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UCC283-3, UCC283-5, UCC283-ADJ, UCC383-3, UCC383-5, UCC383-ADJ LOW DROPOUT 3 A LINEAR REGULATOR FAMILY
SLUS215A - OCTOBER 1998 - REVISED JUNE 2000
D Precision Positive Linear Series Pass D D D D D D D D D
Voltage Regulation 0.45 V Dropout at 3 A 50 mV Dropout at 10 mA Quiescent Current Under 650 A Irrespective of Load Adjustable (5-Lead) Output Voltage Version Fixed (3-Lead) Versions for 3.3-V and 5-V Outputs Logic Shutdown Capability Short-Circuit Power Limit of (3% x VIN x ISHORT) Low VOUT to VIN Reverse Leakage Thermal Shutdown
TO-263-5 TD PACKAGE (FRONT VIEW)
5 4 3 2 1 VOUT ADJ GND CT VIN
TO-263-3 TD PACKAGE (FRONT VIEW)
3 2 1 VOUT GND VIN
TO-220-5 T PACKAGE (FRONT VIEW)
5 4 3 2 1 VOUT ADJ GND CT VIN
+
TO-220-3 T PACKAGE (FRONT VIEW)
3 2 1 VOUT GND VIN
description
The UCC283-3/-5/-ADJ family of positive linear series pass voltage 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 passes 3 A while requiring only 0.45 V of typical input voltage headroom (ensured 0.6-V dropout).
+
These regulators include reverse voltage sensing that prevents current in the reverse direction. Quiescent current is always less than 650 A. These devices have been internally compensated in such a way 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 3.3 V and 5.0 V 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 tON time delay. The device then stays off for a period, 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 dissipation during short-circuit and means heat sinks need only accommodate normal operation. On the 3-leaded versions of the device tON is fixed at 750 s, on the adjustable 5-leaded versions an external capacitor sets the on time. The off time is always 32 x tON. The external timing control pin, CT, on the 5-leaded versions also serves as a shutdown input when pulled low. Internal power dissipation is further controlled with thermal overload protection circuitry. Thermal shutdown occurs if the junction temperature exceeds 165C. The chip remains off until the temperature has dropped 20C. The UCC283 series is specified for operation over the industrial range of -40C to 85C, and the UCC383 series is specified from 0C to 70C. These devices are available in 3- and 5-pin TO-220 and TO-263 power packages.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters.
Copyright (c) 2000, Texas Instruments Incorporated
POST OFFICE BOX 655303
* DALLAS, TEXAS 75265
1
UCC283-3, UCC283-5, UCC283-ADJ, UCC383-3, UCC383-5, UCC383-ADJ LOW DROPOUT 3 A LINEAR REGULATOR FAMILY
SLUS215A - OCTOBER 1998 - REVISED JUNE 2000
AVAILABLE OPTIONS TA OUTPUT VOLTAGE (V) MIN 3.22 -40C to 85C 40 C 85 C 4.875 3.22 0C to 70C 0C o 0C 4.875 TYP 3.3 5.00 ADJ 3.3 5.00 ADJ 3.58 5.125 MAX 3.58 5.125 UCC283TD-3 UCC283TD-5 -- UCC383TD-3 UCC383TD-5 -- PACKAGE DEVICES TO-263-3 TD -- -- UCC283TD-ADJ -- -- UCC383TD-ADJ UCC283T-3 UCC283T-5 -- UCC383T-3 UCC383T-5 -- TO-263-5 TO-220-3 T -- -- UCC283T-ADJ -- -- UCC383T-ADJ TO-220-5
All package types are available taped and reeled. Add TR suffix to device type (e.g. UCC283TD-3TR) to order quantities of 3000 devices per reel.
functional block diagram
VIN
*5 LEADED VERSION ONLY (ADJ) VPUMP CURRENT LIMIT ADJ* 4 A/ 7 A CURRENT REFERENCE + + 0.65 V 1.25 V R1 GND R2 VOUT
SD/CT*
3% DUTY CYCLE CURRENT LIMIT TIMER REVERSE VOLTAGE SENSE UVLO THERMAL SHUTDOWN UCC283-ADJ UCC283-3 UCC283-5
R2 0 82k 150k
R1 OPEN 50k 50k
UDG-98133
2
POST OFFICE BOX 655303
* DALLAS, TEXAS 75265
UCC283-3, UCC283-5, UCC283-ADJ, UCC383-3, UCC383-5, UCC383-ADJ LOW DROPOUT 3 A LINEAR REGULATOR FAMILY
SLUS215A - OCTOBER 1998 - REVISED JUNE 2000
electrical characteristics TA = 0C to 70C for the UCC383-x series, TA = -40C to 85C for the UCC283-x, VVIN = VVOUT + 1.5 V, IOUT = 10 mA, CIN = 10 F, COUT = 22 F. For the UCC283-ADJ, VVIN = 6.5 V, VOUT = 5.0 V, CT = 750 pF, TJ = TA unless otherwise stated
PARAMETER UCC283-5 Fixed 5 V, 3 A Family Output voltage Line regulation Load regulation TJ = 25C Over temperature VVIN = 5.15 V to 9 V IOUT = 10 mA to 3 A IOUT = 3 A, IOUT = 1.5 A, IOUT = 10 mA, VVOUT = 0 V VVOUT = 0 V VVOUT = 0 V No load 1 V < VVIN < VVOUT, VVOUT 5.1 V, at VVOUT VIN where VOUT passes current TJ = 25C Over temperature VVIN = 3.45 V to 9 V IOUT = 10 mA to 3 A IOUT = 3A, IOUT = 1.5A, IOUT = 10mA, VVOUT = 0 V VVOUT = 0 V VVOUT = 0 V No load 1 V < VVIN < VVOUT, VVOUT 3.35 V at VVOUT VIN where VOUT passes current VOUT = 3.15 V VOUT = 3.15 V VOUT = 3.15 V 4 3 400 VOUT = 4.85 V VOUT = 4.85 V VOUT = 4.85 V 4 3 400 4.925 4.875 2 10 0.4 0.2 50 7 4 3% 750 400 30 2.5 3.25 3.22 2 7 0.5 0.25 50 7 4 3% 750 400 30 2.5 2.8 2.8 3.3 5 5.075 5.125 10 20 0.6 0.45 150 10 5.5 5% 1400 650 75 3 3.35 3.38 7 15 1 0.6 150 10 5.5 5% 1400 650 75 3 s A A V s A A V V V mV mV V V mV A A V V mV mV V V mV A A TEST CONDITIONS MIN TYP MAX UNITS
Dro out Dropout voltage, VDROPOUT = VVIN - VVOUT Peak current limit Overcurrent threshold Current limit duty cycle Overcurrent time out, tON Quiescent current Reverse leakage current Undervoltage lockout UCC283-3 Fixed 3.3 V, 3 A Family Output voltage Line regulation voltage Load regulation voltage
Dro out Dropout voltage, VDROPOUT = VVIN - VVOUT Peak current limit Overcurrent threshold Current limit duty cycle Overcurrent time out, tON Quiescent current Reverse leakage current Undervoltage lockout
POST OFFICE BOX 655303
* DALLAS, TEXAS 75265
3
UCC283-3, UCC283-5, UCC283-ADJ, UCC383-3, UCC383-5, UCC383-ADJ LOW DROPOUT 3 A LINEAR REGULATOR FAMILY
SLUS215A - OCTOBER 1998 - REVISED JUNE 2000
electrical characteristics TA = 0C to 70C for the UCC383-x series, TA = -40C to 85C for the UCC283-x, VVIN = VVOUT + 1.5 V, IOUT = 10 mA, CIN = 10 F, COUT = 22 F. For the UCC283-ADJ, VVIN = 6.5 V, VOUT = 5.0 V, CT = 750 pF, TJ = TA unless otherwise stated
PARAMETER UCC283-ADJ Adjustable Output, 3 A Family TJ = 25C Regulating voltage at ADJ pin Line regulation voltage, at ADJ input Load regulation voltage, at ADJ input Over temperature VVIN = VVOUT + 150 mV to 9 V IOUT = 10 mA to 3 A VOUT = 4.85 V, VOUT = 4.85 V, VOUT = 4.85 V, VVOUT = 0 V VVOUT = 0 V VVOUT = 0 V 1 V < VVIN < VVOUT VVOUT 9 V, at VVOUT No load At CT input VVIN = 9 V VIN where VOUT passes current 0.25 2.5 IOUT = 3 A IOUT = 1.5 A IOUT = 10 mA 4 3 300 1.23 1.22 1 2 0.4 0.2 50 7 4 3 575 30 20 400 0.65 40 2.8 75 3 1.25 1.27 1.28 3 5 0.6 0.45 150 10 5.5 5 1200 100 250 650 V V mV mV V V mV A A % s A nA A V A V TEST CONDITIONS MIN TYP MAX UNITS
Dro out Dropout voltage, VDROPOUT = VIN - VOUT Peak current limit Overcurrent threshold Current limit duty cycle Overcurrent time out, tON Reverse leakage current Bias current at ADJ input Quiescent current Shutdown threshold Quiescent current in shutdown UVLO
absolute maximum ratings over operating free-air temperature (unless otherwise noted)
Input voltage VIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 V CT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 V to 3 V ADJ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 V to 9 V Storage Temperature, Tstg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -65C to 150C Junction Temperature, TJ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -55C to 150C Lead Temperature (soldering, 10 seconds) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300C
Stresses beyond those listed under "absolute maximum ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under "recommended operating conditions" is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
4
POST OFFICE BOX 655303
* DALLAS, TEXAS 75265
UCC283-3, UCC283-5, UCC283-ADJ, UCC383-3, UCC383-5, UCC383-ADJ LOW DROPOUT 3 A LINEAR REGULATOR FAMILY
SLUS215A - OCTOBER 1998 - REVISED JUNE 2000
pin descriptions
ADJ: Adjust pin for the UCC283-ADJ version only. Feedback 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: V OUT + 1.25 V (R1 ) R2) R1
CT: Short-circuit timing capacitor and shutdown input for the UCC283-ADJ version. Pulling CT below 0.25 V 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, tON, is approximately given by: t ON + 750 k C
GND: Reference ground. VIN: Input voltage, This pin must be bypassed with a low ESL/ESR 1-F or larger capacitor to GND. VIN can range from (VOUT + VDROPOUT) to 9 V. If VIN is reduced to zero while VOUT is held high, the reverse leakage from VOUT to VIN is less than 75A. 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.
APPLICATION INFORMATION overview
The UCC383 family of low dropout linear (LDO) regulators provide a regulated output voltage for applications with up to 3 A 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 tON, the UCC383 shuts off for a period (tOFF) which is 32 x tON. During an overload, the regulator actively limits the maximum current to the peak current limit value. The peak current limit is nominally 3 A greater than the overcurrent threshold. The regulator continues in pulsed mode until the fault is cleared as illustrated in Figure 1.
POST OFFICE BOX 655303
* DALLAS, TEXAS 75265
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UCC283-3, UCC283-5, UCC283-ADJ, UCC383-3, UCC383-5, UCC383-ADJ LOW DROPOUT 3 A LINEAR REGULATOR FAMILY
SLUS215A - OCTOBER 1998 - REVISED JUNE 2000
APPLICATION INFORMATION
PEAK CURRENT LIMIT OVER- CURRENT THRESHOLD IO (NOM) OVERLOAD
OUTPUT CURRENT
VO (NOM) ROLCL I OUTPUT VOLTAGE TON 32 TON TON 32 TON TON 32 TON
Figure 1. UCC383 Short-Circuit Timing A capacitive load on the regulator's output appears as a short-circuit during start-up. If the capacitance is too large, the output voltage does not come into regulation during the initial tON period and the UCC383 enters pulsed mode operation. The peak current limit, tON 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: C OUT(max) +I CL *I t LOAD V ON Farads (1)
OUT
For worst case calculations, the minimum values of on time (tON) and peak current limit (ICL) should be used. The adjustable version allows the tON time to be adjusted with a capacitor on the CT pin: t ON(adj) + 750, 000 C (m Farad) microseconds (2)
For a resistive load (RLOAD) the maximum output capacitor can be estimated from: t C OUT(max) + R LOAD ON(sec) 1 VOUT R CL LOAD Farads
n 1* I
(3)
6
POST OFFICE BOX 655303
* DALLAS, TEXAS 75265
UCC283-3, UCC283-5, UCC283-ADJ, UCC383-3, UCC383-5, UCC383-ADJ LOW DROPOUT 3 A LINEAR REGULATOR FAMILY
SLUS215A - OCTOBER 1998 - REVISED JUNE 2000
APPLICATION INFORMATION dropout performance
Referring to the Block Diagram, the dropout voltage of the UCC383 is equal to the minimum voltage drop (VIN to VOUT) across the N-channel MOSFET. The dropout voltage is dependent on operating conditions such as load current, input and load voltages, as well as temperature. The UCC383 achieves a low Rds(on) through the use of an internal charge-pump (VPUMP) that drives the MOSFET gate. Figure 2 depicts typical dropout voltages versus load current for the 3.3-V and 5-V versions of the part, as well as the adjustable version programmed to 3.0 V. Figure 3 depicts the typical dropout performance of the adjustable version with various output voltages and load currents. Operating temperatures also affect the Rds(on) and dropout voltage of the UCC383. Figure 4 graphs the typical dropout for the 3.3-V and 5-V versions with a 3-A load over temperature.
