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LP2980
Micropower 50 mA Ultra Low-Dropout Regulator In
SOT-23 and micro SMD Packages
General Description
The LP2980 is a 50 mA, fixed-output voltage regulator de-
signed specifically to meet the requirements of battery-
powered applications.
Using an optimized VIP™(Vertically Integrated PNP) pro-
cess, the LP2980 delivers unequaled performance in all
specifications critical to battery-powered designs:
Dropout Voltage. Typically 120 mV @50 mA load, and 7 mV
@1 mA load.
Ground Pin Current. Typically 375 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 and micro SMD packages
use an absolute minimum board space.
Minimum Part Count. Requires only 1 µF of external ca-
pacitance on the regulator output.
Precision Output. 0.5% tolerance output voltages available
(A grade).
5.0V, 3.3V, and 3.0V versions available as standard prod-
ucts.
Features
nUltra low dropout voltage
nOutput voltage accuracy 0.5% (A Grade)
nGuaranteed 50 mA output current
nSmallest possible size (SOT-23, micro SMD package)
nRequires only 1 µF external capacitance
n<1 µA quiescent current when shutdown
nLow ground pin current at all load currents
nHigh peak current capability (150 mA typical)
nWide supply voltage range (16V max)
nFast dynamic response to line and load
nLow Z
OUT
over wide frequency range
nOvertemperature/overcurrent protection
n−40˚C to +125˚C junction temperature range
Applications
nCellular Phone
nPalmtop/Laptop Computer
nPersonal Digital Assistant (PDA)
nCamcorder, Personal Stereo, Camera
Block Diagram
01207801
VIP™is a trademark of National Semiconductor Corporation.
September 2006
LP2980 Micropower 50 mA Ultra Low-Dropout Regulator In SOT-23 and micro SMD Packages
© 2006 National Semiconductor Corporation DS012078 www.national.com
A!
c3
M 52
Connection Diagram and Ordering Information
5-Lead Small Outline Package (M5) micro SMD, 5 Bump Package (BPA05)
01207803
Top View
See NS Package Number MF05A
For ordering information see Table 1 01207864
Note: The actual physical placement of the package marking will vary from
part to part. Package marking contains date code and lot traceability
information, and will vary considerably. Package marking does not correlate
to device type.
Top View
See NS Package Number BPA05
Pin Descriptions
Name Pin Number Function
SOT-23 micro SMD
V
IN
1 C3 Input Voltage
GND 2 A1 Common Ground (device substrate)
ON/OFF 3 A3 Logic high enable input
N/C 4 B2 Post package trim - do not connect to this pin
V
OUT
5 C1 Regulated output voltage
Ordering Information
TABLE 1. Package Marking and Order Information
Output Voltage
(V)
Grade Order Information Package
Marking
Supplied as:
5-Lead Small Outline Package (M5)
For output voltages ≤2.3V, refer to LP2980LV datasheet. If a non-standard voltage is required, see LP2980-ADJ.
