TI TPS79501DRBR

TPS795xx
www.ti.com
SLVS350G – OCTOBER 2002 – REVISED JULY 2006
ULTRALOW-NOISE, HIGH-PSRR, FAST, RF, 500-mA
LOW-DROPOUT LINEAR REGULATORS
FEATURES
•
•
•
•
•
•
•
500-mA Low-Dropout Regulator With Enable
Available in Fixed and Adjustable (1.2-V to
5.5-V) Versions
High PSRR (50 dB at 10 kHz)
Ultralow Noise (33 µVRMS, TPS79530)
Fast Start-Up Time (50 µs)
Stable With a 1-µF Ceramic Capacitor
Excellent Load/Line Transient Response
Very Low Dropout Voltage (110 mV at Full
Load, TPS79530)
6-Pin SOT223 and 3 × 3 SON Packages
The TPS795xx family of low-dropout (LDO),
low-power linear voltage regulators features high
power-supply rejection ratio (PSRR), ultralow noise,
fast start-up, and excellent line and load transient
responses in small outline, SOT223-6 and 3 x 3 SON
packages. Each device in the family is stable with a
small 1-µF ceramic capacitor on the output. The
family uses an advanced, proprietary BiCMOS
fabrication process to yield extremely low dropout
voltages (for example, 110 mV at 500 mA). Each
device achieves fast start-up times (approximately 50
µs with a 0.001-µF bypass capacitor) while
consuming very low quiescent current (265 µA,
typical). Moreover, when the device is placed in
standby mode, the supply current is reduced to less
than 1 µA. The TPS79530 exhibits approximately 33
µVRMS of output voltage noise at 3.0 V output with a
0.1-µF bypass capacitor. Applications with analog
components that are noise-sensitive, such as
portable RF electronics, benefit from the high-PSRR
and low-noise features, as well as from the fast
response time.
APPLICATIONS
•
•
•
•
•
RF: VCOs, Receivers, ADCs
Audio
Bluetooth®, Wireless LAN
Cellular and Cordless Telephones
Handheld Organizers, PDAs
DRB PACKAGE
3mm x 3mm SON
(TOP VIEW)
IN 2
DCQ PACKAGE OUT 3
OUT 4
SOT223-6
(TOP VIEW)
EN
IN
GND
OUT
NR/FB
1
2
3
4
5
8 EN
7 NC
6 GND
5 NR/FB
6
GND
TPS79530
OUTPUT SPECTRAL NOISE DENSITY
vs
FREQUENCY
80
0.5
VIN = 4 V
COUT = 10 mF
CNR = 0.01 mF
70
Ripple Rejection − dB
IN 1
TPS79530
RIPPLE REJECTION
vs
FREQUENCY
Output Spectral Noise Density − mV/ÖHz
•
•
DESCRIPTION
IOUT = 1 mA
60
50
40
IOUT = 500 mA
30
20
10
0
1
10
100
1 k 10 k 100 k 1 M
Frequency (Hz)
10 M
VIN = 5.5 V
COUT = 2.2 mF
CNR = 0.1 mF
0.4
0.3
IOUT = 1 mA
0.2
IOUT = 0.5 A
0.1
0
100
1k
10 k
Frequency (Hz)
100 k
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.
Bluetooth is a registered trademark of Bluetooth SIG, Inc.
All other trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2002–2006, Texas Instruments Incorporated
TPS795xx
www.ti.com
SLVS350G – OCTOBER 2002 – REVISED JULY 2006
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.
ORDERING INFORMATION (1)
VOUT (2)
PRODUCT
TPS795xxyyyz
(1)
(2)
XX is nominal output voltage (for example, 28 = 2.8 V, 285 = 2.85 V, 01 = Adjustable).
YYY is package designator.
Z is package quantity.
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.
Output voltages from 1.3 V to 5.0 V in 100 mV increments are available; minimum order quantities may apply. Contact factory for details
and availability.
ABSOLUTE MAXIMUM RATINGS
over operating temperature (unless otherwise noted) (1)
VALUE
VIN range
– 0.3 V to 6 V
VEN range
–0.3 V to VIN + 0.3 V
VOUT range
6V
Peak output current
Internally limited
ESD rating, HBM
2 kV
ESD rating, CDM
500 V
Continuous total power dissipation
See Dissipation Rating Table
Junction temperature range, TJ
–40°C to +150°C
Storage temperature range, Tstg
–65°C to +150°C
(1)
Stresses above these ratings may cause permanent damage. Exposure to absolute maximum conditions for extended periods may
degrade device reliability. These are stress ratings only, and functional operation of the device at these or any other conditions beyond
those specified is not implied.
DISSIPATION RATING TABLE
(1)
(2)
2
PACKAGE
BOARD
RθJC
RθJA
SOT223
Low K (1)
15°C/W
53°C/W
3 x 3 SON
High-K (2)
1.2°C/W
40°C/W
The JEDEC low-K (1s) board design used to derive this data was a 3-inch × 3-inch (7.5 cm × 7.5cm), two-layer board with 2-ounce
copper traces on top of the board.
The JEDEC high-K (2s2p) board design used to derive this data was a 3-inch × 3-inch (7,5-cm × 7,5-cm), multilayer board with 1-ounce
internal power and ground planes and 2-ounce copper traces on top and bottom of the board.
