LBRT 概述
20mA, 3V to 80V Low Dropout Micropower Linear Regulator 20mA时, 3V至80V低压差微功耗线性稳压器
LBRT 数据手册
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PDF下载LT3014
20mA, 3V to 80V
Low Dropout Micropower
Linear Regulator
U
FEATURES
DESCRIPTIO
The LT®3014 is a high voltage, micropower low dropout
linear regulator. The device is capable of supplying 20mA
of output current with a dropout voltage of 350mV. De-
signed for use in battery-powered or high voltage sys-
tems, the low quiescent current (7µA operating and 1µA in
shutdown) makes the LT3014 an ideal choice. Quiescent
current is also well controlled in dropout.
■
Wide Input Voltage Range: 3V to 80V
■
Low Quiescent Current: 7µA
■
Low Dropout Voltage: 350mV
Output Current: 20mA
■
■
LT3014HV Survives 100V Transients (2ms)
■
No Protection Diodes Needed
■
Adjustable Output from 1.22V to 60V
■
1µA Quiescent Current in Shutdown
Other features of the LT3014 include the ability to operate
with very small output capacitors. The regulators are
stable with only 0.47µF on the output while most older
devices require between 10µF and 100µF for stability.
Small ceramic capacitors can be used without the neces-
sary addition of ESR as is common with other regulators.
Internal protection circuitry includes reverse-battery pro-
tection, current limiting, thermal limiting and reverse
current protection.
■
Stable with 0.47µF Output Capacitor
■
Stable with Aluminum, Tantalum or Ceramic
Capacitors
Reverse-Battery Protection
■
■
No Reverse Current Flow from Output
■
Thermal Limiting
Available in 5-Lead ThinSOTTM and
■
8-Lead DFN Packages
U
APPLICATIO S
Thedeviceisavailableasanadjustabledevicewitha1.22V
reference voltage. The LT3014 regulator is available in the
5-lead ThinSOT and 8-lead DFN packages.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
ThinSOT is a trademark of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Protected by U.S. Patents including 6118263, 6144250.
■
Low Current High Voltage Regulators
■
Regulator for Battery-Powered Systems
■
Telecom Applications
Automotive Applications
■
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TYPICAL APPLICATIO
Dropout Voltage
400
350
300
250
200
150
100
50
5V Supply with Shutdown
V
OUT
IN
OUT
5V
20mA
V
IN
LT3014
3.92M
1.27M
5.4V TO
80V
0.47µF
1µF
SHDN
GND
ADJ
3014 TA01
V
OUTPUT
OFF
ON
SHDN
<0.3V
>2.0V
0
0
2
4
6
8
10 12 14 16 18 20
OUTPUT CURRENT (mA)
3014 TA02
3014fb
1
LT3014
W W U W
ABSOLUTE AXI U RATI GS (Note 1)
IN Pin Voltage, Operating ................................. ±80V
Transient (2ms Survival, LT3014HV).............. +100V
OUT Pin Voltage ............................................... ±60V
IN to OUT Differential Voltage........................... ±80V
ADJ Pin Voltage .................................................. ±7V
SHDN Pin Input Voltage ................................... ±80V
Output Short-Circuit Duration..................... Indefinite
Storage Temperature Range
ThinSOT Package......................... –65°C to 150°C
DFN Package ............................... –65°C to 125°C
Operating Junction Temperature Range
(Notes 3, 10, 11) ......................... –40°C to 125°C
Lead Temperature, SOT-23
(Soldering, 10 sec) ..................................... 300°C
U W
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PACKAGE/ORDER I FOR ATIO
TOP VIEW
TOP VIEW
OUT
ADJ
NC
1
2
3
4
8
7
6
5
IN
IN 1
GND 2
5 OUT
4 ADJ
NC
9
NC
SHDN 3
GND
SHDN
S5 PACKAGE
5-LEAD PLASTIC SOT-23
DD PACKAGE
8-LEAD (3mm × 3mm) PLASTIC DFN
EXPOSED PAD IS GND (PIN 9)
MUST BE SOLDERED TO PCB
TJMAX = 125°C, θJA = 40°C/ W
TJMAX = 125°C, θJA = 150°C/ W
JC = 25°C/ W MEASURED AT PIN 2.
SEE APPLICATIONS INFORMATION SECTION.
θ
θ
JC = 10°C/ W MEASURED AT PIN 9.
ORDER PART NUMBER
S5 PART MARKING
ORDER PART NUMBER
DD PART MARKING
LT3014ES5
LT3014HVES5
LTBMF
LTBRS
LT3014EDD
LT3014HVEDD
LBMG
LBRT
Order Options Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking: http://www.linear.com/leadfree/
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS
The
●
denotes specifications which apply over the full operating temperature range, otherwise specifications are at T = 25°C.
