1
LT1613
1.4MHz, Single Cell DC/DC
Converter in 5-Lead SOT-23
■
Uses Tiny Capacitors and Inductor
■
Internally Compensated
■
Fixed Frequency 1.4MHz Operation
■
Operates with V
IN
as Low as 1.1V
■
3V at 30mA from a Single Cell
■
5V at 200mA from 3.3V Input
■
15V at 60mA from Four Alkaline Cells
■
High Output Voltage: Up to 34V
■
Low Shutdown Current: <1µA
■
Low V
CESAT
Switch: 300mV at 300mA
■
Tiny 5-Lead SOT-23 Package
The LT
®
1613 is the industry’s first 5-lead SOT-23 current
mode DC/DC converter. Intended for small, low power
applications, it operates from an input voltage as low as
1.1V and switches at 1.4MHz, allowing the use of tiny, low
cost capacitors and inductors 2mm or less in height. Its
small size and high switching frequency enables the
complete DC/DC converter function to take up less than
0.2 square inches of PC board area. Multiple output power
supplies can now use a separate regulator for each output
voltage, replacing cumbersome quasi-regulated ap-
proaches using a single regulator and a custom trans-
former.
A constant frequency, internally compensated current
mode PWM architecture results in low, predictable output
noise that is easy to filter. The high voltage switch on the
LT1613 is rated at 36V, making the device ideal for boost
converters up to 34V as well as for Single-Ended Primary
Inductance Converter (SEPIC) and flyback designs. The
device can generate 5V at up to 200mA from a 3.3V supply
or 5V at 175mA from four alkaline cells in a SEPIC design.
The LT1613 is available in the 5-lead SOT-23 package.
■
Digital Cameras
■
Pagers
■
Cordless Phones
■
Battery Backup
■
LCD Bias
■
Medical Diagnostic Equipment
■
Local 5V or 12V Supply
■
External Modems
■
PC Cards
Efficiency Curve
LOAD CURRENT (mA)
0 50 100 150 200 250 300 350 400
EFFICIENCY (%)
1613 TA01a
100
95
90
85
80
75
70
65
60
55
50
V
IN
= 4.2V
V
IN
= 3.5V
V
IN
= 2.8V
V
IN
= 1.5V
Figure 1. 3.3V to 5V 200mA DC/DC Converter
V
IN
V
IN
3.3V V
OUT
5V
200mA
1613 TA01
SW
L1
4.7µHD1
GND
LT1613
L1: MURATA LQH3C4R7M24 OR SUMIDA CD43-4R7
C1: AVX TAJA156M010
C2: AVX TAJB226M006
D1: MBR0520
C1
15µFC2
22µF
R2
12.1k
R1
37.4k
FBSHDN SHDN
+ +
, LTC and LT are registered trademarks of Linear Technology Corporation.
