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LT1613 1.4MHz, Single Cell DC/DC Converter in 5-Lead SOT-23
FEATURES
s s s s s s s s s s s
DESCRIPTIO
Uses Tiny Capacitors and Inductor Internally Compensated Fixed Frequency 1.4MHz Operation Operates with VIN 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: <1A Low VCESAT Switch: 300mV at 300mA Tiny 5-Lead SOT-23 Package
The LT(R)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 approaches using a single regulator and a custom transformer. 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.
, LTC and LT are registered trademarks of Linear Technology Corporation.
APPLICATIO S
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Digital Cameras Pagers Cordless Phones Battery Backup LCD Bias Medical Diagnostic Equipment Local 5V or 12V Supply External Modems PC Cards
TYPICAL APPLICATIO
L1 4.7H VIN 3.3V
D1 VOUT 5V 200mA 100 95 90
EFFICIENCY (%)
+
VIN C1 15F SHDN LT1613 SHDN GND
SW
R1 37.4k
+
C2 22F
85 80 75 70 65 VIN = 1.5V VIN = 2.8V VIN = 3.5V
FB R2 12.1k
L1: MURATA LQH3C4R7M24 OR SUMIDA CD43-4R7 C1: AVX TAJA156M010 C2: AVX TAJB226M006 D1: MBR0520
60
1613 TA01
55 50 0 50 100 150 200 250 300 350 400 LOAD CURRENT (mA)
1613 TA01a
Figure 1. 3.3V to 5V 200mA DC/DC Converter
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Efficiency Curve
VIN = 4.2V
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1
LT1613
ABSOLUTE MAXIMUM RATINGS
(Note 1)
PACKAGE/ORDER INFORMATION
ORDER PART NUMBER
TOP VIEW SW 1 GND 2 FB 3 4 SHDN 5 VIN
VIN Voltage .............................................................. 10V SW Voltage ................................................- 0.4V to 36V FB Voltage ..................................................... VIN + 0.3V Current into FB Pin ............................................... 1mA SHDN Voltage .......................................................... 10V Maximum Junction Temperature .......................... 125C Operating Temperature Range Commercial ............................................. 0C to 70C Extended Commercial (Note 2) ........... - 40C to 85C Storage Temperature Range ................. - 65C to 150C Lead Temperature (Soldering, 10 sec).................. 300C
LT1613CS5
S5 PACKAGE 5-LEAD PLASTIC SOT-23
S5 PART MARKING LTED
Consult factory for Industrial and Military grade parts.
The q denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. Commercial grade 0C to 70C, VIN = 1.5V, VSHDN = VIN unless otherwise noted. (Note 2)
PARAMETER Minimum Operating Voltage Maximum Operating Voltage Feedback Voltage FB Pin Bias Current Quiescent Current Quiescent Current in Shutdown Reference Line Regulation Switching Frequency Maximum Duty Cycle Switch Current Limit Switch VCESAT Switch Leakage Current SHDN Input Voltage High SHDN Input Voltage Low SHDN Pin Bias Current VSHDN = 3V VSHDN = 0V 25 0.01 (Note 3) ISW = 300mA VSW = 5V 1 0.3 50 0.1 VSHDN = 1.5V VSHDN = 0V, VIN = 2V VSHDN = 0V, VIN = 5V 1.5V VIN 10V
q q q q
ELECTRICAL CHARACTERISTICS
CONDITIONS
MIN
TYP 0.9
MAX 1.1 10 1.255 80 4.5 0.5 1.0 0.2 1.8
UNITS V V V nA mA A A %/V MHz % mA
1.205
1.23 27 3 0.01 0.01 0.02
1.0 82 550
1.4 86 800 300 0.01
350 1
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 0C to 70C. Specifications over the - 40C to 85C 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.