J
PARAMETER
CONDITIONS
= 20mA
MIN
TYP
MAX
UNITS
Minimum Input Voltage
I
●
3
3.3
V
LOAD
ADJ Pin Voltage
(Notes 2, 3)
V
= 3.3V, I
= 100µA
LOAD
1.200
1.180
1.220
1.220
1.240
1.260
V
V
IN
3.3V < V < 80V, 100µA < I
< 20mA
●
●
IN
LOAD
Line Regulation
Load Regulation
∆V = 3.3V to 80V, I
= 100µA (Note 2)
LOAD
1
10
mV
IN
V
V
= 3.3V, ∆I
= 3.3V, ∆I
= 100µA to 20mA (Note 2)
= 100µA to 20mA
13
25
40
mV
mV
IN
IN
LOAD
LOAD
●
3014fb
2
LT3014
ELECTRICAL CHARACTERISTICS
The
●
denotes specifications which apply over the full operating temperature range, otherwise specifications are at T = 25°C.
J
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Dropout Voltage
I
I
= 100µA
= 100µA
120
180
250
mV
mV
LOAD
LOAD
V
= V
(Notes 4, 5)
●
●
●
●
IN
OUT(NOMINAL)
I
I
= 1mA
= 1mA
200
300
350
270
360
mV
mV
LOAD
LOAD
I
I
= 10mA
= 10mA
350
450
mV
mV
LOAD
LOAD
I
I
= 20mA
= 20mA
410
570
mV
mV
LOAD
LOAD
GND Pin Current
= V
(Notes 4, 6)
I
I
I
I
I
= 0mA
= 100µA
= 1mA
= 10mA
= 20mA
●
●
●
●
●
7
12
40
250
650
20
30
100
450
1000
µA
µA
µA
µA
µA
LOAD
LOAD
LOAD
LOAD
LOAD
V
IN
OUT(NOMINAL)
Output Voltage Noise
ADJ Pin Bias Current
Shutdown Threshold
C
= 0.47µF, I
= 20mA, BW = 10Hz to 100kHz
115
4
µV
RMS
OUT
LOAD
(Note 7)
10
2
nA
V
V
= Off to On
= On to Off
●
●
1.3
1.3
V
V
OUT
OUT
0.25
SHDN Pin Current
(Note 8)
V
V
= 0V
= 6V
●
●
1
0
4
1
µA
µA
SHDN
SHDN
Quiescent Current in Shutdown
Ripple Rejection
V
V
= 6V, V
= 0V
●
1
4
µA
IN
IN
SHDN
= 7V(Avg), V
= 0.5V , f
= 120Hz, I = 20mA
LOAD
60
25
70
70
dB
RIPPLE
P-P RIPPLE
Current Limit
V
V
= 7V, V
= 0V
mA
mA
IN
IN
OUT
= 3.3V, ∆V
= –0.1V (Note 2)
●
●
OUT
Input Reverse
Leakage Current
V
= –80V, V
= 0V
OUT
6
4
mA
IN
Reverse Output Current
(Note 9)
V
= 1.22V, V < 1.22V (Note 2)
2
µA
OUT
IN
Note 6: GND pin current is tested with V = V
(nominal) and a current
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
IN
OUT
source load. This means the device is tested while operating in its dropout
region. This is the worst-case GND pin current. The GND pin current
decreases slightly at higher input voltages.
Note 7: ADJ pin bias current flows into the ADJ pin.
Note 8: SHDN pin current flows out of the SHDN pin.
Note 2: The LT3014 is tested and specified for these conditions with the
ADJ pin connected to the OUT pin.
Note 3: Operating conditions are limited by maximum junction
temperature. The regulated output voltage specification will not apply for
all possible combinations of input voltage and output current. When
operating at maximum input voltage, the output current range must be
limited. When operating at maximum output current, the input voltage
range must be limited.
Note 4: To satisfy requirements for minimum input voltage, the LT3014 is
tested and specified for these conditions with an external resistor divider
(249k bottom, 392k top) for an output voltage of 3.3V. The external
resistor divider adds a 5µA DC load on the output.
Note 9: Reverse output current is tested with the IN pin grounded and the
OUT pin forced to the rated output voltage. This current flows into the OUT
pin and out of the GND pin.
Note 10: The LT3014E is guaranteed to meet performance specifications
from 0°C to 125°C operating junction temperature. Specifications over
the –40°C to 125°C operating junction temperature range are assured by
design, characterization and correlation with statistical process controls.
Note 11: This IC includes overtemperature protection that is intended to
protect the device during momentary overload conditions. Junction
temperature will exceed 125°C when overtemperature protection is
active. Continuous operation above the specified maximum operating
junction temperature may impair device reliability.
Note 5: Dropout voltage is the minimum input to output voltage differential
needed to maintain regulation at a specified output current. In dropout, the
output voltage is equal to (V – V
).