APPLICATIO S
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FEATURES
TYPICAL APPLICATIO
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DESCRIPTIO
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2
LT1613
PARAMETER CONDITIONS MIN TYP MAX UNITS
Minimum Operating Voltage 0.9 1.1 V
Maximum Operating Voltage 10 V
Feedback Voltage ●1.205 1.23 1.255 V
FB Pin Bias Current ●27 80 nA
Quiescent Current V
SHDN
= 1.5V 3 4.5 mA
Quiescent Current in Shutdown V
SHDN
= 0V, V
IN
= 2V 0.01 0.5 µA
V
SHDN
= 0V, V
IN
= 5V 0.01 1.0 µA
Reference Line Regulation 1.5V ≤ V
IN
≤ 10V 0.02 0.2 %/V
Switching Frequency ●1.0 1.4 1.8 MHz
Maximum Duty Cycle ●82 86 %
Switch Current Limit (Note 3) 550 800 mA
Switch V
CESAT
I
SW
= 300mA 300 350 mV
Switch Leakage Current V
SW
= 5V 0.01 1 µA
SHDN Input Voltage High 1V
SHDN Input Voltage Low 0.3 V
SHDN Pin Bias Current V
SHDN
= 3V 25 50 µA
V
SHDN
= 0V 0.01 0.1 µA
(Note 1)
V
IN
Voltage .............................................................. 10V
SW Voltage ................................................–0.4V to 36V
FB Voltage ..................................................... V
IN
+ 0.3V
Current into FB Pin ............................................... ±1mA
SHDN Voltage .......................................................... 10V
Maximum Junction Temperature .......................... 125°C
Operating Temperature Range
Commercial ............................................. 0°C to 70°C
Extended Commercial (Note 2)........... –40°C to 85°C
Storage Temperature Range ................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec)..................300°C
ABSOLUTE MAXIMUM RATINGS
W
WW
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PACKAGE/ORDER INFORMATION
W
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S5 PART MARKING
LTED
ORDER PART NUMBER
LT1613CS5
SW 1
GND 2
TOP VIEW
S5 PACKAGE
5-LEAD PLASTIC SOT-23
FB 3
5 V
IN
4 SHDN
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. Commercial grade 0°C to 70°C, VIN = 1.5V, VSHDN = VIN unless
otherwise noted. (Note 2)
Consult factory for Industrial and Military grade parts.
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired. Note 2: The LT1613C 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 3: Current limit guaranteed by design and/or correlation to static test.
3
LT1613
TYPICAL PERFOR A CE CHARACTERISTICS
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SWITCH CURRENT (mA)
0 100 200 300 400 500 600 700
V
CESAT
(mV)
1613 G01
700
600
500
400
300
200
100
0
T
A
= 25°C
TEMPERATURE (°C)
–50 –25 0 25 50 75 100
SWITCHING FREQUENCY (MHz)
1613 G02
2.00
1.75
1.50
1.25
1.00
0.75
0.50
0.25
0
V
IN
= 5V
V
IN
= 1.5V
SHDN PIN VOLTAGE (V)
012345
SHDN PIN BIAS CURRENT (µA)
1613 G03
50
40
30
20
10
0
TA = 25°C
DUTY CYCLE (%)
10 20 30 40 50 60 70 80
CURRENT LIMIT (mA)
1613 G04
1000
900
800
700
600
500
400
300
200
70°C
25°C
–40°C
TEMPERATURE (°C)
–50
FEEDBACK PIN VOLTAGE (V)
1613 G05
1.25
1.24
1.23
1.22
1.21
1.20
VOLTAGE
–25 0 25 50 75 100
Switch VCESAT vs Switch Current SHDN Pin Current vs VSHDN
Oscillator Frequency vs
Temperature
Current Limit vs Duty Cycle Feedback Pin Voltage
Switching Waveforms, Circuit of Figure 1
V
OUT
100mV/DIV
AC COUPLED
V
SW
5V/DIV
I
SW
200mA/DIV
I
LOAD
= 150mA 200ns/DIV 1613 G06
4
LT1613
PIN FUNCTIONS
UUU
SW (Pin 1): Switch Pin. Connect inductor/diode here.
Minimize trace area at this pin to keep EMI down.
GND (Pin 2): Ground. Tie directly to local ground plane.
FB (Pin 3): Feedback Pin. Reference voltage is 1.23V.
Connect resistive divider tap here. Minimize trace area at
FB. Set V
OUT
according to V
OUT
= 1.23V(1 + R1/R2).
SHDN (Pin 4): Shutdown Pin. Tie to 1V or more to enable
device. Ground to shut down.
V
IN
(Pin 5): Input Supply Pin. Must be locally bypassed.
BLOCK DIAGRAM
W
–
+
–
+
FF
RQ
S
0.15Ω
SW
DRIVER
COMPARATOR
2
SHUTDOWN
SHDN
4
1
–
+
Σ
RAMP
GENERATOR
R
C
C
C
1.4MHz
OSCILLATOR
GND
1613 • BD
R6
40k
R4
140k
R3
30k
Q2
x10
Q1
Q3
R2
(EXTERNAL)
R1
(EXTERNAL)
R5
40k
V
OUT
V
IN
V
IN
5
FB
FB 3
A2
A1
g
m
The LT1613 is a current mode, internally compensated,
fixed frequency step-up switching regulator. Operation
can be best understood by referring to the Block Diagram.
