Page 1
FEATURES
■
Wide Input Voltage Range: 3V to 80V
■
Low Quiescent Current: 30µA
■
Low Dropout Voltage: 300mV
■
Output Current: 50mA
■
Thermally Enhanced 8-Lead MSOP Package
■
No Protection Diodes Needed
■
Fixed Output Voltage: 5V (LT3010-5)
■
Adjustable Output from 1.275V to 60V (LT3010)
■
1µA Quiescent Current in Shutdown
■
Stable with 1µF Output Capacitor
■
Stable with Aluminum, Tantalum or Ceramic
Capacitors
■
Reverse-Battery Protection
■
No Reverse Current Flow from Output
■
Thermal Limiting
U
APPLICATIO S
■
Low Current High Voltage Regulators
■
Regulator for Battery-Powered Systems
■
Telecom Applications
■
Automotive Applications
LT3010/LT3010-5
50mA, 3V to 80V
Low Dropout
Micropower Linear Regulator
U
DESCRIPTIO
The LT®3010 is a high voltage, micropower low dropout
linear regulator. The device is capable of supplying 50mA
output current with a dropout voltage of 300mV. Designed
for use in battery-powered or high voltage systems, the
low quiescent current (30µA operating and 1µA in shut-
down) makes the LT3010 an ideal choice. Quiescent
current is also well controlled in dropout.
Other features of the LT3010 include the ability to operate
with very small output capacitors. The regulators are
stable with only 1µF on the output while most older
devices require between 10µF and 100µF for stability.
Small ceramic capacitors can be used without the necessary addition of ESR as is common with other regulators.
Internal protection circuitry includes reverse-battery protection, current limiting, thermal limiting and reverse
current protection.
The device is available in a fixed output voltage of 5V and
as an adjustable device with a 1.275V reference voltage.
The LT3010 regulator is available in the 8-lead MSOP
package with an exposed pad for enhanced thermal handling capability.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATIO
5V Supply with Shutdown
1µF
OFF
ON
ON
IN
LT3010-5
SHDN
SENSE
GND
V
SHDN
V
IN
5.4V TO
80V
(PIN 5)
<0.3V
>2.0V
NC
OUTPUT
OUT
3010 TA01
U
1µF
V
OUT
5V
50mA
Dropout Voltage
350
300
250
200
150
100
DROPOUT VOLTAGE (mV)
50
0
10 20 30 50
0
OUTPUT CURRENT (mA)
40
3010 TA02
3010f
1
Page 2
LT3010/LT3010-5
PACKAGE/ORDER I FOR ATIO
UU
W
WWWU
ABSOLUTE AXI U RATI GS
(Note 1)
IN Pin Voltage................................................... ±80V
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 ............ –65°C to 150°C
Operating Junction Temperature Range
(Notes 3, 10, 11) ......................... –40°C to 125°C
Lead Temperature (Soldering, 10 sec)............ 300°C
TOP VIEW
8
OUT
SENSE/ADJ*
*SENSE FOR LT3010-5, ADJ FOR LT3010
T
JMAX
SEE APPLICATIONS INFORMATION SECTION.
1
2
NC
3
GND
4
MS8E PACKAGE
8-LEAD PLASTIC MSOP
= 125°C, θJA = 40°C/W, θJC = 16°C/W
EXPOSED PAD IS GND
(MUST BE SOLDERED TO PCB)
†
MEASURED AT BOTTOM PAD
7
6
5
IN
NC
NC
SHDN
†
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ORDER PART
NUMBER
LT3010EMS8E
LT3010EMS8E-5
MS8 PART MARKING
LTZF
LTAEF
ELECTRICAL CHARACTERISTICS
The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are at TJ = 25°C.