Submit Documentation Feedback
TPS795xx
www.ti.com
SLVS350G – OCTOBER 2002 – REVISED JULY 2006
ELECTRICAL CHARACTERISTICS
Over recommended operating temperature range (TJ = –40°C to +125°C), VEN = VIN, VIN = VOUT(nom) + 1 V (1), IOUT = 1 mA,
COUT = 10 µF, CNR = 0.01 µF, unless otherwise noted. Typical values are at +25°C.
PARAMETER
TEST CONDITIONS
Input voltage, VIN (1)
1.200
Continuous output current, IOUT
Output voltage range
Accuracy
TPS79501
1.225
0.98(VOUT)
0 µA ≤ IOUT ≤ 500 mA, VOUT + 1 V ≤ VIN ≤ 5.5 V (1)
–2.0
Fixed VOUT
VOUT + 1 V ≤ VIN ≤ 5.5 V
Load regulation (∆VOUT%/∆IOUT)
0 µA ≤ IOUT ≤ 500 mA,
1.250
500
1.225
TPS79501 (2) 0 µA ≤ IOUT ≤ 500 mA, VOUT + 1 V ≤ VIN ≤ 5.5 V (1)
MAX
5.5
0
Output voltage line regulation (∆VOUT%/∆VIN) (1)
Dropout voltage (3)
VIN = VOUT(nom) - 0.1 V
TYP
2.7
Internal reference, VFB (TPS79501)
Output
voltage
MIN
5.5 – VDO
VOUT
0.05
V
V
mA
V
1.02(VOUT)
V
+2.0
%
0.12
%/V
3
mV
TPS79530
IOUT = 500 mA
110
170
TPS79533
IOUT = 500 mA
105
160
mV
Output current limit
VOUT = 0 V
2.8
4.2
A
Ground pin current
0 µA ≤ IOUT ≤ 500 mA
265
385
µA
Shutdown current (4)
VEN = 0 V, 2.7 V ≤ VIN ≤ 5.5 V
0.07
1
µA
FB pin current
VFB = 1.225 V
1
µA
Power-supply ripple rejection
TPS79530
2.4
UNIT
f = 100 Hz, IOUT = 10 mA
59
f = 100 Hz, IOUT = 500 mA
58
f = 10 kHz, IOUT = 500 mA
50
f = 100 kHz, IOUT = 500 mA
Output noise voltage (TPS79530)
Time, start-up (TPS79530)
BW = 100 Hz to 100 kHz,
IOUT = 500 mA
RL = 6 Ω, COUT = 1 µF
39
CNR = 0.001 µF
46
CNR = 0.0047 µF
41
CNR = 0.01 µF
35
CNR = 0.1 µF
33
CNR = 0.001 µF
50
CNR = 0.0047 µF
µs
110
High-level enable input voltage
2.7 V ≤ VIN ≤ 5.5 V
Low-level enable input voltage
2.7 V ≤ VIN ≤ 5.5 V
EN pin current
VEN = 0 V
1
UVLO threshold
VCC rising
2.25
UVLO hysteresis
µVRMS
75
CNR = 0.01 µF
(1)
(2)
(3)
(4)
dB
1.7
VIN
V
1
µA
2.65
100
V
0.7
V
mV
Minimum VIN is 2.7 V or VOUT + VDO, whichever is greater.
Tolerance of external resistors not included in this specification.
Dropout is not measured for the TPS79501 and TPS79525 since minimum VIN = 2.7 V.
For adjustable version, this applies only after VIN is applied; then VEN transitions high to low.
Submit Documentation Feedback
3
TPS795xx
www.ti.com
SLVS350G – OCTOBER 2002 – REVISED JULY 2006
FUNCTIONAL BLOCK DIAGRAM—ADJUSTABLE VERSION
IN
OUT
300Ω
Current
Sense
UVLO
Overshoot
Detect
GND
ILIM
SHUTDOWN
R1
EN
FB
UVLO
Thermal
Shutdown
R2
Quickstart
Bandgap
Reference
1.225 V
VIN
External to
the Device
VREF
250 kΩ
FUNCTIONAL BLOCK DIAGRAM—FIXED VERSION
IN
OUT
300Ω
Current
Sense
UVLO
Overshoot
Detect
GND
ILIM
SHUTDOWN
R1
EN
UVLO
Thermal
Shutdown
R2
R2 = 40 kΩ
Quickstart
VIN
Bandgap
Reference
1.225 V
VREF
NR
250 kΩ
Table 1. Terminal Functions
SOT223 (DCQ)
PIN NO.
3x3 SON (DRB)
PIN NO.
2
1, 2
3, 6
6
Regulator ground
EN
1
8
Driving the enable pin (EN) high turns on the regulator. Driving this pin low puts the regulator into
shutdown mode. EN can be connected to IN if not used.
NR
5
5
Noise-reduction pin for fixed versions only. Connecting an external capacitor to this pin bypasses
noise generated by the internal bandgap, which improves power-supply rejection and reduces
output noise. (Not available on adjustable versions.)
FB
5
5
Feedback input voltage for the adjustable device. (Not available on fixed voltage versions.)
