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 shutdown)
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 fi xed 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.
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATION
5V Supply with Shutdown
IN
LT3010-5
SHDN
OUT
SENSE
GND
30105 TA01
V
SHDN
V
IN
5.4V TO
80V
(PIN 5)
<0.3V
>2.0V
1μF
OUTPUT
OFF
ON
1μF
V
OUT
5V
50mA
350
300
250
200
150
100
DROPOUT VOLTAGE (mV)
50
0
0
Dropout Voltage
10203050
OUTPUT CURRENT (mA)
40
30105 TA02
30105fc
1
LT3010/LT3010-5
ABSOLUTE MAXIMUM RATINGS
PIN CONFIGURATION
(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
Storage Temperature Range .................. –65°C to 150°C
Operating Junction Temperature Range
(Notes 3, 10, 11)
OUT
SENSE/ADJ*
GND
*SENSE FOR LT3010-5, ADJ FOR LT3010
= 125°C (LT3010E), θJA = 40°C/W, θJC = 16°C/W†
T
JMAX
= 140°C (LT3010H), θJA = 40°C/W, θJC = 16°C/W†
T
JMAX
SEE APPLICATIONS INFORMATION SECTION.
EXPOSED PAD (PIN 9) IS GND, MUST BE SOLDERED TO PCB
TOP VIEW
1
2
NC
3
4
MS8E PACKAGE
8-LEAD PLASTIC MSOP
†MEASURED AT BOTTOM PAD
8
7
9
6
5
IN
NC
NC
SHDN
LT3010E ............................................. –40°C to 125°C
LT3010H ............................................–40°C to 140°C
Lead Temperature (Soldering, 10 sec) ................. 300°C
ORDER INFORMATION
LEAD FREE FINISHTAPE AND REELPART MARKINGPACKAGE DESCRIPTIONTEMPERATURE RANGE
LT3010EMS8E#PBFLT3010EMS8E#TRPBFLTZF8-Lead Plastic MSOP–40°C to 125°C
LT3010EMS8E-5#PBFLT3010EMS8E-5#TRPBFLTAEF8-Lead Plastic MSOP–40°C to 125°C
LT3010HMS8E#PBFLT3010HMS8E#TRPBFLTCLP8-Lead Plastic MSOP–40°C to 140°C
LT3010HMS8E-5#PBFLT3010HMS8E-5#TRPBFLTCLQ8-Lead Plastic MSOP–40°C to 140°C
LEAD BASED FINISHTAPE AND REELPART MARKINGPACKAGE DESCRIPTIONTEMPERATURE RANGE
LT3010EMS8ELT3010EMS8E#TRLTZF8-Lead Plastic MSOP–40°C to 125°C
LT3010EMS8E-5LT3010EMS8E-5#TRLTAEF8-Lead Plastic MSOP–40°C to 125°C
LT3010HMS8ELT3010HMS8E #TRLTCLP8-Lead Plastic MSOP–40°C to 140°C
LT3010HMS8E-5LT3010HMS8E-5 #TRLTCLQ8-Lead Plastic MSOP–40°C to 140°C
Consult LTC Marketing for parts specifi ed with wider operating temperature ranges.
For more information on lead free part marking, go to:
For more information on tape and reel specifi cations, go to:
http://www.linear.com/leadfree/
http://www.linear.com/tapeandreel/
(LT3010E) The
ELECTRICAL CHARACTERISTICS
l denotes the specifi cations which apply over the –40°C to
125°C operating temperature range, otherwise specifi cations are at TJ = 25°C.
