_

+

VIN

UVLO

Control

Logic

Ref

Output Discharge

GND

ON

VOUT

TPS22934

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SLVSAD4B – AUGUST 2010 – REVISED APRIL 2015

8 Detailed Description

8.1 Overview

The TPS22934 is a single-channel, 1-A load switch in a small, space-saving DSBGA-4 package. These devices

implement a P-channel MOSFET to provide a low ON-resistance for a low voltage drop across the device. A

controlled rise time is used in applications to limit the inrush current. The switch is controlled by an ON/OFF input

(ON), which has built-in hysteresis (VTH+(typ) = 2.35 V) allowing an easy use of TPS22934 in power-rail

sequencing applications.

8.2 Functional Block Diagram

8.3 Feature Description

Table 2. Feature List

SLEW RATE

QUICK

MAXIMUM

rON (TYP)

(TYP)

OUTPUT

OUTPUT

ENABLE

AT 3.6 V

AT 3.6 V

DISCHARGE

CURRENT

Hysteresis Input

TPS22934

63 m

Ω

26 µs

Yes

1 A

VTH+(typ) = 2.35 V

8.3.1 ON and OFF Control

The ON pin controls the state of the switch. The TPS22934 has built-in hysteresis on its control inputs. The load

switch is active when the ON voltage is greater than the positive going voltage threshold (VTH+). If the ON voltage

is lower than the negative going voltage threshold (VTH-), then the pass FET is deactivated and the active

pulldown from VOUT to GND is activated.

This scenario is ideal for power-rail sequencing applications as shown in Figure 30 where the 2.8-V supply must

be valid before the 1.8-V supply turnon.

8.3.2 Undervoltage Lockout

The undervoltage lockout turns off the switch if the input voltage drops below the undervoltage lockout threshold.

With the ON pin active, the input voltage rising above the undervoltage lockout threshold causes a controlled

turnon of the switch, which limits current overshoots.

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