LT3061 - 45V VIN, Micropower, Low Noise, 100mA LDO with Output Discharge

LT3061
45V VIN, Micropower,
Low Noise, 100mA LDO
with Output Discharge
Description
Features
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Input Voltage Range: 1.6V to 45V
Output Current: 100mA
Output Discharge
Quiescent Current: 45µA
Dropout Voltage: 250mV
Low Noise: 30µVRMS (10Hz to 100kHz)
Adjustable Output (VREF = 600mV)
Output Tolerance: ±2% Over Load, Line, and
Temperature
Single Capacitor Soft-Starts Reference and Lowers
Output Noise
Shutdown Current: < 3µA
Reverse Battery Protection
Current Limit Foldback and Thermal Limit Protection
8-Lead 2mm × 3mm DFN and MSOP Packages
Applications
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The LT®3061 is a micropower, low dropout (LDO) linear
regulator that operates over a 1.6V to 45V supply range.
The device supplies 100mA of output current with a typical dropout voltage of 250mV. A single external capacitor
provides programmable low noise reference performance
and output soft-start functionality. The LT3061’s quiescent
current is merely 45μA and provides fast transient response
with a minimum 3.3μF output capacitor. In shutdown,
quiescent current is less than 3μA and the reference soft
start capacitor is reset.
The LT3061 features an NMOS pull-down that discharges
the output when SHDN or IN is driven low.
Internal protection circuitry includes reverse-battery
protection, reverse-current protection, current limit with
foldback and thermal shutdown.
The LT3061 is available as an adjustable device with an
output voltage range from the 600mV reference up to 19V.
The LT3061 is offered in the thermally enhanced 8-lead
2mm × 3mm DFN and MSOP packages.
Battery Powered Systems
Automotive Power Supplies
Industrial Power Supplies
Avionic Power Supplies
Portable Instruments
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property
of their respective owners.
Typical Application
Output Discharge
vs VOUT CREF/BYP = 0
1.8V Low Noise Regulator
VIN
2.2V
1µF
VOUT
1.8V
100mA
OUT
118k
1%
LT3061
SHDN
GND
10V
10µF
ADJ
59k
1%
BYP
12V
2V/DIV
IN
0.01µF
8V
6V
5V
3.3V
2V
1.2V
0V
SHDN: 0 TO 1V
3061 TA01
1ms/DIV
3061 TA01a
VIN = VOUT +1V
COUT = 10µF
IFB-DIVIDER = 10µA
3061f
For more information www.linear.com/LT3061
1
LT3061
Absolute Maximum Ratings
(Note 1)
IN Pin Voltage..........................................................±50V
OUT Pin Voltage............................................... +20V, –1V
Input to Output Differential Voltage (Note 2)............±50V
ADJ Pin Voltage.......................................................±50V
SHDN Pin Voltage....................................................±50V
REF/BYP Pin Voltage..................................... –0.3V to 1V
Output Short-Circuit Duration........................... Indefinite
Operating Junction Temperature (Notes 3, 5, 12)
LT3061E, LT3061I............................... –40°C to 125°C
LT3061MP.......................................... –55°C to 150°C
LT3061H............................................. –40°C to 150°C
Storage Temperature Range................... –65°C to 150°C
Lead Temperature (Soldering, 10 sec)
MS8E Package Only........................................... 300°C
Pin Configuration
TOP VIEW
ADJ 2
OUT 3
TOP VIEW
8 GND
REF/BYP 1
9
GND
REF/BYP
ADJ
OUT
OUT
7 SHDN
6 IN
5 IN
OUT 4
1
2
3
4
9
GND
8
7
6
5
GND
SHDN
IN
IN
MS8E PACKAGE
8-LEAD PLASTIC MSOP
DCB PACKAGE
8-LEAD (2mm × 3mm) PLASTIC DFN
TJMAX = 150°C, θJA = 38°C/W TO 45°C/W, θJC = 3.5°C/W
EXPOSED PAD (PIN 9) IS GND, MUST BE SOLDERED TO PCB
TJMAX = 150°C, θJA = 29°C/W TO 45°C/W, θJC = 5°C/W TO 10°C/W
EXPOSED PAD (PIN 9) IS GND, MUST BE SOLDERED TO PCB
Order Information
LEAD FREE FINISH
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LT3061EDCB#PBF
LT3061EDCB#TRPBF
LGNF
8-Lead (2mm × 3mm) Plastic DFN
–40°C to 125°C
LT3061IDCB#PBF
LT3061IDCB#TRPBF
LGNF
8-Lead (2mm × 3mm) Plastic DFN
–40°C to 125°C
LT3061HDCB#PBF
LT3061HDCB#TRPBF
LGNF
8-Lead (2mm × 3mm) Plastic DFN
–40°C to 150°C
LT3061MPDCB#PBF
LT3061MPDCB#TRPBF
LGNF
8-Lead (2mm × 3mm) Plastic DFN
–55°C to 150°C
LT3061EMS8E#PBF
LT3061EMS8E#TRPBF
LTGNG
8-Lead Plastic MSOP
–40°C to 125°C
LT3061IMS8E#PBF
LT3061IMS8E#TRPBF
LTGNG
8-Lead Plastic MSOP
–40°C to 125°C
LT3061HMS8E#PBF
LT3061HMS8E#TRPBF
LTGNG
8-Lead Plastic MSOP
–40°C to 150°C
LT3061MPMS8E#PBF
LT3061MPMS8E#TRPBF
LTGNG
8-Lead Plastic MSOP
–55°C to 150°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Consult LTC Marketing for information on nonstandard lead based finish parts.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
2
3061f
For more information www.linear.com/LT3061
LT3061
Electrical Characteristics
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. (Note 3)
PARAMETER
CONDITIONS
MIN
TYP
Minimum Input Voltage (Note 4)
ILOAD = 100mA
ADJ Pin Voltage (Notes 4, 5)
VIN = 2.1V, ILOAD = 1mA
2.1V < VIN < 45V, 1mA < ILOAD < 100mA (E-, I-Grades)
2.1V < VIN < 45V, 1mA < ILOAD < 100mA (MP-, H-Grades)
1.6
2.1
V
594
588
585
600
600
600
606
612
612
mV
mV
mV
l
l
Line Regulation (Note 4)
ΔVIN = 2.1V to 45V, ILOAD = 1mA (E-, I-Grades)
ΔVIN = 2.1V to 45V, ILOAD = 1mA (MP-, H-Grades)
l
l
0.5
4
6
mV
mV
Load Regulation (Note 4)
VIN = 2.1V, ∆ILOAD = 1mA to 100mA (E-, I-Grades)
VIN = 2.1V, ∆ILOAD = 1mA to 100mA (MP-, H-Grades)
l
l
0.2
4
9
mV
mV
Dropout Voltage
VIN = VOUT(NOMINAL)
(Notes 6, 7)
ILOAD = 1mA
ILOAD = 1mA
65
l
110
180
mV
mV
ILOAD = 10mA
ILOAD = 10mA
130
l
180
270
mV
mV
ILOAD = 50mA
ILOAD = 50mA
195
l
240
350
mV
mV
ILOAD = 100mA
ILOAD = 100mA
250
l
290
430
mV
mV
GND Pin Current
VIN = VOUT(NOMINAL) + 0.6V
