TS2023

1A Single Channel USB Power Switch

4/8

Version: A11

Application Information

Flag Output

An error Flag is an open-drained output of an N-channel MOSFET. Flag output is pulled low to signal the following

fault conditions: input under-voltage, output current limit, and thermal shutdown. The current limit flag response

delay time is 9ms.

Current Limit

The current limit threshold is preset internally. It protects the output MOSFET switches from damage resulting from

undesirable short circuit conditions or excess inrush current, which is often encountered during hot plug-in. The

error flag signals when any current limit conditions occur.

Thermal Shutdown

When temperature of TS2023 exceeds 145ºC for any reasons, the thermal shutdown function turns MOSFET

switch off and signals the error flag. A hysteresis of 20ºC prevents the MOSFETs from turning back on until the

chip temperature drops below 125ºC.

Enable Control

Enable must be driven logic low for a clearly defined input. Floating the input may cause unpredictable operation

Under-Voltage Lockout

UVLO (under-voltage lockout) prevents the output MOSFET from turning on until input voltage exceeds 2.5V

typically. After the switch turns on, if the input voltage drops below 2.3V typically, UVLO shuts off the output

MOSFET.

Supply Filtering

A 1uF bypass capacitor from USB IN to GND, located near the device, is strongly recommended to control supply

transients. Without a bypass capacitor, an output short may cause sufficient ringing on the input (from supply lead

inductance) to damage internal control circuitry

Transient Requirements

USB supports dynamic attachment (hot plug-in) of peripherals. A current surge is caused by the input capacitance

of downstream device. Ferrite beads are recommended in series with all power and ground connector pins. Ferrite

beads reduce EMI and limit the inrush current during hot attachment by filtering high-frequency signals.

Short Circuit Transient

Bulk capacitance provides the short-term transient current needed during a hot-attachment event. A 22uF/10V

ceramic capacitor mounted close to downstream connect each port should provide transient drop protection

Printed Layout Circuit

The power circuitry of USB printed circuit boards requires a customized layout to maximize thermal dissipation and

to minimize voltage drop and EMI