LT1613

1.4MHz, Single Cell DC/DC

Converter in 5-Lead SOT-23
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FEATURES DESCRIPTIO
■ Uses Tiny Capacitors and Inductor The LT®1613 is the industry’s first 5-lead SOT-23 current
■ Internally Compensated mode DC/DC converter. Intended for small, low power
■ Fixed Frequency 1.4MHz Operation applications, it operates from an input voltage as low as
■ Operates with VIN as Low as 1.1V 1.1V and switches at 1.4MHz, allowing the use of tiny, low
■ 3V at 30mA from a Single Cell cost capacitors and inductors 2mm or less in height. Its
■ 5V at 200mA from 3.3V Input small size and high switching frequency enables the
■ 15V at 60mA from Four Alkaline Cells complete DC/DC converter function to take up less than
■ High Output Voltage: Up to 34V 0.2 square inches of PC board area. Multiple output power
■ Low Shutdown Current: <1µA supplies can now use a separate regulator for each output
■ Low VCESAT Switch: 300mV at 300mA voltage, replacing cumbersome quasi-regulated ap-
■ Tiny 5-Lead SOT-23 Package proaches using a single regulator and a custom trans-
former.
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APPLICATIO S A constant frequency, internally compensated current
mode PWM architecture results in low, predictable output
■ Digital Cameras noise that is easy to filter. The high voltage switch on the
■ Pagers LT1613 is rated at 36V, making the device ideal for boost
■ Cordless Phones converters up to 34V as well as for Single-Ended Primary
■ Battery Backup Inductance Converter (SEPIC) and flyback designs. The
■ LCD Bias device can generate 5V at up to 200mA from a 3.3V supply
■ Medical Diagnostic Equipment or 5V at 175mA from four alkaline cells in a SEPIC design.
■ Local 5V or 12V Supply
■ External Modems The LT1613 is available in the 5-lead SOT-23 package.
, LTC and LT are registered trademarks of Linear Technology Corporation.
■ PC Cards

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TYPICAL APPLICATIO
L1
D1
Efficiency Curve
4.7µH
VIN VOUT 100
3.3V 5V
95
200mA
VIN SW R1
90 VIN = 4.2V
37.4k
+ C1 + C2 85
15µF LT1613 22µF
EFFICIENCY (%)

80
SHDN SHDN FB VIN = 3.5V
75
GND R2 VIN = 2.8V
12.1k 70
65
L1: MURATA LQH3C4R7M24 OR SUMIDA CD43-4R7 VIN = 1.5V
60
C1: AVX TAJA156M010
C2: AVX TAJB226M006 1613 TA01 55
D1: MBR0520
50
0 50 100 150 200 250 300 350 400
Figure 1. 3.3V to 5V 200mA DC/DC Converter
LOAD CURRENT (mA)
1613 TA01a

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ABSOLUTE MAXIMUM RATINGS PACKAGE/ORDER INFORMATION
(Note 1)
VIN Voltage .............................................................. 10V ORDER PART NUMBER
SW Voltage ................................................– 0.4V to 36V LT1613CS5
TOP VIEW
FB Voltage ..................................................... VIN + 0.3V
Current into FB Pin ............................................... ±1mA SW 1 5 VIN

SHDN Voltage .......................................................... 10V GND 2

FB 3 4 SHDN
Maximum Junction Temperature .......................... 125°C
S5 PART MARKING
Operating Temperature Range S5 PACKAGE
5-LEAD PLASTIC SOT-23
Commercial ............................................. 0°C to 70°C LTED
Extended Commercial (Note 2) ........... – 40°C to 85°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
Consult factory for Industrial and Military grade parts.

