LT3495/LT3495B/
LT3495-1/LT3495B-1
650mA/350mA Micropower
Low Noise Boost Converter
with Output Disconnect
FEATURES
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DESCRIPTION
The LT
®
3495/LT3495B/LT3495-1/LT3495B-1 are low noise
boost converters with integrated power switch, feedback
resistor and output disconnect circuitry. The parts control
power delivery by varying both the peak inductor current
and switch off-time. This novel* control scheme results
in low output voltage ripple as well as high efficiency
over a wide load range. For the LT3495/LT3495-1, the
off-time of the switch is not allowed to exceed a fixed
level, guaranteeing the switching frequency stays above
the audio band for the entire load range. The parts feature
a high performance NPN power switch with a 650mA
and 350mA current limit for the LT3495/LT3495B and
LT3495-1/LT3495B-1 respectively. The quiescent current
is a low 60µA, which is further reduced to less than 0.1µA
in shutdown. The internal disconnect circuitry allows the
output voltage to be isolated from the input during shut-
down. An auxiliary reference input (CTRL pin) overrides
the internal 1.235V feedback reference with any lower
value allowing full control of the output voltage during
operation. The LT3495 series are available in a tiny 10-lead
3mm
×
2mm DFN package.
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Low Quiescent Current
60µA in Active Mode
0.1µA in Shutdown Mode
Low Noise Control Scheme (Switching Frequency
Always Stays Above Audible Range for LT3495/-1)
Integrated Power NPN:
650mA Current Limit (LT3495/B)
350mA Current Limit (LT3495-1/B-1)
Integrated Output Disconnect
Integrated Output Dimming
Wide input range: 2.5V to 16V
Wide output range: Up to 40V
Integrated feedback resistor
Tiny 10-Lead 3mm
×
2mm DFN Package
APPLICATIONS
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OLED Power
Low Noise Power
MP3 Player
L,
LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners. *Patent pending.
TYPICAL APPLICATION
OLED Power Supply from One Li-Ion Cell
V
OUT
PEAK-TO-PEAK RIPPLE (mV)
ONE
Li-Ion
CELL
10µH
4.7µF
SW
V
CC
SHDN
CTRL
CAP
V
OUT
909k
FB
GND
3495 TA01a
Output Voltage Ripple
vs Load Current
50
90
1.0µF 0603
CAPACITOR AT V
OUT
EFFICIENCY (%)
Efficiency vs Load Current
V
IN
= 3.6V
400
LOAD FROM CAP
LOAD FROM V
OUT
320
POWER LOSS (mW)
2.2µF
V
OUT
16V
70mA
1µF
40
80
LT3495
30
70
240
20
60
160
10
2.2µF 1206
CAPACITOR AT V
OUT
10
1
LOAD CURRENT (mA)
100
3495 TA01b
50
80
0
0.1
40
0.1
1
10
LOAD CURRENT (mA)
0
100
3495 TA01c
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LT3495/LT3495B/
LT3495-1/LT3495B-1
ABSOLUTE MAXIMUM RATINGS
(Note 1)
PIN CONFIGURATION
TOP VIEW
GND 1
GND 2
V
CC
3
CTRL 4
SHDN
5
11
10 SW
9
8
7
6
CAP
CAP
V
OUT
FB
V
CC
Voltage ...............................................................16V
SW Voltage ...............................................................40V
CAP Voltage ..............................................................40V
V
OUT
Voltage .............................................................40V
SHDN
Voltage ...........................................................10V
CTRL Voltage ............................................................10V
FB Voltage ................................................................2.5V
Maximum Junction Temperature........................... 125°C
Operating Temperature Range (Note 2).. –40°C to 125°C
Storage Temperature Range................... –65°C to 150°C
DDB PACKAGE
10-LEAD (3mm
×
2mm) PLASTIC DFN
T
JMAX
= 125°C,
θ
JA
= 76°C/W
EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
LT3495EDDB#PBF
LT3495EDDB-1#PBF
LT3495BEDDB#PBF
LT3495BEDDB-1#PBF
TAPE AND REEL
LT3495EDDB#TRPBF
LT3495EDDB-1#TRPBF
LT3495BEDDB#TRPBF
LT3495BEDDB-1#TRPBF
PART MARKING
LDSS
LDSV
LDST
LDSW
PACKAGE DESCRIPTION
10-Lead (3mm
×
2mm) Plastic DFN
10-Lead (3mm
×
2mm) Plastic DFN
10-Lead (3mm
×
2mm) Plastic DFN
10-Lead (3mm
×
2mm) Plastic DFN
TEMPERATURE RANGE
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
Consult LTC Marketing for parts specified with wider operating temperature ranges.
