NSC LP2980IM5

LP2980-ADJEP
Micropower SOT, 50 mA Ultra Low-Dropout Adjustable
Voltage Regulator
General Description
Features
The LP2980-ADJEP is a 50 mA adjustable voltage regulator
designed to provide ultra low dropout in battery powered applications.
Using an optimized VIP® (vertically Integrated PNP) process,
the LP2980-ADJEP delivers unequalled performance in all
specifications critical to battery-powered designs:
Adjustable Output: output voltage can be set from 1.23V to
15V.
Precision Reference: 0.75% tolerance.
Dropout Voltage: typically 120 mV @ 50 mA load, and 7 mV
@ 1 mA load.
Ground Pin Current: typically 320 µA @ 50 mA load, and 80
µA @ 1 mA load.
Sleep Mode: less than 1 μA quiescent current when on/off
pin is pulled low.
Smallest Possible Size: SOT-23 package uses minimum
board space.
ENHANCED PLASTIC
• Extended Temperature Performance of -40°C to +125°C
• Baseline Control - Single Fab & Assembly Site
• Process Change Notification (PCN)
• Qualification & Reliability Data
• Solder (PbSn) Lead Finish is standard
• Enhanced Diminishing Manufacturing Sources (DMS)
Support
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Ultra low dropout voltage
Output adjusts from 1.23V to 15V
Guaranteed 50 mA output current
Uses tiny SOT-23 package
Requires few external components
<1 μA quiescent current when shutdown
Low ground pin current at all loads
High peak current capability (150 mA typical)
Wide supply voltage range (2.5V–16V)
Overtemperature/overcurrent protection
Applications
■ Selected Military Applications
■ Selected Avionics Applications
Order Information
PART NUMBER
VID PART NUMBER
NS PACKAGE NUMBER (Note 3)
LP2980IM5-ADJEP
V62/07601-01XA
MF05A
(Notes 1, 2)
TBD
TBD
Note 1: For the following (Enhanced Plastic) version, check for availability: LP2980IM5XADJEP
Note 2: FOR ADDITIONAL ORDERING AND PRODUCT INFORMATION, PLEASE VISIT THE ENHANCED PLASTIC WEB SITE AT: www.national.com/
mil
Note 3: Refer to package details under Physical Dimensions
VIP® is a registered trademark of National Semiconductor Corporation.
© 2007 National Semiconductor Corporation
202070
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LP2980-ADJEP Micropower SOT, 50 mA Ultra Low-Dropout Adjustable Voltage Regulator
December 2006
LP2980-ADJEP
Connection Diagram
5-Lead Small Outline Package (M5)
20207002
Top View
See NS Package Number MF05A
Block Diagram
20207001
Basic Application Circuit
20207003
*ON/OFF INPUT MUST BE ACTIVELY TERMINATED. TIE TO VIN IF THIS FUNCTION IS NOT TO BE USED.
**MINIMUM CAPACITANCE IS SHOWN TO ENSURE STABILITY OVER FULL LOAD CURRENT RANGE (SEE APPLICATION HINTS).
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2
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Storage Temperature Range
Operating Junction Temperature
Range
Lead Temp. (Soldering, 5 seconds)
ESD Rating (Note 5)
−65 to +150°C
−40 to +125°C
260°C
2 kV
Internally Limited
−0.3V to +16V
2.5V to +16V
−0.3V to +16V
−0.3V to 16V
Short Circuit Protected
−0.3V to 16V
Electrical Characteristics
(Note 13)
Limits in standard typeface are for TJ = 25°C, and limits in boldface type apply over the full operating temperature range. Unless
otherwise specified: VIN = 4.3V, VOUT = 3.3V, IL = 1 mA, CIN = 1 μF, COUT = 2.2 μF, VON/OFF = 2V.
