LT3467IS5 [Linear]
IC 2.5 A SWITCHING REGULATOR, 1600 kHz SWITCHING FREQ-MAX, PDSO6, 1 MM HEIGHT, PLASTIC, MO-193, TSOT-23, 6 PIN, Switching Regulator or Controller;
| 型号： | LT3467IS5 |
| 厂家： | 
Linear |
| 描述： | IC 2.5 A SWITCHING REGULATOR, 1600 kHz SWITCHING FREQ-MAX, PDSO6, 1 MM HEIGHT, PLASTIC, MO-193, TSOT-23, 6 PIN, Switching Regulator or Controller 开关 光电二极管 |
| 文件： | 总16页 (文件大小：246K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
LT3467/LT3467A
1.1A Step-Up DC/DC
Converter with
Integrated Soft-Start
U
FEATURES
DESCRIPTIO
The LT®3467/LT3467A switching regulators combine a
42V, 1.1Aswitchwithasoft-startfunction. Pincompatible
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 re-
sults 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: <1μA
■
Pin-for-Pin Compatible with the LT1930 and LT1613
The high voltage switch on the LT3467/LT3467A is rated
at 42V, making the devices ideal for boost converters up
to 40V as well as SEPIC and flyback designs. The LT3467
can generate 5V at up to 540mA from a 3.3V supply or 5V
at 450mA from four alkaline cells in a SEPIC design. The
LT3467A can generate 5V at up to 430mA from a 3.3V
supply or 15V at 135mA from a 3.3V supply. The LT3467/
LT3467A are available in a low profile (1mm) 6-lead
SOT-23 package and tiny 3mm x 2mm DFN package.
Low Profile (1mm) ThinSOT™ Package
■
■
Low Profile (0.75mm) 8-Lead (3mm x 2mm)
DFN Package
U
APPLICATIO S
■
Digital Cameras
White LED Power Supplies
Cellular Phones
Medical Diagnostic Equipment
Local 5V or 12V Supplies
TFT-LCD Bias Supplies
xDSL Power Supplies
■
■
■
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
ThinSOT is a trademark of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
■
■
■
U
Efficiency
TYPICAL APPLICATIO
95
90
Single Li-Ion Cell to 5V Boost Converter
V
= 4.2V
IN
= 3.3V
85
80
75
70
65
60
55
50
2.7μH
V
IN
V
V
IN
OUT
5V
765mA AT V = 4.2V,
2.6V TO
4.2V
V
= 2.6V
IN
IN
4.7μF
402k
133k
540mA AT V = 3.3V,
IN
360mA AT V = 2.6V
V
SW
IN
IN
3.3pF
SHDN
OFF ON
LT3467
GND
SS
FB
15μF
0.047μF
3467 TA01a
800
900
100
300 400 500
700
200
600
I
(mA)
OUT
3467 TA01b
3467afc
1
LT3467/LT3467A
W W
U W
ABSOLUTE AXI U RATI GS
(Note 1)
VIN Voltage .............................................................. 16V
SW Voltage ................................................–0.4V to 42V
FB Voltage .............................................................. 2.5V
Current Into FB Pin .............................................. 1mA
SHDN Voltage ......................................................... 16V
Maximum Junction Temperature ......................... 125°C
Operating Temperature Range (Note 2)
E Grade ................................................. –40°C to 85°C
I Grade................................................ –40°C to 125°C
Storage Temperature Range ................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec,
TSOT Only) ........................................................... 300°C
U
U
U
PI CO FIGURATIO
TOP VIEW
TOP VIEW
SW 1
GND 2
FB 3
6 V
IN
FB
GND
SW
1
2
3
4
8
7
6
5
SHDN
SS
5 SS
9
4 SHDN
VIN
SW
GND
S6 PACKAGE
6-LEAD PLASTIC TSOT-23
DDB PACKAGE
8-LEAD (3mm × 2mm) PLASTIC DFN
TJMAX = 125°C, θJA = 165°C/ W, θJC = 102°C/ W
TJMAX = 125°C, θJA = 80°C/ W
EXPOSED PAD (PIN 9) IS GROUND
(MUST BE SOLDERED TO PCB)
U
W
U
ORDER I FOR ATIO
LEAD FREE FINISH
LT3467EDDB#PBF
LT3467AEDDB#PBF
LT3467IS6#PBF
LT3467ES6#PBF
LT3467AES6#PBF
LEAD BASED FINISH
LT3467EDDB
TAPE AND REEL
PART MARKING*
LCPX
PACKAGE DESCRIPTION
TEMPERATURE RANGE
–40°C to 85°C
–40°C to 85°C
–40°C to 125°C
–40°C to 85°C
LT3467EDDB#TRPBF
LT3467AEDDB#TRPBF
LT3467IS6#TRPBF
LT3467ES6#TRPBF
LT3467AES6#TRPBF
TAPE AND REEL
8-Lead (3mm × 2mm) Plastic DFN
8-Lead (3mm × 2mm) Plastic DFN
6-Lead Plastic TSOP-23
LCKD
LTACH
LTACH
6-Lead Plastic TSOP-23
LTBCC