(Notes 6, 8)
ILOAD = 0
ILOAD = 1mA
ILOAD = 10mA
ILOAD = 50mA
ILOAD = 100mA
l
l
l
l
l
45
70
225
0.8
2
90
120
500
1.8
4
µA
µA
µA
mA
mA
Output Voltage Noise
COUT = 10µF, ILOAD = 100mA, CREF/BYP = 0.01µF
VOUT = 600mV, BW = 10Hz to 100kHz
ADJ Pin Bias Current (Notes 4, 9)
l
MAX
30
l
Shutdown Threshold
VOUT = Off to On
VOUT = On to Off
l
l
SHDN Pin Current (Note 10)
VSHDN = 0V
VSHDN = 45V
l
l
Quiescent Current in Shutdown
VIN = 45V, VSHDN = 0V
Ripple Rejection (Note 4)
VIN – VOUT = 1.5V (AVG), VRIPPLE = 0.5VP-P,
fRIPPLE = 120Hz, ILOAD = 100mA
Current Limit
VIN = 7V, VOUT = 0
VIN = VOUT(NOMINAL) + 1V (Note 11), ΔVOUT = –5%
l
Input Reverse Leakage Current
VIN = -45V, VOUT = 0
l
Output Discharge Time (Note 6)
VOUT Discharged to 10% of Nominal, COUT = 10μF
l
Reverse Output Current
VOUT = 3.3V, VIN = VSHDN = 2.1V
0.3
70
110
UNITS
µVRMS
15
60
nA
0.8
0.7
1.5
V
V
1.2
<1
3
µA
µA
1.25
3
µA
85
dB
180
mA
mA
1
mA
0.75
2
ms
2.5
15
µA
3061f
For more information www.linear.com/LT3061
3
LT3061
Electrical Characteristics
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: Absolute maximum input to output differential voltage is not
achievable with all combinations of rated IN pin and OUT pin voltages.
With the IN pin at 50V, the OUT pin may not be pulled below 0V. The total
measured voltage from IN to OUT must not exceed ±50V.
Note 3: The LT3061 is tested and specified under pulse load conditions
such that TJ ≅ TA. The LT3061E regulators are 100% tested at TA = 25°C
and performance is guaranteed from 0°C to 125°C. Performance at
–40°C to 125°C is assured by design, characterization and correlation
with statistical process controls. The LT3061I regulators are guaranteed
over the full –40°C to 125°C operating junction temperature range. The
LT3061MP regulators are 100% tested over the –55°C to 150°C operating
junction temperature. The LT3061H regulators are 100% tested at the
150°C operating junction temperature. High junction temperatures degrade
operating lifetimes. Operating lifetime is derated at junction temperature
greater than 125°C.
Note 4: The LT3061 is tested and specified for these conditions with the
ADJ connected to the OUT pin.
Note 5: Maximum junction temperature limits operating conditions. The
regulated output voltage specification does not apply for all possible
combinations of input voltage and output current. Limit the output current
range if operating at the maximum input voltage. Limit the input-to-output
voltage differential if operating at maximum output current. Current limit
foldback limits the maximum output current as a function of input-tooutput voltage. See Current Limit vs VIN – VOUT in the Typical Performance
Characteristics section.
4
Note 6: To satisfy minimum input voltage requirements, the LT3061 is
tested and specified for these conditions with an external resistor divider
(bottom 60k, top 230k) for an output voltage of 2.9V. The external resistor
divider adds 10µA of DC load on the output. The external current is not
factored into GND pin current.
Note 7: Dropout voltage is the minimum input-to-output voltage
differential needed to maintain regulation at a specified output current. In
dropout, the output voltage equals: (VIN – VDROPOUT).
Note 8: GND pin current is tested with VIN = VOUT(NOMINAL) + 0.6V and a
current source load. GND pin current will increase in dropout. See GND pin
current curves in the Typical Performance Characteristics section.
Note 9: ADJ pin bias current flows out of the ADJ pin.
Note 10: SHDN pin current flows into the SHDN pin.
Note 11: To satisfy requirements for minimum input voltage, current limit
is tested at VIN = VOUT(NOMINAL) + 1V or VIN = 2.1V, whichever is greater.
Note 12: This IC includes thermal limit which protects the device during
momentary overload conditions. Junction temperature exceeds 125°C
(LT3061E, LT3061I) or 150°C (LT3061MP, LT3061H) if thermal limit
is active. Continuous operation above the specified maximum junction
temperature may impair device reliability.
3061f
For more information www.linear.com/LT3061
LT3061
Typical Performance Characteristics
Guaranteed Dropout Voltage
450
450
400
400
300
TJ = 125°C
250
200
TJ = 25°C
150
100
50
0
= TEST POINTS
300
TJ = 125°C
250
200
150
100
0
0
10 20 30 40 50 60 70 80 90 100
OUTPUT CURRENT (mA)
0
30
20
VIN = 6V
ALL OTHER PINS = 0V
0
–75 –50 –25 0 25 50 75 100 125 150 175
TEMPERATURE (°C)
TJ = 25°C
110 V
OUT = 5V
100 IL = 10µA
604
602
600
598
596
594
1.25
1.00
0.75
0.50
0
1
2
3
4
5 6
VIN (V)
7
8
9
10
3061 G07
50
40
30
0
VSHDN = 0V, RL = 0
0
5
10
15
20 25
VIN (V)
3061 G05
4.0
VIN = VOUT(NOMINAL) +1V
3.0
2.5
2
1.5
1.0
0
35
40
45
3061 G06
3.5
0
30
SHDN Pin Threshold
0.5
0.25
60
10
SHDN PIN THRESHOLD (V)
1.50
70
20
GND Pin Current vs ILOAD
1.75
80
590
588
–75 –50 –25 0 25 50 75 100 125 150 175
TEMPERATURE (°C)
GND PIN CURRENT (mA)
2.00
90
592
GND Pin Current
VOUT = 0.6V
RL = 6Ω, IL = 100mA
RL = 12Ω, IL = 50mA
RL = 60Ω, IL = 10mA
RL = 600Ω, IL = 1mA
IL = 1mA
Quiescent Current
606
3061 G04
2.25
IL = 10mA
100
120
QUIESCENT CURRENT (µA)
ADJ PIN VOLTAGE (mV)
QUIESCENT CURRENT (µA)
40
2.50
150
3061 G03
608
10
200
0
–75 –50 –25 0 25 50 75 100 125 150 175
TEMPERATURE (°C)
10 20 30 40 50 60 70 80 90 100
OUTPUT CURRENT (mA)
IL = 1mA
610
70
50
250
ADJ Pin Voltage
612
VIN = VSHDN = 6V
VOUT = 5V
IL = 10mA
IL = 50mA
300
3061 G02
Quiescent Current
60
IL = 100mA
350
50
50
80
GND PIN CURRENT (mA)
400
TJ = 150°C
350
3061 G01
0.00
Dropout Voltage
450
DROPOUT VOLTAGE (mV)
TJ = 150°C
350
DROPOUT VOLTAGE (mV)
DROPOUT VOLTAGE (mV)
Typical Dropout Voltage
TA = 25°C, unless otherwise noted.
