LM2941 [NSC]
1A Low Dropout Adjustable Regulator; 1A低压降稳压器可调
| 型号： | LM2941 |
| 厂家： | 
National Semiconductor |
| 描述： | 1A Low Dropout Adjustable Regulator |
| 文件： | 总10页 (文件大小：325K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
June 1999
LM2941/LM2941C
1A Low Dropout Adjustable Regulator
automatically shut down to protect both the internal circuits
and the load. Familiar regulator features such as short circuit
and thermal overload protection are also provided.
General Description
The LM2941 positive voltage regulator features the ability to
source 1A of output current with a typical dropout voltage of
0.5V and a maximum of 1V over the entire temperature
range. Furthermore, a quiescent current reduction circuit has
been included which reduces the ground pin current when
the differential between the input voltage and the output volt-
age exceeds approximately 3V. The quiescent current with
1A of output current and an input-output differential of 5V is
therefore only 30 mA. Higher quiescent currents only exist
when the regulator is in the dropout mode (VIN − VOUT ≤ 3V).
Features
n Output voltage adjustable from 5V to 20V
=
@
n Dropout voltage typically 0.5V IO 1A
n Output current in excess of 1A
n Trimmed reference voltage
n Reverse battery protection
n Internal short circuit current limit
n Mirror image insertion protection
n P+ Product Enhancement tested
n TTL, CMOS compatible ON/OFF switch
Designed also for vehicular applications, the LM2941 and all
regulated circuitry are protected from reverse battery instal-
lations or two-battery jumps. During line transients, such as
load dump when the input voltage can momentarily exceed
the specified maximum operating voltage, the regulator will
Connection Diagram and Ordering Information
TO-220 Plastic Package
16-Lead Ceramic Dual-in-Line Package
DS008823-2
Front View
Order Number LM2941T or LM2941CT
See NS Package Number TO5A
DS008823-31
Top View
Order Number LM2941J/883
5962-9166701QEA
TO-263 Surface-Mount Package
See NS Package Number J16A
16-Lead Ceramic Surface Mount Package
DS008823-8
DS008823-9
Order Number LM2941S or LM2941CS
See NS Package Number TS5B
DS008823-32
Front View
Order Number LM2941WG/883
5962-9166701QYA
See NS Package Number WG16A
© 1999 National Semiconductor Corporation
DS008823
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Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
TO-263 (S) Package
260˚C
26V
ESD susceptibility to be determined.
Operating Ratings
Maximum Input Voltage
Temperature Range
LM2941T
Input Voltage (Survival Voltage, ≤ 100 ms)
LM2941T, LM2941S
60V
45V
LM2941CT, LM2941CS
Internal Power Dissipation (Note 3)
Maximum Junction Temperature
Storage Temperature Range
Lead Temperature
−40˚C ≤ TJ ≤ 125˚C
0˚C ≤ TJ ≤ 125˚C
−40˚C ≤ TJ ≤ 125˚C
0˚C ≤ TJ ≤ 125˚C
−55˚C ≤ TJ ≤ 125˚C
−55˚C ≤ TJ ≤ 125˚C
Internally Limited
150˚C
LM2941CT
LM2941S
−65˚C ≤ TJ ≤ +150˚C
LM2941CS
LM2941J
(Soldering, 10 seconds)
TO-220 (T) Package
LM2941WG
260˚C
Electrical Characteristics— LM2941T, LM2941S, LM2941J, LM2941WG
=
=
=
5V ≤ VO ≤ 20V, VIN VO + 5V, CO 22 µF, unless otherwise specified. Specifications in standard typeface apply for TJ
25˚C, while those in boldface type apply over the full Operating Temperature Range.
