LTG2 [Linear]
Micropower Boost Converter with Schottky and Output Disconnect in ThinSOT™; 微功率升压转换器与肖特基和输出断接采用ThinSOT ™
| 型号： | LTG2 |
| 厂家： | 
Linear |
| 描述： | Micropower Boost Converter with Schottky and Output Disconnect in ThinSOT™ |
| 文件： | 总16页 (文件大小：236K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
LT3464
Micropower Boost
Converter with Schottky and
Output Disconnect in ThinSOT™
U
DESCRIPTIO
FEATURES
The LT®3464 is a micropower step-up DC/DC converter
with integrated Schottky diode and output disconnect
packaged in an 8-lead low profile (1mm) SOT-23. The
small package size, high level of integration, and the use
of tiny SMT components yield a solution size of less than
40mm2. The LT3464 has a typical current limit of 115mA
as well as fast switching speed to allow the use of a chip
inductor and small ceramic capacitors. The internal PNP
disconnects the output load from the input during shut-
down, and also provides output short-circuit protection.
An auxiliary reference input allows the user to override the
internal 1.25V feedback reference with any lower value,
allowing full control of the output voltage during opera-
tion. This device features a low 25µA quiescent current,
which is further reduced to less than 0.5µA in shutdown.
A current limited fixed off-time control scheme conserves
operating current, resulting in high efficiency over a broad
range of operating current. The rugged 36V switch and
output disconnect circuitry allow outputs up to 34V to be
easily generated in a simple boost topology.
■
Tiny Solution Size
■
Low Quiescent Current
• 25µA in Active Mode
• 0.5µA in Shutdown Mode
■
Internal 115mA, 36V Switch
■
Integrated Schottky Diode
■
Integrated PNP Output Disconnect with
Short-Circuit Protection
■
Internal Reference Override Pin
■
16V at 8mA from 3.6V Input
■
12V at 20mA from 5V Input
■
Input Range: 2.3V to 10V
■
High Output Voltage: Up to 34V
■
Low Profile (1mm) SOT-23 Package
U
APPLICATIO S
■
OEL Panel Bias
■
LCD Bias
■
Handheld Computers
■
Battery Backup
, LTC and LT are registered trademarks of Linear Technology Corporation.
ThinSOT is a trademark of Linear Technolgy Corporation
■
Digital Cameras
■
Cellular Phones
U
TYPICAL APPLICATIO
Efficiency
22µH
90
V
IN
2.3V TO 10V
V
IN
= 8.4V
80
70
60
50
40
30
V
SW
IN
V
= 4.2V
IN
V
OUT
OUT
16V
0.22µF
0.33µF
CTRL
1µF
LT3464 CAP
3.48M
294k
SHDN
FB
GND
3464 TA01a
0.01
0.1
1
10
100
LOAD CURRENT (mA)
3634 TA01b
3464f
1
LT3464
W W U W
U
W
U
ABSOLUTE AXI U RATI GS
PACKAGE/ORDER I FOR ATIO
(Note 1)
ORDER PART
VIN, SHDN, CTRL Voltage ........................................ 10V
OUT, CAP Voltage .................................................... 36V
SW Voltage .............................................................. 36V
FB Voltage ................................................................. 6V
Maximum Junction Temperature .......................... 125°C
Operating Temperature Range (Note 2) .. –40°C to 85°C
Storage Temperature Range ..................–65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
TOP VIEW
NUMBER
CTRL 1
FB 2
OUT 3
GND 4
8 SHDN
7 V
6 SW
LT3464ETS8
IN
5 CAP
TS8 PART MARKING
LTG2
TS8 PACKAGE
8-LEAD PLASTIC SOT-23
TJMAX = 125°C, θJA = 140°C/W, θJC = 85°C/W
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VIN = 3.6V, unless otherwise noted. (Note 2)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Minimum Input Voltage
Quiescent Current
2.0
2.3
V
Not Switching
25
0.01
36
0.5
µA
µA
V
= 0.2V
SHDN
FB Comparator Trip Voltage
FB Comparator Hysteresis
FB Pin Bias Current
V
Falling, V
= 3.6V
●
●
1.215
1.250
10
1.275
V
mV
nA
FB
CTRL
V
= 1.25V, V
= 3.6V
3
30
FB
CTRL
FB Voltage Line Regulation
Switch Off Time
2.3V < V < 10V
0.05
0.1
%/V
IN
V
V
-V = 5V
250
1.0
ns
µs
CAP IN
-V = 0V
CAP IN
Switch Leakage Current
V
= 36V
0.02
190
115
600
1
1
µA
mV
mA
mV
µA
SW
Switch V
I
= 80mA
SW
300
140
750
10
CESAT
Switch Current Limit
85
Schottky Forward Voltage
Schottky Reverse Leakage
I
= 110mA
= 36V
SCHOTTKY
V
CAP-SW
PNP Disconnect V
I
I
= 200µA
= 10mA
100
190
mV
mV
CAP-OUT
OUT
OUT
PNP Disconnect Q Current
PNP Disconnect Leakage
PNP Disconnect Current Limit
SHDN Pin Current
I
= 0, V
= 36V (Note 3)
CAP
1.5
0.1
45
5
5
5
µA
µA
mA
µA
V
OUT
SHDN = 0.2, V
= 10V, V
= 0V
= 0V
OUT
CAP
OUT
V
V
= 10V, V
25
75
10
CAP
= 3.6V
SHDN
SHDN Input Voltage High
SHDN Input Voltage Low
CTRL Pin Bias Current
CTRL to FB Offset
2.3
0.2
80
7
V
V
V
= 0.5V, V = 1V
●
6
2
nA
mV
CTRL
CTRL
FB
= 0.5V (Note 4)
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 3: Current consumed by Disconnect PNP when there is no load on
the OUT pin.
