LP2983
LP2983 Micropower 150 mA Voltage Regulator in SOT-23 Package For Output
Voltages1.2V Designed for Use with Very Low ESR Output Capacitors
Literature Number: SNVS170B
January 16, 2009
LP2983
Micropower 150 mA Voltage Regulator in SOT-23 Package
For Output Voltages ≤ 1.2V
Designed for Use with Very Low ESR Output Capacitors
General Description
The LP2983 is a 150 mA, fixed-output voltage regulator de-
signed to provide tight voltage regulation in applications with
output voltages ≤ 1.2V.
Using an optimized VIP® (Vertically Integrated PNP) process,
the LP2983 delivers unequalled performance in all critical
specifications:
Ground Pin Current: Typically 825 µA @ 150 mA load, and
75 µA @ 1 mA load.
Enhanced Stability: The LP2983 is stable with output ca-
pacitor ESR down to zero, which allows the use of ceramic
capacitors on the output.
Smallest Possible Size: SOT-23 package uses absolute
minimum board space.
Precision Output: 1% tolerance output voltages available (A
grade).
Features
■Guaranteed 150 mA output current
■Smallest possible size (SOT-23 package)
■Requires minimum external components
■Stable with low-ESR output capacitor
■Low ground pin current at all loads
■Output voltage accuracy 1% (A Grade)
■High peak current capability
■Wide supply voltage range (16V max)
■Low ZOUT: 0.3Ω typical (10 Hz to 1 MHz)
■Overtemperature/overcurrent protection
■−40°C to +125°C junction temperature range
Applications
■Cellular Phone
■Palmtop/Laptop Computer
■Personal Digital Assistant (PDA)
■Camcorder, Personal Stereo, Camera
Block Diagram
20029101
VIP® is a registered trademark of National Semiconductor Corporation.
© 2009 National Semiconductor Corporation 200291 www.national.com
LP2983 Micropower 150 mA Voltage Regulator in SOT-23 Package For Output Voltages ≤ 1.2V
Connection Diagram
5-Lead Small Outline Package (SOT-23)
20029103
Top View
See NS Package Number MF05A
Pin Descriptions
Pin Pin
Number Function
VIN 1 Input Voltage
GND 2 Common Ground (device substrate)
ON/OFF 3 Logic high enable input
ESR 4 Low side connection for low-ESR output capacitors
VOUT 5 Regulated Output Voltage
Ordering Information
TABLE 1. Package Marking and Ordering Information
Output
Voltage (V) Grade Order
Information
Package
Marking Supplied as:
1.0
ALP2983AIM5X-1.0 LENA 3000 Units on Tape and Reel
LP2983AIM5-1.0 LENA 1000 Units on Tape and Reel
STD LP2983IM5X-1.0 LENB 3000 Units on Tape and Reel
LP2983IM5-1.0 LENB 1000 Units on Tape and Reel
1.2
ALP2983AIM5X-1.2 LELA 3000 Units on Tape and Reel
LP2983AIM5-1.2 LELA 1000 Units on Tape and Reel
STD LP2983IM5X-1.2 LELB 3000 Units on Tape and Reel
LP2983IM5-1.2 LELB 1000 Units on Tape and Reel
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LP2983
Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Storage Temperature Range −65°C to +150°C
Operating Junction Temperature
Range −40°C to +125°C
Lead Temp. (Soldering, 5 sec.) 260°C
ESD Rating (Note 2) 2 kV
Power Dissipation (Note 3) Internally Limited
Input Supply Voltage (Survival) −0.3V to +16V
Input Supply Voltage (Operating) 2.2V to +16V
Shutdown Input Voltage (Survival) −0.3V to +16V
Output Voltage Survival, (Note 4) −0.3V to +9V
IOUT (Survival) Short Circuit
Protected
Input-Output Voltage Survival,(Note 5) −0.3V to +16V
Electrical Characteristics
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 = VO(NOM) + 1V, IL = 1 mA, CIN = 1 µF, COUT = 2.2 µF, VON/OFF = 2V.