IN
DROPOUT
3014fb
3
LT3014
TYPICAL PERFOR A CE CHARACTERISTICS
U W
Typical Dropout Voltage
Guaranteed Dropout Voltage
Dropout Voltage
600
500
500
450
400
350
300
250
200
150
100
50
500
450
400
350
300
250
200
150
100
50
= TEST POINTS
T
J
≤ 125°C
T
J
= 125°C
I
L
= 20mA
400
300
T
≤ 25°C
I
L
= 10mA
J
T
J
= 25°C
I
L
= 1mA
200
100
0
I
L
= 100µA
0
0
0
2
4
6
8
10 12 14 16 18 20
0
2
4
6
8
10 12 14 16 18 20
–50
0
25
50
75 100 125
–25
OUTPUT CURRENT (mA)
TEMPERATURE (°C)
OUTPUT CURRENT (mA)
3014 G01
3014 G02
3014 G03
Quiescent Current
ADJ Pin Voltage
Quiescent Current
1.240
16
16
14
12
10
8
I
= 100µA
T
R
V
= 25°C
= ∞
OUT
V
= 6V
L
J
L
IN
L
R
I
= ∞
1.235
1.230
14
12
= 1.22V
= 0
L
1.225
1.220
1.215
1.210
1.205
10
8
V
= V
IN
SHDN
V
= V
IN
SHDN
6
6
4
4
2
2
V
= 0V
SHDN
V
= 0V
5
SHDN
4
0
1.200
0
–25
0
50
75 100 125
1
2
3
6
7
9
–50
25
0
8
10
–25
0
50
75 100 125
–50
25
TEMPERATURE (°C)
INPUT VOLTAGE (V)
TEMPERATURE (°C)
3014 G05
3014 G06
3014 G04
GND Pin Current
GND Pin Current vs I
SHDN Pin Threshold
LOAD
1000
900
800
700
600
500
400
300
200
100
0
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
1000
900
800
700
600
500
400
300
200
100
0
T
= 25°C
V
T
= 3.3V
J
IN
J
*FOR V
= 1.22V
= 25°C
OUT
V
= 1.22V
OUT
R
L
= 61Ω
L
I
= 20mA*
R
I
= 122Ω
L
L
= 10mA*
R
L
= 1.22k
= 1mA*
L
I
0
1
2
3
4
5
6
7
8
9
10
–50 –25
0
25
50
75 100 125
0
2
4
6
8
10 12 14 16 18 20
INPUT VOLTAGE (V)
TEMPERATURE (°C)
OUTPUT CURRENT (mA)
3014 G09
3014 G07
3014 G08
3014fb
4
LT3014
U W
TYPICAL PERFOR A CE CHARACTERISTICS
SHDN Pin Current
SHDN Pin Current
ADJ Pin Bias Current
14
12
10
8
1.2
1.0
1.6
T
= 25°C
V
SHDN
= 0V
J
CURRENT FLOWS
OUT OF SHDN PIN
CURRENT FLOWS
OUT OF SHDN PIN
1.4
1.2
0.8
0.6
1.0
0.8
0.6
0.4
0.2
6
0.4
0.2
0
4
2
0
–50
0
–25
0
50
75 100 125
25
2.5
3
–25
0
50
75 100 125
0
0.5
1
1.5
2
3.5
4
–50
25
SHDN PIN VOLTAGE (V)
TEMPERATURE (°C)
TEMPERATURE (°C)
3014 G12
3014 G10
3014 G11
Current Limit
Current Limit
Reverse Output Current
50
45
40
35
30
25
20
15
10
5
100
90
80
70
60
50
40
30
20
10
0
80
V
V
= 7V
V
T
= 0V
T
= 25°C
J
IN
OUT
OUT
J
= 0V
= 25°C
V
= 0V
IN
OUT
70
60
ADJ PIN
ESD CLAMP
V
= V
ADJ
50
40
30
20
10
CURRENT FLOWS
INTO OUTPUT PIN
0
0
0
1
2
3
4
5
6
7
8
9
10
0
2
4
6
8
10 12 14 16 18 20
–50
0
25
50
75 100 125
–25
TEMPERATURE (°C)
OUTPUT VOLTAGE (V)
INPUT VOLTAGE (V)
3014 G15
3014 G13
3014 G14
Reverse Output Current
Input Ripple Rejection
Input Ripple Rejection
72
8
80
V
V
= 0V
= V
V
= 7V + 0.5V
P-P
V
I
= 7V + 50mV
RIPPLE
IN
OUT
IN
IN
RMS
= 1.22V
ADJ
RIPPLE AT f = 120Hz
= 20mA
L
70
68
7
6
70
60
I
= 20mA
L
66
64
62
60
58
5
4
3
2
1
50
40
30
20
10
C
= 4.7µF
OUT
C
= 0.47µF
OUT
56
0
0
–25
0
50
75 100 125
–50
25
–25
0
50
75 100 125
10
100
1k
10k
100k
1M
–50
25
TEMPERATURE (°C)
TEMPERATURE (°C)
FREQUENCY (Hz)
3014 G18
3014 G17
3014 G16
3014fb
5
LT3014
TYPICAL PERFOR A CE CHARACTERISTICS
U W
Minimum Input Voltage
Load Regulation
Output Noise Spectral Density
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
10
1
0
I
= 20mA
∆I = 100µA TO 20mA
C
L
V
= 0.47µF
LOAD
L
OUT
OUT
OUT
V
= 1.22V
I
= 20mA
–5
= 1.22V
–10
–15
–20
–25
–30
–35
0.1
0.01
–40
–50 –25
0
25
50
75
100 125
–50 –25
0
25
50
75 100 125
10
100
1k
10k
100k
TEMPERATURE (°C)
TEMPERATURE (°C)
FREQUENCY (Hz)
3014 G21
3014 G19
3014 G20
10Hz to 100kHz Output Noise
Transient Response
0.04
0.02
0
V
= 7V
= 5V
VOUT
200µV/DIV
IN
–0.02
–0.04
V
OUT
C
= C
= 0.47µF CERAMIC
IN
OUT
∆I
= 1mA TO 5mA
LOAD
6
4
COUT = 0.47µF
1ms/DIV
3014 G22
2
0
IL = 20mA
V
OUT = 1.22V
0
200
400
600
800
1000
TIME (µs)
3014 G23
U
U
U
PI FU CTIO S (SOT-23 Package/DD Package)
appear at the load. The device will protect both itself and
the load.
