OPA365-EP_15 Datasheet, PDF (9/22 Pages) Texas Instruments – 50-MHz Low-Distortion High-CMRR Rail-to-Rail I/O, Single-Supply Operational Amplifier

OPA365-EP
www.ti.com
SLOS735 – AUGUST 2011
Figure 3 shows a single-supply, electret microphone application where V_CM is provided by a resistive divider. The
divider also provides the bias voltage for the electret element.
Clean 3.3V Supply
49kΩ
4kΩ
3.3V
OPA365
V_OUT
Electret
6kΩ
5kΩ
Microphone
1µF
Figure 3. Microphone Preamplifier
Input and ESD Protection
The OPA365 incorporates internal electrostatic discharge (ESD) protection circuits on all pins. In the case of
input and output pins, this protection primarily consists of current steering diodes connected between the input
and power-supply pins. These ESD protection diodes also provide in-circuit, input overdrive protection, provided
that the current is limited to 10 mA as stated in the Absolute Maximum Ratings. Figure 4 shows how a series
input resistor may be added to the driven input to limit the input current. The added resistor contributes thermal
noise at the amplifier input and its value should be kept to the minimum in noise-sensitive applications.
I_OVERLOAD
10mA max
V_IN
5kΩ
V+
OPA365
V_OUT
Figure 4. Input Current Protection
Copyright © 2011, Texas Instruments Incorporated
Product Folder Link(s): OPA365-EP
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