2.5 A LP2980AIM5X-2.5 L0NA 3000 Units on Tape and Reel
2.5 A LP2980AIM5-2.5 L0NA 1000 Units on Tape and Reel
2.5 STD LP2980IM5X-2.5 L0NB 3000 Units on Tape and Reel
2.5 STD LP2980IM5-2.5 L0NB 1000 Units on Tape and Reel
2.6 A LP2980AIM5X-2.6 L48A 3000 Units on Tape and Reel
2.6 A LP2980AIM5-2.6 L48A 1000 Units on Tape and Reel
2.6 STD LP2980IM5X-2.6 L48B 3000 Units on Tape and Reel
2.6 STD LP2980IM5-2.6 L48B 1000 Units on Tape and Reel
2.7 A LP2980AIM5X-2.7 L26A 3000 Units on Tape and Reel
2.7 A LP2980AIM5-2.7 L26A 1000 Units on Tape and Reel
2.7 STD LP2980IM5X-2.7 L26B 3000 Units on Tape and Reel
2.7 STD LP2980IM5-2.7 L26B 1000 Units on Tape and Reel
2.8 A LP2980AIM5X-2.8 L13A 3000 Units on Tape and Reel
2.8 A LP2980AIM5-2.8 L13A 1000 Units on Tape and Reel
2.8 STD LP2980IM5X-2.8 L13B 3000 Units on Tape and Reel
2.8 STD LP2980IM5-2.8 L13B 1000 Units on Tape and Reel
2.9 A LP2980AIM5X-2.9 L12A 3000 Units on Tape and Reel
2.9 A LP2980AIM5-2.9 L12A 1000 Units on Tape and Reel
2.9 STD LP2980IM5X-2.9 L12B 3000 Units on Tape and Reel
LP2980
www.national.com 2
Ordering Information (Continued)
TABLE 1. Package Marking and Order Information (Continued)
Output Voltage
(V)
Grade Order Information Package
Marking
Supplied as:
2.9 STD LP2980IM5-2.9 L12B 1000 Units on Tape and Reel
3.0 A LP2980AIM5X-3.0 L02A 3000 Units on Tape and Reel
3.0 A LP2980AIM5-3.0 L02A 1000 Units on Tape and Reel
3.0 STD LP2980IM5X-3.0 L02B 3000 Units on Tape and Reel
3.0 STD LP2980IM5-3.0 L02B 1000 Units on Tape and Reel
3.1 A LP2980AIM5X-3.1 L30A 3000 Units on Tape and Reel
3.1 A LP2980AIM5-3.1 L30A 1000 Units on Tape and Reel
3.1 STD LP2980IM5X-3.1 L30B 3000 Units on Tape and Reel
3.1 STD LP2980IM5-3.1 L30B 1000 Units on Tape and Reel
3.2 A LP2980AIM5X-3.2 L31A 3000 Units on Tape and Reel
3.2 A LP2980AIM5-3.2 L31A 1000 Units on Tape and Reel
3.2 STD LP2980IM5X-3.2 L31B 3000 Units on Tape and Reel
3.2 STD LP2980IM5-3.2 L31B 1000 Units on Tape and Reel
3.3 A LP2980AIM5X-3.3 L00A 3000 Units on Tape and Reel
3.3 A LP2980AIM5-3.3 L00A 1000 Units on Tape and Reel
3.3 STD LP2980IM5X-3.3 L00B 3000 Units on Tape and Reel
3.3 STD LP2980IM5-3.3 L00B 1000 Units on Tape and Reel
3.5 A LP2980AIM5X-3.5 L27A 3000 Units on Tape and Reel
3.5 A LP2980AIM5-3.5 L27A 1000 Units on Tape and Reel
3.5 STD LP2980IM5X-3.5 L27B 3000 Units on Tape and Reel
3.5 STD LP2980IM5-3.5 L27B 1000 Units on Tape and Reel
3.6 A LP2980AIM5X-3.6 L28A 3000 Units on Tape and Reel
3.6 A LP2980AIM5-3.6 L28A 1000 Units on Tape and Reel
3.6 STD LP2980IM5X-3.6 L28B 3000 Units on Tape and Reel
3.6 STD LP2980IM5-3.6 L28B 1000 Units on Tape and Reel
3.8 A LP2980AIM5X-3.8 L21A 3000 Units on Tape and Reel
3.8 A LP2980AIM5-3.8 L21A 1000 Units on Tape and Reel
3.8 STD LP2980IM5X-3.8 L21B 3000 Units on Tape and Reel
3.8 STD LP2980IM5-3.8 L21B 1000 Units on Tape and Reel
4.0 A LP2980AIM5X-4.0 L25A 3000 Units on Tape and Reel
4.0 A LP2980AIM5-4.0 L25A 1000 Units on Tape and Reel
4.0 STD LP2980IM5X-4.0 L25B 3000 Units on Tape and Reel
4.0 STD LP2980IM5-4.0 L25B 1000 Units on Tape and Reel
4.5 A LP2980AIM5X-4.5 L0XA 3000 Units on Tape and Reel
4.5 A LP2980AIM5-4.5 L0XA 1000 Units on Tape and Reel
4.5 STD LP2980IM5X-4.5 L0XB 3000 Units on Tape and Reel
4.5 STD LP2980IM5-4.5 L0XB 1000 Units on Tape and Reel
4.7 A LP2980AIM5X-4.7 L37A 3000 Units on Tape and Reel