OUT
4
3, 4
NC
–
7
NAME
IN
GND
4
DESCRIPTION
Unregulated input to the device
Regulator output.
Not connected
Submit Documentation Feedback
TPS795xx
www.ti.com
SLVS350G – OCTOBER 2002 – REVISED JULY 2006
TYPICAL CHARACTERISTICS
TPS79530
OUTPUT VOLTAGE
vs OUTPUT CURRENT
TPS79530
OUTPUT VOLTAGE
vs JUNCTION TEMPERATURE
TPS79530
GROUND CURRENT
vs JUNCTION TEMPERATURE
3.005
3.02
276
VIN = 4 V
COUT = 10 µF
3
3.01
272
IOUT = 1 mA
2.995
VIN = 4 V
COUT = 10 µF
274
IOUT = 1 mA
3
IGND (µA)
VOUT (V)
VOUT (V)
270
2.99
IOUT = 0.5 A
2.985
2.98
2.99
0
0.1
0.2
0.3
IOUT (mA)
0.4
2.97
0.5
260
−40 −25 −10 5
20 35 50 65 80 95 110 125
TJ (°C)
Figure 3.
TPS79530
OUTPUT SPECTRAL
NOISE DENSITY
vs FREQUENCY
TPS79530
OUTPUT SPECTRAL
NOISE DENSITY
vs FREQUENCY
TPS79530
OUTPUT SPECTRAL
NOISE DENSITY
vs FREQUENCY
2.5
0.4
IOUT = 1 mA
0.2
IOUT = 0.5 A
1k
10 k
Frequency (Hz)
VIN = 5.5 V
COUT = 10 µF
CNR = 0.1 µF
0.5
0.4
IOUT = 1 mA
0.3
0.2
IOUT = 0.5 A
0.1
0
100
100 k
Output Spectral Noise Density − µV//Hz
0.6
0.1
20 35 50 65 80 95 110 125
Figure 2.
Output Spectral Noise Density − µV//Hz
1k
10 k
2
CNR = 0.001 µF
VIN = 5.5 V
IOUT = 500 mA
COUT= 10 µF
CNR = 0.0047 µF
1.5
CNR = 0.01 µF
1
CNR = 0.1 µF
0.5
0
100
100 k
1k
10 k
Frequency (Hz)
Frequency (Hz)
Figure 4.
Figure 5.
Figure 6.
TPS79530
ROOT MEAN SQUARED
OUTPUT NOISE vs CNR
TPS79530
DROPOUT VOLTAGE
vs JUNCTION TEMPERATURE
TPS79530
RIPPLE REJECTION
vs FREQUENCY
50
150
40
VIN = 2.9 V
COUT = 10 µF
IOUT = 500 mA
VDO (mV)
20
VIN = 4 V
COUT = 10 µF
CNR = 0.1 µF
70
125
30
100 k
80
175
IOUT = 500 mA
COUT= 10 µF
Ripple Rejection − dB
Output Spectral Noise Density − µV//Hz
−40 −25 −10 5
Figure 1.
VIN = 5.5 V
COUT = 2.2 µF
CNR = 0.1 µF
0
100
RMS − Root Mean Squared Output Noise − µVRMS
262
TJ (°C)
0.5
0.3
IOUT = 0.5 A
266
264
2.975
2.98
268
100
75
50
IOUT = 1 mA
60
50
40
IOUT = 500 mA
30
20
10
25
10
BW = 100 Hz to 100 kHz
0
0.001
0.01
0.0047
CNR (µF)
Figure 7.
0.1
0
−40 −25 −10 5
20 35 50 65 80 95 110 125
TJ (°C)
Figure 8.
Submit Documentation Feedback
0
1
10
100
1 k 10 k 100 k 1 M
Frequency (Hz)
10 M
Figure 9.
5
TPS795xx
www.ti.com
SLVS350G – OCTOBER 2002 – REVISED JULY 2006
TYPICAL CHARACTERISTICS (continued)
TPS79530
RIPPLE REJECTION
vs FREQUENCY
TPS79530
RIPPLE REJECTION
vs FREQUENCY
Ripple Rejection − dB
IOUT = 1 mA
60
50
40
IOUT = 500 mA
30
VIN = 4 V
COUT = 2.2 µF
CNR = 0.01 µF
70
IOUT = 1 mA
50
40
30
IOUT = 500 mA
IOUT = 500 mA
10
10
0
0
100
1 k 10 k 100 k 1 M
Frequency (Hz)
1
10 M
10
100
1 k 10 k 100 k 1 M
Frequency (Hz)
0
10 M
1
1 k 10 k 100 k 1 M 10 M
Frequency (Hz)
Figure 12.
TPS79530
START-UP TIME
TPS79518
LINE TRANSIENT RESPONSE
TPS79530
LINE TRANSIENT RESPONSE
CNR = 0.01 µF
Enable
1.75
20
30
10
20
VOUT (mV)
CNR = 0.0047 µF
2
0
−10
10
0
−10
1.50
−20
1.25
1
COUT = 10 µF, CNR = 0.01 µF,
IOUT = 0.5 A, dv/dt = 1 V/µs
0.25
0
0
100
200
300
400
−20
VIN (V)
VIN = 4 V
COUT = 10 µF
IOUT = 0.5 A
0.50
VIN (V)
4
0.75
3
COUT = 10 µF, CNR = 0.01 µF,
IOUT = 0.5 A, dv/dt = 1 V/µs
5
4
3
2
500 600
0
50
100
150
200
0
50
t (µs)
t (µs)
100
t (µs)
150
Figure 13.
