVERS
-15V FROM
DRIVERS
+25V FORCED
ON COMMON
OUTPUT LINE BY
EXTERNAL CIRCUITRY
Q2 Q3
Figure 10. -25V Overvoltage on an Off Channel with
Multiplexer Power Supply On
G
D
Q1
S
N-CHANNEL MOSFET
IS TURNED OFF
BECAUSE VGS = -25V
+25V
OVERVOLTAGE
G
D
Q2
S
G
D
Q3
S
Figure 9. +25V Overvoltage with Multiplexer Power Off
+15V-15V -15V
Q1
N-CHANNEL MOSFET
IS TURNED OFF
BECAUSE VGS = -10V
+25V
OVERVOLTAGE
13.5V
VTN = 1.5V N-CHANNEL
MOSFET IS ON
-15V FROM
DRIVERS
+15V FROM
DRIVERS
13.5V
OUTPUT
Q2 Q3
Figure 11. +25V Overvoltage Input to the On Channel
Table 1. MAX354 Charge Injection
Test Conditions: CL, = 1000pF on mux output; the tabulated
analog input level is applied to channel 1; channels 2–8 inputs
are open circuited. EN = +5V, VA1 = VA2 = 0V, VOis toggled at
a 2kHz rate between 0V and 3V. +100pC of charge creates a
+100mV step when injected into a 1000pF load capacitance.
Supply Voltage Analog Input Level Injected Charge
±5V +2V
0V
-2V
52pC
35pC
16pC
±10V +5V
0V
-5V
105pC
65pC
25pC
±15V +10V
0V
-10V
180pC
80pC
15pC
MAX354/MAX355
The channel-to-channel switching time is typically
180ns, with about 100ns of break-before-make delay.
This 100ns break-before-make delay prevents the
input-to-input short that would occur if two input chan-
nels were simultaneously connected to the output. In a
typical data acquisition system, the dominant delay is
not the switching time of the multiplexer, but is the set-
tling time of the amplifiers and S/H. Another limiting fac-
tor is the RC time constant of the multiplexer RON plus
the signal source impedance multiplied by the load
capacitance on the output of the multiplexer. Even with
low signal source impedances, 100pF of capacitance
on the multiplexer output will approximately double the
settling time to 0.01% accuracy.
Operation with Supply Voltages
Other than ±15V
The main effect of supply voltages other than ±15V is
the reduction in output signal range. The MAX354 limits
the output voltage to about 1.5V below V+ and about
3V above V-. In other words, the output swing is limited
to +3.5V to -2V when operating from ±5V. The
Typical
Operating Characteristics
show RON for +15V and ±5V
power supplies. Maxim tests and guarantees the
MAX354/MAX355 for operation from ±4.5V to ±18V
supplies. The switching delays are increased by about
a factor of 2 at ±5V, but break-before-make action is
preserved.
The MAX354/MAX355 can operate with a single +4.5V
to +30V supply, as well as asymmetrical power sup-
plies such as +15V and -5V. The digital threshold
remains approximately 1.6V above the GND pin, and
the analog characteristics, such as RON, are deter-
mined by the total voltage difference between V+ and
V-. Connect V- to 0V when operating with a +4.5V to
+30V single supply.
The MAX354 digital threshold is relatively independent
of the power-supply voltages, going from 1.6V typical
when V+ is 15V to 1.5V typical when V+ is 5V. This
means that the MAX354/MAX355 operate with standard
TTL-logic levels, even with ±5V power supplies. In all
cases, the threshold of the enable (EN) pin is the same
as the other logic inputs.
Digital Interface Levels
The typical digital threshold of both the address lines
and the enable pin is 1.6V, with a temperature coeffi-
cient of about -3mV/°C. This ensures compatibility with
0.8V to 2.4V TTL-logic swings over the entire tempera-
ture range. The digital threshold is relatively indepen-
dent of the supply voltages, moving from 1.6V typical to
1.5V typical as the power supplies are reduced from
±15V to ±5V. In all cases, the digital threshold is refer-
enced to the GND pin.
The digital inputs can also be driven with CMOS-logic
levels swinging from either V+ to V- or from V+ to
ground. The digital input current is just a few nanoamps
of leakage at all input voltage levels, with a guaranteed
maximum of 1µA.