IN (Pin 1/Pin 8): Input. Power is supplied to the device
through the IN pin. A bypass capacitor is required on this
pinifthedeviceismorethansixinchesawayfromthemain
input filter capacitor. In general, the output impedance of
a battery rises with frequency, so it is advisable to include
a bypass capacitor in battery-powered circuits. A bypass
capacitor in the range of 0.1µF to 10µF is sufficient. The
LT3014 is designed to withstand reverse voltages on the
IN pin with respect to ground and the OUT pin. In the case
of a reversed input, which can happen if a battery is
plugged in backwards, the LT3014 will act as if there is a
diode in series with its input. There will be no reverse
current flow into the LT3014 and no reverse voltage will
GND (Pin 2/Pins 4, 9): Ground.
SHDN (Pin 3/Pin 5): Shutdown. The SHDN pin is used to
put the LT3014 into a low power shutdown state. The
output will be off when the SHDN pin is pulled low. The
SHDN pin can be driven either by 5V logic or open-
collector logic with a pull-up resistor. The pull-up resistor
is only required to supply the pull-up current of the open-
collector gate, normally several microamperes. If unused,
the SHDN pin must be tied to IN or to a logic high.
3014fb
6
LT3014
U
U
U
PI FU CTIO S (SOT-23 Package/DD Package)
OUT (Pin 5/Pin 1): Output. The output supplies power to
the load. A minimum output capacitor of 0.47µF is re-
quired to prevent oscillations. Larger output capacitors
will be required for applications with large transient loads
to limit peak voltage transients. See the Applications
Information section for more information on output ca-
pacitance and reverse output characteristics.
ADJ (Pin 4/Pin 2): Adjust. This is the input to the error
amplifier. This pin is internally clamped to ±7V. It has a
bias current of 4nA which flows into the pin (see curve of
ADJPinBiasCurrentvsTemperatureintheTypicalPerfor-
mance Characteristics). The ADJ pin voltage is 1.22V
referenced to ground, and the output voltage range is
1.22V to 60V.
W U U
U
APPLICATIO S I FOR ATIO
than 1.22V will be proportional to the ratio of the desired
output voltage to 1.22V (VOUT/1.22V). For example, load
regulation for an output current change of 1mA to 20mA
is –13mV typical at VOUT = 1.22V. At VOUT = 12V, load
regulation is:
The LT3014 is a 20mA high voltage low dropout regulator
with micropower quiescent current and shutdown. The
device is capable of supplying 20mA at a dropout voltage
of 350mV. The low operating quiescent current (7µA)
drops to 1µA in shutdown. In addition to the low quiescent
current, the LT3014 incorporates several protection fea-
tures which make it ideal for use in battery-powered
systems. The device is protected against both reverse
input and reverse output voltages. In battery backup
applications where the output can be held up by a backup
batterywhentheinputispulledtoground,theLT3014acts
like it has a diode in series with its output and prevents
reverse current flow.
(12V/1.22V) • (–13mV) = –128mV
V
IN
OUT
LT3014
ADJ
OUT
+
R2
R1
V
IN
GND
3014 F01
R2
R1
V
V
= 1.22V 1 +
•
+ (I )(R2)
ADJ
OUT
ADJ
(
)
= 1.22V
= 4nA AT 25°C
I
ADJ
Adjustable Operation
OUTPUT RANGE = 1.22V TO 60V
The LT3014 has an output voltage range of 1.22V to 60V.
The output voltage is set by the ratio of two external
resistors as shown in Figure 2. The device servos the
output to maintain the voltage at the adjust pin at 1.22V
referenced to ground. The current in R1 is then equal to
Figure 1. Adjustable Operation
Output Capacitance and Transient Response
The LT3014 is designed to be stable with a wide range of
1.22V/R1 and the current in R2 is the current in R1 plus output capacitors. The ESR of the output capacitor affects
stability, most notably with small capacitors. A minimum
output capacitor of 0.47µF with an ESR of 3Ω or less is
the ADJ pin bias current. The ADJ pin bias current, 4nA
at 25°C, flows through R2 into the ADJ pin. The output
voltage can be calculated using the formula in Figure 1. recommended to prevent oscillations. The LT3014 is a
micropower device and output transient response will be
a function of output capacitance. Larger values of output
The value of R1 should be less than 1.62M to minimize
errors in the output voltage caused by the ADJ pin bias
current. Note that in shutdown the output is turned off capacitance decrease the peak deviations and provide
improved transient response for larger load current
changes. Bypass capacitors, used to decouple individual
components powered by the LT3014, will increase the
effective output capacitor value.