Figure 14.
Figure 15.
TPS79530
LOAD TRANSIENT RESPONSE
TPS79525
POWER UP/POWER DOWN
TPS79530
DROPOUT VOLTAGE
vs OUTPUT CURRENT
60
4.5
40
4
20
3.5
160
−20
−40
COUT = 10 µF, CNR = 0.01 µF,
VL = 3.8 V, dv/dt = 0.5 A/µs
140
VIN
TJ = 25°C
2
1.5
100
80
60
VOUT
1
0.5
40
0
0
20
−0.5
−0.5
0.5
200
400
600
t (µs)
Figure 16.
800
1000
TJ = 125°C
120
2.5
VDO (mV)
VOUT (V)
0
200
180
VOUT = 2.5 V,
RL = 10 Ω
3
0
100
Figure 11.
2.25
−60
10
Figure 10.
CNR = 0.001 µF
2.50
DVOUT (mV)
30
10
3
IOUT (A)
40
20
2.75
6
50
20
10
IOUT = 1 mA
60
20
1
VIN = 4 V
COUT = 2.2 µF
CNR = 0.1 µF
70
60
VOUT (mV)
Ripple Rejection − dB
70
VIN (V)
80
80
VIN = 4 V
COUT = 10 µF
CNR = 0.01 µF
Ripple Rejection − dB
80
TPS79530
RIPPLE REJECTION
vs FREQUENCY
0
400
800
1200
1600
2000
TJ = −40°C
0
Time (µs)
200
300
IOUT (mA)
Figure 17.
Figure 18.
Submit Documentation Feedback
0
100
400
500
TPS795xx
www.ti.com
SLVS350G – OCTOBER 2002 – REVISED JULY 2006
TYPICAL CHARACTERISTICS (continued)
TPS79530
TYPICAL REGIONS OF STABILITY
EQUIVALENT SERIES RESISTANCE
(ESR)
vs OUTPUT CURRENT
TPS79501
DROPOUT VOLTAGE
vs INPUT VOLTAGE
100
200
100
COUT = 1 µF
COUT = 10 µF,
CNR = 0.01 µF,
IOUT = 50 mA
150
COUT = 2.2 µF
Region of
Instability
10
50
1
Region of Stability
0.1
TJ = −40°C
2.5
3
3.5
4
VIN (V)
4.5
0
5
100
200
300
IOUT (mA)
Figure 19.
1
Region of Stability
0.1
0.01
0
400
Region of
Instability
10
ESR (W)
ESR (W)
TJ = 25°C
500
0.01
1
10
100
1000
IOUT (mA)
Figure 20.
Figure 21.
TPS79530
TYPICAL REGIONS OF STABILITY
EQUIVALENT SERIES RESISTANCE
(ESR)
vs OUTPUT CURRENT
100
COUT = 10 µF
10
ESR (W)
VDO (mV)
TJ = 125°C
100
TPS79530
TYPICAL REGIONS OF STABILITY
EQUIVALENT SERIES RESISTANCE
(ESR)
vs OUTPUT CURRENT
Region of
Instability
1
Region of Stability
0.1
0.01
0
100
200
300
400
500
IOUT (A)
Figure 22.
Submit Documentation Feedback
7
TPS795xx
www.ti.com
SLVS350G – OCTOBER 2002 – REVISED JULY 2006
APPLICATION INFORMATION
The TPS795xx family of low-dropout (LDO)
regulators has been optimized for use in
noise-sensitive equipment. The device features
extremely low dropout voltages, high PSRR, ultralow
output noise, low quiescent current (265 µA
typically), and an enable input to reduce supply
currents to less than 1 µA when the regulator is
turned off.
A typical application circuit is shown in Figure 23.
VIN
IN
VOUT
OUT
TPS795xx
1m F
EN
GND
1m F
NR
0.01mF
Figure 23. Typical Application Circuit
EXTERNAL CAPACITOR REQUIREMENTS
Although not required, it is good analog design
practice to place a 0.1µF — 2.2µF capacitor near the
input of the regulator to counteract reactive input
sources. A higher-value input capacitor may be
necessary if large, fast-rise-time load transients are
anticipated and the device is located several inches
from the power source.
Like most low-dropout regulators, the TPS795xx
requires an output capacitor connected between
OUT and GND to stabilize the internal control loop.
The minimum recommended capacitor is 1 µF. Any 1
µF or larger ceramic capacitor is suitable.
The internal voltage reference is a key source of
noise in an LDO regulator. The TPS795xx has an
NR pin which is connected to the voltage reference
through a 250-kΩ internal resistor. The 250-kΩ
internal resistor, in conjunction with an external
bypass capacitor connected to the NR pin, creates a
low-pass filter to reduce the voltage reference noise
and, therefore, the noise at the regulator output. In
order for the regulator to operate properly, the
current flow out of the NR pin must be at a minimum,
8
because any leakage current creates an IR drop
across the internal resistor, thus creating an output
error. Therefore, the bypass capacitor must have
minimal leakage current. The bypass capacitor
should be no more than 0.1-µF in order to ensure
that it is fully charged during the quickstart time
provided by the internal switch shown in the
Functional Block Diagram.
