Texas Instruments UCC383T-5, UCC383T-3, UCC383TDTR-ADJ, UCC383TDTR-3, UCC383TD-ADJ Datasheet
...
Low Dropout 3 Ampere Linear Regulator Family
UCC283-3/-5/-ADJ
UCC383-3/-5/-ADJ
FEATURES
• Precision Positive Series Pass
Voltage Regulation
• 0.45V Dropout at 3A
• 50mV Dropout at 10mA
• Quiescent Current Under
650µA Irrespective of Load
• Adjustable (5 Lead) Output
Voltage Version
• Fixed (3 Lead) Versions for
3.3V and 5V Outputs
• Logic Shutdown Capability
• Short Circuit Power Limit of
3% •V
• Low V
Leakage
• Thermal Shutdown
• I
IN
SHORT
to VINReverse
OUT
DESCRIPTION
The UCC283-3/-5/-ADJ family of positive linear series pass regulators are tailored
for low drop out applications where low quiescent power is important. Fabricated
with a BiCMOS technology ideally suited for low input to output differential applications, the UCC283-5 will pass 3A while requiring only 0.45V of typical input voltage
headroom (guaranteed 0.6V dropout). These regulators include reverse voltage
sensing that prevents current in the reverse direction. Quiescent current is always
less than 650µA. These devices have been internally compensated in such a manner that the need for a minimum output capacitor has been eliminated.
UCC283-3 and UCC283-5 versions are in 3 lead packages and have preset outputs
at 3.3V and 5.0V respectively. The output voltage is regulated to 1.5% at room temperature. The UCC283-ADJ version, in a 5 lead package, regulates the output voltage programmed by an external resistor ratio.
Short circuit current is internally limited. The device responds to a sustained overcurrent condition by turning off after a T
riod, T
at the T
, that is 32 times the TONdelay. The device then begins pulsing on and off
OFF
/(TON+T
ON
) duty cycle of 3%. This drastically reduces the power dissipa-
OFF
tion during short circuit and means heat sinks need only accommodate normal operation. On the 3 leaded versions of the device T
adjustable 5 leaded versions an external capacitor sets the on time — the off time
is always 32 times T
. The external timing control pin, CT, on the five leaded ver-
ON
sions also serves as a shutdown input when pulled low.
delay. The device then stays off for a pe-
ON
is fixed at 750µs, on the
ON
BLOCK DIAGRAM
Internal power dissipation is further controlled with thermal overload protection circuitry. Thermal shutdown occurs if the junction temperature exceeds 165°C. The
chip will remain off until the temperature has dropped 20°C.
The UCC283 series is specified for operation over the industrial range of −40°Cto
+85°C, and the UCC383 series is specified from 0°C to +70°C. These devices are
available in 3 and 5 pin TO-220 and TO-263 power packages.
SLUS215 - OCTOBER 1998
UDG-98133
UCC283-3/-5/-ADJ
UCC383-3/-5/-ADJ
ABSOLUTE MAXIMUM RATINGS
VIN .........................................................9V
CT.......................................−0.3 to 3V
ADJ......................................−0.3 to 9V
Storage Temperature ...................−65°C to +150°C
Junction Temperature...................−55°C to +150°C
Lead Temperature (Soldering, 10 sec.) .............+300°C
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.
TO-220-3 (Front View)
T Package
CONNECTION DIAGRAMS
TO-263-3 (Front View)
TD Package
See Note 1
TO-220-5 (Front View)
T Package
See Note 1See Note 1
TO-263-5 (Front View)
TD Package
Note 1: Tab = GND
ELECTRICAL CHARACTERISTICS: Unless otherwise stated, these specifications hold for T
UCC383-X series, −40°C to +85°C for the UCC283-X, V
283-ADJ, V
= 6.5V, CT = 750pF, TJ=TA.