LM2941J
LM2941WG
Limit
LM2941T
LM2941S
Limit
Units
(Limits)
Parameter
Conditions
Typ
(Note 2) (Note 4)
(Note 5)
Reference Voltage
5 mA ≤ IO ≤ 1A (Note 6)
1.275
1.237/1.211
1.313/1.339
10/10
1.237/1.211
1.313/1.339
10/10
V(min)
V(max)
=
Line Regulation
Load Regulation
Output Impedance
VO + 2V ≤ VIN ≤ 26V, IO 5 mA
4
7
7
mV/V(max)
mV/V(max)
mΩ/V
50 mA ≤ IO ≤ 1A
10/10
10/10
100 mADC and 20 mArms
=
fO 120 Hz
=
<
Quiescent Current
VO + 2V ≤ VIN 26V, IO 5 mA
10
30
15/20
45/60
15/20
45/60
mA(max)
mA(max)
%
=
=
VIN VO + 5V, IO 1A
RMS Output Noise,
% of VOUT
10 Hz–100 kHz
0.003
=
IO 5 mA
=
=
Ripple Rejection
Long Term Stability
Dropout Voltage
fO 120 Hz, 1 Vrms, IL 100 mA
0.005
0.4
0.02/0.04
0.02/0.04
%/V(max)
%/1000 Hr
V(max)
=
IO 1A
0.5
0.8/1.0
200/200
1.6/1.3
60/60
0.8/1.0
200/200
1.6
=
IO 100 mA
110
1.9
mV(max)
A(min)
=
Short Circuit Current
Maximum Line
Transient
VIN max 26V (Note 7)
VO max 1V above nominal VO
75
60/60
V(min)
=
RO 100Ω, T ≤ 100 ms
Maximum Operational
Input Voltage
31
26/26
26/26
VDC
=
RO 100Ω, VO ≥ −0.6V
Reverse Polarity DC
Input Voltage
−30
−15/−15
−15/−15
V(min)
=
Reverse Polarity
Transient Input
Voltage
T ≤ 100 ms, RO 100Ω
−75
1.30
1.30
−50/−50
0.80/0.80
2.00/2.00
−50/−50
0.80/0.80
2.00/2.00
V(min)
V(max)
V(min)
ON/OFF Threshold
Voltage ON
IO ≤ 1A
IO ≤ 1A
ON/OFF Threshold
Voltage OFF
=
VON/OFF 2.0V, IO ≤ 1A
ON/OFF Threshold
Current
50
100/300
100/300
µA(max)
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2
Electrical Characteristics— LM2941CT, LM2941CS
=
=
=
5V ≤ VO ≤ 20V, VIN VO + 5V, CO 22 µF, unless otherwise specified. Specifications in standard typeface apply for TJ
25˚C, while those in boldface type apply over the full Operating Temperature Range.
Parameter
Conditions
Typ
Limit
(Note 5)
1.237/1.211
1.313/1.339
10
Units
(Limits)
V(min)
Reference Voltage
5 mA ≤ IO ≤ 1A (Note 6)
1.275
V(max)
=
Line Regulation
Load Regulation
Output Impedance
VO + 2V ≤ VIN ≤ 26V, IO 5 mA
4
7
7
mV/V(max)
mV/V(max)
mΩ/V
50 mA ≤ IO ≤ 1A
10
100 mADC and 20 mArms
=
fO 120 Hz
=
<
Quiescent Current
VO + 2V ≤ VIN 26V, IO 5 mA
10
30
15
mA(max)
mA(max)
%
=
=
VIN VO + 5V, IO 1A
45/60
RMS Output Noise,
% of VOUT
10 Hz–100 kHz
0.003
=
IO 5 mA
=
=
Ripple Rejection
Long Term Stability
Dropout Voltage
fO 120 Hz, 1 Vrms, IL 100 mA
0.005
0.4
0.02
%/V(max)
%/1000 Hr
V(max)
=
IO 1A
0.5
0.8/1.0
200/200
1.6
=
IO 100 mA
110
1.9
mV(max)
A(min)
=
Short Circuit Current
Maximum Line
Transient
VIN max 26V (Note 7)
VO max 1V above nominal VO
55
45
V(min)
=
RO 100Ω, T ≤ 100 ms
Maximum Operational Input
Voltage
31
26
VDC
=
RO 100Ω, VO ≥ −0.6V
Reverse Polarity DC Input
Voltage
−30
−15
V(min)
=
Reverse Polarity Transient
Input Voltage
T ≤ 100 ms, RO 100Ω
−55
−45
V(min)
V(max)
ON/OFF Threshold Voltage
ON
IO ≤ 1A
IO ≤ 1A
1.30
0.80
ON/OFF Threshold Voltage
OFF
1.30
2.00
V(min)
=
ON/OFF Threshold Current
VON/OFF 2.0V, IO ≤ 1A
50
100
µA(max)
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating ratings indicate conditions for which the device is in-
tended to be functional, but device parameter specifications may not be guaranteed under these conditions. For guaranteed specifications and test conditions, see
the Electrical Characteristics.
Note 2:
http://www.national.com/appinfo/milaero/index.html.
Note 3: The maximum power dissipation is a function of T (max), θ , and T . The maximum allowable power dissipation at any ambient temperature is P
A military RETS specification available upon request. For more information about military-aerospace products, see the Mil-Aero web page at
=
(T -
J
J
JA
A
D
(max) − T )/θ . If this dissipation is exceeded, the die temperature will rise above 150˚C and the LM2941 will go into thermal shutdown. For the LM2941T and
A
JA
LM2941CT, the junction-to-ambient thermal resistance (θ ) is 53˚C/W, and the junction-to-case thermal resistance (θ ) is 3˚C/W. For the LM2941K, θ is 35˚C/W
J
A
J
C
J
A
and θ is 4˚C/W. The junction-to-ambient thermal resistance of the TO-263 is 73˚C/W, and junction-to-case thermal resistance, θ is 3˚C. If the TO-263 package
JC JC
is used, the thermal resistance can be reduced by increasing the P.C. board copper area thermally connected to the package: Using 0.5 square inches of copper area,
θ
is 50˚C/W; with 1 square inch of copper area, θ is 37˚C/W; and with 1.6 or more square inches of copper area, θ is 32˚C/W.