6-Lead Plastic TSOP-23
–40°C to 85°C
PART MARKING*
LCPX
PACKAGE DESCRIPTION
TEMPERATURE RANGE
–40°C to 85°C
–40°C to 85°C
–40°C to 125°C
–40°C to 85°C
LT3467EDDB#TR
LT3467AEDDB#TR
LT3467IS6#TR
8-Lead (3mm × 2mm) Plastic DFN
8-Lead (3mm × 2mm) Plastic DFN
6-Lead Plastic TSOP-23
LT3467AEDDB
LT3467IS5
LCKD
LTACH
LTACH
LT3467ES6
LT3467ES6#TR
6-Lead Plastic TSOP-23
LT3467AES67
LT3467AES6#TR
LTBCC
6-Lead Plastic TSOP-23
–40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
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/
3467afc
2
LT3467/LT3467A
ELECTRICAL CHARACTERISTICS
The ● denotes specifications which apply over the full operating
temperature range, otherwise specifications are TA = 25°C. VIN = 3V, VSHDN = VIN unless otherwise noted. Specifications are for both
the LT3467 and LT3467A unless otherwise noted.
PARAMETER
CONDITIONS
MIN
TYP
MAX
2.4
UNITS
Minimum Operating Voltage
Maximum Operating Voltage
Feedback Voltage
2.2
V
V
16
1.230
1.220
1.255
1.270
1.280
V
V
●
●
FB Pin Bias Current
(Note 3)
10
50
2
nA
mA
μA
Quiescent Current
V
V
= 2.4V, Not Switching
1.2
SHDN
SHDN
Quiescent Current in Shutdown
Reference Line Regulation
Switching Frequency
= 0.5V, V = 3V
0.01
0.01
1
IN
2.6V ≤ V ≤ 16V
0.05
%/V
IN
LT3467
LT3467A
LT3467A
1
1.6
1.6
1.3
2.1
1.6
2.7
MHz
MHz
MHz
●
Maximum Duty Cycle
LT3467
LT3467
LT3467A
LT3467A
88
87
82
78
94
88
%
%
%
%
●
●
Minimum Duty Cycle
Switch Current Limit
10
%
At Minimum Duty Cycle
At Maximum Duty Cycle (Note 4)
1.4
0.8
1.8
1.2
2.5
1.9
A
A
Switch V
I
= 1.1A
= 5V
330
500
1
mV
μA
V
CESAT
SW
Switch Leakage Current
SHDN Input Voltage High
SHDN Input Voltage Low
SHDN Pin Bias Current
V
0.01
SW
2.4
0.5
V
V
V
= 3V
16
0
32
0.1
μA
μA
SHDN
SHDN
= 0V
SS Charging Current
V
= 0.5V
2
3
4.5
μA
SS
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.
operating temperature range are assured by design, characterization and
correlation with statistical process controls. LT3467IS6 is guaranteed and
tested over the full –40°C to 125°C operating temperature range.
Note 3: Current flows out of the pin.
Note 2: The LT3467E/LT3467AE are guaranteed to meet performance
specifications from 0°C to 85°C. Specifications over the –40°C to 85°C
Note 4: See Typical Performance Characteristics for guaranteed current
limit vs duty cycle.
3467afc
3
LT3467/LT3467A
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Quiescent Current vs
Temperature
FB Pin Voltage vs Temperature
SHDN Current vs SHDN Voltage
1.26
1.25
1.24
1.23
1.22
1.21
1.20
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
140
120
100
80
T
= 25°C
A
60
40
20
0
–25 –10 5 20 35 50 65 80 125
95 110
–25 –10
5
20 35 50 65 80
125
95 110
–40
–40
0
2
4
6
12 14 16 18
8
10
TEMPERATURE (°C)
TEMPERATURE (°C)
V
(V)
SHDN
3467 G03
3467 G02
3467 G01
Oscillator Frequency vs
Temperature
Switch Saturation Voltage vs
Switch Current
Current Limit vs Duty Cycle
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
2.50
2.25
2.00
1.75
1.50
1.25
1.00
0.75
0.50
0.25
0
T
= 25°C
A
LT3467A
TYPICAL
T
= 25°C
A
T
= 85°C
A
V
CESAT
LT3467
GUARANTEED
100mV
/DIV
T
= –40°C
A
3467 G05
–25
0
25
50
75
10
50
70 80
–50
100
20 30 40
60
90
SW CURRENT 200mA/DIV
DC (%)
TEMPERATURE (°C)
3467 G04
3467 G06
Soft-Start Current vs Soft-Start
Voltage
Peak Switch Current vs Soft-Start
Voltage
Start-Up Waveform
(Figure 2 Circuit)
6
5
4
3
2
1
0
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
T
= 25°C
T = 25°C
A
A
V
SHDN
2V/DIV
V
OUT
1V/DIV
I
SUPPLY
0.5A/DIV
3467 G09
0
50 100 150 200 250 300 350 400 450 500
(mV)
0.5ms/DIV
0
50 100 150 200 250 300 350 400 450 500
(mV)
V
V
SS
SS
3467 G07
3467 G08
3467afc
4
LT3467/LT3467A
U
U
U
PI FU CTIO S
(DFN/TSOT)
FB (Pin 1/Pin 3): Feedback Pin. Reference voltage is
1.255V. Connect resistive divider tap here. Minimize trace
area at FB. Set VOUT = 1.255V(1 + R1/R2).