PARAMETERCONDITIONSMINTYPMAXUNITS
Minimum Input VoltageLT3010 I
Regulated Output Voltage
(Note 3)
ADJ Pin Voltage (Notes 2, 3)LT3010 VIN = 3V, I
Line RegulationLT3010-5 ΔVIN = 5.5V to 80V, I
Load RegulationLT3010-5 VIN = 6V, ΔI
LT3010-5 V
6V < V
4V < V
LT3010 (Note 2) ΔV
V
= 50mA
LOAD
= 5.5V, I
IN
IN
IN
= 3V to 80V, I
IN
= 6V, ΔI
IN
= 1mA
LOAD
< 80V, 1mA < I
= 1mA
LOAD
< 80V, 1mA < I
= 1mA to 50mA
LOAD
= 1mA to 50mAl
LOAD
LOAD
LOAD
< 50mA l
LOAD
< 50mAl
LOAD
= 1mA
= 1mA
l
4.925
4.850
1.258
1.237
l
34V
5.000
5.000
1.275
1.275
5.075
5.150
1.292
1.313
3
15
3
13
2550
90
mV
mV
mV
mV
30105fc
2
V
V
V
V
LT3010/LT3010-5
ELECTRICAL CHARACTERISTICS
(LT3010E) The l denotes the specifi cations which apply over the –40°C to
= 0.5V
= 0.5V
= 25°C.
J
, f
P-P
RIPPLE
, f
P-P
RIPPLE
= 120Hz, I
= 120Hz, I
LOAD
LOAD
= 50mA
= 50mA
1020
32
100150
190
200260
350
300370
550
l
l
l
l
l
l
0.3
30
100
400
1.8
1.3
1.1
60
180
700
3.3
2V
0.5
0.120.5
65
75
60
68
mV
mV
mV
mV
mV
mV
mV
mV
μA
μA
μA
mA
RMS
μA
μA
dB
dB
140mA
l
60
l
60
l
10
8
6mA
20
15
mA
mA
μA
μA
125°C operating temperature range, otherwise specifi cations are at T
PARAMETERCONDITIONSMINTYPMAXUNITS
= 4V, ΔI
IN
= 4V, ΔI
IN
= 50mA, BW = 10Hz to 100kHz100μV
LOAD
Dropout Voltage
V
= V
IN
OUT(NOMINAL)
(Notes 4, 5)
GND Pin Current
V
= V
IN
OUT(NOMINAL)
(Notes 4, 6)
Output Voltage NoiseC
LT3010 (Note 2) V
V
= 1mA
I
LOAD
I
= 1mAl
LOAD
I
= 10mA
LOAD
I
= 10mAl
LOAD
I
= 50mA
LOAD
I
= 50mAl
LOAD
= 0mA
I
LOAD
I
= 1mA
LOAD
I
= 10mA
LOAD
I
= 50mA
LOAD
= 10μF, I
OUT
ADJ Pin Bias Current (Note 7)50100nA
Shutdown ThresholdV
SHDN Pin Current
(Note 8)
Quiescent Current in Shutdown V
Ripple RejectionLT3010 V
Current LimitV
Input Reverse Leakage Current VIN = –80V, V
Reverse Output Current
(Note 9)
= Off to On
OUT
V
= On to Off
OUT
= 0V
V
SHDN
V
= 6V
SHDN
= 6V, V
IN
= 0V 15μA
SHDN
LT3010-5 V
= 7V, V
IN
OUT
= 0V
LT3010-5 V
LT3010 (Note 2) V
= 0V
OUT
LT3010-5 V
LT3010 (Note 2) V
= 7V(Avg), V
IN
= 7V(Avg), V
IN
= 6V, ΔV
IN
= 4V, ΔV
IN
= 5V, VIN < 5V
OUT
= 1.275V, VIN < 1.275V
OUT
= 1mA to 50mA
LOAD
= 1mA to 50mAl
LOAD
RIPPLE
RIPPLE
= –0.1V
OUT
= –0.1V
OUT
V
(LT3010H) The l denotes the specifi cations which apply over the –40°C to 140°C operating temperature range, otherwise
specifi cations are at TJ = 25°C.
