LT3048 Series
Low Noise Bias Generator
in 2mm
×
2mm DFN
FEATURES
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DESCRIPTION
The
LT
®
3048
series generate low noise, low ripple bias
supplies from input voltages of 2.7V to 4.8V.
The LT3048 includes a boost regulator and a LDO linear
regulator. The boost regulator provides power to the
linear regulator.
The boost regulator output voltage is regulated to 1.1V
above the LDO output, optimizing LDO ripple rejection and
transient response. Fixed frequency operation and current
mode control allow the use of very small inductors and
results in low, predictable output ripple.
The linear regulator in the LT3048 generates a program-
mable output and the LT3048-XX generate fixed output
voltages. High power supply ripple rejection combined
with a low noise internal reference results in less than
500µV
P-P
output ripple and noise.
The LT3048 is available in a 8-lead 2mm
×
2mm DFN
package.
L,
LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
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Generates Low Noise Bias Voltage from Single
Cell Li-Ion Battery
Output Current: Up to 40mA
Low Output Ripple and Noise: <500µV
P-P
Boost Regulator
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1MHz Operation (LT3048)
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2.2MHz Operation (LT3048-XX)
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Integrated Schottky Diode
Low Dropout Linear Regulator
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1.235V Feedback Voltage (LT3048)
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Low Noise: <120µV
RMS
(10Hz to 100kHz)
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0.1% Load Regulation
Fixed 3.3V, 5V, 12V, 15V and Adjustable Output Options
Short-Circuit and Thermal Protection
Load Disconnect in Shutdown
Available in 2mm
×
2mm DFN Package
APPLICATIONS
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Sensor Bias
Op Amp Supply
TYPICAL APPLICATION
Efficiency
IN
2.7V TO 4.8V
10µH
SW
1µF
V
IN
BSTOUT
LDOIN
EFFICIENCY (%)
LT3048-15
LDOOUT
OFF ON
EN
GND
3048 TA01a
80
4.7µF
70
60
50
40
30
20
10
0
0
5
10
LDOOUT = 15V
L = 10µH
DCR = 650m
V
IN
= 2.7V
V
IN
= 3.3V
V
IN
= 3.6V
20
15
LOAD CURRENT (mA)
25
3048 TA01b
BYP
1nF
1µF
OUT
15V
V
IN
(V) I
OUT
(mA)
2.7
19
3.3
22
3.6
24
3048fa
For more information
www.linear.com/LT3048
1
LT3048 Series
ABSOLUTE MAXIMUM RATINGS
(Note 1)
V
IN
..............................................................................6V
SW ............................................................................25V
BSTOUT ....................................................................23V
LDOIN .......................................................................22V
LDOOUT ....................................................................22V
FB ...............................................................................6V
BYP ........................................................................±0.3V
EN ...............................................................................6V
Operating Junction Temperature Range (Note 2)
E-Grade.............................................. –40°C to 125°C
I-Grade............................................... –40°C to 125°C
Maximum Junction Temperature .......................... 125°C
Storage Temperature Range .................. –65°C to 150°C
PIN CONFIGURATION
LT3048-XX
SW 1
V
IN
2
GND 3
BYP 4
9
GND
TOP VIEW
8 BSTOUT
7 EN
6 LDOIN
5 LDOOUT
LT3048
SW 1
V
IN
2
GND 3
BYP 4
9
GND
TOP VIEW
8 BSTOUT
7 EN
6 LDOOUT
5 FB
DC PACKAGE
8-LEAD (2mm
×
2mm) PLASTIC DFN
θ
JA
= 102°C/W
EXPOSED PAD (PIN 9) IS GND, MUST BE SOLDERED TO PCB
DC PACKAGE
8-LEAD (2mm
×
2mm) PLASTIC DFN
θ
JA
= 102°C/W
EXPOSED PAD (PIN 9) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
LT3048EDC#PBF
LT3048IDC#PBF
LT3048EDC-15#PBF
LT3048IDC-15#PBF
LT3048EDC-12#PBF
LT3048IDC-12#PBF
LT3048EDC-5#PBF
LT3048IDC-5#PBF
LT3048EDC-3.3#PBF
LT3048IDC-3.3t#PBF
TAPE AND REEL
LT3048EDC#TRPBF
LT3048IDC#TRPBF
LT3048EDC-15#TRPBF
LT3048IDC-15#TRPBF
LT3048EDC-12#TRPBF
LT3048IDC-12#TRPBF
LT3048EDC-5#TRPBF
LT3048IDC-5#TRPBF
LT3048EDC-3.3#TRPBF
LT3048IDC-3.3#TRPBF
PART MARKING
LGRR
LGRR
LGKK
LGKK
LGQQ
LGQQ
LGQR
LGQR
LGQS
LGQS
PACKAGE DESCRIPTION
8-Lead (2mm
×
2mm) Plastic DFN
8-Lead (2mm
×
2mm) Plastic DFN
8-Lead (2mm
×
2mm) Plastic DFN
8-Lead (2mm
×
2mm) Plastic DFN
8-Lead (2mm
×
2mm) Plastic DFN
8-Lead (2mm
×
2mm) Plastic DFN
8-Lead (2mm
×
2mm) Plastic DFN
8-Lead (2mm
×
2mm) Plastic DFN
8-Lead (2mm
×
2mm) Plastic DFN
8-Lead (2mm
×
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
–40°C to 125°C
–40°C to 125°C
–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 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
3048fa
For more information
www.linear.com/LT3048
LT3048 Series
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 3.6V, EN/UVLO = 3V, unless otherwise noted. Parameter applies
to all options unless specified.
