LT3467/LT3467A
1.1A Step-Up DC/DC
Converter with
Integrated Soft-Start
DESCRIPTION
FEATURES
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The LT®3467/LT3467A switching regulators combine a
42V, 1.1A switch with a soft-start function. Pin compatible
with the LT1930, its low VCESAT bipolar switch enables the
device to deliver high current outputs in a small footprint.
The LT3467 switches at 1.3MHz, allowing the use of tiny,
low cost and low height inductors and capacitors. The
LT3467A switches at 2.1MHz, allowing the use of even
smaller components. High inrush current at start-up is
eliminated using the programmable soft-start function.
A single external capacitor sets the current ramp rate. A
constant frequency current mode PWM architecture results
in low, predictable output noise that is easy to filter.
1.3MHz Switching Frequency (LT3467)
2.1MHz Switching Frequency (LT3467A)
Low VCESAT Switch: 330mV at 1.1A
High Output Voltage: Up to 40V
Wide Input Range: 2.4V to 16V
Dedicated Soft-Start Pin
5V at 540mA from 3.3V Input (LT3467)
5V at 430mA from 3.3V Input (LT3467A)
12V at 270mA from 5V Input (LT3467)
12V at 260mA from 5V Input (LT3467A)
Uses Small Surface Mount Components
Low Shutdown Current:
–
gmp
VOUT
+
CPL
+
VC
gma
RC
RO
CC
RESR
COUT
1.255V
REFERENCE
R1
–
R2
3467 F06
CC: COMPENSATION CAPACITOR
COUT: OUTPUT CAPACITOR
CPL: PHASE LEAD CAPACITOR
gma: TRANSCONDUCTANCE AMPLIFIER INSIDE IC
gmp: POWER STAGE TRANSCONDUCTANCE AMPLIFIER
RC: COMPENSATION RESISTOR
RL: OUTPUT RESISTANCE DEFINED AS VOUT DIVIDED BY ILOAD(MAX)
RO: OUTPUT RESISTANCE OF gma
R1, R2: FEEDBACK RESISTOR DIVIDER NETWORK
RESR: OUTPUT CAPACITOR ESR
1
2
Phase Lead Zero: Z4 =
RL
Phase Lead Pole: P4 =
fS
3
1
2 • π • R1• CPL
1
2 • π • CPL •
R1• R2
R1+ R2
The current mode zero is a right-half plane zero which can
be an issue in feedback control design, but is manageable
with proper external component selection.
Figure 6. Boost Converter Equivalent Model
3467afe
10
LT3467/LT3467A
APPLICATIONS INFORMATION
Table 3. Bode Plot Parameters
PARAMETER
VALUE
UNITS
COMMENT
RL
10.4
Ω
Application Specific
15
μF
Application Specific
50
0
COUT
40
–45
RESR
10
mΩ
Application Specific
30
–90
RO
0.4
MΩ
Not Adjustable
20
–135
CC
60
pF
Not Adjustable
10
–180
0
–225
–10
–270
–20
–315
–30
–360
–40
GAIN
PHASE
–50
100
1k
PHASE (DEG)
GAIN (dB)
Using the circuit of Figure 2 as an example, the following
table shows the parameters used to generate the Bode
plot shown in Figure 7.
–405
–450
1M
10k
100k
FREQUENCY (Hz)
3467 F07
Figure 7. Bode Plot of 3.3V to 5V Application
CPL
3.3
pF
Adjustable
RC
100
kΩ
Not Adjustable
R1
402
kΩ
Adjustable
R2
133
kΩ
VOUT
5
V
Application Specific
Adjustable
VIN
3.3
V
Application Specific
gma
35
μmho
Not Adjustable
gmp
7.5
mho
Not Adjustable
L
2.7
μH
fS
1.3*
MHz
Application Specific
Not Adjustable
*2.1MHz for LT3467A
From Figure 7, the phase is –138° when the gain reaches
0dB giving a phase margin of 42°. This is more than
adequate. The crossover frequency is 37kHz.