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)

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 VSHDN = 1.5V 3 4.5 mA
Quiescent Current in Shutdown VSHDN = 0V, VIN = 2V 0.01 0.5 µA
VSHDN = 0V, VIN = 5V 0.01 1.0 µA
Reference Line Regulation 1.5V ≤ VIN ≤ 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 VCESAT ISW = 300mA 300 350 mV
Switch Leakage Current VSW = 5V 0.01 1 µA
SHDN Input Voltage High 1 V
SHDN Input Voltage Low 0.3 V
SHDN Pin Bias Current VSHDN = 3V 25 50 µA
VSHDN = 0V 0.01 0.1 µA

Note 1: Absolute Maximum Ratings are those values beyond which the life Note 2: The LT1613C is guaranteed to meet performance specifications
of a device may be impaired. 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.

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 LT1613
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TYPICAL PERFOR A CE CHARACTERISTICS
Oscillator Frequency vs
Switch VCESAT vs Switch Current Temperature SHDN Pin Current vs VSHDN
700 2.00 50
TA = 25°C TA = 25°C
600 1.75 VIN = 5V

SWITCHING FREQUENCY (MHz)

SHDN PIN BIAS CURRENT (µA)

40
1.50
500
VIN = 1.5V
1.25
VCESAT (mV)

30
400
1.00
300
0.75 20

200
0.50
10
100 0.25

0 0 0
0 100 200 300 400 500 600 700 –50 –25 0 25 50 75 100 0 1 2 3 4 5
SWITCH CURRENT (mA) TEMPERATURE (°C) SHDN PIN VOLTAGE (V)
1613 G01 1613 G02 1613 G03

Current Limit vs Duty Cycle Feedback Pin Voltage

1000 1.25

900
1.24
FEEDBACK PIN VOLTAGE (V)

800
CURRENT LIMIT (mA)

70°C VOLTAGE
700
1.23
600 25°C

500 1.22
–40°C
400
1.21
300

200 1.20
10 20 30 40 50 60 70 80 –50 –25 0 25 50 75 100
DUTY CYCLE (%) TEMPERATURE (°C)
1613 G04 1613 G05

Switching Waveforms, Circuit of Figure 1

VOUT
100mV/DIV
AC COUPLED

VSW
5V/DIV

ISW
200mA/DIV

ILOAD = 150mA 200ns/DIV 1613 G06

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LT1613
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PIN FUNCTIONS
SW (Pin 1): Switch Pin. Connect inductor/diode here. SHDN (Pin 4): Shutdown Pin. Tie to 1V or more to enable
Minimize trace area at this pin to keep EMI down. device. Ground to shut down.
GND (Pin 2): Ground. Tie directly to local ground plane. VIN (Pin 5): Input Supply Pin. Must be locally bypassed.
FB (Pin 3): Feedback Pin. Reference voltage is 1.23V.
Connect resistive divider tap here. Minimize trace area at
FB. Set VOUT according to VOUT = 1.23V(1 + R1/R2).

W
BLOCK DIAGRAM
VIN 5 VIN

R5 R6
40k 40k
VOUT 1 SW
+ COMPARATOR
R1 A1 –
(EXTERNAL) gm DRIVER
FF
– A2 R Q Q3
FB RC + S
FB 3
Q1 Q2
RAMP
GENERATOR Σ
x10
CC +
R2 R3 0.15Ω
(EXTERNAL) 30k
1.4MHz –
OSCILLATOR
R4
140k
SHDN
4 SHUTDOWN 2 GND
1613 • BD

