TPS70751MPWPREP datasheet(33/41 Pages) TI1

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ESR1

ESR2

ESR3

Regulator Protection

TPS70751-EP

DUAL-OUTPUT LOW-DROPOUT VOLTAGE REGULATOR

WITH POWER-UP SEQUENCING FOR SPLIT-VOLTAGE DSP SYSTEMS

SLVS718 – DECEMBER 2006

Figure 42. Correlation of Different ESRs and Their Influence to the Regulation of VO

at a Load Step From Low-to-High Output Current

Both TPS70751 PMOS-pass transistors have built-in back diodes that conduct reverse currents when the input

voltage drops below the output voltage (e.g., during power down). Current is conducted from the output to the

input and is not internally limited. When extended reverse voltage is anticipated, external limiting may be

appropriate.

The TPS70751 also features internal current limiting and thermal protection. During normal operation, the

TPS70751 regulator 1 limits output current to approximately 1.6 A (typ) and regulator 2 limits output current to

approximately 750 mA (typ). When current limiting engages, the output voltage scales back linearly until the

overcurrent condition ends. While current limiting is designed to prevent gross device failure, care should be

taken not to exceed the power dissipation ratings of the package. If the temperature of the device exceeds

150

°C (typ), thermal-protection circuitry shuts it down. Once the device has cooled below 130°C (typ),

regulator operation resumes.

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TPS70751MPWPREP Datasheet(PDF) 33 Page - Texas Instruments