For example, the TPS79530 exhibits only 33 µVRMS
of output voltage noise using a 0.1-µF ceramic
bypass capacitor and a 10-µF ceramic output
capacitor. Note that the output starts up slower as
the bypass capacitance increases because of the RC
time constant at the bypass pin that is created by the
internal 250-kΩ resistor and external capacitor.
BOARD LAYOUT RECOMMENDATION TO
IMPROVE PSRR AND NOISE
PERFORMANCE
To improve ac measurements such as PSRR, output
noise, and transient response, it is recommended
that the board be designed with separate ground
planes for VIN and VOUT, with each ground plane
connected only at the ground pin of the device. In
addition, the ground connection for the bypass
capacitor should connect directly to the ground pin of
the device.
REGULATOR MOUNTING
The tab of the SOT223-6 package is electrically
connected to ground. For best thermal performance,
the tab of the surface-mount version should be
soldered directly to a circuit-board copper area.
Increasing the copper area improves heat
dissipation.
Solder pad footprint recommendations for the
devices are presented in Application Report
SBFA015, Solder Pad Recommendations for
Surface-Mount Devices, available from the TI web
site (www.ti.com).
Submit Documentation Feedback
TPS795xx
www.ti.com
SLVS350G – OCTOBER 2002 – REVISED JULY 2006
PROGRAMMING THE TPS79501
ADJUSTABLE LDO REGULATOR
The approximate value of this capacitor can be
calculated as Equation 3:
(3 10 *7) (R 1 ) R 2)
C1 +
(R 1 R 2)
(3)
The output voltage of the TPS79501 adjustable
regulator is programmed using an external resistor
divider as shown in Figure 24. The output voltage is
calculated using Equation 1:
V OUT + VREF
ǒ1 ) RR Ǔ
The suggested value of this capacitor for several
resistor ratios is shown in the table within Figure 24.
If this capacitor is not used (such as in a unity-gain
configuration), then the minimum recommended
output capacitor is 2.2 µF instead of 1 µF.
1
2
(1)
where:
• VREF = 1.2246 V typ (the internal reference
voltage)
REGULATOR PROTECTION
The TPS795xx PMOS-pass transistor has a built-in
back diode that conducts reverse current when the
input voltage drops below the output voltage (for
example, during power down). Current is conducted
from the output to the input and is not internally
limited. If extended reverse voltage operation is
anticipated, external limiting might be appropriate.
Resistors R1 and R2 should be chosen for
approximately 40-µA divider current. Lower value
resistors can be used for improved noise
performance, but the device wastes more power.
Higher values should be avoided, as leakage current
at FB increases the output voltage error.
The TPS795xx features internal current limiting and
thermal protection. During normal operation, the
TPS795xx limits output current to approximately 2.8
A. When current limiting engages, the output voltage
scales back linearly until the overcurrent condition
ends. While current limiting is designed to prevent
gross device failure, care should be taken not to
exceed the power dissipation ratings of the package.
If the temperature of the device exceeds
approximately 165°C, thermal-protection circuitry
shuts it down. Once the device has cooled down to
below approximately 140°C, regulator operation
resumes.
The recommended design procedure is to choose
R2 = 30.1 kΩ to set the divider current at 40 µA,
C1 = 15 pF for stability, and then calculate R1 using
Equation 2:
VOUT
R1 +
*1
R2
VREF
ǒ
Ǔ
(2)
In order to improve the stability of the adjustable
version, it is suggested that a small compensation
capacitor be placed between OUT and FB.
VIN
IN
1m F
EN
OUT
TPS79501
GND
OUTPUT VOLTAGE
PROGRAMMING GUIDE
VOUT
R1
FB
C1
1m F
OUTPUT
VOLTAGE
R1
1.8 V
3.6 V
R2
R2
C1
14.0 kW
30.1 kW
33 pF
57.9 kW
30.1 kW
15 pF
Figure 24. TPS79501 Adjustable LDO Regulator Programming
Submit Documentation Feedback
9
TPS795xx
www.ti.com
SLVS350G – OCTOBER 2002 – REVISED JULY 2006
THERMAL INFORMATION
The amount of heat that an LDO linear regulator
generates is directly proportional to the amount of
power it dissipates during operation. All integrated
circuits have a maximum allowable junction
temperature (TJmax) above which normal operation
is not assured. A system designer must design the
operating environment so that the operating junction
temperature (TJ) does not exceed the maximum
junction temperature (TJmax). The two main
environmental variables that a designer can use to
improve thermal performance are air flow and
external heatsinks. The purpose of this information is
to aid the designer in determining the proper
operating environment for a linear regulator that is
operating at a specific power level.
