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LP2989
SNVS083O – FEBRUARY 2005 – REVISED MARCH 2015
LP2989 Micropower and Low-Noise, 500-mA Ultra Low-Dropout Regulator for Use With
Ceramic Output Capacitors
1 Features
3 Description
•
•
•
•
•
•
•
•
•
•
•
The LP2989 is a fixed-output 500-mA precision LDO
regulator designed for use with ceramic output
capacitors.
1
2.1-V to 16-V Input Voltage Range
2.5-V to 5-V Fixed Output Voltage Options
Ultra-Low Dropout Voltage
500-mA Continuous Output Current
Very Low Output Noise With External Capacitor
< 0.8-µA Quiescent Current When Shutdown
Low Ground Pin Current at All Loads
0.75% Output Voltage Accuracy (A Grade)
High Peak Current Capability (800-mA typical)
Overtemperature and Overcurrent Protection
−40°C to 125°C Junction Temperature Range
2 Applications
•
•
•
•
Notebooks and Desktop PCs
PDAs and Palmtop Computers
Wireless Communication Pins
SMPS Post-Regulators
Output noise can be reduced to 18 μV (typical) by
connecting an external 10-nF capacitor to the bypass
pin.
Using an optimized Vertically Integrated PNP (VIP)
process, the LP2989 delivers superior performance:
• Dropout Voltage: Typically 310 mV at 500-mA
load, and 1 mV at 100-µA load.
• Ground Pin Current: Typically 3 mA at 500-mA
load, and 110 µA at 100-µA load.
• Sleep Mode: The LP2989 draws less than 0.8-µA
quiescent current when SHUTDOWN pin is pulled
low.
• Error Flag: The built-in error flag goes low when
the output drops approximately 5% below
nominal.
• Precision Output: Output voltage accuracy is
0.75% (A grade) and 1.25% (standard grade) at
room temperature.
For output voltages < 2 V, see LP2989LV (SNVS086)
data sheet.
Device Information(1)
PART NUMBER
LP2989
PACKAGE
BODY SIZE (NOM)
WSON (8)
4.00 mm x 4.00 mm
SOIC (8)
4.90 mm x 3.91 mm
VSSOP (8)
3.00 mm x 3.00 mm
(1) For all available packages, see the orderable addendum at
the end of the datasheet.
Typical Application
*Capacitance values shown are minimum required to assure stability, but may be increased without limit. Larger
output capacitor provides improved dynamic response. See the Output Capacitor section.
**Shutdown must be actively terminated (see the Shutdown Input Operation section). Tie to IN (pin 4) if not use.
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.
LP2989
SNVS083O – FEBRUARY 2005 – REVISED MARCH 2015
www.ti.com
Table of Contents
1
2
3
4
5
6
7
Features ..................................................................
Applications ...........................................................
Description .............................................................
Revision History.....................................................
Pin Configuration and Functions .........................
Specifications.........................................................
1
1
1
2
3
4
6.1
6.2
6.3
6.4
6.5
6.6
4
4
5
5
5
7
Absolute Maximum Ratings ......................................
ESD Ratings..............................................................
Recommended Operating Conditions.......................
Thermal Information ..................................................
Electrical Characteristics...........................................
Typical Characteristics ..............................................
Detailed Description ............................................ 14
7.1 Overview ................................................................. 14
7.2 Functional Block Diagram ....................................... 14
7.3 Feature Description................................................. 14
7.4 Device Functional Modes........................................ 15
8
Application and Implementation ........................ 16
8.1 Application Information............................................ 16
8.2 Typical Application ................................................. 16
9 Power Supply Recommendations...................... 20
10 Layout................................................................... 20
10.1 Layout Guidelines ................................................. 20
10.2 Layout Example .................................................... 20
11 Device and Documentation Support ................. 21
11.1
11.2
11.3
11.4
Documentation Support .......................................
Trademarks ...........................................................
Electrostatic Discharge Caution ............................
Glossary ................................................................
