UCC281-3/-5/-ADJ
UCC381-3/-5/-ADJ
ABSOLUTE MAXIMUM RATINGS
VIN. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9V
CT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −0.3 to 3V
Storage Temperature . . . . . . . . . . . . . . . . . . . −65°C to +150°C
Junction Temperature . . . . . . . . . . . . . . . . . . . −55°C to +150°C
Lead Temperature (Soldering, 10 sec.) . . . . . . . . . . . . . +300°C
CONNECTION DIAGRAMS
SOIC-8 (Top View)
DP Package
VOUT 1
Currents are positive into, negative out of the specified terminal.
Consult Packaging Section of Databook for thermal limitations
and considerations of packages. All voltages are referenced to
GND.
GND 2
GND 3
VOUTS 4
8 VIN
7 GND
6 GND
5 CT*
DESCRIPTION (cont.)
Short circuit current is internally limited. The device re-
sponds to a sustained overcurrent condition by turning
off after a TON delay. The device then stays off for a pe-
riod, TOFF, that is 32 times the TON delay. The device
then begins pulsing on and off at the TON /(TON+TOFF)
duty cycle of 3%. This drastically reduces the power dis-
sipation during short circuit such that heat sinking, if at all
required, must only accommodate normal operation. On
the fixed output versions of the device TON is fixed at
400µs − a guaranteed minimum. On the adjustable ver-
sion an external capacitor sets the on time. The off time
is always 32 times TON.
* ADJ version only
The UCC381 can be shutdown to 25µA (max) by pulling
the CT pin low.
Internal power dissipation is further controlled with ther-
mal overload protection circuitry. Thermal shutdown oc-
curs if the junction temperature exceeds 165°C. The chip
will remain off until the temperature has dropped 20°C.
The UCC281 series is specified for operation over the in-
dustrial range of −40°C to +85°C, and the UCC381 se-
ries is specified from 0°C to +70°C. These devices are
available in the 8 pin DP surface mount power package.
For other packaging options consult the factory.
ELECTRICAL CHARACTERISTICS: Unless otherwise stated, these specifications hold for TA = 0°C to 70°C for the
UCC381-X series and −40°C to +85°C for the UCC283-X series, VIN = VOUT + 1.5V, IOUT = 0mA, COUT = 2.2µF. CT = 1500pF for
the UCC381-ADJ version and VOUT set to 5V. TJ = TA.
PARAMETER
TEST CONDITIONS
MIN TYP MAX UNITS
UCC381-5 Fixed 5V, 1A Family
Output Voltage
TJ = 25°C
4.925 5 5.075 V
Over Temperature
4.875
5.125 V
Line Regulation
Load Regulation
VIN = 5.15V to 9V
IOUT = 0mA to 1A
1 3 mV
2 5 mV
Drop Out Voltage, VIN – VOUT
Peak Current Limit
IOUT = 1A, VOUT = 4.85V, TA < 85°C
IOUT = 200mA, VOUT = 4.85V, TA < 85°C
VOUT = 0V
0.5 0.6
V
100 200 mV
2 3.5 A
Overcurrent Threshold
1 1.8 A
Current Limit Duty Cycle
Overcurrent Time Out, TON
Quiescent Current
VOUT = 0V
VOUT = 0V
3 5%
400 750 1600 µs
400 650 µA
Quiescent Current in Shutdown
Shutdown Threshold
Reverse Leakage Current
VIN = 9V
At CT Input
1V < VIN < VOUT, VOUT < 5.1V, at VOUT
10
0.25 0.65
25
75
µA
V
µA
UVLO Threshold
VIN where VOUT passes current
2.5 2.8 3.0
V
2