Note 2: The LT3464E is guaranteed to meet performance specifications
from 0°C to 70°C. Specifications over the –40°C to 85°C operating
temperature range are assured by design, characterization and correlation
with statistical process controls.
Note 4: This figure is computed according to ((V falling + V rising)/2)
FB FB
–V
CONTROL
.
3464f
2
LT3464
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Switch Saturation Voltage
ISW = 80mA
Switch Off-Time, VCAP – VIN = 5V
Switch Current Limit
220
200
180
160
140
120
100
140
120
100
80
400
350
300
250
200
150
100
50
60
40
20
0
–50
0
–50
0
25
50
75
100
–50
0
25
50
75
100
100
30
–25
–25
0
25
50
75
100
–25
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
3464 G01
3464 G02
3464 G03
Output Disconnect Voltage Drop
Minimum Switch On-Time
Switch Off-Time, VCAP – VIN = 0V
100
90
80
70
60
50
40
30
20
10
0
300
250
200
150
100
50
1.3
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
I
= 10mA
OUT
I
= 200µA
OUT
0
–50
0
25
50
75
–25
–50
0
25
50
75
100
–50
0
25
50
75
100
–25
–25
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
3464 G05
3464 G06
3464 G04
Output Disconnect Quiescent
Current
Output Disconnect Voltage Drop
Output Disconnect Current Limit
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
60
50
40
30
20
10
0
300
250
200
150
100
50
0
–50
0
25
50
75
100
–50
0
25
50
75
100
0
10
20
–25
–25
TEMPERATURE (°C)
TEMPERATURE (°C)
COLLECTOR CURRENT (mA)
3464 G07
3464 G08
3464 G09
3464f
3
LT3464
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Schottky Forward Drop
at ID = 110mA
Schottky Reverse Leakage
Schottky Forward Voltage
20
16
12
8
250
200
150
100
50
800
750
700
650
600
550
500
450
400
350
300
V
– SW = 36V
CAP
4
0
0
–50
0
25
50
75
75
75
100
200
400
500
600
700
800
–25
300
–50
0
25
50
75
100
–25
TEMPERATURE (°C)
FORWARD VOLTAGE (mV)
TEMPERATURE (°C)
3464 G11
3464 G20
3464 G10
Shutdown Pin Current
VSHDN = 3.6V
Quiescent Current in
Shutdown Mode
Quiescent Current
30
28
26
24
22
20
18
16
14
12
10
12
10
8
16
14
12
10
8
6
6
4
4
2
2
0
0
–50
0
25
50
75
100
–50 –25
0
25
50
100
–25
–50
0
25
50
75
100
–25
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
3464 G14
3464 G13
3464 G12
Quiescent Current in
Regulation with No Load
FB Pin Voltage
SHDN Pin Threshold Voltage
1.30
1.28
1.26
1.24
1.22
1.20
70
60
50
40
30
20
10
0
3.0
2.8
2.6
2.4
2.2
2.0
1.8
1.6
1.4
1.2
1.0
V
= 5V
IN
FRONT PAGE SCHEMATIC
–50
0
25
50
100
–25
6
8
10
12
14
16
18
20
–50
0
25
50
75
100
–25
TEMPERATURE (°C)
TEMPERATURE (°C)
V
OUT
(V)
3464 G16
3464 G18
3464 G15
3464f
4
LT3464
U W
TYPICAL PERFOR A CE CHARACTERISTICS
FB Pin Voltage vs
CTRL Pin Voltage
FB and CTRL Pin
Bias Currents
FB Pin Hysteresis
1.50
1.25
1.00
0.75
0.50
0.25
0
12
10
8
8
7
6
5
4
3
2
1
0
CTRL PIN
6
FEEDBACK PIN
4
2
0
0
0.5 0.75 1.0 1.25 1.5 1.75
0.25
–50
0
25
50
75
100
–50
0
25
50
75
100
–25
–25
CONTROL PIN VOLTAGE (V)
TEMPERATURE (°C)
TEMPERATURE (°C)
3464 G17
3464 G18
3464 G19
U
U
U
PI FU CTIO S
CTRL(Pin 1): Internal ReferenceOverride Pin. This allows GND (Pin 4): Ground. Tie this pin directly to the ground
the FB voltage to be externally set between 0V and 1.25V. plane.