4.7 A LP2980AIM5-4.7 L37A 1000 Units on Tape and Reel
4.7 STD LP2980IM5X-4.7 L37B 3000 Units on Tape and Reel
4.7 STD LP2980IM5-4.7 L37B 1000 Units on Tape and Reel
5.0 A LP2980AIM5X-5.0 L01A 3000 Units on Tape and Reel
5.0 A LP2980AIM5-5.0 L01A 1000 Units on Tape and Reel
5.0 STD LP2980IM5X-5.0 L01B 3000 Units on Tape and Reel
5.0 STD LP2980IM5-5.0 L01B 1000 Units on Tape and Reel
micro SMD, 5 Bump Package (BPA05)
3.3 A LP2980AIBP-3.3 250 Units on Tape and Reel
LP2980
www.national.com3
Ordering Information (Continued)
TABLE 1. Package Marking and Order Information (Continued)
Output Voltage
(V)
Grade Order Information Package
Marking
Supplied as:
3.3 A LP2980AIBPX-3.3 3000 Units on Tape and Reel
3.3 STD LP2980IBP-3.3 250 Units on Tape and Reel
3.3 STD LP2980IBPX-3.3 3000 Units on Tape and Reel
5.0 A LP2980AIBP-5.0 250 Units on Tape and Reel
5.0 A LP2980AIBPX-5.0 3000 Units on Tape and Reel
5.0 STD LP2980IBP-5.0 250 Units on Tape and Reel
5.0 STD LP2980IBPX-5.0 3000 Units on Tape and Reel
LP2980
www.national.com 4
AVO
Av.“
AVow
AVW
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 Temperature
(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) 2.1V to +16V
Shutdown Input Voltage
(Survival) −0.3V to +16V
Output Voltage (Survival), (Note
4) −0.3V to +9V
I
OUT
(Survival) Short Circuit Protected
Input-Output Voltage (Survival),
(Note 5) −0.3V to +16V
Electrical Characteristics (Note 10)
Limits in standard typeface are for T
J
= 25˚C, and limits in boldface type apply over the full operating temperature range. Un-
less otherwise specified: V
IN
=V
O(NOM)
+ 1V, I
L
= 1 mA, C
OUT
= 1 µF, V
ON/OFF
= 2V.
Symbol Parameter Conditions Typ LP2980AI-XX LP2980I-XX Units
(Note 6) (Note 6)
Min Max Min Max
∆V
O
Output Voltage
Tolerance
I
L
= 1 mA −0.50 0.50 −1.0 1.0
%V
NOM
1mA<I
L
<50 mA −0.75 0.75 −1.5 1.5
−2.5 2.5 −3.5 3.5
Output Voltage V
O(NOM)
+1V 0.007 0.014 0.014 %/V
Line Regulation ≤V
IN
≤16V 0.032 0.032
V
IN
–V
O
Dropout Voltage I
L
=0 1 3 3 mV
(Note 7) 55
I
L
= 1 mA 7 10 10
15 15
I
L
=10mA 40 60 60
90 90
I
L
= 50 mA 120 150 150
225 225
I
GND
Ground Pin Current I
L
= 0 65 95 95 µA
125 125
I
L
= 1 mA 80 110 110
170 170
I
L
= 10 mA 140 220 220
460 460
I
L
= 50 mA 375 600 600
1200 1200
V
ON/OFF
<0.18V 0 11
V
ON/OFF
ON/OFF Input Voltage High = O/P ON 1.4 1.6 1.6 V
(Note 8) Low = O/P OFF 0.55 0.18 0.18
I
ON/OFF
ON/OFF Input Current V
ON/OFF
=0 0 −1 −1 µA
V
ON/OFF
=5V 5 15 15
I
O(PK)
Peak Output Current V
OUT
≥V
O(NOM)
− 5% 150 100 100 mA
e
n
Output Noise BW = 300 Hz–50 kHz, 160 µV
Voltage (RMS) C
OUT
=10µF
Ripple Rejection f=1kHz 63 dB
C
OUT
=10µF
I
O(MAX)
Short Circuit Current R
L
= 0 (Steady State)
(Note 9) 150 mA
LP2980
www.national.com5
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PROTECTWON
Electrical Characteristics (Note 10) (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 pins 3 and 4 for the SOT-23 package, or pins 5 and 2 for the micro SMD package, 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, θJA, and
the ambient temperature, TA. The maximum allowable power dissipation at any ambient temperature is calculated using:
The value of θJA for the SOT-23 package is 220˚C/W and the micro SMD package is 255˚C/W. 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 LP2980 output must be diode-clamped to ground.