Symbol Parameter Conditions Typ
LP2983AI-X.X LP2983I-X.X
Units
(Note 6) (Note 6)
Min Max Min Max
ΔVOOutput Voltage
Tolerance
−1.0 1.0 −1.5 1.5
%
1 mA ≤ IL ≤ 50 mA −2.0 2.0 −2.5 2.5
−2.5 2.5 −3.5 3.5
1 mA ≤ IL ≤ 150 mA −2.5 2.5 −3.0 3.0
−3.5 3.5 −4.0 4.0
Output Voltage VO(NOM)+1V ≤ VIN ≤ 16V 0.01 0.016 0.016
%/V
Line Regulation 0.032 0.032
IGND Ground Pin Current IL = 0 65 95 95
µA
125 125
IL = 1 mA 75 110 110
170 170
IL = 10 mA 120 220 220
400 400
IL = 50 mA 300 500 500
900 900
IL = 150 mA 825 1200 1500
2000 2000
VON/OFF < 0.15V 6 12 12
VON/OFF < 0.05V 0.2 2 2
VIN(min) Minimum VIN required to
maintain Output
Regulation
2.05 2.20 2.20
V
VON/OFF ON/OFF Input Voltage
(Note 7)
High = O/P ON 1.4 1.6 1.6
Low = O/P OFF 0.1 0.05 0.05
ION/OFF ON/OFF Input Current VON/OFF = 0 0.01 −2 −2 µA
VON/OFF = 5V 5 15 15
enOutput Noise BW = 10 Hz to 100 kHz,
Voltage (RMS) COUT = 10 µF 60 µV
VOUT = 1.2V
Ripple Rejection f = 1 kHz
65
dB
COUT = 2.2 µF
IO(SC) Short Circuit Current RL = 0 (Steady State) 400
mA
(Note 8)
IO(PK) Peak Output Current VOUT ≥ Vo(NOM) −5% 250
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LP2983
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 pin 3 is 1 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 temperture is calculated using:
Where the value of θJ-A for the SOT-23 package is 240°C/W in a typical PC board mounting. Exceeding the maximum allowable 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 LP2983 output must be diode-clamped to ground.
Note 5: The output PNP structure contains a diode between the VIN to VOUT terminals that is normally reverse-biased. Reversing the polarity from VIN to VOUT
will turn on this diode and possibly cause a destructive latch-up condition (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: The ON/OFF input must be properly driven to prevent possible misoperation. For details, refer to Application Hints.
Note 8: The LP2983 has foldback current limiting which allows a high peak current when VOUT > 0.5V, and then reduces the maximum output current as VOUT is
forced down to ground (see Typical Performance Characteristics curves).
Typical Application Circuit
20029102
*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 (may be increased without limit). Ceramic capacitor required for output (see Application Hints).
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LP2983
Typical Performance Characteristics Unless otherwise specified: CIN = 1µF, COUT = 2.2µF, VIN = VOUT
(NOM) +1, TA = 25°C, ON/OFF pin is tied to VIN.
LP2983 Tempco
20029107
Minimum Input Voltage vs Temperature
20029108
Input Current vs VIN (0mA Load)
20029109
Input Current vs VIN (1mA Load)
20029110
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LP2983
Input Current vs VIN (50mA & 150mA Loads)
20029111
GND Pin vs Load Current
20029112
GND Pin vs Temperature and Load
20029113
Line Transient Response
ΔVIN = 1V, Load = 1mA
20029114
Line Transient Response
ΔVIN = 1V, Load = 150mA
20029115
Line Transient Response
ΔVIN = 13.8V, Load = 1mA
20029116
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LP2983
Line Transient Response
ΔVIN = 13.8V, Load = 150mA
20029117
Noise Density
20029118
Ripple Rejection COUT = 2.2µF
20029119
Turn-On Time
20029121
Short Circuit Current vs Temperature
20029127
Short Circuit Current, VIN = 16V
20029122
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LP2983
Short Circuit Current, VIN = 2.8V
20029123
Short Circuit Current, VIN = 6V
20029124
Load Transient Response
COUT = 4.7µF
20029125
Load Transient Response
COUT = 2.2µF
20029126
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LP2983
Application Hints
EXTERNAL CAPACITORS
Like any low-dropout regulator, the LP2983 requires external
capacitors for regulator stability. These capacitors must be
correctly selected for good performance.