PARAMETER CONDITIONS MIN TYP MAX UNITS
Minimum Input Voltage LT3010 I
Regulated Output Voltage (Note 3) LT3010-5 VIN = 5.5V, I
ADJ Pin Voltage LT3010 V
(Notes 2,3) 4V < V
Line Regulation LT3010-5 ∆VIN = 5.5V to 80V, I
LT3010 (Note 2) ∆V
Load Regulation LT3010-5 VIN = 6V, ∆I
LT3010 (Note 2) V
Dropout Voltage I
= V
V
IN
OUT(NOMINAL)
(Notes 4, 5) I
GND Pin Current I
= V
V
IN
OUT(NOMINAL)
(Notes 4, 6) I
Output Voltage Noise C
= 1mA 100 150 mV
LOAD
I
= 1mA ● 190 mV
LOAD
= 10mA 200 260 mV
LOAD
I
= 10mA ● 350 mV
LOAD
I
= 50mA 300 370 mV
LOAD
I
= 50mA ● 550 mV
LOAD
= 0mA ● 30 60 µA
LOAD
I
= 1mA ● 100 180 µA
LOAD
= 10mA ● 400 700 µA
LOAD
I
= 50mA ● 1.8 3.3 mA
LOAD
= 10µF, I
OUT
LOAD
ADJ Pin Bias Current (Note 7) 50 100 nA
Shutdown Threshold V
SHDN Pin Current V
(Note 8) V
Quiescent Current in Shutdown V
= Off to On 1.3 2 V
OUT
V
= On to Off 0.3 0.8 V
OUT
= 0V 0.5 2 µA
SHDN
= 6V 0.1 0.5 µA
SHDN
= 6V, V
IN
= 0V 1 5 µA
SHDN
= 50mA ● 34 V
LOAD
= 1mA 4.925 5.000 5.075 V
LOAD
6V < V
IN
= 3V, I
IN
IN
= 3V to 80V, I
IN
V
= 6V, ∆I
IN
= 4V, ∆I
IN
= 4V, ∆I
V
IN
< 80V, 1mA < I
= 1mA 1.258 1.275 1.292 V
LOAD
< 80V, 1mA < I
LOAD
= 1mA to 50mA 25 50 mV
LOAD
= 1mA to 50mA ● 90 mV
LOAD
= 1mA to 50mA 10 20 mV
LOAD
= 1mA to 50mA ● 32 mV
LOAD
< 50mA ● 4.850 5.000 5.150 V
LOAD
< 50mA ● 1.237 1.275 1.313 V
LOAD
= 1mA ● 315mV
LOAD
= 1mA ● 313mV
= 50mA, BW = 10Hz to 100kHz 100 µV
RMS
2
3010f
Page 3
LT3010/LT3010-5
TEMPERATURE (°C)
–50
0
DROPOUT VOLTAGE (mV)
50
150
200
250
500
350
0
50
75
3010 G03
100
400
450
300
–25
25
100
125
IL = 50mA
IL = 10mA
IL = 1mA
ELECTRICAL CHARACTERISTICS
The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are at TJ = 25°C.
PARAMETER CONDITIONS MIN TYP MAX UNITS
Ripple Rejection LT3010 V
LT3010-5 V
Current Limit V
= 7V, V
IN
OUT
LT3010-5 V
LT3010 (Note 2) V
Input Reverse V
= –80V, V
IN
Leakage Current
Reverse Output Current LT3010-5 V
(Note 9) LT3010 (Note 2) V
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: The LT3010 (adjustable version) 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 LT3010
(adjustable version) 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 will add a 5µA DC load on the output.
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 will be equal to (V
IN
– V
DROPOUT
= 7V(Avg), V
IN
= 7V(Avg), V
IN
RIPPLE
RIPPLE
= 0.5V
= 0.5V
P-P
P-P
, f
RIPPLE
, f
RIPPLE
= 120Hz, I
= 120Hz, I
= 50mA 65 75 dB
LOAD
= 50mA 60 68 dB
LOAD
= 0V 140 mA
= 6V, ∆V
IN
= 4V, ∆V
IN
= 0V ● 6mA
OUT
= 5V, VIN < 5V 10 20 µA
OUT
= 1.275V, V
OUT
= –0.1V ● 60 mA
OUT
= –0.1V ● 60 mA
OUT
< 1.275V 8 15 µA
IN
Note 6: GND pin current is tested with V
IN
= V
(nominal) and a current
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 will
decrease 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 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 the GND pin.
Note 10: The LT3010E 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.