Tie this pin to above 1.5V (VIN for example) to use the
CAP (Pin 5): PNP Emitter and Schottky Cathode. This pin
internal 1.25V reference.
connects to the output capacitor, and optionally to the
external phase-lead capacitor.
R2
R1
VOUT = VCTRL
+1
SW (Pin 6): Switch Pin and Schottky Anode. This is the
collector of the internal NPN power switch. Minimize the
metal trace area connected to the pin to minimize EMI.
when VCTRL is less than 1.25V (see Figure 4)
VIN (Pin 7): Input Supply Pin: Bypass this pin with a
FB (Pin 2): Feedback Pin. The LT3464 regulates its feed-
back pin to 1.25V if the internal reference is used or to
VCTRL if the CTRL pin is between 0V and 1.25V. Connect
the feedback resistor divider tap to this pin. Set the output
voltage by selecting R1 and R2 (see Figure 4).
capacitor located as close to the device as possible.
SHDN (Pin 8): Shutdown Pin. This pin is used to put the
deviceinshutdownmode. Tiethepinlowtoshutdownthe
LT3464. Tie high for normal operation See the electrical
specifications for the required voltages.
VOUT
R2 = R1
– 1
VREF
OUT (Pin 3): PNP Collector. This is the output of the
Output Disconnect circuit. Bypass this pin with at least a
0.1µF capacitor connected to the CAP pin or to ground.
3464f
5
LT3464
W
BLOCK DIAGRA
V
IN
SW
6
CAP
5
OUT
3
7
DELAY
C
PL
S
R
Q
Q
FB
2
1
+
–
–
CTRL
OUT
ANTI
SAT
+
–
1.25V
OUT
12mV
0.1Ω
8
SHDN
V
REF
4
3464 BD
GND
U
OPERATIO
The LT3464 uses a constant off-time control scheme in
conjunction with Burst Mode® operation to provide high
efficiency over a wide range of output current. Operation
can best be understood by studying the Block Diagram.
When the FB pin voltage is lower than the 1.25V reference,
the hysteretic comparator enables the power section,
causing the chip to start switching, thus charging the
output capacitor. When the output voltage increases
enough to overcome the hysteresis, the feedback com-
paratorshutsoffthepowersectionleavingonlylowpower
circuitry running until the output voltage falls again. This
cycle repeats, keeping the output voltage within a small
window. The switching action is as follows: The switch
turns on, and current through it starts to ramp up until the
point where the current limit is reached, at which point the
switch turns off for a fixed amount of time. While the
switch is off the inductor is delivering current to the load.
When the off time expires, the switch turns on again until
the current limit is reached, and the cycle repeats.
This chip includes an internal power Schottky diode and a
PNP transistor for output disconnect. The PNP transistor
disconnects the load from the input during shutdown. The
PNP control circuitry is designed to keep the PNP out of
saturation across a wide range of current, to keep quies-
cent current to a minimum and to provide current limiting
to protect the chip during short-circuit conditions.
Burst Mode is a registered a trademark of Linear Technolgy Corporation.
3464f
6
LT3464
U W
W
SWITCHI G TI E WAVEFOR S
Operating Waveforms
Start up Waveforms
IL
IL
0.1A/DIV
0.1A/DIV
VOUT
50mV/DIV
VOUT
10V/DIV
50µs/DIV
5µs/DIV
VIN = 5V
VOUT = 20V
ILOAD = 1mA
L = 22µH
Shutdown Waveforms
SHDN
5V/DIV
VIN = 5V
GND
CAP PIN VOLTAGE
V
OUT: THE OUTPUT DISCONNECT
ALLOWS VOUT TO BE AT
GROUND DURING SHUTDOWN
1ms/DIV
3464f
7
LT3464
U
W U U
APPLICATIO S I FOR ATIO
Choosing an Inductor
in discontinuous mode. If the left hand side of inequality 1
evaluatestolessthantOFF, thenuseEquation3tocalculate
maximum output current. Otherwise, use Equation 2.