TYPICAL APPLICATIONS
Lithium-Ion to 6V Step-Up DC/DC Converter
L1
2.2μH
SW
VIN
C1
2.2μF
SHDN
C4
0.047μF
SHDN
LT3467
SS
95
D1
R1
501k
C3
1.8pF
VOUT
6V
275mA AT VIN = 2.7V
490mA AT VIN = 3.8V
590mA AT VIN = 4.2V
FB
GND
R2
133k
C2
15μF
90
VIN = 4.2V
85
EFFICIENCY (%)
VIN
2.7V TO 4.2V
Li-Ion to 6V
VIN = 3.8V
VIN = 2.7V
80
75
70
65
60
C1, C2: X5R OR X7R, 6.3V
D1: ON SEMICONDUCTOR MBRM120
L1: SUMIDA CR43-2R2
3467 TA02
55
50
50 100
200
300 400
IOUT (mA)
500
600
700
3467 TA02b
3467afe
11
LT3467/LT3467A
TYPICAL APPLICATIONS
4-Cell to 5V SEPIC Converter
C3
1μF
L1
10μH
4V TO 6.5V
C1
2.2μF
SHDN
4-CELL
BATTERY
D1
VIN
SW
SHDN
LT3467
FB
SS
255k
GND
84.5k
C4
0.047μF
VOUT
5V
325mA AT VIN = 4V
400mA AT VIN = 5V
450mA AT VIN = 6.5V
C5
4.7pF
L2
10μH
C2
10μF
D1: PHILIPS PMEG 2010
L1, L2: MURATA LQH32CN100K33L
C1, C3: X5R or X7R, 10V
C2: X5R or X7R, 6.3V
3467 TA03
5V to 40V Boost Converter
L1
2.7μH
VIN
5V
C1
4.7μF
SHDN
D1
SW
VIN
SHDN
LT3467
SS
C3
0.1μF
VOUT
40V
20mA
R1
412k
C2
1μF
FB
R2
13.3k
GND
C1: X5R or X7R, 6.3V
C2: X5R or X7R, 50V
D1: ON SEMICONDUCTOR, MBRM140
L1: SUMIDA CD43-2R7
3467 TA04a
±15V Dual Output Converter with Output Disconnect
VIN
5V
C4
1μF
L1
10μH
C1
2.2μF
OFF ON
SHDN
LT3467
SS
C6
0.047μF
15V
100mA
SW
VIN
D1
C5
1μF
R3
1Ω
R1
147k
D2
C2
2.2μF
FB
R2
13.3k
GND
C1: X5R or X7R, 6.3V
C2 TO C5: X5R or X7R, 16V
D1 TO D4: PHILIPS PMEG 2005
L1: SUMIDA CR43-100
D3 R4
1Ω
D4
C3
2.2μF
3467 TA05
–15V
100mA
3467afe
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LT3467/LT3467A
TYPICAL APPLICATIONS
9V, 18V, –9V Triple Output TFT-LCD Bias Supply with Soft-Start
D1
D2
C3
0.1μF
L1
4.7μH
VIN
3.3V
C1
2.2μF
VIN
9V
220mA
SW
3.3V
9V OUTPUT
5V/DIV
–9V OUTPUT
5V/DIV
R1
124k
C5
10μF
FB
SS
0V
Start-Up Waveforms
D5
SHDN
LT3467
VSHDN
18V
10mA
C4
1μF
GND
C2
0.1μF
C7
0.1μF
C1: X5R OR X7R, 6.3V
C2,C3, C5, C6: X5R OR X7R, 10V
C4: X5R OR X7R, 25V
D1 TO D4: PHILIPS BAT54S OR EQUIVALENT
D5: PHILIPS PMEG 2005
L1: PANASONIC ELT5KT4R7M
R2
20k
18V OUTPUT
10V/DIV
IL1
0.5A/DIV
D4
D3
C6
1μF
–9V
10mA
2ms/DIV
3467 TA06b
3467 TA06a
8V, 23V, –8V Triple Output TFT-LCD Bias Supply with Soft-Start
D1
D2
D3
C3
0.1μF
L1
4.7μH
VIN
3.3V
C1
2.2μF
SHDN
LT3467
SS
VSHDN
3.3V
0V
C4
0.1μF
C5
0.1μF
23V
10mA
C6
1μF
Start-Up Waveforms
D7
8V
270mA
R1
113k
SW
VIN
D4
C7
10μF
FB
GND
C9
0.1μF
C1: X5R OR X7R, 6.3V
C2 TO C4, C7, C8: X5R OR X7R, 10V
C5: X5R OR X7R, 16V
C6: X5R OR X7R, 25V
D1 TO D6: PHILIPS BAT54S OR EQUIVALENT
D7: PHILIPS PMEG 2005
L1: PANASONIC ELT5KT4R7M
8V OUTPUT
5V/DIV
–8V OUTPUT
5V/DIV
C2
0.1μF
R2
21k
23V OUTPUT
10V/DIV
IL1
0.5A/DIV
D5
D6
C8
1μF
3467 TA07a
2ms/DIV
3467 TA07b
–8V
10mA
3467afe
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LT3467/LT3467A
TYPICAL APPLICATIONS
Single Li-Ion Cell to 5V Boost Converter
L1
0.9μH
SW
VIN
C1
4.7μF
95
D1
R1
8.06k
C4*
75pF
SHDN
LT3467A
SS
FB
OFF ON
C3
0.047μF
VOUT
5V
600mA AT VIN = 4.2V
