TI1 LP3981IMM-3.3 Micropower, 300-ma ultra-low-dropout cmos voltage regulator Datasheet

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LP3981
SNVS159H – OCTOBER 2001 – REVISED JULY 2015
LP3981 Micropower, 300-mA Ultra-Low-Dropout CMOS Voltage Regulator
1 Features
3 Description
•
•
•
•
•
Performance of the LP3981 device is optimized for
battery-powered systems to deliver ultra-low-noise,
extremely low dropout voltage, and low quiescent
current. Regulator ground current increases only
slightly in dropout, further prolonging the battery life.
1
•
•
•
•
•
•
2.5-V to 6-V Input Range
300-mA Output Current
60-dB PSRR at 1 kHz
≤ 1-μA Quiescent Current When Shut Down
Fast Turnon Time: 120 μs (typical) with CBYPASS =
0.01 µF
132-mV Typical Dropout with 300-mA Load
35-μVrms Output Noise Over 10 Hz to 100 kHz
Logic Controlled Enable
Stable With Ceramic and High-Quality Tantalum
Capacitors
Thermal Shutdown and Short-Circuit Current Limit
Low Thermal Resistance in WSON-6 Package
Gives Excellent Power Capability
Power supply rejection is better than 60 dB at low
frequencies. This high power supply rejection is
maintained down to lower input voltage levels
common to battery-operated circuits.
The device is ideal for mobile phone and similar
battery-powered wireless applications. It provides up
to 300 mA, from a 2.5-V to 6-V input, consuming less
than 1 µA in disable mode.
The LP3981 is available in 8-pin VSSOP-8 and 6-pin
WSON packages. Performance is specified for −40°C
to +125°C temperature range. The device available in
the following output voltages: 2.5 V, 2.7 V, 2.8 V,
2.83 V, 3 V, 3.03 V and 3.3 V as standard. Other
output options can be made available; contact your
local TI sales office for more information.
2 Applications
•
•
•
•
CDMA Cellular Handsets
Wideband CDMA Cellular Handsets
GSM Cellular Handsets
Portable Information Appliances
Device Information(1)
PART NUMBER
LP3981
PACKAGE
BODY SIZE (NOM)
WSON (6)
4.00 mm x 3.00 mm
VSSOP (8)
3.00 mm x 3.00 mm
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
Typical Application Circuit
2(2)
IN
2.2 µF
OUT
1(1)
2.2 µF
LP3981
OUT-SENSE
7(6)
BYPASS
EN
4(3)
6(5)
5(4)
Note: Pin numbers in parenthesis indicate WSON package.
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.
LP3981
SNVS159H – OCTOBER 2001 – REVISED JULY 2015
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Table of Contents
1
2
3
4
5
6
7
8
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
6.7
4
4
4
4
5
6
7
Absolute Maximum Ratings ......................................
ESD Ratings..............................................................
Recommended Operating Conditions.......................
Thermal Information ..................................................
Electrical Characteristics...........................................
Timing Requirements ................................................
Typical Characteristics ..............................................
Parameter Measurement Information .................. 9
Detailed Description ............................................ 10
8.1 Overview ................................................................. 10
8.2 Functional Block Diagram ....................................... 10
8.3 Feature Description................................................. 10
8.4 Device Functional Modes........................................ 11
9
Application and Implementation ........................ 12
9.1 Application Information............................................ 12
9.2 Typical Application ................................................. 12
10 Power Supply Recommendations ..................... 15
11 Layout................................................................... 15
11.1 Layout Guidelines ................................................. 15
11.2 Layout Example .................................................... 15
12 Device and Documentation Support ................. 16
12.1
12.2
12.3
12.4
Community Resources..........................................
Trademarks ...........................................................
Electrostatic Discharge Caution ............................
Glossary ................................................................