PARAMETERCONDITIONSMINTYPMAXUNITS
Minimum Input VoltageLT3010 I
Regulated Output Voltage
(Note 3)
LT3010-5 V
6V < V
ADJ Pin Voltage (Notes 2, 3)LT3010 VIN = 3V, I
4.25V < V
LOAD
= 5.5V, I
IN
= 50mA
= 1mA
LOAD
< 80V, 1mA < I
IN
= 1mA
LOAD
< 80V, 1mA < I
IN
Line RegulationLT3010-5 ΔVIN = 5.5V to 80V, I
LT3010 (Note 2) ΔV
Load RegulationLT3010-5 VIN = 6V, ΔI
V
LT3010 (Note 2) VIN = 4V, ΔI
V
= 3V to 80V, I
IN
= 6V, ΔI
IN
= 4.25V, ΔI
IN
= 1mA to 50mA
LOAD
= 1mA to 50mAl
LOAD
= 1mA to 50mA
LOAD
LOAD
< 50mA l
LOAD
< 50mAl
LOAD
= 1mA
LOAD
= 1mA
LOAD
= 1mA to 50mAl
l
4.925
4.825
1.258
1.230
l
l
34.25V
5.000
5.000
1.275
1.275
5.075
5.15
1.292
1.313
3
20
3
15
2550
100
1020
45
mV
mV
mV
mV
mV
mV
30105fc
3
V
V
V
V
LT3010/LT3010-5
ELECTRICAL CHARACTERISTICS
(LT3010H) The l denotes the specifi cations which apply over the –40°C to
= 0.5V
= 0.5V
= 25°C.
J
, f
P-P
RIPPLE
, f
P-P
RIPPLE
= 120Hz, I
= 120Hz, I
LOAD
LOAD
= 50mA
= 50mA
100150
220
200260
380
300370
600
l
l
l
l
l
l
0.3
30
100
400
1.8
1.3
0.8
80
200
750
3.5
2V
0.5
0.120.5
65
60
l
l
55
l
55
l
75
68
140mA
6mA
10
20
8
15
mV
mV
mV
mV
mV
mV
μA
μA
μA
mA
RMS
μA
μA
dB
dB
mA
mA
μA
μA
140°C operating temperature range, otherwise specifi cations are at T
PARAMETERCONDITIONSMINTYPMAXUNITS
Dropout Voltage
= V
V
IN
OUT(NOMINAL)
(Notes 4, 5)
GND Pin Current
V
= V
IN
OUT(NOMINAL)
(Notes 4, 6)
Output Voltage NoiseC
ADJ Pin Bias Current (Note 7)50100nA
Shutdown ThresholdV
SHDN Pin Current
(Note 8)
Quiescent Current in Shutdown V
Ripple RejectionLT3010 V
Current LimitV
Input Reverse Leakage Current VIN = –80V, V
Reverse Output Current
(Note 9)
= 1mA
I
LOAD
I
= 1mAl
LOAD
I
= 10mA
LOAD
I
= 10mAl
LOAD
I
= 50mA
LOAD
I
= 50mAl
LOAD
= 0mA
I
LOAD
I
= 1mA
LOAD
I
= 10mA
LOAD
I
= 50mA
LOAD
= 10μF, I
OUT
= Off to On
OUT
V
= On to Off
OUT
= 0V
V
SHDN
V
= 6V
SHDN
= 6V, V
IN
LT3010-5 V
= 7V, V
IN
LT3010-5 V
LT3010 (Note 2) V
LT3010-5 V
LT3010 (Note 2) V
= 250mA, BW = 10Hz to 100kHz100μV
LOAD
= 0V 15μA
SHDN
= 7V(Avg), V
OUT
= 0V
OUT
IN
= 7V(Avg), V
IN
= 6V, ΔV
IN
= 4.25V, ΔV
IN
= 0V
= 5V, VIN < 5V
OUT
= 1.275V, VIN < 1.275V
OUT
OUT
RIPPLE
RIPPLE
= –0.1V
= –0.1V
OUT
V
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.
Note 2: The LT3010 (adjustable version) is tested and specifi ed 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 specifi cation 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 specifi ed 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 specifi ed output current. In dropout, the
output voltage will be equal to (V
Note 6: GND pin current is tested with V
IN
– V
DROPOUT
= V
IN
).