2
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W
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WW
W
mV A V V A A
LT1613 TYPICAL PERFOR A CE CHARACTERISTICS
Switch VCESAT vs Switch Current
700 600 500 TA = 25C 2.00 1.75 VIN = 5V SHDN PIN BIAS CURRENT (A) 40
SWITCHING FREQUENCY (MHz)
VCESAT (mV)
400 300 200 100 0 0 100 200 300 400 500 SWITCH CURRENT (mA) 600 700
Current Limit vs Duty Cycle
1000 900
CURRENT LIMIT (mA)
800 70C 700 600 500 400 300 200 10 20 30 40 50 60 DUTY CYCLE (%) 70 80 -40C 25C
FEEDBACK PIN VOLTAGE (V)
UW
Oscillator Frequency vs Temperature
50
SHDN Pin Current vs VSHDN
TA = 25C
1.50 1.25 1.00 0.75 0.50 0.25 0 -50 VIN = 1.5V
30
20
10
0 -25 0 25 50 TEMPERATURE (C) 75 100
1613 G02
0
1
2 3 4 SHDN PIN VOLTAGE (V)
5
1613 G03
1613 G01
Feedback Pin Voltage
1.25
1.24 VOLTAGE 1.23
1.22
1.21
1.20 -50
-25
0 25 50 TEMPERATURE (C)
75
100
1613 G05
1613 G04
Switching Waveforms, Circuit of Figure 1
VOUT 100mV/DIV AC COUPLED VSW 5V/DIV
ISW 200mA/DIV ILOAD = 150mA 200ns/DIV
1613 G06
3
LT1613
PIN FUNCTIONS
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 VOUT according to VOUT = 1.23V(1 + R1/R2). SHDN (Pin 4): Shutdown Pin. Tie to 1V or more to enable device. Ground to shut down. VIN (Pin 5): Input Supply Pin. Must be locally bypassed.
BLOCK DIAGRAM
VIN 5 R5 40k VOUT R1 (EXTERNAL) FB Q1 3
-
Q2 x10 R3 30k R4 140k
FB
CC
R2 (EXTERNAL)
1.4MHz OSCILLATOR SHDN 4 SHUTDOWN
OPERATIO
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 VIN is 1V. When there is no load, FB rises slightly above 1.23V, causing VC (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 VC 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 subharmonic oscillations at duty factors greater than
50%) exceeds the VC 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 RC and CC. Transient response can be optimized by the addition of a phase lead capacitor CPL 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. If the FB pin voltage is increased significantly above 1.23V, the LT1613 will enter a low power state where quiescent current falls to approximately 100A.
4
+
RC
RAMP GENERATOR
-
W
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VIN R6 40k
+
A1 gm
1 SW COMPARATOR FF S DRIVER Q Q3
A2
R
+
0.15
-
2 GND
1613 * BD
LT1613
OPERATIO
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 CIN to VIN 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 introducing 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 component placement for a SEPIC is shown in Figure 4.
VOUT
D1
+
C2
VIAS TO GROUND PLANE R2
GROUND
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
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VIN 4V TO 7V L1A 22H C3 1F
+
C1 15F
VIN LT1613
SW R1 100k FB GND R2 32.4k
L1B 22H
D1
SHDN
SHDN
+
VOUT 5V/150mA C2 15F
C1, C2: AVX TAJA156M016 C3: TAIYO YUDEN JMK325BJ226MM D1: MOTOROLA MBR0520 L1, L2: MURATA LQH3C220
1613 F03
Figure 3. Single-Ended Primary Inductance Converter (SEPIC) Generates 5V from An Input Voltage Above or Below 5V
L1B VOUT D1 C3
L1A
+
C1 VIN
+
C2
1
5
2 SHUTDOWN
3 VIAS TO GROUND PLANE R2
4
L1
+
C1 VIN
GROUND
R1
1613 F04
Figure 4. Recommended Component Placement for SEPIC
1 5
COMPONENT SELECTION
SHUTDOWN
2
3
4
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 0.5 or less. For boost converters, inductance should be 4.7H for input voltage less than 3.3V and 10H 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, 22H units are recommended for input voltage above 3.3V. Coupled inductors have a beneficial mutual inductance, so a 10H coupled inductor results in the same ripple current as two 20H uncoupled units.