16
16
16
16
13 Mechanical, Packaging, and Orderable
Information ........................................................... 16
4 Revision History
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
Changes from Revision G (May 2013) to Revision H
Page
•
Added Device Information and Pin Configuration and Functions sections, ESD Rating table, Feature Description,
Device Functional Modes, Application and Implementation, Power Supply Recommendations, Layout, Device and
Documentation Support , and Mechanical, Packaging, and Orderable Information sections ................................................ 1
•
Update pin names to TI nomenclature .................................................................................................................................. 1
•
Deleted Ordering Information table - duplicative of POA ....................................................................................................... 1
•
Deleted Lead temperature spec from Abs Max table - it is in POA. ..................................................................................... 4
•
Deleted rows for max power dissipation - info in Power Dissipation and Device Operation ................................................. 4
•
Deleted rows for max power dissipation - info in Power Dissipation and Device Operation ................................................. 4
•
Added 2 new paragraphs to Power Dissipation and Device Operation subsection. ............................................................ 13
Changes from Revision F (May 2013) to Revision G
•
2
Page
Changed layout of National Data Sheet to TI format ........................................................................................................... 10
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5 Pin Configuration and Functions
DGK Package
8-Pin VSSOP
Top View
OUT
1
8
NC
IN
2
7
EN
LP3981
NC
3
6
BYPASS
OUT-SENSE
4
5
GND
NGC Package
6-Pin WSON With Exposed Thermal Pad
Top View
OUT 1
6 EN
Device
Code
IN 2
OUT-SENSE 3
5 BYPASS
4 GND
GND
Pin Descriptions
PIN
NAME
TYPE
DESCRIPTION
VSSOP
WSON
BYPASS
6
5
—
EN
7
6
I
Enable input logic, enable high.
GND
5
4
G
Common ground. Connect to PAD.
Input voltage of the LDO.
Optional bypass capacitor for noise reduction.
IN
2
2
I
NC
3, 8
—
—
No internal connection.
OUT
1
1
O
Output voltage of the LDO.
OUT-SENSE
4
3
O
Output. Voltage sense pin. Must be connected to OUT for proper
operation.
THERMAL PAD
—
√
—
Common ground. Connect to pin 4.
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6 Specifications
6.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted) (1) (2) (3)
IN, EN
MIN
MAX
UNIT
−0.3
6.5
V
−0.3 to VIN + 0.3
OUT, OUT-SENSE
Junction temperature
−65
Storage temperature, Tstg
(1)
(2)
(3)
6.5
V
150
°C
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.
All voltages are with respect to the potential at the GND pin.
If Military/Aerospace specified devices are required, contact the TI Sales Office/Distributors for availability and specifications.
6.2 ESD Ratings
VALUE
V(ESD)
(1)
Electrostatic discharge
Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001 (1)
±2000
Machine model
±200
UNIT
V
JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
6.3 Recommended Operating Conditions
over operating free-air temperature range (unless otherwise noted) (1) (2)
MIN
VIN
VEN
Junction temperature
(1)
(2)
NOM
MAX
2.7
6
UNIT
V
0
VIN
V
–40
125
°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.
All voltages are with respect to the potential at the GND pin.
6.4 Thermal Information
LP3981
THERMAL METRIC (1)
DGK (VSSOP)
NGC (WSON)
8 PINS
6 PINS
UNIT
RθJA
Junction-to-ambient thermal resistance, High K
177
56.5
°C/W
RθJC(top)
Junction-to-case (top) thermal resistance
67.7
76.8
°C/W
RθJB
Junction-to-board thermal resistance
97.4
30.9
°C/W
ψJT
Junction-to-top characterization parameter
10.8
3.3
°C/W
ψJB
Junction-to-board characterization parameter
96
31
°C/W
RθJC(bot)
Junction-to-case (bottom) thermal resistance
N/A
10.7
°C/W
(1)
4
For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application
report, SPRA953.
