LM7912MDC [TI]
IC,VOLT REGULATOR,FIXED,-12V,BIPOLAR,DIE;
| 型号： | LM7912MDC |
| 厂家： | 
TEXAS INSTRUMENTS |
| 描述： | IC,VOLT REGULATOR,FIXED,-12V,BIPOLAR,DIE |
| 文件： | 总10页 (文件大小：181K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
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September 2001
LM79XX Series
3-Terminal Negative Regulators
resistor divider. The low quiescent current drain of these
devices with a specified maximum change with line and load
ensures good regulation in the voltage boosted mode.
General Description
The LM79XX series of 3-terminal regulators is available with
fixed output voltages of −5V, −12V, and −15V. These devices
need only one external component—a compensation ca-
pacitor at the output. The LM79XX series is packaged in the
TO-220 power package and is capable of supplying 1.5A of
output current.
For applications requiring other voltages, see LM137
datasheet.
Features
n Thermal, short circuit and safe area protection
n High ripple rejection
These regulators employ internal current limiting safe area
protection and thermal shutdown for protection against vir-
tually all overload conditions.
n 1.5A output current
n 4% tolerance on preset output voltage
Low ground pin current of the LM79XX series allows output
voltage to be easily boosted above the preset value with a
Connection Diagrams
Typical Applications
TO-220 Package
Fixed Regulator
DS007340-3
DS007340-14
*
Required if regulator is separated from filter capacitor by
more than 3". For value given, capacitor must be solid
tantalum. 25µF aluminum electrolytic may be substituted.
Front View
Order Number LM7905CT, LM7912CT or LM7915CT
See NS Package Number TO3B
†
Required for stability. For value given, capacitor must be
solid tantalum. 25µF aluminum electrolytic may be substi-
tuted. Values given may be increased without limit.
For output capacitance in excess of 100µF, a high current
diode from input to output (1N4001, etc.) will protect the
regulator from momentary input shorts.
© 2001 National Semiconductor Corporation
DS007340
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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.
Input-Output Differential
(Vo = −5V)
25V
30V
(Vo = −12V and −15V)
Power Dissipation (Note 2)
Operating Junction Temperature Range
Storage Temperature Range
Lead Temperature (Soldering, 10 sec.)
Internally Limited
0˚C to +125˚C
−65˚C to +150˚C
230˚C
Input Voltage
(Vo = −5V)
−25V
−35V
(Vo = −12V and −15V)
Electrical Characteristics
Conditions unless otherwise noted: IOUT = 500mA, CIN = 2.2µF, COUT = 1µF, 0˚C ≤ TJ ≤ +125˚C, Power Dissipation ≤ 1.5W.
Part Number
Output Voltage
LM7905C
−5V
Units
Input Voltage (unless otherwise specified)
−10V
Typ
Symbol
Parameter
Output Voltage
Conditions
Min
−4.8
Max
−5.2
VO
TJ = 25˚C
−5.0
V
V
5mA ≤ IOUT ≤ 1A,
P ≤ 15W
−4.75
−5.25
(−20 ≤ VIN ≤ −7)
V
∆VO
∆VO
Line Regulation
Load Regulation
TJ = 25˚C, (Note 3)
8
50
15
mV
V
(−25 ≤ VIN ≤ −7)
2
mV
V
(−12 ≤ VIN ≤ −8)
TJ = 25˚C, (Note 3)
5mA ≤ IOUT ≤ 1.5A
250mA ≤ IOUT ≤ 750mA
TJ = 25˚C
15
5
100
50
2
mV
mV
mA
mA
V
IQ
Quiescent Current
Quiescent Current
Change
1
∆IQ
With Line
0.5
(−25 ≤ VIN ≤ −7)
With Load, 5mA ≤ IOUT ≤ 1A
TA = 25˚C, 10Hz ≤ f ≤ 100Hz
f = 120Hz
0.5
mA
µV
dB
V
Vn
Output Noise Voltage
Ripple Rejection
125
54
66
(−18 ≤ VIN ≤ −8)
Dropout Voltage
Peak Output Current
Average Temperature
Coefficient of
TJ = 25˚C, IOUT = 1A
TJ = 25˚C
1.1
2.2
0.4
V
IOMAX
A
IOUT = 5mA,
mV/˚C
0 C ≤ TJ ≤ 100˚C
Output Voltage
Electrical Characteristics
Conditions unless otherwise noted: IOUT = 500mA, CIN = 2.2µF, COUT = 1µF, 0˚C ≤ TJ ≤ +125˚C, Power Dissipation ≤ 1.5W.
Part Number
Output Voltage
LM7912C
−12V
LM7915C
−15V
Units
Input Voltage (unless otherwise specified)
−19V
−23V
Symbol
Parameter
Output Voltage
Conditions
Min
Typ
Max
Min
Typ
Max
−15.6
−15.75
VO
TJ = 25˚C
−11.5 −12.0 −12.5
−14.4 −15.0
V
V
5mA ≤ IOUT ≤ 1A,
P ≤ 15W
−11.4
−12.6 −14.25
(−27 ≤ VIN ≤ −14.5)
(−30 ≤ VIN ≤ −17.5)
100
(−30 ≤ VIN≤ −17.5)
50
(−26 ≤ VIN ≤−20)
V
∆VO
Line Regulation
TJ = 25˚C, (Note 3)
5
80
(−30 ≤ VIN ≤ −14.5)
30
(−22 ≤ VIN ≤ −16)
5
mV
V
3
3
mV
V
∆VO
Load Regulation
TJ = 25˚C, (Note 3)
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2
Electrical Characteristics (Continued)
Conditions unless otherwise noted: IOUT = 500mA, CIN = 2.2µF, COUT = 1µF, 0˚C ≤ TJ ≤ +125˚C, Power Dissipation ≤ 1.5W.