TYPICAL PERFOR A CE CHARACTERISTICS
Typical Dropout Voltage
500
450
400
350
300
250
200
150
DROPOUT VOLTAGE (mV)
100
50
0
0
TJ = 125°C
T
105
OUTPUT CURRENT (mA)
= 25°C
J
2015
30 35 45
25
UW
Guaranteed Dropout Voltage Dropout Voltage
600
= TEST POINTS
500
400
300
200
DROPOUT VOLTAGE (mV)
100
0
40
50
3010 G01
10 20 30 40
TJ ≤ 125°C
TJ ≤ 25°C
505015253545
OUTPUT CURRENT (mA)
3010 G02
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3
Page 4
LT3010/LT3010-5
TEMPERATURE (°C)
–50
SHDN PIN THRESHOLD (V)
1.4
25
3010 G12
0.8
0.4
–25 0 50
0.2
0
1.6
1.2
1.0
0.6
75 100 125
OFF-TO-ON
ON-TO-OFF
TEMPERATURE (°C)
–50
OUTPUT VOLTAGE (V)
5.06
25
3010 G05
5.00
4.96
–25 0 50
4.94
4.92
5.08
5.04
5.02
4.98
75 100 125
IL = 1mA
UW
TYPICAL PERFOR A CE CHARACTERISTICS
Quiescent Current LT3010-5 Output VoltageLT3010 ADJ Pin Voltage
40
35
V
= V
SHDN
30
IN
1.295
1.290
1.285
IL = 1mA
10
1.280
1.275
1.270
ADJ PIN VOLTAGE (V)
1.265
1.260
1.255
–25 0 50
–50
LT3010-5 Quiescent CurrentLT3010 Quiescent Current
200
TJ = 25°C
180
= ∞
R
L
160
140
120
100
80
60
QUIESCENT CURRENT (µA)
40
20
0
21
0
25
TEMPERATURE (°C)
V
SHDN
V
SHDN
67 9
43
5
INPUT VOLTAGE (V)
75 100 125
3010 G06
= V
IN
= 0V
8
3010 G07
LT3010 GND Pin Current
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
GND PIN CURRENT (mA)
0.4
0.2
10
0
21
0
INPUT VOLTAGE (V)
TJ = 25°C
*FOR V
OUT
RL = 25.5Ω
= 50mA*
I
L
I
RL = 127Ω
I
= 10mA*
L
RL = 1.27k IL = 1mA*
67 9
43
5
= 1.275V
RL = 51Ω
= 25mA*
L
8
3010 G10
10
25
VIN > 6V
= ∞, IL = 0 (LT3010-5)
R
20
L
R
= 250k, IL = 5µA (LT3010)
L
15
10
QUIESCENT CURRENT (µA)
5
0
–25 0 50
–50
50
TJ = 25°C
45
=
R
L
40
35
30
25
20
15
QUIESCENT CURRENT (µA)
10
5
0
0
V
TEMPERATURE (°C)
∞
21
INPUT VOLTAGE (V)
SHDN
25
V
V
43
= 0V
SHDN
SHDN
5
75 100 125
= V
IN
= 0V
67 9
8
3010 G04
3010 G08
LT3010-5 GND Pin Current
2.0
TJ = 25°C
1.8
*FOR V
1.6
1.4
1.2
1.0
0.8
0.6
GND PIN CURRENT (mA)
0.4
0.2
4
0
0
= 5V
OUT
21
INPUT VOLTAGE (V)
RL = 100Ω
I
RL = 200Ω
I
RL = 500Ω
I
RL = 5k, IL = 1mA*
67 9
43
5
= 50mA*
L
= 25mA*
L
= 10mA*
L
GND Pin Current vs I
2.0
VIN = V
0
T
0
OUT(NOMINAL)
= 25°C
J
105
OUTPUT CURRENT (mA)
1.8
1.6
1.4
1.2
1.0
0.8
0.6
GND PIN CURRENT (mA)
0.4
0.2
8
10
3010 G09
+ 1V
2015
LOAD
30 35 45
25
40
50
3010 G11
SHDN Pin Threshold
3010f
Page 5
UW
TEMPERATURE (°C)
–50
ADJ PIN BIAS CURRENT (nA)
70
25
3010 G15
40
20
–25 0 50
10
0
80
60
50
30
75 100 125
TYPICAL PERFOR A CE CHARACTERISTICS
LT3010/LT3010-5
SHDN Pin Current ADJ Pin Bias Current
0.6
TJ = 25°C
CURRENT FLOWS
OUT OF SHDN PIN
0.5
0.4
0.3
0.2
SHDN PIN CURRENT (µA)
0.1
0
1234
SHDN PIN VOLTAGE (V)
50.50 1.5 2.5 3.5 4.5
3010 G13
Current Limit Reverse Output Current
200
V
= 0V
OUT
180
= 25°C
T
J
160
140
120
100
80
60
CURRENT LIMIT (mA)
40
20
0
21
0
INPUT VOLTAGE (V)
43
5
67 9
8
3010 G16
10
SHDN Pin Current
0.8
V
= 0V
SHDN
CURRENT FLOWS
0.7
OUT OF SHDN PIN
0.6
0.5
0.4
0.3
0.2
SHDN PIN CURRENT (µA)
0.1
0
–25 0 50
–50
Current Limit
200
VIN = 7V
180
V
= 0V
OUT
160
140
120
100
80
60
CURRENT LIMIT (mA)
40
20
0
–50
–25
25
TEMPERATURE (°C)
50
25
0
TEMPERATURE (°C)
75 100 125
3010 G14
100
125
3010 G17
75
100
90
80
70
60
50
40
30
20
REVERSE OUTPUT CURRENT (µA)
10
0
0
TJ = 25°C
V
= 0V
IN
CURRENT FLOWS
INTO OUTPUT PIN
= V
V
OUT
V
OUT
(LT3010-5)
(LT3010)