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6.5 Electrical Characteristics
Unless otherwise specified: VEN = 1.2 V, VIN = VOUT + 0.5 V, CIN = 2.2 µF, CBP = 0.033 µF, IOUT = 1 mA, COUT = 2.2 µF. All
values are for TJ = 25°C, unless otherwise specified. (1) (2)
PARAMETER
Output voltage tolerance
ΔVOUT
Line regulation error
TEST CONDITIONS
MIN
TJ = –40°C to +125°C
VIN = VOUT + 0.5 V to 6 V, TA < 85°C
−0.1
VIN = VOUT + 0.5 V to 6 V, TJ ≤125°C
–0.2
PSRR
Power supply rejection ratio (4)
Quiescent current
0.005
IOUT = 1 mA to 300 mA
TJ = –40°C to +125°C
0.005
VIN = VOUT(nom) + 1 V,
ƒ = 1 kHz,
IOUT = 50 mA (Figure 16)
50
VIN = VOUT(nom) + 1 V,
ƒ = 10 kHz,
IOUT = 50 mA (Figure 16)
55
VEN = 1.2 V, IOUT = 1 mA
70
VEN = 1.2 V, IOUT = 1 mA to 300 mA,
VOUT = 2.5 V (5)
0.003
1.5
0.5
5
IOUT = 200 mA
88
IOUT = 200 mA, TJ = –40°C to +125°C
132
IOUT = 300 mA, TJ = –40°C to +125°C
en
Output noise voltage
Thermal shutdown hysteresis
Peak output current
VOUT ≥ VOUT (nom) – 5%
Maximum input current at VEN
VEN = 0 and VIN
VIL
Logic low input threshold
VIN = 2.7 V to 6 V, TJ = –40°C to +125°C
VIH
Logic high input threshold
VIN = 2.7 V to 6 V, TJ = –40°C to +125°C
(6)
mA
35
µVRMS
°C
20
IEN
(2)
(3)
(4)
(5)
600
160
IOUT(PK)
(1)
200
Thermal shutdown temperature
TSD
mV
133
IOUT = 300 mA
BW = 10 Hz to 100 kHz,
CBP = 0.033 µF
µA
210
IOUT = 1 mA, TJ = –40°C to +125°C
Output grounded (steady state)
dB
170
VEN = 1.2 V, IOUT = 1 mA to 300 mA,
VOUT = 2.5 V
TJ = –40°C to +125°C (5)
Short-circuit current limit
%/mA
120
IOUT = 1 mA
ISC
%/V
0.2
VEN = 0.4 V, TJ = –40°C to +125°C
(6)
0.1
0.0003
VEN = 0.4 V
Dropout voltage
UNIT
% of
3 VOUT(nom)
VEN = 1.2 V, IOUT = 1 mA
TJ = –40°C to +125°C
IQ
MAX
2
–3
IOUT = 1 mA to 300 mA
Load regulation error (3)
TYP
−2
300
455
mA
0.001
µA
0.4
1.4
Minimum (MIN) and maximum (MAX) limits are ensured by design, test, or statistical analysis. Typical (TYP) numbers are not verified,
but do represent the most likely norm.
The target output voltage, which is labeled VOUT(nom), is the desired voltage option.
An increase in the load current results in a slight decrease in the output voltage and vice versa.
Specified by design. Not production tested.
For VOUT > 2.5 V, increase IQ(MAX) by 2.5 µA for every 0.1 V increase in VOUT(nom); that is,
IQ(MAX) = 210 µA + ((VOUT(NOM) – 2.5) × 25) µA .
Dropout voltage is the input-to-output voltage difference at which the output voltage is 100 mV below its nominal value. This
specification does not apply for input voltages below 2.5 V.
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Electrical Characteristics (continued)
Unless otherwise specified: VEN = 1.2 V, VIN = VOUT + 0.5 V, CIN = 2.2 µF, CBP = 0.033 µF, IOUT = 1 mA, COUT = 2.2 µF. All
values are for TJ = 25°C, unless otherwise specified.(1)(2)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
OUTPUT CAPACITANCE
COUT
Output capacitor
Capacitance
ESR
2.2
22
µF
5
500
mΩ
6.6 Timing Requirements
MIN
tON
Turnon time (1) (2)
CBYPASS = 0.033 µF
6
MAX
240
CBYPASS = 0.033 µF, TJ = –40°C to +125°C
(1)
(2)
NOM
UNIT
µs
350
Specified by design. Not production tested.
Turnon time is time measured between the enable input just exceeding VIH and the output voltage just reaching 95% of its nominal
value.
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6.7 Typical Characteristics
Unless otherwise specified, CIN = COUT = 2.2 µF ceramic, CBP = 0.033 µF, VIN = VOUT + 0.5 V, TA = 25°C, EN pin is tied to VIN.
VOUT = 2.83 V
VOUT = 2.85 V
Figure 1. Output Voltage vs. Temperature
Figure 2. Dropout Voltage vs. Temperature
VOUT = 2.85 V
Figure 4. Output Short Circuit Current
Figure 3. Ground Current vs. Load Current
VIN = VOUT + 1 V
Figure 5. Output Short Circuit Current
Figure 6. Ripple Rejection
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Typical Characteristics (continued)
Unless otherwise specified, CIN = COUT = 2.2 µF ceramic, CBP = 0.033 µF, VIN = VOUT + 0.5 V, TA = 25°C, EN pin is tied to VIN.