360mA AT VIN = 3.3V
250mA AT VIN = 2.6V
C2*
22μF
R2
2.67k
GND
90
85
EFFICIENCY (%)
VIN
2.6V TO 4.2V
Efficiency
80
VIN = 3.3V
VIN = 4.2V
VIN = 2.6V
75
70
65
60
C1, C2: X5R OR X7R, 6.3V
D1: PHILIPS PMEG 2010
L1: FDK MIPW3226D0R9M
*C2 CAN BE 10μF IN A 1210 OR LARGER PACKAGE WITH
THE ADDITION OF C4, OTHERWISE C4 IS OPTIONAL
3467 TA09a
55
50
50 100 150 200 250 300 350 400 450 500
IOUT (mA)
3467 TA09b
2.6V-3.3V to 5V Boost Converter
L1
1.5μH
SW
VIN
C1
4.7μF
OFF ON
90
D1
VOUT
5V
430mA AT VIN = 3.3V
270mA AT VIN = 2.6V
R1
8.06k
C4
56pF
SHDN
LT3467A
SS
FB
C3
0.047μF
C2
10μF
R2
2.67k
GND
85
80
EFFICIENCY (%)
VIN
2.6V TO 3.3V
Efficiency
VIN = 2.6V
75
VIN = 3.3V
70
65
60
C1, C2: X5R OR X7R, 6.3V
D1: PHILIPS PMEG 2010
L1: FDK MIP3226D1R5M
3467 TA08a
55
50
50 100 150 200 250 300 350 400 450 500
IOUT (mA)
3467 TA08b
3.3V to 15V, 135mA Step-Up Converter
VIN
C1
4.7μF
OFF ON
C3
0.047μF
SW
C1: X5R OR X7R, 6.3V
C2: X5R OR X7R, 16V
D1: PHILIPS PMEG 2010
L1: SUMIDA CMD4D13-6R8MC
VOUT
15V
135mA
R1
16.5k
SHDN
LT3467A
SS
FB
GND
90
D1
C4
68pF
R2
1.5k
C2
2.2μF
3467 TA10a
80
EFFICIENCY (%)
L1
6.8μH
VIN
3.3V
Efficiency
70
60
50
40
30
20
40
60
80 100
IOUT (mA)
120
140
160
3467 TA10b
3467afe
14
LT3467/LT3467A
PACKAGE DESCRIPTION
DDB Package
8-Lead Plastic DFN (3mm × 2mm)
(Reference LTC DWG # 05-08-1702 Rev B)
0.61 p0.05
(2 SIDES)
3.00 p0.10
(2 SIDES)
R = 0.115
TYP
5
R = 0.05
TYP
0.40 p 0.10
8
0.70 p0.05
2.55 p0.05
1.15 p0.05
PACKAGE
OUTLINE
0.25 p 0.05
0.50 BSC
2.20 p0.05
(2 SIDES)
PIN 1 BAR
TOP MARK
(SEE NOTE 6)
0.200 REF
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
2.00 p0.10
(2 SIDES)
0.56 p 0.05
(2 SIDES)
0.75 p0.05
0 – 0.05
4
0.25 p 0.05
1
PIN 1
R = 0.20 OR
0.25 s 45o
CHAMFER
(DDB8) DFN 0905 REV B
0.50 BSC
2.15 p0.05
(2 SIDES)
BOTTOM VIEW—EXPOSED PAD
NOTE:
1. DRAWING CONFORMS TO VERSION (WECD-1) IN JEDEC PACKAGE OUTLINE M0-229
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
3467afe
15
LT3467/LT3467A
PACKAGE DESCRIPTION
S6 Package
6-Lead Plastic TSOT-23
(Reference LTC DWG # 05-08-1636)
0.62
MAX
2.90 BSC
(NOTE 4)
0.95
REF
1.22 REF
3.85 MAX 2.62 REF
1.4 MIN
2.80 BSC
1.50 – 1.75
(NOTE 4)
PIN ONE ID
RECOMMENDED SOLDER PAD LAYOUT
PER IPC CALCULATOR
0.30 – 0.45
6 PLCS (NOTE 3)
0.95 BSC
0.80 – 0.90
0.20 BSC
0.01 – 0.10
1.00 MAX
DATUM ‘A’
0.30 – 0.50 REF
0.09 – 0.20
(NOTE 3)
NOTE:
1. DIMENSIONS ARE IN MILLIMETERS
2. DRAWING NOT TO SCALE
3. DIMENSIONS ARE INCLUSIVE OF PLATING
4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR
5. MOLD FLASH SHALL NOT EXCEED 0.254mm
6. JEDEC PACKAGE REFERENCE IS MO-193
1.90 BSC
S6 TSOT-23 1005
3467afe
16
LT3467/LT3467A
REVISION HISTORY
(Revision history begins at Rev E)
REV
DATE
DESCRIPTION
PAGE NUMBER
E
04/10
Updated Note 2 in Absolute Maximum Ratings and Electrical Characteristics
2, 3
3467afe
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.
