LP2980AIM5-4.0/NOPB [TI]
4V FIXED POSITIVE LDO REGULATOR, 0.225V DROPOUT, PDSO5, SOT-23, 5 PIN;
| 型号： | LP2980AIM5-4.0/NOPB |
| 厂家： | 
TEXAS INSTRUMENTS |
| 描述： | 4V FIXED POSITIVE LDO REGULATOR, 0.225V DROPOUT, PDSO5, SOT-23, 5 PIN 光电二极管 输出元件 调节器 |
| 文件： | 总20页 (文件大小：912K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
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Texas Instruments.
Search http://www.ti.com/ for the latest technical
information and details on our current products and services.
September 2006
LP2980
Micropower 50 mA Ultra Low-Dropout Regulator In
SOT-23 and micro SMD Packages
General Description
Features
n Ultra low dropout voltage
The LP2980 is a 50 mA, fixed-output voltage regulator de-
signed specifically to meet the requirements of battery-
powered applications.
n Output voltage accuracy 0.5% (A Grade)
n Guaranteed 50 mA output current
n Smallest possible size (SOT-23, micro SMD package)
n Requires only 1 µF external capacitance
™
Using an optimized VIP (Vertically Integrated PNP) pro-
cess, the LP2980 delivers unequaled performance in all
specifications critical to battery-powered designs:
<
n
1 µA quiescent current when shutdown
@
Dropout Voltage. Typically 120 mV 50 mA load, and 7 mV
n Low ground pin current at all load currents
n High peak current capability (150 mA typical)
n Wide supply voltage range (16V max)
n Fast dynamic response to line and load
n Low ZOUT over wide frequency range
n Overtemperature/overcurrent protection
n −40˚C to +125˚C junction temperature range
@
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.
Applications
n Cellular Phone
Precision Output. 0.5% tolerance output voltages available
(A grade).
n Palmtop/Laptop Computer
n Personal Digital Assistant (PDA)
n Camcorder, Personal Stereo, Camera
5.0V, 3.3V, and 3.0V versions available as standard prod-
ucts.
Block Diagram
01207801
™
VIP is a trademark of National Semiconductor Corporation.
© 2006 National Semiconductor Corporation
DS012078
www.national.com
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
micro SMD
Function
SOT-23
VIN
GND
1
2
3
4
5
C3
A1
A3
B2
C1
Input Voltage
Common Ground (device substrate)
Logic high enable input
ON/OFF
N/C
Post package trim - do not connect to this pin
Regulated output voltage
VOUT
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
2.5
2.5
2.5
2.6
2.6
2.6
2.6
2.7
2.7
2.7
2.7
2.8
2.8
2.8
2.8
2.9
2.9
2.9
A
A
LP2980AIM5X-2.5
LP2980AIM5-2.5
LP2980IM5X-2.5
LP2980IM5-2.5
L0NA
L0NA
L0NB
L0NB
L48A
L48A
L48B
L48B
L26A
L26A
L26B
L26B
L13A
L13A
L13B
L13B
L12A
L12A
L12B
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
STD
STD
A
LP2980AIM5X-2.6
LP2980AIM5-2.6
LP2980IM5X-2.6
LP2980IM5-2.6
A
STD
STD
A