Note 5: 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 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: The ON/OFF inputs must be properly driven to prevent misoperation. For details, refer to Application Hints.
Note 9: See Typical Performance Characteristics curves.
Note 10: Exposing the micro SMD device to direct sunlight will cause misoperation. See Application Hints for additional information.
Basic Application Circuit
01207802
*ON/OFF input must be actively terminated. Tie to VIN if this function is not to be used.
**Minimum Output Capacitance is 1 µF to insure stability over full load current range. More capacitance provides superior dynamic performance and additional
stability margin (see Application Hints).
***Do not make connections to this pin.
LP2980
www.national.com 6
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woo
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750725 a 25 so 75 100125 ‘50 750 725 o 25 so 75 we ‘25 Isa
IEMPERATURE (°c) TEMPERATURE ("Cl
3.015 ‘ ‘
yum : 5v , Vow * 50V
mm
EL : 5k
2 /
5 L005
)0
3.000
2.395
750 725 o 25 so 75 100125150
TEMPERATURE (0C) Vm (V)
Typical Performance Characteristics Unless otherwise specified: T
A
= 25˚C, V
IN
=V
O(NOM)
+ 1V,
C
OUT
= 2.2 µF, all voltage options, ON/OFF pin tied to V
IN
.
Output Voltage vs
Temperature
Output Voltage vs
Temperature
01207809 01207839
Output Voltage vs
Temperature Dropout Characteristics
01207840 01207816
Dropout Characteristics Dropout Characteristics
01207815 01207814
LP2980
www.national.com7
Vow (W)
Tam] (M)
In (M)
T75
T50
T25
T00
75
50
2s
a
750 725 o
700
500
Sun
too
300
200
Too
0
TmA
Loa
TEMPERATURE
om
750 725 o 25 50 75
a
25 50 75
a
(“5)
mo
TEMPERATURE (05)
T2345&
Vm (V)
7 a
IDmA
Lnad
No
Load]
T25 T50
9
IUD T25 T50
To
VDRaR (NV)
T25
T00
75
so
25
I0 20 so u:
IL(mA)
50
an
TOTmA)
o
T
TL (N)
2545675
VWTV)
9
To
Typical Performance Characteristics Unless otherwise specified: T
A
= 25˚C, V
IN
=V
O(NOM)
+ 1V,
COUT = 2.2 µF, all voltage options, ON/OFF pin tied to V
IN
. (Continued)
Dropout Voltage vs
Temperature
Dropout Voltage vs
Load Current
01207811 01207820
Ground Pin Current vs
Temperature
Ground Pin Current vs
Load Current
01207810 01207819
Input Current vs V
IN
Input Current vs V
IN
01207817 01207818
LP2980
www.national.com 8
Vum (V) Vow (V)
502 5.02
5.01 5.01
we 5 no
:99 A39
498 4,99
7 7
VIN (v) Vm (V)
s a
20 us/dw—> zu us/dW—p
3.01 3.01
Vow (V) 300 Vow (V) 300
2.99 2.99
50 50
LOAD cumm LOAD cumm
(m) (M)
0 0
mus/aw» mus/dw—p
Vow (v)
50‘ 5 01
v0“ (v) 5 co 5 on
4.55 A38
50 50
An 40
3“ so
\L (m) 1“ UN) 20
H] m
10 us/div—h m ys/div—p
Typical Performance Characteristics Unless otherwise specified: T
A
= 25˚C, V
IN
=V
O(NOM)
+ 1V,
COUT = 2.2 µF, all voltage options, ON/OFF pin tied to V
IN
. (Continued)
Line Transient Response Line Transient Response
01207821 01207822
