OPA1611 Datasheet, PDF(14/21 Page) Texas Instruments – High-Performance Bipolar-Input AUDIO OPERATIONAL AMPLIFIERS

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OPA1611

OPA1612

SBOS450A â JULY 2009 â REVISED AUGUST 2009........................................................................................................................................................ www.ti.com

POWER DISSIPATION

OPA1611 and OPA1612 series op amps are capable

of driving 2kâ¦ loads with a power-supply voltage up

to Â±18V. Internal power dissipation increases when

operating at high supply voltages. Copper leadframe

construction used in the OPA1611 and OPA1612

series op amps improves heat dissipation compared

to conventional materials. Circuit board layout can

also help minimize junction temperature rise. Wide

copper traces help dissipate the heat by acting as an

additional heat sink. Temperature rise can be further

minimized by soldering the devices to the circuit

board rather than using a socket.

ELECTRICAL OVERSTRESS

Designers often ask questions about the capability of

an operational amplifier to withstand electrical

overstress. These questions tend to focus on the

device inputs, but may involve the supply voltage pins

or even the output pin. Each of these different pin

functions have electrical stress limits determined by

the voltage breakdown characteristics of the

particular semiconductor fabrication process and

specific circuits connected to the pin. Additionally,

internal electrostatic discharge (ESD) protection is

built into these circuits to protect them from

accidental ESD events both before and during

product assembly.

It is helpful to have a good understanding of this

basic ESD circuitry and its relevance to an electrical

overstress event. Figure 34 illustrates the ESD

circuits contained in the OPA161x series (indicated

by the dashed line area). The ESD protection circuitry

involves several current-steering diodes connected

from the input and output pins and routed back to the

internal power-supply lines, where they meet at an

absorption device internal to the operational amplifier.

This protection circuitry is intended to remain inactive

during normal circuit operation.

An ESD event produces a short duration,

high-voltage pulse that is transformed into a short

duration, high-current pulse as it discharges through

a semiconductor device. The ESD protection circuits

are designed to provide a current path around the

operational amplifier core to prevent it from being

damaged. The energy absorbed by the protection

circuitry is then dissipated as heat.

When an ESD voltage develops across two or more

of the amplifier device pins, current flows through one

or more of the steering diodes. Depending on the

path that the current takes, the absorption device

may activate. The absorption device has a trigger, or

threshold voltage, that is above the normal operating

voltage of the OPA161x but below the device

breakdown voltage level. Once this threshold is

exceeded, the absorption device quickly activates

and clamps the voltage across the supply rails to a

safe level.

Product Folder Link(s): OPA1611 OPA1612

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