In general, the maximum expected power (PDmax)
consumed by a linear regulator is computed as
shown in Equation 4:
P D max + ǒVIN(avg) * VOUT(avg)Ǔ
I OUT(avg) ) V I(avg)
IQ
(4)
where:
• VIN(avg) is the average input voltage
• VOUT(avg) is the average output voltage
• IOUT(avg) is the average output current
• IQ is the quiescent current
For most TI LDO regulators, the quiescent current is
insignificant compared to the average output current;
therefore, the term VIN(avg) x IQ can be neglected. The
operating junction temperature is computed by
adding the ambient temperature (TA) and the
increase in temperature due to the regulator's power
dissipation. The temperature rise is computed by
multiplying the maximum expected power dissipation
by the sum of the thermal resistances between the
junction and the case (RΘJC), the case to heatsink
(RΘCS), and the heatsink to ambient (RΘSA). Thermal
resistances are measures of how effectively an
object dissipates heat. Typically, the larger the
device, the more surface area available for power
dissipation and the lower the object's thermal
resistance.
Figure 25 illustrates these thermal resistances for a
SOT223 package mounted in a JEDEC low-K board.
10
A
TJ
RθJC
CIRCUIT BOARD COPPER AREA
C
B
B
TC
RθCS
A
C
RθSA
SOT223 Package
TA
Figure 25. Thermal Resistances
Equation 5 summarizes the computation:
ǒRθJC ) RθCS ) RθSAǓ
T J + T A ) PD max
(5)
The RΘJC is specific to each regulator as determined
by its package, lead frame, and die size provided in
the regulator's data sheet. The RΘSA is a function of
the type and size of heatsink. For example, black
body radiator type heatsinks can have RΘCS values
ranging from 5°C/W for very large heatsinks to
50°C/W for very small heatsinks. The RΘCS is a
function of how the package is attached to the
heatsink. For example, if a thermal compound is
used to attach a heatsink to a SOT223 package,
RΘCS of 1°C/W is reasonable.
Even if no external black body radiator type heatsink
is attached to the package, the board on which the
regulator is mounted provides some heatsinking
through the pin solder connections. Some packages,
like the DDPAK and SOT223 packages, use a
copper plane underneath the package or the circuit
board ground plane for additional heatsinking to
improve their thermal performance. Computer-aided
thermal modeling can be used to compute very
accurate approximations of an integrated circuit's
thermal
performance
in
different
operating
environments (for example, different types of circuit
boards, different types and sizes of heatsinks,
different air flows, etc.). Using these models, the
three thermal resistances can be combined into one
thermal resistance between junction and ambient
(RΘJA). This RΘJA is valid only for the specific
operating environment used in the computer model.
Submit Documentation Feedback
TPS795xx
www.ti.com
SLVS350G – OCTOBER 2002 – REVISED JULY 2006
Equation 5 simplifies into Equation 6:
T J + T A ) PD max
RθJA
(6)
Rearranging Equation 6 gives Equation 7:
T * TA
R θJA + J
PD max
(7)
Using Equation 6 and the computer model generated
curves shown in Figure 26, a designer can quickly
compute
the
required
heatsink
thermal
resistance/board area for a given ambient
temperature, power dissipation, and operating
environment.
To illustrate, the TPS79525 in a SOT223 package
was chosen. For this example, the average input
voltage is 3.3 V, the output voltage is 2.5 V, the
average output current is 1 A, the ambient
temperature 55°C, no air flow is present, and the
operating environment is the same as documented
below. Neglecting the quiescent current, the
maximum average power is Equation 8:
P D max + (3.3 * 2.5)V
1A + 800mW
(8)
Substituting TJmax for TJ into Equation 4 gives
Equation 9:
R θJA max + (125 * 55)°Cń800mW + 87.5°CńW
(9)
From Figure 26, RθJA vs PCB Copper Area, the
ground plane needs to be 0.55 in2 for the part to
dissipate 800 mW. The operating environment used
to construct Figure 26 consisted of a board with 1 oz.
copper planes. The package is soldered to a 1 oz.
copper pad on the top of the board. The pad is tied
through thermal vias to the 1 oz. ground plane.
No Air Flow
160
140
120
100
80
From the data in Figure 26 and rearranging equation
6, the maximum power dissipation for a different
ground plane area and a specific ambient
temperature can be computed, as shown in
Figure 27.
60
40
20
0
0.1
1
PCB Copper Area (in2)
10
Figure 26. SOT223 Thermal Resistance vs PCB
Copper Area
SOT223 POWER DISSIPATION
The SOT223 package provides an effective means
of managing power dissipation in surface-mount
applications. The SOT223 package dimensions are
provided in the Mechanical Data section at the end
of the data sheet. The addition of a copper plane
directly underneath the SOT223 package enhances
the thermal performance of the package.