Load Transient Response Load Transient Response
01207841 01207842
Load Transient Response Load Transient Response
01207823 01207824
LP2980
www.national.com9
\/‘N = sv
300 ouTPuT SHORYED To sum
ATTIME\= a
200
‘5; (um)
um
warns/div»
v‘N - Tsv
OUTPUT SHURTED To GND
AT TM « : u
THERMAL
CYCUNG
20 ms/dw »
u as
0.0T
0.003
OUTPUI \MFEDANCE (n)
IO Too w mu Tank 1»
FREQUENCY (Hz)
\Sc (mA) ‘sc (M)
OUTPUI \MFEDANCE (n)
350
325
300
275
250
225
2w
750 725 u 25 so 75 we 125 T50
360
340
320
300
230
260
3a
m
v.3
0,1
u as
0.0T
0.003
TEMPERATURE (°C)
Vow : 3v
‘fi‘ml Iumu TH
Cowl?” V'MA
mm can =Hur
Tmm
cW:Taur
\zSflmA
cm": WW
Vsnm
Cow? 2»;
lo 100 w wk mm m
FREQUENCY (Hz)
Typical Performance Characteristics Unless otherwise specified: T
A
= 25˚C, V
IN
=V
O(NOM)
+ 1V,
COUT = 2.2 µF, all voltage options, ON/OFF pin tied to V
IN
. (Continued)
Short Circuit Current
Instantaneous Short Circuit Current
vs Temperature
01207832 01207812
Short Circuit Current
Instantaneous Short Circuit Current
vs Output Voltage
01207833
01207843
Output Impedance vs
Frequency
Output Impedance vs
Frequency
01207844 01207826
LP2980
www.national.com 10
10
TL sum, cW WMF
g 1 : E§
> /
3 IL TmA, cw, : my
3 u.T 7 IL : ““ch = 22w
Z sum, em = 2.2M
um
um wan quuu Toucan
EREouEch (Hz)
VON/DEF ’ U
OUTPUT cuRNEcTEu To GND
’2 Vw : 5V
3
E
8
750 725 u 25 so 75 Too T25 T50
TEMPERATURE (°C)
5
VOL" (v)
Von/arr (V)
5V
av
20 ys/dw—p
E
3 mA
§ 6 m : 10 M
E T so MA
cWI : 2.2 ,4:
IL = so mA
IO 100 w mu Tank 1»
FREQUENCY (HZ)
Izou
(nu/arr m WW pws mm
3 vw, EDNNECYED m 5v mwz SOURCE.
V was
3 son
E 600 \
8 \
we
750 725 u 25 an 75 Too T25 T50
TEMPERATURE (°C)
5
van (v)
Von/arr (V)
5
av
Toms/aw»
Typical Performance Characteristics Unless otherwise specified: T
A
= 25˚C, V
IN
=V
O(NOM)
+ 1V,
COUT = 2.2 µF, all voltage options, ON/OFF pin tied to V
IN
. (Continued)
Output Noise Density Ripple Rejection
01207827 01207825
Input to Output Leakage
vs Temperature
Output Reverse Leakage vs
Temperature
01207828 01207829
Turn-On Waveform Turn-Off Waveform
01207830 01207831
LP2980
www.national.com11
nz¢sawmuw
VoN/arr (V)
Typical Performance Characteristics Unless otherwise specified: T
A
= 25˚C, V
IN
=V
O(NOM)
+ 1V,
COUT = 2.2 µF, all voltage options, ON/OFF pin tied to V
IN
. (Continued)
ON/OFF Pin Current vs V
ON/OFF
01207845
LP2980
www.national.com 12
qu
w
m 51AM Maw
g
3 0‘
0,01
CL = wr
740°csllsuz5°c
mom
o la zu 30 A0 50
LOAD CURRENT (ma)
Application Hints
OUTPUT CAPACITOR
Like any low-dropout regulator, the LP2980 requires an out-
put capacitor to maintain regulator loop stability. This capaci-
tor must be selected to meet the requirements of minimum
capacitance and equivalent series resistance (ESR) range. It
is not difficult to find capacitors which meet the criteria of the
LP2980, as the acceptable capacitance and ESR ranges are
wider than for most other LDOs.