VIN
VIN=VVOUT
+ 1.5V, I
= 10mA, CIN=10µF, C
OUT
=0°Cto70°C for the
A
=22µF. For the
OUT
PARAMETER TEST CONDITIONS MIN TYP MAX UNITS
UCC283-5 Fixed 5V, 3A Family
Output Voltage TJ=25°C 4.925 5 5.075 V
Over Temperature 4.875 5.125 V
Line Regulation V
Load Regulation I
Dropout Voltage, V
DROPOUT=VVIN
− V
VOUT
Peak Current Limit V
= 5.15V to 9V 2 10 mV
VIN
= 10mA to 3A 10 20 mV
OUT
I
= 3A, VOUT = 4.85V 0.4 0.6 V
OUT
I
= 1.5A, VOUT = 4.85V 0.2 0.45 V
OUT
I
= 10mA, VOUT = 4.85V 50 150 mV
OUT
= 0V 4 5 6.5 A
VOUT
Overcurrent Threshold 3 4 5.5 A
Current Limit Duty Cycle V
Overcurrent Time Out, T
ON
=0V 3 5 %
VOUT
V
= 0V 400 750 1400 µs
VOUT
Quiescent Current No load 400 650 µA
Reverse Leakage Current 0V < V
VIN<VVOUT
,
V
VOUT
≤ 5.1V, at V
VOUT
075mA
UVLO VIN where VOUT passes current 2.6 2.8 3 V
2
UCC283-3/-5/-ADJ
UCC383-3/-5/-ADJ
ELECTRICAL CHARACTERISTICS:
UCC383-X series, −40°C to +85°C for the UCC283-X, V
283-ADJ, V
= 6.5V, CT = 750pF, TJ=TA.
VIN
Unless otherwise stated, these specifications hold for TA=0°Cto70°C for the
VIN=VVOUT
+ 1.5V, I
= 10mA, CIN=10µF, C
OUT
=22µF. For the
OUT
PARAMETER TEST CONDITIONS MIN TYP MAX UNITS
UCC283-3 Fixed 3.3V, 3A Family
Output Voltage T
=25°C 3.25 3.3 3.35 V
J
Over Temperature 3.22 3.38 V
Line Regulation V
Load Regulation I
Dropout Voltage, V
DROPOUT=VVIN
-
V
VOUT
Peak Current Limit V
= 3.45V to 9V 2 7 mV
VIN
= 10mA to 3A 7 15 mV
OUT
I
= 3A, VOUT = 3.15V 0.5 1 V
OUT
= 1.5A, VOUT = 3.15V 0.25 0.6 V
I
OUT
I
= 10mA, VOUT = 3.15V 50 150 mV
OUT
= 0V 4 5 6.5 A
VOUT
Overcurrent Threshold 3 4 5.5 A
Current Limit Duty Cycle V
Overcurrent Time Out, TON V
=0V 3 5 %
VOUT
= 0V 400 750 1400 µs
VOUT
Quiescent Current No load 400 650 µA
Reverse Leakage Current 0V < V
VIN<VVOUT
,
≤ 3.35V, at V
VOUT
VOUT
075mA
V
UVLO VIN where VOUT passes current 2.6 2.8 3 V
UCC283-ADJ Adjustable Output, 3A Family
Regulating Voltage at ADJ Pin T
= 25°C 1.23 1.25 1.27 V
J
Over Temperature 1.22 1.28 V
Line Regulation, at ADJ Input V
Load Regulation, at ADJ Input I
Dropout Voltage, V
DROPOUT
= VIN − VOUT V
Peak Current Limit V
Overcurrent Threshold V
Current Limit Duty Cycle V
Overcurrent Time Out, T
ON
VIN=VVOUT
OUT
VIN
V
VIN
V
VIN
VOUT
VIN
VOUT
V
VOUT
Reverse Leakage Current 0V < V
= 10mA to 3A 2 5 mV
> 4V, I
> 3V, I
> 3V, I
= 6.5V 3 4 5.5 A
+ 150mV to 9V 1 3 mV
= 3A 0.4 0.6 V
OUT
= 1.5A 0.2 0.45 V
OUT
= 10mA 50 150 mV
OUT
= 0V, VIN = 6.5V 4 5 6.5 A
=0V 3 5 %
= 0V, CT = 1500pF 750 µs
V
VIN<VVOUT
,
VOUT
≤ 9V, at V
VOUT
0 100 mA
Bias current at ADJ Input 100 250 nA
Quiescent Current No load 400 650 µA
Shutdown Threshold At CT Input 0.25 0.45 V
Quiescent Current in Shutdown V
= 10V 40 75 µA
VIN
UVLO VIN where VOUT passes current 2.6 2.8 3 V
3
PIN DESCRIPTIONS
UCC283-3/-5/-ADJ
UCC383-3/-5/-ADJ
ADJ: Adjust pin for the UCC283-ADJ version only. Feed-
back pin for the linear regulator. Program the output voltage with R1 connected from ADJ to GND and R2
connected from VOUT to ADJ. Output voltage is given by:
=
.