21
21
21
21
12 Mechanical, Packaging, and Orderable
Information ........................................................... 22
4 Revision History
Changes from Revision N (December 2014) to Revision O
Page
•
Changed 30-V to 16-V ........................................................................................................................................................... 1
•
Deleted trademark symbol from VIP which is no longer trademarked .................................................................................. 1
•
Changed pin names to TI nomenclature; references to National to TI; add notes to Typical Application on first page;
fix errors in EC table reformat; replace Handling Ratings with ESD Ratings; take out Output Voltage Options and
add graphic to Mechanical section; changed LLP package name references to WSON; added overbar to
SHUTDOWN pin references; fix ulink for LP2989LV references. .......................................................................................... 1
•
Changed description of N/C pin; add description of Thermal Pad; change "Ground" to "Thermal Pad" for NGN
drawing .................................................................................................................................................................................. 3
•
Changed reference to National to TI ..................................................................................................................................... 4
•
Deleted "Operating" row from Input supply voltage; thermal values from footnote 2 ............................................................ 4
•
Changed 1.6 to 16 in ROC input supply voltage ................................................................................................................... 5
•
Added word "OFF" ................................................................................................................................................................. 6
•
Changed "high" to "low" ....................................................................................................................................................... 14
•
Changed wording of "Operation with Shutdown Control" subsection ................................................................................. 15
•
Changed VON/OFF to VSD ....................................................................................................................................................... 15
•
Changed "guaranteed" to "ensured" in "CAUTION". ............................................................................................................ 15
•
Changed VON/OFF to VSD ....................................................................................................................................................... 15
•
Changed wording of last sentence of introductory Detailed Design Procedure paragraph ................................................ 17
•
Changed words "size" and "amount" for capacitors to "value" ............................................................................................ 17
•
Changed wording of first sentence, second paragraph of Noise Bypass Capacitor subsection ......................................... 18
•
Added Documentation Support section ............................................................................................................................... 21
Changes from Revision M (February 2005) to Revision N
•
2
Page
Added Handling Rating table, Feature Description section, Device Functional Modes, Application and
Implementation section, Power Supply Recommendations section, Layout section, Device and Documentation
Support section, and Mechanical, Packaging, and Orderable Information section; add updated Thermal Information
values .................................................................................................................................................................................... 1
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5 Pin Configuration and Functions
D/DGK Packages
8-Pin SOIC and VSSOP
Top View
NGN Package
8-Lead WSON
Top View
Pin Functions
PIN
NAME
NO.
BYPASS
1
ERROR
GROUND
INPUT
I/O
DESCRIPTION
I
Bypass capacitor input
7
O
Error signal output
3
—
GND
4
I
Regulator power input
N/C
2
—
DO NOT CONNECT. Device pin 2 is reserved for post packaging test and calibration of the
LP2989 VOUT accuracy. Device pin 2 must be left floating. Do not connect to any potential.
Do not connect to ground. Any attempt to do pin continuity testing on device pin 2 is
discouraged. Continuity test results will be variable depending on the actions of the factory
calibration. Aggressive pin continuity testing (high voltage, or high current) on device pin 2
may activate the trim circuitry forcing VOUT to move out of tolerance.
OUTPUT
5
O
Regulated output voltage
SENSE
6
I
Feedback voltage sense input
SHUTDOWN
8
I
Shutdown input
Thermal Pad
—
—
The exposed thermal pad on the bottom of the WSON package should be connected to a
copper thermal pad on the PCB under the package. The use of thermal vias to remove heat
from the package into the PCB is recommended. Connect the thermal pad to ground
potential or leave floating. Do not connect the thermal pad to any potential other than the
same ground potential seen at device pin 3. For additional information on using TI's Non Pull
Back WSON package, see Application Note AN-1187 Leadless Leadframe Package (LLP)
(SNOA401).
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6 Specifications
6.1 Absolute Maximum Ratings
If Military/Aerospace specified devices are required contact the Texas Instruments Sales Office/Distributors for availability and
specifications. (1)
Operating junction temperature
Power dissipation
Output voltage
Survival (3)
IOUT (Survival)
Input-output voltage
(4)
°C
–0.3
16
V
–0.3
6
V
–0.3
16
V
Short-circuit protected
Survival (4)
Storage temperature range, Tstg
(3)
UNIT
125
Internally Limited
Survival
SENSE pin
(2)
MAX
–40
(2)
Input supply voltage
(1)
MIN
–0.3
16
V
–65
150
°C
Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings
only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended
Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
The maximum allowable power dissipation is a function of the maximum junction temperature, TJ(MAX), the junction-to-ambient thermal
resistance, RθJA, and the ambient temperature, TA. The maximum allowable power dissipation at any ambient temperature is calculated
using: P(MAX) = (TJ(MAX) – TA) / RθJA. The value RθJA for the WSON (NGN) package is specifically dependent on PCB trace area, trace
material, and the number of layers and thermal vias. For improved thermal resistance and power dissipation for the WSON package,
refer to Application Note AN-1187 Leadless Leadframe Package (LLP) (SNOA401).. Exceeding the maximum allowable power
dissipation will cause excessive die temperature, and the regulator will go into thermal shutdown.
If used in a dual-supply system where the regulator load is returned to a negative supply, the LP2989 output must be diode-clamped to
ground.
The output PNP structure contains a diode between the IN and OUT pins that is normally reverse-biased. Forcing the output above the
input will turn on this diode and may induce a latch-up mode which can damage the part.
6.2 ESD Ratings
V(ESD)
(1)
4
Electrostatic discharge
Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001 (1)
VALUE
UNIT
±2000
V
JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
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6.3 Recommended Operating Conditions
over operating free-air temperature range (unless otherwise noted)
MIN
MAX
UNIT
Operating junction temperature
–40
125
°C
Operating input supply voltage
2.1
16
V
6.4 Thermal Information
LP2989
THERMAL METRIC (1)
WSON (NGN)
SOIC (D)
VSSOP (DGK)
8 PINS
8 PINS
8 PINS
RθJA
Junction-to-ambient thermal resistance, High-K
34.8
114.5
156.5
RθJC(top)
Junction-to-case (top) thermal resistance
28.4
61.1
51.0
RθJB
Junction-to-board thermal resistance
12.0
55.6
76.5
ψJT
Junction-to-top characterization parameter
0.2
9.7
4.9
ψJB
Junction-to-board characterization parameter
12.2
54.9
75.2
RθJC(bot)
Junction-to-case (bottom) thermal resistance
1.3
n/a
n/a
(1)
UNIT
°C/W
For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953.