The low current limit and fast switching of the LT3464
allow the use of very small surface mount inductors. The
minimum inductor size that may be used in a given
application depends on required efficiency and output
current. Some inductors that work with the LT3464 are
listed in Table 1, although there are many other manufac-
turers and devices that can be used. Consult each manu-
facturer for more detailed information and for their entire
selection of related parts. Many different sizes and shapes
are available.
This inequality is true when the LT3464 is operating in
discontinuous mode.
LILIM
< tOFF
(INEQUALITY 1)
(VOUT – V + VF)
IN
Usethisequationtocalculatethemaximumoutputcurrent
when the LT3464 is operating in continuous mode.
Table 1. Recommended Inductors
IOUT(CM)
=
PART NUMBER
µH
DCR
(Ω)
CURRENT
(mA)
MANUFACTURER
(2LILIM + tOFF(V – VOUT – VF))(V – VCESAT
)
IN
IN
(2)
LQH32CN680K53
LQH32CN470K53
LQH32CN220K53
68
47
22
2.2
1.3
0.71
130
170
250
Murata
814-237-1431
www.murata.com
2L(VOUT – VCESAT + VF)
Usethisequationtocalculatethemaximumoutputcurrent
when the LT3464 is operating in discontinuous mode.
ELJPC220KF
ELJPA470KF
22
47
4.0
2.25
160
135
Panasonic
714-373-7334
www.panasonic.com
CMD4D11-47
47
2.2
180
Sumida
847-956-0666
IOUT(DCM)
=
LILIM2(V – VCESAT
)
www.Sumida.com
(3)
IN
LB2016-220
22
22
33
22
33
22
68
100
1.0
5.5
7.1
2.7
4.8
1.2
3.3
4.3
105
125
110
160
120
105
120
100
Taiyo Yuden
2(LILIM + VIN tOFF – tOFF VCESAT)(–V + VOUT + VF)
LEM2520-220
LEM2520-330
LEMC2520-220
LEMC2520-330
LEMF2520-220
LEMC3225-680
LEMC3225-101
408-573-4150
www.t-yuden.com
IN
WhereVF istheSchottkyforwardvoltage, ILIM istheswitch
current limit, tOFF is the switch off time, and VCESAT is the
switchsaturationvoltage.SeetheElectricalSpecifications.
Figures1through3showtheworst-casemaximumoutput
current as given by Equations 2 and 3 using 20% inductor
derating and worst-case LT3464 specifications. Also note
that for some applications the maximum output current is
limited to 25mA by the output disconnect circuitry.
The following set of formulas can be used to calculate
maximum output current given VIN, VOUT and L values.
Inequality1isusedtodetermineiftheLT3464isoperating
25
25
17.5
15.0
12.5
10.0
7.5
5.0
2.5
0
L = 47µH
20
20
15
10
5
L = 47µH
L = 47µH
L = 22µH
15
L = 22µH
L = 22µH
L = 10µH
L = 10µH
L = 10µH
10
5
L = 4.7µH
L = 4.7µH
L = 4.7µH
0
0
15
20
25
30
35
10
15
20
25
30
35
10
15
20
25
30
35
V
(V)
OUT
V
(V)
3464 F03
OUT
3464 F02
V
OUT
(V)
3464 F01
Figure 3. Maximum Output Current
Figure 1. Maximum Output Current
VIN = 3.6V
Figure 2. Maximum Output Current
VIN = 5V
VIN = 8.4V
3464f
8
LT3464
W U U
APPLICATIO S I FOR ATIO
U
user to select between using the built-in reference, and
supplying an external reference voltage. The voltage at the
CTRL pin can be adjusted while the chip is operating to
alter the output voltage of the LT3464 for purposes such
as display dimming or contrast adjustment. To use the
internal1.25Vreference,theCTRLpinmustbeheldhigher
than 1.5V, which can be done by tying it to VIN. When the
CTRL pin is held between 0V and 1.2V the LT3464 will
regulate the output such that the FB pin voltage is equal to
the CTRL pin voltage.
Capacitor Selection
The small size and low ESR of ceramic capacitors makes
themsuitableforLT3464applications.X5RandX7Rtypes
are recommended because they retain their capacitance
over wider voltage and temperature ranges than other
types such as Y5V or Z5U. A 1µF input capacitor and a
0.22µF to 0.47µF output capacitor are sufficient for most
LT3464 applications. Always use a capacitor with a suffi-
cient voltage rating. Table 2 shows a list of several capaci-
tor manufacturers. Consult the manufacturers for more
detailedinformationandfortheirentireselectionofrelated
parts.