Symbol
VREF
Parameter
Conditions
Reference Voltage
Typ
IGND
Min
Max
1.225
1.213
1.237
1 mA < IL < 50 mA
1.225
1.206
1.182
1.243
1.268
Reference Voltage Line
Regulation
2.5V ≤ VIN ≤ 16V
3
Dropout Voltage (Note 10)
IL = 0
1
3
5
IL = 1 mA
7
10
15
IL = 10 mA
40
60
90
IL = 50 mA
120
150
225
IL = 0
60
95
125
IL = 1 mA
80
110
170
IL = 10 mA
120
220
460
IL = 50 mA
320
600
1200
VOUT + 1 ≤ VIN ≤ 16V
VIN–VO
LP2980I-ADJEP (Note
9)
Ground Pin Current
6.0
15.0
VON/OFF < 0.18V
0.01
1
IADJ
ADJ Pin Bias Current
1 mA ≤ IL ≤ 50 mA
150
350
VON/OFF
ON/OFF Input Voltage
(Note 11)
High = O/P ON
1.4
Low = O/P OFF
0.55
0.18
ON/OFF Input Current
VON/OFF = 0
0.01
−1
5
15
ION/OFF
VON/OFF = 5V
IO(PK)
Peak Output Current
VOUT ≥ VO(NOM) − 5%
150
en
Output Noise Voltage (RMS)
BW = 300 Hz to 50 kHz,
COUT = 10 μF
160
Ripple Rejection
f = 1 kHz
COUT = 10 μF
68
RL = 0 (Steady State)
(Note 12)
150
IO(MAX)
Short Circuit Current
1.6
100
Units
V
mV
mV
μA
nA
V
μA
mA
μV
dB
3
mA
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LP2980-ADJEP
Power Dissipation (Note 6)
Input Supply Voltage (Survival)
Input Supply Voltage (Operating)
Shutdown Input Voltage (Survival)
Output Voltage (Survival) (Note 7)
IOUT (Survival)
Input-Output Voltage (Survival)
(Note 8)
Absolute Maximum Ratings (Note 4)
LP2980-ADJEP
Note 4: 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 5: The ESD rating of pins 3 and 4 is 1 kV.
Note 6: The maximum allowable power dissipation is a function of the maximum junction temperature, TJ(MAX), the junction-to-ambient thermal resistance, θJA, and the ambient temperature, TA. The maximum allowable power dissipation at any ambient temperature is calculated using:
The value of θJ-A for the SOT-23 package is 300°C/W. Exceeding the maximum allowable power dissipation will cause excessive die temperature, and the regulator
will go into thermal shutdown.
Note 7: If used in a dual-supply system where the regulator load is returned to a negative supply, the LP2980-ADJEP output must be diode-clamped to ground.
Note 8: The output PNP structure contains a diode between the VIN and VOUT terminals that is normally reverse-biased. Reversing the polarity from VIN to
VOUT will turn on this diode (see Application Hints).
Note 9: 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 10: 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 11: The ON/OFF input must be properly driven to prevent possible misoperation. For details, refer to Application Hints.
Note 12: See Typical Performance Characteristics curves.
Note 13: Testing and other quality control techniques are used to the extent deemed necessary to ensure product performance over the specified temperature
range. Product may not necessarily be tested across the full temperature range and all parameters may not necessarily be tested. In the absence of specific
PARAMETRIC testing, product performance is assured by characterization and/or design.
Typical Performance Characteristics Unless otherwise specified: TA = 25°C, VIN = VO(NOM) + 1V,
IL = 1 mA, ON/OFF pin tied to VIN, RADJ = 86.6k, and test circuit is as shown in Basic Application Circuit.
Output Voltage vs. Temperature
Dropout Characteristics
20207005
20207006
Dropout Voltage vs. Temperature
Dropout Voltage vs. Load Current
20207007
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20207008
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LP2980-ADJEP
Ground Pin Current vs. Temperature
Ground Pin Current vs. Load Current
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20207010
Load Transient Response
Input Current vs. VIN
20207012
20207011
Line Transient Response
Short Circuit Current
20207013
20207014
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LP2980-ADJEP
Short Circuit Current
Load Regulation
20207015
20207016
ADJ Pin Bias Current vs. Load Current
ADJ Pin Bias Current vs. Temperature
20207018
20207017
ON/OFF Threshold vs.Temperature
Output Noise Density
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LP2980-ADJEP
Ripple Rejection
20207021
Application Hints
EXTERNAL CAPACITORS
Like any low-dropout regulator, the external capacitors must
be selected carefully to assure regulator loop stability.
INPUT CAPACITOR: An input capacitor whose value is
≥1 μF is required (the amount of capacitance may be increased without limit).
Any good quality Tantalum or Ceramic capacitor may be used
here. The capacitor must be located not more than 0.5″ from
the input pin and returned to a clean analog ground.
OUTPUT CAPACITOR: The output capacitor must meet both
the requirement for minimum amount of capacitance and
E.S.R. (Equivalent Series Resistance) for stable operation.