6.5 Electrical Characteristics
Unless otherwise specified: TJ = 25°C, VIN = VOUT(NOM) + 1 V, IOUT = 1 mA, COUT = 4.7 µF, CIN = 2.2 µF, VSD = 2 V.
PARAMETER
VOUT
ΔVOUT/ΔVIN
ΔVOUT/ΔIOUT
VIN – VOUT
(1)
(2)
Output voltage tolerance
Output voltage line
regulation
Load regulation
Dropout voltage (2)
TEST CONDITIONS
LP2989AI-X.X (1)
MIN
TYP
LP2989I-X.X (1)
MAX
MIN
TYP
−0.75
0.75
−1.25
1.25
1 mA < IOUT < 500 mA,
VOUT(NOM) + 1 V ≤ VIN ≤ 16
V
−1.5
1.5
−2.5
2.5
1 mA < IOUT < 500 mA,
VOUT(NOM) + 1 V ≤ VIN ≤ 16
V, –40°C ≤ TJ ≤ 125°C
−4
2.5
−5
3.5
1 mA < IOUT < 500 mA,
VOUT(NOM) + 1 V ≤ VIN ≤ 16
V, −25°C ≤ TJ ≤ 125°C
−3.5
2.5
−4.5
3.5
VOUT(NOM) + 1 V ≤ VIN ≤ 16
V
0.005
0.014
0.005
0.014
VOUT(NOM) + 1 V ≤ VIN ≤ 16
V, –40°C ≤ TJ ≤ 125°C
0.005
0.032
0.005
0.032
1 mA < IOUT < 500 mA
UNIT
MAX
%VNOM
%/V
0.4
0.4
%VNOM
IOUT = 100 µA
1
3
1
3
IOUT = 100 µA, –40°C ≤ TJ ≤
125°C
1
4
1
4
IOUT = 200 mA
150
200
150
200
IOUT = 200 mA, –40°C ≤ TJ
≤ 125°C
150
300
150
300
IOUT = 500 mA
310
425
310
425
IOUT = 500 mA, –40°C ≤ TJ
≤ 125°C
310
650
310
650
mV
mV
mV
Limits are 100% production tested at 25°C. Limits over the operating temperature range are specified through correlation using
Statistical Quality Control (SQC) methods. The limits are used to calculate TI’s Average Outgoing Quality Level (AOQL).
Dropout voltage is defined as the input to output differential at which the output voltage drops 100 mV below the value measured with a
1-V differential.
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Electrical Characteristics (continued)
Unless otherwise specified: TJ = 25°C, VIN = VOUT(NOM) + 1 V, IOUT = 1 mA, COUT = 4.7 µF, CIN = 2.2 µF, VSD = 2 V.
PARAMETER
IGND
Ground pin current
TEST CONDITIONS
LP2989AI-X.X (1)
MIN
TYP
MAX
TYP
MAX
IOUT = 100 µA
110
IOUT = 100 µA, –40°C ≤ TJ ≤
125°C
175
110
175
110
200
110
200
IOUT= 200 mA
1
2
1
2
IOUT = 200 mA, –40°C ≤ TJ
≤ 125°C
1
3.5
1
3.5
IOUT = 500 mA
3
6
3
6
IOUT = 500 mA, –40°C ≤ TJ
≤ 125°C
3
9
3
9
VSD < 0.18 V, –40°C ≤ TJ ≤
125°C
0.5
2
0.5
2
0.05
0.8
0.05
0.8
VSD < 0.4 V
Peak output current
VOUT ≥ VOUT(NOM) − 5%
Short circuit current
RL = 0 (Steady State)
(3)
en
Output noise voltage
(RMS)
BW = 100 Hz to 100 kHz,
COUT = 10 µF, CBYPASS =
.01 µF, VOUT = 2.5 V
ΔVOUT/ΔVIN
Ripple Rejection
f = 1 kHz, COUT = 10 µF
ΔVOUT/ΔTD
Output voltage
temperature coefficient
IOUT(PK)
IOUT(MAX)
LP2989I-X.X (1)
See
600
(4)
, –40°C ≤ TJ ≤ 125°C
800
MIN
600
UNIT
µA
mA
mA
µA
800
mA
1000
1000
mA
18
18
µV(RMS)
60
60
dB
20
20
ppm/°C
1.4
1.4
SHUTDOWN INPUT
VH = Output ON
VSD
SD Input voltage
VH = Output ON, –40°C ≤ TJ
≤ 125°C
1.6
VL = Output OFF
1.6
0.5
VL = Output OFF, IIN ≤ 2 µA,
–40°C ≤ TJ ≤ 125°C
0.18
VSD = 0
ISD
SD Input current
0.18
0.001
VSD = 0, –40°C ≤ TJ ≤
125°C
0.001
−1
VSD = 5 V
−1
5
VSD = 5 V, –40°C ≤ TJ ≤
125°C
V
0.5
µA
5
15
15
ERROR COMPARATOR
IOH
Output “HIGH” leakage
VOL
Output “LOW” voltage
VTHR(MAX)
Upper threshold voltage
VTHR(MIN)
Lower threshold voltage
HYST
Hysteresis
(3)
(4)
6
VOH = 16 V
0.001
1
0.001
1
VOH = 16 V, –40°C ≤ TJ ≤
125°C
0.001
2
0.001
2
VIN = VOUT(NOM) − 0.5 V,
IOUT(COMP) = 150 µA
150
220
150
220
VIN = VOUT(NOM) − 0.5 V,
IOUT(COMP) = 150 µA, –40°C
≤ TJ ≤ 125°C
150
350
150
350
–40°C ≤ TJ ≤ 125°C
–40°C ≤ TJ ≤ 125°C
µA
mV
−6
−4.8
−3.5
−6
−4.8
−3.5
−8.3
−4.8
−2.5
−8.3
−4.8
−2.5
−8.9
−6.6
−4.9
−8.9
−6.6
−4.9
−13
−6.6
−3
−13
−6.6
%VOUT
−3 %VOUT
2
See the Typical Characteristics section.