PARAMETER
V
IN
Operating Range
Boost Regulator
BSTOUT-LDOOUT Regulation Voltage
BSTOUT-V
IN
Regulation Voltage
V
IN
Quiescent Current
Switching Frequency
LDOOUT < V
IN
Not Switching
EN ≤ 0.4V
LT3048
l
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ELECTRICAL CHARACTERISTICS
CONDITIONS
MIN
2.7
1
TYP
MAX
4.8
UNITS
V
V
V
µA
µA
MHz
MHz
MHz
MHz
%
%
1.1
1.1
475
0.1
1.2
600
1
1.25
1.30
2.7
2.8
0.75
0.7
1.7
1.6
93
86
300
1.00
1.00
2.2
2.2
95
90
400
220
0.84
LT3048-XX
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Maximum Duty Cycle
Switch Current Limit
Switch V
CESAT
Diode Forward Drop
EN Voltage High
EN Voltage Low
LDO Linear Regulator
LDO Quiescent Current
FB Pin Current
FB Regulation Voltage
FB Load Regulation
LDOOUT Regulation Voltage
LT3048
LT3048-XX
(Note 3)
I
SW
= 200mA
I
DIODE
= 100mA
500
mA
mV
V
V
1.25
0.4
LT3048: Supplied by LDOIN
LT3048-XX: Supplied by BSTOUT
LT3048: I
LOAD
= 100µA, FB = LDOOUT
LT3048: 100µA ≤ I
LOAD
≤ 40mA
LT3048: ∆I
LOAD
= 100µA to 40mA
LT3048-15: I
LOAD
= 100µA
LT3048-15: 100µA ≤ I
LOAD
≤ 40mA
LT3048-12: I
LOAD
= 100µA
LT3048-12: 100µA ≤ I
LOAD
≤ 40mA
LT3048-5: I
LOAD
= 100µA
LT3048-5: 100µA ≤ I
LOAD
≤ 40mA
LT3048-3.3: I
LOAD
= 100µA
LT3048-3.3: 100µA ≤ I
LOAD
≤ 40mA
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V
µA
µA
nA
V
V
mV
V
V
V
V
V
V
V
V
mV
mV
mV
mV
14
14
60
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20
20
1.254
1.260
6
15.225
15.375
12.18
12.30
5.075
5.125
3.350
3.383
45
45
25
18
1.216
1.210
14.775
14.625
11.82
11.70
4.925
4.875
3.250
3.217
1.235
1.235
2
15.00
15.00
12.00
12.00
5.00
5.00
3.300
3.300
20
20
12
9
LDOOUT Load Regulation
LT3048-15: ∆I
LOAD
= 100µA to 40mA
LT3048-12: ∆I
LOAD
= 100µA to 40mA
LT3048-5: ∆I
LOAD
= 100µA to 40mA
LT3048-3.3: ∆I
LOAD
= 100µA to 40mA
3048fa
For more information
www.linear.com/LT3048
3
LT3048 Series
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 3.6V, EN/UVLO = 3V, unless otherwise noted. Parameter applies
to all options unless specified.
