Datasheet

MAX14778
Dual ±25V Above- and Below-the-Rails
4:1 Analog Multiplexer
11Maxim Integrated
Non-Powered Condition
The MAX14778 can tolerate input voltages on the A_, B_,
ACOM, and BCOM pins in the ±25V range when it is not
powered.
When VDD = 0V, the DC input leakage current into the
A_, B_, ACOM or BCOM pins will typically be below 1µA.
Some devices can have a larger leakage current up to
mA range due to technology spread.
With VDD not powered, internal diodes between the ana-
log pins and the VP and VN will charge up the external
capacitors on VP and VN when positive and/or negative
voltages are applied to these pins. This causes transient
input current flow.
Large dv/dt on the inputs causes large capacitive charg-
ing currents, which have to be limited to the 300mA
Absolute Maximum Ratings in order to not destroy the
internal diodes. With 100nF capacitors on VP and VN, the
dv/dt must be limited to 3V/µs once the capacitors reach
their final voltage; the input current decays to the leakage
current levels mentioned above.
High-ESD Protection
Electrostatic discharge (ESD)-protection structures are
incorporated on all pins to protect against electrostatic
discharges up to Q2kV Human Body Model (HBM)
encountered during handling and assembly. A_ and B_
are further protected against ESD up to Q6kV (HBM)
without damage. The ESD structures withstand high ESD
both in normal operation and when the device is powered
down. After an ESD event, the MAX14778 continues to
function without latchup.
ESD Test Conditions
ESD performance depends on a variety of conditions.
Contact Maxim for a reliability report that documents test
setup, test methodology, and test results.
The MAX14778 requires a 100nF capacitor on both V
P
and V
N
to GND to guarantee full ESD protection.
Human Body Model
Figure 7 shows the Human Body Model. Figure 8 shows
the current waveform it generates when discharged
into a low impedance. This model consists of a 100pF
capacitor charged to the ESD voltage of interest that is
then discharged into the device through a 1.5kI resistor.
Figure 7. Human Body ESD Test Model Figure 8. Human Body Current Waveform
CHARGE CURRENT-
LIMIT RESISTOR
DISCHARGE
RESISTANCE
STORAGE
CAPACITOR
C
S
100pF
R
C
1MI
R
D
1.5kI
HIGH-
VOLTAGE
DC
SOURCE
DEVICE
UNDER
TEST
36.8%
t
RL
TIME
t
DL
CURRENT WAVEFORM
PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)
I
r
10%
0
0
AMPERES
I
P
100%
90%