and the divider current will be zero. The device is tested
and specified with the ADJ pin tied to the OUT pin and a
5µA DC load (unless otherwise specified) for an output
voltageof1.22V.Specificationsforoutputvoltagesgreater
3014fb
7
LT3014
W U U
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APPLICATIO S I FOR ATIO
Extra consideration must be given to the use of ceramic
capacitors. Ceramic capacitors are manufactured with a
variety of dielectrics, each with different behavior across
temperature and applied voltage. The most common di-
electrics used are Z5U, Y5V, X5R and X7R. The Z5U and
Y5V dielectrics are good for providing high capacitances
in a small package, but exhibit strong voltage and tem-
perature coefficients as shown in Figures 2 and 3. When
used with a 5V regulator, a 10µF Y5V capacitor can exhibit
an effective value as low as 1µF to 2µF over the operating
temperature range. The X5R and X7R dielectrics result in
more stable characteristics and are more suitable for use
as the output capacitor. The X7R type has better stability
across temperature, while the X5R is less expensive and
is available in higher values.
similar to the way a piezoelectric accelerometer or micro-
phone works. For a ceramic capacitor the stress can be
induced by vibrations in the system or thermal transients.
Thermal Considerations
The power handling capability of the device will be limited
by the maximum rated junction temperature (125°C). The
power dissipated by the device will be made up of two
components:
1. Output current multiplied by the input/output voltage
differential: IOUT • (VIN – VOUT) and,
2. GND pin current multiplied by the input voltage:
IGND • VIN.
The GND pin current can be found by examining the GND
Pin Current curves in the Typical Performance Character-
istics.Powerdissipationwillbeequaltothesumofthetwo
components listed above.
Voltage and temperature coefficients are not the only
sources of problems. Some ceramic capacitors have a
piezoelectric response. A piezoelectric device generates
voltage across its terminals due to mechanical stress,
40
20
20
BOTH CAPACITORS ARE 16V,
1210 CASE SIZE, 10µF
0
X5R
0
–20
X5R
–20
–40
–40
Y5V
–60
–60
Y5V
–80
–80
BOTH CAPACITORS ARE 16V,
1210 CASE SIZE, 10µF
–100
–100
50
TEMPERATURE (°C)
100 125
–50 –25
0
25
75
0
8
12 14
2
4
6
10
16
DC BIAS VOLTAGE (V)
3014 F03
3014 F02
Figure 2. Ceramic Capacitor DC Bias Characteristics
Figure 3. Ceramic Capacitor Temperature Characteristics
3014fb
8
LT3014
W U U
APPLICATIO S I FOR ATIO
U
Continuous operation at large input/output voltage differ-
entials and maximum load current is not practical due to
thermal limitations. Transient operation at high input/
output differentials is possible. The approximate thermal
time constant for a 2500sq mm 3/32" FR-4 board with
maximumtopsideandbacksideareaforoneouncecopper
is 3 seconds. This time constant will increase as more
thermal mass is added (i.e. vias, larger board, and other
components).
The LT3014 regulator has internal thermal limiting de-
signed to protect the device during overload conditions.
For continuous normal conditions the maximum junction
temperature rating of 125°C must not be exceeded. It is
important to give careful consideration to all sources of
thermal resistance from junction to ambient. Additional
heat sources mounted nearby must also be considered.
For surface mount devices, heat sinking is accomplished
by using the heat spreading capabilities of the PC board
and its copper traces. Copper board stiffeners and plated
through-holes can also be used to spread the heat gener-
ated by power devices.
For an application with transient high power peaks, aver-
age power dissipation can be used for junction tempera-
turecalculationsaslongasthepulseperiodissignificantly
less than the thermal time constant of the device and
board.
The following table lists thermal resistance for several
different board sizes and copper areas. All measurements
were taken in still air on 3/32" FR-4 board with one ounce
copper.
Calculating Junction Temperature
Example 1: Given an output voltage of 5V, an input voltage
range of 24V to 30V, an output current range of 0mA to
20mA, and a maximum ambient temperature of 50°C,
what will the maximum junction temperature be?