ADJ
= V
SENSE
LT3010
21
OUTPUT VOLTAGE (V)
(SEE APPLICATIONS
INFORMATION)
LT3010-5
67 9
43
5
ADJ
PIN CLAMP
8
10
3010 G18
24
VIN = 0V
= V
V
OUT
21
= V
V
OUT
18
15
12
9
6
REVERSE OUTPUT CURRENT (µA)
3
0
–25 0 50
–50
= 1.275V (LT3010)
ADJ
= 5V (LT3010-5)
SENSE
LT3010-5
LT3010
25
TEMPERATURE (°C)
75 100 125
3010 G19
Input Ripple RejectionReverse Output Current Input Ripple Rejection
80
78
76
74
72
70
68
66
RIPPLE REJECTION (dB)
64
VIN = 7V + 0.5V
= 50mA
I
L
62
= 1.275V
V
OUT
60
–50
–25
0
TEMPERATURE (°C)
RIPPLE AT f = 120Hz
P-P
50
25
75
100
125
3010 G20
100
VIN = 7V + 50mV
90
= 50mA
I
L
80
70
60
50
40
30
RIPPLE REJECTION (dB)
20
10
0
100 1k 10k 100k 1M
10
FREQUENCY (Hz)
RMS
RIPPLE
C
OUT
= 1µF
C
= 10µF
OUT
3010 G21
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Page 6
LT3010/LT3010-5
UW
TYPICAL PERFOR A CE CHARACTERISTICS
LT3010 Minimum Input Voltage Output Noise Spectral DensityLoad Regulation
4.0
I
= 50mA
LOAD
3.5
3.0
2.5
2.0
1.5
1.0
MINIMUM INPUT VOLTAGE (V)
0.5
0
–25 0 50
–50
25
TEMPERATURE (°C)
75 100 125
3010 G22
0
∆IL = 1mA TO 50mA
–5
–10
–15
–20
–25
LOAD REGULATION (mV)
–30
–35
–40
–25 0 50
–50
LT3010-5 10Hz to 100kHz
Output Noise
V
OUT
100µV/DIV
= 1µF 1ms/DIV 3010 G25
C
OUT
IL = 50mA
LT3010-5
25
TEMPERATURE (°C)
OUTPUT VOLTAGE
10
LT3010
1
0.1
OUTPUT NOISE SPECTRAL DENSITY (µV/√Hz)
75 100 125
3010 G23
0.01
LT3010-5 Transient Response
0.2
0.1
0
–0.1
DEVIATION (V)
–0.2
50
25
0
LOAD CURRENT (mA)
200
0
VIN = 6V
C
IN
C
OUT
∆I
LOAD
400
TIME (µs)
C
= 1µF
OUT
= 50mA
I
L
10 1k 10k 100k
100
= 1µF CERAMIC
= 1µF CERAMIC
= 1mA TO 50mA
600
800
FREQUENCY (Hz)
3010 G24
1000
3010 G26
6
3010f
Page 7
LT3010/LT3010-5
U
UU
PI FU CTIO S
OUT (Pin 1): Output. The output supplies power to the
load. A minimum output capacitor of 1µF is required 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 capacitance and
reverse output characteristics.
SENSE (Pin 2): Sense. For the LT3010-5, the SENSE pin
is the input to the error amplifier. Optimum regulation will
be obtained at the point where the SENSE pin is connected
to the OUT pin of the regulator. In critical applications,
small voltage drops are caused by the resistance (RP) of
PC traces between the regulator and the load. These may
be eliminated by connecting the SENSE pin to the output
at the load as shown in Figure 1 (Kelvin Sense Connection). Note that the voltage drop across the external PC
traces will add to the dropout voltage of the regulator. The
SENSE pin bias current is 10µA at the nominal rated output
voltage.
ADJ (Pin 2): Adjust. For the adjustable LT3010, this is the
input to the error amplifier. This pin is internally clamped
to ±7V. It has a bias current of 50nA which flows into the
pin (see curve of ADJ Pin Bias Current vs Temperature in
R
P
8
IN
LT3010
5
+ +
V
IN
Figure 1. Kelvin Sense Connection
SHDN
GND
OUT
SENSE
4, TAB
1
2
LOAD
3010 F01
the Typical Performance Characteristics). The ADJ pin
voltage is 1.275V referenced to ground, and the output
voltage range is 1.275V to 60V.
GND (Pin 4, Tab): Ground. The exposed backside of the
package is an electrical connection for GND. As such, to
ensure optimum device operation, the exposed pad must
be connected directly to pin 4 on the PC board.