R
1
VOUT
()
VR R
·+125 1 2
CT: Short circuit timing capacitor and shutdown input for
the UCC283-ADJ version. Pulling CT below 0.25V turns
off the regulator and places it in a low quiescent current
mode. A timing capacitor, C, from CT to GND programs
the duration of the pulsed short circuit on-time. On-time,
T
, is approximately given by:
ON
TON=
500
k·C
.
Table I. Package Information
Temperature
Range
2: –40°Cto+85°C T: TO-220 3: 3.3V
3: 0°Cto+70°C TD: TO-263 5: 5V
Package Output Voltage
ADJ: Adjustable
APPLICATION INFORMATION
Overview
The UCC383 family of low dropout linear (LDO) regulators provide a regulated output voltage for applications
with up to 3A of load current. The regulators feature a
low dropout voltage and short circuit protection, making
their use ideal for demanding high current applications
requiring fault protection.
Short Circuit Protection
The UCC383 provides unique short circuit protection
circuitry that reduces power dissipation during a fault.
When an overload situation is detected, the device
enters a pulsed mode of operation at 3% duty cycle
reducing the heat sink requirements during a fault. The
UCC383 has two current thresholds that determine its
behavior during a fault as shown in Figure 1.When the
regulator current exceeds the overcurrent threshold for
a period longer than T
period (T
) which is 32 times TON. During an overload,
OFF
the regulator actively limits the maximum current to the
peak current limit value. The peak current limit is
nominally 1 Amp greater than the overcurrent threshold.
The regulator will continue in pulsed mode until the fault
is cleared as illustrated in Figure 1.
Short Circuit Protection
A capacitive load on the regulator’s output will appear as
a short circuit during start-up. If the capacitance is too
, the UCC383 shuts off for a
ON
GND: Reference ground.
VIN: Input voltage, This pin must be bypassed with a low
ESL/ESR 1µF or larger capacitor to GND. VIN can range
from (VOUT + V
DROPOUT
) to 9V. If VIN is reduced to zero
while VOUT is held high, the reverse leakage from VOUT
to VIN is less than 75µA.
VOUT: Regulated output voltage. A bypass capacitor is
not required at VOUT, but may be desired for good transient response. The bypass capacitor must not exceed a
maximum value in order to insure the regulator can start.
ORDERING INFORMATION
large, the output voltage will not come into regulation
during the initial T
pulsed mode operation. The peak current limit, T
period, and load characteristics determine the maximum
value of output capacitor that can be charged. For a
constant current load the maximum output capacitance is
given as follows:
CII
OUT CL LOAD
=- ·
(max)
For worst case calculations the minimum values of on
time (T
) and peak current limit (ICL) should be used.
ON
The adjustable version allows the T
adjusted with a capacitor on the CT pin:
T C Farad
ON ADJ
()
T C Farads
ON
(sec)
m
For a resistive load (R
capacitor can be estimated from:
C
OUT
(max)
=
period and the UCC383 will enter
ON
T
()
,( )=·500 000 m
,
LOAD
T
l
LOAD
·
Rn
ON
Farads
V
OUT
ON
microseconds
()
m=·500 000
) the maximum output
ON
(sec)
æ
ç
ç
ç
ç
1
è
1
V
OUT
-
·
IR
CL LOAD
time to be
Farads
ö
÷
÷
÷
÷
ø
ON
(1)
(2)
(3)
4
APPLICATION INFORMATION (cont.)
