11/98
FEATURES
Fully USB Compliant
Support Four 5V Peripherals and One
USB 3.3V Controller
Separate Power Enables
500mA Current Limiting per Channel
Separate Open Drain Fault Indicator
for Each Channel
3.3V Output for USB Controller
Available in 28 Pin Wide Surface
Mount and DIP
Universal Serial Bus Hot Swap Power Controller
APPLICATION AND BLOCK DIAGRAM
UCC3981
PRELIMINARY
UDG-97101
DESCRIPTION
The UCC3981 Hot Swap Power Controller is designed to provide a self
powered USB hub with a local 3.3V regulated voltage and four 5V regu-
lated voltages for USB ports. Each of the 5V output ports is individually
enabled for optimal port control. Each port also provides an overcurrent
fault signal indicating that the port has exceeded a 500mA current limit.
The 3.3V linear regulator is used to power the local USB microcontroller.
This regulator is protected with a 100mA current limit and has a logic
level enable input.
The UCC3981 can be configured to provide USB port power from a
loosely regulated voltage such as a Filament voltage internal to a monitor.
Pre-regulation is provided by an internal linear regulator controller and
one external logic level N-channel MOSFET. The UCC3981 can also be
configured without using the pre-regulator stage by connecting the VREG
pins to a regulated 5.5V 2A source.
The UCC3981 comes in a 28-pin wide SOIC power package optimized
for power dissipation, and is protected by internal over-temperature shut-
down mechanism, which disables the outputs should the internal junction
temperature exceed 150C.
UCC3981 USB HUB POWER CONTROLLER
2
UCC3981
ELECTRICAL CHARACTERISTICS
Unless otherwise specified, T
J
= 0C to 125C for the UCC3981. VFIL = 6.5V,
VHUB = 5V. T
A
= T
J
.
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNITS
Input Supply Currents
VHUB Supply Current
No External Load on V33
1
3
mA
VFIL Supply Current
1
3
mA
Reference
VREF Voltage
Over Temperature
2.35
2.5
2.65
V
Line Regulation
VHUB = 4.5V to 9V
3
10
mV
3.3V Regulator
V33 Voltage
T
J
= 25C, I
LOAD
= 10mA
3.2
3.3
3.4
V
0mA to 100mA, 0C to 125C, VHUB = 4.5V to 9V
3.165
3.3
3.435
V
Short Circuit Current Limit
VHUB = 6V, Output shorted to Ground
100
120
150
mA
Pre-Regulator
VREG Voltage
0A to 2A, 0C to 125C, VFIL = 6V to 9V
5.25
5.5
5.7
V
5V Regulator
V5A-D Voltage
T
J
= 25C, I
LOAD
= 250mA, V
REG
= 5.5V
4.85
5
5.15
V
0mA to 500mA, 0C to 125C
4.8
5
5.2
V
Short Circuit Current Limit
VREG = 5.5V, Output Shorted to Ground
500
600
750
mA
Charge Pump
Quiescent Output Voltage
T
J
= 25C, VFIL = 6V, ENA-D = 5V, ENHUB = 5V
11
11.45
12
V
0C to 125C, VFIL = 6V
10.5
11.45
12
V
Output Impedance
9
15
k
VFIL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9V
VCON Supply Votage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9V
Logic Inputs (ENA-D, ENHUB)
Maximum Forced Voltage . . . . . . . . . . . . . . . . . 0.3V to 7V
Maximum Forced Current . . . . . . . . . . . . . . . . . . . . . .
1mA
V33
Maximum Forced Voltage. . . . . . . . . . . . . . . . . . . . . . . . . 5V
Maximum Current . . . . . . . . . . . . . . . . . . . . . . . . . . . 200mA
V5A-D
Maximum Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9V
Maximum Current . . . . . . . . . . . . . . . . . . . . . . . . . . . 750mA
Storage Temperature . . . . . . . . . . . . . . . . . . .
-
65C to +150C
Junction Temperature . . . . . . . . . . . . . . . . . . . 55C to +150C
Lead Temperature (Soldering, 10 sec.) . . . . . . . . . . . . . +300C
Unless otherwise indicated, voltages are reference to ground.
Pulsed is defined as a less than 10% duty cycle with a maximum
duration of 500
m
S. Currents are positive into, negative out of the
specified terminal. All voltages are with respect to ground. Con-
sult Packaging Section of Databook for thermal limitations and
considerations of packages.
ABSOLUTE MAXIMUM RATINGS
CONNECTION DIAGRAM
SOIC-28 (Top View)
DWP Package
* DWP package pin 28 serves as signal ground;
Pins 7, 8, 9, 20, 21, 22 serve as heatsink/ground.
3
UCC3981
ENA-D: Separate enables pins for each of the four 5V
supplies.
ENHUB: Enables the 3.3V output V33. Pulling this pin
low disables V33.
GATE: Gate drive for an external NMOS used to regulate
the 5.5V VREG supply. Minimum available drive is 11V.
GND: All 6 GND pins must be tied to the system ground.
In addition to serving as electrical conductors, these 6
pins are heat sinks. Refer to the Packaging Device Tem-
perature Management guide in the Packaging section of
the Unitrode Databook.
OCA-D: Open drain overcurrent indicator. OCA-D can be
wire OR'ed by the user to create a single overcurrent in-
dicator.
V5A-D: 5V regulated output with enable, 500mA (mini-
mum) current limit, and overcurrent indicator.
V33: 3.3V regulator output. Enable when ENHUB is high.
Current limit is 100mA minimum.
VDRIVE: Internal charge pump voltage is brought out for
external decoupling. Nominal voltage is between 11V
and 13V. No external loading permitting. Decouple with
at least 0.001
F capacitor.
VFIL: Bias supply for all four of the 5V regulators. VFIL
voltage must be between 6V and 9V.
VHUB: Supply for the 3.3V USB controller power supply
and bandgap reference.
VREF: Internal 2.5V reference is brought out for external
decoupling only. Decouple with 0.01
F capacitor.
VREG: Regulated to 5.5V by means of an external
NMOS. Two pins supply up to a total of 2.5A to the four
5V bus voltages (V5A, V5B, V5C, V5D).
PIN DESCRIPTIONS
UNITRODE CORPORATION
7 CONTINENTAL BLVD. MERRIMACK, NH 03054
TEL. (603) 424-2410 FAX (603) 424-3460
ELECTRICAL CHARACTERISTICS
Unless otherwise specified, T
J
= 0C to 125C for the UCC3981. VFIL = 6.5V,
VHUB = 5V. T
A
= T
J
.
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNITS
Enable Inputs
ENA-D Inputs - Guaranteed Low
0.7
V
ENA-D Inputs - Guaranteed High
3
V
ENHUB Input - Guaranteed Low
0.7
V
ENHUB Input - Guaranteed High
3
V
Overcurrent Signals
Active Sink Current
I
OCX
=100
m
A
140
500
mV
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Copyright
1999, Texas Instruments Incorporated
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