Temperature coefficient is defined as the maximum (worst-case) change divided by the total temperature range.
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6.6 Typical Characteristics
TA = 25°C, COUT = 4.7 µF, CIN = 2.2 µF, SD is tied to VIN, VIN = VOUT(NOM)+ 1 V, IOUT = 1 mA, VOUT = 2.5 V (unless otherwise
specified)
Figure 1. Dropout Characteristics
Figure 2. Dropout Voltage vs Temperature
Figure 3. Dropout Voltage vs Load Current
Figure 4. GND Pin Current vs Temperature and Load
Figure 5. Ground Pin Current vs Load Current
Figure 6. Input Current vs VIN
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Typical Characteristics (continued)
TA = 25°C, COUT = 4.7 µF, CIN = 2.2 µF, SD is tied to VIN, VIN = VOUT(NOM)+ 1 V, IOUT = 1 mA, VOUT = 2.5 V (unless otherwise
specified)
8
Figure 7. Input Current vs VIN
Figure 8. Input Current vs VIN
Figure 9. Line Transient Response
Figure 10. Line Transient Response
Figure 11. Line Transient Response
Figure 12. Line Transient Response
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Typical Characteristics (continued)
TA = 25°C, COUT = 4.7 µF, CIN = 2.2 µF, SD is tied to VIN, VIN = VOUT(NOM)+ 1 V, IOUT = 1 mA, VOUT = 2.5 V (unless otherwise
specified)
Figure 13. Load Transient Response
Figure 14. Load Transient Response
Figure 15. Short Circuit Current
Figure 16. Short Circuit Current vs Temperature
Figure 17. Short Circuit Current
Figure 18. Short Circuit Current vs VOUT
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Typical Characteristics (continued)
TA = 25°C, COUT = 4.7 µF, CIN = 2.2 µF, SD is tied to VIN, VIN = VOUT(NOM)+ 1 V, IOUT = 1 mA, VOUT = 2.5 V (unless otherwise
specified)
10
Figure 19. Ripple Rejection
Figure 20. Ripple Rejection
Figure 21. Ripple Rejection
Figure 22. Ripple Rejection
Figure 23. Ripple Rejection
Figure 24. Ripple Rejection
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Typical Characteristics (continued)
TA = 25°C, COUT = 4.7 µF, CIN = 2.2 µF, SD is tied to VIN, VIN = VOUT(NOM)+ 1 V, IOUT = 1 mA, VOUT = 2.5 V (unless otherwise
specified)
Figure 25. Ripple Rejection
Figure 26. Ripple Rejection in Dropout
Figure 27. Ripple Rejection vs Load
Figure 28. Output Noise Density
Figure 29. Output Noise Density
Figure 30. Turn-ON Waveform
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Typical Characteristics (continued)
TA = 25°C, COUT = 4.7 µF, CIN = 2.2 µF, SD is tied to VIN, VIN = VOUT(NOM)+ 1 V, IOUT = 1 mA, VOUT = 2.5 V (unless otherwise
specified)
12
Figure 31. Turn-ON Waveform
Figure 32. Turn-ON Waveform
Figure 33. Turn-ON Waveform
Figure 34. IGND vs Shutdown
Figure 35. IGND vs Shutdown
Figure 36. IGND vs Shutdown
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Typical Characteristics (continued)
TA = 25°C, COUT = 4.7 µF, CIN = 2.2 µF, SD is tied to VIN, VIN = VOUT(NOM)+ 1 V, IOUT = 1 mA, VOUT = 2.5 V (unless otherwise
specified)
Figure 38. VOUT vs Shutdown
Figure 37. IGND vs Shutdown
Figure 39. Typical Temperature vs VOUT (LP2989-2.5)
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7 Detailed Description
7.1 Overview
The LP2989 device is a very high-accuracy micro-power voltage regulator with low quiescent current (75 μA
typical) and low dropout voltage (typical 40 mV at light loads and 380 mV at 100 mA). It is ideally suited for use
in battery-powered systems. The LP2989 block diagram contains several features, including:
• Very high-accuracy 1.23-V reference
• Fixed 2.5-V to 5-V versions
• Shutdown input
• Error flag output
• Internal protection circuitry, such as foldback current limit, and thermal shutdown
7.2 Functional Block Diagram
7.3 Feature Description
7.3.1 High-Accuracy Output Voltage
With special careful design to minimize all contributions to the output voltage error, the LP2989 distinguishes
itself as a very high output-voltage-accuracy micro-power LDO. This includes a tight initial tolerance (.75%
typical, A grade), extremely good line regulation (.005%/V typical), and a very low output-noise voltage (10 µVRMS
typical), making the device an ideal a low-power voltage reference.