Curves are provided below which show the allowable ESR of
the output capacitor as a function of load current for both
2.2 μF and 4.7 μF. A solid Tantalum capacitor is the best
choice for the output.
2.2 μF ESR Curves
4.7 μF ESR Curves
20207023
IMPORTANT: The output capacitor must maintain its ESR in
the stable region over the full operating temperature range to
assure stability. Also, capacitor tolerance and variation with
temperature must be considered to assure the minimum
amount of capacitance is provided at all times.
Note that this capacitor must be located not more than 0.5”
from the output pin and returned to a clean analog ground.
FEED-FORWARD CAPACITOR: A 7 pF feed-forward capacitor is required (see Basic Application Circuit). The function of this capacitor is to provide the lead compensation
necessary for loop stability.
A temperature-stable ceramic capacitor (type NPO or COG)
should be used here.
CAPACITOR CHARACTERISTICS
TANTALUM: The best capacitor choice for the LP2980-ADJEP output is solid Tantalum. The ESR of a good quality
Tantalum is almost perfectly centered in the middle of the
“stable” range of the ESR curve (about 0.5Ω–1Ω).
The temperature stability of Tantalums is typically very good,
with a total variation of only about 2:1 over the temperature
range of −40°C to +125°C (ESR increases at colder temperatures).
Off-brand capacitors should be avoided, as some poor quality
Tantalums are seen with ESR's > 10Ω, and this usually causes oscillation problems.
One caution about Tantalums if they are used on the input:
the ESR of a Tantalum is low enough that it can be destroyed
by surge current if powered up from a low impedance source
20207022
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LP2980-ADJEP
output pin and out the input pin. This current must be limited
to < 100 mA to prevent damage to the part.
The internal diode can also be turned on if the input voltage
is abruptly stepped down to a voltage which is a VBE below
the output voltage. To prevent mis-operation, an external
Schottky diode (see below) must be used in applications
where the internal diode may be turned on.
Since the external Schottky diode turns on at a lower voltage
than the internal diode, the Schottky conducts all of the current and prevents the internal diode from becoming forward
biased.
(like a battery) that has no limit on inrush current. In these
cases, use a ceramic input capacitor which does not have this
problem.
CERAMIC: Ceramics are generally larger and more costly
than Tantalums for a given amount of capacitance. Also, they
have a very low ESR which is quite stable with temperature.
Be warned that the ESR of a ceramic capacitor is typically low
enough to make an LDO oscillate: a 2.2 μF ceramic demonstrated an ESR of about 15 mΩ when tested. If used as an
output capacitor, this will cause instability (see ESR Curves).
If a ceramic is used on the output of an LDO, a small resistance (about 1Ω) should be placed in series with the capacitor. If it is used as an input capacitor, no resistor is needed as
there is no requirement for ESR on capacitors used on the
input.
EXTERNAL RESISTORS
The output voltage is set using two external resistors (see
Basic Application Circuit). It is recommended that the resistor
from the ADJ pin to ground be 51.1k.
The other resistor (RADJ) which connects between VOUT and
the ADJ pin is selected to set VOUT as given by the formula:
20207025
VOUT = 1.23 + 1.23 (RADJ/51.1k)
ON/OFF INPUT OPERATION
The LP2980-ADJEP is shut off by driving the ON/OFF input
low, and turned on by pulling the ON/OFF input high. If this
feature is not to be used, the ON/OFF input must be tied to
VIN to keep the regulator output on at all times (the ON/OFF
input must not be left floating).
To ensure proper operation, the signal source used to drive
the ON/OFF input must be able to swing above and below the
specified turn-on/turn-off voltage thresholds which guarantee
an ON or OFF state (see Electrical Characteristics).
It is also important that the turn-on (and turn-off) voltage signals applied to the ON/OFF input have a slew rate which is
greater than 40 mV/μs.
IMPORTANT: The shutdown function will not operate correctly if a slow-moving signal is used to drive the S/D input.
REVERSE CURRENT PATH
The power transistor used in the LP2980-ADJEP has an inherent diode connected between the input and output pin (see
below).
20207024
If the output is forced above the input by more than a VBE, this
diode will become forward biased and current will flow into the
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LP2980-ADJEP
Physical Dimensions inches (millimeters) unless otherwise noted
5-Lead Small Outline Package (M5)
NS Package Number MF05A
9
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LP2980-ADJEP Micropower SOT, 50 mA Ultra Low-Dropout Adjustable Voltage Regulator
Notes
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