VIN = VOUT + 1 V
VIN = VOUT + 1 V
Figure 7. Ripple Rejection
Figure 8. Ripple Rejection
VIN = 3.5 V
VIN = 3.5 V
Figure 9. Load Transient Response
8
Figure 10. Load Transient Response
VIN = VOUT + 1 V To VOUT + 1.6 V
VIN = VOUT + 1 V to VOUT + 1.6 V
Figure 11. Line Transient Response
Figure 12. Line Transient Response
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Typical Characteristics (continued)
Unless otherwise specified, CIN = COUT = 2.2 µF ceramic, CBP = 0.033 µF, VIN = VOUT + 0.5 V, TA = 25°C, EN pin is tied to VIN.
Figure 13. Enable Response (tON)
Figure 14. Enable Response (tON)
7 Parameter Measurement Information
Figure 15. Line Transient Response Input Perturbation
Figure 16. PSRR Input Perturbation
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8 Detailed Description
8.1 Overview
The LP3981 family of fixed-output, ultra-low-dropout, and low-noise regulators offers exceptional performance for
battery-powered applications. Available for voltages from 2.5-V to 3.3-V, the family is capable of delivering
300-mA continuous load current.
The LP3981 contains several features to facilitate battery-powered designs:
• Low dropout voltage , typical dropout of 132-mV at 300-mA load current.
• Low quiescent current and low ground current. Ground current is typically 170 µA at 150-mA load, and 70 µA
at 1-mA load.
• A shutdown feature is available , allowing the regulator to consume only 0.003 µA typically when the EN pin
is pulled low.
• Power supply rejection is 60-dB at 1 kHZ.
• Low noise; BYPASS pin allows for low-noise operation, with typically 35-µVRMS output noise over 10 Hz to
100 kHz.
8.2 Functional Block Diagram
IN
HIGH = ON
EN
OUT
VREFERENCE
1.23 V
Fast Turnon
Circuit
LOW = OFF
OUT-SENSE
BYPASS
R2
Overcurrent and
Thermal Protection
GND
8.3 Feature Description
8.3.1 On/Off Input Operation
The LP3981 is turned off by pulling the EN pin low, and turned on by pulling it high. If this feature is not used, the
EN pin must be tied to VIN to keep the regulator output on at all time. To assure proper operation, the signal
source used to drive the EN input must be able to swing above and below the specified turnon and turnoff
voltage thresholds listed in Electrical Characteristics under VIL and VIH.
8.3.2 Fast On-Time
The LP3981 utilizes a speed up circuitry to ramp up the internal VREF voltage to its final value to achieve a fast
output turn on time.
10
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8.4 Device Functional Modes
8.4.1 Operation with VOUT(TARGET) + 0.3 V ≤ VIN ≤ 6 V
The device operate if the input voltage is equal to, or exceeds VOUT(TARGET) + 0.3 V. At input voltages below the
minimum VIN requirement, the devices do not operate correctly and output voltage may not reach target value.
8.4.2 Operation With EN Control
If the voltage on the EN pin is less than 0.4 V, the device is disabled, and in this state the shutdown current does
not exceed 1.5 μA. Raising EN above 1.4 V initiates the start-up sequence of the device.
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9 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 must
validate and test their design implementation to confirm system functionality.
9.1 Application Information
The LP3981 can provide 300-mA output current with 2.5-V to 6-V input. It is stable with a 2.2-μF ceramic output
capacitor. An optional external bypass capacitor reduces the output noise without slowing down the load
transient response. Typical output noise is 35 µVRMS at frequencies from 10 Hz to 100 kHz. Typical power supply
rejection is 60 dB at 1 kHz.
9.2 Typical Application
2(2)
IN
2.2 µF
OUT
1(1)
2.2 µF
LP3981
OUT-SENSE
7(6)
BYPASS
EN
4(3)
6(5)
5(4)
Figure 17. LP3981 Typical Application
9.2.1 Design Requirements
Example requirements for typical voltage inverter applications:
Table 1. Design Parameters
DESIGN PARAMETER
EXAMPLE VALUE
Input voltage
3.5 V, ±10%
Output voltage
2.5 V, ±5%
Output current
300 mA (maximum)
RMS noise, 10 Hz to100 kHz
35 μVRMS
PSRR at 1 kHz
60 dB
9.2.2 Detailed Design Procedure
9.2.2.1 Power Dissipation and Device Operation
The permissible power dissipation for any package is a measure of the capability of the device to pass heat from
the power source, the junctions of the device, to the ultimate heat sink, the ambient environment. Thus, the
power dissipation is dependant on the ambient temperature and the thermal resistance across the various
interfaces between the die and ambient air.