Part Number
Output Voltage
LM7912C
−12V
−19V
Typ
LM7915C
−15V
−23V
Typ
Units
Input Voltage (unless otherwise specified)
Symbol
Parameter
Conditions
Min
Max
200
75
Min
Max
200
75
5mA ≤ IOUT ≤ 1.5A
250mA ≤ IOUT ≤ 750mA
TJ = 25˚C
15
15
mV
mV
mA
mA
V
5
5
IQ
Quiescent Current
Quiescent Current
Change
1.5
3
1.5
3
∆IQ
With Line
0.5
0.5
(−30 ≤ VIN ≤ −14.5)
(−30 ≤VIN ≤ −17.5)
With Load, 5mA ≤ IOUT ≤ 1A
TA = 25˚C, 10Hz ≤ f ≤ 100Hz
f = 120 Hz
0.5
0.5
mA
µV
dB
V
Vn
Output Noise Voltage
Ripple Rejection
300
375
54
70
54
70
(−25 ≤ VIN ≤ −15)
(−30 ≤ VIN≤ −17.5)
Dropout Voltage
Peak Output Current
Average Temperature
Coefficient of
TJ = 25˚C, IOUT = 1A
TJ = 25˚C
1.1
2.2
1.1
2.2
V
IOMAX
A
IOUT = 5mA,
−0.8
−1.0
mV/˚C
0 C ≤ TJ ≤ 100˚C
Output Voltage
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is
intended to be functional, but do not guarantee Specific Performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics.
Note 2: Refer to Typical Performance Characteristics and Design Considerations for details.
Note 3: Regulation is measured at a constant junction temperature by pulse testing with a low duty cycle. Changes in output voltage due to heating effects must
be taken into account.
Design Considerations
The LM79XX fixed voltage regulator series has thermal
overload protection from excessive power dissipation, inter-
nal short circuit protection which limits the circuit’s maximum
current, and output transistor safe-area compensation for
reducing the output current as the voltage across the pass
transistor is increased.
θJA = Junction-to-Ambient Thermal Resistance
θJC = Junction-to-Case Thermal Resistance
θCA = Case-to-Ambient Thermal Resistance
θCS = Case-to-Heat Sink Thermal Resistance
θSA = Heat Sink-to-Ambient Thermal Resistance
Although the internal power dissipation is limited, the junc-
tion temperature must be kept below the maximum specified
temperature (125˚C) in order to meet data sheet specifica-
tions. To calculate the maximum junction temperature or
heat sink required, the following thermal resistance values
should be used:
Typ
θJC
Max
θJC
Typ
θJA
Max
θJA
Package
˚C/W
3.0
˚C/W
5.0
˚C/W
60
˚C/W
40
TO-220
Solving for TJ:
TJ = TA + PD (θJC + θCA) or
= TA + PDθJA (without heat sink)
Where:
TJ
= Junction Temperature
TA = Ambient Temperature
PD = Power Dissipation
3
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Typical Applications
Bypass capacitors are necessary for stable operation of the
LM79XX series of regulators over the input voltage and
output current ranges. Output bypass capacitors will improve
the transient response by the regulator.
high frequency characteristics. If aluminum electrolytics are
used, their values should be 10µF or larger. The bypass
capacitors should be mounted with the shortest leads, and if
possible, directly across the regulator terminals.
The bypass capacitors, (2.2µF on the input, 1.0µF on the
output) should be ceramic or solid tantalum which have good
High Stability 1 Amp Regulator
DS007340-5
<
Load and line regulation 0.01% temperature stability ≤ 0.2%
†
Determine Zener current
††
Solid tantalum
*Select resistors to set output voltage. 2 ppm/˚C tracking suggested
Current Source
DS007340-7
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4
Typical Applications (Continued)
Light Controller Using Silicon Photo Cell
DS007340-8
*
†
Lamp brightness increase until i = i (≈ 1 mA) + 5V/R1.
Necessary only if raw supply filter capacitor is more that 2" from LM7905CT
I
Q
High-Sensitivity Light Controller
DS007340-9
*
†
Lamp brightness increases until i = 5V/R1 (I can be set as low as 1 µA)
Necessary only if raw supply filter capacitor is more that 2" from LM7905
i
i
Variable Output
DS007340-2
*Improves transient response and ripple rejection. Do not increase beyond 50 µF.
Select R2 as follows:
LM7905CT
LM7912CT
LM7915CT
300Ω
750Ω
1k
5
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Typical Applications (Continued)
±
15V, 1 Amp Tracking Regulators
DS007340-1
(-15)
(+15)
Load Regulation at ∆IL = 1A
Output Ripple, CIN = 3000µF, IL = 1A
Temperature Stability
40mV
2mV
100 µVms
50mV
100 µVms
50mV
Output Noise 10Hz ≤ f ≤ 10kHz
150 µVms
150 µVms
*Resistor tolerance of R4 and R5 determine matching of (+) and (−) outputs.
**Necessary only if raw supply filter capacitors are more than 3" from regulators.
Dual Trimmed Supply
DS007340-4
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6
Schematic Diagrams
7
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Schematic Diagrams (Continued)
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8
Physical Dimensions inches (millimeters) unless otherwise noted
TO-220 Outline Package (T)
Order Number LM7905CT, LM7912CT or LM7915CT
NS Package Number T03B
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can be reasonably expected to cause the failure of
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