To set the output voltage, select the values of R1 and R2
according to the following equation (see Figure 4).
Table 2. Recommended Ceramic Capacitor Manufacturers
VOUT
VREF
MANUFACTURER
Taiyo Yuden
AVX
PHONE
URL
R2 = R1
– 1
408-573-4150
843-448-9411
814-237-1431
408-986-0424
www.t-yuden.com
www.avxcorp.com
www.murata.com
www.kemet.com
Where VREF =1.25V if the internal reference is used, or
VREF = VCTRL if VCTRL is between 0V and 1.2V.
Murata
Kemet
Choosing a Feedback Node
Output Voltage Ripple
The top of the feedback divider may be connected to the
OUT pin or to the CAP pin (see Figure 4). Regulating the
OUT pin eliminates the output offset resulting from the
voltage drop across the output disconnect. However, in
the case of a short-circuit fault at the OUT pin, the LT3464
will switch continuously because the FB pin is low. While
operating in this open-loop condition, the rising voltage at
theCAPpin islimitedonlybythecurrentlimitoftheoutput
disconnect. Given worst-case parameters this voltage
may reach 25V. When the short-circuit is removed, the
OUT pin will bounce up to the voltage on the CAP pin,
potentially exceeding the set output voltage until the
capacitor voltages fall back into regulation. While this is
harmless to the LT3464, this should be considered in the
context of the external circuitry if short-circuit events are
expected.
Using low ESR capacitors will help minimize the output
ripple voltage, but proper selection of the inductor and the
output capacitor also plays a big role. The LT3464 pro-
vides energy to the load in bursts by ramping up the
inductor current, then delivering that current to the load.
If too large an inductor value or too small a capacitor value
is used, the output ripple voltage will increase because the
capacitor will be slightly overcharged each burst cycle. To
reduce this effect, a larger output capacitor may be used.
TheLT3464alsoincludesanon-chipphase-leadcapacitor
between the CAP pin and the FB pin to greatly reduce
ripple; however, certain applications can benefit from
additional capacitance in parallel with the integrated ca-
pacitor, which may be added externally between the CAP
and FB pins. Typical effective values range from 4.7pF to
20pF. Since the FB pin sits at a low voltage, be sure the
chosen capacitor has a sufficient voltage rating.
Regulating the CAP pin ensures that the voltage on the
OUTpinneverexceedsthesetoutputvoltageafterashort-
circuit event. However, this setup does not compensate
for the voltage drop across the output disconnect, result-
ing in an output voltage that is slightly lower than the
voltage set by the resistor divider. The next section dis-
cusses how to compensate for this drop.
Setting Output Voltage and the
Auxiliary Reference Input
The LT3464 is equipped with both an internal 1.25V
reference and an auxiliary reference input. This allows the
3464f
9
LT3464
W U U
U
APPLICATIO S I FOR ATIO
300
250
200
150
100
50
6
6
7
7
V
V
IN
SW
OUT
SW
OUT
IN
3
5
3
5
V
OUT
V
OUT
1
8
1
8
CTRL
LT3464 CAP
SHDN
CTRL
LT3464 CAP
SHDN
R2
R1
R2
2
2
FB
FB
GND
4
GND
4
R1
0
0
5
10
15
20
25
30
3464 F01
COLLECTOR CURRENT (mA)
3464 F02
Figure 4. Feedback Connection Using the CAP Pin and the OUT Pin
Figure 5: Output Disconnect Voltage Drop (VDROP) vs Current
indefinite short, but care must be taken to avoid exceeding
the maximum junction temperature.
Output Disconnect Considerations
The LT3464 is equipped with an output disconnect that
isolates the load from the input during shutdown. See the
Operation section for a functional diagram. The output
disconnect uses a pass PNP coupled with circuitry that
varies the base current such that the transistor is consis-
tently at the edge of saturation, thus yielding the best
compromise between VCE(SAT) and low quiescent current.
To remain stable, this circuit requires a bypass capacitor
connected between the OUT pin and the CAP pin or
betweentheOUTpinandground.Aceramiccapacitorwith
a value of at least 0.1µF is a good choice.
Inrush Current
When VIN is stepped from ground to operating voltage
whiletheoutputcapacitorisdischarged, aninrushcurrent
will flow through the inductor and integrated Schottky
diode into the output capacitor. Conditions that increase
inrush current include a larger more abrupt voltage step at
VIN, a larger output capacitor tied to the CAP pin, and an
inductor with a low saturation current.
