Power-Supply Sequencing
and Overvoltage Protection
Do not exceed the absolute maximum ratings because
stresses beyond the listed ratings may cause perma-
nent damage to the devices.
Proper power-supply sequencing is recommended for
all CMOS devices. Always apply V+ before applying
analog signals or logic inputs, especially if the analog
or logic signals are not current limited. If this sequenc-
ing is not possible, and if the analog or logic inputs are
not current limited to < 10mA, add a small-signal diode
(D1) as shown in Figure 1. If the analog signal can dip
below GND, add D2. Adding protection diodes
reduces the analog signal range to a diode drop (about
0.7V) below V+ (for D1), and to a diode drop above
ground (for D2). Leakage is unaffected by adding the
diodes. On-resistance increases by a small amount at
low supply voltages. Maximum supply voltage (V+)
must not exceed 13V.
Adding protection diodes causes the logic thresholds
to be shifted relative to the power-supply rails. This can
be significant when low supply voltages (+5V or less)
are used. With a +5V supply, TTL compatibility is not
guaranteed when protection diodes are added. Driving
IN1 and IN2 all the way to the supply rails (i.e., to a
diode drop higher than the V+ pin, or to a diode drop
lower than the GND pin) is always acceptable.
Protection diodes D1 and D2 also protect against
some overvoltage situations. With Figure 1’s circuit, if
the supply voltage is below the absolute maximum rat-
ing, and if a fault voltage up to the absolute maximum
rating is applied to an analog signal pin, no damage
will result.
MAX4541–MAX4544
Low-Voltage, Single-Supply
Dual SPST/SPDT Analog Switches
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