7.3.2 Sleep Mode
When pulling SHUTDOWN pin to low levels, the LP2989 enters shutdown mode, and a very low quiescent
current is consumed. This function is designed for applications which needs a shutdown mode to effectively
enhance battery life cycle.
7.3.3 Error Detection Comparator Output
The LP2989 will generate a logic low output whenever its output falls out of regulation by more than
approximately 5%. Refer to Application and Implementation for more details.
14
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Feature Description (continued)
7.3.4 Short Circuit Protection (Current Limit)
The internal current limit circuit is used to protect the LDO against high-load current faults or shorting events. The
LDO is not designed to operate in a steady-state current limit. During a current-limit event, the LDO sources
constant current. Therefore, the output voltage falls when load impedance decreases. Note also that if a current
limit occurs and the resulting output voltage is low, excessive power may be dissipated across the LDO, resulting
in a thermal shutdown of the output. A foldback feature limits the short-circuit current to protect the regulator from
damage under all load conditions. If OUT is forced below 0 V before EN goes high and the load current required
exceeds the foldback current limit, the device may not start correctly.
7.3.5 Thermal Protection
The device contains a thermal shutdown protection circuit to turn off the output current when excessive heat is
dissipated in the LDO. The thermal time-constant of the semiconductor die is fairly short, and thus the output
cycles on and off at a high rate when thermal shutdown is reached until the power dissipation is reduced. The
internal protection circuitry of the device is designed to protect against thermal overload conditions. The circuitry
is not intended to replace proper heat sinking. Continuously running the device into thermal shutdown degrades
its reliability.
7.4 Device Functional Modes
7.4.1 Operation With 16 V ≥ VIN > VOUT(TARGET) + 1 V
The device operates if the input voltage is equal to, or exceeds VOUT(TARGET) + 1 V. At input voltages below the
minimum VIN requirement, the devices does not operate correctly, and output voltage may not reach target value.
7.4.2 Operation with Shutdown Control
If the voltage on the SHUTDOWN pin is less than 0.18 V, the output is ensured to be OFF. When the voltage on
the SHUTDOWN pin is more than 1.6 V the output is ensured to be ON. Operating with the SHUTDOWN pin
voltage between 0.18 V and 1.6 V is strongly discouraged as the status of the output is not ensured.
7.4.3 Shutdown Input Operation
The LP2989 is shut off by driving the SHUTDOWN pin low, and turned on by pulling it high. If this feature is not
to be used, the SHUTDOWN should be tied to VIN to keep the regulator output on at all times.
To assure proper operation, the signal source used to drive the Shutdown input must be able to swing above and
below the specified turn-on/turn-off voltage thresholds listed in the Electrical Characteristics section under VSD.
To prevent mis-operation, the turn-on (and turn-off) voltage signals applied to the Shutdown input must have a
slew rate which is ≥ 40 mV/µs.
CAUTION
The regulator output voltage cannot be ensured if a slow-moving AC (or DC) signal is
applied that is in the range between the specified turn-on and turn-off voltages listed
under the electrical specification VSD (see the Electrical Characteristics table).
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8 Application and Implementation
NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
8.1 Application Information
The LP2989 is a linear voltage regulator operating from 2.1 V to 16 V on the input and regulates voltages
between 2.5 V to 5 V with 0.75% accuracy and 500 mA maximum outputs current. Efficiency is defined by the
ratio of output voltage to input voltage because the LP2989 is a linear voltage regulator. To achieve high
efficiency, the dropout voltage (VIN – VOUT) must be as small as possible, thus requiring a very low dropout LDO.
Successfully implementing an LDO in an application depends on the application requirements. If the
requirements are simply input voltage and output voltage, compliance specifications (such as internal power
dissipation or stability) must be verified to ensure a solid design. If timing, start-up, noise, PSRR, or any other
transient specification is required, the design becomes more challenging. This section discusses the
implementation and behavior of the LP2989 LDO.
8.2 Typical Application
*Capacitance values shown are minimum required to assure stability, but may be increased without limit. Larger
output capacitor provides improved dynamic response. See the Output Capacitor section.