Whiletheinternaldiodeisdesignedtohandlesuchevents,
the inrush current should not be allowed to exceed 1 amp.
For circuits that use output capacitor values within the
recommended range and have input voltages of less than
5V, inrush current remains low, posing no hazard to
the device. In cases where there are large steps at VIN
(more than 5V) and/or a large capacitor is used at the CAP
pin, inrush current should be measured to ensure safe
operation.
The PNP VCE(SAT) varies with load current as shown in
Figure 5. This voltage drop (VDROP) can be accounted for
when using the CAP pin as the feedback node by setting
the output voltage according to the following formula:
VOUT + VDROP
R2 = R1
– 1
VREF
In addition, the disconnect circuit has a built in current
limit of 25mA (minimum) to protect the chip during short-
circuit. This feature allows the LT3464 to tolerate an
3464f
10
LT3464
W U U
APPLICATIO S I FOR ATIO
U
Board Layout Considerations
pin has sharp rising and falling edges. Minimize the length
and area of all traces connected to the SW pin and always
use a ground plane under the switching regulator to
minimize interplane coupling. In addition, the ground
connection for the feedback resistor R1 should be tied
directly to the GND pin and not shared with any other
component, ensuringaclean, noise-freeconnection. Rec-
ommended component placement is shown in Figure 6.
As with all switching regulators, careful attention must be
paid to the PCB board layout and component placement.
Tomaximizeefficiency, switchriseandfalltimesaremade
as short as possible. To prevent electromagnetic interfer-
ence (EMI) problems, proper layout of the high frequency
switching path is essential. The voltage signal of the SW
GND
GND
V
IN
V
OUT
VIAS TO GROUND PLANE
VIA TO CONTROL
VIA TO SHDN
3464 F07
Figure 6. Recommended Layout
3464f
11
LT3464
U
TYPICAL APPLICATIO S
15V Output Converter with Output Disconnect
L1
22µH
V
IN
2.3V TO 10V
6
7
V
SW
IN
3
5
V
OUT
15V
OUT
1
8
C3
CTRL
C1
1µF
0.22µF
V
(V)
I
(mA)
OUT
LT3464 CAP
IN
C2
0.22µF
R2
3.32M
SHDN
3.6
5.0
8.4
7.0
2
FB
10.0
19.0
R1
301k
GND
4
3464 TA02
C1: TAIYO YUDEN LMK107 BJ105MA-T
C2: TAIYO YUDEN EMK107 BJ224MA-T
C3: TAIYO YUDEN EMK107 BJ224MA-T
L1: MURATA LQH32CN220K
34V Output Converter with Output Disconnect
L1
47µH
V
IN
2.3V TO 10V
6
7
V
SW
IN
3
5
V
OUT
34V
OUT
1
8
C3
CTRL
C1
1µF
0.22µF
LT3464 CAP
V
(V)
I
(mA)
OUT
IN
C2
0.33µF
R2
2.61M
SHDN
3.6
3.5
4.5
7.5
2
FB
5.0
8.4
R1
100k
GND
4
3464 TA03
C1: TAIYO YUDEN LMK107 BJ105MA-T
C2: TAIYO YUDEN GMK212 BJ334MG-T
C3: TAIYO YUDEN UMK212 BJ224MG-T
L1: MURATA LQH32CN470K