TYPICAL DROPOUT VOLTAGE vs. LOAD CURRENT 0.5 VOUT = 3.3 V 0.4 VIN-VOUT (V) 0.6 0.3 0.2 0.1 0 1 1.5 2 IOUT (A) 2.5 3 VOUT = 3 V VOUT = 5 V VIN-VOUT (V) 0.5 0.4 0.3 0.2 0.1 0 3 3.5 I OUT= 1 A 4 VOUT (V) 4.5 5 I OUT= 1.5 A I OUT= 3 A 0.8 0.7 TYPICAL DROPOUT VOLTAGE vs. IOUT AND VOUT
Figure 2
Figure 3
POST OFFICE BOX 655303
* DALLAS, TEXAS 75265
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UCC283-3, UCC283-5, UCC283-ADJ, UCC383-3, UCC383-5, UCC383-ADJ LOW DROPOUT 3 A LINEAR REGULATOR FAMILY
SLUS215A - OCTOBER 1998 - REVISED JUNE 2000
APPLICATION INFORMATION 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.
TYPICAL DROPOUT VOLTAGE vs. CASE TEMPERATURE WITH A 3-A LOAD
0.6
VIN - VOUT (V)
0.5
V OUT = 3.3 V
0.4 V OUT = 5 V 0.3
0.2 -40 10 Temperature ( C) 60
Figure 4
V
OUT
+ 1.25
1 ) R2 Volts R1
(4)
The maximum programmed output voltage is constrained by the 9-V absolute rating of the IC (this includes the charge pump voltage) and its ability to enhance the N-channel MOSFET. Unless the load current is below the 3-A rating of the device, output voltages above 7 V are not recommended. The minimum output voltage can be programmed down to 1.25 V. 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 40 A typical. The UCC383 is shut down by pulling the CT pin to below 0.25 V. As shown in Figure 5, 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 internally pulls up the pin enabling the regulator. The CT pin should not be forced high, as this interferes with the short-circuit-protection feature. Selection of the timing capacitor is explained in Short-Circuit-Protection. 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 error-voltage amplifier (see Block Diagram) is brought out to the ADJ pin.
8
POST OFFICE BOX 655303
* DALLAS, TEXAS 75265
UCC283-3, UCC283-5, UCC283-ADJ, UCC383-3, UCC383-5, UCC383-ADJ LOW DROPOUT 3 A LINEAR REGULATOR FAMILY
SLUS215A - OCTOBER 1998 - REVISED JUNE 2000
APPLICATION INFORMATION thermal design
The Package Information section of the Power Supply Control Products Data Book, Volume 3 (Literature No. SLUD003) 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 family of linear regulators 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: t (q) + P RISE DISS q ) q ca jc C (5)
Where theta, () is thermal resistance and PDISS is the power dissipated. The thermal resistance of both the TO-220 and TO-263 packages (junction to case) is 3C per Watt. In order to prevent the regulator from going into thermal shutdown, the case to ambient theta must keep the junction temperature below 150C. 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 60C per Watt. If a lower thermal resistance is required by the application, the device heat sinking would need to be improved. 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: P PULSE(avg) +V IN *V t OUT I CL 33 ON Watts t ON
(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 tON period can be significant, the thermal mass of the package generally keeps the junction temperature from rising unless the tON period is increased to tens of milliseconds.
ripple rejection
Even though the UCC383 family of linear regulators are not optimized for fast transient applications (Refer to the 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.
POST OFFICE BOX 655303
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UCC283-3, UCC283-5, UCC283-ADJ, UCC383-3, UCC383-5, UCC383-ADJ LOW DROPOUT 3 A LINEAR REGULATOR FAMILY
SLUS215A - OCTOBER 1998 - REVISED JUNE 2000
APPLICATION INFORMATION
UCC383-ADJ VINPUT 10F R2 1 VIN VOUT 5 10F RLOAD
2 CT SHUTDOWN GND 3
ADJ
4 R1
Figure 5. Typical Application for 5-Pin Adjustable Version
Figure 6. Ripple Rejection vs. Frequency
10
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IMPORTANT NOTICE Texas 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 acknowledgment, 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. Customers are responsible for their applications using TI components. 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 (c) 2000, Texas Instruments Incorporated

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