Table 1. SOT-23 Measured Thermal Resistance
COPPER AREA
THERMAL RESISTANCE
TOPSIDE
2500 sq mm
1000 sq mm
225 sq mm
100 sq mm
50 sq mm
BACKSIDE
2500 sq mm
2500 sq mm
2500 sq mm
2500 sq mm
2500 sq mm
BOARD AREA
2500 sq mm
2500 sq mm
2500 sq mm
2500 sq mm
2500 sq mm
(JUNCTION-TO-AMBIENT)
125°C/W
The power dissipated by the device will be equal to:
125°C/W
130°C/W
I
OUT(MAX) • (VIN(MAX) – VOUT) + (IGND • VIN(MAX)
where:
IOUT(MAX) = 20mA
)
135°C/W
150°C/W
Table 2. DFN Measured Thermal Resistance
VIN(MAX) = 30V
COPPER AREA
THERMAL RESISTANCE
IGND at (IOUT = 20mA, VIN = 30V) = 0.55mA
TOPSIDE
2500 sq mm
1000 sq mm
225 sq mm
100 sq mm
BACKSIDE
2500 sq mm
2500 sq mm
2500 sq mm
2500 sq mm
BOARD AREA
2500 sq mm
2500 sq mm
2500 sq mm
2500 sq mm
(JUNCTION-TO-AMBIENT)
40°C/W
So:
45°C/W
P = 20mA • (30V – 5V) + (0.55mA • 30V) = 0.52W
50°C/W
The thermal resistance for the DFN package will be in the
rangeof40°C/Wto62°C/Wdependingonthecopperarea.
So the junction temperature rise above ambient will be
approximately equal to:
62°C/W
For the DFN package, the thermal resistance junction-to-
case(θJC),measuredattheexposedpadonthebackofthe
die, is 16°C/W.
0.52W • 50°C/W = 26°C
3014fb
9
LT3014
W U U
U
APPLICATIO S I FOR ATIO
The maximum junction temperature will then be equal to
the maximum junction temperature rise above ambient
plus the maximum ambient temperature or:
Protection Features
TheLT3014incorporatesseveralprotectionfeatureswhich
make it ideal for use in battery-powered circuits. In addi-
tion to the normal protection features associated with
monolithic regulators, such as current limiting and ther-
mal limiting, the device is protected against reverse-input
voltages, and reverse voltages from output to input.
T
JMAX = 50°C + 26°C = 76°C
Example 2: Given an output voltage of 5V, an input voltage
of 48V that rises to 72V for 5ms(max) out of every 100ms,
and a 5mA load that steps to 20mA for 50ms out of every
250ms, what is the junction temperature rise above ambi-
ent? Using a 500ms period (well under the time constant
of the board), power dissipation is as follows:
Current limit protection and thermal overload protection
areintendedtoprotectthedeviceagainstcurrentoverload
conditions at the output of the device. For normal opera-
tion, the junction temperature should not exceed 125°C.
P1(48V in, 5mA load) = 5mA • (48V – 5V)
+ (100µA • 48V) = 0.22W
The input of the device will withstand reverse voltages of
80V.Currentflowintothedevicewillbelimitedtolessthan
6mA (typically less than 100µA) and no negative voltage
will appear at the output. The device will protect both itself
and the load. This provides protection against batteries
which can be plugged in backward.
P2(48V in, 20mA load) = 20mA • (48V – 5V)
+ (0.55mA • 48V) = 0.89W
P3(72V in, 5mA load) = 5mA • (72V – 5V)
+ (100µA • 72V) = 0.34W
P4(72V in, 20mA load) = 20mA • (72V – 5V)
+ (0.55mA • 72V) = 1.38W
The ADJ pin can be pulled above or below ground by as
muchas7Vwithoutdamagingthedevice.Iftheinputisleft
open circuit or grounded, the ADJ pin will act like an open
circuit when pulled below ground, and like a large resistor
(typically 100k) in series with a diode when pulled above
ground. Iftheinputispoweredbyavoltagesource, pulling
the ADJ pin below the reference voltage will cause the
device to current limit. This will cause the output to go to
an unregulated high voltage. Pulling the ADJ pin above the
reference voltage will turn off all output current.
Operation at the different power levels is as follows:
76% operation at P1, 19% for P2, 4% for P3, and
1% for P4.
P
EFF = 76%(0.22W) + 19%(0.89W) + 4%(0.34W)
+ 1%(1.38W) = 0.36W
With a thermal resistance in the range of 40°C/W to
62°C/W, this translates to a junction temperature rise
above ambient of 20°C.
3014fb
10
LT3014
W U U
APPLICATIO S I FOR ATIO
U
In situations where the ADJ pin is connected to a resistor
divider that would pull the ADJ pin above its 7V clamp
voltage if the output is pulled high, the ADJ pin input
current must be limited to less than 5mA. For example, a
resistor divider is used to provide a regulated 1.5V output
fromthe1.22Vreferencewhentheoutputisforcedto60V.
The top resistor of the resistor divider must be chosen to
limitthecurrentintotheADJpintolessthan5mAwhenthe
ADJ pin is at 7V. The 53V difference between the OUT and
ADJ pins divided by the 5mA maximum current into the
ADJ pin yields a minimum top resistor value of 10.6k.
open circuit. Current flow back into the output will follow
the curve shown in Figure 4. The rise in reverse output
current above 7V occurs from the breakdown of the 7V
clamp on the ADJ pin. With a resistor divider on the
regulator output, this current will be reduced depending
on the size of the resistor divider.
When the IN pin of the LT3014 is forced below the OUT pin
or the OUT pin is pulled above the IN pin, input current will
typicallydroptolessthan2µA. Thiscanhappeniftheinput
of the LT3014 is connected to a discharged (low voltage)
battery and the output is held up by either a backup battery
orasecondregulatorcircuit.ThestateoftheSHDNpinwill
have no effect on the reverse output current when the
output is pulled above the input.
