18 k

126 k

-IN

+IN

Gain_Set

V+

V-

Out

ILIM

EN

IQSET

IFLAG

TFLAG

Limits & Alarms

Differential

Amplifier

Output

Stage

Voltage

Amplifier

7

OPA521

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SBOS872 – MAY 2018

Product Folder Links: OPA521

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Copyright © 2018, Texas Instruments Incorporated

7 Detailed Description

7.1 Overview

The OPA521 is a power amplifier designed for power line communication (PLC) applications. The device

features a fixed gain of –7 V/V, low-pass filter response, excellent linearity and low distortion through the

bandwidth. The amplifier operates with 7-V to 24-V supplies, and can deliver up to ±1.9 A of continuous current

from –40°C to +125°C.

7.2 Functional Block Diagram

7.3 Feature Description

The OPA521 offers an optional output current limit (ILIM), quiescent current (IQSET) selection pins, and a device

enable pin. The IFLAG output alarm pin indicates an output current warning and the TFLAG alarm triggers when

the internal temperature of the device forces the devices to shut down.

7.4 IQSET Pin

This pin sets the operating band of the amplifier by adjusting the quiescent current.

•

IQSET > 2 V sets the device to operate in the FCC or ARIB bands

•

IQSET < 0.8 V sets the device to operate in the CENELEC bands

7.5 EN Pin

When the transmitter is not in use, the output is disabled and placed in a high-impedance state when the EN

pin decreases. For typical operation, connect the EN pin to 3.3 V. In disabled mode, the entire device draws

40 μA (typical) of current.

7.6 ILIM Pin Current Limiting

The ILIM pin (pin 12) provides a resistor-programmable output current limit. Equation 1 determines the value of

where: