R EG
103
REG
REG103
103
REG
103
SBVS010D – JANUARY 2000 – REVISED SEPTEMBER 2005
DMOS
500mA Low-Dropout Regulator
FEATURES
DESCRIPTION
● NEW DMOS TOPOLOGY:
Ultra Low Dropout Voltage:
115mV Typ at 500mA and 3.3V Output
Output Capacitor NOT Required for Stability
● FAST TRANSIENT RESPONSE
● VERY LOW NOISE: 33µVrms
● HIGH ACCURACY: ±2% max
● HIGH EFFICIENCY:
IGND = 1mA at IOUT = 500mA
Not Enabled: IGND = 0.5µA
● 2.5V, 2.7V, 3.0V, 3.3V, 5.0V, AND ADJUSTABLE
OUTPUT VERSIONS
● FOLDBACK CURRENT LIMIT
● THERMAL PROTECTION
● OUTPUT VOLTAGE ERROR INDICATOR(1)
● SMALL SURFACE-MOUNT PACKAGES:
SOT223-5, DDPAK-5, SO-8
The REG103 is a family of low-noise, low-dropout, linear
regulators with low ground pin current. Its new DMOS
topology provides significant improvement over previous
designs, including low-dropout voltage (only 115mV typ at
full load), and better transient performance. In addition, no
output capacitor is required for stability, unlike conventional
low-dropout regulators that are difficult to compensate and
require expensive low ESR capacitors greater than 1µF.
Typical ground pin current is only 1mA (at IOUT = 500mA)
and drops to 0.5µA in not enabled mode. Unlike regulators
with PNP pass devices, quiescent current remains relatively
constant over load variations and under dropout conditions.
The REG103 has very low output noise (typically 33µVrms
for VOUT = 3.3V with CNR = 0.01µF), making it ideal for use
in portable communications equipment. On-chip trimming
results in high output voltage accuracy. Accuracy is maintained over temperature, line, and load variations. Key
parameters are tested over the specified temperature range
(–40°C to +85°C).
The SO-8 version of the REG103 has an ERROR pin that
provides a power good flag, indicating the regulator is in
regulation. The REG103 is well protected—internal circuitry provides a current limit that protects the load from
damage. Thermal protection circuitry keeps the chip from
being damaged by excessive temperature. In addition to the
SO-8 package, the REG103 is also available in the DDPAK
and the SOT223-5.
APPLICATIONS
●
●
●
●
●
●
PORTABLE COMMUNICATION DEVICES
BATTERY-POWERED EQUIPMENT
PERSONAL DIGITAL ASSISTANTS
MODEMS
BAR-CODE SCANNERS
BACKUP POWER SUPPLIES
ENABLE
ERROR(1)
ENABLE
VOUT
VIN
+
0.1µF
NR
REG103
(Fixed Voltage
Versions)
+
COUT
(2)
ERROR1)
VIN
VOUT
+
0.1µF
REG103-A
R1
+
COUT(2)
Adj
Gnd
Gnd
R2
NR = Noise Reduction
NOTE: (1) SO-8 Package Only. (2) Optional.
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.
All trademarks are the property of their respective owners.
Copyright © 2000-2005, Texas Instruments Incorporated
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.
www.ti.com
ABSOLUTE MAXIMUM RATINGS(1)
Supply Input Voltage, VIN ....................................................... –0.3V to 16V
Enable Input Voltage, VEN ....................................................... –0.3V to VIN
Feedback Voltage, VFB ........................................................ –0.3V to 6.0V
NR Pin Voltage, VNR ............................................................. –0.3V to 6.0V
Error Flag Output ..................................................................... –0.3V to 6V
Error Flag Current ............................................................................... 2mA
Output Short-Circuit Duration ...................................................... Indefinite
Operating Temperature Range ....................................... –55°C to +125°C
Storage Temperature Range .......................................... –65°C to +150°C
Junction Temperature ..................................................... –55°C to +150°C
Lead Temperature (soldering, 3s, SO-8, SOT, and DDPAK) ........ +240°C
ESD Rating: HBM (VOUT to GND) ..................................................... 1.5kV
HBM (All other pins) ........................................................ 2kV
CDM .............................................................................. 500V
ELECTROSTATIC
DISCHARGE SENSITIVITY
This integrated circuit can be damaged by ESD. Texas
Instruments recommends that all integrated circuits be handled
with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits
may be more susceptible to damage because very small
parametric changes could cause the device not to meet its
published specifications.
NOTE: (1) Stresses above these ratings may cause permanent damage.
Exposure to absolute maximum conditions for extended periods may degrade
device reliability.
PACKAGE/ORDERING INFORMATION(1)
PRODUCT
VOUT
REG103xx-yyyy/zzz
XX is package designator.
YYYY is typical output voltage (5 = 5.0V, 2.85 = 2.85V, A = Adjustable).
ZZZ is package quantity.
(1) For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI website at www.ti.com.
PIN CONFIGURATIONS
Top View
SOT223-5
SO-8
DDPAK-5
Tab is GND
1 2 3 4 5
VOUT
1
8
VIN
VOUT
2
7
VIN
NR/Adjust(1)
3
6
ERROR
GND
4
5
ENABLE
Tab is GND
1
VO
GND
NR/Adjust(1)
VIN
3
VIN
ENABLE
(F Package)
2
VOUT
(U Package)
4
5
GND
ENABLE
NR/Adjust(1)
(G Package)
NOTE: (1) For REG103A-A: voltage setting resistor pin.
All other models: noise reduction capacitor pin.
2
REG103
SBVS010D
ELECTRICAL CHARACTERISTICS
Boldface limits apply over the specified temperature range, TJ = –40°C to +85°C.
At TJ = +25°C, VIN = VOUT + 1V (VOUT = 3.0V for REG103-A), VENABLE = 2V, IOUT = 10mA, CNR = 0.01µF, and COUT = 0.1µF(1), unless otherwise noted.
REG103GA, UA, FA
PARAMETER
OUTPUT VOLTAGE
Output Voltage Range
REG103-2.5
REG103-2.7
REG103-3.0
REG103-3.3
REG103-5
REG103-A
Reference Voltage
Adjust Pin Current
Accuracy
TJ = –40°C to +85°C
vs Temperature
vs Line and Load
TJ = –40°C to +85°C
DC DROPOUT VOLTAGE(2, 3)
For all models except 5V
For 5V model
For all models except 5V
TJ = –40°C to +85°C
For 5V models
TJ = –40°C to +85°C
VOLTAGE NOISE
f = 10Hz to 100kHz
Without CNR (all models)
With CNR (all fixed voltage models)
OUTPUT CURRENT
Current Limit(4)
TJ = –40°C to +85°C
CONDITION
MIN
2.5
2.7
3.0
3.3
5
dVOUT/dT
VDROP
1.295
0.2
±0.5
TJ = –40°C to +85°C
IOUT = 10mA to 500mA, VIN = (VOUT + 0.7V) to 15V
VIN = (VOUT + 0.9V) to 15V
70
±0.5
IOUT = 10mA
IOUT = 500mA
IOUT = 500mA
IOUT = 500mA
3
115
160
IOUT = 500mA
CNR = 0, COUT = 0
CNR = 0.01µF, COUT = 10µF
25
200
250
230
mV
mV
mV
mV
280
mV
±2.5
µVrms
µVrms
30µVrms/V • VOUT
10µVrms/V • VOUT
ICL
550
500
700
950
1000
65
VENABLE
IENABLE
2
–0.2
VENABLE = 2V to VIN, VIN = 2.1V to
VENABLE = 0V to 0.5V
6.5(5)
1
2
50
1.5
VIN = VERROR = VOUT + 1V
Sinking 500µA
0.1
0.2
IGND
IOUT = 10mA
IOUT = 500mA
VENABLE ≤ 0.5V
0.5
1
0.5
mA
mA
dB
VIN
0.5
100
100
V
V
nA
nA
µs
ms
10
0.4
µA
V
°C
°C
150
130
ENABLE Pin LOW
TEMPERATURE RANGE
Specified Range
Operating Range
Storage Range
Thermal Resistance
DDPAK-5 Surface-Mount
SO-8 Surface-Mount
SOT223-5 Surface-Mount
±3.5
1
±2
±2.8
Vn
THERMAL SHUTDOWN
Junction Temperature
Shutdown
Reset from Shutdown
INPUT VOLTAGE
Operating Input Voltage Range(7)
Specified Input Voltage Range
TJ = –40°C to +85°C
UNITS
V
V
V
V
V
V
V
µA
%
%
ppm/°C
%
%
5.5
VREF
VREF
IADJ
ERROR FLAG(6)
Current, Logic HIGH (open drain)—Normal Operation
Voltage, Logic LOW—On Error
GROUND PIN CURRENT
Ground Pin Current
MAX
VOUT
RIPPLE REJECTION
f = 120Hz
ENABLE CONTROL
VENABLE HIGH (output enabled)
VENABLE LOW (output disabled)
IENABLE HIGH (output enabled)
IENABLE LOW (output disabled)
Output Disable Time
Output Enable Soft Start Time
TYP
0.7
1.3
mA
mA
µA
2.1
VOUT + 0.7
VOUT + 0.9
15
15
15
V
V
V
–40
–55
–65
+85
+125
+150
°C
°C
°C
VIN
VIN > 2.7V
VIN > 2.9V
TJ
θJC
θJA
θJC
Junction-to-Case
Junction-to-Ambient
Junction-to-Case
4
150
15
°C/W
°C/W
°C/W
NOTES: (1) The REG103 does not require a minimum output capacitor for stability. However, transient response can be improved with proper capacitor selection.
(2) Dropout voltage is defined as the input voltage minus the output voltage that produces a 2% change in the output voltage from the value at VIN = VOUT + 1V at
fixed load.
(3) Not applicable for VOUT less than 2.7V.
(4) Current limit is the output current that produces a 10% change in output voltage from VIN = VOUT + 1V and IOUT = 10mA.
(5) For VIN > 6.5V, see typical characteristic VENABLE vs IENABLE.
(6) Logic low indicates out-of-regulation condition by approximately 10%, or thermal shutdown.
(7) The REG103 no longer regulates when VIN < VOUT + VDROP (MAX). In drop-out or when the input voltage is between 2.7V and 2.1V, the impedance from VIN to
VOUT is typically less than 1Ω at TJ = +25°C. See typical characteristic.
REG103
SBVS010D
3
TYPICAL CHARACTERISTICS
For all models, at TJ = +25°C and VENABLE = 2V, unless otherwise noted.
OUTPUT VOLTAGE CHANGE vs IOUT
(VIN = VOUT + 1V, Output Voltage % Change
Referred to IOUT = 10mA at +25°C)
DC DROPOUT VOLTAGE vs OUTPUT CURRENT
180
0.5
DC Dropout Voltage (mV)
Output Voltage Change (%)
160
0
–0.5
–1.0
= –55°C
= +25°C
= +125°C
100
80
60
40
= –55°C
= +25°C
= +125°C
0
0
100
200
300
400
0
500
100
200
300
400
500
IOUT (mA)
Output Current (mA)
OUTPUT VOLTAGE CHANGE vs VIN
(Output Voltage % Change Referred
to VIN = VOUT + 1V at IOUT = 10mA)
OUTPUT VOLTAGE vs TEMPERATURE
(Output Voltage % Change Referred to
IOUT = 10mA at +25°C)
0.5
0.1
Output Voltage Change (%)
Output Voltage Change (%)
120
20
–1.5
0
–0.5
–1.0
= 10mA
= 100mA
= 500mA
–1.5
0
2
4
6
8
0.5
0
–0.5
= 10mA
= 100mA
= 500mA
–1
–1.5
–75
10
–50
–25
0
25
50
75
100
Input Voltage Above VOUT
Temperature (°C)
DC DROPOUT VOLTAGE vs TEMPERATURE
LINE REGULATION vs TEMPERATURE
(VIN = VOUT + 1V to VIN = 15V )
125
0.5
Output Voltage Change (%)
160
DC Dropout Voltage (mV)
140
120
= 10mA
= 100mA
= 500mA
80
40
0.4
0.3
0.2
0.1
= 10mA
= 100mA
0
–75
–50
–25
0
25
50
Temperature (°C)
4
75
100
125
0
–75
–50
–25
0
25
50
75
100
125
Temperature (°C)
REG103
SBVS010D
TYPICAL CHARACTERISTICS (Cont.)
For all models, at TJ = +25°C and VENABLE = 2V, unless otherwise noted.
COUT = 0
VOUT
50mV/div
200mV/div
200mV/div
REG103-3.3
VIN = 4.3V
LINE TRANSIENT RESPONSE
COUT = 10µF
VOUT
50mV/div
LOAD TRANSIENT RESPONSE
COUT = 0
COUT = 10µF
500mA
IOUT
VOUT
VOUT
6V
10mA
VIN
5V
10µs/div
50µs/div
VOUT
50mV/div
LINE TRANSIENT RESPONSE
VOUT
50mV/div
REG103-Adj.
VOUT = 3.3V, VIN = 4.3V, CFB = 0.01µF
COUT = 0
200mV/div
200mV/div
LOAD TRANSIENT RESPONSE
COUT = 10µF
500mA
IOUT
REG103-Adj.
VOUT = 3.3V, CFB = 0.01µF, IOUT = 100mA
VOUT
COUT = 10µF
VOUT
VIN
5V
10µs/div
50µs/div
LOAD REGULATION vs TEMPERATURE
(VIN = VOUT + 1V and 10mA < IOUT < 500mA)
OUTPUT NOISE DENSITY
10
0.4
Noise Density (µV/√Hz)
Output Voltage Change (%)
0.5
0.3
0.2
0.1
0
–75
1
CNR = 0
COUT = 0
0.1
CNR = 0.01µF
COUT = 10µF
0.01
–50
–25
0
25
50
Temperature (°C)
REG103
COUT = 0
6V
10mA
SBVS010D
REG103-3.3
Load = 100mA
75
100
125
10
100
1000
10000
100,000
Frequency (Hz)
5
TYPICAL CHARACTERISTICS (Cont.)
For all models, at TJ = +25°C and VENABLE = 2V, unless otherwise noted.
GROUND PIN CURRENT, NOT ENABLED
vs TEMPERATURE
GROUND PIN CURRENT vs TEMPERATURE
3
1.2
VENABLE = 0V
1.1
2.5
2
= 10mA
= 100mA
= 500mA
0.9
0.8
IGND (µA)
IGND (mA)
1
0.7
1.5
1
0.6
0.5
0.5
0.4
–75
–50
–25
0
25
50
75
100
0
–75
125
–50
–25
0
GROUND PIN CURRENT vs IOUT
50
75
100
125
IADJUST vs TEMPERATURE
1.2
0.28
1.1
0.26
Adjust Pin Current (µA)
REG103-A
1
IGND (mA)
25
Temperature (°C)
Temperature (°C)
0.9
0.8
0.7
0.6
0.24
0.22
0.20
0.18
0.16
0.5
0.4
1
10
100
1000
0.14
–60 –40 –20
IOUT (mA)
0
20
40
60
80
100 120
140
Temperature (°C)
CURRENT LIMIT vs TEMPERATURE
RIPPLE REJECTION vs FREQUENCY
70
730
720
60
Ripple Rejection (dB)
Current Limit (mA)
710
700
690
680
670
660
650
40
COUT = 0
VOUT = VOUT-NOMINAL • 0.90
VOUT = 1V
20
–50
–25
0
25
50
Temperature (°C)
6
COUT = 10µF
30
640
630
–75
50
75
100
125
10
100
1000
10000
100000
Frequency (Hz)
REG103
SBVS010D
TYPICAL CHARACTERISTICS (Cont.)
For all models, at TJ = +25°C and VENABLE = 2V, unless otherwise noted.
RIPPLE REJECTION vs IOUT
SOFT START
75
VRIPPLE = 3Vp-p, f = 120Hz
No Load
1V/div
Ripple Rejection (dB)
70
65
VOUT
RLOAD = 6.8Ω
60
55
50
45
VENABLE
2V
0
40
0
100
200
300
400
500
250µs/div
Load Current (mA)
OUTPUT VOLTAGE DRIFT HISTOGRAM
OUTPUT DISABLE TIME
45
40
RLOAD = 330
35
VOUT
Percent of Units (%)
1V/div
No Load
RLOAD = 6.8Ω
30
25
20
15
10
5
VENABLE
2V
0
0
40
10µs/div
45
50
55
60
65
70
75
80
85
90
VOUT Drift (ppm/°C)
OUTPUT VOLTAGE ACCURACY HISTOGRAM
60
Percent of Units (%)
50
40
30
20
10
0
–1 –0.8 –0.6 –0.4 –0.2
0
0.2 0.4
0.6 0.8
1
Error (%)
REG103
SBVS010D
7
BASIC OPERATION
The REG103 series is a family of LDO (Low Drop-Out)
linear regulators. The family includes five fixed output
versions (2.5V to 5.0V) and an adjustable output version. An
internal DMOS power device provides low dropout regulation with near constant ground pin current (largely independent of load and drop-out conditions) and very fast line and
load transient response. All versions include internal current
limit and thermal shutdown circuitry.
Figure 1 shows the basic circuit connections for the fixed
voltage models. Figure 2 gives the connections for the
adjustable output version (REG103A) and example resistor
values for some commonly used output voltages. Values for
other voltages can be calculated from the equation shown in
Figure 2. The SO-8 package provides two pins each for VIN
and VOUT. Both sets of pins MUST be used and connected
adjacent to the device.
ENABLE
VIN
In
ERROR
REG103
Gnd
0.1µF
VOUT
Out
NR
COUT
CNR
0.01µF
Optional
FIGURE 1. Fixed Voltage Nominal Circuit for REG103.
ENABLE
INTERNAL CURRENT LIMIT
The REG103 internal current limit has a typical value of
700mA. A fold-back feature limits the short-circuit current
to a typical short-circuit value of 40mA. This circuit will
protect the regulator from damage under all load conditions.
A typical characteristic of VOUT versus IOUT is given in
Figure 3a.
Care should be taken in high current applications to avoid
ground currents flowing in the circuit board traces causing
voltage drops between points on the circuit. If voltage drops
occur on the circuit board ground that causes the load ground
voltage to be much lower than the ground voltage seen by
the ground pin on the REG103, the foldback current may
approach zero and the REG103 may not start up. In these
types of applications, a large value resistor can be placed
between VIN and VOUT to help “boost” up the output of the
REG103 during start-up, see Figure 3b. The value for the
“boost” resistor should be chosen so that the current through
the “boost” resistor is less than the minimum load current:
RBOOST > (VIN – VOUT)/ILOAD. Typically, a good value for a
“boost” resistor is 5kΩ.
ERROR
5
VIN
None of the versions require an output capacitor for regulator stability. The REG103 will accept any output capacitor
type less than 1µF. For capacitance values larger than 1µF,
the effective ESR should be greater than 0.1Ω. This minimum ESR value includes parasitics such as printed circuit
board traces, solder joints, and sockets. A minimum 0.1µF
low ESR capacitor connected to the input supply voltage is
recommended.
6
8
1
7
2
REG103
3
0.1µF
VOUT
IADJ
4 Gnd
R1
CFB
0.01µF
EXAMPLE RESISTOR VALUES
R1 (Ω)(1)
R2 (Ω)(1)
1.295
Short
Open
2.5
12.1k
1.21k
13k
1.3k
3
16.9k
1.69k
13k
1.3k
3.3
20k
2.0k
13k
1.3k
5
37.4k
3.74k
13k
1.3k
VOUT (V)
COUT
Load
Adj
R2
Pin numbers for SO-8 package.
Optional
VOUT = (1 + R1/R2) • 1.295V
To reduce current through divider, increase resistor
values (see table at right).
NOTE: (1) Resistors are standard 1% values.
As the impedance of the resistor divider increases,
IADJ (~200nA) may introduce an error.
CFB improves noise and transient response.
FIGURE 2. Adjustable Voltage Circuit for REG103A.
8
REG103
SBVS010D
3.5
100
2.5
10
Enable Current (µA)
Output Voltage (V)
3
2
1.5
1
0.5
1
0.1
0.01
0
0
100
200
300
400
500
600
700
800
Output Current (mA)
0.001
0
2
4
6
(a) Foldback Current Limit of the REG103-3.3 at 25°C.
8
10
12
14
16
Enable Voltage
RBOOST
FIGURE 5. ENABLE Pin Current versus Applied Voltage.
VIN
VOUT
REG103
+
+
0.1µF
0.1µF(1)
Load
Gnd
(1) Optional.
(b) Foldback Current Boost Circuit.
FIGURE 3. Foldback Current Limit and Boost Circuit.
ENABLE
The ENABLE pin allows the regulator to be turned on and
off. This pin is active HIGH and compatible with standard
TTL-CMOS levels. Inputs below 0.5V (max) turn the regulator off and all circuitry is disabled. Under this condition,
ground pin current drops to approximately 0.5µA. When not
used, the ENABLE pin may be connected to VIN.
Internal to the part, the ENABLE pin is connected to an
input resistor-zener diode circuit, as shown in Figure 4,
creating a nonlinear input impedance. The ENABLE Pin
Current versus Applied Voltage relationship is shown in
Figure 5. When the ENABLE pin is connected to a voltage
greater than 10V, a series resistor may be used to limit the
current.
ERROR FLAG
The error indication pin, only available on the SO-8 package
version, provides a fault indication out-of-regulation condition. During a fault condition, ERROR is pulled LOW by an
open drain output device. The pin voltage, in the fault state,
is typically less than 0.2V at 500µA.
A fault condition is indicated when the output voltage differs
(either above or below) from the specified value by approximately 10%. Figure 6 shows a typical fault-monitoring
application.
+5V
10kΩ
Pull-up
µP
6 ERROR 3
ENABLE
Open
Drain
SO-8 Package
Only
REG103
FIGURE 6. ERROR Pin Typical Fault-Monitoring Circuit.
ENABLE
175kΩ
VZ = 10V
FIGURE 4. ENABLE Pin Equivalent Input Circuit.
OUTPUT NOISE
A precision band-gap reference is used for the internal
reference voltage, VREF, for the REG103. This reference is
the dominant noise source within the REG103. It generates
approximately 45µVrms in the 10Hz to 100kHz bandwidth
at the reference output. The regulator control loop gains up
the reference noise, so that the noise voltage of the regulator
is approximately given by:
VN = 45µVrms
REG103
SBVS010D
V
R1 + R 2
= 45µVrms • OUT
R2
VREF
9
Since the value of VREF is 1.295V, this relationship reduces to:
10.0
µVrms
• VOUT
V
Connecting a capacitor, CNR, from the Noise-Reduction
(NR) pin to ground, can reduce the output noise voltage.
Adding CNR, as shown in Figure 7, forms a low-pass filter
for the voltage reference. For CNR = 10nF, the total noise in
the 10Hz to 100kHz bandwidth is reduced by approximately
a factor of 3.5, as shown in Figure 8.
nV/√Hz
VN = 35
1.0
COUT = 0, CFB = 0
COUT = 0, CFB = 0.01µF
COUT = 10µF, CFB = 0.01µF
0.1
10
100
1000
Output Noise Voltage
(µVRMS 10Hz - 100kHz)
45
10000
100000
Frequency
FIGURE 9. Output Noise Density on Adjustable Versions.
The REG103 utilizes an internal charge pump to develop an
internal supply voltage sufficient to drive the gate of the
DMOS pass element above VIN. The charge-pump switching noise (nominal switching frequency = 2MHz) is not
measurable at the output of the regulator.
35
25
0.001
COUT = 0
COUT = 10µF
0.01
0.1
1
CNR (µF)
FIGURE 8. Output Noise versus Noise-Reduction Capacitor.
The REG103 adjustable version does not have the noisereduction pin available, however, the adjust pin is the summing junction of the error amplifier. A capacitor, CFB,
connected from the output to the adjust pin will reduce both
the output noise and the peak error from a load transient.
Figure 9 shows improved output noise performance for two
capacitor combinations.
DROP-OUT VOLTAGE
The REG103 uses an N-channel DMOS as the “pass”
element. When the input voltage is within a few hundred
millivolts of the output voltage, the DMOS device behaves
like a resistor. Therefore, for low values of VIN to VOUT, the
regulator’s input-to-output resistance is the RdsON of the
DMOS pass element (typically 230mΩ). For static (DC)
loads, the REG103 will typically maintain regulation down
to VIN to VOUT voltage drop of 115mV at full-rated output
current. In Figure 10, the bottom line (DC dropout) shows
the minimum VIN to VOUT voltage drop required to prevent
drop-out under DC load conditions.
VIN
NR
(fixed output
versions only)
Low Noise
Charge Pump
CNR
(optional)
VREF
(1.295V)
DMOS
Output
VOUT
Over Current
Over Temp
Protection
ENABLE
R1
R2
Adj
(Adjustable
Versions)
REG103
NOTE: R1 and R2 are internal
on fixed output versions.
ERROR
FIGURE 7. Block Diagram.
10
REG103
SBVS010D
For large step changes in load current, the REG103 requires
a larger voltage drop across it to avoid degraded transient
response. The boundary of this “transient drop-out” region is
shown as the top line in Figure 10. Values of VIN to VOUT
voltage drop above this line insure normal transient response.
REG103–3.3 at 25°C
250
200
150
100
50
0
0
100
200
300
400
500
IOUT (mA)
FIGURE 10. Transient and DC Dropout.
In the transient dropout region between “DC” and “Transient”, transient response recovery time increases. The time
required to recover from a load transient is a function of both
the magnitude and rate of the step change in load current and
the available “headroom” VIN to VOUT voltage drop. Under
worst-case conditions (full-scale load change with VIN to
VOUT voltage drop close to DC dropout levels), the REG103
can take several hundred microseconds to re-enter the specified window of regulation.
TRANSIENT RESPONSE
The REG103 response to transient line and load conditions
improves at lower output voltages. The addition of a capacitor (nominal value 10nF) from the output pin to ground may
improve the transient response. In the adjustable version, the
addition of a capacitor, CFB (nominal value 10nF), from the
output to the adjust pin will also improve the transient
response.
POWER DISSIPATION
The REG103 is available in three different package configurations. The ability to remove heat from the die is different
for each package type and, therefore, presents different
considerations in the printed circuit board (PCB) layout. The
PCB area around the device that is free of other components
moves the heat from the device to the ambient air. While it
is difficult to impossible to quantify all of the variables in a
thermal design of this type, performance data for several
configurations are shown in Figure 11. In all cases, the PCB
copper area is bare copper, free of solder-resist mask, and
not solder plated. All examples are for 1-ounce copper.
Using heavier copper will increase the effectiveness in
moving the heat from the device. In those examples where
there is copper on both sides of the PCB, no connection has
been provided between the two sides. The addition of plated
through holes will improve the heat sink effectiveness.
6
CONDITIONS
#1
#2
#3
#4
#5
5
Power Dissipation (W)
Drop-Out Voltage (mV)
DC
Transient
limited to 125°C, maximum. To estimate the margin of
safety in a complete design (including heat sink), increase
the ambient temperature until the thermal protection is
triggered. Use worst-case loads and signal conditions. For
good reliability, thermal protection should trigger more than
35°C above the maximum expected ambient condition of
your application. This produces a worst-case junction temperature of 125°C at the highest expected ambient temperature and worst-case load.
The internal protection circuitry of the REG103 has been
designed to protect against overload conditions. It was not
intended to replace proper heat sinking. Continuously running the REG103 into thermal shutdown will degrade reliability.
4
3
2
1
THERMAL PROTECTION
Power dissipated within the REG103 will cause the junction
temperature to rise. The REG103 has thermal shutdown
circuitry that protects the regulator from damage. The thermal protection circuitry disables the output when the junction temperature reaches approximately 150°C, allowing the
device to cool. When the junction temperature cools to
approximately 130°C, the output circuitry is again enabled.
Depending on various conditions, the thermal protection
circuit may cycle on and off. This limits the dissipation of
the regulator, but may have an undesirable effect on the load.
Any tendency to activate the thermal protection circuit
indicates excessive power dissipation or an inadequate heat
sink. For reliable operation, junction temperature should be
REG103
SBVS010D
0
0
25
50
75
100
125
150
Ambient Temperature (°C)
CONDITION
PACKAGE
PCB AREA
θ JA
1
DDPAK
4in2 Top Side Only
27°C/W
2
SOT-223
4in2 Top Side Only
53°C/W
3
DDPAK
None
65°C/W
4
5
SOT-223
SO-8
0.5in2 Top Side Only
None
110°C/W
150°C/W
FIGURE 11. Maximum Power Dissipation versus Ambient
Temperature for the Various Packages and
PCB Heat Sink Configurations.
11
Power dissipation depends on input voltage and load conditions. Power dissipation is equal to the product of the
average output current times the voltage across the output
element, VIN to VOUT voltage drop.
PD = (VIN – VOUT ) • I OUT ( AVG )
Power dissipation can be minimized by using the lowest
possible input voltage necessary to assure the required
output voltage.
REGULATOR MOUNTING
The tab of both packages is electrically connected to ground.
For best thermal performance, the tab of the DDPAK surface-mount version should be soldered directly to a circuit-
board copper area. Increasing the copper area improves heat
dissipation. Figure 12 shows typical thermal resistance from
junction to ambient as a function of the copper area for the
DDPAK.
Although the tabs of the DDPAK and the SOT-223 are
electrically grounded, they are not intended to carry any
current. The copper pad that acts as a heat sink should be
isolated from the rest of the circuit to prevent current flow
through the device from the tab to the ground pin. Solder pad
footprint recommendations for the various REG103 devices
are presented in the Application Bulletin “Solder Pad Recommendations for Surface-Mount Devices” (SBFA015),
available from the Texas Instruments web site (www.ti.com).
THERMAL RESISTANCE vs PCB COPPER AREA
Thermal Resistance, θJA (°C/W)
50
Circuit-Board Copper Area
REG103
Surface-Mount Package
1 oz. copper
40
30
20
10
REG103
DDPAK Surface-Mount Package
0
0
1
2
3
4
5
Copper Area (Inches2)
FIGURE 12. Thermal Resistance versus PCB Area for the Five-Lead DDPAK.
THERMAL RESISTANCE vs PCB COPPER AREA
Thermal Resistance, θJA (°C/W)
180
Circuit-Board Copper Area
REG103
Surface-Mount Package
1 oz. copper
160
140
120
100
80
60
40
20
REG103
SOT-223 Surface-Mount Package
0
0
1
2
3
4
5
Copper Area (Inches2)
FIGURE 13. Thermal Resistance versus PCB Area for the Five-Lead SOT-223.
12
REG103
SBVS010D
PACKAGE OPTION ADDENDUM
www.ti.com
14-Oct-2022
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
Samples
(4/5)
(6)
REG103FA-2.5KTTT
ACTIVE
DDPAK/
TO-263
KTT
5
50
RoHS & Green
Call TI | SN
Level-2-260C-1 YEAR
-40 to 85
REG
103FA-2.5
Samples
REG103FA-2.5KTTTG3
ACTIVE
DDPAK/
TO-263
KTT
5
50
RoHS & Green
SN
Level-2-260C-1 YEAR
-40 to 85
REG
103FA-2.5
Samples
REG103FA-3.3KTTT
ACTIVE
DDPAK/
TO-263
KTT
5
50
RoHS & Green
Call TI | SN
Level-2-260C-1 YEAR
-40 to 85
REG
103FA-3.3
Samples
REG103FA-5KTTT
ACTIVE
DDPAK/
TO-263
KTT
5
50
RoHS & Green
Call TI | SN
Level-2-260C-1 YEAR
-40 to 85
REG
103FA-5
Samples
REG103FA-5KTTTG3
ACTIVE
DDPAK/
TO-263
KTT
5
50
RoHS & Green
SN
Level-2-260C-1 YEAR
-40 to 85
REG
103FA-5
Samples
REG103FA-A/500
ACTIVE
DDPAK/
TO-263
KTT
5
500
RoHS & Green
Call TI | SN
Level-2-260C-1 YEAR
-40 to 85
REG
103FA-A
Samples
REG103FA-AKTTT
ACTIVE
DDPAK/
TO-263
KTT
5
50
RoHS & Green
Call TI | SN
Level-2-260C-1 YEAR
-40 to 85
REG
103FA-A
Samples
REG103GA-2.5
ACTIVE
SOT-223
DCQ
6
78
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 85
R103G25
Samples
REG103GA-3.3
ACTIVE
SOT-223
DCQ
6
78
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 85
R103G33
Samples
REG103GA-3.3/2K5
ACTIVE
SOT-223
DCQ
6
2500
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 85
R103G33
Samples
REG103GA-5
ACTIVE
SOT-223
DCQ
6
78
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 85
R103G50
Samples
REG103GA-5/2K5
ACTIVE
SOT-223
DCQ
6
2500
RoHS & Green
SN
Level-2-260C-1 YEAR
-40 to 85
R103G50
Samples
REG103GA-5G4
ACTIVE
SOT-223
DCQ
6
78
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 85
R103G50
Samples
REG103GA-A
ACTIVE
SOT-223
DCQ
6
78
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 85
R103GA
Samples
REG103GA-A/2K5
ACTIVE
SOT-223
DCQ
6
2500
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 85
R103GA
Samples
REG103GA-AG4
ACTIVE
SOT-223
DCQ
6
78
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 85
R103GA
Samples
REG103UA-2.5
ACTIVE
SOIC
D
8
75
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 85
REG
103U25
Samples
REG103UA-2.5/2K5
ACTIVE
SOIC
D
8
2500
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 85
REG
103U25
Samples
Addendum-Page 1
PACKAGE OPTION ADDENDUM
www.ti.com
14-Oct-2022
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
Samples
(4/5)
(6)
REG103UA-3.3
ACTIVE
SOIC
D
8
75
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 85
REG
103UA4
Samples
REG103UA-3.3/2K5
ACTIVE
SOIC
D
8
2500
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 85
REG
103UA4
Samples
REG103UA-5
ACTIVE
SOIC
D
8
75
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 85
REG
103U50
Samples
REG103UA-5/2K5
ACTIVE
SOIC
D
8
2500
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 85
REG
103U50
Samples
REG103UA-A
ACTIVE
SOIC
D
8
75
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 85
REG
103U-A
Samples
REG103UA-A/2K5
ACTIVE
SOIC
D
8
2500
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 85
REG
103U-A
Samples
REG103UA-AG4
ACTIVE
SOIC
D
8
75
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 85
REG
103U-A
Samples
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of
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