VIN (Pin 6/Pin 6): Input Supply Pin. Must be locally
bypassed.
SS (Pin 7/Pin 5): Soft-Start Pin. Place a soft-start capaci-
torhere.Uponstart-up,4μAofcurrentchargesthecapaci-
tor to 1.255V. Use a larger capacitor for slower start-up.
Leave floating if not in use.
GND (Pins 2, 5, 9/Pin 2): Ground. Tie directly to local
ground plane.
SW (Pins 3, 4/Pin 1): Switch Pin. (Collector of internal
NPN power switch) Connect inductor/diode here and
minimize the metal trace area connected to this pin to
minimize EMI.
SHDN (Pin 8/Pin 4): Shutdown Pin. Tie to 2.4V or more to
enable device. Ground to shut down.
W
BLOCK DIAGRA
250k
SS
SW
1.255V
V
IN
+
–
COMPARATOR
REFERENCE
–
A1
DRIVER
Q1
A2
R
Q
R
C
S
+
V
OUT
R1 (EXTERNAL)
C
C
+
–
0.01Ω
Σ
FB
R2 (EXTERNAL)
RAMP
GENERATOR
SHUTDOWN
SHDN
FB
GND
3467 F01
1.3MHz
OSCILLATOR*
*2.1MHz FOR LT3467A
Figure 1. Block Diagram
3467afc
5
LT3467/LT3467A
U
OPERATIO
The LT3467 uses a constant frequency, current-mode
control scheme to provide excellent line and load regula-
tion. Refer to the Block Diagram above. At the start of each
oscillator cycle, the SR latch is set which turns on the
power switch Q1. A voltage proportional to the switch
current is added to a stabilizing ramp and the resulting
sum is fed into the positive terminal of the PWM compara-
tor A2. When this voltage exceeds the level at the negative
input of A2, the SR latch is reset, turning off the power
switch. The level at the negative input of A2 is set by the
erroramplifierA1,andissimplyanamplifiedversionofthe
difference between the feedback voltage and the reference
voltage of 1.255V. In this manner, the error amplifier sets
the correct peak current level to keep the output in regu-
lation. If the error amplifier’s output increases, more
current is delivered to the output. Similarly, if the error
decreases, less current is delivered. The soft-start feature
of the LT3467 allows for clean start-up conditions by
limiting the rate of voltage rise at the output of comparator
A1 which, in turn, limits the peak switch current. The soft-
start pin is connected to a reference voltage of 1.255V
through a 250k resistor, providing 4μA of current to
charge the soft-start capacitor. Typical values for the soft-
start capacitor range from 10nF to 200nF. The LT3467 has
a current limit circuit not shown in the Block Diagram. The
switch current is constantly monitored and not allowed to
exceedthemaximumswitchcurrent(typically1.4A). Ifthe
switch current reaches this value, the SR latch is reset
regardlessofthestateofcomparatorA2. Thiscurrentlimit
protects the power switch as well as the external compo-
nents connected to the LT3467.
The Block Diagram for the LT3467A (not shown) is
identical except that the oscillator frequency is 2.1MHz.
U
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APPLICATIONS INFORMATION
Switching Frequency and Inductor Selection
Duty Cycle
TheLT3467switchesat1.3MHz,allowingforsmallvalued
inductors to be used. 4.7μH or 10μH will usually suffice.
The LT3467A switches at 2.1MHz, allowing for even
smaller valued inductors to be used. 0.9μH to 6.8μH will
usuallysuffice. Chooseaninductorthatcanhandleatleast
1.2A without saturating, and ensure that the inductor has
alowDCR(copper-wireresistance)tominimizeI2Rpower
losses. Note that in some applications, the current han-
dling requirements of the inductor can be lower, such as
in the SEPIC topology where each inductor only carries
one half of the total switch current. For better efficiency,
use similar valued inductors with a larger volume. Many
different sizes and shapes are available from various
manufacturers.Chooseacorematerialthathaslowlosses
at1.3MHz, (2.1MHzfortheLT3467A)suchasferritecore.