UCC283-3/-5/-ADJ
UCC383-3/-5/-ADJ
Figure 1. UCC383 Short Circuit Timing
Dropout Performance
Referring to the Block Diagram, the dropout voltage of
the UCC383 is equal to the minimum voltage drop (V
V
) across the N-Channel MOSFET. The dropout
OUT
IN
voltage is dependent on operating conditions such as
load current, input and load voltages, as well as
temperature. The UCC383 achieves a low RDS
through the use of an internal charge-pump (V
PUMP
(ON)
) that
drives the MOSFET gate. Figure 2 depicts typical
dropout voltages versus load current for the 3.3V and 5V
Vout = 3V Vout = 3.3V Vout = 5V
0.5
0.4
(V)
0.3
OUT
–V
0.2
IN
V
0.1
0
1
1.5 2 2.5 3
Iout (A)
Figure 2. UCC383 Typical Dropout vs. Load Current
versions of the part, as well as the adjustable version
programmed to 3.0V.
Figure 3. depicts the typical dropout performance of the
to
adjustable version with various output voltages and load
currents.
Operating temperatures also effect the RDS
dropout voltage of the UCC383. Figure 4. graphs the
typical dropout for the 3.3V and 5V versions with a 3A
load over temperature.
Iout = 1A Iout = 1.5A Iout = 3A
0.8
0.7
0.6
(V)
0.5
OUT
0.4
–V
0.3
IN
V
0.2
0.1
0
3
Figure 3. Typical Dropout Voltage vs. I
3.5 4 4.5 5
V
OUT
(V)
OUT
and V
(ON)
and
VOUT
5
UCC283-3/-5/-ADJ
UCC383-3/-5/-ADJ
Voltage Programming and Shutdown Feature for
Adjustable Version
A typical application circuit based on the UCC383 adjustable version is shown in Figure 5. The output voltage is
externally programmed through a resistive divider at the
ADJ pin.
V
=·+
125 1
OUT
.
æ
ç
è
R
R
ö
2
÷
volts
ø
1
(4)
The maximum programmed output voltage is constrained
by the 9V absolute rating of the IC (this includes the
charge pump voltage) and its ability to enhance the NChannel MOSFET. Unless the load current is below the
3A rating of the device, output voltages above 7V are not
recommended. The minimum output voltage can be programmed down to 1.25V, however, the input voltage must
always be greater than the UVLO of the part.
The adjustable version includes a shutdown feature, limiting quiescent current to 40uA typical. The UCC383 is
shutdown by pulling the CT pin to below 0.25V. As shown
in Figure 4, a small logic level MOSFET or BJT transistor
in parallel with the timing capacitor can be driven with a
digital signal, putting the device in shutdown. If the CT
pin is not pulled low, the IC will internally pull up on the
pin enabling the regulator. The CT pin should not be
forced high, as this will interfere with the short circuit protection feature. Selection of the timing capacitor is explained in
Short Circuit Protection
.
Thermal Design
The Packing Information section of the data book contains reference material for the thermal ratings of various
packages. The section also includes an excellent article
Thermal Characteristics of Surface Mount Packages
, that
is the basis of the following discussion.
Thermal design for the UCC383 includes two modes of
operation, normal and pulsed mode. In normal operation, the linear regulator and heat sink must dissipate
power equal to the maximum forward voltage drop multiplied by the maximum load current. Assuming a constant
current load, the expected heat rise at the regulator’s
junction can be calculated as follows:
TP
()qqq=·+
RISE DISS jc ca
()
°C
Where theta, (θ) is thermal resistance and P
DISS
(5)
is the
power dissipated. The thermal resistance of both the
TO-220 and TO-263 packages (junction to case) is 3 degrees Celsius per Watt. In order to prevent the regulator
from going into thermal shutdown, the case to ambient
theta must keep the junction temperature below 150°C.