Q1 and Q2 form a bandgap reference core whose loop is
closed around the output of the regulator. The voltage
drop across R5 and R6 is low enough such that Q1 and Q2
do not saturate, even when V
IN
is 1V. When there is no
load, FB rises slightly above 1.23V, causing V
C
(the error
amplifier’s output) to decrease. Comparator A2’s output
stays high, keeping switch Q3 in the off state. As increased
output loading causes the FB voltage to decrease, A1’s
output increases. Switch current is regulated directly on a
cycle-by-cycle basis by the V
C
node. The flip flop is set at
the beginning of each switch cycle, turning on the switch.
When the summation of a signal representing switch
current and a ramp generator (introduced to avoid
OPERATIO
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subharmonic oscillations at duty factors greater than
50%) exceeds the V
C
signal, comparator A2 changes
state, resetting the flip flop and turning off the switch.
More power is delivered to the output as switch current is
increased. The output voltage, attenuated by external
resistor divider R1 and R2, appears at the FB pin, closing
the overall loop. Frequency compensation is provided
internally by R
C
and C
C
. Transient response can be opti-
mized by the addition of a phase lead capacitor C
PL
in
parallel with R1 in applications where large value or low
ESR output capacitors are used.
As the load current is decreased, the switch turns on for a
shorter period each cycle. If the load current is further
decreased, the converter will skip cycles to maintain
output voltage regulation.
5
LT1613
OPERATIO
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LAYOUT
The LT1613 switches current at high speed, mandating
careful attention to layout for proper performance.
You
will not get advertised performance with careless layouts.
Figure 2 shows recommended component placement for
a boost (step-up) converter. Follow this closely in your
PCB layout. Note the direct path of the switching loops.
Input capacitor C1
must
be placed close (<5mm) to the IC
package. As little as 10mm of wire or PC trace from C
IN
to
V
IN
will cause problems such as inability to regulate or
oscillation.
The ground terminal of output capacitor C2 should tie
close to Pin 2 of the LT1613. Doing this reduces dI/dt in the
ground copper which keeps high frequency spikes to a
minimum. The DC/DC converter ground should tie to the
PC board ground plane at one place only, to avoid intro-
ducing dI/dt in the ground plane.
A SEPIC (single-ended primary inductance converter)
schematic is shown in Figure 3. This converter topology
produces a regulated output voltage that spans (i.e., can
be higher or lower than) the output. Recommended com-
ponent placement for a SEPIC is shown in Figure 4.
D1
1613 F02
GROUND
VIAS TO
GROUND
PLANE
SHUTDOWN
V
IN
L1
V
OUT
R2
R1
+
C2
+
C1
15
2
34
Figure 2. Recommended Component Placement for Boost
Converter. Note Direct High Current Paths Using Wide PCB
Traces. Minimize Area at Pin 3 (FB). Use Vias to Tie Local
Ground Into System Ground Plane. Use Vias at Location Shown
to Avoid Introducing Switching Currents Into Ground Plane
VIN
VOUT
5V/150mA
1613 F03
SW
L1A
22µH
L1B
22µHD1
GND
LT1613
C1, C2: AVX TAJA156M016
C3: TAIYO YUDEN JMK325BJ226MM
D1: MOTOROLA MBR0520
L1, L2: MURATA LQH3C220
R2
32.4k
R1
100k
C3
1µF
FBSHDN
C1
15µF
VIN
4V TO
7V
+
C2
15µF
+
SHDN
Figure 3. Single-Ended Primary Inductance Converter (SEPIC)
Generates 5V from An Input Voltage Above or Below 5V
D1
C3
1613 F04
GROUND
VIAS TO
GROUND
PLANE
SHUTDOWN
V
IN
L1AL1B
V
OUT
R2
R1
+
C2
+
C1
15
2
34
Figure 4. Recommended Component Placement for SEPIC
COMPONENT SELECTION
Inductors
Inductors used with the LT1613 should have a saturation
current rating (where inductance is approximately 70% of
zero current inductance) of approximately 0.5A or greater.