PD − Maximum Power Dissipation (W)
RθJA − Thermal Resistance (°C/W)
180
6
TA = 25°C
5
4
4 in2 PCB Area
3
0.5 in2 PCB Area
2
1
0
0
25
50
75
100
125
150
TA − Ambient Temperature (°C)
Figure 27. SOT223 Maximum Power Dissipation
vs Ambient Temperature
Submit Documentation Feedback
11
PACKAGE OPTION ADDENDUM
www.ti.com
8-Oct-2007
PACKAGING INFORMATION
Orderable Device
Status (1)
Package
Type
Package
Drawing
Pins Package Eco Plan (2)
Qty
TPS79501DCQ
ACTIVE
SOT-223
DCQ
6
78
Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-2-260C-1 YEAR
TPS79501DCQG4
ACTIVE
SOT-223
DCQ
6
78
Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-2-260C-1 YEAR
TPS79501DCQR
ACTIVE
SOT-223
DCQ
6
2500 Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-2-260C-1 YEAR
TPS79501DCQRG4
ACTIVE
SOT-223
DCQ
6
2500 Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-2-260C-1 YEAR
TPS79501DRBR
ACTIVE
SON
DRB
8
3000 Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-2-260C-1 YEAR
TPS79501DRBRG4
ACTIVE
SON
DRB
8
3000 Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-2-260C-1 YEAR
TPS79501DRBT
ACTIVE
SON
DRB
8
250
Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-2-260C-1 YEAR
TPS79501DRBTG4
ACTIVE
SON
DRB
8
250
Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-2-260C-1 YEAR
TPS79516DCQ
ACTIVE
SOT-223
DCQ
6
78
Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-2-260C-1 YEAR
TPS79516DCQG4
ACTIVE
SOT-223
DCQ
6
78
Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-2-260C-1 YEAR
TPS79516DCQR
ACTIVE
SOT-223
DCQ
6
2500 Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-2-260C-1 YEAR
TPS79516DCQRG4
ACTIVE
SOT-223
DCQ
6
2500 Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-2-260C-1 YEAR
TPS79518DCQ
ACTIVE
SOT-223
DCQ
6
78
Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-2-260C-1 YEAR
TPS79518DCQG4
ACTIVE
SOT-223
DCQ
6
78
Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-2-260C-1 YEAR
TPS79518DCQR
ACTIVE
SOT-223
DCQ
6
2500 Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-2-260C-1 YEAR
TPS79518DCQRG4
ACTIVE
SOT-223
DCQ
6
2500 Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-2-260C-1 YEAR
TPS79525DCQ
ACTIVE
SOT-223
DCQ
6
78
Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-2-260C-1 YEAR
TPS79525DCQG4
ACTIVE
SOT-223
DCQ
6
78
Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-2-260C-1 YEAR
TPS79525DCQR
ACTIVE
SOT-223
DCQ
6
2500 Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-2-260C-1 YEAR
TPS79525DCQRG4
ACTIVE
SOT-223
DCQ
6
2500 Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-2-260C-1 YEAR
TPS79530DCQ
ACTIVE
SOT-223
DCQ
6
78
Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-2-260C-1 YEAR
TPS79530DCQG4
ACTIVE
SOT-223
DCQ
6
78
Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-2-260C-1 YEAR
TPS79530DCQR
ACTIVE
SOT-223
DCQ
6
2500 Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-2-260C-1 YEAR
TPS79530DCQRG4
ACTIVE
SOT-223
DCQ
6
2500 Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-2-260C-1 YEAR
TPS79533DCQ
ACTIVE
SOT-223
DCQ
6
CU NIPDAU
Level-2-260C-1 YEAR
78
Addendum-Page 1
Green (RoHS &
no Sb/Br)
Lead/Ball Finish
MSL Peak Temp (3)
PACKAGE OPTION ADDENDUM
www.ti.com
8-Oct-2007
Orderable Device
Status (1)
Package
Type
Package
Drawing
Pins Package Eco Plan (2)
Qty
TPS79533DCQG4
ACTIVE
SOT-223
DCQ
6
TPS79533DCQR
ACTIVE
SOT-223
DCQ
TPS79533DCQRG4
ACTIVE
SOT-223
DCQ
78
Lead/Ball Finish
MSL Peak Temp (3)
Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-2-260C-1 YEAR
6
2500 Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-2-260C-1 YEAR
6
2500 Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-2-260C-1 YEAR
(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)
Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check
http://www.ti.com/productcontent for the latest availability information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements
for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered
at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and
package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS
compatible) as defined above.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame
retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material)
(3)
MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder
temperature.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is
provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the
accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take
reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on
incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited
information may not be available for release.
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI
to Customer on an annual basis.