LP2980AIM5X-2.7
LP2980AIM5-2.7
LP2980IM5X-2.7
LP2980IM5-2.7
A
STD
STD
A
LP2980AIM5X-2.8
LP2980AIM5-2.8
LP2980IM5X-2.8
LP2980IM5-2.8
A
STD
STD
A
LP2980AIM5X-2.9
LP2980AIM5-2.9
LP2980IM5X-2.9
A
STD
www.national.com
2
Ordering Information (Continued)
TABLE 1. Package Marking and Order Information (Continued)
Output Voltage
(V)
Grade
Order Information
Package
Marking
L12B
L02A
L02A
L02B
L02B
L30A
L30A
L30B
L30B
L31A
L31A
L31B
L31B
L00A
L00A
L00B
L00B
L27A
L27A
L27B
L27B
L28A
L28A
L28B
L28B
L21A
L21A
L21B
L21B
L25A
L25A
L25B
L25B
L0XA
L0XA
L0XB
L0XB
L37A
L37A
L37B
L37B
L01A
L01A
L01B
L01B
Supplied as:
2.9
3.0
3.0
3.0
3.0
3.1
3.1
3.1
3.1
3.2
3.2
3.2
3.2
3.3
3.3
3.3
3.3
3.5
3.5
3.5
3.5
3.6
3.6
3.6
3.6
3.8
3.8
3.8
3.8
4.0
4.0
4.0
4.0
4.5
4.5
4.5
4.5
4.7
4.7
4.7
4.7
5.0
5.0
5.0
5.0
STD
A
LP2980IM5-2.9
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
LP2980AIM5X-3.0
LP2980AIM5-3.0
LP2980IM5X-3.0
LP2980IM5-3.0
LP2980AIM5X-3.1
LP2980AIM5-3.1
LP2980IM5X-3.1
LP2980IM5-3.1
LP2980AIM5X-3.2
LP2980AIM5-3.2
LP2980IM5X-3.2
LP2980IM5-3.2
LP2980AIM5X-3.3
LP2980AIM5-3.3
LP2980IM5X-3.3
LP2980IM5-3.3
LP2980AIM5X-3.5
LP2980AIM5-3.5
LP2980IM5X-3.5
LP2980IM5-3.5
LP2980AIM5X-3.6
LP2980AIM5-3.6
LP2980IM5X-3.6
LP2980IM5-3.6
LP2980AIM5X-3.8
LP2980AIM5-3.8
LP2980IM5X-3.8
LP2980IM5-3.8
LP2980AIM5X-4.0
LP2980AIM5-4.0
LP2980IM5X-4.0
LP2980IM5-4.0
LP2980AIM5X-4.5
LP2980AIM5-4.5
LP2980IM5X-4.5
LP2980IM5-4.5
LP2980AIM5X-4.7
LP2980AIM5-4.7
LP2980IM5X-4.7
LP2980IM5-4.7
LP2980AIM5X-5.0
LP2980AIM5-5.0
LP2980IM5X-5.0
LP2980IM5-5.0
A
STD
STD
A
A
STD
STD
A
A
STD
STD
A
A
STD
STD
A
A
STD
STD
A
A
STD
STD
A
A
STD
STD
A
A
STD
STD
A
A
STD
STD
A
A
STD
STD
A
A
STD
STD
micro SMD, 5 Bump Package (BPA05)
3.3 LP2980AIBP-3.3
A
250 Units on Tape and Reel
3
www.national.com
Ordering Information (Continued)
TABLE 1. Package Marking and Order Information (Continued)
Output Voltage
Grade
Order Information
Package
Marking
Supplied as:
(V)
3.3
3.3
3.3
5.0
5.0
5.0
5.0
A
LP2980AIBPX-3.3
LP2980IBP-3.3
LP2980IBPX-3.3
LP2980AIBP-5.0
LP2980AIBPX-5.0
LP2980IBP-5.0
LP2980IBPX-5.0
3000 Units on Tape and Reel
250 Units on Tape and Reel
3000 Units on Tape and Reel
250 Units on Tape and Reel
3000 Units on Tape and Reel
250 Units on Tape and Reel
3000 Units on Tape and Reel
STD
STD
A
A
STD
STD
www.national.com
4
Absolute Maximum Ratings (Note 1)
Power Dissipation (Note 3)
Input Supply Voltage (Survival)
Input Supply Voltage (Operating)
Shutdown Input Voltage
(Survival)
Internally Limited
−0.3V to +16V
2.1V to +16V
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
−65˚C to +150˚C
−0.3V to +16V
Output Voltage (Survival), (Note
4)
−40˚C to +125˚C
−0.3V to +9V
Lead Temperature
IOUT (Survival)
Short Circuit Protected
(Soldering, 5 sec.)
