MAXIM MAX14778 Technical data
EVALUATION KIT AVAILABLE
19-5929; Rev 1; 6/12
MAX14778
Dual ±25V Above- and Below-the-Rails
4:1 Analog Multiplexer
General Description
The MAX14778 dual 4:1 analog multiplexer supports
analog signals up to Q25V with a single 3.0 to 5.5V
supply. Each multiplexer has separate control inputs to
allow independent switching, making the device ideal for
multiplexing different communications signals with the
same connector pins. Extended ESD protection of Q6kV
(Human Body Model) enable direct interfacing to cables
and connectors.
The MAX14778 features a low 1.5I (max) on-resistance
and 3mI (typ) flatness to maximize signal integrity over
the entire common-mode voltage range. Each multiplexer can carry up to 300mA of continuous current through
the multiplexer in either direction.
The MAX14778 supports switching of full-speed USB 1.1
signals (12Mbps) and RS-485 data rates of up to 20Mbps.
The MAX14778 is available in a 20-pin (5mm x 5mm)
TQFN package and is specified over the -40NC to +85NC
extended temperature range.
Applications
RS-485/RS-232/USB 1.1 Multiplexing
POS Peripherals
Handheld Industrial Devices
Communication Systems
Audio/Data Multiplexing
Connector Sharing
Gaming Machines
Features
S ±25V Signal Range
S Single 3.0V to 5.5V Supply
S Two Independent Multiplexers
S 1.5I RON (max)
S 3mI RON Flatness (typ)
S 300mA Maximum Current Through Multiplexer
S 78pF Input Capacitance
S 75MHz Large-Signal Bandwidth
S Break-Before-Make Operation
S Extended ESD Protection on A� and B� Pins
Q6kV Human Body Model (HBM)
Ordering Information appears at end of data sheet.
For related parts and recommended products to use with this part,
refer to www.maxim-ic.com/MAX14778.related.
Functional Diagram
SA0ENA
SA1 V
CONTROL A
A0
A1
A2
DD
BIAS
GENERATION
MAX14778
V
P
V
N
ACOM
A3
B0
B1
B2
B3
CONTROL B
SB0ENB SB1
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GND
BCOM
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
MAX14778
Dual ±25V Above- and Below-the-Rails
4:1 Analog Multiplexer
ABSOLUTE MAXIMUM RATINGS
(All voltages referenced to GND.)
VDD .......................................................................... -0.3V to +6V
VP ........................... -0.3V to the lesser of +52V and (VN + 70V)
VN ................ The lesser of (VDD - 40V) and (VP - 70V) to +0.3V
VP to VN ................................................................. -0.3V to +70V
ENA, ENB, SA_, SB_ ................................ -0.3V to (VDD + 0.3V)
A_, ACOM, B_,
BCOM .. (VN - 0.3V) to the lesser of (VP + 0.3V) and (VN + 52V)
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.
PACKAGE THERMAL CHARACTERISTICS (Note 1)
TQFN
Junction-to-Ambient Thermal Resistance (BJA) ..........30NC/W
Junction-to-Case Thermal Resistance (BJC) .................2NC/W
Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-
layer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial.
Continuous Current Through Switch ............................. ±500mA
Continuous Power Dissipation (TA = +70NC)
TQFN (derate 33.3mW/NC above +70NC)...............2666.7mW
Operating Temperature Range .......................... -40NC to +85NC
Junction Temperature .....................................................+150NC
Storage Temperature Range ............................ -65NC to +150NC
Lead Temperature (soldering, 10s) ...............................+300NC
Soldering Temperature (reflow) ......................................+260NC
ELECTRICAL CHARACTERISTICS
(VDD = 3.0V to 5.5V, T
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
DC CHARACTERISTICS
Supply Voltage Range V
Supply Current I
Charge-Pump Threshold V
Analog Signal Range V
Continuous Current
Through Switch
On-Resistance R
On-Resistance Flatness R
A_, B_ Off-Leakage
Current
ACOM, BCOM
Off-Leakage Current