In circuits where a backup battery is required, several
different input/output conditions can occur. The output
voltage may be held up while the input is either pulled to
ground, pulled to some intermediate voltage, or is left
50
T
V
V
= 25°C
J
45
40
35
30
25
20
15
10
5
= 0V
IN
OUT
ADJ PIN
ESD CLAMP
= V
ADJ
CURRENT FLOWS
INTO OUTPUT PIN
0
0
1
2
3
4
5
6
7
8
9
10
OUTPUT VOLTAGE (V)
3014 F04
Figure 4. Reverse Output Current
3014fb
11
LT3014
TYPICAL APPLICATIO S
U
5V Buck Converter with Low Current Keep Alive Backup
D2
D1N914
6
C2
L1†
15µH
0.33µF
BOOST
V
V
IN
OUT
4
2
5.5V*
V
SW
5V
IN
C3
4.7µF
100V
D1
TO 60V
1A/20mA
10MQ060N
LT1766
CERAMIC
15
14
10
12
SHDN
BIAS
FB
R1
C1
+
15.4k
100µF 10V
SOLID
SYNC
GND
R2
4.99k
TANTALUM
V
C
1, 8, 9, 16 11
C
C
1nF
3014 TA03
IN
OUT
*FOR INPUT VOLTAGES BELOW 7.5V,
SOME RESTRICTIONS MAY APPLY
† INCREASE L1 TO 30µH FOR LOAD
CURRENTS ABOVE 0.6A AND TO
60µH ABOVE 1A
LT3014
3.92M
1.27M
OPERATING
CURRENT
SHDN
ADJ
HIGH
LOW
GND
Buck Converter
Efficiency vs Load Current
100
V
= 5V
OUT
L = 68µH
V
V
= 10V
= 42V
IN
IN
90
80
70
60
50
0
0.25
0.50
0.75
1.00
1.25
LOAD CURRENT (A)
3014 TA04
3014fb
12
LT3014
U
TYPICAL APPLICATIO S
LT3014 Automotive Application
IN
OUT
ADJ
NO PROTECTION
DIODE NEEDED!
+
V
IN
LT3014
SHDN
R1
R2
1µF
12V
1µF
LOAD: CLOCK,
SECURITY SYSTEM
ETC
(LATER 42V)
GND
OFF
ON
LT3014 Telecom Application
V
IN
48V
(72V TRANSIENT)
IN
OUT
+
–
LT3014
BACKUP
BATTERY
R1
R2
NO PROTECTION
DIODE NEEDED!
1µF
1µF
LOAD:
SYSTEM MONITOR
ETC
SHDN
ADJ
GND
3014 TA05
OFF
ON
Constant Brightness for Indicator LED over Wide Input Voltage Range
RETURN
IN
OUT
LT3014
1µF
1µF
OFF ON
–48V
SHDN ADJ
GND
R
SET
3014 TA06
I
= 1.22V/R
SET
LED
–48V CAN VARY FROM –3.3V TO –80V
3014fb
13
LT3014
U
PACKAGE DESCRIPTIO
S5 Package
5-Lead Plastic TSOT-23
(Reference LTC DWG # 05-08-1635)
0.62
MAX
0.95
REF
2.90 BSC
(NOTE 4)
1.22 REF
1.50 – 1.75
(NOTE 4)
2.80 BSC
1.4 MIN
3.85 MAX 2.62 REF
PIN ONE
RECOMMENDED SOLDER PAD LAYOUT
PER IPC CALCULATOR
0.30 – 0.45 TYP
5 PLCS (NOTE 3)
0.95 BSC
0.80 – 0.90
0.20 BSC
DATUM ‘A’
0.01 – 0.10
1.00 MAX
0.30 – 0.50 REF
1.90 BSC
0.09 – 0.20
(NOTE 3)
NOTE:
S5 TSOT-23 0302 REV B
1. DIMENSIONS ARE IN MILLIMETERS
2. DRAWING NOT TO SCALE
3. DIMENSIONS ARE INCLUSIVE OF PLATING
4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR
5. MOLD FLASH SHALL NOT EXCEED 0.254mm
6. JEDEC PACKAGE REFERENCE IS MO-193
3014fb
14
LT3014
U
PACKAGE DESCRIPTIO
DD Package
8-Lead Plastic DFN (3mm × 3mm)
(Reference LTC DWG # 05-08-1698)
0.675 ±0.05
3.5 ±0.05
2.15 ±0.05 (2 SIDES)
1.65 ±0.05
PACKAGE
OUTLINE
0.25 ± 0.05
0.50
BSC
2.38 ±0.05
(2 SIDES)
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
R = 0.115
0.38 ± 0.10
TYP
5
8
3.00 ±0.10
(4 SIDES)
1.65 ± 0.10
(2 SIDES)
PIN 1
TOP MARK
(NOTE 6)
(DD) DFN 1203
4
1
0.25 ± 0.05
0.75 ±0.05
0.200 REF
0.50 BSC
2.38 ±0.10
(2 SIDES)
0.00 – 0.05
BOTTOM VIEW—EXPOSED PAD
NOTE:
1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WEED-1)
2. DRAWING NOT TO SCALE
3. ALL DIMENSIONS ARE IN MILLIMETERS
4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE
5. EXPOSED PAD SHALL BE SOLDER PLATED
6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION
ON TOP AND BOTTOM OF PACKAGE
3014fb
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tationthattheinterconnectionofitscircuitsasdescribedhereinwillnotinfringeonexistingpatentrights.