The typical maximum duty cycle of the LT3467 is 94%
(88% for the LT3467A). The duty cycle for a given
application is given by:
| VOUT | + | VD | – | V |
| VOUT | + | VD | – | VCESAT
IN
DC =
|
Where VD is the diode forward voltage drop and VCESAT
is in the worst case 330mV (at 1.1A)
The LT3467 and LT3467A can be used at higher duty
cycles,butmustbeoperatedinthediscontinuousconduc-
tion mode so that the actual duty cycle is reduced.
Setting Output Voltage
R1 and R2 determine the output voltage.
V
OUT = 1.255V (1+ R1/R2)
3467afc
6
LT3467/LT3467A
U
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APPLICATIONS INFORMATION
L1
2.7μH
D1
V
IN
V
OUT
2.6V TO
4.2V
5V
765mA AT V = 4.2V,
C1
R1
402k
IN
IN
IN
4.7μF
540mA AT V = 3.3V,
360mA AT V = 2.6V
V
SW
IN
C4
3.3pF
SHDN
OFF ON
LT3467
SS
FB
C2
R2
133k
C3
GND
15μF
0.047μF
C1, C2: X5R OR X7R, 6.3V
3467 TA05a
D1: ON SEMICONDUCTOR MBRM120
L1: SUMIDA CR43-2R7
Supply Current of Figure 2 During
Startup without Soft-Start Capacitor
Figure 2. Single Li-Ion Cell to 5V Boost Converter
(Same as 1st Page Application)
VOUT
1V/DIV
Table 1. Inductor Manufacturers.
Sumida
TDK
(847) 956-0666
(847) 803-6100
(714) 852-2001
(408) 432-8331
www.sumida.com
www.tdk.com
Murata
FDK
www.murata.com
www.fdk.co.jp
ISUPPLY
0.5A/DIV
0.1ms/DIV
Soft-Start
The soft-start feature provides a way to limit the inrush
current drawn from the supply upon startup. An internal
250k resistor charges the external soft start capacitor to
1.255V. After the capacitor reaches 0.15V the rate of
voltage rise at the output of the comparator A1 tracks the
rate of voltage rise of the soft-start capacitor. This limits
the inrush current drawn from the supply during startup.
Once the part is shut down, the soft start capacitor is
quicklydischargedto0.4V,thenslowlydischargedthrough
the 250k resistor to ground. If the part is to be shut down
and re-enabled in a short period of time while soft-start is
used, you must ensure that the soft-start capacitor has
enough time to discharge before re-enabling the part.
Typical values of the soft-start capacitor range from 10nF
to 200nF.
Supply Current of Figure 2 During
Startup with 47nF Soft-Start Capacitor
VOUT
1V/DIV
ISUPPLY
0.5A/DIV
0.5ms/DIV
3467afc
7
LT3467/LT3467A
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APPLICATIONS INFORMATION
A phase lead zero can be intentionally introduced by
placing a capacitor (C4) in parallel with the resistor (R1)
betweenVOUT andVFB asshowninFigure2.Thefrequency
of the zero is determined by the following equation.
CAPACITOR SELECTION
Low ESR (equivalent series resistance) capacitors should
beusedattheoutputtominimizetheoutputripplevoltage.
Multi-layer ceramic capacitors are an excellent choice, as
they have extremely low ESR and are available in very
small packages. X5R dielectrics are preferred, followed by
X7R, as these materials retain the capacitance over wide
voltage and temperature ranges. A 4.7μF to 15μF output
capacitor is sufficient for most applications, but systems
withverylowoutputcurrentsmayneedonlya1μFor2.2μF
outputcapacitor. SolidtantalumorOSCONcapacitorscan
be used, but they will occupy more board area than a
ceramicandwillhaveahigherESR.Alwaysuseacapacitor
with a sufficient voltage rating.
1
ƒZ =
2π •R1• C4
By choosing the appropriate values for the resistor and
capacitor, the zero frequency can be designed to improve
the phase margin of the overall converter. The typical
target value for the zero frequency is between 35kHz to
55kHz. Figure 3 shows the transient response of the step-
up converter from Figure 8 without the phase lead capaci-
tor C4. Although adequate for many applications, phase
margin is not ideal as evidenced by 2-3 “bumps” in both
the output voltage and inductor current. A 22pF capacitor
for C4 results in ideal phase margin, which is revealed in
Figure 4 as a more damped response and less overshoot.
Ceramic capacitors also make a good choice for the input
decoupling capacitor, which should be placed as close as
possible to the LT3467. A 1μF to 4.7μF input capacitor is
sufficient for most applications. Table 2 shows a list of
several ceramic capacitor manufacturers. Consult the
manufacturers for detailed information on their entire
selection of ceramic parts.