**Shutdown must be actively terminated (see the Shutdown Input Operation section). Tie to IN (pin 4) if not use.
Figure 40. Typical Application Schematic
8.2.1 Design Requirements
16
DESIGN PARAMETER
DESIGN REQUIREMENT
Input voltage
6.5 V, ±10%,
Output voltage
5 V, ±1%
Output current
500 mA (maximum), 1 mA (minimum)
RMS noise, 100 Hz to 100 kHz
18 μVRMS typical
PSRR at 1 kHz
60 dB typical
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8.2.2 Detailed Design Procedure
At 500-mA loading, the dropout of the LP2989 has 650-mV maximum dropout over temperature, thus an 1500mV headroom is sufficient for operation over both input and output voltage accuracy. The efficiency of the
LP2989 in this configuration is VOUT / VIN = 76.9%. To achieve the smallest form factor, the WSON package is
selected. Input and output capacitors are selected in accordance with the capacitor recommendations. Ceramic
capacitances of 2.2 μF for the input and one 4.7-μF capacitor for the output are selected. With an efficiency of
76.9% and a 500-mA maximum load, the internal power dissipation is 750 mW, which corresponds to a 26.1°C
junction temperature rise for the WSON package. With an 85°C maximum ambient temperature, the junction
temperature is at 111.1°C. To minimize noise, a bypass capacitance (CBYPASS) of 0.01 µF is placed from the
BYPASS pin (device pin 1) to device ground (device pin 3).
8.2.2.1 WSON Package Devices
The LP2989 is offered in the 8-lead WSON surface mount package to allow for increased power dissipation
compared to the SOIC and VSSOP packages. For details on thermal performance as well as mounting and
soldering specifications, refer to Application Note AN-1187 Leadless Leadframe Package (LLP) (SNOA401).
For output voltages < 2 V, see LP2989LV (SNVS086) data sheet.
8.2.2.2 External Capacitors
Like any low-dropout regulator, the LP2989 requires external capacitors for regulator stability. These capacitors
must be correctly selected for good performance.
8.2.2.2.1 Input Capacitor
An input capacitor whose value is at least 2.2 µF is required between the LP2989 input and ground (the amount
of capacitance may be increased without limit).
Characterization testing performed on the LP2989 has shown that if the value of actual input capacitance drops
below about 1.5 µF, an unstable operating condition may result. Therefore, the next larger standard size (2.2 µF)
is specified as the minimum required input capacitance. Capacitor tolerance and temperature variation must be
considered when selecting a capacitor (see Capacitor Characteristics section) to assure the minimum
requirement of 1.5 µF is met over all operating conditions.
The input capacitor must be located at a distance of not more than 0.5 inches from the input pin and returned to
a clean analog ground. Any good quality ceramic or tantalum may be used for this capacitor, assuming the
minimum capacitance requirement is met.
8.2.2.2.2 Output Capacitor
The LP2989 requires a ceramic output capacitor whose value is at least 4.7 µF. The actual amount of
capacitance on the output must never drop below about 3.5 µF or unstable operation may result. For this reason,
capacitance tolerance and temperature characteristics must be considered when selecting an output capacitor.
The LP2989 is designed specifically to work with ceramic output capacitors, using circuitry which allows the
regulator to be stable across the entire range of output current with an output capacitor whose ESR is as low as
4 mΩ. It may also be possible to use Tantalum or film capacitors at the output, but these are not as attractive for
reasons of size and cost (see the Capacitor Characteristics section).
The output capacitor must meet the requirement for minimum amount of capacitance and also have an
equivalent series resistance (ESR) value which is within the stable range. Curves are provided which show the
stable ESR range as a function of load current (see Figure 41).
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Figure 41. Stable Region for Output Capacitor ESR
NOTE
Important: The output capacitor must maintain its ESR within the stable region over the
full operating temperature range of the application to assure stability.
It is important to remember that capacitor tolerance and variation with temperature must be considered when
selecting an output capacitor so that the minimum required amount of output capacitance is provided over the full
operating temperature range. (See the Capacitor Characteristics section.)
The output capacitor must be located not more than 0.5 inches from the OUT pin and returned to a clean analog
ground.
8.2.2.2.3 Noise Bypass Capacitor
Connecting a 10-nF capacitor to the BYPASS pin significantly reduces noise on the regulator output. However,
the capacitor is connected directly to a high-impedance circuit in the bandgap reference.
Because this circuit has only a few microamperes flowing in it, any significant loading on this node will cause the
regulated output voltage to drop. For this reason, DC leakage current through the noise bypass capacitor must
never exceed 100 nA, and should be kept as low as possible for best output voltage accuracy.
The types of capacitors best suited for the noise bypass capacitor are ceramic and film. High-quality ceramic
capacitors with either NPO or COG dielectric typically have very low leakage. Ten-nF polypropolene and
polycarbonate film capacitors are available in small surface-mount packages and typically have extremely low
leakage current.
8.2.2.3 Capacitor Characteristics
8.2.2.3.1 Ceramic
The LP2989 was designed to work with ceramic capacitors on the output to take advantage of the benefits they
offer: for capacitance values in the 4.7 µF range, ceramics are the least expensive and also have the lowest ESR
values (which makes them best for eliminating high-frequency noise). The ESR of a typical 4.7-µF ceramic
capacitor is in the range of 10 mΩ to 15 mΩ, which easily meets the ESR limits required for stability by the
LP2989.
One disadvantage of ceramic capacitors is that their capacitance can vary with temperature. Many large-value
ceramic capacitors (≥ 2.2 µF) are manufactured with the Z5U or Y5V temperature characteristic, which results in
the capacitance dropping by more than 50% as the temperature goes from 25°C to 85°C.