SHDN (Pin 5): Shutdown. The SHDN pin is used to put the
LT3010 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
can be left open circuit. The device will be active, output
on, if the SHDN pin is not connected.
IN (Pin 8): Input. Power is supplied to the device through
the IN pin. A bypass capacitor is required on this pin if the
device is more than six inches away from the main 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 1µF to 10µF is sufficient. The
LT3010 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 LT3010 will act as if there is a
diode in series with its input. There will be no reverse
current flow into the LT3010 and no reverse voltage will
appear at the load. The device will protect both itself and
the load.
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7
Page 8
LT3010/LT3010-5
WUUU
APPLICATIO S I FOR ATIO
The LT3010 is a 50mA high voltage low dropout regulator
with micropower quiescent current and shutdown. The
device is capable of supplying 50mA at a dropout voltage
of 300mV. The low operating quiescent current (30µA)
drops to 1µA in shutdown. In addition to the low quiescent
current, the LT3010 incorporates several protection features 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
battery when the input is pulled to ground, the LT3010 acts
like it has a diode in series with its output and prevents
reverse current flow.
Adjustable Operation
The adjustable version of the LT3010 has an output
voltage range of 1.275V 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 1.275V referenced to ground. The
current in R1 is then equal to 1.275V/R1 and the current
in R2 is the current in R1 plus the ADJ pin bias current.
The ADJ pin bias current, 50nA at 25°C, flows through R2
into the ADJ pin. The output voltage can be calculated
using the formula in Figure 2. The value of R1 should be
less than 250k to minimize errors in the output voltage
caused by the ADJ pin bias current. Note that in shutdown the output is turned off and the divider current will
be zero.
A small capacitor (C1) placed in parallel with the top
resistor (R2) of the output divider is necessary for stability
and transient performance of the adjustable LT3010. The
impedance of C1 at 10kHz should be less than the value of
R1.
The adjustable 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 voltage of 1.275V. Specifications
for output voltages greater than 1.275V will be proportional to the ratio of the desired output voltage to 1.275V;
(V
/1.275V). For example, load regulation for an
OUT
output current change of 1mA to 50mA is –10mV typical
at V
= 1.275V. At V
OUT
= 12V, load regulation is:
OUT
(12V/1.275V) • (–10mV) = –94mV
Output Capacitance and Transient Response
The LT3010 is designed to be stable with a wide range of
output capacitors. The ESR of the output capacitor affects
stability, most notably with small capacitors. A minimum
output capacitor of 1µF with an ESR of 3Ω or less is
recommended to prevent oscillations. The LT3010 is a
micropower device and output transient response will be
a function of output capacitance. Larger values of output
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 LT3010, will increase the
effective output capacitor value.
8
IN
OUT
LT3010
V
IN
V
V
I
OUTPUT RANGE = 1.275V TO 60V
Figure 2. Adjustable Operation
GND
= 1.275V
OUT
= 1.275V
ADJ
= 50nA AT 25°C
ADJ
ADJ
R2 C1
R1
R2
+ (I
)(R2)1 +
()
ADJ
R1
V
OUT
+
3010 F02
3010f
Page 9
WUUU
APPLICATIO S I FOR ATIO
LT3010/LT3010-5
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 dielectrics 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 temperature coefficients as shown in Figures 3 and 4. 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.
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,
20
0
–20
–40
–60
CHANGE IN VALUE (%)
–80
–100
0
26
BOTH CAPACITORS ARE 16V,
1210 CASE SIZE, 10µF
X5R
Y5V
4
8
DC BIAS VOLTAGE (V)
10
14
12
16
3010 F03
similar to the way a piezoelectric accelerometer or microphone 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: I
OUT
• (V
IN
– V
OUT
) and,
2. GND pin current multiplied by the input voltage:
I
• VIN.
GND
The GND pin current can be found by examining the GND
Pin Current curves in the Typical Performance Characteristics. Power dissipation will be equal to the sum of the two
components listed above.
40
20
0
–20
–40
–60
CHANGE IN VALUE (%)
–80
BOTH CAPACITORS ARE 16V,
1210 CASE SIZE, 10µF
–100
–50
–25 0
TEMPERATURE (°C)
X5R
Y5V
50 100 125
25 75
3010 F04
Figure 3. Ceramic Capacitor DC Bias Characterics
Figure 4. Ceramic Capacitor Temperature Characterics
3010f
9
Page 10
LT3010/LT3010-5
WUUU
APPLICATIO S I FOR ATIO
The LT3010 series regulators have internal thermal limiting designed 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 generated by power devices.
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.