10 20 30 40 50 60 70 80 90 100
ILOAD (mA)
3061 G08
1.5
1.4
1.3
1.2
1.1
1.0
0.9
OFF TO ON
0.8
0.7
0.6
ON TO OFF
0.5
0.4
0.3
0.2
0.1
0
–75 –50 –25 0 25 50 75 100 125 150 175
TEMPERATURE (°C)
3061 G09
3061f
For more information www.linear.com/LT3061
5
LT3061
Typical Performance Characteristics
SHDN Pin Input Current
3.0
2.5
2.5
2.0
1.5
1.0
0.5
ADJ Pin Bias Current
50
SHDN = 45V
40
ADJ PIN BIAS CURRENT (nA)
3.0
SHDN PIN INPUT CURRENT (µA)
SHDN PIN INPUT CURRENT (µA)
SHDN Pin Input Current
TA = 25°C, unless otherwise noted.
2.0
1.5
1.0
0.5
30
20
10
0
–10
–20
–30
–40
0
0
5
10
15 20 25 30 35
SHDN PIN VOLTAGE (V)
40
45
3061 G10
150
125
100
75
VIN = 7V
225 VOUT = 0V
200
175
150
125
100
75
50
50
25
25
0
0
5 10 15 20 25 30 35 40 45
INPUT/OUTPUT VOLTAGE DIFFERENTIAL (V)
OUTPUT DISCHARGE TIME (ms)
175
0
–75 –50 –25 0 25 50 75 100 125 150 175
TEMPERATURE (°C)
Output Discharge Time
COUT = 10µF, VIN = VOUT +1V
OUTPUT DISCHARGE TIME (ms)
6
5
COUT = 10µF
3.5 VIN = VOUT +1V
3.0
2.5
2.0
1.5
OUTPUT DISCHARGE
FOLDBACK STARTS
1.0
0.5
0
0
2
4
6 8 10 12 14 16 18 20
OUTPUT VOLTAGE (V)
3061 G15
3061 G14
3061 G13
7
Output Discharge Time
4.0
250
CURRENT LIMIT (mA)
200
CURRENT LIMIT (mA)
Internal Current Limit
TJ = 150°C
TJ = 125°C
TJ = 25°C
TJ = –40°C
TJ = –55°C
225
3061 G12
3061 G11
Internal Current Limit
250
–50
–75 –50 –25 0 25 50 75 100 125 150 175
TEMPERATURE (°C)
0
–75 –50 –25 0 25 50 75 100 125 150 175
TEMPERATURE (°C)
Output Discharge vs VOUT
CREF/BYP = 0
OUT = 20V
OUT = 12V
OUT = 5V
OUT = 3.3V
OUT = 1.2V
Output Discharge vs VOUT
CREF/BYP = 0
12V
12V
10V
2V/DIV
4
3
5V/DIV 15V
12V
6V
5V
3.3V
2V
1.2V
2
0V
SHDN: 0 TO 1V
1
1ms/DIV
0
–75 –50 –25 0 25 50 75 100 125 150 175
TEMPERATURE (°C)
20V
20V
8V
3061 G17
VIN = VOUT +1V
COUT = 10µF
IFB-DIVIDER = 10µA
0V
SHDN: 0 TO 1V
1ms/DIV
3061 G18
VIN = VOUT +1V
COUT = 10µF
IFB-DIVIDER = 10µA
3061 G16
6
3061f
For more information www.linear.com/LT3061
LT3061
Typical Performance Characteristics
Reverse Output Current
OUTPUT CURRENT (µA)
35
30
25
20
15
10
5
2
4
6
8 10 12 14 16 18 20
VOUT (V)
Input Ripple Rejection
70
60
50
40
30
20
10
0
10
CREF/BYP = CFF = 0
CREF/BYP = 10nF, CFF = 0
CREF/BYP = 10nF, CFF = 10nF
100
10k 100k
1k
FREQUENCY (Hz)
1M
10M
100
60
COUT = 10µF
VOUT = 5V
50
40
30
20
ILOAD = 100mA
COUT = 3.3µF
10 CREF/BYP = CFF = 0
VIN = VOUT +1.5V +50mVRMS RIPPLE
0
1k
10
100
10k 100k
1M
10M
FREQUENCY (Hz)
3061 G21
80
Minimum Input Voltage
2.2
CREF/BYP = 10nF
90
RIPPLE REJECTION (dB)
RIPPLE REJECTION (dB)
80
70
Input Ripple Rejection
VIN = 6.5V +50mVRMS RIPPLE
ILOAD = 100mA
COUT = 10µF
VOUT = 5V
90
VOUT = 0.6V
80
3061 G20
3061 G19
100
90
CREF/BYP = 0
70
60
50
40
30
20 I
LOAD = 100mA
10 VOUT = 0.6V
VIN = 2.6V +0.5VP-P RIPPLE, f = 120Hz
0
–75 –50 –25 0 25 50 75 100 125 150 175
TEMPERATURE (°C)
3061 G22
2.0
MINIMUM INPUT VOLTAGE (V)
OUTPUT CURRENT (µA)
40
150
140 VOUT = VADJ = 3.3V
V = VSHDN = 2.1V
130 IN
120
110
100
IADJ
90
80
70
60
50
40
30
20
IOUT
10
0
–75 –50 –25 0 25 50 75 100 125 150 175
TEMPERATURE (°C)
RIPPLE REJECTION (dB)
VIN = VSHDN = 2.1V
45 VADJ = VOUT
0
Input Ripple Rejection
Reverse Output Current
50
0
TA = 25°C, unless otherwise noted.
