+

–

Band Gap

Thermal

Shutdown

UVLO

Logic

Current

Limit

95

IN

EN

GND

OUT

FB

+

–

PG

0.90 x VREF

15

TPS746

www.ti.com

SBVS337A – APRIL 2018 – REVISED DECEMBER 2018

Product Folder Links: TPS746

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7 Detailed Description

7.1 Overview

The TPS746 is a next-generation, low-dropout regulator (LDO). This device consumes low quiescent current and

delivers excellent line and load transient performance. These characteristics, combined with low noise and good

PSRR with low dropout voltage, make this device ideal for portable consumer applications.

This regulator offers foldback current limit, shutdown, and thermal protection. The operating junction temperature

for this device is –40°C to +125°C.

7.2 Functional Block Diagram

7.3 Feature Description

7.3.1 Undervoltage Lockout (UVLO)

The TPS746 uses an undervoltage lockout (UVLO) circuit that disables the output until the input voltage is

greater than the rising UVLO voltage (VUVLO). This circuit ensures that the device does not exhibit any

unpredictable behavior when the supply voltage is lower than the operational range of the internal circuitry. When

VIN is less than VUVLO, the output is connected to ground with a pulldown resistor (RPULLDOWN).

7.3.2 Shutdown

The enable pin (EN) is active high. Enable the device by forcing the EN pin to exceed VEN(HI). Turn off the device

by forcing the EN pin to drop below VEN(LO). If shutdown capability is not required, connect EN to IN.

The TPS746 has an internal pulldown MOSFET that connects an RPULLDOWN resistor to ground when the device

is disabled. The discharge time after disabling depends on the output capacitance (COUT) and the load resistance

(RL) in parallel with the pulldown resistor (RPULLDOWN). Equation 1 calculates the time constant:

τ = ( RPULLDOWN × RL) / (RPULLDOWN + RL)

(1)