Consult LTC Marketing for information on non-standard 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/
ELECTRICAL CHARACTERISTICS
PARAMETER
Minimum Operating Voltage
Maximum Operating Voltage
FB Voltage
FB Voltage Line Regulation
FB Resistor
Quiescent Current
Quiescent Current in Shutdown
Minimum Switch-Off Time
Maximum Switch-Off Time
Maximum Switch-On Time
Switch Current Limit
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= 3V, V
SHDN
= V
CC
, unless otherwise noted. (Note 2)
CONDITIONS
MIN
TYP
2.2
V
CTRL
= 3V, (Note 3)
FB Voltage = 1.235V
Not Switching
V
SHDN
= 0V, V
CC
= 3V
After Start-Up (Note 4)
During Start-Up (Note 4)
LT3495/LT3495-1, V
FB
= 1.5V
LT3495/LT3495B
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MAX
2.5
16
1.255
77
70
1
UNITS
V
V
V
%/V
kΩ
µA
µA
ns
ns
1.220
74.7
1.235
0.03
76
60
0
200
500
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17
550
26
10
650
35
780
µs
µs
mA
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LT3495/LT3495B/
LT3495-1/LT3495B-1
ELECTRICAL CHARACTERISTICS
PARAMETER
Switch Current Limit
Switch V
CESAT
Switch Leakage Current
PMOS Disconnect Current Limit
PMOS Disconnect V
CAP
– V
OUT
V
CAP
– V
OUT
Clamp Voltage
SHDN
Input Voltage High
SHDN
Input Voltage Low
SHDN
Pin Bias Current
CTRL Pin Bias Current
CTRL to FB Offset
Maximum Shunt Current
V
SHDN
= 3V
V
SHDN
= 0V
V
CTRL
= 0.5V, Current Flows Out of Pin
V
CTRL
= 0.5V
LT3495/LT3495-1, V
FB
= 1.5V
l
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= 3V, V
SHDN
= V
CC
, unless otherwise noted. (Note 2)
CONDITIONS
LT3495-1/LT3495B-1
LT3495/LT3495B, I
SW
= 400mA
LT3495-1/LT3495B-1, I
SW
= 200mA
V
SW
= 5V
After Start-Up
During Start-Up
I
OUT
= 50mA, V
CAP
= 15V
1.5
0.3
5.3
0
20
6
230
8
100
14
250
110
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MIN
275
TYP
350
200
125
0.01
370
150
150
8.7
MAX
450
UNITS
mA
mV
mV
1
450
190
µA
mA
mA
mV
V
V
V
µA
µA
nA
mV
µA
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 LT3495/LT3495B/LT3495-1/LT3495B-1 are guaranteed to
meet performance specifications from 0°C to 125°C 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 3:
Internal reference voltage is determined by finding V
FB
voltage
level which causes quiescent current to increase 150µA above “Not
Switching” level.
Note 4:
If CTRL is overriding the internal reference, Start-Up mode occurs
when V
FB
is less then half the voltage on CTRL. If CTRL is not overriding
the internal reference, Start-Up mode occurs when V
FB
is less then half the
voltage of the internal reference.
TYPICAL PERFORMANCE CHARACTERISTICS
Switching Frequency
vs Load Current
1000
V
CC
= 3.6V
V
OUT
= 16V
FIGURE 7 CIRCUIT
V
OUT
VOLTAGE CHANGE (%)
1.5
T
A
= 25°C unless otherwise noted.
Load Regulation
V
CC
= 3.6V
V
OUT
= 16V
1.0 FIGURE 7 CIRCUIT
V
OUT
VOLTAGE (V)
0
20
60
40
80
LOAD CURRENT (mA)
100
120
3495 G02
V
OUT
vs CTRL Voltage
18
15
12
9
6
3
0
FIGURE 7 CIRCUIT
SWITCHING FREQUENCY (kHz)
800
0.5
0.0
–0.5
–1.0
–1.5
600
400
200
0
0
20
60
40
80
LOAD CURRENT (mA)
100
120
3495 G01
0
0.3
0.9
0.6
CTRL VOLTAGE (V)
1.2
1.5
3495 G03
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LT3495/LT3495B/
LT3495-1/LT3495B-1
TYPICAL PERFORMANCE CHARACTERISTICS
Output Voltage vs Temperature
1.00
OUTPUT VOLTAGE CHANGE (%)
MINIMUM SWITCHING FREQUENCY (kHz)
V
CC
= 3.6V
0.75 V
OUT
= 16V
LOAD = 5mA
0.50 FIGURE 7 CIRCUIT
0.25
0.00
–0.25
–0.50
–0.75
–1.00
–40
0
40
80
TEMPERATURE (°C)
125
3495 G04
T
A
= 25°C unless otherwise noted.