1.8
ILOAD = 100mA
1.6
1.4
1.2
ILOAD = 50mA
1.0
0.8
0.6
0.4
0.2
0.0
–75 –50 –25 0 25 50 75 100 125 150 175
TEMPERATURE (°C)
3061 G23
3061 G24
5V Transient Response
CFF = 0, IOUT = 10mA to 100mA
Load Regulation
5V Transient Response
CFF = 10nF, IOUT = 10mA to 100mA
1
LOAD REGULATION (mV)
0
VOUT
50mV/DIV
–1
VOUT
20mV/DIV
–2
–3
–4
–5
IOUT
50mA/DIV
–6
IOUT
50mA/DIV
–7
∆IL = 1mA TO 100mA
–8 VOUT = 0.6V
VIN = 2.1V
–9
–75 –50 –25 0 25 50 75 100 125 150 175
TEMPERATURE (°C)
100µs/DIV
3061 G26
VIN = 6V
COUT = 10µF
IFB-DIVIDER = 10µA
20µs/DIV
3061 G27
VIN = 6V
COUT = 10µF
IFB-DIVIDER = 10µA
3061 G25
3061f
For more information www.linear.com/LT3061
7
LT3061
Typical Performance Characteristics
1
100
COUT = 10µF
IL = 100mA
1k
10k
FREQUENCY (Hz)
100k
CREF/BYP = 100pF
VOUT = 5V
1
VOUT = 0.6V
0.1
CREF/BYP = 10nF
CREF/BYP = 1nF
COUT = 10µF
IL = 100mA
0.01
10
100
1k
10k
FREQUENCY (Hz)
CREF/BYP = 0
CREF/BYP = 10pF
80
70
60
CREF/BYP = 100pF
50
40
CREF/BYP = 10nF
30
20
CREF/BYP = 100nF
10
0
0.01
0.1
10
1
LOAD CURRENT (mA)
100
OUTPUT NOISE VOLTAGE (µVRMS)
OUTPUT NOISE VOLTAGE (µVRMS)
90
160
150
140
130
120
110
100
90
80
70
60
50
40
30
20
10
0
0.01
VOUT = 5V
VOUT = 3.3V
VOUT = 2.5V
VOUT = 1.2V
VOUT = 0.6V
f = 10Hz TO 100kHz
COUT = 10µF
1
0.1
10
LOAD CURRENT (mA)
100
5V 10Hz to 100kHz Output Noise
CREF/BYP = 10nF, CFF = 0
VOUT
100µV/DIV
CFF = 0
CFF = 10nF
0.1
VOUT = 5V
COUT = 10µF
IL = 100mA
0.01
10
100
CFF = 1nF
10k
1k
FREQUENCY (Hz)
100k
3061 G30
RMS Output Noise
vs Feedforward Capacitor (CFF)
130
f = 10Hz TO 100kHz
120
CREF/BYP = 10nF
VOUT = 5V
COUT = 10µF
110
IFB-DIVIDER = 10µA
100
ILOAD = 100mA
90
80
VOUT = 3.3V
70
VOUT = 2.5V
60
50
40
30
VOUT = 0.6V
20 V
OUT = 1.2V
10
0
0.1
10
0.01
1
FEEDFORWARD CAPACITOR, CFF (nF)
3061 G32
3061 G31
3061 G33
5V 10Hz to 100kHz Output Noise
CREF/BYP = 10nF, CFF = 10nF
VOUT
100µV/DIV
1ms/DIV
COUT = 10µF
ILOAD = 100mA
8
CFF = 100pF
1
RMS Output Noise vs Load Current
CREF/BYP = 10nF, CFF = 0
RMS Output Noise
vs CREF/BYP VOUT = 0.6V
f = 10Hz TO 100kHz
100 COUT = 10µF
10
3061 G29
3061 G28
110
100k
OUTPUT NOISE VOLTAGE (µVRMS)
0.01
10
5V
3.3V
2.5V
1.2V
0.6V
10
OUTPUT NOISE SPECTRAL DENSITY (µV/√Hz)
10
0.1
Output Noise Spectral Density
vs CFF, CREF/BYP = 10nF
Output Noise Spectral Density
vs CREF/BYP = 0, CFF = 0
OUTPUT NOISE SPECTRAL DENSITY (µV/√Hz)
OUTPUT NOISE SPECTRAL DENSITY (µV/√Hz)
Output Noise Spectral Density
CREF/BYP = 0, CFF = 0
TA = 25°C, unless otherwise noted.
3061 G34
1ms/DIV
3061 G35
COUT = 10µF
ILOAD = 100mA
3061f
For more information www.linear.com/LT3061
LT3061
Typical Performance Characteristics
TA = 25°C, unless otherwise noted.
Transient Response, VOUT = 5V
Load Dump, VIN = 12V to 45V
VOUT
5mV/DIV
45V
VIN
10V/DIV
12V
3061 G36
1ms/DIV
COUT = 10µF
CREF/BYP = CFF = 10nF
IFB-DIVIDER = 10µA
SHDN Transient Response
CREF/BYP = 0
SHDN Transient Response
CREF/BYP = 10nF
VOUT
2V/DIV
RL = 500k
VOUT
2V/DIV
RL = 500k
REF/BYP
500mV/DIV
REF/BYP
500mV/DIV
SHDN
1V/DIV
SHDN
1V/DIV
3061 G37
2ms/DIV
2ms/DIV
COUT = 10µF
CFF = 0
3061 G38
COUT = 10µF
CFF = 0
Start-Up Time
vs REF/BYP Capacitor
START-UP TIME (ms)
100
CFF = 0
10
1
0.1
0.01
0.01
0.1
10
1
REF/BYP CAPACITOR (nF)
100
3061 G39
3061f
For more information www.linear.com/LT3061
9
LT3061
Pin Functions
REF/BYP (Pin 1): Reference/ Bypass. Connecting a single
capacitor from this pin to GND bypasses the LT3061’s
reference noise and soft-starts the reference. A 10nF bypass capacitor typically reduces output voltage noise to
30μVRMS in a 10Hz to 100kHz bandwidth. Soft-start time
is directly proportional to the REF/BYP capacitor value.
If the LT3061 is placed in shutdown, REF/BYP is actively
pulled low by an internal device to reset soft-start. If low
noise or soft-start performance is not required, this pin
must be left floating (unconnected). Do not drive this pin
with any active circuitry.
ADJ (Pin 2): Adjust. This pin is the error amplifier’s inverting terminal. Its typical bias current of 15nA flows out of
the pin (see curve of ADJ Pin Bias Current vs Temperature
in the Typical performance Characteristics section). The
ADJ pin voltage is 600mV referenced to GND.
OUT (Pins 3, 4): Output. These pins supply power to the
load. A minimum output capacitor of 3.3µF is required
to prevent oscillations. Large load transient applications
require larger output capacitors to limit peak voltage
transients. See the Applications Information section for
more information on reverse output characteristics. The
output voltage range is 600mV to 19V. If the LT3061 is
placed in shutdown, OUT is actively discharged by an
internal NMOS device. Gate drive is controlled to insure
that a 10μF capacitor is discharged 90% in 2ms or less.
If IN is driven low, OUT is actively discharged to ~800mV.
For OUT voltages greater than 6V, current limit foldback is
implemented to protect the NMOS device and discharge
rates increase. See the Applications Information section
for more information.
10
IN (Pins 5, 6): Input. These pins supply power to the
device. The LT3061 requires a bypass capacitor at IN if
the device is located more than six inches 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 suffices. See Input
Capacitance and Stability in the Application Information
section for more information.
The LT3061 withstands reverse voltages on the IN pin
with respect to the GND and OUT pins. In a reversed input
situation, such as the battery plugged in backwards, the
LT3061 behaves as if a large value resistor is in series with
its input. Limited reverse current flows into the LT3061
and no reverse voltage appears at the load. The device
protects itself and the load.