In general, the capacitor value must be at least 1 µF (over
the actual ambient operating temperature), and the ESR
must be within the range indicated in Figures 1, 2 and Figure
3. It should be noted that, although a maximum ESR is
shown in these Figures, it is very unlikely to find a capacitor
with ESR that high.
Tantalum Capacitors
Surface-mountable solid tantalum capacitors offer a good
combination of small physical size for the capacitance value,
and ESR in the range needed by the LP2980.
The results of testing the LP2980 stability with surface-
mount solid tantalum capacitors show good stability with
values of at least 1 µF. The value can be increased to 2.2 µF
(or more) for even better performance, including transient
response and noise.
Small value tantalum capacitors that have been verified as
suitable for use with the LP2980 are shown in Table 2.
Capacitance values can be increased without limit.
Aluminum Electrolytic Capacitors
Although probably not a good choice for a production design,
because of relatively large physical size, an aluminum elec-
trolytic capacitor can be used in the design prototype for an
LP2980 regulator. A value of at least 1 µF should be used,
and the ESR must meet the conditions of Figures 1, 2 and
Figure 3. If the operating temperature drops below 0˚C, the
regulator may not remain stable, as the ESR of the alumi-
num electrolytic capacitor will increase, and may exceed the
limits indicated in the Figures.
TABLE 2. Surface-Mount Tantalum Capacitor
Selection Guide
1 µF Surface-Mount Tantalums
Manufacturer Part Number
Kemet T491A105M010AS
NEC NRU105M10
Siemens B45196-E3105-K
Nichicon F931C105MA
Sprague 293D105X0016A2T
2.2 µF Surface-Mount Tantalums
Manufacturer Part Number
Kemet T491A225M010AS
NEC NRU225M06
Siemens B45196/2.2/10/10
Nichicon F930J225MA
Sprague 293D225X0010A2T
Multilayer Ceramic Capacitors
Surface-mountable multilayer ceramic capacitors may be an
attractive choice because of their relatively small physical
size and excellent RF characteristics. However, they some-
times have ESR values lower than the minimum required by
the LP2980, and relatively large capacitance change with
temperature. The manufacturer’s datasheet for the capacitor
should be consulted before selecting a value.
Test results of LP2980 stability using multilayer ceramic
capacitors show that a minimum value of 2.2 µF is usually
needed for the 5V regulator. For the lower output voltages, or
for better performance, a higher value should be used, such
as 4.7 µF.
Multilayer ceramic capacitors that have been verified as
suitable for use with the LP2980 are shown in Table 3.
TABLE 3. Surface-Mount Multilayer Ceramic Capacitor
Selection Guide
2.2 µF Surface-Mount Ceramic
Manufacturer Part Number
Tokin 1E225ZY5U-C203
Murata GRM42-6Y5V225Z16
4.7 µF Surface-Mount Ceramic
Manufacturer Part Number
Tokin 1E475ZY5U-C304
01207848
FIGURE 1. 1 µF ESR Range
LP2980
www.national.com13
55R (11)
[SR (n)
ma
ID
SHELF. REG‘ON
I n
0 V
0.01
cL : 2.2 yr
40°C: ”gems“:
u om
o m 20 30
LOAD CURRENT (ma)
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sum: eroN
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0 1
n m
<:l :="" mur="" 40°c:="" i,="" snzsnc="" n="" om="" 0="" io="" 20="" 30="" load="" current="" (ma)="" au="" a0="" 50="" sd="">Application Hints (Continued)
REVERSE CURRENT PATH
The power transistor used in the LP2980 has an inherent
diode connected between the regulator input and output
(see below).
If the output is forced above the input by more than a V
BE
,
this diode will become forward biased and current will flow
from the V
OUT
terminal to V
IN
. No damage to the LP2980 will
occur under these conditions as long as the current flowing
into the output pin does not exceed 100 mA.