DCR of the inductors should be 0.5Ω or less. For boost
converters, inductance should be 4.7µH for input voltage
less than 3.3V and 10µH for inputs above 3.3V. When
using the device as a SEPIC, either a coupled inductor or
two separate inductors can be used. If using separate
inductors, 22µH units are recommended for input voltage
above 3.3V. Coupled inductors have a beneficial mutual
inductance, so a 10µH coupled inductor results in the
same ripple current as two 20µH uncoupled units.
6
LT1613
OPERATIO
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Table 1 lists several inductors that will work with the
LT1613, although this is not an exhaustive list. There are
many magnetics vendors whose components are suitable
for use.
Diodes
A Schottky diode is recommended for use with the LT1613.
The Motorola MBR0520 is a very good choice. Where the
input to output voltage differential exceeds 20V, use the
MBR0530 (a 30V diode). If cost is more important than
efficiency, the 1N4148 can be used, but only at low current
loads.
Capacitors
The input bypass capacitor must be placed physically
close to the input pin. ESR is not critical and in most cases
an inexpensive tantalum is appropriate.
The choice of output capacitor is far more important. The
quality of this capacitor is the greatest determinant of the
output voltage ripple. The output capacitor must have
enough capacitance to satisfy the load under transient
conditions and it must shunt the switched component of
current coming through the diode. Output voltage ripple
results when this switched current passes through the
finite output impedance of the output capacitor. The
capacitor should have low impedance at the 1.4MHz
switching frequency of the LT1613. At this frequency, the
impedance is usually dominated by the capacitor’s equiva-
lent series resistance (ESR). Choosing a capacitor with
lower ESR will result in lower output ripple.
Ceramic capacitors can be used with the LT1613 provided
loop stability is considered. A tantalum capacitor has
some ESR and this causes an “ESR zero” in the regulator
loop. This zero is beneficial to loop stability. The internally
compensated LT1613 does not have an accessible com-
pensation node, but other circuit techniques can be em-
ployed to counteract the loss of the ESR zero, as detailed
in the next section.
Some capacitor types appropriate for use with the LT1613
are listed in Table 2.
OPERATION WITH CERAMIC CAPACITORS
Because the LT1613 is internally compensated, loop sta-
bility must be carefully considered when choosing an
output capacitor. Small, low cost tantalum capacitors
have some ESR, which aids stability. However, ceramic
capacitors are becoming more popular, having attractive
characteristics such as near-zero ESR, small size and
reasonable cost. Simply replacing a tantalum output ca-
pacitor with a ceramic unit will decrease the phase margin,
in some cases to unacceptable levels. With the addition of
a phase lead capacitor (C
PL
) and isolating resistor (R3),
the LT1613 can be used successfully with ceramic output
capacitors as described in the following figures.
A boost converter, stepping up 2.5V to 5V, is shown in
Figure 5. Tantalum capacitors are used for the input and
output (the input capacitor is not critical and has little
Table 1. Inductor Vendors
VENDOR PHONE URL PART COMMENT
Sumida (847) 956-0666 www.sumida.com CLS62-22022 22µH Coupled
CD43-220 22µH
Murata (404) 436-1300 www.murata.com LQH3C-220 22µH, 2mm Height
LQH3C-100 10µH
LQH3C-4R7 4.7µH
Coiltronics (407) 241-7876 www.coiltronics.com CTX20-1 20µH Coupled, Low DCR
Table 2. Capacitor Vendors
VENDOR PHONE URL PART COMMENT
Taiyo Yuden (408) 573-4150 www.t-yuden.com Ceramic Caps X5R Dielectric
AVX (803) 448-9411 www.avxcorp.com Ceramic Caps
Tantalum Caps
Murata (404) 436-1300 www.murata.com Ceramic Caps
7
LT1613
OPERATIO
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resulting in a severely underdamped response. By adding
R3 and C
PL
as detailed in Figure 8’s schematic, phase
margin is restored, and transient response to the same
load step is pictured in Figure 9. R3 isolates the device FB
pin from fast edges on the V
OUT
node due to parasitic PC
trace inductance.