Minimum Switching Frequency
50
FIGURE 7 CIRCUIT
QUIESCENT CURRENT (µA)
100
Quiescent Current - Not Switching
45
90
80
40
70
35
60
30
–40
0
40
80
TEMPERATURE (°C)
125
3495 G05
50
2
4
6
8
10
V
CC
(V)
12
14
16
3495 G06
Quiescent Current vs Temperature
100
300
250
SWITCH V
CESAT
(mV)
200
150
100
50
0
SW Saturation Voltage
vs Switch Current (LT3495)
200
SW Saturation Voltage
vs Switch Current (LT3495-1)
QUIESCENT CURRENT (µA)
90
160
SWITCH V
CESAT
(mV)
80
120
70
80
60
40
50
–40
0
80
40
TEMPERATURE (°C)
125
3495 G07
0
100
200 300 400 500
SWITCH CURRENT (mA)
600
700
0
0
100
200
300
SWITCH CURRENT (mA)
400
3495 G09
3495 G08
SHDN
Current vs
SHDN
Voltage
20
1000
INDUCTOR PEAK CURRENT (mA)
Peak Inductor Current
vs Temperature (LT3495)
V
CC
= 3.6V
V
OUT
= 16V
FIGURE 7 CIRCUIT
600
INDUCTOR PEAK CURRENT (mA)
550
500
450
400
350
Peak Inductor Current
vs Temperature (LT3495-1)
FIGURE 9 CIRCUIT
SHDN
PIN CURRENT (µA)
15
900
10
800
5
700
0
0
2
4
6
8
SHDN
PIN VOLTAGE (V)
10
3495 G10
600
–40
0
40
80
TEMPERATURE (°C)
125
3495 G11
300
–40
0
40
80
TEMPERATURE (°C)
125
3495 G12
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LT3495/LT3495B/
LT3495-1/LT3495B-1
TYPICAL PERFORMANCE CHARACTERISTICS
LT3495 Switching Waveform
at No Load
V
OUT
VOLTAGE
10mV/DIV
AC COUPLED
V
OUT
VOLTAGE
50mV/DIV
AC COUPLED
T
A
= 25°C unless otherwise noted.
LT3495 Switching Waveform
at 10mA
SW VOLTAGE
10V/DIV
SW VOLTAGE
10V/DIV
INDUCTOR CURRENT
100mA/DIV
V
CC
= 3.6V
V
OUT
= 16V
10µs/DIV
3495 G13
INDUCTOR CURRENT
500mA/DIV
V
CC
= 3.6V
V
OUT
= 16V
2µs/DIV
3495 G14
LT3495 Switching Waveform
at 80mA
V
OUT
VOLTAGE
50mV/DIV
AC COUPLED
V
OUT
VOLTAGE
20mV/DIV
AC COUPLED
LT3495B-1 Switching Waveform
at No Load
SW VOLTAGE
10V/DIV
SW VOLTAGE
10V/DIV
INDUCTOR CURRENT
500mA/DIV
V
CC
= 3.6V
V
OUT
= 16V
500ns/DIV
3495 G15
INDUCTOR CURRENT
100mA/DIV
V
CC
= 5V
V
OUT
= 16V
20µs/DIV
3495 G16
LT3495B-1 Switching Waveform
at 10mA
V
OUT
VOLTAGE
50mV/DIV
AC COUPLED
V
OUT
VOLTAGE
50mV/DIV
AC COUPLED
LT3495B-1 Switching Waveform
at 60mA
SW VOLTAGE
10V/DIV
SW VOLTAGE
10V/DIV
INDUCTOR CURRENT
200mA/DIV
V
CC
= 5V
V
OUT
= 16V
2µs/DIV
3495 G17
INDUCTOR CURRENT
200mA/DIV
V
CC
= 5V
V
OUT
= 16V
500ns/DIV
3495 G18
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