This could cause problems if a 4.7-µF capacitor were used on the output because it will drop down to
approximately 2.4 µF at high ambient temperatures (which could cause the LP2989 to oscillate). Another
significant problem with Z5U and Y5V dielectric devices is that the capacitance drops severely with applied
voltage. A typical Z5U or Y5V capacitor can lose 60% of its rated capacitance with half of the rated voltage
applied to it.
18
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For these reasons, X7R and X5R type ceramic capacitors must be used on the input and output of the LP2989.
8.2.2.3.2 Tantalum
Tantalum capacitors are less desirable than ceramics for use as output capacitors because they are typically
more expensive when comparing equivalent capacitance and voltage ratings in the 1 µF to 4.7 µF range.
Another important consideration is that Tantalum capacitors have higher ESR values than equivalent size
ceramics; while it may be possible to find a Tantalum capacitor with an ESR value within the stable range, it
would have to be larger in capacitance (which means bigger and more costly) than a ceramic capacitor with the
same ESR value.
It should also be noted that the ESR of a typical Tantalum will increase about 2:1 as the temperature goes from
25°C down to −40°C, so some guard band must be allowed.
Tantalum capacitors may be used on the input as long as the requirement for minimum capacitance is met.
8.2.2.3.3 Film
Polycarbonate and polypropelene film capacitors have excellent electrical performance: their ESR is the lowest of
the three types listed, their capacitance is very stable with temperature, and DC leakage current is extremely low.
One disadvantage is that film capacitors are larger in physical size than ceramic or tantalum which makes film a
poor choice for either input or output capacitors.
However, their low leakage makes them a good choice for the noise bypass capacitor. Because the required
amount of capacitance is only 0.01 µF, small surface-mount film capacitors are available in this size.
8.2.2.4 Reverse Input-Output Voltage
The PNP power transistor used as the pass element in the LP2989 has an inherent diode connected between
the regulator output and input.
During normal operation (where the input voltage is higher than the output) this diode is reverse-biased.
However, if the output is pulled above the input, this diode will turn on and current will flow into the regulator
output.
In such cases, a parasitic SCR can latch which will allow high current to flow into VIN can damage the part.
In any application where the output may be pulled above the input, an external Schottky diode must be
connected from VIN to VOUT (cathode on VIN, anode on VOUT), to limit the reverse voltage across the LP2989 to
0.3 V (see the Absolute Maximum Ratings table).
8.2.3 Application Curves
Figure 42. Line Transient Response
Figure 43. Load Transient Response
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9 Power Supply Recommendations
The LP2989 is designed to operate from an input voltage supply range from 2.1 V to 16 V. The input voltage
range provides adequate headroom for the device to have a regulated output. This input supply must be well
regulated. If the input supply is noisy, additional input capacitors with low ESR can help improve the output noise
performance.
10 Layout
10.1 Layout Guidelines
For best overall performance, place all circuit components on the same side of the circuit board and as near as
practical to the respective LDO pin connections. Place ground return connections to the input and output
capacitor, and to the LDO ground pin as close to each other as possible, connected by a wide, component-side,
copper surface. The use of vias and long traces to create LDO circuit connections is strongly discouraged and
negatively affects system performance. This grounding and layout scheme minimizes inductive parasitics, and
thereby reduces load-current transients, minimizes noise, and increases circuit stability. A ground reference
plane is also recommended and is either embedded in the PCB itself or located on the bottom side of the PCB
opposite the components. This reference plane serves to assure accuracy of the output voltage, shield noise,
and behaves similar to a thermal plane to spread (or sink) heat from the LDO device. In most applications, this
ground plane is necessary to meet thermal requirements.
10.2 Layout Example
BYPASS
SHUTDOWN
Error Pullup
Resistor
N/C
VOUT
ERROR
Ground
GROUND
SENSE
IN
OUT
Input
Capacitor
VOUT
VIN
Output
Capacitor
Figure 44. Layout Example
20
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11 Device and Documentation Support
11.1 Documentation Support
11.1.1 Related Documentation
For related documentation see the following:
LP2989LV (SNVS086) data sheet
Application Note AN-1187 Leadless Leadframe Package (LLP) (SNOA401).
11.2 Trademarks
All trademarks are the property of their respective owners.
11.3 Electrostatic Discharge Caution
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
11.4 Glossary
SLYZ022 — TI Glossary.
This glossary lists and explains terms, acronyms, and definitions.
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12 Mechanical, Packaging, and Orderable Information
The following pages include mechanical, packaging, and orderable information. This information is the most
current data available for the designated devices. This data is subject to change without notice and revision of
this document. For browser-based versions of this data sheet, refer to the left-hand navigation.