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OPERATIO
The LT1613 is a current mode, internally compensated, subharmonic oscillations at duty factors greater than
fixed frequency step-up switching regulator. Operation 50%) exceeds the VC signal, comparator A2 changes
can be best understood by referring to the Block Diagram. state, resetting the flip flop and turning off the switch.
Q1 and Q2 form a bandgap reference core whose loop is More power is delivered to the output as switch current is
closed around the output of the regulator. The voltage increased. The output voltage, attenuated by external
drop across R5 and R6 is low enough such that Q1 and Q2 resistor divider R1 and R2, appears at the FB pin, closing
do not saturate, even when VIN is 1V. When there is no the overall loop. Frequency compensation is provided
load, FB rises slightly above 1.23V, causing VC (the error internally by RC and CC. Transient response can be opti-
amplifier’s output) to decrease. Comparator A2’s output mized by the addition of a phase lead capacitor CPL in
stays high, keeping switch Q3 in the off state. As increased parallel with R1 in applications where large value or low
output loading causes the FB voltage to decrease, A1’s ESR output capacitors are used.
output increases. Switch current is regulated directly on a As the load current is decreased, the switch turns on for a
cycle-by-cycle basis by the VC node. The flip flop is set at shorter period each cycle. If the load current is further
the beginning of each switch cycle, turning on the switch. decreased, the converter will skip cycles to maintain
When the summation of a signal representing switch output voltage regulation.
current and a ramp generator (introduced to avoid

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OPERATIO
LAYOUT L1A
C3
1µF
VIN 22µH
4V TO
The LT1613 switches current at high speed, mandating 7V

careful attention to layout for proper performance. You + C1 VIN SW L1B

22µH D1
15µF
will not get advertised performance with careless layouts. LT1613 R1
100k
Figure 2 shows recommended component placement for SHDN SHDN FB
VOUT
5V/150mA
GND R2 +
a boost (step-up) converter. Follow this closely in your 32.4k
C2
15µF

PCB layout. Note the direct path of the switching loops. C1, C2: AVX TAJA156M016
Input capacitor C1 must be placed close (< 5mm) to the IC C3: TAIYO YUDEN JMK325BJ226MM
D1: MOTOROLA MBR0520
package. As little as 10mm of wire or PC trace from CIN to L1, L2: MURATA LQH3C220 1613 F03

VIN will cause problems such as inability to regulate or Figure 3. Single-Ended Primary Inductance Converter (SEPIC)
oscillation. Generates 5V from An Input Voltage Above or Below 5V

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- L1B L1A +
C1 VIN
ducing dI/dt in the ground plane. VOUT D1

C3
A SEPIC (single-ended primary inductance converter) +
1 5
schematic is shown in Figure 3. This converter topology C2

produces a regulated output voltage that spans (i.e., can 2

be higher or lower than) the output. Recommended com- 3 4 SHUTDOWN

ponent placement for a SEPIC is shown in Figure 4. VIAS TO
GROUND
PLANE
R2

GROUND R1
L1 + 1613 F04
C1 VIN
VOUT D1
Figure 4. Recommended Component Placement for SEPIC

+
C2 1 5
COMPONENT SELECTION
2

3 4 SHUTDOWN
Inductors
VIAS TO
GROUND
PLANE
Inductors used with the LT1613 should have a saturation
R2
current rating (where inductance is approximately 70% of
zero current inductance) of approximately 0.5A or greater.
R1
GROUND
1613 F02
DCR of the inductors should be 0.5Ω or less. For boost
converters, inductance should be 4.7µH for input voltage
Figure 2. Recommended Component Placement for Boost less than 3.3V and 10µH for inputs above 3.3V. When
Converter. Note Direct High Current Paths Using Wide PCB
Traces. Minimize Area at Pin 3 (FB). Use Vias to Tie Local using the device as a SEPIC, either a coupled inductor or
Ground Into System Ground Plane. Use Vias at Location Shown two separate inductors can be used. If using separate
to Avoid Introducing Switching Currents Into Ground Plane 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.

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LT1613
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OPERATIO
Table 1 lists several inductors that will work with the lower ESR will result in lower output ripple.
LT1613, although this is not an exhaustive list. There are
Ceramic capacitors can be used with the LT1613 provided
many magnetics vendors whose components are suitable
loop stability is considered. A tantalum capacitor has
for use.
some ESR and this causes an “ESR zero” in the regulator
Diodes loop. This zero is beneficial to loop stability. The internally
compensated LT1613 does not have an accessible com-
A Schottky diode is recommended for use with the LT1613. pensation node, but other circuit techniques can be em-
The Motorola MBR0520 is a very good choice. Where the ployed to counteract the loss of the ESR zero, as detailed
input to output voltage differential exceeds 20V, use the in the next section.
MBR0530 (a 30V diode). If cost is more important than
efficiency, the 1N4148 can be used, but only at low current Some capacitor types appropriate for use with the LT1613
loads. are listed in Table 2.