20V Output Converter with Output Disconnect Using an 0805
Inductor and 0603 Capacitors
L1
10µH
V
IN
2.3V TO 10V
6
7
V
SW
IN
3
5
V
OUT
20V
OUT
1
8
C3
CTRL
C1
0.1µF
1µF
LT3464 CAP
V
(V)
I
(mA)
OUT
IN
C2
0.1µF
R2
4.53M
SHDN
3.6
5.0
8.4
3.0
4.0
6.0
2
FB
R1
301k
GND
4
3464 TA04
C1: TAIYO YUDEN LMK107 BJ105MA-T
C2: TAIYO YUDEN TMK107 BJ104MA-T
C3: TAIYO YUDEN TMK107 BJ104MA-T
L1: TAIYO YUDEN LB 2012T100MR
3464f
12
LT3464
U
TYPICAL APPLICATIO S
20V Output Converter with Output Disconnect
L1
47µH
V
IN
2.3V TO 10V
6
7
V
SW
3
IN
V
OUT
OUT
20V
1
8
C3
CTRL
C1
1µF
0.22µF
V
(V)
I
(mA)
OUT
IN
5
2
LT3464 CAP
3.6
5.0
8.4
6.0
C2
0.33µF
R2
4.53M
SHDN
9.0
FB
16.5
R1
301k
GND
4
3464 TA05
C1: TAIYO YUDEN LMK107 BJ105MA-T
C2: TAIYO YUDEN GMK212 BJ334MG-T
C3: TAIYO YUDEN UMK212 BJ224MG
L1: MURATA LQH32CN470K
20V Output Converter with Soft Start
L1
22µH
V
IN
2.3V TO 10V
6
7
OFF ON
V
SW
3
IN
V
OUT
OUT
20V
8
1
C3
SHDN
CTRL
C4
1µF
0.22µF
V
(V)
I
(mA)
OUT
IN
5
2
R1
LT3464 CAP
300k
3.6
5.0
8.4
5.0
6.5
C2
0.33µF
R2
4.53M
FB
C4
11.0
R1
301k
GND
4
0.1µF
3464 TA06
C1: TAIYO YUDEN LMK107 BJ105MA-T
C2: TAIYO YUDEN GMK212 BJ334MG-T
C3: TAIYO YUDEN EMK107 BJ224MA-T
L1: MURATA LQH32CN220K
3464f
13
LT3464
U
TYPICAL APPLICATIO S
8V Output Converter with Output Disconnect
L1
22µH
V
IN
2.3V TO 7V
6
7
V
SW
3
IN
V
OUT
8V
OUT
8
1
C3
SHDN
CTRL
C4
0.47µF
5
2
1µF
V
(V)
I
(mA)
OUT
LT3464 CAP
IN
R2
1.62M
C2
2.2µF
C4
20pF
3.6
5.0
13.5
20
FB
R1
301k
GND
4
3464 TA07
C1: TAIYO YUDEN CE LMK107 BJ105MA-T
C2: TAIYO YUDEN CE LMK212 BJ225MG-T
C3: TAIYO YUDEN CE LMK107 BJ474MA-T
L1: MURATA LQH32CN220K
±20V Dual Output Converter with Output Disconnect
–V
OUT
IOUT = 2.5mA AT VIN = 3.6V
–20V
C4
L1
47µH
C5
0.33µF
D1
D2
0.33µF
V
IN
2.3V TO 10V
6
7
V
SW
OUT
IN
3
5
V
OUT
I
OUT = 2.5mA AT VIN = 3.6V
20V
1
8
C3
CTRL
C1
1µF
0.22µF
LT3464 CAP
C2
0.33µF
R2
4.53M
SHDN
2
FB
R1
301k
GND
4
3464 TA08
C1: TAIYO YUDEN LMK107 BJ105MA-T
C2, C4, C5: TAIYO YUDEN GMK212 BJ334MG-T
C3: TAIYO YUDEN UMK212 BJ224MG-T
L1: MURATA LQH32CN470K
D1, D2: CENTRAL CMDSH-3
3464f
14
LT3464
U
PACKAGE DESCRIPTIO
TS8 Package
8-Lead Plastic TSOT-23
(Reference LTC DWG # 05-08-1637)
2.90 BSC
(NOTE 4)
0.52
MAX
0.65
REF
1.22 REF
1.50 – 1.75
(NOTE 4)
2.80 BSC
1.4 MIN
3.85 MAX 2.62 REF
PIN ONE ID
RECOMMENDED SOLDER PAD LAYOUT
PER IPC CALCULATOR
0.22 – 0.36
8 PLCS (NOTE 3)
0.65 BSC
0.80 – 0.90
0.20 BSC
DATUM ‘A’
0.01 – 0.10
1.00 MAX
0.30 – 0.50 REF
1.95 BSC
0.09 – 0.20
(NOTE 3)
TS8 TSOT-23 0802
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
3464f
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-
tationthattheinterconnectionofitscircuitsasdescribedhereinwillnotinfringeonexistingpatentrights.
