ETC LP2986

LP2986
Micropower, 200 mA Ultra Low-Dropout Fixed or
Adjustable Voltage Regulator
General Description
Features
The LP2986 is a 200 mA precision LDO voltage regulator
which offers the designer a higher performance version of
the industry standard LP2951.
Using an optimized VIP™ (Vertically Integrated PNP) process, the LP2986 delivers superior performance:
Dropout Voltage: Typically 180 mV @ 200 mA load, and 1
mV @ 1 mA load.
Ground Pin Current: Typically 1 mA @ 200 mA load, and
200 µA @ 10 mA load.
Sleep Mode: The LP2986 draws less than 1 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: The standard product versions available
can be pin-strapped (using the internal resistive divider) to
provide output voltages of 5.0V, 3.3V, or 3.0V with guaranteed accuracy of 0.5% (“A” grade) and 1% (standard grade)
at room temperature.
n
n
n
n
n
n
n
n
n
n
Ultra low dropout voltage
Guaranteed 200 mA output current
SO-8 and mini-SO8 surface mount packages
< 1 µA quiescent current when shutdown
Low ground pin current at all loads
0.5% output voltage accuracy (“A” grade)
High peak current capability (400 mA typical)
Wide supply voltage range (16V max)
Overtemperature/overcurrent protection
−40˚C to +125˚C junction temperature range
Applications
n Cellular Phone
n Palmtop/Laptop Computer
n Camcorder, Personal Stereo, Camera
Block Diagram
01293501
VIP™ is a trademark of National Semiconductor Corporation.
© 2002 National Semiconductor Corporation
DS012935
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LP2986 Micropower, 200 mA Ultra Low-Dropout Fixed or Adjustable Voltage Regulator
January 2002
LP2986
Connection Diagrams and Ordering Information
Surface Mount Packages:
8-Lead LLP Surface Mount Package
01293502
SO-8/Mini SO-8 Package
See NS Package Drawing Number M08A/MUA08A
01293543
Top View
See NS Package Drawing Number LDC08A
Basic Application Circuits
Application Using Internal Resistive Divider
01293503
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2
LP2986
Basic Application Circuits
(Continued)
Application Using External Divider
01293504
Ordering Information
TABLE 1. Package Marking and Ordering Information
Output Voltage
Grade
Order Information
Package Marking
Supplied as:
5
A
LP2986AIMMX-5.0
L41A
3500 Units on Tape and
Reel
5
A
LP2986AIMM-5.0
L41A
1000 Units on Tape and
Reel
5
STD
LP2986IMMX-5.0
L41B
3500 Units on Tape and
Reel
5
STD
LP2986IMM-5.0
L41B
1000 Units on Tape and
Reel
3.3
A
LP2986AIMMX-3.3
L40A
3500 Units on Tape and
Reel
3.3
A
LP2986AIMM-3.3
L40A
1000 Units on Tape and
Reel
3.3
STD
LP2986IMMX-3.3
L40B
3500 Units on Tape and
Reel
3.3
STD
LP2986IMM-3.3
L40B
1000 Units on Tape and
Reel
3.0
A
LP2986AIMMX-3.0
L39A
3500 Units on Tape and
Reel
3.0
A
LP2986AIMM-3.0
L39A
1000 Units on Tape and
Reel
3.0
STD
LP2986IMMX-3.0
L39B
3500 Units on Tape and
Reel
3.0
STD
LP2986IMM-3.0
L39B
1000 Units on Tape and
Reel
Mini SO-8
3
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LP2986
Ordering Information
(Continued)
TABLE 1. Package Marking and Ordering Information (Continued)
Output Voltage
Grade
Order Information
Package Marking
Supplied as:
5
A
LP2986AIMX-5.0
2986AIM5.0
2500 Units on Tape and
Reel
5
A
LP2986AIM-5.0
2986AIM5.0
Shipped in Anti-Static
Rails
5
STD
LP2986IMX-5.0
2986IM5.0
2500 Units on Tape and
Reel
5
STD
LP2986IM-5.0
2986IM5.0
Shipped in Anti-Static
Rails
3.3
A
LP2986AIMX-3.3
2986AIM3.3
2500 Units on Tape and
Reel
3.3
A
LP2986AIM-3.3