(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 fl ows into the ADJ pin.
Note 8: SHDN pin current fl ows 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 fl ows into the OUT
pin and out the GND pin.
Note 10: The LT3010E is guaranteed to meet performance specifi cations
from 0°C to 125°C operating junction temperature. Specifi cations over
the –40°C to 125°C operating junction temperature range are assured by
design, characterization and correlation with statistical process controls.
The LT3010H is tested to the LT3010H Electrical Characteristics table at
140°C operating junction temperature. High junction temperatures degrade
operating lifetimes. Operating lifetime is derated at junction temperatures
greater than 125°C.
Note 11: This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperature will exceed 125°C (LT3010E) or 140°C (LT3010H) when
overtemperature protection is active. Continuous operation above the
specifi ed maximum operating junction temperature may impair device
reliability.
30105fc
4
LT3010/LT3010-5
TYPICAL PERFORMANCE CHARACTERISTICS
Typical Dropout VoltageGuaranteed Dropout VoltageDropout Voltage
500
450
400
350
300
250
200
150
DROPOUT VOLTAGE (mV)
100
50
0
0
TJ = 125°C
= 25°C
T
J
105201530 35452550
OUTPUT CURRENT (mA)
40
30105 G01
600
500
400
300
200
DROPOUT VOLTAGE (mV)
100
0
= TEST POINTS
TJ ≤ 125°C
TJ ≤ 25°C
10203040
OUTPUT CURRENT (mA)
505015253545
30105 G02
Quiescent CurrentLT3010 ADJ Pin VoltageLT3010-5 Output Voltage
40
35
V
30
25
VIN > 6V
= ∞, IL = 0 (LT3010-5)
R
20
L
= 250k, IL = 5μA (LT3010)
R
L
15
10
QUIESCENT CURRENT (μA)
5
0
–25 050
–50
SHDN
V
25
TEMPERATURE (°C)
SHDN
= V
= 0V
IN
75 100 125 150
30105 G04
1.295
IL = 1mA
1.290
1.285
1.280
1.275
1.270
ADJ PIN VOLTAGE (V)
1.265
1.260
1.255
–50050 75–2525100150125
TEMPERATURE (°C)
30105 G05
500
450
400
350
300
250
200
150
DROPOUT VOLTAGE (mV)
100
50
0
–50050 75–2525100150125
5.08
IL = 1mA
5.06
5.04
5.02
5.00
4.98
OUTPUT VOLTAGE (V)
4.96
4.94
4.92
–50050 75–2525100150125
IL = 50mA
IL = 10mA
IL = 1mA
TEMPERATURE (°C)
TEMPERATURE (°C)
30105 G03
30105 G06
LT3010 Quiescent CurrentLT3010-5 Quiescent CurrentLT3010 GND Pin Current
50
TJ = 25°C
45
= ∞
R
L
40
35
30
25
20
15
QUIESCENT CURRENT (μA)
10
5
0
0
2143679510
INPUT VOLTAGE (V)
V
V
SHDN
SHDN
= V
= 0V
IN
8
30105 G07
200
TJ = 25°C
180
= ∞
R
L
160
140
120
100
80
60
QUIESCENT CURRENT (μA)
40
20
0
0
2143679510
INPUT VOLTAGE (V)
V
V
SHDN
SHDN
= V
= 0V
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
IN
8
30105 G08
GND PIN CURRENT (mA)
0.4
0.2
0
0
2143679510
RL = 25.5Ω
I
I
RL = 1.27k IL = 1mA*
INPUT VOLTAGE (V)
TJ = 25°C
*FOR V
= 50mA*
L
RL = 127Ω
= 10mA*
L
= 1.275V
OUT
RL = 51Ω
= 25mA*
I
L
8
30105 G09
30105fc
5
LT3010/LT3010-5
TYPICAL PERFORMANCE CHARACTERISTICS
LT3010-5 GND Pin CurrentGND Pin Current vs I
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
0
0
= 5V
OUT
2143679510
INPUT VOLTAGE (V)
RL = 100Ω
= 50mA*
I
L
RL = 200Ω
= 25mA*
I
L
RL = 500Ω
= 10mA*
I