DIODE SELECTION
ASchottkydiodeisrecommendedforusewiththeLT3467
and the LT3467A. The Philips PMEG 2005 is a very good
choice. Where the switch voltage exceeds 20V, use the
PMEG 3005 (a 30V diode). Where the switch voltage
exceeds 30V, use the PMEG 4005 (a 40V diode). These
diodes are rated to handle an average forward current of
0.5A. In applications where the average forward current of
the diode exceeds 0.5A, a Philips PMEG 2010 rated at 1A
is recommended. For higher efficiency, use a diode with
better thermal characteristics such as the On Semicon-
ductor MBRM120 (a 20V diode) or the MBRM140 (a 40V
diode).
Table 2. Ceramic Capacitor Manufacturers
Taiyo Yuden
AVX
(408) 573-4150
(803) 448-9411
(714) 852-2001
www.t-yuden.com
www.avxcorp.com
www.murata.com
Murata
ThedecisiontouseeitherlowESR(ceramic)capacitorsor
the higher ESR (tantalum or OSCON) capacitors can affect
the stability of the overall system. The ESR of any capaci-
tor, along with the capacitance itself, contributes a zero to
the system. For the tantalum and OSCON capacitors, this
zero is located at a lower frequency due to the higher value
of the ESR, while the zero of a ceramic capacitor is at a
much higher frequency and can generally be ignored.
3467afc
8
LT3467/LT3467A
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APPLICATIONS INFORMATION
LAYOUT HINTS
The high speed operation of the LT3467/LT3467A de-
mands careful attention to board layout. You will not get
advertised performance with careless layout. Figure 5A
shows the recommended component placement for the
ThinSOT package. Figure 5B shows the recommended
component placement for the DFN package. Note the
VIA’s under the exposed PAD. These should connect to a
local ground plane for better thermal performance.
LOAD CURRENT
100mA/DIV
AC COUPLED
VOUT
200mV/DIV
AC COUPLED
IL1
5A/DIV
AC COUPLED
20μs/DIV
3467 F03
Figure 3. Transient Response of Figure 8's Step-Up
Converter without Phase Lead Capacitor
LOAD CURRENT
100mA/DIV
AC COUPLED
VOUT
200mV/DIV
AC COUPLED
IL1
5A/DIV
AC COUPLED
Figure 5A.
Suggested Layout—ThinSOT
20μs/DIV
3467 F04
Figure 4. Transient Response of Figure 8's Step-Up
Converter with 22pF Phase Lead Capacitor
SETTING OUTPUT VOLTAGE
To set the output voltage, select the values of R1 and R2
(see Figure 2) according to the following equation.
VOUT
1.255V
⎛
⎞
⎠
R1= R2
– 1
⎜
⎝
⎟
A good value for R2 is 13.3k which sets the current in the
resistor divider chain to 1.255V/13.3k = 94μA.
3467afc
9
LT3467/LT3467A
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APPLICATIONS INFORMATION
Compensation—Theory
From Figure 6, the DC gain, poles and zeroes can be
calculated as follows:
Like all other current mode switching regulators, the
LT3467/LT3467A needs to be compensated for stable and
efficient operation. Two feedback loops are used in the
LT3467/LT3467A: a fast current loop which does not
require compensation, and a slower voltage loop which
does. Standard Bode plot analysis can be used to under-
stand and adjust the voltage feedback loop.
2
Output Pole: P1=
2 • π •RL • COUT
1
Error Amp Pole: P2=
2 • π •RO • CC
1
Error Amp Zero: Z1=
2 • π •RC • CC
As with any feedback loop, identifying the gain and phase
contribution of the various elements in the loop is critical.
Figure 6 shows the key equivalent elements of a boost
converter. Because of the fast current control loop, the
power stage of the IC, inductor and diode have been
1.255
1
2
DC GAIN: A=
• V • gma •RO • gmp •RL •
IN
2
VOUT
1
ESR Zero: Z2 =
replaced by the equivalent transconductance amplifier g
.
mp
2 • π •RESR • COUT
g
acts as a current source where the output current is
mp
2 •RL
proportional to the V voltage. Note that the maximum output
V
C
IN
RHP Zero: Z3=
current of g is finite due to the current limit in the IC.
2 • π • VOUT2 •L
mp
fS
3
High Frequency Pole: P3>
–
1
g
mp
V
OUT
Phase Lead Zero : Z4 =
+
C
R
R
L
2 • π •R1• CPL
PL
ESR
C
OUT
1
1.255V
REFERENCE
+
–
Phase Lead Pole :P4 =
V
C
R1•R2
R1+ R2
g
ma
R1
R2
2 • π • CPL
•
R
R
O
C
C
C
3467 F06
C : COMPENSATION CAPACITOR
C
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.