Figure 10’s circuit details a 5V to 12V boost converter,
delivering up to 130mA. The transient response to a load
step of 10mA to 130mA, without C
PL
, is pictured in
Figure␣ 11. Although the ringing is less than that of the
previous example, the response is still underdamped and
can be improved. After adding R3 and C
PL
, the improved
transient response is detailed in Figure 12.
Figure 13 shows a SEPIC design, converting a 3V to 10V
input to a 5V output. The transient response to a load step
of 20mA to 120mA, without C
PL
and R3, is pictured in
Figure␣ 14. After adding these two components, the im-
proved response is shown in Figure 15.
effect on loop stability, as long as minimum capacitance
requirements are met). The transient response to a load
step of 50mA to 100mA is pictured in Figure 6. Note the
“double trace,” due to the ESR of C2. The loop is stable and
settles in less than 100µs. In Figure 7, C2 is replaced by a
10µF ceramic unit. Phase margin decreases drastically,
V
IN
V
OUT
5V
1613 F05
SW
L1
10µHD1
GND
LT1613
C1: AVX TAJA156M010R
C2: AVX TAJA226M006R
D1: MOTOROLA MBR0520
L1: MURATA LQH3C100
R2
12.1k
R1
37.4k
FBSHDN
C1
15µF
V
IN
2.5V
+
C2
22µF
+
SHDN
Figure 5. 2.5V to 5V Boost Converter with “A”
Case Size Tantalum Input and Output Capacitors
V
IN
V
OUT
5V
C
PL
330pF
1613 F08
SW
L1
10µHD1
GND
LT1613
C1: AVX TAJA156M010R
C2: TAIYO YUDEN LMK325BJ106MN
D1: MBR0520
L1: MURATA LQH3C100K04
R2
12.1k
R3
10k
R1
37.4k
FBSHUTDOWN
C1
15µF
V
IN
2.5V
C2
10µF
SHDN
+
V
OUT
20mV/DIV
AC COUPLED
LOAD CURRENT 100mA
50mA
200µs/DIV 1613 F06
Figure 6. 2.5V to 5V Boost Converter Transient
Response with 22µF Tantalum Output Capacitor.
Apparent Double Trace on VOUT Is Due to Switching
Frequency Ripple Current Across Capacitor ESR
V
OUT
20mV/DIV
AC COUPLED
LOAD CURRENT 100mA
200µs/DIV 1613 F07
50mA
Figure 7. 2.5V to 5V Boost Converter with
10µF Ceramic Output Capacitor, No CPL
Figure 8. 2.5V to 5V Boost Converter with Ceramic
Output Capacitor. CPL Added to Increase Phase Margin,
R3 Isolates FB Pin from Fast Edges
V
OUT
20mV/DIV
AC COUPLED
LOAD CURRENT 100mA
200µs/DIV 1613 F09
50mA
Figure 9. 2.5V to 5V Boost Converter with 10µF Ceramic
Output Capacitor, 330pF CPL and 10k in Series with FB Pin
8
LT1613
OPERATIO
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V
IN
V
OUT
12V
130mA
C
PL
200pF
1613 F10
SW
L1
10µHD1
GND
LT1613
C1: AVX TAJB226M010
C2: TAIYO YUDEN EMK325BJ475MN
D1: MOTOROLA MBR0520
L1: MURATA LQH3C100
R2
12.3k
R3
10k
R1
107k
FBSHUTDOWN
C1
22µF
V
IN
5V
C2
4.7µF
SHDN
+
Figure 10. 5V to 12V Boost Converter with 4.7µF Ceramic
Output Capacitor, CPL Added to Increase Phase Margin
