Datasheet
MAX398/MAX399
Applications Information
Operation with Supply Voltages
Other than ±5V
Using supply voltages less than ±5V reduces the analog
signal range. The MAX398/MAX399 muxes operate with
±3V to ±8V bipolar supplies or with a +3V to +15V single
supply. Connect V- to GND when operating with a single
supply. Both device types can also operate with unbal-
anced supplies, such as +10V and -5V. The Typical
Operating Characteristics graphs show typical on-resis-
tance with ±3V, ±5V, +3V, and +5V supplies. (Switching
times increase by a factor of two or more for operation at
+5V.)
Overvoltage Protection
Proper power-supply sequencing is recommended for
all CMOS devices. Do not exceed the absolute maxi-
mum ratings, because stresses beyond the listed rat-
ings can cause permanent damage to the devices.
Always sequence V+ on first, then V-, followed by the
logic inputs, NO, or COM. If power-supply sequencing
is not possible, add two small signal diodes (D1, D2) in
series with supply pins for overvoltage protection
(Figure 1). Adding diodes reduces the analog signal
range to one diode drop below V+ and one diode drop
above V-, but does not affect the devices’ low switch
resistance and low leakage characteristics. Device
operation is unchanged, and the difference between
V+ and V- should not exceed 17V. These protection
diodes are not recommended when using a single supply.
Precision, 8-Channel/Dual 4-Channel,
Low-Voltage, CMOS Analog Multiplexers
8 _______________________________________________________________________________________
Test Circuits/Timing Diagrams
COM
V-
V+
NO
* INTERNAL PROTECTION DIODES
D2
D1
-5V
+5V
MAX398
MAX399
*
*
*
*
Figure 1. Overvoltage Protection Using External Blocking Diodes
50%
t
TRANS
t
R
< 20ns
t
F
< 20ns
V
OUT
+3V
0
V
NO1
0
V
NO8
LOGIC
INPUT
V
EN
SWITCH
OUTPUT
+5V
V
OUT
-5V
GND
V+
A1
V-
A2
A0
EN
NO1
NO2–NO7
NO8
COM
+5V
-5V
50Ω
MAX398
300Ω
35pF
+5V
V
OUT
-5V
GND
V+
A0
V-
A1
EN
NO1B
NO1A–NO4A
NO4B
COMB
+5V
50Ω
MAX399
300Ω
35pF
90%
90%
t
TRANS
ON
-5V
V
EN
V
EN
Figure 2. Transition Time