Capacitors OPERATION WITH CERAMIC CAPACITORS

The input bypass capacitor must be placed physically Because the LT1613 is internally compensated, loop sta-
close to the input pin. ESR is not critical and in most cases bility must be carefully considered when choosing an
an inexpensive tantalum is appropriate. output capacitor. Small, low cost tantalum capacitors
The choice of output capacitor is far more important. The have some ESR, which aids stability. However, ceramic
quality of this capacitor is the greatest determinant of the capacitors are becoming more popular, having attractive
output voltage ripple. The output capacitor must have characteristics such as near-zero ESR, small size and
enough capacitance to satisfy the load under transient reasonable cost. Simply replacing a tantalum output ca-
conditions and it must shunt the switched component of pacitor with a ceramic unit will decrease the phase margin,
current coming through the diode. Output voltage ripple in some cases to unacceptable levels. With the addition of
results when this switched current passes through the a phase lead capacitor (CPL) and isolating resistor (R3),
the LT1613 can be used successfully with ceramic output
finite output impedance of the output capacitor. The
capacitors as described in the following figures.
capacitor should have low impedance at the 1.4MHz
switching frequency of the LT1613. At this frequency, the A boost converter, stepping up 2.5V to 5V, is shown in
impedance is usually dominated by the capacitor’s equiva- Figure 5. Tantalum capacitors are used for the input and
lent series resistance (ESR). Choosing a capacitor with 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

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 LT1613
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OPERATIO
effect on loop stability, as long as minimum capacitance resulting in a severely underdamped response. By adding
requirements are met). The transient response to a load R3 and CPL as detailed in Figure 8’s schematic, phase
step of 50mA to 100mA is pictured in Figure 6. Note the margin is restored, and transient response to the same
“double trace,” due to the ESR of C2. The loop is stable and load step is pictured in Figure 9. R3 isolates the device FB
settles in less than 100µs. In Figure 7, C2 is replaced by a pin from fast edges on the VOUT node due to parasitic PC
10µF ceramic unit. Phase margin decreases drastically, trace inductance.
L1 Figure 10’s circuit details a 5V to 12V boost converter,
D1
VIN
10µH
VOUT delivering up to 130mA. The transient response to a load
2.5V 5V step of 10mA to 130mA, without CPL, is pictured in
+ C1 VIN SW R1 Figure␣ 11. Although the ringing is less than that of the
15µF 37.4k
+ previous example, the response is still underdamped and
LT1613 C2
22µF can be improved. After adding R3 and CPL, the improved
SHDN SHDN FB
GND
transient response is detailed in Figure 12.
R2
12.1k
Figure 13 shows a SEPIC design, converting a 3V to 10V
C1: AVX TAJA156M010R input to a 5V output. The transient response to a load step
C2: AVX TAJA226M006R
D1: MOTOROLA MBR0520
of 20mA to 120mA, without CPL and R3, is pictured in
L1: MURATA LQH3C100 1613 F05
Figure␣ 14. After adding these two components, the im-
Figure 5. 2.5V to 5V Boost Converter with “A” proved response is shown in Figure 15.
Case Size Tantalum Input and Output Capacitors
L1
10µH D1
VIN VOUT
2.5V 5V
CPL
+ C1 VIN SW 330pF
VOUT 15µF
R1
20mV/DIV LT1613 R3 C2
37.4k
AC COUPLED 10k 10µF
SHUTDOWN SHDN FB
GND R2
12.1k
100mA
LOAD CURRENT
50mA C1: AVX TAJA156M010R
200µs/DIV 1613 F06
C2: TAIYO YUDEN LMK325BJ106MN
D1: MBR0520
L1: MURATA LQH3C100K04 1613 F08
Figure 6. 2.5V to 5V Boost Converter Transient
Response with 22µF Tantalum Output Capacitor. Figure 8. 2.5V to 5V Boost Converter with Ceramic
Apparent Double Trace on VOUT Is Due to Switching Output Capacitor. CPL Added to Increase Phase Margin,
Frequency Ripple Current Across Capacitor ESR R3 Isolates FB Pin from Fast Edges