PARAMETER
LDOOUT Voltage Noise
BW = 10Hz to 100kHz
C
OUT
= 1µF
CONDITIONS
LT3048: C
BYP
= 0nF, I
LOAD
= 40mA, LDOOUT = 1.235V
LT3048: C
BYP
= 1nF, I
LOAD
= 40mA, LDOOUT = 1.235V
LT3048-15: C
BYP
= 0nF, I
LOAD
= 24mA
LT3048-15: C
BYP
= 1nF, I
LOAD
= 24mA
LT3048-12: C
BYP
= 0nF, I
LOAD
= 31mA
LT3048-12: C
BYP
= 1nF, I
LOAD
= 31mA
LT3048-5: C
BYP
= 0nF, I
LOAD
= 40mA
LT3048:-5: C
BYP
= 1nF, I
LOAD
= 40mA
LT3048-3.3: C
BYP
= 0nF, I
LOAD
= 40mA
LT3048-3.3: C
BYP
= 1nF, I
LOAD
= 40mA
Ripple Rejection
Current Limit
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 LT3048E is 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. The
LT3048: f
RIPPLE
= 1.0MHz, I
LOAD
= 40mA
LT3048: f
RIPPLE
= 2.2MHz, I
LOAD
= 40mA
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ELECTRICAL CHARACTERISTICS
MIN
TYP
38
25
250
60
225
60
145
50
120
42
60
53
MAX
UNITS
µV
RMS
µV
RMS
µV
RMS
µV
RMS
µV
RMS
µV
RMS
µV
RMS
µV
RMS
µV
RMS
µV
RMS
dB
dB
mA
45
80
LT3048I is guaranteed over the full –40°C to 125°C operating junction
temperature range. High junction temperatures degrade operating
lifetimes. Operating lifetime is derated at junction temperatures greater
than 125°C.
Note 3:
Current limit guaranteed by design and/or correlation to static test.
Slope compensation reduces current limit at higher duty cycle.
4
3048fa
For more information
www.linear.com/LT3048
LT3048 Series
TYPICAL PERFORMANCE CHARACTERISTICS
LT3048 FB Voltage
1.260
1.255
1.250
FB VOLTAGE (V)
1.245
1.240
1.235
1.230
1.225
1.220
1.215
1.210
–50
–25
0
50
25
75
TEMPERATURE (°C)
100
125
1.260
1.255
1.250
FB VOLTAGE (V)
1.245
1.240
1.235
1.230
1.225
1.220
1.215
1.210
0
5
10 15 20 25 30
LOAD CURRENT (mA)
35
40
LT3048 FB Load Regulation
1.3
SWITCHING FREQUENCY (MHz)
1.2
1.1
1.0
0.9
0.8
LT3048 Switching Frequency
0.7
–50
–25
0
50
25
75
TEMPERATURE (°C)
100
125
3048 G01
3048 G02
3048 G03
LT3048 LDOOUT Noise
1000
NOISE SPECTRAL DENSITY (nV/√Hz)
80
70
100
EFFICIENCY (%)
LT3048-15 Efficiency
15.3
15.2
LDOOUT VOLTAGE (V)
15.1
15.0
14.9
14.8
14.7
LT3048-15 LDOOUT Load
Regulation
60
50
40
30
20
10
100k
1M
3048 G04
10
V
IN
= 3.6V
V
OUT
= 1.235V
L = 5.6 H
C
BSTOUT
= 4.7 F
C
LDOOUT
= 1 F
C
BYP
= 1nF
I
LOAD
= 40mA
10
100
1k
10k
FREQUENCY (Hz)
1
0.1
0.01
0
LDOOUT = 15V
L = 10µH
DCR = 650m
V
IN
= 2.7V
V
IN
= 3.3V
V
IN
= 3.6V
0
5
20
15
LOAD CURRENT (mA)
10
25
3048 G05
0
5
10 15 20 25 30
LOAD CURRENT (mA)
35
40
3048 G06
LT3048-15 LDOOUT Voltage
15.3
LT3048-15 Transient Response
50
OUTPUT VOLTAGE DEVIATION (mV)
0
–50
V
OUT
70
60
50
40
30
I
LOAD
20
10
3048 G08
LT3048-15 LDOOUT Noise
10000
NOISE SPECTRAL DENSITY (nV/√Hz)
15.2
LDOOUT VOLTAGE (V)
15.1
15.0
14.9
14.8
14.7
–50
1000
LOAD CURRENT (mA)
–100
–150
–200
–250
–300
100
V
IN
= 3.6V
V
OUT
= 15V
L = 10 H
C
BSTOUT
= 4.7 F
C
LDOOUT
= 1 F
C
BYP
= 1nF
I
LOAD
= 24mA
10
100
1k
10k
FREQUENCY (Hz)
100k
1M
3048 G09
10
1
–25
0
25
50
75
TEMPERATURE (°C)
100
125
3048 G07
V
IN
= 3.6V
10µs/DIV
V
OUT
= 15V
L = 10µH
C
LDOOUT
= 1µF
C
BYP
= 1nF
I
LOAD
= 4mA TO 20mA
0
0.1
3048fa
For more information
www.linear.com/LT3048
5
嵌入式系统
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