2986AIM3.3
Shipped in Anti-Static
Rails
3.3
STD
LP2986IMX-3.3
2986IM3.3
2500 Units on Tape and
Reel
3.3
STD
LP2986IM-3.3
2986IM3.3
Shipped in Anti-Static
Rails
3.0
A
LP2986AIMX-3.0
2986AIM3.0
2500 Units on Tape and
Reel
3.0
A
LP2986AIM-3.0
2986AIM3.0
Shipped in Anti-Static
Rails
3.0
STD
LP2986IMX-3.0
2986IM3.0
2500 Units on Tape and
Reel
3.0
STD
LP2986IM-3.0
2986IM3.0
Shipped in Anti-Static
Rails
5
A
LP2986AILD-5
L006A
1000 Units on Tape and
Reel
5
A
LP2986AILDX-5
L006A
4500 Units on Tape and
Reel
5
STD
LP2986ILD-5
L006AB
1000 Units on Tape and
Reel
5
STD
LP2986ILDX-5
L006AB
4500 Units on Tape and
Reel
3.3
A
LP2986AILD-3.3
L005A
1000 Units on Tape and
Reel
3.3
A
LP2986AILDX-3.3
L005A
4500 Units on Tape and
Reel
3.3
STD
LP2986ILD-3.3
L005AB
1000 Units on Tape and
Reel
3.3
STD
LP2986ILDX-3.3
L005AB
4500 Units on Tape and
Reel
3.0
A
LP2986AILD-3.0
L004A
1000 Units on Tape and
Reel
3.0
A
LP2986AILDX-3.0
L004A
4500 Units on Tape and
Reel
3.0
STD
LP2986ILD-3.0
L004AB
1000 Units on Tape and
Reel
3.0
STD
LP2986ILDX-3.0
L004AB
4500 Units on Tape and
Reel
SO-8
8-Lead LLP
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4
Input Supply Voltage
(Operating)
(Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Shutdown Pin
−0.3V to +16V
Feedback Pin
−0.3V to +5V
Storage Temperature Range
−65˚C to +150˚C
Operating Junction
Temperature Range
Output Voltage
(Survival) (Note 4)
−40˚C to +125˚C
IOUT (Survival)
Lead Temperature
(Soldering, 5 seconds)
−0.3V to +16V
Short Circuit Protected
Input-Output Voltage
(Survival) (Note 5)
260˚C
ESD Rating (Note 2)
2.1V to +16V
−0.3V to +16V
2 kV
Power Dissipation (Note 3)
Internally Limited
Input Supply Voltage
(Survival)
−0.3V to +16V
Electrical Characteristics
Limits in standard typeface are for T J = 25˚C, and limits in boldface type apply over the full operating temperature range. Unless otherwise specified: VIN = VO(NOM) + 1V, IL = 1 mA, COUT = 4.7 µF, CIN = 2.2 µF, VS/D = 2V.
Symbol
VO
Parameter
Output Voltage
(5.0V Versions)
Output Voltage
(3.3V Versions)
Output Voltage
(3.0V Versions)
VIN–VO
Conditions
Typical
5.0
0.1 mA < IL < 200 mA
3.3
0.1 mA < IL < 200 mA
0.1 mA < IL < 200 mA
Output Voltage Line
Regulation
VO(NOM) + 1V ≤ VIN ≤
16V
Dropout Voltage
(Note 7)
IL = 100 µA
3.0
LM2986I-X.X
(Note 6)
Min
Max
Min
Max
4.975
5.025
4.950
5.050
4.960
5.040
4.920
5.080
4.910
5.090
4.860
5.140
3.283
3.317
3.267
3.333
3.274
3.326
3.247
3.353
3.241
3.359
3.208
3.392
2.985
3.015
2.970
3.030
2.976
3.024
2.952
3.048
3.054
2.916
2.946
0.007
1
90
IL = 200 mA
Ground Pin Current
3.3
3.0
IL = 75 mA
IGND
5.0
LM2986AI-X.X
(Note 6)
180
IL = 100 µA
100
IL = 75 mA
500
IL = 200 mA
1
Units
V
3.084
0.014
0.014
0.032
0.032
2.0
2.0
3.5
3.5
120
120
170
170
230
230
350
350
120
120
150
150
800
800
1400
1400
2.1
2.1
3.7
3.7
%/V
mV
µA
mA
VS/D < 0.3V
0.05
IO(PK)
Peak Output Current
VOUT ≥ VO(NOM) − 5%
400
IO(MAX)
Short Circuit Current
RL = 0 (Steady State)
(Note 11)
400
en
Output Noise Voltage
(RMS)
BW = 300 Hz to 50 kHz,
COUT = 10 µF
160
µV(RMS)
Ripple Rejection
f = 1 kHz, COUT = 10 µF
65
dB
5
1.5
250
1.5
µA
250
mA
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LP2986
Absolute Maximum Ratings
LP2986
Electrical Characteristics
(Continued)
Limits in standard typeface are for T J = 25˚C, and limits in boldface type apply over the full operating temperature range. Unless otherwise specified: VIN = VO(NOM) + 1V, IL = 1 mA, COUT = 4.7 µF, CIN = 2.2 µF, VS/D = 2V.