Figure 45. POA Orderable Device Key
22
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PACKAGE OPTION ADDENDUM
www.ti.com
10-Dec-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)
LP2989AILD-3.0/NOPB
ACTIVE
WSON
NGN
8
1000
RoHS & Green
SN
Level-3-260C-168 HR
-40 to 125
L01HA
Samples
LP2989AILD-3.3/NOPB
ACTIVE
WSON
NGN
8
1000
RoHS & Green
SN
Level-3-260C-168 HR
-40 to 125
L01JA
Samples
LP2989AILD-5.0/NOPB
ACTIVE
WSON
NGN
8
1000
RoHS & Green
SN
Level-3-260C-168 HR
-40 to 125
L01KA
Samples
LP2989AIM-2.5/NOPB
ACTIVE
SOIC
D
8
95
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
2989A
IM2.5
Samples
LP2989AIM-3.0/NOPB
LIFEBUY
SOIC
D
8
95
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
2989A
IM3.0
LP2989AIM-3.3/NOPB
LIFEBUY
SOIC
D
8
95
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
2989A
IM3.3
LP2989AIM-5.0
NRND
SOIC
D
8
95
Non-RoHS
& Green
Call TI
Level-1-235C-UNLIM
-40 to 125
2989A
IM5.0
LP2989AIM-5.0/NOPB
ACTIVE
SOIC
D
8
95
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
2989A
IM5.0
LP2989AIMM-2.5/NOPB
LIFEBUY
VSSOP
DGK
8
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
LA0A
LP2989AIMM-3.0/NOPB
ACTIVE
VSSOP
DGK
8
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
LA1A
LP2989AIMM-3.3/NOPB
LIFEBUY
VSSOP
DGK
8
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
LA2A
LP2989AIMM-5.0/NOPB
ACTIVE
VSSOP
DGK
8
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
LA4A
LP2989AIMMX-2.5/NOPB
LIFEBUY
VSSOP
DGK
8
3500
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
LA0A
LP2989AIMMX-5.0/NOPB
ACTIVE
VSSOP
DGK
8
3500
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
LA4A
LP2989AIMX-2.5/NOPB
LIFEBUY
SOIC
D
8
2500
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
2989A
IM2.5
LP2989AIMX-3.0/NOPB
ACTIVE
SOIC
D
8
2500
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
2989A
IM3.0
Samples
LP2989AIMX-3.3/NOPB
ACTIVE
SOIC
D
8
2500
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
2989A
IM3.3
Samples
LP2989AIMX-5.0/NOPB
LIFEBUY
SOIC
D
8
2500
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
2989A
IM5.0
LP2989ILD-2.5/NOPB
LIFEBUY
WSON
NGN
8
1000
RoHS & Green
SN
Level-3-260C-168 HR
-40 to 125
L01FA
B
Addendum-Page 1
Samples
Samples
Samples
Samples
PACKAGE OPTION ADDENDUM
www.ti.com
Orderable Device
10-Dec-2022
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)
(1)
LP2989ILD-3.0/NOPB
LIFEBUY
WSON
NGN
8
1000
RoHS & Green
SN
Level-3-260C-168 HR
-40 to 125
L01HA
B
LP2989ILD-3.3/NOPB
ACTIVE
WSON
NGN
8
1000
RoHS & Green
SN
Level-3-260C-168 HR
-40 to 125
L01JA
B
LP2989ILD-5.0/NOPB
LIFEBUY
WSON
NGN
8
1000
RoHS & Green
SN
Level-3-260C-168 HR
-40 to 125
L01KA
B
LP2989ILDX-3.3/NOPB
ACTIVE
WSON
NGN
8
4500
RoHS & Green
SN
Level-3-260C-168 HR
-40 to 125
L01JA
B
Samples
LP2989ILDX-5.0/NOPB
ACTIVE
WSON
NGN
8
4500
RoHS & Green
SN
Level-3-260C-168 HR
-40 to 125
L01KA
B
Samples
LP2989IM-2.5/NOPB
LIFEBUY
SOIC
D
8
95
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
2989
IM2.5
LP2989IM-3.0/NOPB
ACTIVE
SOIC
D
8
95
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
2989
IM3.0
LP2989IM-3.3/NOPB
LIFEBUY
SOIC
D
8
95
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
2989
IM3.3
LP2989IM-5.0/NOPB
LIFEBUY
SOIC
D
8
95
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
2989
IM5.0
LP2989IMM-2.8/NOPB
ACTIVE
VSSOP
DGK
8
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
LA6B
Samples
LP2989IMM-3.0/NOPB
ACTIVE
VSSOP
DGK
8
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
LA1B
Samples
LP2989IMM-3.3/NOPB
LIFEBUY
VSSOP
DGK
8
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
LA2B
LP2989IMM-5.0/NOPB
ACTIVE
VSSOP
DGK
8
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
LA4B
Samples
LP2989IMMX-2.8/NOPB
ACTIVE
VSSOP
DGK
8
3500
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
LA6B
Samples
LP2989IMMX-5.0/NOPB
ACTIVE
VSSOP
DGK
8
3500
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
LA4B
Samples
LP2989IMX-2.5/NOPB
LIFEBUY
SOIC
D
8
2500
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
2989
IM2.5
LP2989IMX-3.3/NOPB
LIFEBUY
SOIC
D
8
2500
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
2989
IM3.3
LP2989IMX-5.0/NOPB
ACTIVE
SOIC
D
8
2500
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
2989
IM5.0
The marketing status values are defined as follows:
Addendum-Page 2
Samples
Samples
Samples
PACKAGE OPTION ADDENDUM
www.ti.com
10-Dec-2022
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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