Operation as a Demultiplexer
The MAX354/MAX355 function as demultiplexers where
the input is applied to the output pin, and the input pins
are used as outputs. The MAX354/MAX355 provide
both break-before-make action and full fault protection
when operated as demultiplexers, unlike earlier genera-
tions of fault-protected muxes.
Channel-to-Channel Crosstalk,
Off-Isolation, and Digital Feedthrough
At DC and low frequencies the channel-to-channel
crosstalk is caused by variations in output leakage cur-
rents as the off-channel input voltages are varied. The
MAX354 output leakage varies only a few picoamps as
all seven off inputs are toggled from -10V to +10V. The
output voltage change depends on the impedance
level at the MAX354 output, which is RON plus the input
signal source resistance in most cases, since the load
driven by the MAX354 is usually high impedance. For a
signal source impedance of 10kΩor lower, the DC
crosstalk exceeds 120dB.
Tables 2a and 2b show typical AC crosstalk and off-
isolation performance. Digital feedthrough is masked
by the analog charge injection when the output is
enabled. When the output is disabled, the digital
feedthrough is virtually unmeasureable, since the digi-
tal pins are physically isolated from the analog section
by the GND and V- pins. The ground plane formed by
these lines is continued onto the MAX354/MAX355 die
to provide over 100dB isolation between the digital and
analog sections.
Fault-Protected Analog Multiplexers
10 ______________________________________________________________________________________
MAX354/MAX355
Fault-Protected Analog Multiplexers
______________________________________________________________________________________ 11
DECODERS / DRIVERS
COM
NO1
NO2
NO3
NO4
NO5
NO6
NO7
NO8
A0 A1 A2 EN
V+ V- GND
MAX354
A0A1A2 EN ON SWITCH
X
0
0
0
0
1
1
1
1
X
0
0
1
1
0
0
1
1
X
0
1
0
1
0
1
0
1
0
1
1
1
1
1
1
1
1
NONE
1
2
3
4
5
6
7
8
LOGIC "O" VAL ≤ +0.8V, LOGIC "1" VAH ≥ +2.4V
MAX354
__________________________________________Functional Diagrams/Truth Tables
DECODERS / DRIVERS
COMA
NO1A
NO2A
NO3A
NO4A
A0 A1 EN
V+ V- GND
MAX355
COMB
NO1B
NO2B
NO3B
NO4B
A0A1 EN ON SWITCH
X
0
0
1
1
X
0
1
0
1
0
1
1
1
1
NONE
1
2
3
4
LOGIC "O" VAL ≤ +0.8V, LOGIC "1" VAH ≥ +2.4V
MAX355
Table 2a. Typical Off-Isolation Rejection
Ratio Table 2b. Typical Crosstalk Rejection Ratio
Frequency 100kHz 1MHz
One Channel Driven 100dB 80dB
Frequency 100kHz 1MHz
RL= 1.5kΩ92dB 72dB
RL= 10kΩ76dB 56dB
Test Conditions: Specified RLconnected from OUT to ground,
EN = +5V, A0= A1= A2= +5V (Channel 1 selected). 20Vp-p
at the tabulated frequency is applied to Channel 2. All other
channels are open circuited. Similar crosstalk rejection can be
observed between any two channels.
Test Conditions: VIN = 20Vp-p at the tabulated frequency,
RL= 1.5kΩbetween OUT and ground, EN = 0V.
20Vp-p
VISO = 20log —————
VOUT (p-p)
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
12
__________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 (408) 737-7600
© 1996 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
MAX354/MAX355
Fault-Protected Analog Multiplexers
__________________________________________________________Chip Topographies
V+
N03A
EN
N04A
0.130"
(3.30mm)
0.115"
(2.92mm)
COMA COMB N04B
N.C.
N01B
N02B
N03B
A0 A1 GND
N02A
N01A
V-
V+
N03
EN
0.130"
(3.30mm)
0.115"
(2.92mm)
N05
N06
N.C.
A0 A1 A2 GND
N02
N01
V-
N04 COM N08 N07
TRANSISTOR COUNT: 256
SUBSTRATE CONNECTED TO V+
MAX355
MAX354