Symbol
Parameter
Output Voltage
Temperature Coefficient
Conditions
Typical
LM2986AI-X.X
(Note 6)
LM2986I-X.X
(Note 6)
Min
Min
Max
Units
Max
(Note 9)
20
ppm/˚C
FEEDBACK PIN
VFB
Feedback Pin Voltage
1.23
(Note 10)
IFB
FB Pin Voltage
Temperature Coefficient
(Note 9)
Feedback Pin Bias
Current
IL = 200 mA
FB Pin Bias Current
Temperature Coefficient
(Note 9)
1.23
1.21
1.25
1.20
1.26
1.20
1.26
1.19
1.27
1.19
1.28
1.18
1.29
20
V
ppm/˚C
150
330
330
760
760
0.1
nA
nA/˚C
SHUTDOWN INPUT
VS/D
IS/D
S/D Input Voltage
(Note 8)
VH = O/P ON
1.4
VL = O/P OFF
0.55
1.6
0.18
1.6
0.18
S/D Input Current
VS/D = 0
0
−1
−1
VS/D = 5V
5
15
15
1
1
2
2
220
220
350
350
V
µA
ERROR COMPARATOR
IOH
VOL
Output “HIGH” Leakage
Output “LOW” Voltage
VTHR
(MAX)
Upper Threshold Voltage
VTHR
(MIN)
Lower Threshold Voltage
HYST
Hysteresis
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VOH = 16V
0.01
VIN = VO(NOM) − 0.5V,
IO(COMP) = 300 µA
150
−4.6
−6.6
2.0
6
−5.5
−3.5
−5.5
−7.7
−2.5
−7.7
−2.5
−8.9
−4.9
−8.9
−4.9
−13.0
−3.3
−13.0
−3.3
µA
mV
−3.5
%VOUT
(Continued)
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the component may occur. Electrical specifications do not apply when operating the
device outside of its rated operating conditions.
Note 2: The ESD rating of the Feedback pin is 500V and the Tap pin is 1.5 kV.
Note 3: The maximum allowable power dissipation is a function of the maximum junction temperature, TJ(MAX), the junction-to-ambient thermal resistance, θJ−A,
and the ambient temperature, TA. The maximum allowable power dissipation at any ambient temperature is calculated using:
The value of θJ−A for the SO-8 (M) package is 160˚C/W, and the mini SO-8 (MM) package is 200˚C/W. The value θJ−A for the LLP (LD) 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 LLP
package, refer to Application Note AN-1187. Exceeding the maximum allowable power dissipation will cause excessive die temperature, and the regulator will go into
thermal shutdown.
Note 4: If used in a dual-supply system where the regulator load is returned to a negative supply, the LM2986 output must be diode-clamped to ground.
Note 5: The output PNP structure contains a diode between the V IN and VOUT terminals 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 (see Application Hints).
Note 6: Limits are 100% production tested at 25˚C. Limits over the operating temperature range are guaranteed through correlation using Statistical Quality Control
(SQC) methods. The limits are used to calculate National’s Average Outgoing Quality Level (AOQL).
Note 7: Dropout voltage is defined as the input to output differential at which the output voltage drops 100 mV below the value measured with a 1V differential.
Note 8: To prevent mis-operation, the Shutdown input must be driven by a signal that swings above VH and below VL with a slew rate not less than 40 mV/µs (see
Application Hints).
Note 9: Temperature coefficient is defined as the maximum (worst-case) change divided by the total temperature range.
Note 10: VFB ≤ VOUT ≤ (VIN − 1), 2.5V ≤ VIN ≤ 16V, 100 µA ≤ IL ≤ 200 mA, TJ ≤ 125˚C.
Note 11: See Typical Performance Characteristics curves.