Input Capacitor
An input capacitor whose capacitance is ≥ 1 µF is required
between the LP2983 input and ground (the amount of capac-
itance 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.
Important: Tantalum capacitors can suffer catastrophic fail-
ure due to surge current when connected to a low-impedance
source of power (like a battery or very large capacitor). If a
Tantalum capacitor is used at the input, it must be guaranteed
by the manufacturer to have a surge current rating sufficient
for the application.
There are no requirements for ESR on the input capacitor, but
tolerance and temperature coefficient must be considered
when selecting the capacitor to ensure the capacitance will
be ≥ 1 µF over the entire operating temperature range.
Output Capacitor
The LP2983 is designed specifically to work with ceramic out-
put capacitors, utilizing 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 zero ohms.
The ceramic output capacitor must be connected between the
VOUT pin (device pin 5) and the ESR pin (device pin 4).
See Figure 1 below.
COUT = 2.2µF
Ceramic to ESR Pin
20029120
FIGURE 1.
The LP2983 requires a minimum of 2.2 µF on the output (out-
put capacitor size can be increased without limit).
It is important to remember that capacitor tolerance and vari-
ation 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 oper-
ating temperature range. It should be noted that ceramic
capacitors can exhibit large changes in capacitance with tem-
perature (see next section, Capacitor Characteristics).
The output capacitor must be located not more than 1 cm from
the output pin and returned to a clean analog ground via the
ESR pin.
CAPACITOR CHARACTERISTICS
The LP2983 was designed to work with ceramic capacitors
on the output to take advantage of the benefits they offer: for
capacitance values in the 2.2 µF to 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).
One disadvantage of ceramic capacitors is that their capaci-
tance can vary with temperature. Most 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 2.2 µF capacitor were used on
the output since it will drop down to approximately 1 µF at high
ambient temperatures (which could cause the LP2983 to os-
cillate). If Z5U or Y5V capacitors are used on the output, a
minimum capacitance value of 4.7 µF must be observed.
A better choice for temperature coefficient in ceramic capac-
itors is X7R, which holds the capacitance within ±15%. Un-
fortunately, the larger values of capacitance are not offered
by all manufacturers in the X7R dielectric.
ON/OFF INPUT OPERATION
The LP2983 is shut off by driving the ON/OFF input low, and
turned on by pulling it high. If this feature is not to be used,
the ON/OFF 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 ON/OFF input must be able to swing above and below the
specified turn-on/turn-off voltage thresholds listed in the Elec-
trical Characteristics section under VON/OFF. To prevent mis-
operation, the turn-on (and turn-off) voltage signals applied to
the ON/OFF input must have a slew rate which is
≥ 40 mV/µs.
Caution: The regulator output voltage can not be guaranteed
if a slow-moving AC (or DC) signal is applied that is in the
range between the specified turn-on and turn-off voltages list-
ed under the electrical specification VON/OFF (see Electrical
Characteristics).
REVERSE INPUT-OUTPUT VOLTAGE
The internal PNP power transistor used as the pass element
in the LP2983 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 re-
verse biased (See Figure 2).
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LP2983
20029144
FIGURE 2. LP2983 Reverse Current Path
However, if the input voltage is more than a VBE below the
output voltage, this diode will turn ON and current will flow into
the regulator output. In such cases, a parasitic SCR can latch
which will allow a high current to flow into the VIN pin and out
the ground pin, which can damage 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.
In any application where the output voltage may be higher
than the input voltage, an external Schottky diode must be
connected from VIN to VOUT (cathode on VIN, anode on
VOUT. See Figure 3), to limit the reverse voltage across the
LP2982 to 0.3V (see Absolute Maximum Ratings).
20029145
FIGURE 3. Adding External Schottky Diode Protection
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LP2983
Notes
LP2983 Micropower 150 mA Voltage Regulator in SOT-23 Package For Output Voltages ≤ 1.2V
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