
February 2000
1
MIC2526
MIC2526
Micrel
MIC2526
Dual USB Power Control Switch
Not Recommended for New Designs
Refer to MIC2026
General Description
The MIC2526 is a dual integrated high-side power switch with
independent enable and flag functions, optimized for self-
powered and bus-powered Universal Serial Bus (USB) appli-
cations. Few external components are necessary to satisfy
USB requirements.
The MIC2526 satisfies the following USB requirements: each
switch channel 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 require-
ments; and a flag output is available to indicate fault condi-
tions 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.
Additional features include thermal shutdown to prevent
catastrophic switch failure from high-current loads,
undervoltage lockout (UVLO) to ensure that the device re-
mains off unless there is a valid input voltage present, and
3.3V and 5V logic compatible enable inputs.
The MIC2526 is available in active-high and active-low ver-
sions in 8-pin DIP and SOIC packages.
Typical Application
ENA
FLGA
FLGB
ENB
OUTA
IN
GND
OUTB
ON/OFF
OVERCURRENT
OVERCURRENT
ON/OFF
MIC2526-2
3.3V USB Controller
V
CC
5.0V
0.1μF
V
BUS
D+
D
–
GND
Data
(Two Pair)
to USB
Controller
V
BUS
D+
D
–
GND
USB
Port 2
USB
Port 1
10k
100k
MIC5207-3.3
IN
OUT
GND
47μF
47μF
Ferrite
Beads
4.50V to 5.25V
Upstream V
BUS
100mA max.
V
BUS
D+
D
–
GND
Data
1μF
1μF
10k
100k
VIN
2-Port USB Self-Powered Hub
Features
Compliant to USB specifications
UL Recognized Component
2 independent switches
3V to 5.5V input
500mA minimum continuous load current per port
140m
maximum on-resistance
1.25A maximum short circuit current limit
Individual open-drain fault flag pins
110
μ
A typical on-state supply current
1
μ
A typical off-state supply current
Output can be forced higher than input (off-state)
Thermal shutdown
2.4V typical undervoltage lockout (UVLO)
1ms turn-on (soft-start) and fast turnoff
Active-high or active-low enable versions
8-pin SOIC and DIP packages
Applications
USB host and self-powered hubs
USB bus-powered hubs
Hot plug-in power supplies
Battery-charger circuits
UL Recognized Component
Micrel, Inc. 1849 Fortune Drive San Jose, CA 95131 USA tel + 1 (408) 944-0800 fax + 1 (408) 944-0970 http://www.micrel.com