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LP2986
Electrical Characteristics
LP2986
Typical Performance Characteristics
Unless otherwise specified: TA = 25˚C, COUT = 4.7 µF,
CIN = 2.2 µF, S/D is tied to VIN, VIN = VO(NOM) + 1V, IL = 1 mA.
VOUT vs Temperature
Dropout Voltage vs Temperature
01293508
01293509
Dropout Voltage vs Load Current
Dropout Characteristics
01293510
01293513
Ground Pin Current vs Temperature and Load
Ground Pin Current vs Load Current
01293512
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01293511
8
Unless otherwise specified: TA = 25˚C, COUT = 4.7 µF,
CIN = 2.2 µF, S/D is tied to VIN, VIN = VO(NOM) + 1V, IL = 1 mA. (Continued)
Input Current vs VIN
Input Current vs VIN
01293515
01293514
Load Transient Response
Load Transient Response
01293516
01293517
Line Transient Response
Line Transient Response
01293518
01293520
9
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LP2986
Typical Performance Characteristics
LP2986
Typical Performance Characteristics
Unless otherwise specified: TA = 25˚C, COUT = 4.7 µF,
CIN = 2.2 µF, S/D is tied to VIN, VIN = VO(NOM) + 1V, IL = 1 mA. (Continued)
Turn-On Waveform
Turn-Off Waveform
01293523
01293521
Short Circuit Current
Short Circuit Current
01293524
01293525
Short Circuit Current vs Output Voltage
Instantaneous Short Circuit Current vs Temperature
01293527
01293526
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Unless otherwise specified: TA = 25˚C, COUT = 4.7 µF,
CIN = 2.2 µF, S/D is tied to VIN, VIN = VO(NOM) + 1V, IL = 1 mA. (Continued)
DC Load Regulation
Feedback Bias Current vs Load
01293529
01293528
Feedback Bias Current vs Temperature
Shutdown Pin Current vs Shutdown Pin Voltage
01293531
01293530
Shutdown Voltage vs Temperature
Input to Output Leakage vs Temperature
01293537
01293532
11
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LP2986
Typical Performance Characteristics
LP2986
Typical Performance Characteristics
Unless otherwise specified: TA = 25˚C, COUT = 4.7 µF,
CIN = 2.2 µF, S/D is tied to VIN, VIN = VO(NOM) + 1V, IL = 1 mA. (Continued)
Output Noise Density
Output Impedance vs Frequency
01293535
01293534
Output Impedance vs Frequency
Ripple Rejection
01293536
01293533
Application Hints
Curves are provided which show the allowable ESR range
as a function of load current for various output voltages and
capacitor values (see ESR curves below).
LLP Package Devices
The LP2986 is offered in the 8 lead LLP surface mount
package to allow for increased power dissipation compared
to the SO-8 and Mini SO-8. For details on thermal performance as well as mounting and soldering specifications,
refer to Application Note AN-1187.
ESR Curves For 5V Output
EXTERNAL CAPACITORS
Like any low-dropout regulator, external capacitors are required to assure stability. These capacitors must be correctly
selected for proper performance.
INPUT CAPACITOR: An input capacitor (≥ 2.2 µF) is required between the LP2986 input and ground (amount of
capacitance may be increased without limit).
This capacitor must be located a distance of not more than
0.5” from the input pin and returned to a clean analog
ground. Any good quality ceramic or tantalum may be used
for this capacitor.
OUTPUT CAPACITOR: The output capacitor must meet the
requirement for minimum amount of capacitance and also
have an appropriate E.S.R. (equivalent series resistance)
value.
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01293506
12
ALUMINUM: The large physical size of aluminum electrolytics makes them unattractive for use with the LP2986. Their
ESR characteristics are also not well suited to the requirements of LDO regulators.
(Continued)
ESR Curves For 2.5V Output
The ESR of an aluminum electrolytic is higher than a tantalum, and it also varies greatly with temperature.
A typical aluminum electrolytic can exhibit an ESR increase
of 50X when going from 20˚C to −40˚C. Also, some aluminum electrolytics can not be used below −25˚C because the
electrolyte will freeze.
USING AN EXTERNAL RESISTIVE DIVIDER
The LP2986 output voltage can be programmed using an
external resistive divider (see Basic Application Circuits).
The resistor connected between the Feedback pin and
ground should be 51.1k. The value for the other resistor (R1)
connected between the Feedback pin and the regulated
output is found using the formula:
VOUT = 1.23 x (1 + R1/51.1k)
It should be noted that the 25 µA of current flowing through
the external divider is approximately equal to the current
saved by not connecting the internal divider, which means
the quiescent current is not increased by using external
resistors.