17
LT3467/LT3467A
TYPICAL APPLICATIONS
L1
4.7μH
C1
2.2μF
VIN
SHDN
VOUT
12V
270mA
R1
115k
SW
SHDN
LT3467
SS
C3
0.047μF
Efficiency
D1
C4*
22pF
FB
C1: X5R OR X7R, 6.3V
C2: X5R OR X7R, 16V
D1: PHILIPS PMEG 2010
L1: SUMIDA CR43-4R7
*OPTIONAL
85
80
C2
10μF
R2
13.3k
GND
90
EFFICIENCY (%)
VIN
5V
75
70
65
60
3467 F08a
55
50
Figure 8. 5V to 12V, 270mA Step-Up Converter
VIN
OFF ON
C3
0.047μF
D1
SW
VOUT
12V
260mA
R1
115k
200
250
IOUT (mA)
300
350
3467 F08b
90
85
SHDN
LT3467A
SS
FB
GND
150
95
C4
12pF
C2
10μF
R2
13.3k
C1: X5R OR X7R, 6.3V
C2: X5R OR X7R, 16V
D1: PHILIPS PMEG 2010
L1: SUMIDA CDRH4D18-3R3
3467 F09a
EFFICIENCY (%)
C1
4.7μF
100
Efficiency
L1
3.3μH
VIN
5V
50
80
75
70
65
60
55
Figure 9. 5V to 12V, 260mA Step-Up Converter
50
50
100
150
200
IOUT (mA)
250
300
3467 F09b
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DESCRIPTION
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LT1930/LT1930A
LT1946/LT1946A
LT1961
LTC3400/
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600mA (ISW), 1.2MHz, Synchronous Step-Up DC/DC Converter
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2A (ISW), 3MHz, Synchronous Step-Up DC/DC Converter
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No RSENSE is a trademark of Linear Technology Corporation.
LT3464
COMMENTS
VIN: 1V to 15V, VOUT(MAX) = 34V, IQ = 20μA, ISD < 1μA,
ThinSOT Package
90% Efficiency, VIN: 1.6V to 18V, VOUT(MAX) = 35V, IQ = 1.8mA,
ISD < 1μA, MS Package
95% Efficiency, VIN: 0.9V to 5V, IQ = 200μA, ISD < 10μA,
MS Package
92% Efficiency, VIN: 2.5V to 36V, IQ = 250μA, ISD < 10μA,
MS Package
High Efficiency, VIN: 2.6V to 16V, VOUT(MAX) = 34V,
IQ = 4.2mA/5.5mA, ISD < 1μA, ThinSOT Package
High Efficiency, VIN: 2.45V to 16V, VOUT(MAX) = 34V, IQ = 3.2mA,
ISD < 1μA, MS8 Package
90% Efficiency, VIN: 3V to 25V, VOUT(MAX) = 35V, IQ = 0.9mA,
ISD < 6μA, MS8E Package
92% Efficiency, VIN: 0.85V to 5V, VOUT(MAX) = 5V,
IQ = 19μA/300μA, ISD < 1μA, ThinSOT Package
97% Efficiency, VIN: 0.5V to 5V, VOUT(MAX) = 5.5V, IQ = 38μA,
ISD < 1μA, MS Package
97% Efficiency, VIN: 0.5V to 5V, VOUT(MAX) = 5.5V, IQ = 38μA,
ISD < 1μA, MS Package
VIN: 2.3V to 10V, VOUT(MAX) = 34V, IQ = 25μA, ISD < 1μA,
ThinSOT Package
3467afe
18 Linear Technology Corporation
LT 0410 REV E • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507
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