VOUT VOUT
20mV/DIV 20mV/DIV
AC COUPLED AC COUPLED

100mA 100mA
LOAD CURRENT LOAD CURRENT
50mA 50mA
200µs/DIV 1613 F07 200µs/DIV 1613 F09

Figure 7. 2.5V to 5V Boost Converter with Figure 9. 2.5V to 5V Boost Converter with 10µF Ceramic
10µF Ceramic Output Capacitor, No CPL Output Capacitor, 330pF CPL and 10k in Series with FB Pin

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LT1613
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OPERATIO
L1 C3
D1 L1
10µH VOUT 1µF
VIN VIN 22µH
12V
5V 3V TO
130mA
CPL 10V
+ C1 VIN SW 200pF +
L2 CPL D1
C1 VIN SW 22µH 330pF
22µF 22µF
R1
LT1613 R3 C2
107k LT1613 R3
10k 4.7µF 10k
SHUTDOWN SHDN FB VOUT
SHUTDOWN SHDN FB
GND 5V
R2 GND R1
R2 C2
12.3k 37.4k
12.1k 10µF

C1: AVX TAJB226M010

C1: AVX TAJB226M010
C2: TAIYO YUDEN EMK325BJ475MN
C2: TAIYO YUDEN LMK325BJ106MN
D1: MOTOROLA MBR0520
C3: TAIYO YUDEN LMK212BJ105MG
L1: MURATA LQH3C100 1613 F10
D1: MOTOROLA MBR0520 1613 F13

L1, L2: MURATA LQH3C220

Figure 10. 5V to 12V Boost Converter with 4.7µF Ceramic
Output Capacitor, CPL Added to Increase Phase Margin Figure 13. 5V Output SEPIC with Ceramic
Output Capacitor. CPL Adds Phase Margin

VOUT VOUT
100mV/DIV 50mV/DIV
AC COUPLED AC COUPLED

130mA 120mA
LOAD CURRENT LOAD CURRENT
10mA 20mA
200µs/DIV 1613 F11 200µs/DIV 1613 F14

Figure 11. 5V to 12V Boost Converter Figure 14. 5V Output SEPIC with 10µF
with 4.7µF Ceramic Output Capacitor Ceramic Output Capacitor. No CPL. VIN = 4V

VOUT VOUT
100mV/DIV 50mV/DIV
AC COUPLED AC COUPLED

130mA 120mA
LOAD CURRENT LOAD CURRENT
10mA 20mA
200µs/DIV 1613 F12 200µs/DIV 1613 F15

Figure 12. 5V to 12V Boost Converter with 4.7µF Figure 15. 5V Output SEPIC with 10µF Ceramic Output
Ceramic Output Capacitor and 200pF Phase-Lead Capacitor, 330pF CPL and 10k in Series with FB Pin
Capacitor CPL and 10k in Series with FB Pin