Table 1. Measured Thermal Resistance
COPPER AREA
TOPSIDE BACKSIDE BOARD AREA (JUNCTION-TO-AMBIENT)
2500 sq mm 2500 sq mm 2500 sq mm 40°C/W
1000 sq mm 2500 sq mm 2500 sq mm 45°C/W
225 sq mm 2500 sq mm 2500 sq mm 50°C/W
100 sq mm 2500 sq mm 2500 sq mm 62°C/W
THERMAL RESISTANCE
maximum topside and backside area for one ounce copper
is 3 seconds. This time constant will increase as more
thermal mass is added (i.e. vias, larger board, and other
components).
For an application with transient high power peaks, average power dissipation can be used for junction temperature calculations as long as the pulse period is significantly
less than the thermal time constant of the device and
board.
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
50mA, and a maximum ambient temperature of 50°C,
what will the maximum junction temperature be?
The power dissipated by the device will be equal to:
I
OUT(MAX)
• (V
IN(MAX)
– V
OUT
) + (I
GND
• V
IN(MAX)
)
where:
I
OUT(MAX)
V
IN(MAX)
I
GND
at (I
= 50mA
= 30V
= 50mA, V
OUT
= 30V) = 1mA
IN
So:
The thermal resistance junction-to-case (θJC), measured
at the exposed pad on the back of the die, is 16°C/W.
Continuous operation at large input/output voltage differentials 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
P = 50mA • (30V – 5V) + (1mA • 30V) = 1.28W
The thermal resistance will be in the range of 40°C/W to
62°C/W depending on the copper area. So the junction
temperature rise above ambient will be approximately
equal to:
1.31W • 50°C/W = 65.5°C
3010f
10
Page 11
WUUU
APPLICATIO S I FOR ATIO
LT3010/LT3010-5
The maximum junction temperature will then be equal to
the maximum junction temperature rise above ambient
plus the maximum ambient temperature or:
T
= 50°C + 65.5°C = 115.5°C
JMAX
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 50mA for 50ms out of every
250ms, what is the junction temperature rise above ambient? Using a 500ms period (well under the time constant
of the board), power dissipation is as follows:
P1(48V in, 5mA load) = 5mA • (48V – 5V)
+ (200µA • 48V) = 0.23W
P2(48V in, 50mA load) = 50mA • (48V – 5V)
+ (1mA • 48V) = 2.20W
P3(72V in, 5mA load) = 5mA • (72V – 5V)
+ (200µA • 72V) = 0.35W
P4(72V in, 50mA load) = 50mA • (72V – 5V)
+ (1mA • 72V) = 3.42W
Operation at the different power levels is as follows:
76% operation at P1, 19% for P2, 4% for P3, and
1% for P4.
P
= 76%(0.23W) + 19%(2.20W) + 4%(0.35W)
EFF
+ 1%(3.42W) = 0.64W
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 26°C to 38°C.
Protection Features
The LT3010 incorporates several protection features which
make it ideal for use in battery-powered circuits. In addition to the normal protection features associated with
monolithic regulators, such as current limiting and thermal limiting, the device is protected against reverse-input
voltages, and reverse voltages from output to input.
Current limit protection and thermal overload protection
are intended to protect the device against current overload
conditions at the output of the device. For normal operation, the junction temperature should not exceed 125°C.
The input of the device will withstand reverse voltages of
80V. Current flow into the device will be limited to less than
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.
The ADJ pin of the adjustable device can be pulled above
or below ground by as much as 7V without damaging the
device. If the input is left 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. If the input is powered
by a voltage source, pulling the ADJ pin below the reference voltage will cause the device to try and force the
current limit current out of the output. This will cause the
output to go to a unregulated high voltage. Pulling the ADJ
pin above the reference voltage will turn off all output
current.
3010f
11
Page 12
LT3010/LT3010-5
WUUU
APPLICATIO S I FOR ATIO
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
from the 1.22V reference when the output is forced to 60V.
The top resistor of the resistor divider must be chosen to
limit the current into the ADJ pin to less than 5mA when the
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.
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
100
TA = 25°C
90
V
= 0V
IN
CURRENT FLOWS
80
INTO OUTPUT PIN
= V
V
70
V
60
(LT3010-5)
50
40
30
20
REVERSE OUTPUT CURRENT (µA)
10
0
0123
OUT
OUT
(LT3010)
ADJ
= V
SENSE
LT3010
LT3010-5
4
OUTPUT VOLTAGE (V)
open circuit. Current flow back into the output will follow
the curve shown in Figure 5. 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 LT3010 is forced below the OUT pin
or the OUT pin is pulled above the IN pin, input current will
typically drop to less than 2µA. This can happen if the input
of the LT3010 is connected to a discharged (low voltage)
battery and the output is held up by either a backup battery
or a second regulator circuit. The state of the SHDN pin will
have no effect on the reverse output current when the
output is pulled above the input.