As stated in the notes for Absolute Maximum Ratings and Recommended Operating Conditions, the allowable
power dissipation for the device in a given package can be calculated using Equation 1:
2& =
12
6, (/#: ) F 6# )
4à,#
(1)
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With an RθJA = 56.5°C/W, the device in the WSON package returns a value of 1.77 W with a maximum junction
temperature of 125°C and an ambient temperature of 25°C. The device in a VSSOP package returns a figure of
0.565 W (R θJA = 177°C/W).
The actual power dissipation across the device can be represented by Equation 2:
2& = :8+0 F 8176 ; × +176
(2)
This establishes the relationship between the power dissipation allowed due to thermal considerations, the
voltage drop across the device, and the continuous current capability of the device. The device can deliver 300
mA but care must be taken when choosing the continuous current output for the device under the operating load
conditions.
The RθJA value is not a characteristic of the package by itself but of the package, the printed circuit board
(PCB), and other environmental factors. Equation 2 is only valid when the application configuration matches the
EIA/JEDEC JESD51-7 (High-K) configuration in which RθJA was either measured or modeled. Few, if any, user
applications conform to the PCB configuration defined by the EIA/JEDEC standards. As a result, the RθJA values
are useful only when comparing assorted packages that have been measured or modeled to the EIA/JEDEC
standards, but are of little use to estimate real world junction temperatures.
The EIA/JEDEC standard JESD51-2 provides methodologies to estimate the junction temperature from external
measurements (ψJB references the temperature at the PCB, and ψJT references the temperature at the top
surface of the package) when operating under steady-state power dissipation conditions. These methodologies
have been determined to be relatively independent of the PCB attached to the package when compared to the
more typical RθJA. Refer to Semiconductor and IC Package Thermal Metrics application report, SPRA953, for
specifics.
9.2.2.2 External Capacitors
Like any low-dropout regulator, the LP3981 requires external capacitors for regulator stability. The LP3981 is
specifically designed for portable applications requiring minimum board space and smallest components. These
capacitors must be correctly selected for good performance.
9.2.2.3 Input Capacitor
An input capacitance of ≊ 2.2 µF is required between the LP3981 input pin and ground (the amount of the
capacitance may be increased without limit).
This capacitor must be located a distance of not more than 1 cm from the input pin and returned to a clean
analog ground. Any good quality ceramic, tantalum, or film capacitor may be used at the input.
NOTE
Tantalum capacitors can suffer catastrophic failures due to surge current when connected
to a low-impedance source of power (like a battery or a very large capacitor). If a tantalum
capacitor is used at the input, it must be specified by the manufacturer to have a surge
current rating sufficient for the application.
There are no requirements for the ESR on the input capacitor, but tolerance and temperature coefficient must be
considered when selecting the capacitor to ensure the capacitance is ≊ 2.2 µF over the entire operating
temperature range.
9.2.2.4 Output Capacitor
The LP3981 is designed specifically to work with very small ceramic output capacitors. A ceramic capacitor
(dielectric types Z5U, Y5V or X7R) in the 2.2-µF to 22-µF range with 5-mΩ to 500-mΩ ESR is suitable in the
LP3981 application circuit.
It is also possible to use tantalum or film capacitors at the output, but these are not as attractive for reasons of
size and cost (see Capacitor Characteristics).
The output capacitor must meet the requirement for minimum amount of capacitance and also have an
equivalent series resistance (ESR) value which is within a stable range (5 mΩ to 500 mΩ).
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9.2.2.5 No-Load Stability
The LP3981 remains stable and in regulation with no external load. This is specially important in CMOS RAM
keep-alive applications.
9.2.2.6 Noise Bypass Capacitor
Connecting a 0.033-µF capacitor between the BYPASS pin and ground significantly reduces noise on the
regulator output. This capacitor is connected directly to a high impedance node in the bad gap reference circuit.
Any significant loading on this node causes a change on the regulated output voltage. For this reason, DC
leakage current through this pin must 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. Hight-quality ceramic
capacitors with either NPO or COG dielectric typically have very low leakage. Polypropolene and polycarbonate
film capacitors are available in small surface-mount packages and typically have extremely low leakage current.
Unlike many other LDOs, addition of a noise reduction capacitor does not effect the transient response of the
device.
9.2.2.7 Capacitor Characteristics
The LP3981 is designed to work with ceramic capacitors on the output to take advantage of the benefits they
offer: for capacitance values in the range of 1 µF to 4.7 µF, ceramic capacitors are the smallest, least expensive
and have the lowest ESR values (which makes them best for eliminating high frequency noise). The ESR of a
typical 1µF ceramic capacitor is in the range of 20 mΩ to 40 mΩ, which easily meets the ESR requirement for
stability by the LP3981.