260˚C
2 kV
Input-Output Voltage (Survival),
(Note 5)
ESD Rating (Note 2)
−0.3V to +16V
Electrical Characteristics (Note 10)
Limits in standard typeface are for TJ = 25˚C, and limits in boldface type apply over the full operating temperature range. Un-
less otherwise specified: VIN = VO(NOM) + 1V, IL = 1 mA, COUT = 1 µF, VON/OFF = 2V.
Symbol
Parameter
Conditions
Typ
LP2980AI-XX
LP2980I-XX
Units
(Note 6)
(Note 6)
Min
Max
Min
Max
∆VO
Output Voltage
IL = 1 mA
−0.50
0.50
−1.0
1.0
Tolerance
%VNOM
<
<
1 mA IL 50 mA
−0.75
0.75
2.5
−1.5
1.5
3.5
−2.5
−3.5
Output Voltage
Line Regulation
VO(NOM) + 1V
≤ VIN ≤ 16V
IL = 0
0.014
0.014
0.007
%/V
mV
0.032
0.032
VIN–VO
Dropout Voltage
(Note 7)
1
3
5
3
5
IL = 1 mA
IL = 10 mA
IL = 50 mA
IL = 0
7
10
10
15
15
40
60
60
90
90
120
65
150
225
95
150
225
95
IGND
Ground Pin Current
µA
125
110
170
220
460
600
1200
1
125
110
170
220
460
600
1200
1
IL = 1 mA
IL = 10 mA
IL = 50 mA
80
140
375
<
VON/OFF 0.18V
0
1.4
0.55
0
VON/OFF
ION/OFF
ON/OFF Input Voltage
(Note 8)
High = O/P ON
Low = O/P OFF
VON/OFF = 0
1.6
1.6
V
0.18
−1
0.18
−1
ON/OFF Input Current
µA
VON/OFF = 5V
5
15
15
IO(PK)
en
Peak Output Current
Output Noise
VOUT ≥ VO(NOM) − 5%
BW = 300 Hz–50 kHz,
COUT = 10 µF
150
160
100
100
mA
µV
Voltage (RMS)
Ripple Rejection
f = 1 kHz
63
dB
COUT = 10 µF
IO(MAX)
Short Circuit Current
RL = 0 (Steady State)
(Note 9)
150
mA
5
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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, T
, the junction-to-ambient thermal resistance, θ , and
JA
J(MAX)
the ambient temperature, T . The maximum allowable power dissipation at any ambient temperature is calculated using:
A
The value of θ 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
JA
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 V and V
terminals that is normally reverse-biased. Reversing the polarity from V to V
IN OUT
IN
OUT
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 V if this function is not to be used.
IN
**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.
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6
Typical Performance Characteristics Unless otherwise specified: TA = 25˚C, VIN = VO(NOM) + 1V,
COUT = 2.2 µF, all voltage options, ON/OFF pin tied to VIN
.