15
LT3464
U
TYPICAL APPLICATIO S
20V Output Converter with Variable Output Voltage
and Shutdown
L1
22µH
V
IN
2.3V TO 10V
C1
1µF
6
7
V
SW
IN
3
5
V
OUT
20V
OUT
1
8
C3
DAC
CTRL
V
(V)
I
(mA)
OUT
0.22µF
IN
LT3464 CAP
3.6
5.0
8.4
5.0
C2
0.33µF
R2
4.53M
SHDN
µC
2
6.5
FB
R1
301k
GND
4
11.0
3464 TA09
C1: TAIYO YUDEN LMK107 BJ105MA-T
C2: TAIYO YUDEN GMK212 BJ334MG-T
C3: TAIYO YUDEN GMK212 BJ224MG-T
L1: MURATA LQH32CN220K
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
= 0.9V to 10V, V
LT1613
550mA (I ), 1.4MHz, High Efficiency
V
= 34V, I = 3mA, I = <1µA,
Q SD
SW
IN
OUT(MAX)
OUT(MAX)
OUT(MAX)
Step-Up DC/DC Converter
ThinSOT Package
LT1615/
LT1615-1
300mA/80mA (I ), Constant Off-Time,
V
= 1.2V to 15V, V
= 34V, I = 20µA, I = <1µA,
Q SD
SW
IN
High Efficiency Step-Up DC/DC Converter
ThinSOT Package
LT1618
LT1932
LT1937
LT1944
LT1944-1
LT1945
Constant Current, Constant Voltage, 1.4MHz,
High Efficiency Boost Regulator
V
= 1.6V to 18V, V
= 34V, I = 1.8mA, I = <1µA,
Q SD
MS Package, Up to 6 White LEDs
IN
Constant Current, 1.2MHz, High Efficiency
White LED Boost Regulator
V
IN
= 1V to 10V, V = 34V, I = 1.2mA, I = <1µA,
OUT(MAX)
Q
SD
ThinSOT Package, Up to 8 White LEDs
Constant Current, 1.2MHz, High Efficiency
White LED Boost Regulator
V
IN
= 2.5V to 10V, V = 34V, I = 1.9mA, I = <1µA,
OUT(MAX)
Q
SD
SC-70, ThinSOT Packages, Up to 4 White LEDs
Dual Output 350mA (I ), Constant Off-Time,
V
= 1.2V to 15V, V
= 34V, I = 20µA, I = <1µA,
Q SD
SW
IN
OUT(MAX)
OUT(MAX)
OUT(MAX)
High Efficiency Step-Up DC/DC Converter
MS Package
Dual Output 150mA (I ), Constant Off-Time,
V
= 1.2V to 15V, V
= 34V, I = 20µA, I = <1µA,
Q SD
SW
IN
High Efficiency Step-Up DC/DC Converter
MS Package
Dual Output, ±350mA (I ), Constant Off-Time,
V
= 1.2V to 15V, V
= ±34V, I = 20µA, I = <1µA,
Q SD
SW
IN
High Efficiency Step-Up DC/DC Converter
MS Package
V = 2.7V to 4.5V, I = 8mA, I = <1µA,
IN
MS, ThinSOT Packages, Up to 6 White LEDs
V = 2.7V to 4.5V, I = 6.5mA, I = <1µA,
IN
MS Package, Up to 6 White LEDs
V = 2.7V to 4.5V, I = 5mA, I = <1µA,
IN
MS Package, Up to 8 White LEDs
V = 0.85V to 5V, V = 5V, I = 19µA/300µA, I = <1µA,
IN
LTC3200/
LTC3200-5
Low Noise, 2MHz, Regulated Charge Pump
White LED Driver
Q
SD
LTC3201
LTC3202
Low Noise, 1.7MHz, Regulated Charge Pump
White LED Driver
Q
SD
Low Noise, 1.5MHz, Regulated Charge Pump
White LED Driver
Q
SD
LTC3400/
LTC3400B
600mA (I ), 1.2MHz, Synchronous
SW
OUT(MAX)
Q
SD
Step-Up DC/DC Converter
ThinSOT Package
LTC3401
1A (I ), 3MHz, Synchronous
Step-Up DC/DC Converter
V
= 0.5V to 5V, V
= 6V, I = 38µA, I = <1µA,
Q SD
SW
IN
OUT(MAX)
OUT(MAX)
MS Package
LTC3402
2A (I ), 3MHz, Synchronous
V
= 0.5V to 5V, V
= 6V, I = 38µA, I = <1µA,
Q SD
SW
IN
Step-Up DC/DC Converter
MS Package
3464f
LT/TP 0204 1K • PRINTED IN USA
16 LinearTechnology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
●
●
LINEAR TECHNOLOGY CORPORATION 2003
(408) 432-1900 FAX: (408) 434-0507 www.linear.com
相关型号：
LTGLO400-TB-B-R/125N
Rocker Switch, DPST, Latched, Solder Terminal, Rocker Actuator, Panel Mount
Carling Techn
LTGLO400-TB-B-R/250N
Rocker Switch, DPST, Latched, Solder Terminal, Rocker Actuator, Panel Mount
Carling Techn
LTGLO400-TB-B-R/28V
Rocker Switch, DPST, Latched, Solder Terminal, Rocker Actuator, Panel Mount
Carling Techn
LTGLO400-TB-B-R/6V
Rocker Switch, DPST, Latched, Solder Terminal, Rocker Actuator, Panel Mount
Carling Techn
©2020 ICPDF网 联系我们和版权申明