JA JA
JA
Note 4: All limits guaranteed at room temperature (standard typeface) and at temperature extremes (boldface type). All limits are used to calculate Outgoing Quality
Level, and are 100% production tested.
Note 5: All limits guaranteed at room temperature (standard typeface) and at temperature extremes (boldface type). All room temperature limits are 100% production
tested. All limits at temperature extremes are guaranteed via correlation using standard Statistical Quality Control (SQC) methods.
Note 6: The output voltage range is 5V to 20V and is determined by the two external resistors, R1 and R2. See Typical Application Circuit.
Note 7: Output current capability will decrease with increasing temperature, but will not go below 1A at the maximum specified temperatures.
3
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Typical Performance Characteristics
Dropout Voltage
Dropout Voltage vs
Temperature
Output Voltage
DS008823-11
DS008823-13
DS008823-12
Quiescent Current vs
Temperature
Quiescent Current
Quiescent Current
DS008823-16
DS008823-15
DS008823-14
Line Transient Response
Load Transient Response
DS008823-18
DS008823-17
Ripple Rejection
Output Impedance
DS008823-19
DS008823-20
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4
Typical Performance Characteristics (Continued)
Low Voltage Behavior
Low Voltage Behavior
Output Capacitor ESR
DS008823-21
DS008823-22
DS008823-23
Output at
Output at
Peak Output Current
Voltage Extremes
Voltage Extremes
DS008823-26
DS008823-24
DS008823-25
Maximum Power
Dissipation (TO-220)
Maximum Power
Dissipation (TO-3)
Maximum Power
Dissipation
(TO-263) (Note 3)
DS008823-28
DS008823-27
DS008823-29
Line Regulation: The change in output voltage for a change
in the input voltage. The measurement is made under condi-
tions of low dissipation or by using pulse techniques such
that the average chip temperature is not significantly af-
fected.
Definition of Terms
Dropout Voltage: The input-voltage differential at which the
circuit ceases to regulate against further reduction in input
voltage. Measured when the output voltage has dropped
100 mV from the nominal value obtained at (VOUT + 5V) in-
put, dropout voltage is dependent upon load current and
junction temperature.
Load Regulation: The change in output voltage for
a
change in load current at constant chip temperature.
Long Term Stability: Output voltage stability under acceler-
ated life-test conditions after 1000 hours with maximum
rated voltage and junction temperature.
Input Voltage: The DC voltage applied to the input terminals
with respect to ground.
Input-Output Differential: The voltage difference between
the unregulated input voltage and the regulated output volt-
age for which the regulator will operate.
Output Noise Voltage: The rms AC voltage at the output,
with constant load and no input ripple, measured over a
specified frequency range.
5
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Temperature Stability of VO: The percentage change in
output voltage for a thermal variation from room temperature
to either temperature extreme.
Definition of Terms (Continued)
Quiescent Current: That part of the positive input current
that does not contribute to the positive load current. The
regulator ground lead current.
Ripple Rejection: The ratio of the peak-to-peak input ripple
voltage to the peak-to-peak output ripple voltage.
Typical Applications
5V to 20V Adjustable Regulator
DS008823-3
Note: Using 1k for R1 will ensure that the input bias current error of the adjust pin will be negligible. Do not bypass R1 or R2. This will lead to instabilities.
* Required if regulator is located far from power supply filter.
*
* C
OUT
must be at least 22 µF to maintain stability. May be increased without bound to maintain regulation during transients. Locate as close as possible to the
regulator. This capacitor must be rated over the same operating temperature range as the regulator and the ESR is critical; see curve.
1A Switch
DS008823-6
**
* To assure shutdown, select Resistor R3 to guarantee at least 300 µA of pull-up current when S1 is open. (Assume 2V at the ON/OFF pin.)
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6
Equivalent Schematic Diagram
DS008823-1
7
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Physical Dimensions inches (millimeters) unless otherwise noted
Order Number LM2941J/883
5962-9166701QEA
NS Package Number J16A
Order Number LM2941WG/883
5962-9166701QYA
NS Package Number WG16A
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8
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
Order Number LM2941T or LM2941CT
NS Package Number T05A
9
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Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
TO-263 5-Lead Plastic Surface Mount Package
Order Number LM2941S or LM2941CS
NS Package Number TS5B
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