Output Voltage vs
Temperature
Output Voltage vs
Temperature
01207809
01207839
Output Voltage vs
Temperature
Dropout Characteristics
01207816
01207840
Dropout Characteristics
Dropout Characteristics
01207814
01207815
7
www.national.com
Typical Performance Characteristics Unless otherwise specified: TA = 25˚C, VIN = VO(NOM) + 1V,
COUT = 2.2 µF, all voltage options, ON/OFF pin tied to VIN. (Continued)
Dropout Voltage vs
Temperature
Dropout Voltage vs
Load Current
01207811
01207820
Ground Pin Current vs
Temperature
Ground Pin Current vs
Load Current
01207819
01207810
Input Current vs VIN
Input Current vs VIN
01207818
01207817
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8
Typical Performance Characteristics Unless otherwise specified: TA = 25˚C, VIN = VO(NOM) + 1V,
COUT = 2.2 µF, all voltage options, ON/OFF pin tied to VIN. (Continued)
Line Transient Response
Load Transient Response
Load Transient Response
Line Transient Response
Load Transient Response
Load Transient Response
01207821
01207822
01207841
01207842
01207823
01207824
9
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Typical Performance Characteristics Unless otherwise specified: TA = 25˚C, VIN = VO(NOM) + 1V,
COUT = 2.2 µF, all voltage options, ON/OFF pin tied to VIN. (Continued)
Instantaneous Short Circuit Current
Short Circuit Current
vs Temperature
01207832
01207812
Instantaneous Short Circuit Current
vs Output Voltage
Short Circuit Current
01207833
01207843
Output Impedance vs
Frequency
Output Impedance vs
Frequency
01207844
01207826
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10
Typical Performance Characteristics Unless otherwise specified: TA = 25˚C, VIN = VO(NOM) + 1V,
COUT = 2.2 µF, all voltage options, ON/OFF pin tied to VIN. (Continued)
Output Noise Density
Ripple Rejection
01207825
01207827
Input to Output Leakage
vs Temperature
Output Reverse Leakage vs
Temperature
01207828
01207829
Turn-On Waveform
Turn-Off Waveform
01207830
01207831
11
www.national.com
Typical Performance Characteristics Unless otherwise specified: TA = 25˚C, VIN = VO(NOM) + 1V,
COUT = 2.2 µF, all voltage options, ON/OFF pin tied to VIN. (Continued)
ON/OFF Pin Current vs VON/OFF
01207845
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12
Application Hints
OUTPUT CAPACITOR
Multilayer Ceramic Capacitors
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.
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.
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.
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.
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.
TABLE 3. Surface-Mount Multilayer Ceramic Capacitor
Selection Guide
2.2 µF Surface-Mount Ceramic
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.
Manufacturer
Part Number
1E225ZY5U-C203
Tokin
Murata
GRM42-6Y5V225Z16
4.7 µF Surface-Mount Ceramic
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.
Manufacturer
Part Number
1E475ZY5U-C304
Tokin
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
Kemet
Part Number
T491A105M010AS
01207848
FIGURE 1. 1 µF ESR Range
NEC
NRU105M10
Siemens
Nichicon
Sprague
B45196-E3105-K
F931C105MA
293D105X0016A2T
2.2 µF Surface-Mount Tantalums
Manufacturer
Part Number
T491A225M010AS
NRU225M06
Kemet
NEC
Siemens
Nichicon
Sprague
B45196/2.2/10/10
F930J225MA
293D225X0010A2T
13
www.national.com
Application Hints (Continued)
If the output is forced above the input by more than a VBE,
this diode will become forward biased and current will flow
from the VOUT terminal to VIN. 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 VIN 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.
01207849
FIGURE 2. 2.2 µF ESR Range
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.
01207850
MICRO SMD LIGHT SENSITIVITY
FIGURE 3. 10 µF ESR Range
REVERSE CURRENT PATH
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 power transistor used in the LP2980 has an inherent
diode connected between the regulator input and output
(see below).
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.
01207834
FIGURE 4. LP2980 Reverse Current Path
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14
Typical Applications
01207851
FIGURE 5. 5V/400mA Regulator
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 VBE 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 VIN 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 VIN and IL values that may be safely used for several ambient temperatures.
01207852
FIGURE 6. Safe Operation Boundary Curves for
Figure 5
15
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Typical Applications (Continued)
01207853
@
FIGURE 7. 5V to 3.3V 3A Converter
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 VIN 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).
01207854
FIGURE 8. Heatsink Thermal Resistance Requirements for
Figure 7
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16
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.
17
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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
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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.
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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.
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device or system whose failure to perform can be reasonably
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