Texas Instruments UCC3912PWP, UCC3912N, UCC3912DPTR, UCC3912DPRTR, UCC3912DPR Datasheet

UCC3912

SLUS241A - NOVEMBER 1999

FEATURES

•

Integrated 0.15Ω Power MOSFET

•

3V to 8V Operation

•

Digital Programmable Current Limit
from 0 to 3A

•

Electronic Circuit Breaker Function

•

1µA I

CC

when Disabled

•

Programmable on Time

•

Programmable Start Delay

•

Fixed 3% Duty Cycle

•

Uni-Directional Switch

•

Thermal Shutdown

• Fault Output Indicator

• Maximum Output Current can be set

to 1A above the Programmed Fault
Level or to a full 4A

• Power SOIC, Low Thermal

Resistance Packaging

DESCRIPTION

The UCC3912 Hot Swap Power Manager provides complete power man

-

agement, hot swap capability, and circuit breaker functions. The only com

­ponent required to operate the device, other than supply bypassing, is the
fault timing capacitor, C

T

. All control and housekeeping functions are inte

­grated, and externally programmable. These include the fault current level,
maximum output sourcing current, maximum fault time,and start-up delay.
In the event of a constant fault, the Internal fixed 3% duty cycle ratio limits
average output power.

The internal 4 bit DAC allows programming of the fault level current from 0
to 3A with 0.25A resolution. The IMAX control pin sets the maximum sour

­cing current to 1A above the fault level when driven low, and to a full 4A
when driven high for applications which require fast output capacitor charg

­ing.

When the output current is below the fault level, the output MOSFET is
switched on with a nominal on resistance of 0.15

. When the output cur

­rent exceeds the fault level, but is less than the maximum sourcing level,
the output remains switched on, but the fault timer starts charging C

T

.

Once C

T

charges to a preset threshold, the switch is turned off, and re­mains off for 30 times the programmed fault time. When the output current
reaches the maximum sourcing level, the MOSFET transitions from a
switch to a constant current source.

(continued)

6 7 8 9

1A

ABOVE

FAU LT

OVER CURRENT

COMPARATOR
CURRENT FAULT
LEVEL 0–3 AMPS

10

H=4A

MAX

CURRENT

LEVEL

4A

ON TIME

CONTROL

3% DUTY

CYCLE

0–3A

0.25
RES

1113 1245

B3 B2 B1 B0

4BITDAC

GND

HEAT SINK

GND PINS

CT

CHARGE

PUMP

+

16

LINEAR CURRENT

AMPLIFIER

POWER

FET

2

3

V

OUT

REVERSE VOLTAGE
COMPARATOR

30mV

FAU LT

THERMAL

SHUTDOWN

INTERNAL

BIAS

+

–

1

15

14

VOUT

VIN

CURRENT SENSE

H = OPEN

1.5V

SHTDWN

IMAX

BLOCK DIAGRAM

Programmable Hot Swap Power Manager

UDG-99146

application

INFO

available

2

UCC3912

VIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +8 V

FAULT

Sink Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50mA

FAULT

Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 to V

IN

Output Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . Self Limiting

Input Voltage

(B0, B1, B2, B3, IMAX, SHTDWN

) . . . . . . . . . . . –0.3 to V

IN

Storage Temperature Range . . . . . . . . . . . . . –65°C to +150°C

Operating Junction Temperature Range . . . . –55°C to +150°C

Lead Temperature (Soldering, 10 sec.) . . . . . . . . . . . . . +300°C

Currents are positive into, negative out of the specified termi

-

nal. Consult Packaging Section of Databook for thermal limita

-

tions and considerations of packages.

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS:

Unless otherwise stated, these specifications apply for TJ = 0°C to 70°C, VIN = 5V,

IMAX = 0.4V, SHTDWN

= 2.4V.

PARAMETER TEST CONDITIONS MIN TYP MAX UNITS

Supply Section

Voltage Input Range 3.0 8.0 V

Supply Current 1.0 2.0 mA

Sleep Mode Current SHTDWN

= 0.2V 0.5 5.0 µA

Output Section

Voltage Drop I

OUT

= 1A 0.15 0.22 V

I

OUT

= 2A 0.3 0.45 V

I

OUT

= 3A 0.45 0.68 V

I

OUT

= 1A, VIN = 3V 0.17 0.27 V

I

OUT

= 2A, VIN = 3V 0.35 0.56 V

I

OUT

= 3A, VIN = 3V 0.5 0.8 V

CONNECTION DIAGRAMS

*Pin 5 serves as lowest impedance to the electrical ground;

Pins 4, 12, and 13 serve as heat sink/ground. These pins
should be connected to large etch areas to help dissipate
heat. For N package, pins 4, 12, and 13 are N/C.

The UCC3912 is designed for unidirectional current flow,
emulating an ideal diode in series with the power switch.
This feature is particularly attractive in applications
where many devices are powering a common bus, such
as with SCSI Termpwr.

The UCC3912 can be put into sleep mode drawing only
1µA of supply current. The SHTDWN

pin has a preset
threshold hysteresis which allows the user the ability to
set a time delay upon start-up to achieve sequencing of
power. Other features include an open drain FAULT out

-

put indicator, Thermal Shutdown, Under Voltage Lock

-

out, and a low thermal resistance Small outline package.

DESCRIPTION (cont.)

B3

N/C

GND*

GND*

FAU LT

VIN

EGND*

GND*

GND*

VIN

N/C

GND*

SHTDWN

GND*

B2

GND*

GND*

CT

12

11

10

9

8

7

6

5

4

3

2

1

13

14

15

16

17

18

19

20

21

22

23

24

IMAX

VOUT

VOUT

B1 B0

GND*

TSSOP-24 (Top View)
PWP Package

DIL-16, SOIC-16 (Top View)
N, DP Package

*Pin 9 serves as lowest impedance to the electrical ground;

other GND pins serve as heat sink/ground. These pins
should be connected to large etch areas to help dissipate
heat.