R1
1613 F02
5
LT1613
OPERATIO
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 equivalent series resistance (ESR). Choosing a capacitor with
Table 1. Inductor Vendors
VENDOR Sumida Murata PHONE (847) 956-0666 (404) 436-1300 URL www.sumida.com www.murata.com
Coiltronics
Table 2. Capacitor Vendors
VENDOR Taiyo Yuden AVX Murata PHONE (408) 573-4150 (803) 448-9411 (404) 436-1300 URL www.t-yuden.com www.avxcorp.com www.murata.com PART Ceramic Caps Ceramic Caps Tantalum Caps Ceramic Caps COMMENT X5R Dielectric
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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 compensation node, but other circuit techniques can be employed 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 stability 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 capacitor with a ceramic unit will decrease the phase margin, in some cases to unacceptable levels. With the addition of a phase lead capacitor (CPL) 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
PART CLS62-22022 CD43-220 LQH3C-220 LQH3C-100 LQH3C-4R7 CTX20-1 COMMENT 22H Coupled 22H 22H, 2mm Height 10H 4.7H 20H Coupled, Low DCR (407) 241-7876 www.coiltronics.com
LT1613
OPERATIO
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 100s. In Figure 7, C2 is replaced by a 10F ceramic unit. Phase margin decreases drastically,
VIN 2.5V L1 10H D1 VOUT 5V SW LT1613 SHDN SHDN GND FB R2 12.1k R1 37.4k
+
C1 15F
VIN
C1: AVX TAJA156M010R C2: AVX TAJA226M006R D1: MOTOROLA MBR0520 L1: MURATA LQH3C100
Figure 5. 2.5V to 5V Boost Converter with "A" Case Size Tantalum Input and Output Capacitors
VOUT 20mV/DIV AC COUPLED
LOAD CURRENT
100mA 50mA 200s/DIV
1613 F06
Figure 6. 2.5V to 5V Boost Converter Transient Response with 22F Tantalum Output Capacitor. Apparent Double Trace on VOUT Is Due to Switching Frequency Ripple Current Across Capacitor ESR
VOUT 20mV/DIV AC COUPLED
LOAD CURRENT
100mA 50mA 200s/DIV
1613 F07
Figure 7. 2.5V to 5V Boost Converter with 10F Ceramic Output Capacitor, No CPL
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resulting in a severely underdamped response. By adding R3 and CPL 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 VOUT 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 CPL, 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 CPL, 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 CPL and R3, is pictured in Figure 14. After adding these two components, the improved response is shown in Figure 15.
VIN 2.5V L1 10H D1 VOUT 5V SW LT1613 SHUTDOWN SHDN GND FB R2 12.1k R3 10k CPL 330pF R1 37.4k C2 10F
+
C2 22F
1613 F05
+
C1 15F
VIN
C1: AVX TAJA156M010R C2: TAIYO YUDEN LMK325BJ106MN D1: MBR0520 L1: MURATA LQH3C100K04
1613 F08
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
VOUT 20mV/DIV AC COUPLED
LOAD CURRENT
100mA 50mA 200s/DIV
1613 F09
Figure 9. 2.5V to 5V Boost Converter with 10F Ceramic Output Capacitor, 330pF CPL and 10k in Series with FB Pin
7
LT1613
OPERATIO
VIN 5V
+
C1 22F
SHUTDOWN
C1: AVX TAJB226M010 C2: TAIYO YUDEN EMK325BJ475MN D1: MOTOROLA MBR0520 L1: MURATA LQH3C100
Figure 10. 5V to 12V Boost Converter with 4.7F Ceramic Output Capacitor, CPL Added to Increase Phase Margin
VOUT 100mV/DIV AC COUPLED
LOAD CURRENT
130mA 10mA 200s/DIV
1613 F11
Figure 11. 5V to 12V Boost Converter with 4.7F Ceramic Output Capacitor
VOUT 100mV/DIV AC COUPLED
LOAD CURRENT
130mA 10mA 200s/DIV
1613 F12
Figure 12. 5V to 12V Boost Converter with 4.7F Ceramic Output Capacitor and 200pF Phase-Lead Capacitor CPL and 10k in Series with FB Pin
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L1 10H D1 VOUT 12V 130mA CPL 200pF R3 10k FB GND R2 12.3k R1 107k C2 4.7F SHUTDOWN VIN 3V TO 10V L1 22H C3 1F VIN LT1613 SHDN SW
+
C1 22F
VIN LT1613 SHDN GND
SW
L2 22H R3 10k
CPL 330pF
D1
FB R2 12.1k R1 37.4k
VOUT 5V C2 10F
1613 F10
C1: AVX TAJB226M010 C2: TAIYO YUDEN LMK325BJ106MN C3: TAIYO YUDEN LMK212BJ105MG D1: MOTOROLA MBR0520 L1, L2: MURATA LQH3C220
1613 F13
Figure 13. 5V Output SEPIC with Ceramic Output Capacitor. CPL Adds Phase Margin
VOUT 50mV/DIV AC COUPLED
LOAD CURRENT
120mA 20mA 200s/DIV
1613 F14
Figure 14. 5V Output SEPIC with 10F Ceramic Output Capacitor. No CPL. VIN = 4V
VOUT 50mV/DIV AC COUPLED
LOAD CURRENT
120mA 20mA 200s/DIV
1613 F15
Figure 15. 5V Output SEPIC with 10F Ceramic Output Capacitor, 330pF CPL and 10k in Series with FB Pin
LT1613
OPERATIO
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 50 load without any soft-start. The output voltage reaches final value in approximately 200s, 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, RS1, RS2 and CS1 as shown in Figure 17 can be used to limit inrush current to a lower value. Figure 18 pictures VOUT and input current with RS2 of 33k and CS of 10nF. Input current is limited to a peak value of 200mA as the
VOUT 2V/DIV
IIN 200mA/DIV VSHDN 5V/DIV 200s/DIV
1613 F16
Figure 16. Start-Up Waveforms of Figure 17's SEPIC Into 50 Load
L1 22H C1 22F SOFT-START COMPONENTS RS1 33k VS CS 10nF/ 33nF RS2 33k Q1 2N3904 C3 1F
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time required to reach final value increases to 1.7ms. In Figure 19, CS is increased to 33nF. Input current does not exceed the steady-state current the device uses to supply power to the 50 load. Start-up time increases to 4.3ms. CS can be increased further for an even slower ramp, if desired.
