MAX14778_12 Datasheet, PDF(11/15 Page) Maxim Integrated Products – Dual ±25V Above- and Below-the-Rails 4:1 Analog Multiplexer

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MAX14778

Dual Â±25V Above- and Below-the-Rails

4:1 Analog Multiplexer

Non-Powered Condition

The MAX14778 can tolerate input voltages on the A_, B_,

ACOM, and BCOM pins in the Â±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 1ÂµA.

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/Âµs 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 VP

and VN 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.

1MI

1.5kI

CHARGE CURRENT-

LIMIT RESISTOR

DISCHARGE

RESISTANCE

HIGH-

VOLTAGE

SOURCE

100pF

STORAGE

CAPACITOR

Figure 7. Human Body ESD Test Model

DEVICE

UNDER

TEST

IP 100%

90%

AMPERES

36.8%

10%

0 tRL

PEAK-TO-PEAK RINGING

(NOT DRAWN TO SCALE)

TIME

tDL

CURRENT WAVEFORM

Figure 8. Human Body Current Waveform

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