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 LT1613
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OPERATIO
START-UP/SOFT-START time required to reach final value increases to 1.7ms. In
Figure 19, CS is increased to 33nF. Input current does not
When the LT1613 SHDN pin voltage goes high, the device
exceed the steady-state current the device uses to supply
rapidly increases the switch current until internal current
power to the 50Ω load. Start-up time increases to 4.3ms.
limit is reached. Input current stays at this level until the
CS can be increased further for an even slower ramp, if
output capacitor is charged to final output voltage. Switch
desired.
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 VOUT
2V/DIV
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. IIN
200mA/DIV
Soft-start reduces the inrush current by taking more time
to reach final output voltage. A soft-start circuit consisting VS
5V/DIV
of Q1, RS1, RS2 and CS1 as shown in Figure 17 can be used 500µs/DIV 1613 F18

to limit inrush current to a lower value. Figure 18 pictures Figure 18. Soft-Start Components in Figure 17’s SEPIC
VOUT and input current with RS2 of 33kΩ and CS of 10nF. Reduces Inrush Current. CSS = 10nF, RLOAD = 50Ω
Input current is limited to a peak value of 200mA as the

VOUT VOUT
2V/DIV 2V/DIV

IIN IIN
200mA/DIV 200mA/DIV

VSHDN VS
5V/DIV 5V/DIV
200µs/DIV 1613 F16 1ms/DIV 1613 F18

Figure 16. Start-Up Waveforms of Figure 19. Increasing CS to 33nF Further

Figure 17’s SEPIC Into 50Ω Load Reduces Inrush Current. RLOAD = 50Ω

C3
L1
1µF
22µH
VIN
4V
C1 +
L2 CPL D1
22µF VIN SW 22µH 330pF
SOFT-START COMPONENTS
RS1 LT1613 R3
33k 10k
VOUT
VS SHDN FB
5V
Q1 GND R2 R1
2N3904 37.4k RLOAD
CS 12.1k
RS2 C2
10nF/ 33k
33nF 10µF

1613 F17

C1: AVX TAJB226M006 D1: MOTOROLA MBR0520

C2: TAIYO YUDEN LMK325BJ106MN L1, L2: MURATA LQH3C220
C3: TAIYO YUDEN LMK212BJ105MG
Figure 17. 5V SEPIC with Soft-Start Components

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LT1613
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TYPICAL APPLICATIO S
4-Cell to 5V SEPIC DC/DC Converter
C3
L1
1µF D1
22µH
6.5V TO 4V

VOUT
+ C1 VIN SW 5V
15µF 175mA
L2
LT1613 374k
4-CELL 22µH + C2
SHDN SHDN FB 22µF
GND
121k

L1, L2: MURATA LQH3C220

C3: AVX 1206YG105 CERAMIC 1613 • TA03

D1: MBR0520

4-Cell to 15V/30mA DC/DC Converter

L1
VIN 10µH D1 Efficiency
VOUT
3.5V TO
15V/30mA 85
8V
VIN = 6.5V
+ C1 VIN SW 80
1nF
22µF R1
LT1613 137k + C2 75 VIN = 5V
10k 1% VIN = 3.6V
EFFICIENCY (%)
4.7µF
SHDN SHDN FB 70
GND R2
12.1k 65

C1: AVX TAJB226M016 60

C2: AVX TAJA475M025
D1: MOTOROLA MBR0520 55
L1: MURATA LQH3C100 1613 TA04

50
0 10 20 30 40 50 60 70 80 90 100
LOAD CURRENT (mA)
1613 TA04a

3.3V to 8V/70mA, – 8V/5mA, 24V/5mA TFT LCD Bias Supply Uses All Ceramic Capacitors
D2
VOFF
– 8V
1µF 5mA
D3 VON
24V
0.22µF 0.22µF 1µF 5mA

0.22µF: TAIYO YUDEN EMK212BJ224MG

1µF: TAIYO YUDEN LMK212BJ105MG D4
4.7µF: TAIYO YUDEN LMK316BJ475ML
D1: MOTOROLA MBRO520 0.22µF 1µF
D2, D3, D4: BAT54S
L1: SUMIDA CDRH5D185R4
L1
5.4µH D1
VIN
3.3V AVDD
8V
VIN SW 70mA