SHDN (Pin 7): Shutdown. Pulling the SHDN pin low puts
the LT3061 into a low power state and turns the output
off. Drive the SHDN pin with either logic or an open collector/drain with a pull-up resistor. The resistor supplies the
pull-up current to the open collector/drain logic, normally
several microamperes, and the SHDN pin current, typically less than 3µA. If unused, connect the SHDN pin to
VIN. The LT3061 does not function if the SHDN pin is not
connected. The SHDN pin cannot be driven below GND
unless tied to the IN pin. If the SHDN pin is driven below
GND while IN is powered, the output will turn on. SHDN
pin logic cannot be referenced to a negative rail.
GND (Pin 8, Exposed Pad Pin 9): Ground. Connect the
bottom of the external resistor divider that sets the output
voltage directly to GND for optimum regulation. Tie the
exposed pad Pin 9 directly to Pin 8 and the PCB ground.
This exposed pad provides enhanced thermal performance
with its connection to the PCB ground. See the Applications Information section for thermal considerations and
calculating junction temperature.
3061f
For more information www.linear.com/LT3061
LT3061
Applications Information
The LT3061 is a 100mA low dropout regulator with
shutdown. The device is capable of supplying 100mA at
a typical dropout voltage of 250mV and operates over a
1.6V to 45V input range.
and ADJ Pin Bias Current vs Temperature appear in the
Typical Performance Characteristics.
IN
VIN
A single external capacitor provides programmable low
noise reference performance and output soft-start functionality. For example, connecting a 10nF capacitor from
the REF/BYP pin to GND lowers output noise to 30µVRMS
over a 10Hz to 100kHz bandwidth. This capacitor also
soft-starts the reference and prevents output voltage
overshoot at turn-on.
The LT3061’s quiescent current is merely 45μA, while
providing fast transient response with a 3.3µF minimum
low ESR ceramic output capacitor. In shutdown, quiescent current is less than 3μA and the reference soft-start
capacitor and output are reset.
The LT3061 optimizes stability and transient response
with low ESR, ceramic output capacitors. The LT3061
does not require the addition of ESR as is common with
other regulators. The LT3061 has an adjustable output
and typically provides 0.1% line regulation and 0.1%
load regulation. A curve of load regulation appears in the
Typical Performance Characteristics section.
The LT3061 discharges the output in shutdown. Internal
protection circuitry includes reverse-battery protection,
reverse-current protection, current limit with foldback
and thermal shutdown.
Adjustable Operation
The LT3061 has an output voltage range of 0.6V to 19V.
The output voltage is set by the ratio of two external resistors as shown in Figure 1. The device servos the output to
maintain the ADJ pin voltage at 0.6V referenced to ground.
The current in R1 is then equal to 0.6V/R1 and the current
in R2 is the current in R1 plus the ADJ pin bias current.
The ADJ pin bias current, 15nA at 25ºC, flows through R2
into the ADJ pin. Calculate the output voltage using the
formula in Figure 1. The value of R1 should be no greater
than 61.9k to provide a minimum 10µA load current for
stability. The divider does not add to quiescent current in
shutdown because the output is turned off and the divider
current is zero. Curves of ADJ Pin Voltage vs Temperature
OUT
LT3061
SHDN
VOUT
R2
! R2 $
VOUT = 0.6V # 1+ & – (IADJ •R2)
" R1 %
ADJ
GND REF/BYP
VADJ = 0.6V
R1
IADJ = 15nA at 25°C
OUTPUT RANGE = 0.6V to 19V
3061 F01
Figure 1. Adjustable Operation
The LT3061 is tested and specified with the ADJ pin tied to
the OUT pin for an output voltage of 0.6V. Specifications
for output voltages greater than 0.6V are proportional to
the ratio of the desired output voltage to 0.6V: VOUT/0.6V.
For example, load regulation for an output current change
of 1mA to 100mA is –0.2mV typical at VOUT = 0.6V. At
VOUT = 12V, load regulation is:
12V
• ( –0.2mV ) = –4mV
0.6V
Table 1 shows 1% resistor divider values for some common
output voltages with a resistor divider current of 10µA.
Table 1. Output Voltage Resistor Divider Values
VOUT
R1
R2
1.2V
60.4k
60.4k
1.5V
59k
88.7k
1.8V
59k
118k
2.5V
60.4k
191k
3V
59k
237k
3.3V
61.9k
280k
5V
59k
432k
3061f
For more information www.linear.com/LT3061
11
LT3061
Applications Information
The LT3061 regulator provides low output voltage noise
over the 10Hz to 100kHz bandwidth while operating at full
load with the addition of a bypass capacitor (CREF/BYP)
from the REF/BYP pin to GND. A good quality low leakage capacitor is recommended. This capacitor bypasses
the reference of the regulator, providing a low frequency
noise pole for the internal reference. With the use of 10nF
for CREF/BYP, the output voltage noise decreases to as
low as 30µVRMS when the output voltage is set for 0.6V.
For higher output voltages (generated by using a resistor
divider), the output voltage noise gains up accordingly
when using CREF/BYP by itself.
Higher values of output voltage noise may be measured
if care is not exercised with regard to circuit layout and
testing. Crosstalk from nearby traces can induce unwanted
noise onto the LT3061’s output. Power supply ripple rejection must also be considered. The LT3061 regulator does
not have unlimited power supply rejection and will pass
a small portion of the input noise through to the output.
12
IN
VIN
OUT
SHDN
VOUT
R2
LT3061
CFF
COUT
ADJ
GND REF/BYP
R1
10nF
• (I FB–DIVIDER )
10µA
V
I FB–DIVIDER = OUT
R1+ R2
CFF ≥
CREF/BYP
3061 F02
Figure 2. Feedforward Capacitor for Fast Transient Response
VOUT = 5V
COUT = 10µF
IFB-DIVIDER = 10µA
0
VOUT
50mV/DIV
To lower the output voltage noise for higher output voltages, include a feedforward capacitor (CFF) from VOUT
to the ADJ pin. A good quality, low leakage capacitor is
recommended. This capacitor bypasses the error amplifier
of the regulator, providing a low frequency noise pole. With
the use of 10nF for both CFF and CREF/BYP, output voltage
noise decreases to 30µVRMS when the output voltage is
set to 5V by a 10µA feedback resistor divider. If the current in the feedback resistor divider is doubled, CFF must
also be doubled to achieve equivalent noise performance.
Using a feedforward capacitor (CFF) from VOUT to the ADJ
pin has the added benefit of improving transient response
for output voltages greater than 0.6V. With no feedforward
capacitor, the settling time will increase as the output
voltage is raised above 0.6V. Use the equation in Figure 2
to determine the minimum value of CFF to achieve a
transient response that is similar to 0.6V output voltage
performance regardless of the chosen output voltage (see
Figure 3 and Transient Response in the Typical Performance
Characteristics section).
FEEDFORWARD
CAPACITOR, CFF
Bypass Capacitance, Output Voltage Noise and
Transient Response
100pF
1nF
10nF
LOAD CURRENT
100mA/DIV
100µs/DIV
3061 F03
Figure 3. Transient Response vs Feedforward Capacitor
3061f
For more information www.linear.com/LT3061
LT3061
Applications Information
During start-up, the internal reference soft-starts if a reference bypass capacitor is present. Regulator startup time
is directly proportional to the size of the bypass capacitor,
slowing to 6ms with a 10nF bypass capacitor (See SHDN
Transient Response vs REF/BYP Capacitor in the Typical
Performance Characteristics section). The reference bypass capacitor is actively pulled low during shutdown to
reset the internal reference.