Addendum-Page 2
PACKAGE MATERIALS INFORMATION
www.ti.com
17-Apr-2009
TAPE AND REEL INFORMATION
*All dimensions are nominal
Device
Package Package Pins
Type Drawing
SPQ
Reel
Reel
Diameter Width
(mm) W1 (mm)
A0 (mm)
B0 (mm)
K0 (mm)
P1
(mm)
TPS79501DCQR
SOT-223
DCQ
6
2500
330.0
TPS79501DRBR
SON
DRB
8
3000
TPS79501DRBT
SON
DRB
8
250
TPS79516DCQR
SOT-223
DCQ
6
TPS79518DCQR
SOT-223
DCQ
TPS79525DCQR
SOT-223
TPS79530DCQR
SOT-223
TPS79533DCQR
SOT-223
12.4
6.8
7.3
1.88
8.0
12.0
Q3
330.0
12.4
3.3
3.3
1.1
8.0
12.0
Q2
180.0
12.4
3.3
3.3
1.1
8.0
12.0
Q2
2500
330.0
12.4
6.8
7.3
1.88
8.0
12.0
Q3
6
2500
330.0
12.4
6.8
7.3
1.88
8.0
12.0
Q3
DCQ
6
2500
330.0
12.4
6.8
7.3
1.88
8.0
12.0
Q3
DCQ
6
2500
330.0
12.4
6.8
7.3
1.88
8.0
12.0
Q3
DCQ
6
2500
330.0
12.4
6.8
7.3
1.88
8.0
12.0
Q3
Pack Materials-Page 1
W
Pin1
(mm) Quadrant
PACKAGE MATERIALS INFORMATION
www.ti.com
17-Apr-2009
*All dimensions are nominal
Device
Package Type
Package Drawing
Pins
SPQ
Length (mm)
Width (mm)
Height (mm)
TPS79501DCQR
SOT-223
DCQ
6
2500
358.0
335.0
35.0
TPS79501DRBR
SON
DRB
8
3000
346.0
346.0
29.0
TPS79501DRBT
SON
DRB
8
250
190.5
212.7
31.8
TPS79516DCQR
SOT-223
DCQ
6
2500
358.0
335.0
35.0
TPS79518DCQR
SOT-223
DCQ
6
2500
358.0
335.0
35.0
TPS79525DCQR
SOT-223
DCQ
6
2500
358.0
335.0
35.0
TPS79530DCQR
SOT-223
DCQ
6
2500
358.0
335.0
35.0
TPS79533DCQR
SOT-223
DCQ
6
2500
358.0
335.0
35.0
Pack Materials-Page 2
IMPORTANT NOTICE
Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements,
and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should
obtain the latest relevant information before placing orders and should verify that such information is current and complete. All products are
sold subject to TI’s terms and conditions of sale supplied at the time of order acknowledgment.
TI warrants performance of its hardware products to the specifications applicable at the time of sale in accordance with TI’s standard
warranty. Testing and other quality control techniques are used to the extent TI deems necessary to support this warranty. Except where
mandated by government requirements, testing of all parameters of each product is not necessarily performed.
TI assumes no liability for applications assistance or customer product design. Customers are responsible for their products and
applications using TI components. To minimize the risks associated with customer products and applications, customers should provide
adequate design and operating safeguards.
TI does not warrant or represent that any license, either express or implied, is granted under any TI patent right, copyright, mask work right,
or other TI intellectual property right relating to any combination, machine, or process in which TI products or services are used. Information
published by TI regarding third-party products or services does not constitute a license from TI to use such products or services or a
warranty or endorsement thereof. Use of such information may require a license from a third party under the patents or other intellectual
property of the third party, or a license from TI under the patents or other intellectual property of TI.
Reproduction of TI information in TI data books or data sheets is permissible only if reproduction is without alteration and is accompanied
by all associated warranties, conditions, limitations, and notices. Reproduction of this information with alteration is an unfair and deceptive
business practice. TI is not responsible or liable for such altered documentation. Information of third parties may be subject to additional
restrictions.
Resale of TI products or services with statements different from or beyond the parameters stated by TI for that product or service voids all
express and any implied warranties for the associated TI product or service and is an unfair and deceptive business practice. TI is not
responsible or liable for any such statements.
TI products are not authorized for use in safety-critical applications (such as life support) where a failure of the TI product would reasonably
be expected to cause severe personal injury or death, unless officers of the parties have executed an agreement specifically governing
such use. Buyers represent that they have all necessary expertise in the safety and regulatory ramifications of their applications, and
acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements concerning their products
and any use of TI products in such safety-critical applications, notwithstanding any applications-related information or support that may be
provided by TI. Further, Buyers must fully indemnify TI and its representatives against any damages arising out of the use of TI products in
such safety-critical applications.
TI products are neither designed nor intended for use in military/aerospace applications or environments unless the TI products are
specifically designated by TI as military-grade or "enhanced plastic." Only products designated by TI as military-grade meet military
specifications. Buyers acknowledge and agree that any such use of TI products which TI has not designated as military-grade is solely at
the Buyer's risk, and that they are solely responsible for compliance with all legal and regulatory requirements in connection with such use.
TI products are neither designed nor intended for use in automotive applications or environments unless the specific TI products are
designated by TI as compliant with ISO/TS 16949 requirements. Buyers acknowledge and agree that, if they use any non-designated
products in automotive applications, TI will not be responsible for any failure to meet such requirements.
Following are URLs where you can obtain information on other Texas Instruments products and application solutions:
Products
Applications
Amplifiers
amplifier.ti.com
Audio
www.ti.com/audio
Data Converters
dataconverter.ti.com
Automotive
www.ti.com/automotive
DLP® Products
www.dlp.com
Communications and
Telecom
www.ti.com/communications
DSP
dsp.ti.com
Computers and
Peripherals
www.ti.com/computers
Clocks and Timers
www.ti.com/clocks
Consumer Electronics
www.ti.com/consumer-apps
Interface
interface.ti.com
Energy
www.ti.com/energy
Logic
logic.ti.com
Industrial
www.ti.com/industrial
Power Mgmt
power.ti.com
Medical
www.ti.com/medical
Microcontrollers
microcontroller.ti.com
Security
www.ti.com/security
RFID
www.ti-rfid.com
Space, Avionics &
Defense
www.ti.com/space-avionics-defense
RF/IF and ZigBee® Solutions www.ti.com/lprf
Video and Imaging
www.ti.com/video
Wireless
www.ti.com/wireless-apps
Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265
Copyright © 2010, Texas Instruments Incorporated