LT1613 274k
C1 C2
4.7µF 4.7µF
SHDN FB
GND
48.7k

1613 TA05

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 LT1613
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TYPICAL APPLICATIO S
4-Cell to 5V/50mA, 12V/10mA, 15V/10mA Digital Camera Power Supply

D3
C1: TAIYO YUDEN JMK316BJ106ML 15V/10mA
2 C3
C2, C3, C4: TAIYO YUDEN EMK212BJ105MG
C5: TAIYO YUDEN JMK212BJ475MG 1µF
D1: MOTOROLA MBR0520
D2, D3: BAT54 D2
T1: COILCRAFT CCI8245A (847) 639-6400 12V/10mA
5 C4
1µF

VIN 7V TO 3.6V T1 D1
5V/50mA
6 3
C5
4.7µF
1 4
C1
10µF
C2
VIN SW 1µF 270pF

LT1613
102k
SHUTDOWN SHDN FB
GND
33.2k

1613 TA07

4-Cell to 5V/50mA, 15V/10mA, – 7.5V/10mA Digital Camera Power Supply

D2
C1: TAIYO YUDEN JMK316BJ106ML 15V/10mA
2 C3
C2, C3, C4: TAIYO YUDEN EMK212BJ105MG
C5: TAIYO YUDEN JMK212BJ475MG 1µF
D1: MOTOROLA MBR0520
D2, D3: BAT54 D1
T1: COILCRAFT CCI8244A (847) 639-6400 5V/50mA
5 C5
4.7µF

VIN 7V TO 3.6V T1
6 3
C4
1µF
D3
1 4
–7.5V/10mA
C1
10µF
C2
VIN SW 1µF 270pF

LT1613
102k
SHUTDOWN SHDN FB
GND
33.2k

1613 TA08

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. 11
LT1613
U
TYPICAL APPLICATIONS
Li-Ion to 16V/20mA Step-Up DC/DC Converter
L1 D1
VIN 2.2µH
2.7V
TO 4.5V
+ C1 VIN SW
4.7µF
LT1613 165k
1% 16V
SHDN SHDN FB
20mA
GND C2
13.7k
1µF
1%
X5R
CERAMIC
C1: AVX TAJA4R7M010
C2: TAIYO YUDEN LMK212BJ105MG
D1: BAT54S DUAL DIODE
L1: MURATA LQH3C2R2 1613 TA06

U
PACKAGE DESCRIPTION Dimensions in inches (millimeters) unless otherwise noted.

S5 Package
5-Lead Plastic SOT-23
(LTC DWG # 05-08-1633)
2.60 – 3.00
(0.102 – 0.118)
2.80 – 3.00
1.50 – 1.75 (0.110 – 0.118)
0.00 – 0.15 0.90 – 1.45
(0.059 – 0.069) (NOTE 3)
(0.00 – 0.006) (0.035 – 0.057)

0.35 – 0.55
(0.014 – 0.022)
0.09 – 0.20 0.35 – 0.50 0.90 – 1.30
0.95
(0.004 – 0.008) (0.014 – 0.020) (0.035 – 0.051)
1.90 (0.037)
(NOTE 2) FIVE PLACES (NOTE 2)
(0.074) REF
NOTE: REF S5 SOT-23 0599
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)

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 IQ, 9V to 5V at 250µA
LT1521 300mA Low Dropout Regulator with Micropower Quiescent 500mV Dropout, 300mA Output Current, 12µA IQ
Current and Shutdown
LTC1517-5 Micropower, Regulated Charge Pump 3-Cells to 5V at 20mA, SOT-23 Package, 6µA IQ
LT1610 1.7MHz Single Cell Micropower DC/DC Converter 30µA IQ, 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

sn1613 1613fs LT/TP 1299 4K • PRINTED IN USA

Linear Technology Corporation
12 1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408)432-1900 ● FAX: (408) 434-0507 ● www.linear-tech.com  LINEAR TECHNOLOGY CORPORATION 1997