A_, B_ On-Leakage
Current
= -40NC to +85NC, unless otherwise noted. Typical values are at VDD = 5V, T
A
DD
DD
DDTH
IN
I
COM
ON
FLAT(ON)
I
A(OFF)
I
B(OFF)
I
ACOM(OFF)
I
BCOM(OFF)
I
A(ON)
I
B(ON)
ENA = ENB = high
V
= V
ENA
(Note 3) 4.64 V
Figure 1, switch open or closed -25 +25 V
Figure 1, I
Figure 1, -25V P VIN P +25V,
I
= Q300mA
COM
,
Figure 2, VIN = 25V, V
,
Figure 2, V
,
Figure 2, VIN = Q25V, ACOM or BCOM
is unconnected
= VDD/2
ENB
= Q300mA, VIN = Q25V
COM
= 15V, VIN = 0V -1 +1
OUT
VDD P V
VDD > V
VDD P V
VDD > V
OUT
DDTH
DDTH
DDTH
DDTH
= 0V -200 +200 nA
3.0 5.5 V
-300 +300 mA
-1 +1
= +25NC.) (Note 2)
A
4.27 10
2.54 6
4.31 10
2.59 6
0.84 1.5 Ω
3 mΩ
mA
FA
FA
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MAX14778
Dual ±25V Above- and Below-the-Rails
4:1 Analog Multiplexer
ELECTRICAL CHARACTERISTICS (continued)
(VDD = 3.0V to 5.5V, T
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
LOGIC INPUTS (ENA, ENB, SA�, SB�)
Input Logic-Low Voltage V
Input Logic-High Voltage V
AC CHARACTERISTICS
Power-Up Time t
Enable Turn-On Time t
Enable Turn-Off Time t
Break-Before-Make
Interval
Charge Injection Q Figure 5, VA_ = 0V, CL = 1nF 1720 pC
Off-Isolation V
Crosstalk V
= -40NC to +85NC, unless otherwise noted. Typical values are at VDD = 5V, T
A
VDD = 5.5V 0.8
VDD = 4.5V 0.8
VDD = 3.6V 0.7
VDD = 3.0V 0.7
VDD = 5.5V 2.1
VDD = 4.5V 2.0
VDD = 3.6V 1.9
VDD = 3.0V 1.7
Figure 3, VIN = Q10V, RL = 10kI,
CL = 15pF
Figure 3, VIN = Q10V, RL = 10kI,
CL = 15pF
Figure 4, VIN = Q10V, RL = 10kI,
CL = 15pF
Figure 6, VA_ = 1V
RL = 50I, CL = 15pF
Figure 6, f = 100kHz, RS = RL = 50I
, f = 100kHz,
RMS
POR
ON
OFF
t
BBM
ISO
IL
IH
CT
= +25NC.) (Note 2)
A
404 ms
2 ms
1.5 ms
840
-80 dB
-103 dB
V
V
Fs
-3dB Bandwidth BW
Total Harmonic Distortion
Plus Noise
Input Capacitance C
THERMAL PROTECTION
Thermal-Shutdown
Threshold
Thermal-Shutdown
Hysteresis
ESD PROTECTION
A_, B_ Pins (Note 4) Human Body Model
All Other Pins Human Body Model
Note 2: All units are production tested at TA = +25NC. Specifications over temperature are guaranteed by design.
Note 3: When VDD is higher than the charge-pump threshold, the internal 5V regulated charge pump is turned off and the input to
the high-voltage charge pumps is provided by VDD.
Note 4: The MAX14778 requires a 100nF capacitor on both VP and VN to GND to guarantee full ESD protection. See the
Applications Information section for details on ESD test conditions.
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THD+N
IN
T
SHUT
T
HYST
Figure 6, RS = 50I, RL = 50I
RS = RL = 1kI, f = 20Hz to 20kHz
A_, B_ pins 78 pF
75 MHz
0.003 %
145
25
Q6
Q2
NC
NC
kV
kV
MAX14778
Dual ±25V Above- and Below-the-Rails
4:1 Analog Multiplexer
Test Circuits/Timing Diagrams
V
+5V
1µF
V
DD
MAX14778
A_
B_
ACOM
BCOM
Figure 1. On-Resistance Measurement
I
A(OFF)
I
B(OFF)
A
V
IN
MAX14778
A_
B_
+5V
V
GND
V
IN
1µF
DD
I
ACOM(OFF)
I
BCOM(OFF)
ACOM
BCOM
A
GND
V
OUT
I
COM
+5V
1µF
V
DD
I
A(ON)
I
B(ON)
A
V
IN
MAX14778
A_
B_
ACOM
BCOM
GND
Figure 2. Leakage Current Measurement
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MAX14778
Dual ±25V Above- and Below-the-Rails
4:1 Analog Multiplexer
Test Circuits/Timing Diagrams (continued)
MAX14778
A_
V
IN
B_
ENA
LOGIC
INPUT
ENB
CL INCLUDES FIXTURE AND STRAY CAPACITANCE.
V
= V
(
OUT
IN
RL + R
Figure 3. Turn-On/Turn-Off Timing
SA0
ENA
MAX14778
SA1
LOGIC
INPUT
A_
V
IN
RL
+5V
V
DD
GND
ON
ACOM
BCOM
)
1µF
ACOM
t
OFF
80%
tR < 20ns
tF < 20ns
0.1 x V
t
BBM
OUT
V
IH
LOGIC
INPUT
V
V
OUT
R
C
L
R
L
SWITCH
OUTPUT
LOGIC
INPUT
V
C
L
L
OUT
SWITCH
OUTPUT
IL
0V
+5V
0V
V
OUT
0V
V
t
50%
OUT
ON
0.9 x V
tR < 20ns
0UT
CL INCLUDES FIXTURE AND STRAY CAPACITANCE.
V
OUT
= V
RL
(
IN
RL + R
Figure 4. Break-Before-Make Timing
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ON
)
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