ON/OFF INPUT OPERATION
The LP2980 is shut off by pulling the ON/OFF input low, and
turned on by driving the input high. If this feature is not to be
used, the ON/OFF input should be tied to V
IN
to keep the
regulator 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 guar-
antee an ON or OFF state (see Electrical Characteristics).
The ON/OFF signal may come from either a totem-pole
output, or an open-collector output with pull-up resistor to the
LP2980 input voltage or another logic supply. The high-level
voltage may exceed the LP2980 input voltage, but must
remain within the Absolute Maximum Ratings for the ON/
OFF pin.
It is also important that the turn-on/turn-off voltage signals
applied to the ON/OFF input have a slew rate which is
greater than 40 mV/µs.
Important: the regulator shutdown function will operate incor-
rectly if a slow-moving signal is applied to the ON/OFF input.
MICRO SMD MOUNTING
The micro SMD package requires specific mounting tech-
niques which are detailed in National Semiconductor Appli-
cation Note # 1112. Referring to the section Surface Mount
Technology (SMT) Assembly Considerations, it should be
noted that the pad style which must be used with the 5-pin
package is the NSMD (non-solder mask defined) type.
For best results during assembly, alignment ordinals on the
PC board may be used to facilitate placement of the micro
SMD device.
MICRO SMD LIGHT SENSITIVITY
Exposing the micro SMD device to direct sunlight will cause
misoperation of the device. Light sources such as Halogen
lamps can also affect electrical performance if brought near
to the device.
The wavelenghts which have the most detrimental effect are
reds and infra-reds, which means that the fluorescent light-
ing used inside most buildings has very little effect on per-
formance. A micro SMD test board was brought to within 1
cm of a fluorescent desk lamp and the effect on the regu-
lated output voltage was negligible, showing a deviation of
less than 0.1% from nominal.
01207849
FIGURE 2. 2.2 µF ESR Range
01207850
FIGURE 3. 10 µF ESR Range
01207834
FIGURE 4. LP2980 Reverse Current Path
LP2980
www.national.com 14
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2mm}
546 vac (Note 9)
NWT W W”
(Nate E) 100 \L :400 m»: (max)
(Note E)
oN/uTr * m
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LPZQEOiS (Notes an)
6ND
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OPERAHNG PmNT MUST L
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mA
Typical Applications
The LP2980 can be used to control higher-current regulators, by adding an external PNP pass device. With the PNP transistors
shown in , the output current can be as high as 400 mA, as long as the input voltage is held within the Safe Operation Boundary
Curves shown below in.
To ensure regulation, the minimum input voltage of this regulator is 6V. This “headroom” is the sum of the V
BE
of the external
transistor and the dropout voltage of the LP2980.
Notes:
A. Drive this input with a logic signal (see Application Hints). If the shutdown function is not to be used, tie the ON/OFF pin directly
to the V
IN
pin.
B. Recommended devices (other PNP transistors can be used if the current gain and voltage ratings are similar).
C. Capacitor is required for regulator stability. Minimum size is shown, and may be increased without limit.
D. Increasing the output capacitance improves transient response and increases phase margin.
E. Maximum safe input voltage and load current are limited by power dissipation in the PNP pass transistor and the maximum
ambient temperature for the specific application. If a TO-92 transistor such as the MPS2907A is used, the thermal resistance from
junction-to-ambient is 180˚C/W in still air.
Assuming a maximum allowable junction temperature of 150˚C for the MPS2907A device, the following curves show the
maximum V
IN
and I
L
values that may be safely used for several ambient temperatures.
01207851
FIGURE 5. 5V/400mA Regulator
01207852
FIGURE 6. Safe Operation Boundary Curves for
Figure 5
LP2980
www.national.com15
msHs
mm D)
VOUT
3,3V :2 3A (max)
7 VM
ON/OFF V ¢ 22 HF
OUT Yenla‘um
w} , LPZBEOiS 3 (Wm; 3,0]
TumaluWZ:
(Nan: B) GND
GND
uC/W
so
50
A0
30
20
“WW ALLOWAELE HEATS‘NK
THERMAL RES‘STANCE
Typical Applications (Continued)
With limited input voltage range, the LP2980 can control a 3.3V, 3A regulator with the use of a high current-gain external PNP
pass transistorias shown in . If the regulator is to be loaded with the full 3A, heat sinking will be required on the pass transistor
to keep it within its rated temperature range. Refer to the Heatsink Thermal Resistance Requirements, below. For best load
regulation at the high load current, the LP2980 output voltage connection should be made as close to the load as possible.
