19-5929; Rev 1; 6/12
EVALUATION KIT AVAILABLE
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 multiplex-
er 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.
S
±25V Signal Range
S
Single 3.0V to 5.5V Supply
S
Two Independent Multiplexers
S
1.5I R
ON
(max)
S
3mI R
ON
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 A½ and B½ 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.
Features
Applications
RS-485/RS-232/USB 1.1 Multiplexing
POS Peripherals
Handheld Industrial Devices
Communication Systems
Audio/Data Multiplexing
Connector Sharing
Gaming Machines
A0
A1
ENA
SA0
Functional Diagram
SA1
V
DD
BIAS
GENERATION
V
P
V
N
CONTROL A
MAX14778
ACOM
A2
A3
B0
B1
BCOM
B2
B3
CONTROL B
ENB
SB0
SB1
GND
½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½
Maxim Integrated Products
1
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.)
V
DD
..........................................................................-0.3V to +6V
V
P
........................... -0.3V to the lesser of +52V and (V
N
+ 70V)
V
N
................ The lesser of (V
DD
- 40V) and (V
P
- 70V) to +0.3V
V
P
to V
N
.................................................................-0.3V to +70V
ENA, ENB, SA_, SB_ ................................ -0.3V to (V
DD
+ 0.3V)
A_, ACOM, B_,
BCOM .. (V
N
- 0.3V) to the lesser of (V
P
+ 0.3V) and (V
N
+ 52V)
Continuous Current Through Switch ............................. ±500mA
Continuous Power Dissipation (T
A
= +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
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional opera-
tion 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 (B
JA
) ..........30NC/W
Junction-to-Case Thermal Resistance (B
JC
) .................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.
ELECTRICAL CHARACTERISTICS
(V
DD
= 3.0V to 5.5V, T
A
= -40NC to +85NC, unless otherwise noted. Typical values are at V
DD
= 5V, T
A
= +25NC.) (Note 2)
PARAMETER
DC CHARACTERISTICS
Supply Voltage Range
V
DD
ENA = ENB = high
Supply Current
I
DD
V
ENA
= V
ENB
= V
DD
/2
Charge-Pump Threshold
Analog Signal Range
Continuous Current
Through Switch
On-Resistance
On-Resistance Flatness
A_, B_ Off-Leakage
Current
ACOM, BCOM
Off-Leakage Current
A_, B_ On-Leakage
Current
V
DDTH
V
IN
I
COM
R
ON
R
FLAT(ON)
I
A(OFF)
,
I
B(OFF)
I
ACOM(OFF)
,
I
BCOM(OFF)
I
A(ON)
,
I
B(ON)
Figure 1, I
COM
=
Q300mA,
V
IN
=
Q25V
Figure 1, -25V
P
V
IN
P
+25V,
I
COM
=
Q300mA
Figure 2, V
IN
= 25V, V
OUT
= 0V
Figure 2, V
OUT
= 15V, V
IN
= 0V
Figure 2, V
IN
=
Q25V,
ACOM or BCOM
is unconnected
-200
-1
-1
(Note 3)
Figure 1, switch open or closed
-25
-300
0.84
3
+200
+1
+1
V
DD
P
V
DDTH
V
DD
> V
DDTH
V
DD
P
V
DDTH
V
DD
> V
DDTH
3.0
4.27
2.54
4.31
2.59
4.64
+25
+300
1.5
5.5
10
6
10
6
V
V
mA
Ω
mΩ
nA
FA
FA
mA
V
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
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Maxim Integrated Products
2
MAX14778
Dual ±25V Above- and Below-the-Rails
4:1 Analog Multiplexer
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= 3.0V to 5.5V, T