V
OUT
100mV/DIV
AC COUPLED
LOAD CURRENT 130mA
200µs/DIV 1613 F11
10mA
Figure 11. 5V to 12V Boost Converter
with 4.7µF Ceramic Output Capacitor
V
IN
V
OUT
5V
1613 F13
SW
L1
22µH
L2
22µHC
PL
330pF D1
GND
LT1613
C1: AVX TAJB226M010
C2: TAIYO YUDEN LMK325BJ106MN
C3: TAIYO YUDEN LMK212BJ105MG
D1: MOTOROLA MBR0520
L1, L2: MURATA LQH3C220
R2
12.1k
R1
37.4k
R3
10k
C3
1µF
FBSHUTDOWN
C1
22µF
V
IN
3V TO
10V
C2
10µF
SHDN
+
V
OUT
100mV/DIV
AC COUPLED
LOAD CURRENT 130mA
200µs/DIV 1613 F12
10mA
Figure 12. 5V to 12V Boost Converter with 4.7µF
Ceramic Output Capacitor and 200pF Phase-Lead
Capacitor CPL and 10k in Series with FB Pin
Figure 13. 5V Output SEPIC with Ceramic
Output Capacitor. CPL Adds Phase Margin
V
OUT
50mV/DIV
AC COUPLED
LOAD CURRENT 120mA
200µs/DIV 1613 F14
20mA
Figure 14. 5V Output SEPIC with 10µF
Ceramic Output Capacitor. No CPL. VIN = 4V
V
OUT
50mV/DIV
AC COUPLED
LOAD CURRENT 120mA
200µs/DIV 1613 F15
20mA
Figure 15. 5V Output SEPIC with 10µF Ceramic Output
Capacitor, 330pF CPL and 10k in Series with FB Pin
9
LT1613
START-UP/SOFT-START
When the LT1613 SHDN pin voltage goes high, the device
rapidly increases the switch current until internal current
limit is reached. Input current stays at this level until the
output capacitor is charged to final output voltage. Switch
current can exceed 1A. Figure 16’s oscillograph details
start-up waveforms of Figure 17’s SEPIC into a 50Ω load
without any soft-start. The output voltage reaches final
value in approximately 200µs, while input current reaches
400mA. Switch current in a SEPIC is 2x the input current,
so the switch is conducting approximately 800mA peak.
Soft-start reduces the inrush current by taking more time
to reach final output voltage. A soft-start circuit consisting
of Q1, R
S1
, R
S2
and C
S1
as shown in Figure 17 can be used
to limit inrush current to a lower value. Figure 18 pictures
V
OUT
and input current with R
S2
of 33kΩ and C
S
of 10nF.
Input current is limited to a peak value of 200mA as the
OPERATIO
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V
IN
V
OUT
5V
1613 F17
SW
L1
22µH
L2
22µHC
PL
330pF D1
GND
LT1613
C1: AVX TAJB226M006
C2: TAIYO YUDEN LMK325BJ106MN
C3: TAIYO YUDEN LMK212BJ105MG
R2
12.1k R
LOAD
Q1
2N3904
R1
37.4k
R3
10k
R
S1
33k
C3
1µF
FBV
S
SOFT-START COMPONENTS
C1
22µF
V
IN
4V
C2
10µF
SHDN
+
R
S2
33k
C
S
10nF/
33nF
D1: MOTOROLA MBR0520
L1, L2: MURATA LQH3C220
time required to reach final value increases to 1.7ms. In
Figure 19, C
S
is increased to 33nF. Input current does not
exceed the steady-state current the device uses to supply
power to the 50Ω load. Start-up time increases to 4.3ms.