A lead compensation capacitor (CF) must also be used to
place a zero in the loop response at about 50 kHz. The value
for C F can be found using:
CF = 1/(2π x R1 x 50k)
01293507
IMPORTANT: The output capacitor must maintain its ESR in
the stable region over the full operating temperature range of
the application to assure stability.
The minimum required amount of output capacitance is
4.7 µF. Output capacitor size can be increased without limit.
It is important to remember that capacitor tolerance and
variation with temperature must be taken into consideration
when selecting an output capacitor so that the minimum
required amount of output capacitance is provided over the
full operating temperature range. A good Tantalum capacitor
will show very little variation with temperature, but a ceramic
may not be as good (see next section).
A good quality capacitor must be used for CF to ensure that
the value is accurate and does not change significantly over
temperature. Mica or ceramic capacitors can be used, assuming a tolerance of ± 20% or better is selected.
If a ceramic is used, select one with a temperature coefficient of NPO, COG, Y5P, or X7R. Capacitor types Z5U, Y5V,
and Z4V can not be used because their value varies more
that 50% over the −25˚C to +85˚C temperature range.
CAPACITOR CHARACTERISTICS
TANTALUM: The best choice for size, cost, and performance are solid tantalum capacitors. Available from many
sources, their typical ESR is very close to the ideal value
required on the output of many LDO regulators.
Tantalums also have good temperature stability: a 4.7 µF
was tested and showed only a 10% decline in capacitance
as the temperature was decreased from +125˚C to −40˚C.
The ESR increased only about 2:1 over the same range of
temperature.
However, it should be noted that the increasing ESR at lower
temperatures present in all tantalums can cause oscillations
when marginal quality capacitors are used (where the ESR
of the capacitor is near the upper limit of the stability range at
room temperature).
CERAMIC: For a given amount of a capacitance, ceramics
are usually larger and more costly than tantalums.
Be warned that the ESR of a ceramic capacitor can be low
enough to cause instability: a 2.2 µF ceramic was measured
and found to have an ESR of about 15 mΩ.
If a ceramic capacitor is to be used on the LP2986 output, a
1Ω resistor should be placed in series with the capacitor to
provide a minimum ESR for the regulator.
Another disadvantage of ceramic capacitors is that their
capacitance varies a lot with temperature:
Large ceramic capacitors are typically manufactured with the
Z5U temperature characteristic, which results in the capacitance dropping by a 50% as the temperature goes from 25˚C
to 80˚C.
This means you have to buy a capacitor with twice the
minimum COUT to assure stable operation up to 80˚C.
SHUTDOWN INPUT OPERATION
The LP2986 is shut off by driving the Shutdown input low,
and turned on by pulling it high. If this feature is not to be
used, the Shutdown input 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 as VH
and VL, respectively (see Electrical Characteristics).
It is also important that the turn-on (and turn-off) voltage
signals applied to the Shutdown input have a slew rate which
is not less than 40 mV/µs.
CAUTION: the regulator output state can not be guaranteed
if a slow-moving AC (or DC) signal is applied that is in the
range between VH and VL.
REVERSE INPUT-OUTPUT VOLTAGE
The PNP power transistor used as the pass element in the
LP2986 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.
13
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LP2986
Application Hints
LP2986
Application Hints
VIN to VOUT (cathode on VIN, anode on VOUT), to limit the
reverse voltage across the LP2986 to 0.3V (see Absolute
Maximum Ratings).
(Continued)
In such cases, a parasitic SCR can latch which will allow a
high current to flow into VIN (and out the ground pin), which
can damage the part.
In any application where the output may be pulled above the
input, an external Schottky diode must be connected from
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14
LP2986
Physical Dimensions
inches (millimeters)
unless otherwise noted
8-Lead Mini-Small Outline Molded Package, JEDEC
NS Package Number MUA08A
15
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LP2986
Physical Dimensions
inches (millimeters) unless otherwise noted (Continued)
8-Lead (0.150” Wide) Molded Small Outline Package, JEDEC
NS Package Number M08A
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16
inches (millimeters) unless otherwise noted (Continued)
8-Lead LLP Surface Mount Package
NS Package Number LDC08A
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LP2986 Micropower, 200 mA Ultra Low-Dropout Fixed or Adjustable Voltage Regulator
Physical Dimensions