MAX4614/MAX4615/MAX4616
Low-Voltage, High-Speed, Quad, SPST
CMOS Analog Switches
8 _______________________________________________________________________________________
Applications Information
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 20mA, 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 6V.
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 sup-
ply voltage is below the absolute maximum rating, and
if a fault voltage up to the absolute maximum rating is
applied to an analog signal pin, no damage will result.
INCLUDES FIXTURE AND STRAY CAPACITANCE.