A
= -40NC to +85NC, unless otherwise noted. Typical values are at V
DD
= 5V, T
A
= +25NC.) (Note 2)
PARAMETER
SYMBOL
V
DD
= 5.5V
Input Logic-Low Voltage
V
IL
V
DD
= 4.5V
V
DD
= 3.6V
V
DD
= 3.0V
V
DD
= 5.5V
Input Logic-High Voltage
V
IH
V
DD
= 4.5V
V
DD
= 3.6V
V
DD
= 3.0V
AC CHARACTERISTICS
Power-Up Time
Enable Turn-On Time
Enable Turn-Off Time
Break-Before-Make
Interval
Charge Injection
Off-Isolation
Crosstalk
-3dB Bandwidth
Total Harmonic Distortion
Plus Noise
Input Capacitance
THERMAL PROTECTION
Thermal-Shutdown
Threshold
Thermal-Shutdown
Hysteresis
ESD PROTECTION
A_, B_ Pins (Note 4)
All Other Pins
Human Body Model
Human Body Model
Q6
Q2
kV
kV
T
SHUT
T
HYST
145
25
NC
NC
t
POR
t
ON
t
OFF
t
BBM
Q
V
ISO
V
CT
BW
THD+N
C
IN
Figure 3, V
IN
=
Q10V,
R
L
= 10kI,
C
L
= 15pF
Figure 3, V
IN
=
Q10V,
R
L
= 10kI,
C
L
= 15pF
Figure 4, V
IN
=
Q10V,
R
L
= 10kI,
C
L
= 15pF
Figure 5, V
A_
= 0V, C
L
= 1nF
Figure 6, V
A_
= 1V
RMS
, f = 100kHz,
R
L
= 50I, C
L
= 15pF
Figure 6, f = 100kHz, R
S
= R
L
= 50I
Figure 6, R
S
= 50I, R
L
= 50I
R
S
= R
L
= 1kI, f = 20Hz to 20kHz
A_, B_ pins
840
1720
-80
-103
75
0.003
78
404
2
1.5
ms
ms
ms
Fs
pC
dB
dB
MHz
%
pF
2.1
2.0
1.9
1.7
V
CONDITIONS
MIN
TYP
MAX
0.8
0.8
0.7
0.7
V
UNITS
LOGIC INPUTS (ENA, ENB, SA½, SB½)
Note 2:
All units are production tested at T
A
= +25NC. Specifications over temperature are guaranteed by design.
Note 3:
When V
DD
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 V
DD
.
Note 4:
The MAX14778 requires a 100nF capacitor on both V
P
and V
N
to GND to guarantee full ESD protection. See the
Applications Information
section for details on ESD test conditions.
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Maxim Integrated Products
3
MAX14778
Dual ±25V Above- and Below-the-Rails
4:1 Analog Multiplexer
Test Circuits/Timing Diagrams
V
+5V
1µF
V
DD
MAX14778
A_
B_
V
IN
GND
ACOM
BCOM
I
COM
Figure 1. On-Resistance Measurement
+5V
1µF
+5V
1µF
V
DD
I
A(OFF)
I
B(OFF)
V
DD
I
ACOM(OFF)
I
BCOM(OFF)
ACOM
BCOM
I
A(ON)
I
B(ON)
MAX14778
A_
B_
GND
MAX14778
A_
B_
GND
ACOM
BCOM
A
V
IN
A
V
OUT
V
IN
A
Figure 2. Leakage Current Measurement
½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½
Maxim Integrated Products
4
MAX14778
Dual ±25V Above- and Below-the-Rails
4:1 Analog Multiplexer
Test Circuits/Timing Diagrams (continued)
MAX14778
V
IN
A_
B_
ENA
ENB
LOGIC
INPUT
C
L
INCLUDES FIXTURE AND STRAY CAPACITANCE.
R
L
V
OUT
= V
IN
R + R
L
ON
ACOM
BCOM
R
L
V
OUT
LOGIC
INPUT
V
IH
V
IL
50%
t R < 20ns
t F < 20ns
C
L
V
OUT
SWITCH
OUTPUT
0V
t
ON
t
OFF
0.9 x V
0UT
0.1 x V
OUT
(
)
Figure 3. Turn-On/Turn-Off Timing
+5V
1µF
+5V
V
DD
SA0
ENA
SA1
LOGIC
INPUT
A_
V
IN
GND
ACOM
t
R
< 20ns
0V
LOGIC
INPUT
V
OUT
V
OUT
SWITCH
OUTPUT
0V
80%
MAX14778
R
L
C
L
t
BBM
C
L
INCLUDES FIXTURE AND STRAY CAPACITANCE.
R
L
V
OUT
= V
IN
R + R
L
ON
(
)
Figure 4. Break-Before-Make Timing
½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½
Maxim Integrated Products
5
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