Capacitance of a ceramic capacitor can vary with temperature. Most large value ceramic capacitors (≊ 2.2 µF)
are manufactured with Z5U or Y5V temperature characteristics, which results in the capacitance dropping by
more than 50% as the temperature goes from 25°C to 85°C.
A better choice for temperature coefficient in a ceramic capacitor is X7R, which holds the capacitance within
±15%.
Tantalum capacitors are less desirable than ceramic for use as output capacitors because they are 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 equivalently sized
ceramics. This means that 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 must also be noted that the ESR of a typical tantalum increases about 2:1
as the temperature goes from 25°C down to −40°C, so some guard band must be allowed.
9.2.3 Application Curves
14
VIN = VOUT + 1 V to VOUT + 1.6 V
VIN = VOUT + 1V to VOUT + 1.6 V
Figure 18. Line Transient Response
Figure 19. Line Transient Response
Submit Documentation Feedback
Copyright © 2001–2015, Texas Instruments Incorporated
Product Folder Links: LP3981
LP3981
www.ti.com
SNVS159H – OCTOBER 2001 – REVISED JULY 2015
10 Power Supply Recommendations
The LP3981 is designed to operate from an input voltage supply range between 2.5 V and 6 V. The input voltage
range provides adequate headroom in order 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 to improve the
output noise performance.
11 Layout
11.1 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.
11.2 Layout Example
COUT
OUT
1
6
EN
IN
2
5
BYPASS
OUT-SENSE
3
4
CBYPASS
CIN
GND
Figure 20. LP3981 Layout Example
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Copyright © 2001–2015, Texas Instruments Incorporated
Product Folder Links: LP3981
15
LP3981
SNVS159H – OCTOBER 2001 – REVISED JULY 2015
www.ti.com
12 Device and Documentation Support
12.1 Community Resources
The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective
contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of
Use.
TI E2E™ Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration
among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help
solve problems with fellow engineers.
Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and
contact information for technical support.
12.2 Trademarks
E2E is a trademark of Texas Instruments.
All other trademarks are the property of their respective owners.
12.3 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.
12.4 Glossary
SLYZ022 — TI Glossary.
This glossary lists and explains terms, acronyms, and definitions.
13 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.
16
Submit Documentation Feedback
Copyright © 2001–2015, Texas Instruments Incorporated
Product Folder Links: LP3981
PACKAGE OPTION ADDENDUM
www.ti.com
8-Oct-2015
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
Lead/Ball Finish
MSL Peak Temp
(2)
(6)
(3)
Op Temp (°C)
Device Marking
(4/5)
LP3981ILD-2.5/NOPB