Start-up time is also affected by the use of a feedforward
capacitor. Start-up time is directly proportional to the size
of the feedforward capacitor and output voltage, and is
inversely proportional to the feedback resistor divider current, slowing to 15ms with a 10nF feedforward capacitor
and a 10µF output capacitor for an output voltage set to
5V by a 10µA feedback resistor divider.
dielectrics yield much more stable characteristics and are
more suitable for use as the output capacitor. The X7R
type works over a wider temperature range and has better
temperature stability, 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
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 significant 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 verified.
20
Output Capacitance
BOTH CAPACITORS ARE 16V,
1210 CASE SIZE, 10µF
Give extra consideration to the use of ceramic capacitors.
Manufacturers make ceramic capacitors with a variety of
dielectrics, each with different behavior across temperature and applied voltage. The most common dielectrics
are specified with EIA temperature characteristic codes
of Z5U, Y5V, X5R and X7R. The Z5U and Y5V dielectrics
provide high C-V products in a small package at low cost,
but exhibit strong voltage and temperature coefficients as
shown in Figures 4 and 5. 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
X5R
–20
–40
–60
Y5V
–80
–100
0
2
4
14
8
6
10 12
DC BIAS VOLTAGE (V)
16
3061 F04
Figure 4. Ceramic Capacitor DC Bias Characteristics
40
20
CHANGE IN VALUE (%)
The LT3061 regulator is stable with a wide range of output
capacitors. The ESR of the output capacitor affects stability, most notably with small capacitors. Use a minimum
output capacitor of 3.3µF with an ESR of 3Ω or less to
prevent oscillations. The LT3061 is a micropower device
and output load transient response is 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
LT3061, will increase the effective output capacitor value.
For applications with large load current transients, a low
ESR ceramic capacitor in parallel with a bulk tantalum
capacitor often provides an optimally damped response.
CHANGE IN VALUE (%)
0
X5R
0
–20
–40
Y5V
–60
–80
BOTH CAPACITORS ARE 16V,
1210 CASE SIZE, 10µF
–100
–50 –25
50
25
75
0
TEMPERATURE (°C)
100
125
3061 F05
Figure 5. Ceramic Capacitor Temperature Characteristics
3061f
For more information www.linear.com/LT3061
13
LT3061
Applications Information
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,
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.
The resulting voltages produced can cause appreciable
amounts of noise. A ceramic capacitor produced the trace
in Figure 6 in response to light tapping from a pencil.
Similar vibration induced behavior can masquerade as
increased output voltage noise.
VOUT = 0.6V
COUT = 10µF
CREF/BYP = 10nF
ILOAD = 100mA
VOUT
500µV/DIV
4ms/DIV
3061 F06
Figure 6. Noise Resulting from Tapping on a Ceramic Capacitor
Input Capacitance and Stability
Low ESR, ceramic input bypass capacitors are acceptable
for applications without long input leads. However, applications connecting a power supply to an LT3061 circuit’s
IN and GND pins with long input wires combined with a
low ESR, ceramic input capacitor are prone to voltage
spikes, reliability concerns and application-specific board
oscillations.
The input wire inductance found in many battery-powered
applications, combined with the low ESR ceramic input
capacitor, forms a high Q LC resonant tank circuit. In
some instances this resonant frequency beats against the
output current dependent LDO bandwidth and interferes
with proper operation. Simple circuit modifications/solutions are then required. This behavior is not indicative of
LT3061 instability, but is a common ceramic input bypass
capacitor application issue.
14
The self-inductance, or isolated inductance, of a wire is
directly proportional to its length. Wire diameter is not a
major factor on its self-inductance. For example, the selfinductance of a 2-AWG isolated wire (diameter = 0.26") is
about half the self-inductance of a 30-AWG wire (diameter
= 0.01"). One foot of 30-AWG wire has approximately
465nH of self-inductance.
Two methods can reduce wire self-inductance. One method
divides the current flowing towards the LT3061 between
two parallel conductors. In this case, the farther apart the
wires are from each other, the more the self-inductance is
reduced; up to a 50% reduction when placed a few inches
apart. Splitting the wires connects two equal inductors in
parallel, but placing them in close proximity creates mutual
inductance adding to the self-inductance. The second and
most effective way to reduce overall inductance is to place
both forward and return current conductors (the input
and GND wires) in very close proximity. Two 30-AWG
wires separated by only 0.02”, used as forward and return
current conductors, reduce the overall self-inductance
to approximately one-fifth that of a single isolated wire.
If a battery, mounted in close proximity, powers the LT3061,
a 1µF input capacitor suffices for stability. However, if a
distant supply powers the LT3061, use a larger value input
capacitor. Use a rough guideline of 1µF (in addition to the
1µF minimum) per 8 inches of wire length. The minimum
input capacitance needed to stabilize the application also
varies with power supply output impedance variations.
Placing additional capacitance on the LT3061’s output
also helps. However, this requires an order of magnitude
more capacitance in comparison with additional LT3061
input bypassing. Series resistance between the supply
and the LT3061 input also helps stabilize the application; as little as 0.1Ω to 0.5Ω suffices. This impedance
dampens the LC tank circuit at the expense of dropout
voltage. A better alternative is to use higher ESR tantalum
or electrolytic capacitors at the LT3061 input in place of
ceramic capacitors.
3061f
For more information www.linear.com/LT3061
LT3061
Applications Information
Overload Recovery
Like many IC power regulators, the LT3061 has safe operating area protection. The safe area protection decreases
current limit as input-to-output voltage increases and keeps
the power transistor inside a safe operating region for all
values of input-to-output voltage. The protective design
provides some output current at all values of input-tooutput voltage up to the device breakdown.
When power is first applied, as input voltage rises, the
output follows the input, allowing the regulator to start up
into very heavy loads. During start-up, as the input voltage
is rising, the input-to-output voltage differential is small,
allowing the regulator to supply large output currents. With
a high input voltage, a problem can occur wherein removal
of an output short will not allow the output to recover.
The problem occurs with a heavy output load when the
input voltage is high and the output voltage is low. Common situations include immediately after the removal of a
short-circuit or if the shutdown pin is pulled high after the
input voltage has already been turned on. The load line for
such a load may intersect the output current curve at two
points. If this happens, there are two stable output operating points for the regulator. With this double intersection,
the input power supply may need to be cycled down to
zero and brought up again to make the output recover.
Thermal Considerations
The power handling capability of the device will be limited
by the maximum rated junction temperature (125°C for
LT3061E, LT3061I or 150°C for LT3061MP, LT3061H). Two
components comprise the power dissipated by the device:
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
GND pin current is determined using the GND Pin Current
curves in the Typical Performance Characteristics section.
Power dissipation will be equal to the sum of the two
components listed above.