L
RL = 5k, IL = 1mA*
8
30105 G10
2.0
VIN = V
1.8
1.6
1.4
1.2
1.0
0.8
0.6
GND PIN CURRENT (mA)
0.4
0.2
0
OUT(NOMINAL)
= 25°C
T
J
0
105201530 35452550
OUTPUT CURRENT (mA)
LOAD
+ 1V
40
30105 G11
SHDN Pin Threshold
1.6
1.4
1.2
1.0
0.8
0.6
0.4
SHDN PIN THRESHOLD (V)
0.2
0
–5025–25 050 75 100 125 150
SHDN Pin CurrentSHDN Pin CurrentADJ Pin Bias Current
LT3010 Minimum Input VoltageLoad RegulationOutput Noise Spectral Density
4.0
I
= 50mA
LOAD
3.5
3.0
2.5
2.0
1.5
1.0
MINIMUM INPUT VOLTAGE (V)
0.5
0
–50050 75–2525100150125
TEMPERATURE (°C)
30105 G22
0
ΔIL = 1mA TO 50mA
–5
–10
–15
–20
–25
–30
–35
LOAD REGULATION (mV)
–40
–45
–50
–50050 75–2525100150125
TEMPERATURE (°C)
LT3010-5
LT3010
30105 G23
10
C
= 1μF
OUT
= 50mA
I
L
1
0.1
OUTPUT NOISE SPECTRAL DENSITY (μV/√Hz)
0.01
101k10k100k
100
FREQUENCY (Hz)
LT3010-5 10Hz to 100kHz
Output NoiseLT3010-5 Transient Response
0.2
0.1
V
OUT
100μV/DIV
C
OUT
= 50mA
I
L
= 1μF
1ms/DIV
30105 G25
0
–0.1
DEVIATION (V)
OUTPUT VOLTAGE
–0.2
50
25
0
LOAD CURRENT (mA)
0
2004006001000
VIN = 6V
= 1μF CERAMIC
C
IN
= 1μF CERAMIC
C
OUT
= 1mA TO 50mA
ΔI
LOAD
TIME (μs)
800
30105 G26
30105 G24
30105fc
7
LT3010/LT3010-5
PIN FUNCTIONS
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 amplifi er. 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 (R
) of
P
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 amplifi er. This pin is internally clamped
to ±7V. It has a bias current of 50nA which fl ows into the
pin (see curve of ADJ Pin Bias Current vs Temperature
R
P
GND
OUT
SENSE
4, 9
1
2
LOAD
30105 F01
8
IN
LT3010
5
++
V
IN
Figure 1. Kelvin Sense Connection
SHDN
in the Typical Performance Characteristics). The ADJ pin
voltage is 1.275V referenced to ground, and the output
voltage range is 1.275V to 60V.
NC (Pins 3, 6, 7): No Connection. May be fl oated, tied to
IN or tied to GND.
GND (Pin 4, Pin 9): Ground. The exposed backside (pin 9)
of the package is an electrical connection for GND. As
such, to ensure optimum device operation, pin 9 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
must be tied to a logic high or V
IN
.
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 fi lter 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 suffi cient. 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 fl ow
into the LT3010 and no reverse voltage will appear at the
load. The device will protect both itself and the load.
8
30105fc
APPLICATIONS INFORMATION
LT3010/LT3010-5
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 fl ow.
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, fl ows 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.
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
R2C1
R1
R2
+ (I
)(R2)1 +
()
ADJ
R1
V
OUT
+
30105 F02
The adjustable device is tested and specifi ed with the
ADJ pin tied to the OUT pin and a 5μA DC load (unless
otherwise specifi ed) for an output voltage of 1.275V. Specifi cations 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.