ADJ
PIN CLAMP
(SEE ABOVE)
678910
5
3010 F05
12
Figure 5. Reverse Output Current
3010f
Page 13
TYPICAL APPLICATIO S
5V Buck Converter with Low Current Keep Alive Backup
U
D2
D1N914
LT3010/LT3010-5
V
IN
5.5V*
TO 60V
OPERATING
CURRENT
HIGH
LOW
C3
4.7µF
100V
CERAMIC
6
BOOST
4
V
IN
15
SHDN
14
SYNC
GND
1, 8, 9, 16
8
LT3010-5
5
SHDN
LT1766
GND
SENSE
4
SW
BIAS
V
C
OUTIN
FB
11
C
1nF
C2
0.33µF
2
D1
10MQ060N
10
12
C
1
2
†
L1
15µH
R1
15.4k
R2
4.99k
*
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
+
C1
100µF 10V
SOLID
TANTALUM
3010 TA03
V
OUT
5V
1A/50mA
Buck Converter
Efficiency vs Load Current
100
EFFICIENCY (%)
90
80
70
60
50
V
OUT
L = 68µH
0
= 5V
0.25
0.50
LOAD CURRENT (A)
VIN = 10V
VIN = 42V
0.75
1.00
1.25
3010 TA04
3010f
13
Page 14
LT3010/LT3010-5
TYPICAL APPLICATIO
U
LT3010 Automotive Application
V
IN
12V
(LATER 42V)
OFF
ON
V
OFF
48V
ON
(72V TRANSIENT)
+
1µF
NO PROTECTION
DIODE NEEDED!
SHDN
LT3010-5
SENSE
GND
OUTIN
1µF
LT3010 Telecom Application
IN
1µF
SHDN
LT3010-5
GND
OUTIN
SENSE
NO PROTECTION
DIODE NEEDED!
1µF
Constant Brightness for Indicator LED over Wide Input Voltage Range
RETURN
OFF ON
–48V
I
= 1.275V/R
LED
–48V CAN VARY FROM –4V TO –80V
1µF
SET
IN
LT3010
SHDN
GND
OUT
ADJ
R
1µF
SET
3010 TA06
LOAD: CLOCK,
SECURITY SYSTEM
ETC
LOAD:
SYSTEM MONITOR
ETC
3010 TA05
+
BACKUP
BATTERY
–
14
3010f
Page 15
PACKAGE DESCRIPTIO
2.794 ± 0.102
(.110 ± .004)
U
MS8E Package
8-Lead Plastic MSOP
(Reference LTC DWG # 05-08-1662)
0.889 ± 0.127
(.035 ± .005)
BOTTOM VIEW OF
EXPOSED PAD OPTION
1
LT3010/LT3010-5
2.06 ± 0.102
(.080 ± .004)
1.83 ± 0.102
(.072 ± .004)
5.23
(.206)
MIN
0.42 ± 0.04
(.0165 ± .0015)
TYP
RECOMMENDED SOLDER PAD LAYOUT
0.254
(.010)
GAUGE PLANE
0.18
(.077)
NOTE:
1. DIMENSIONS IN MILLIMETER/(INCH)
2. DRAWING NOT TO SCALE
3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS.
MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.
INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX
DETAIL “A”
DETAIL “A”
2.083
(.082 ± .004)
0.65
(.0256)
BSC
° – 6° TYP
0
0.53 ± 0.015
(.021 ± .006)
± 0.102
3.2 – 3.45
(.126 – .136)
SEATING
PLANE
3.00 ± 0.102
(.118 ± .004)
(NOTE 3)
4.90
± 0.15
(1.93 ± .006)
0.22 – 0.38
(.009 – .015)
TYP
1.10
(.043)
MAX
8
8
12
0.65
(.0256)
BSC
7
0.52
5
4
(.206)
REF
3.00 ± 0.102
(.118 ± .004)
NOTE 4
0.86
(.034)
REF
0.13 ± 0.076
(.005 ± .003)
MSOP (MS8E) 0802
6
3
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 representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
3010f
15
Page 16
LT3010/LT3010-5
RELATED PARTS
PART NUMBER DESCRIPTION COMMENTS
LT1020 125mA, Micropower Regulator and Comparator VIN: 4.5V to 36V, V
Comparator and Reference, Class B Outputs, S16, PDIP14 Packages
LT1120/LT1120A 125mA, Micropower Regulator and Comparator VIN: 4.5V to 36V, V
Comparator and Reference,Logic Shutdown, Ref Sources and Sinks 2/4mA,
S8, N8 Packages
LT1121/ 150mA, Micropower, LDO VIN: 4.2V to 30/36V, V
LT1121HV Reverse Battery Protection, SOT-223, S8, Z Packages
LT1129 700mA, Micropower, LDO VIN: 4.2V to 30V, V
DD, S0T-223, S8,TO220-5, TSSOP20 Packages
LT1616 25V, 500mA (I
), 1.4MHz, High Efficiency VIN: 3.6V to 25V, V
OUT
Step-Down DC/DC Converter
LT1676 60V, 440mA (I
), 100kHz, High Efficiency VIN: 7.4V to 60V, V
OUT
Step-Down DC/DC Converter
LT1761 100mA, Low Noise Micropower, LDO VIN: 1.8V to 20V, V
Low Noise < 20µV
LT1762 150mA, Low Noise Micropower, LDO VIN: 1.8V to 20V, V
Low Noise < 20µV
LT1763 500mA, Low Noise Micropower, LDO VIN: 1.8V to 20V, V
Low Noise < 20µV
LT1764/LT1764A 3A, Low Noise, Fast Transient Response, LDO VIN: 2.7V to 20V, V
Low Noise < 40µV
DD, TO220-5 Packages
LT1766 60V, 1.2A (I
), 200kHz, High Efficiency VIN: 5.5V to 60V, V
OUT
Step-Down DC/DC Converter
LT1776 40V, 550mA (I
), 200kHz, High Efficiency VIN: 7.4V to 40V, V
OUT
Step-Down DC/DC Converter
LT1934/ 300mA/60mA, (I
), Constant Off-Time, High 90% Efficiency, VIN: 3.2V to 34V, V
OUT
LT1934-1 Efficiency Step-Down DC/DC Converter ThinSOT Package
LT1956 60V, 1.2A (I
), 500kHz, High Efficiency VIN: 5.5V to 60V, V
OUT
Step-Down DC/DC Converter
LT1962 300mA, Low Noise Micropower, LDO VIN: 1.8V to 20V, V
Low Noise < 20µV
LT1963/LT1963A 1.5A, Low Noise, Fast Transient Response, LDO VIN: 2.1V to 20V, V
Low Noise < 40µV
DD, TO220-5, S0T-223, S8 Packages
LT1964 200mA, Low Noise Micropower, Negative LDO VIN: –0.9V to –20V, V
Low Noise < 30µV
= 2.5V, VDO = 0.4V, IQ = 40µA, ISD = 40µA,
OUT
= 2.5V, VDO = 0.4V, IQ = 40µA, ISD = 10µA,
OUT
= 3.75V, VDO = 0.42V, IQ = 30µA, ISD = 16µA,
OUT
= 3.75V, VDO = 0.4V, IQ = 50µA, ISD = 16µA,
OUT
= 1.25V, IQ = 1.9mA, ISD = <1µA, ThinSOT Package
OUT
= 1.24V, IQ = 3.2mA, ISD = 2.5µA, S8 Package
OUT
= 1.22V, VDO = 0.3V, IQ = 20µA, ISD = <1µA,
OUT
, Stable with 1µF Ceramic Capacitors, ThinSOT Package
RMS P-P
= 1.22V, VDO = 0.3V, IQ = 25µA, ISD = <1µA,
OUT
, MS8 Package
RMS P-P
= 1.22V, VDO = 0.3V, IQ = 30µA, ISD = <1µA,
OUT
, S8 Package
RMS P-P
= 1.21V, VDO = 0.34V, IQ = 1mA, ISD = <1µA,
OUT
, “A” Version Stable with Ceramic Capacitors,
RMS P-P
= 1.20V, IQ = 2.5mA, ISD = 25µA, TSSOP16/E Package
OUT
= 1.24V, IQ = 3.2mA, ISD = 30µA, N8, S8 Packages
OUT
= 1.25V, IQ = 14µA, ISD = <1µA,
OUT
= 1.20V, IQ = 2.5mA, ISD = 25µA, TSSOP16/E Package
OUT
= 1.22V, VDO = 0.27V, IQ = 30µA, ISD = <1µA,
OUT
, MS8 Package
RMS P-P
= 1.21V, VDO = 0.34V, IQ = 1mA, ISD = <1µA,
OUT
, “A” Version Stable with Ceramic Capacitors,
RMS P-P
= –1.21V, VDO = 0.34V, IQ = 30µA, ISD = 3µA,
OUT
, Stable with Ceramic Capacitors, ThinSOT Package
RMS P-P
16
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com
3010f
LT/TP 0403 2K • PRINTED IN USA
LINEAR TECHNOLOGY CORP ORATION 2003
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