Although this regulator can handle a much higher load current than can the LP2980 alone, it can be shut down in the same
manner as the LP2980. When the ON/OFF control is brought low, the converter will be in shutdown, and will draw less than 1 µA
from the source.
Notes:
A. Drive this input with a logic signal (see Application Hints). If the shutdown function is not to be used, tie the ON/OFF pin directly
to the V
IN
pin.
B. Capacitor is required for regulator stability. Minimum size is shown, and may be increased without limit.
C. Increasing the output capacitance improves transient response and increases phase margin.
D. A heatsink may be required for this transistor. The maximum allowable value for thermal resistance of the heatsink is
dependent on ambient temperature and load current (see curves in ). Once the value is obtained from the graph, a heatsink must
be selected which has a thermal resistance equal to or lower than this value. If the value is above 60˚C/W, no heatsink is required
(the TO-220 package alone will safely dissipate this).
For these curves, a maximum junction temperature of 150˚C is assumed for the pass transistor. The case-to-heatsink attachment
thermal resistance is assumed to be 1.5˚C/W. All calculations are for 5.5V input voltage (which is worst-case for power
dissipation).
01207853
FIGURE 7. 5V to 3.3V @3A Converter
01207854
FIGURE 8. Heatsink Thermal Resistance Requirements for
Figure 7
LP2980
www.national.com 16
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am no: ‘
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MFusMRevC)
Physical Dimensions inches (millimeters) unless otherwise noted
5-Lead Small Outline Package (M5)
NS Package Number MF05A
For Order Numbers, refer to Table 1 in the “Order Information” section of this document.
LP2980
www.national.com17
riwuswfi
‘ m 5W ‘
‘ Q
;. m .w L. ‘
mm mum WNDMION
mi 5m: mum
umnsmus ARE IN MILUMEIEKS
wusmns W Max mmm mm
X:
mm H coma
5mm
aw
smoaxxx (Rev D)
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
NOTES: UNLESS OTHERWISE SPECIFIED
1. EPOXY COATING
2. 63Sn/37Pb EUTECTIC BUMP
3. RECOMMEND NON-SOLDER MASK DEFINED LANDING PAD.
4. PIN 1 IS ESTABLISHED BY LOWER LEFT CORNER WITH RESPECT TO TEXT ORIENTATION. REMAINING PINS ARE NUMBERED COUNTER
CLOCKWISE.
5. XXX IN DRAWING NUMBER REPRESENTS PACKAGE SIZE VARIATION WHERE X1 IS PACKAGE WIDTH, X2 IS PACKAGE LENGTH AND X3 IS
PACKAGE HEIGHT.
6.NO JEDEC REGISTRATION AS OF AUG.1999.
micro SMD, 5 Bump Package (BPA05)
NS Package Number BPA05A
For Order Numbers, refer to Table 1 in the “Order Information” section of this document.
The dimensions for X1, X2 and X3 are as given:
X1 = 0.930 +/− 0.030mm
X2 = 1.107 +/− 0.030mm
X3 = 0.850 +/− 0.050mm
LP2980
www.national.com 18
Notes
National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves
the right at any time without notice to change said circuitry and specifications.
For the most current product information visit us at www.national.com.
LIFE SUPPORT POLICY
NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS
WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR
CORPORATION. As used herein:
1. Life support devices or systems are devices or systems
which, (a) are intended for surgical implant into the body, or
(b) support or sustain life, and whose failure to perform when
properly used in accordance with instructions for use
provided in the labeling, can be reasonably expected to result
in a significant injury to the user.
2. A critical component is any component of a life support
device or system whose failure to perform can be reasonably
expected to cause the failure of the life support device or
system, or to affect its safety or effectiveness.
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www.national.com
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