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 specifi ed with EIA temperature characteristic codes of Z5U, Y5V, X5R and X7R. The Z5U and
Y5V dielectrics are good for providing high capacitances
in a small package, but they tend to have strong voltage
and temperature coeffi cients as shown in Figures 3 and 4.
When used with a 5V regulator, a 16V 10μF Y5V capacitor
can exhibit an effective value as low as 1μF to 2μF for the
DC bias voltage applied and 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. Care still must be exercised when
using X5R and X7R capacitors; the X5R and X7R codes
only specify operating temperature range and maximum
30105fc
9
LT3010/LT3010-5
APPLICATIONS INFORMATION
20
0
–20
–40
–60
CHANGE IN VALUE (%)
–80
–100
04 8102612 14
Figure 3. Ceramic Capacitor DC Bias Characteristics
40
20
0
–20
–40
–60
CHANGE IN VALUE (%)
–80
BOTH CAPACITORS ARE 16V,
1210 CASE SIZE, 10μF
–100
Figure 4. Ceramic Capacitor Temperature Characteristics
–25050100 125
–50
BOTH CAPACITORS ARE 16V,
1210 CASE SIZE, 10μF
X5R
Y5V
DC BIAS VOLTAGE (V)
X5R
Y5V
2575
TEMPERATURE (°C)
16
30105 F03
30105 F04
capacitance change over temperature. Capacitance change
due to DC bias with X5R and X7R capacitors is better than
Y5V and Z5U capacitors, but can still be signifi cant enough
to drop capacitor values below appropriate levels. Capacitor DC bias characteristics tend to improve as component
case size increases, but expected capacitance at operating
voltage should be verifi ed.
Voltage and temperature coeffi cients 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, 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,
LT3010E or 140°C, LT3010H). 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
IN
– V
OUT
) and,
• (V
2. GND pin current multiplied by the input voltage:
• V
I
GND
IN
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.
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 (LT3010E) or 140°C
(LT3010H) 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
BOARD AREA
2500 sq mm 2500 sq mm 2500 sq mm40°C/W
1000 sq mm 2500 sq mm 2500 sq mm45°C/W
225 sq mm2500 sq mm 2500 sq mm50°C/W
100 sq mm2500 sq mm 2500 sq mm62°C/W
THERMAL RESISTANCE
(JUNCTION-TO-AMBIENT)TOPSIDEBACKSIDE
The thermal resistance junction-to-case (θJC), measured
at the exposed pad on the back of the die, is 16°C/W.
10
30105fc
APPLICATIONS INFORMATION
LT3010/LT3010-5
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 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 signifi cantly 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)
= 50mA
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:
Operation at the different power levels is as follows:
76% operation at P1, 19% for P2, 4% for P3, and
1% for P4.
= 76%(0.23W) + 19%(2.20W) + 4%(0.35W)
P
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.
at (I
= 30V
= 50mA, VIN = 30V) = 1mA
OUT
V
IN(MAX)
I
GND
So:
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
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
High Temperature Operation
Care must be taken when designing LT3010/LT3010-5
applications to operate at high ambient temperatures.
The LT3010/LT3010-5 works at elevated temperatures
but erratic operation can occur due to unforeseen variations in external components. Some tantalum capacitors
are available for high temperature operation, but ESR is
often several ohms; capacitor ESR above 3Ω is unsuitable for use with the LT3010/LT3010-5. Ceramic capacitor
manufacturers (Murata, AVX, TDK, and Vishay Vitramon
at this writing) now offer ceramic capacitors that are rated
to 150°C using an X8R dielectric. Device instability will
occur if output capacitor value and ESR are outside design
limits at elevated temperature and operating DC voltage
bias (see information on capacitor characteristics under
30105fc
11
LT3010/LT3010-5
APPLICATIONS INFORMATION
Output Capacitance and Transient Response). Check each
passive component for absolute value and voltage ratings
over the operating temperature range.