C
S
can be increased further for an even slower ramp, if
desired.
V
OUT
2V/DIV
200µs/DIV 1613 F16
Figure 16. Start-Up Waveforms of
Figure 17’s SEPIC Into 50Ω Load
I
IN
200mA/DIV
V
SHDN
5V/DIV
V
OUT
2V/DIV
500µs/DIV 1613 F18
Figure 18. Soft-Start Components in Figure 17’s SEPIC
Reduces Inrush Current. CSS = 10nF, RLOAD = 50Ω
I
IN
200mA/DIV
V
S
5V/DIV
V
OUT
2V/DIV
1ms/DIV 1613 F18
Figure 19. Increasing CS to 33nF Further
Reduces Inrush Current. RLOAD = 50Ω
I
IN
200mA/DIV
V
S
5V/DIV
Figure 17. 5V SEPIC with Soft-Start Components
10
LT1613
TYPICAL APPLICATIO S
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V
IN
V
OUT
5V
175mA
1613 • TA03
SW
L1
22µH
L2
22µH
C3
1µFD1
GND
LT1613
L1, L2: MURATA LQH3C220
C3: AVX 1206YG105 CERAMIC
D1: MBR0520
C2
22µF
121k
374k
FBSHDN
C1
15µF
6.5V TO 4V
SHDN
+
+
4-CELL
4-Cell to 5V SEPIC DC/DC Converter
V
IN
V
OUT
15V/30mA
1613 TA04
SW
L1
10µHD1
GND
LT1613
C1: AVX TAJB226M016
C2: AVX TAJA475M025
D1: MOTOROLA MBR0520
L1: MURATA LQH3C100
R2
12.1k
R1
137k
1%
10k
FBSHDN
C1
22µF
V
IN
3.5V TO
8V
+
C2
4.7µF
+
SHDN
1nF
LOAD CURRENT (mA)
0 102030405060708090100
EFFICIENCY (%)
1613 TA04a
85
80
75
70
65
60
55
50
V
IN
= 6.5V
V
IN
= 5V
V
IN
= 3.6V
D1
D4
0.22µF
L1
5.4µH
0.22µF
48.7k
1613 TA05
274k
C1
4.7µF
V
IN
3.3V
C2
4.7µF
1µF
1µF
1µF
0.22µF
AV
DD
8V
70mA
0.22µF: TAIYO YUDEN EMK212BJ224MG
1µF: TAIYO YUDEN LMK212BJ105MG
4.7µF: TAIYO YUDEN LMK316BJ475ML
D1: MOTOROLA MBRO520
D2, D3, D4: BAT54S
L1: SUMIDA CDRH5D185R4
V
ON
24V
5mA
V
OFF
–8V
5mA
D3
D2
V
IN
SW
GND
LT1613
FBSHDN
4-Cell to 15V/30mA DC/DC Converter
Efficiency
3.3V to 8V/70mA, –8V/5mA, 24V/5mA TFT LCD Bias Supply Uses All Ceramic Capacitors
11
LT1613
TYPICAL APPLICATIO S
U
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 of its circuits as described herein will not infringe on existing patent rights.
