June 1999

1

MIC2529

MIC2529

Micrel

MIC2529

Single-Channel USB Power Controller

Advance Information

General Description

The MIC2529 is a high-side power switch optimized for self-

powered (individual port switching) and bus-powered (ganged

port switching) Universal Serial Bus (USB) hub applications.

An on-board voltage regulator provides the 3.3V supply

voltage needed for many USB microcontrollers reducing

board component count.

The MIC2529 satisfies the following USB requirements: it

supplies up to 500mA as required by USB downstream

devices; the switch’s low on-resistance meets USB voltage

drop requirements; fault current is limited to typically 750mA,

well below the UL 25VA safety requirement; and a flag output

is available to indicate fault conditions to the local USB

controller. Soft start eliminates the momentary voltage drop

on the upstream port that may occur when the switch is

enabled in bus-powered applications.

A low-dropout (LDO) regulator provides 3.3V at loads up to

100mA and includes an enable pin for low current shutdown.

Both enable inputs are compatible with 3.3V and 5V logic.

Thermal shutdown prevents catastrophic failure from high-

current loads.

The MIC2529 is available in an 8-pin SOIC package with

active-high or active-low enable circuitry on switch.

Typical Applications

ON/OFF

OVERCURRENT

MIC2529

3.3V USB Controller

D+

D–

GND

D+

D–

GND

Ferrite

Bead

D–

D+

V+

EN

IN

FLG

OUT

OUT

3VOUT

Bold lines indicate

0.1" wide, 1-oz. copper

high-current traces.

Downstream

USB

Port 1

100mA max.

Downstream

USB

Port 2

100mA max.

D+

D–

GND

D+

D–

GND

3VEN

GND

Downstream

USB

Port 3

100mA max.

Downstream

USB

Port 4

100mA max.

0.01µF

0.01µF

0.01µF

0.01µF

GND

0.1

µF

1µF

83

12

67

54

1.5k*

5%

4.7

µF

* Speed sense termination resistor. Must be connected

†

33µF tantalum or 100µF electrolytics are recommended.

D+

D–

GND

10k

0.1µF

10k

4.40V to 5.25V

4-Port Ganged Bus-Powered Hub

Features

• Compliant to USB specifications

• UL Recognized Component

• On-board 3.3V, 100mA low-dropout regulator

• 500mA minimum continuous switch load current

• 160m

Ω maximum on-resistance

• 750mA typical current limit

• Open-drain fault flag pin for switch

• Output can be forced higher than input (off-state)

• Thermal shutdown

• 1ms turn-on (soft-start) and fast turnoff

• Available with active-high or active-low switch enable

• Active-high enable on 3.3V regulated output

• 8-pin SOIC package

Applications

• USB self-powered hubs

• USB bus-powered hubs

• USB keyboard hubs

UL Recognized Component