The LT3061 regulator has internal thermal limiting that protects the device during overload conditions. For continuous
normal conditions, the maximum junction temperature of
125°C (E-grade, I-grade) or 150°C (MP-grade, H-grade)
must not be exceeded. Carefully consider all sources of
thermal resistance from junction to ambient including
other heat sources mounted in proximity to the LT3061.
The undersides of the LT3061 packages have exposed metal
from the lead frame to the die attachment. The package
allows heat to directly transfer from the die junction to the
printed circuit board metal to control maximum operating
junction temperature. The dual-in-line pin arrangement
allows metal to extend beyond the ends of the package
on the topside (component side) of a PCB. Connect this
metal to GND on the PCB. The multiple IN and OUT pins
of the LT3061 also assist in spreading heat to the PCB.
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.
Tables 2 and 3 list thermal resistance for several different
board sizes and copper areas. All measurements were taken
in still air on a 4 layer FR-4 board with 1oz solid internal
planes and 2oz top/bottom external trace planes with a total
board thickness of 1.6mm. The four layers were electrically
isolated with no thermal vias present. PCB layers, copper
weight, board layout and thermal vias will affect the resultant thermal resistance. For more information on thermal
resistance and high thermal conductivity test boards,
refer to JEDEC standard JESD51, notably JESD51-12 and
JESD51-7. Achieving low thermal resistance necessitates
attention to detail and careful PCB layout.
3061f
For more information www.linear.com/LT3061
15
LT3061
Applications Information
Table 2. Measured Thermal Resistance for DFN Package
COPPER AREA
TOPSIDE* BACKSIDE
(mm2)
(mm2)
BOARD AREA
(mm2)
THERMAL RESISTANCE
(JUNCTION-TO-AMBIENT)
2500
2500
2500
38°C/W
1000
2500
2500
38°C/W
225
2500
2500
40°C/W
100
2500
2500
45°C/W
*Device is mounted on topside
Table 3. Measured Thermal Resistance for MSOP Package
COPPER AREA
TOPSIDE* BACKSIDE
(mm2)
(mm2)
2500
BOARD AREA
(mm2)
THERMAL RESISTANCE
(JUNCTION-TO-AMBIENT)
2500
29°C/W
2500
1000
2500
2500
30°C/W
225
2500
2500
32°C/W
100
2500
2500
45°C/W
*Device is mounted on topside
Calculating Junction Temperature
Example: Given an output voltage of 2.5V, an input voltage range of 12V ±5%, an output current range of 0mA
to 50mA and a maximum ambient temperature of 85°C,
what will the maximum junction temperature be?
The power dissipated by the device equals:
IOUT(MAX) • (VIN(MAX)–VOUT) + IGND • VIN(MAX)
where,
Using a DFN package, the thermal resistance will be in
the range of 38°C/W to 45°C/W depending on the copper
area. So the junction temperature rise above ambient will
be approximately equal to:
0.518W • 45°C/W = 23.3°C
The maximum junction temperature equals the maximum
ambient temperature plus the maximum junction temperature rise above ambient or:
TJMAX = 85°C + 23.3°C = 108.3°C
Output Discharge
The LT3061 includes a low resistance medium voltage
NMOS device which rapidly discharges the output voltage
if the part is put in shutdown mode. For a 2.9V output
with a 10μF decoupling capacitor, this NMOS discharges
the output to 290mV in 750µs if SHDN is driven low.
Control circuitry drives the gate of the NMOS high if either
the SHDN pin or the IN pin are driven low. In the case
where the IN pin is driven to ground, the NMOS rapidly
discharges the OUT pin to the threshold voltage of the
NMOS, about 800mV. From 800mV, the external load
will continue to discharge the OUT pin at a reduced rate.
The control circuitry implements protection features which
allow the OUT pin to be driven from –1V to 20V without
damaging the LT3061. Current limit foldback for output
voltages greater than 6V protects the NMOS pull-down,
but increases discharge time for higher output voltages.
4.0
VIN(MAX) = 12.6V
IGND at (IOUT = 50mA, VIN = 12V) = 1mA
So,
P = 50mA • (12.6V – 2.5V) + 1mA • 12.6V = 0.518W
OUTPUT DISCHARGE TIME (ms)
IOUT(MAX) = 50mA
COUT = 10µF
3.5 VIN = VOUT +1V
3.0
2.5
2.0
1.5
OUTPUT DISCHARGE
FOLDBACK STARTS
1.0
0.5
0
0
2
4
6 8 10 12 14 16 18 20
OUTPUT VOLTAGE (V)
3061 F07
Figure 7. Discharge Time vs Output Voltage
16
3061f
For more information www.linear.com/LT3061
LT3061
Applications Information
The LT3061 incorporates several protection features that
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 also protects against reverse-input
voltages and reverse output-to-input voltages.
Current limit protection and thermal overload protection
protect the device against current overload conditions at
the output of the device. The typical thermal shutdown
temperature is 165°C. For normal operation, do not exceed
a junction temperature of 125°C (LT3061E, LT3061I) or
150°C (LT3061MP, LT3061H).
The LT3061 IN pin withstands reverse voltages of 50V. The
device limits current flow to less than 1mA (typically less
than 250µA) and no negative voltage appears at OUT. The
device protects both itself and the load against batteries
that are plugged in backwards.
The SHDN pin cannot be driven below GND unless tied to
the IN pin. If the SHDN pin is driven below GND while IN
is powered, the output will turn on. SHDN pin logic cannot
be referenced to a negative rail.
Several different input/output conditions can occur, some
temporarily until the output capacitor is discharged by the
LT3061. The output voltage may be held up temporarily
or otherwise while the input is pulled to ground, pulled
to some intermediate voltage or left open-circuit. Current
flow back into the OUT pin follows the curve shown in
Figure 8. If the LT3061's IN pin is forced below the OUT
pin or the OUT pin is pulled above the IN pin, regardless
of the state of the SHDN pin, input current typically drops
to less than 3µA.
If IN is pulled near 0V, the output discharge pull-down
NMOS turns on, regardless of the state of the SHDN pin.
The gate drive for the pull-down is supplied by the output
voltage.
50
VIN = VSHDN = 2.1V
45 VADJ = VOUT
40
OUTPUT CURRENT (µA)
Protection Features
35
30
25
20
15
10
The LT3061 incurs no damage if the ADJ pin is pulled
above or below ground by 50V. If the input is left open
circuit or grounded, the ADJ pin performs like a large
resistor (typically 30k) in series with a diode when pulled
above or below ground.
5
0
0
2
4
6
8 10 12 14 16 18 20
VOUT (V)
3061 F08
Figure 8. Reverse Output Current
3061f
For more information www.linear.com/LT3061
17
LT3061
Package Description
Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings.