ACTIVE
WSON
NGC
6
1000
Green (RoHS
& no Sb/Br)
CU SN
Level-3-260C-168 HR
-40 to 125
LO1UB
LP3981ILD-3.0/NOPB
ACTIVE
WSON
NGC
6
1000
Green (RoHS
& no Sb/Br)
CU NIPDAU | CU SN
Level-3-260C-168 HR
LP3981ILD-3.3/NOPB
ACTIVE
WSON
NGC
6
1000
Green (RoHS
& no Sb/Br)
CU NIPDAU | CU SN
Level-3-260C-168 HR
-40 to 125
LO1XB
LP3981ILDX-2.5/NOPB
ACTIVE
WSON
NGC
6
4500
Green (RoHS
& no Sb/Br)
CU SN
Level-3-260C-168 HR
-40 to 125
LO1UB
LP3981ILDX-2.7/NOPB
ACTIVE
WSON
NGC
6
4500
Green (RoHS
& no Sb/Br)
CU NIPDAU | CU SN
Level-3-260C-168 HR
-40 to 125
LO1VB
LP3981ILDX-2.8/NOPB
ACTIVE
WSON
NGC
6
4500
Green (RoHS
& no Sb/Br)
CU SN
Level-3-260C-168 HR
-40 to 125
L01ZB
LP3981ILDX-2.83/NOPB
ACTIVE
WSON
NGC
6
4500
Green (RoHS
& no Sb/Br)
CU NIPDAU | CU SN
Level-3-260C-168 HR
-40 to 125
LO1SB
LP3981ILDX-3.03/NOPB
ACTIVE
WSON
NGC
6
4500
Green (RoHS
& no Sb/Br)
CU SN
Level-3-260C-168 HR
-40 to 125
LO1YB
L017B
LP3981IMM-2.5
NRND
VSSOP
DGK
8
1000
TBD
Call TI
Call TI
-40 to 125
LFKB
LP3981IMM-2.5/NOPB
ACTIVE
VSSOP
DGK
8
1000
Green (RoHS
& no Sb/Br)
CU SN
Level-1-260C-UNLIM
-40 to 125
LFKB
LP3981IMM-2.7/NOPB
ACTIVE
VSSOP
DGK
8
1000
Green (RoHS
& no Sb/Br)
CU SN
Level-1-260C-UNLIM
-40 to 125
LFLB
LP3981IMM-2.8/NOPB
ACTIVE
VSSOP
DGK
8
1000
Green (RoHS
& no Sb/Br)
CU SN
Level-1-260C-UNLIM
-40 to 125
LFTB
LP3981IMM-3.0/NOPB
ACTIVE
VSSOP
DGK
8
1000
Green (RoHS
& no Sb/Br)
CU SN
Level-1-260C-UNLIM
LF3B
LP3981IMM-3.03
NRND
VSSOP
DGK
8
1000
TBD
Call TI
Call TI
-40 to 125
LFPB
LP3981IMM-3.03/NOPB
ACTIVE
VSSOP
DGK
8
1000
Green (RoHS
& no Sb/Br)
CU SN
Level-1-260C-UNLIM
-40 to 125
LFPB
LP3981IMM-3.3
NRND
VSSOP
DGK
8
1000
TBD
Call TI
Call TI
-40 to 125
LFNB
LP3981IMM-3.3/NOPB
ACTIVE
VSSOP
DGK
8
1000
Green (RoHS
& no Sb/Br)
CU SN
Level-1-260C-UNLIM
-40 to 125
LFNB
LP3981IMMX-2.5/NOPB
ACTIVE
VSSOP
DGK
8
3500
Green (RoHS
& no Sb/Br)
CU SN
Level-1-260C-UNLIM
-40 to 125
LFKB
Addendum-Page 1
Samples
PACKAGE OPTION ADDENDUM
www.ti.com
Orderable Device
8-Oct-2015
Status
(1)
LP3981IMMX-3.3/NOPB
ACTIVE
Package Type Package Pins Package
Drawing
Qty
VSSOP
DGK
8
3500
Eco Plan
Lead/Ball Finish
MSL Peak Temp
(2)
(6)
(3)
Green (RoHS
& no Sb/Br)
CU SN
Level-1-260C-UNLIM
Op Temp (°C)
Device Marking
(4/5)
-40 to 125
LFNB
(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.
(4)
There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device.
(5)
Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation
of the previous line and the two combined represent the entire Device Marking for that device.
(6)
Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish
value exceeds the maximum column width.
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
Samples
PACKAGE MATERIALS INFORMATION
www.ti.com
24-Feb-2016
TAPE AND REEL INFORMATION
*All dimensions are nominal
Device
Package Package Pins
Type Drawing
SPQ
Reel
Reel
A0
Diameter Width (mm)
(mm) W1 (mm)
B0
(mm)
K0
(mm)
P1
(mm)
W
Pin1
(mm) Quadrant
LP3981ILD-2.5/NOPB