C
C
: OUTPUT CAPACITOR
OUT
: PHASE LEAD CAPACITOR
PL
ma
mp
g
g
: TRANSCONDUCTANCE AMPLIFIER INSIDE IC
: POWER STAGE TRANSCONDUCTANCE AMPLIFIER
R : COMPENSATION RESISTOR
C
L
R : OUTPUT RESISTANCE DEFINED AS V
R : OUTPUT RESISTANCE OF g
DIVIDED BY I
LOAD(MAX)
OUT
O
ma
R1, R2: FEEDBACK RESISTOR DIVIDER NETWORK
: OUTPUT CAPACITOR ESR
R
ESR
Figure 6. Boost Converter Equivalent Model
3467afc
10
LT3467/LT3467A
U
W U U
APPLICATIONS INFORMATION
Table 3. Bode Plot Parameters
Using the circuit of Figure 2 as an example, the following
tableshowstheparametersusedtogeneratetheBodeplot
shown in Figure 7.
Parameter
Value
10.4
15
Units
Ω
Comment
R
L
Application Specific
Application Specific
Application Specific
Not Adjustable
Not Adjustable
Adjustable
C
μF
OUT
R
10
mΩ
MΩ
pF
ESR
50
40
0
R
0.4
60
O
–45
C
C
30
–90
C
3.3
100
402
133
5
pF
PL
20
–135
–180
–225
–270
–315
–360
–405
–450
R
kΩ
kΩ
kΩ
V
Not Adjustable
Adjustable
C
10
R1
R2
0
Adjustable
–10
–20
–30
–40
–50
V
Application Specific
Application Specific
Not Adjustable
Not Adjustable
Application Specific
Not Adjustable
OUT
V
3.3
35
V
IN
GAIN
g
g
μmho
mho
μH
ma
PHASE
7.5
2.7
1.3*
mp
100
1k
10k
100k
1M
L
FREQUENCY (Hz)
3467 F07
f
MHz
S
*2.1MHz for LT3467A
Figure 7.Bode Plot of 3.3V to 5V Application
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.
U
TYPICAL APPLICATIO S
Li-Ion to 6V
Lithium-Ion to 6V Step-Up DC/DC Converter
95
90
85
80
75
70
65
60
55
50
V
= 4.2V
L1
IN
D1
2.2μH
V
IN
V
V
= 3.8V
OUT
6V
IN
2.7V
V
= 2.7V
TO 4.2V
IN
R1
275mA AT V = 2.7V
IN
501k
V
SW
490mA AT V = 3.8V
IN
C1
2.2μF
IN
C3
1.8pF
590mA AT V = 4.2V
IN
SHDN
C4
SHDN
LT3467
SS
FB
C2
15μF
R2
133k
GND
0.047μF
C1, C2: X5R OR X7R, 6.3V
3467 TA02
D1: ON SEMICONDUCTOR MBRM120
L1: SUMIDA CR43-2R2
50 100
300 400 500 600 700
(mA)
200
I
OUT
3467 TA02b
3467afc
11
LT3467/LT3467A
U
TYPICAL APPLICATIO S
4-Cell to 5V SEPIC Converter
C3
1μF
L1
10μH
D1
V
4V TO 6.5V
OUT
5V
325mA AT V = 4V
C1
IN
400mA AT V = 5V
IN
2.2μF
V
SW
IN
450mA AT V = 6.5V
IN
255k
SHDN
SHDN
C5
4.7pF
4-CELL
BATTERY
LT3467
L2
10μH
C2
10μF
SS
FB
C4
0.047μF
GND
84.5k
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
D1
V
OUT
V
IN
40V
5V
20mA
C1
4.7μF
V
SW
IN
SHDN
LT3467
R1
412k
SHDN
C2
1μF
FB
SS
C3
0.1μF
R2
13.3k
GND
C1: X5R or X7R, 6.3V
C2: X5R or X7R, 50V
3467 TA04a
D1: ON SEMICONDUCTOR, MBRM140
L1: SUMIDA CD43-2R7
15V Dual Output Converter with Output Disconnect
C4
1μF
L1
10μH
D1
V
IN
5V
15V
100mA
C1
R3
R1
2.2μF
C5
1μF
V
SW
1Ω
147k
IN
OFF ON
SHDN
D2
C2
2.2μF
LT3467
GND
SS
FB
C6
0.047μF
R2
13.3k
D3
C3
2.2μF
C1: X5R or X7R, 6.3V
C2 TO C5: X5R or X7R, 16V
D1 TO D4: PHILIPS PMEG 2005
L1: SUMIDA CR43-100
R4
D4
1Ω
–15V
100mA
3467 TA05
3467afc
12
LT3467/LT3467A
U
TYPICAL APPLICATIO S
9V, 18V, –9V Triple Output TFT-LCD Bias Supply with Soft-Start
D1
D2
C3
18V
10mA
C4
0.1μF
1μF
L1
4.7μH
Start-Up Waveforms
D5
V
9V
220mA
IN
3.3V
C1
2.2μF
9V OUTPUT
5V/DIV
R1
124k
V
SW
IN
V
SHDN
SHDN
LT3467
–9V OUTPUT
5V/DIV
C5
10μF
SS
FB
3.3V
GND
C7
0.1μF
R2
20k
0V
18V OUTPUT
10V/DIV
C2
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