Leakages in capacitors or from solder fl ux left after insuffi cient board cleaning adversely affects low quiescent current
operation. Consider junction temperature increase due to
power dissipation in both the junction and nearby components to ensure maximum specifi cations are not violated
for the LT3010/LT3010H or external components.
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
(LT3010E) or 140°C (LT3010H).
The input of the device will withstand reverse voltages
of 80V. Current fl ow 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.
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
open circuit. Current fl ow 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.
100
TA = 25°C
90
= 0V
V
IN
CURRENT FLOWS
80
INTO OUTPUT PIN
= V
V
70
OUT
V
OUT
60
(LT3010-5)
50
40
30
20
REVERSE OUTPUT CURRENT (μA)
10
0
01234567 8910
(LT3010)
ADJ
= V
SENSE
LT3010
LT3010-5
OUTPUT VOLTAGE (V)
ADJ
PIN CLAMP
(SEE ABOVE)
30105 F05
12
Figure 5. Reverse Output Current
30105fc
TYPICAL APPLICATIONS
5V Buck Converter with Low Current Keep Alive Backup
LT3010/LT3010-5
D2
D1N914
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
5
SHDN
LT1766
LT3010-5
GND
4
SW
BIAS
V
C
OUTIN
SENSE
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
30105 TA03
V
OUT
5V
1A/50mA
Buck Converter
Effi ciency vs Load Current
100
90
80
= 5V
V
OUT
L = 68μH
VIN = 10V
VIN = 42V
70
EFFICIENCY (%)
60
50
0
0.250.500.75
LOAD CURRENT (A)
1.00
1.25
30105 TA04
30105fc
13
LT3010/LT3010-5
TYPICAL APPLICATIONS
LT3010 Automotive Application
V
IN
12V
(LATER 42V)
OFF
ON
V
OFF
48V
ON
(72V TRANSIENT)
OUTIN
LT3010-5
SENSE
GND
+
1μF
NO PROTECTION
DIODE NEEDED!
SHDN
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
1μF
LOAD: CLOCK,
SECURITY SYSTEM
SYSTEM MONITOR
ETC
LOAD:
ETC
30105 TA05
+
BACKUP
BATTERY
–
RETURN
1μF
OFF ON
–48V
I
= 1.275V/R
LED
–48V CAN VARY FROM –4V TO –80V
SET
IN
LT3010
SHDN
GND
OUT
ADJ
R
SET
30105 TA06
1μF
14
30105fc
PACKAGE DESCRIPTION
2.794 ± 0.102
(.110 ± .004)
MS8E Package
8-Lead Plastic MSOP
(Reference LTC DWG # 05-08-1662)
EXPOSED PAD OPTION
0.889 ± 0.127
(.035 ± .005)
BOTTOM VIEW OF
1
LT3010/LT3010-5
2.06 ± 0.102
(.081 ± .004)
1.83 ± 0.102
(.072 ± .004)
5.23
(.206)
MIN
0.42 ± 0.038
(.0165 ± .0015)
TYP
RECOMMENDED SOLDER PAD LAYOUT
0.254
(.010)
GAUGE PLANE
0.18
(.007)
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
2.083 ± 0.102
(.082 ± .004)
0.65
(.0256)
BSC
DETAIL “A”
0° – 6° TYP
DETAIL “A”
3.20 – 3.45
(.126 – .136)
0.53 ± 0.152
(.021 ± .006)
SEATING
PLANE
3.00 ± 0.102
(.118 ± .004)
(NOTE 3)
4.90 ± 0.152
(.193 ± .006)
(.043)
0.22 – 0.38
(.009 – .015)
TYP
1.10
MAX
8
8
12
0.65
(.0256)
BSC
7
0.52
5
4
(.0205)
REF
3.00 ± 0.102
(.118 ± .004)
(NOTE 4)
0.86
(.034)
REF
0.1016 ± 0.0508
(.004 ± .002)
MSOP (MS8E) 0307 REV D
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.
30105fc
15
LT3010/LT3010-5
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ThinSOT is a trademark of Linear Technology Corporation.