15
LT3014
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
V : 4.2V to 30V, V
LT1129
700mA, Micropower, LDO
= 3.75V, V = 0.4V, I = 50µA, I = 16µA,
OUT(MIN) DO Q SD
IN
DD, SOT-223, S8, TO220, TSSOP-20 Packages
LT1175
LT1185
LT1761
LT1762
LT1763
500mA, Micropower Negative LDO
3A, Negative LDO
V : –20V to –4.3V, V = –3.8V, V = 0.50V, I = 45µA, I = 10µA,
IN
OUT(MIN)
DO
Q
SD
DD, SOT-223, S8 Packages
V : –35V to –4.2V, V
TO220-5 Package
= –2.40V, V = 0.80V, I = 2.5mA, I <1µA,
DO Q SD
IN
OUT(MIN)
100mA, Low Noise Micropower, LDO
150mA, Low Noise Micropower, LDO
500mA, Low Noise Micropower, LDO
V : 1.8V to 20V, V
ThinSOT Package
= 1.22V, V = 0.30V, I = 20µA, I <1µA,
DO Q SD
IN
OUT(MIN)
OUT(MIN)
OUT(MIN)
OUT(MIN)
V : 1.8V to 20V, V
= 1.22V, V = 0.30V, I = 25µA, I <1µA,
DO Q SD
IN
MS8 Package
V : 1.8V to 20V, V
= 1.22V, V = 0.30V, I = 30µA, I <1µA,
DO Q SD
IN
S8 Package
LT1764/LT1764A 3A, Low Noise, Fast Transient Response, LDO
V : 2.7V to 20V, V
= 1.21V, V = 0.34V, I = 1mA, I <1µA,
DO Q SD
IN
DD, TO220 Packages
LTC1844
LT1962
150mA, Very Low Dropout LDO
V : 1.6V to 6.5V, V
ThinSOT Package
= 1.25V, V = 0.08V, I = 40µA, I <1µA,
DO Q SD
IN
OUT(MIN)
OUT(MIN)
OUT(MIN)
300mA, Low Noise Micropower, LDO
V : 1.8V to 20V, V
= 1.22V, V = 0.27V, I = 30µA, I <1µA,
DO Q SD
IN
MS8 Package
LT1963/LT1963A 1.5A, Low Noise, Fast Transient Response, LDO V : 2.1V to 20V, V
= 1.21V, V = 0.34V, I = 1mA, I <1µA,
DO Q SD
IN
DD, TO220, SOT Packages
LT1964
LT3010
LT3020
LT3023
LT3024
LT3027
LT3028
200mA, Low Noise Micropower, Negative LDO
50mA, 80V, Low Noise Micropower, LDO
V : –1.9V to –20V, V
ThinSOT Package
= –1.21V, V = 0.34V, I = 30µA, I = 3µA,
OUT(MIN) DO Q SD
IN
V : 3V to 80V, V
IN
= 1.28V, V = 0.3V, I = 30µA, I <1µA,
DO Q SD
OUT(MIN)
MS8E Package
100mA, Low V , Low V
Micropower, VLDO V : 0.9V to 10V, V
= 0.20V, V = 0.15V, I = 120µA, I <1µA,
OUT(MIN) DO Q SD
IN
OUT
IN
DFN, MS8 Packages
Dual 100mA, Low Noise Micropower, LDO
V : 1.8V to 20V, V
IN
= 1.22V, V = 0.30V, I = 40µA, I <1µA,
DO Q SD
OUT(MIN)
DFN, MS10 Packages
Dual 100mA/500mA, Low Noise Micropower,
LDO
V : 1.8V to 20V, V
IN
= 1.22V, V = 0.30V, I = 60µA, I <1µA,
DO Q SD
OUT(MIN)
DFN, TSSOP-16E Packages
Dual 100mA, Low Noise LDO with Independent V : 1.8V to 20V, V
Inputs
= 1.22V, V = 0.30V, I = 40µA, I <1µA,
DO Q SD
IN
OUT(MIN)
DFN, MS10E Packages
Dual 100mA/500mA, Low Noise LDO with
Independent Inputs
V : 1.8V to 20V, V
IN
= 1.22V, V = 0.30V, I = 60µA, I <1µA,
DO Q SD
OUT(MIN)
DFN, TSSOP-16E Packages
3014fb
LT/LWI 0706 REV B • PRINTED IN USA
LinearTechnology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
16
●
●
(408) 432-1900 FAX: (408) 434-0507 www.linear.com
© LINEAR TECHNOLOGY CORPORATION 2005
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