I
L1 0.5A/DIV
D4
D3
C6
1μF
2ms/DIV
–9V
10mA
3467 TA07a
8V, 23V, –8V Triple Output TFT-LCD Bias Supply with Soft-Start
D1
C3
D2
D3
D4
23V
10mA
C4
C5
0.1μF
C6
1μF
0.1μF
0.1μF
Start-Up Waveforms
L1
4.7μH
D7
V
IN
8V
270mA
8V OUTPUT
5V/DIV
3.3V
SHDN
3.3V
C1
R1
V
SW
2.2μF
IN
–8V OUTPUT
5V/DIV
113k
V
SHDN
C7
10μF
LT3467
SS
FB
23V OUTPUT
10V/DIV
GND
R2
21k
0V
C9
C2
0.1μF
0.1μF
IL1 0.5A/DIV
C1: X5R OR X7R, 6.3V
D5
D6
C2 TO C4, C7, C8: X5R OR X7R, 10V
C5: X5R OR X7R, 16V
2ms/DIV
C8
C6: X5R OR X7R, 25V
1μF
D1 TO D6: PHILIPS BAT54S OR EQUIVALENT
D7: PHILIPS PMEG 2005
–8V
3467 TA08a
10mA
L1: PANASONIC ELT5KT4R7M
3467afc
13
LT3467/LT3467A
TYPICAL APPLICATIO S
U
Single Li-Ion Cell to 5V Boost Converter
Efficiency
95
90
85
80
75
70
65
60
55
50
L1
D1
0.9μH
V
IN
V
OUT
5V
2.6V
TO 4.2V
R1
8.06k
600mA AT V = 4.2V
IN
V
= 4.2V
IN
V
SW
360mA AT V = 3.3V
IN
C1
IN
V
= 3.3V
C4*
75pF
IN
250mA AT V = 2.6V
IN
4.7μF
SHDN
OFF ON
C3
V
= 2.6V
IN
LT3467A
SS
FB
C2*
22μF
R2
2.67k
GND
0.047μF
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 TA10a
50 100 150 200 250 300 350 400 450 500
(mA)
I
OUT
3467 TA09b
2.6V – 3.3V to 5V Boost Converter
Efficiency
90
85
80
75
70
65
60
55
50
L1
D1
1.5μH
V
IN
V
OUT
5V
2.6V
TO 3.3V
V
= 3.3V
R1
430mA AT V = 3.3V
270mA AT V = 2.6V
IN
IN
IN
V
= 2.6V
IN
8.06k
V
SW
C1
IN
C4
56pF
4.7μF
SHDN
LT3467A
OFF ON
C3
SS
FB
C2
10μF
R2
2.67k
GND
0.047μF
C1, C2: X5R OR X7R, 6.3V
D1: PHILIPS PMEG 2010
L1: FDK MIP3226D1R5M
3467 TA09a
50 100 150 200 250 300 350 400 450 500
(mA)
I
OUT
3467 TA08b
3.3V to 15V, 135mA Step-Up Converter
Efficiency
90
80
70
60
50
40
30
L1
D1
6.8μH
V
IN
V
OUT
3.3V
15V
R1
135mA
16.5k
V
SW
C1
4.7μF
IN
C4
68pF
SHDN
LT3467A
OFF ON
C3
SS
FB
C2
2.2μF
R2
1.5k
GND
0.047μF
C1: X5R OR X7R, 6.3V
C2: X5R OR X7R, 16V
D1: PHILIPS PMEG 2010
3467 TA11a
140
20
40
60
80 100 120
160
L1: SUMIDA CMD4D13-6R8MC
I
(mA)
OUT
3467 TA10b
3467afc
14
LT3467/LT3467A
U
PACKAGE DESCRIPTIO
DDB Package
8-Lead Plastic DFN (3mm × 2mm)
(Reference LTC DWG # 05-08-1702 Rev B)
0.61 0.05
(2 SIDES)
R = 0.115
0.40 0.10
3.00 0.10
(2 SIDES)
TYP
R = 0.05
TYP
5
8
0.70 0.05
2.55 0.05
1.15 0.05
2.00 0.10
PIN 1 BAR
(2 SIDES)
TOP MARK
PIN 1
R = 0.20 OR
0.25 × 45°
(SEE NOTE 6)
PACKAGE
OUTLINE
0.56 0.05
(2 SIDES)
CHAMFER
4
1
(DDB8) DFN 0905 REV B
0.25 0.05
0.25 0.05
0.75 0.05
0.200 REF
0.50 BSC
2.20 0.05
(2 SIDES)
0.50 BSC
2.15 0.05
(2 SIDES)
0 – 0.05
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
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
S6 Package
6-Lead Plastic TSOT-23
(Reference LTC DWG # 05-08-1636)
2.90 BSC
(NOTE 4)
0.62
MAX
0.95
REF
1.22 REF
1.4 MIN
1.50 – 1.75
2.80 BSC
3.85 MAX 2.62 REF
(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
DATUM ‘A’
0.01 – 0.10
1.00 MAX
0.30 – 0.50 REF
1.90 BSC
0.09 – 0.20
(NOTE 3)
S6 TSOT-23 1005
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
3467afc
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 represen-
tation that the interconnection ofits circuits as described herein willnotinfringe on existing patentrights.