DCB Package
8-Lead Plastic DFN (2mm × 3mm)
(Reference LTC DWG # 05-08-1718 Rev A)
0.70 ±0.05
1.35 ±0.05
3.50 ±0.05
1.65 ±0.05
2.10 ±0.05
PACKAGE
OUTLINE
0.25 ±0.05
0.45 BSC
1.35 REF
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED
R = 0.115
TYP
R = 0.05
5
TYP
2.00 ±0.10
(2 SIDES)
0.40 ±0.10
8
1.35 ±0.10
1.65 ±0.10
3.00 ±0.10
(2 SIDES)
PIN 1 NOTCH
R = 0.20 OR 0.25
× 45° CHAMFER
PIN 1 BAR
TOP MARK
(SEE NOTE 6)
(DCB8) DFN 0106 REV A
4
0.200 REF
1
0.23 ±0.05
0.45 BSC
0.75 ±0.05
1.35 REF
0.00 – 0.05
BOTTOM VIEW—EXPOSED PAD
NOTE:
1. DRAWING IS NOT A JEDEC PACKAGE OUTLINE
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 THE
TOP AND BOTTOM OF PACKAGE
18
3061f
For more information www.linear.com/LT3061
LT3061
Package Description
Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings.
MS8E Package
8-Lead Plastic MSOP, Exposed Die Pad
(Reference LTC DWG # 05-08-1662 Rev K)
BOTTOM VIEW OF
EXPOSED PAD OPTION
1.88
(.074)
1
1.88 ±0.102
(.074 ±.004)
0.29
REF
1.68
(.066)
0.889 ±0.127
(.035 ±.005)
0.05 REF
5.10
(.201)
MIN
DETAIL “B”
CORNER TAIL IS PART OF
DETAIL “B” THE LEADFRAME FEATURE.
FOR REFERENCE ONLY
NO MEASUREMENT PURPOSE
1.68 ±0.102 3.20 – 3.45
(.066 ±.004) (.126 – .136)
8
3.00 ±0.102
(.118 ±.004)
(NOTE 3)
0.65
(.0256)
BSC
0.42 ±0.038
(.0165 ±.0015)
TYP
8
7 6 5
0.52
(.0205)
REF
RECOMMENDED SOLDER PAD LAYOUT
0.254
(.010)
3.00 ±0.102
(.118 ±.004)
(NOTE 4)
4.90 ±0.152
(.193 ±.006)
DETAIL “A”
0° – 6° TYP
GAUGE PLANE
0.53 ±0.152
(.021 ±.006)
DETAIL “A”
1
2 3
4
1.10
(.043)
MAX
0.86
(.034)
REF
0.18
(.007)
SEATING
PLANE
0.22 – 0.38
(.009 – .015)
TYP
0.65
(.0256)
NOTE:
BSC
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
6. EXPOSED PAD DIMENSION DOES INCLUDE MOLD FLASH. MOLD FLASH ON E-PAD
SHALL NOT EXCEED 0.254mm (.010") PER SIDE.
0.1016 ±0.0508
(.004 ±.002)
MSOP (MS8E) 0213 REV K
3061f
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.
For more
information
www.linear.com/LT3061
19
LT3061
Typical Application
1.8V Low Noise Regulator
IN
VIN
2.2V
118k
1%
LT3061
1µF
VOUT
1.8V
100mA
OUT
SHDN
GND
10µF
ADJ
59k
1%
BYP
0.01µF
3061 TA02
Related Parts
PART
NUMBER
DESCRIPTION
COMMENTS
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LT1763
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LT1962
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LT1964
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340mV Dropout Voltage, Low Noise 30µVRMS , VIN = –1.8V to –20V,
ThinSOT and 3mm × 3mm DFN-8 Packages
LT3008
20mA, 45V, 3µA IQ Micropower LDO
300mV Dropout Voltage, Low IQ: 3µA, VIN = 2V to 45V, VOUT = 0.6V to 44V; ThinSOT and
2mm × 2mm DFN-6 Packages
280mV Dropout Voltage, Low IQ: 3µA, VIN = 1.6V to 20V, 2mm × 2mm DFN-6 and SC70 Packages
LT3009
20mA, 3µA IQ Micropower LDO
LT3050
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Precision Current Limit and Diagnostic
Monitor, Fault Indicator, Reverse Protection; 12-Lead 2mm × 3mm DFN and MSOP Packages.
Functions.
LT3060
45V VIN, Micropower, Low Noise,
100mA Low Dropout Linear Regulator
Input Voltage Range: 1.6V to 45V, Quiescent Current: 40μA, Dropout Voltage: 300mV, Low Noise:
30μVRMS (10Hz to 100kHz), Adjustable Output: VREF = 600mV, 8-Lead 2mm × 2mm DFN and
8-Lead ThinSOT
LT3062
45V VIN, Micropower, Low Noise,
200mA Low Dropout Linear Regulator
Input Voltage Range: 1.6V to 45V, Quiescent Current: 45μA, Dropout Voltage: 300mV, Low Noise:
30μVRMS (10Hz to 100kHz), Adjustable Output: 600mV to 40V, 8-Lead MSOP and 2mm × 3mm DFN
LT3063
45V VIN, Micropower, Low Noise,
200mA Low Dropout Linear Regulator
with Active Output Discharge
Active Output Discharge, Input Voltage Range: 1.6V to 45V, Quiescent Current: 45μA, Dropout
Voltage: 300mV, Low Noise: 30μVRMS (10Hz to 100kHz), Adjustable Output: 600mV to 19V, 8-Lead
MSOP and 2mm × 3mm DFN
LT3082
200mA, Parallelable, Single Resistor,
Low Dropout Linear Regulator
Outputs May Be Paralleled for Higher Output, Current or Heat Spreading, Wide Input Voltage
Range: 1.2V to 40V Low Value Input/Output Capacitors Required: 0.22μF, Single Resistor Sets
Output Voltage Initial Set Pin Current Accuracy: 1%, Low Output Noise: 40μVRMS (10Hz to 100kHz)
Reverse-Battery Protection, Reverse-Current Protection; 8-Lead SOT-23, 3-Lead SOT-223 and
8-Lead 3mm × 3mm DFN Packages
LT3085
500mA, Parallelable, Low Noise,
Low Dropout Linear Regulator
275mV Dropout Voltage (2-Supply Operation), Low Noise: 40µVRMS, VIN: 1.2V to 36V,
VOUT: 0V to 35.7V, Current-Based Reference with 1-Resistor VOUT Set, Directly Parallelable
(No Op Amp Required), Stable with Ceramic Capacitors; MS8E and 2mm × 3mm DFN-6 Packages
LT3092
200mA 2-Terminal Programmable
Current Source
Programmable 2-Terminal Current Source, Maximum Output Current: 200mA Wide Input Voltage
Range: 1.2V to 40V, Resistor Ratio Sets Output Current Initial Set Pin Current Accuracy: 1%,
Current Limit and Thermal Shutdown Protection Reverse-Voltage Protection, Reverse-Current
Protection; 8-Lead SOT-23, 3-Lead SOT-223 and 8-Lead 3mm × 3mm DFN Packages
20 Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
For more information www.linear.com/LT3061
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com/LT3061
3061f
LT 0714 • PRINTED IN USA
 LINEAR TECHNOLOGY CORPORATION 2014