33.2k
1613 TA08
102k
V
IN
7V TO 3.6V
270pF
C2
1µF
C1: TAIYO YUDEN JMK316BJ106ML
C2, C3, C4: TAIYO YUDEN EMK212BJ105MG
C5: TAIYO YUDEN JMK212BJ475MG
D1: MOTOROLA MBR0520
D2, D3: BAT54
T1: COILCRAFT CCI8244A (847) 639-6400
V
IN
SW
GND
LT1613
FBSHDN
SHUTDOWN
C1
10µF
C4
1µF
D3
3
4
6
T1
1
5
2
D1
D2
C5
4.7µF
C3
1µF
15V/10mA
5V/50mA
–7.5V/10mA
33.2k
1613 TA07
102k
V
IN
7V TO 3.6V
270pF
C2
1µF
C1: TAIYO YUDEN JMK316BJ106ML
C2, C3, C4: TAIYO YUDEN EMK212BJ105MG
C5: TAIYO YUDEN JMK212BJ475MG
D1: MOTOROLA MBR0520
D2, D3: BAT54
T1: COILCRAFT CCI8245A (847) 639-6400
V
IN
SW
GND
LT1613
FBSHDN
SHUTDOWN
C1
10µF
C5
4.7µF
D1
3
4
6
T1
1
5
2
D2
D3
C4
1µF
C3
1µF
15V/10mA
12V/10mA
5V/50mA
4-Cell to 5V/50mA, 12V/10mA, 15V/10mA Digital Camera Power Supply
4-Cell to 5V/50mA, 15V/10mA, –7.5V/10mA Digital Camera Power Supply
12
LT1613
sn1613 1613fs LT/TP 1299 4K • PRINTED IN USA
L INEAR TECHNO LOGY CORPO R AT IO N 1997
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507
●
www.linear-tech.com
TYPICAL APPLICATIONS
U
PACKAGE DESCRIPTION
U
Dimensions in inches (millimeters) unless otherwise noted.
S5 Package
5-Lead Plastic SOT-23
(LTC DWG # 05-08-1633)
RELATED PARTS
PART NUMBER DESCRIPTION COMMENTS
LT1307 Single Cell Micropower DC/DC 3.3V/75mA From 1V; 600kHz Fixed Frequency
LT1317 2-Cell Micropower DC/DC 3.3V/200mA From Two Cells; 600kHz Fixed Frequency
LTC1474 Low Quiescent Current, High Efficiency Step-Down Converter 94% Efficiency, 10µA I
Q
, 9V to 5V at 250µA
LT1521 300mA Low Dropout Regulator with Micropower Quiescent 500mV Dropout, 300mA Output Current, 12µA I
Q
Current and Shutdown
LTC1517-5 Micropower, Regulated Charge Pump 3-Cells to 5V at 20mA, SOT-23 Package, 6µA I
Q
LT1610 1.7MHz Single Cell Micropower DC/DC Converter 30µA I
Q
, MSOP Package, Internal Compensation
LT1611 Inverting 1.4MHz Switching Regulator 5V to –5V at 150mA, Low Output Noise
LT1615/LT1615-1 Micropower DC/DC Converter in 5-Lead SOT-23 20V at 12mA from 2.5V Input, Tiny SOT-23 Package
VIN
16V
20mA
1613 TA06
SW
L1
2.2µHD1
GND
LT1613
C1: AVX TAJA4R7M010
C2: TAIYO YUDEN LMK212BJ105MG
D1: BAT54S DUAL DIODE
L1: MURATA LQH3C2R2
13.7k
1%
165k
1%
FBSHDN
C1
4.7µF
VIN
2.7V
TO 4.5V
C2
1µF
X5R
CERAMIC
SHDN
+
1.50 – 1.75
(0.059 – 0.069)
0.35 – 0.55
(0.014 – 0.022) 0.35 – 0.50
(0.014 – 0.020)
FIVE PLACES (NOTE 2)
S5 SOT-23 0599
0.90 – 1.45
(0.035 – 0.057)
0.90 – 1.30
(0.035 – 0.051)
0.00 – 0.15
(0.00 – 0.006)
0.09 – 0.20
(0.004 – 0.008)
(NOTE 2)
2.60 – 3.00
(0.102 – 0.118)
NOTE:
1. DIMENSIONS ARE IN MILLIMETERS
2. DIMENSIONS ARE INCLUSIVE OF PLATING
3. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR
4. MOLD FLASH SHALL NOT EXCEED 0.254mm
5. PACKAGE EIAJ REFERENCE IS SC-74A (EIAJ)
0.95
(0.037)
REF
2.80 – 3.00
(0.110 – 0.118)
(NOTE 3)
1.90
(0.074)
REF
Li-Ion to 16V/20mA Step-Up DC/DC Converter