15
LT3467/LT3467A
L1
4.7μH
D1
V
OUT
V
IN
5V
12V
C1
270mA
R1
2.2μF
115k
V
SW
IN
C4*
22pF
C2
10μF
LT3467
GND
SS
FB
C3
0.047μF
R2
13.3k
3467 TA06a
Figure 8. 5V to 12V, 270mA Step-Up Converter
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LT1615/LT1615-1
300mA/80mA (I ), High Efficiency Step-Up DC/DC Converter V : 1V to 15V, V
= 34V, I = 20μA,
SW
IN
OUT(MAX) Q
<1μA, ThinSOT Package
I
SD
LT1618
1.5A (I ), 1.25MHz, High Efficiency
90% Efficiency, V : 1.6V to 18V, V
= 35V,
OUT(MAX)
SW
IN
Step-Up DC/DC Converter
I = 1.8mA, I <1μA, MS Package
Q
SD
LTC1700
No R
TM, 530kHz, Synchronous Step-Up DC/DC Controller 95% Efficiency, V : 0.9V to 5V, I = 200μA, I <10μA,
SENSE IN Q SD
MS Package
LTC1871
Wide Input Range, 1MHz, No R
Flyback and SEPIC Controller
Current Mode Boost,
92% Efficiency, V : 2.5V to 36V, I = 250μA, I <10μA,
SENSE
IN
Q
SD
MS Package
LT1930/LT1930A
LT1946/LT1946A
LT1961
1A (I ), 1.2MHz/2.2MHz, High Efficiency
High Efficiency, V : 2.6V to 16V, V
Q SD
= 34V,
SW
IN
OUT(MAX
Step-Up DC/DC Converter
I = 4.2mA/5.5mA, I <1μA, ThinSOT Package
1.5A (I ), 1.2MHz/2.7MHz, High Efficiency
High Efficiency, V : 2.45V to 16V, V
= 34V,
SW
IN
OUT(MAX)
Step-Up DC/DC Converter with Soft-Start
I = 3.2mA, I <1μA, MS8 Package
Q
SD
1.5A (I ), 1.25MHz, High Efficiency
90% Efficiency, V : 3V to 25V, V
Q SD
= 35V,
SW
IN
OUT(MAX)
Step-Up DC/DC Converter
I = 0.9mA, I <6μA, MS8E Package
LTC3400/LTC3400B
LTC3401
600mA (I ), 1.2MHz, Synchronous Step-Up DC/DC Converter 92% Efficiency, V : 0.85V to 5V, V
= 5V,
OUT(MAX)
SW
IN
I = 19μA/300μA, I <1μA, ThinSOT Package
Q
SD
1A (I ), 3MHz, Synchronous Step-Up DC/DC Converter
97% Efficiency, V : 0.5V to 5V, V
= 5.5V,
SW
IN
OUT(MAX)
OUT(MAX)
I = 38μA, I <1μA, MS Package
Q
SD
LTC3402
2A (I ), 3MHz, Synchronous Step-Up DC/DC Converter
97% Efficiency, V : 0.5V to 5V, V
= 5.5V,
SW
IN
I = 38μA, I <1μA, MS Package
Q
SD
LT3464
85mA (I ), High Efficiency Step-Up DC/DC Converter
V : 2.3V to 10V, V
Q SD
= 34V,
SW
IN
OUT(MAX)
with Integrated Schottky and PNP Disconnect
I = 25μA, I <1μA, ThinSOT Package
No R
is a trademark of Linear Technology Corporation.
SENSE
3467afc
LT 0707 REV C • PRINTED IN USA
LinearTechnology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
16
●
●
(408) 432-1900 FAX: (408) 434-0507 www.linear.com
© LINEAR TECHNOLOGY CORPORATION 2003
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