UVLO

Thermal

Shutdown

Current

Limit

Enable

Error

Amp

IN

EN

OUT

FB

Pass

Device

TPS7A4001-EP

SBVS226 – AUGUST 2015

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7 Detailed Description

7.1 Overview

The TPS7A4001-EP device belongs to a new generation of linear regulators that use an innovative BiCMOS

process technology to achieve very high maximum input and output voltages.

This process not only allows the TPS7A4001-EP device to maintain regulation during very fast high-voltage

transients up to 105 V, but it also allows the TPS7A4001-EP device to regulate from a continuous high-voltage

input rail. Unlike other regulators created using bipolar technology, the ground current of the TPS7A4001-EP

device is also constant over its output current range, resulting in increased efficiency and lower power

consumption.

These features, combined with a high thermal performance HVSSOP PowerPAD package, make this device

ideal for industrial and telecom applications.

7.2 Functional Block Diagram

7.3 Feature Description

7.3.1 Internal Current Limit

The fixed internal current limit of the TPS7A4001-EP device helps protect the regulator during fault conditions.

The maximum amount of current the device can source is the current limit (309 mA, typical), and is largely

independent of output voltage. For reliable operation, the device does not operate in current limit for extended

periods of time.

7.3.2 Enable Pin Operation

7.3.3 Thermal Protection

Thermal protection disables the output when the junction temperature rises to approximately 170°C, allowing the

device to cool. When the junction temperature cools to approximately 150°C, the output circuitry is enabled.

Depending on power dissipation, thermal resistance, and ambient temperature, the thermal protection circuit may

cycle on and off. This cycling limits the dissipation of the regulator, protecting it from damage as a result of

overheating.

Any tendency to activate the thermal protection circuit indicates excessive power dissipation or an inadequate

heatsink. For reliable operation, limit junction temperature to a maximum of 125°C. To estimate the margin of

safety in a complete design (including heatsink), increase the ambient temperature until the thermal protection is

triggered; use worst-case loads and signal conditions. For good reliability, trigger thermal protection at least 35°C

above the maximum expected ambient condition of your particular application. This configuration produces a

worst-case junction temperature of 125°C at the highest expected ambient temperature and worst-case load.

8

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