WSON
NGC
6
1000
178.0
12.4
4.3
3.3
1.0
8.0
12.0
Q1
LP3981ILD-3.0/NOPB
WSON
NGC
6
1000
180.0
12.4
4.3
3.3
1.0
8.0
12.0
Q1
LP3981ILD-3.3/NOPB
WSON
NGC
6
1000
180.0
12.4
4.3
3.3
1.0
8.0
12.0
Q1
LP3981ILDX-2.5/NOPB
WSON
NGC
6
4500
330.0
12.4
4.3
3.3
1.0
8.0
12.0
Q1
LP3981ILDX-2.7/NOPB
WSON
NGC
6
4500
330.0
12.4
4.3
3.3
1.0
8.0
12.0
Q1
LP3981ILDX-2.8/NOPB
WSON
NGC
6
4500
330.0
12.4
4.3
3.3
1.0
8.0
12.0
Q1
LP3981ILDX-2.83/NOPB
WSON
NGC
6
4500
330.0
12.4
4.3
3.3
1.0
8.0
12.0
Q1
LP3981ILDX-3.03/NOPB
WSON
NGC
6
4500
330.0
12.4
4.3
3.3
1.0
8.0
12.0
Q1
LP3981IMM-2.5
VSSOP
DGK
8
1000
178.0
12.4
5.3
3.4
1.4
8.0
12.0
Q1
LP3981IMM-2.5/NOPB
VSSOP
DGK
8
1000
178.0
12.4
5.3
3.4
1.4
8.0
12.0
Q1
LP3981IMM-2.7/NOPB
VSSOP
DGK
8
1000
178.0
12.4
5.3
3.4
1.4
8.0
12.0
Q1
LP3981IMM-2.8/NOPB
VSSOP
DGK
8
1000
178.0
12.4
5.3
3.4
1.4
8.0
12.0
Q1
LP3981IMM-3.0/NOPB
VSSOP
DGK
8
1000
178.0
12.4
5.3
3.4
1.4
8.0
12.0
Q1
LP3981IMM-3.03
VSSOP
DGK
8
1000
178.0
12.4
5.3
3.4
1.4
8.0
12.0
Q1
LP3981IMM-3.03/NOPB
VSSOP
DGK
8
1000
178.0
12.4
5.3
3.4
1.4
8.0
12.0
Q1
LP3981IMM-3.3
VSSOP
DGK
8
1000
178.0
12.4
5.3
3.4
1.4
8.0
12.0
Q1
LP3981IMM-3.3/NOPB
VSSOP
DGK
8
1000
178.0
12.4
5.3
3.4
1.4
8.0
12.0
Q1
LP3981IMMX-2.5/NOPB
VSSOP
DGK
8
3500
330.0
12.4
5.3
3.4
1.4
8.0
12.0
Q1
Pack Materials-Page 1
PACKAGE MATERIALS INFORMATION
www.ti.com
24-Feb-2016
Device
LP3981IMMX-3.3/NOPB
Package Package Pins
Type Drawing
VSSOP
DGK
8
SPQ
Reel
Reel
A0
Diameter Width (mm)
(mm) W1 (mm)
3500
330.0
12.4
5.3
B0
(mm)
K0
(mm)
P1
(mm)
3.4
1.4
8.0
W
Pin1
(mm) Quadrant
12.0
Q1
*All dimensions are nominal
Device
Package Type
Package Drawing
Pins
SPQ
Length (mm)
Width (mm)
Height (mm)
LP3981ILD-2.5/NOPB
WSON
NGC
6
1000
213.0
191.0
55.0
LP3981ILD-3.0/NOPB
WSON
NGC
6
1000
195.0
200.0
45.0
LP3981ILD-3.3/NOPB
WSON
NGC
6
1000
195.0
200.0
45.0
LP3981ILDX-2.5/NOPB
WSON
NGC
6
4500
367.0
367.0
35.0
LP3981ILDX-2.7/NOPB
WSON
NGC
6
4500
370.0
355.0
55.0
LP3981ILDX-2.8/NOPB
WSON
NGC
6
4500
367.0
367.0
35.0
LP3981ILDX-2.83/NOPB
WSON
NGC
6
4500
370.0
355.0
55.0
LP3981ILDX-3.03/NOPB
WSON
NGC
6
4500
367.0
367.0
35.0
LP3981IMM-2.5
VSSOP
DGK
8
1000
210.0
185.0
35.0
LP3981IMM-2.5/NOPB
VSSOP
DGK
8
1000
210.0
185.0
35.0
LP3981IMM-2.7/NOPB
VSSOP
DGK
8
1000
210.0
185.0
35.0
LP3981IMM-2.8/NOPB
VSSOP
DGK
8
1000
210.0
185.0
35.0
LP3981IMM-3.0/NOPB
VSSOP
DGK
8
1000
210.0
185.0
35.0
LP3981IMM-3.03
VSSOP
DGK
8
1000
210.0
185.0
35.0
LP3981IMM-3.03/NOPB
VSSOP
DGK
8
1000
210.0
185.0
35.0
LP3981IMM-3.3
VSSOP
DGK
8
1000
210.0
185.0
35.0
Pack Materials-Page 2
PACKAGE MATERIALS INFORMATION
www.ti.com
24-Feb-2016
Device
Package Type
Package Drawing
Pins
SPQ
Length (mm)
Width (mm)
Height (mm)
LP3981IMM-3.3/NOPB
VSSOP
DGK
8
1000
210.0
185.0
35.0
LP3981IMMX-2.5/NOPB
VSSOP
DGK
8
3500
367.0
367.0
35.0
LP3981IMMX-3.3/NOPB
VSSOP
DGK
8
3500
367.0
367.0
35.0
Pack Materials-Page 3
MECHANICAL DATA
NGC0006D
LDC06D (Rev B)
www.ti.com
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