If the LDO is mounted on a 5 square inch pad of 1 ounce
copper, for example, the thermal resistance from junction
to ambient becomes 60 degrees Celsius per Watt. If a
lower thermal resistance is required by the application,
the device heat sinking would need to be improved.
The adjustable version can be used in applications requiring remote voltage sensing (i.e. monitoring a voltage
other than or not directly tied to the VOUT pin). This is
possible since the inverting input of the voltage amplifier
(see Block Diagram) is brought out to the ADJ pin.
Vout = 3.3v Vout = 5v
0.6
0.5
(mv)
OUT
0.4
–V
IN
0.3
V
0.2
-40
10 60
TEMPERATURE (°C)
Figure 4. Typical dropout voltage vs. case
temperature with a 3A load
0.5
0.4
0.3
0.2
0.1
IDD CURRENT(mAMPS)
0
0123
LOAD CURRENT (AMPS)
Figure 5. Typical application for the 5 pin adjustable
version.
6
UCC283-3/-5/-ADJ
UCC383-3/-5/-ADJ
When the UCC383 regulator is in pulsed mode due to an
overload or short circuit in the application, the maximum
average
power dissipation is calculated as follows:
T
PVVI
PULSE AVE IN OUT CL
_
()
–=··
ON
T
·33
ON
Watts
(6)
As seen in equation 6, the average power during a fault
is reduced dramatically by the duty cycle, allowing the
heat sink to be sized for normal operation. Although the
peak power in the regulator during the T
period can be
ON
significant, the thermal mass of the package will generally keep the junction temperature from rising unless the
T
period is increased to tens of milliseconds.
ON
Ripple Rejection
Even though the UCC383 family of linear regulators are
not optimized for fast transient applications (Refer to
UC182 Fast LDO Linear Regulator), they do offer
significant power supply rejection at lower frequencies.
Figure 6 depicts ripple rejection performance in a typical
application. The performance can be improved with
additional filtering.
Figure 6. Typical supply current vs. load current.
UNITRODE CORPORATION
7 CONTINENTAL BLVD. • MERRIMACK, NH 03054
TEL. (603) 424-2410FAX(603) 424-3460
UDG-94093
Figure 7. Ripple rejection vs. frequency.
7
IMPORTANT NOTICE
T exas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue
any product or service without notice, and advise customers to obtain the latest version of relevant information
to verify, before placing orders, that information being relied on is current and complete. All products are sold
subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those
pertaining to warranty, patent infringement, and limitation of liability.
TI warrants performance of its semiconductor products to the specifications applicable at the time of sale in
accordance with TI’s standard warranty. Testing and other quality control techniques are utilized to the extent
TI deems necessary to support this warranty . Specific testing of all parameters of each device is not necessarily
performed, except those mandated by government requirements.
CERTAIN APPLICATIONS USING SEMICONDUCTOR PRODUCTS MAY INVOLVE POTENTIAL RISKS OF
DEATH, PERSONAL INJURY, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE (“CRITICAL
APPLICATIONS”). TI SEMICONDUCTOR PRODUCTS ARE NOT DESIGNED, AUTHORIZED, OR
WARRANTED TO BE SUITABLE FOR USE IN LIFE-SUPPORT DEVICES OR SYSTEMS OR OTHER
CRITICAL APPLICA TIONS. INCLUSION OF TI PRODUCTS IN SUCH APPLICATIONS IS UNDERST OOD TO
BE FULLY AT THE CUSTOMER’S RISK.
In order to minimize risks associated with the customer’s applications, adequate design and operating
safeguards must be provided by the customer to minimize inherent or procedural hazards.
TI assumes no liability for applications assistance or customer product design. TI does not warrant or represent
that any license, either express or implied, is granted under any patent right, copyright, mask work right, or other
intellectual property right of TI covering or relating to any combination, machine, or process in which such
semiconductor products or services might be or are used. TI’s publication of information regarding any third
party’s products or services does not constitute TI’s approval, warranty or endorsement thereof.
Copyright 1999, Texas Instruments Incorporated
Loading...