VOUT 2V/DIV IIN 200mA/DIV VS 5V/DIV 500s/DIV
1613 F18
Figure 18. Soft-Start Components in Figure 17's SEPIC Reduces Inrush Current. CSS = 10nF, RLOAD = 50
VOUT 2V/DIV
IIN 200mA/DIV VS 5V/DIV 1ms/DIV
1613 F18
Figure 19. Increasing CS to 33nF Further Reduces Inrush Current. RLOAD = 50
VIN 4V
+
VIN LT1613 SHDN GND FB SW
L2 22H R3 10k R2 12.1k
CPL 330pF
D1
R1 37.4k C2 10F
VOUT 5V RLOAD
1613 F17
C1: AVX TAJB226M006 C2: TAIYO YUDEN LMK325BJ106MN C3: TAIYO YUDEN LMK212BJ105MG
D1: MOTOROLA MBR0520 L1, L2: MURATA LQH3C220
Figure 17. 5V SEPIC with Soft-Start Components
9
LT1613
TYPICAL APPLICATIO S
4-Cell to 5V SEPIC DC/DC Converter
6.5V TO 4V L1 22H C3 1F D1
VIN 3.5V TO 8V
L1 10H
+
C1 22F
VIN LT1613
SHDN
SHDN GND
FB R2 12.1k
EFFICIENCY (%)
C1: AVX TAJB226M016 C2: AVX TAJA475M025 D1: MOTOROLA MBR0520 L1: MURATA LQH3C100
3.3V to 8V/70mA, - 8V/5mA, 24V/5mA TFT LCD Bias Supply Uses All Ceramic Capacitors
D2 VOFF - 8V 5mA D3 0.22F 0.22F: TAIYO YUDEN EMK212BJ224MG 1F: TAIYO YUDEN LMK212BJ105MG 4.7F: TAIYO YUDEN LMK316BJ475ML D1: MOTOROLA MBRO520 D2, D3, D4: BAT54S L1: SUMIDA CDRH5D185R4 L1 5.4H VIN 3.3V VIN C1 4.7F LT1613 SHDN GND FB 48.7k 0.22F 1F VON 24V 5mA
10
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+
4-CELL
C1 15F
VIN LT1613
SW 374k FB GND 121k L2 22H
VOUT 5V 175mA
+
SHDN
SHDN
C2 22F
L1, L2: MURATA LQH3C220 C3: AVX 1206YG105 CERAMIC D1: MBR0520
1613 * TA03
4-Cell to 15V/30mA DC/DC Converter
D1 VOUT 15V/30mA SW 1nF 10k
85 80 VIN = 6.5V
Efficiency
R1 137k 1%
+
C2 4.7F
75 70 65 60 55
VIN = 3.6V
VIN = 5V
1613 TA04
50 0 10 20 30 40 50 60 70 80 90 100 LOAD CURRENT (mA)
1613 TA04a
1F
D4 0.22F 1F
D1 AVDD 8V 70mA 274k C2 4.7F
SW
1613 TA05
LT1613
TYPICAL APPLICATIO S
4-Cell to 5V/50mA, 12V/10mA, 15V/10mA Digital Camera Power Supply
D3 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 2 15V/10mA C3 1F D2 5 12V/10mA C4 1F D1 3 C5 4.7F 1 C1 10F VIN LT1613 102k SHUTDOWN SHDN GND FB 33.2k SW C2 1F 4 5V/50mA
VIN 7V TO 3.6V
4-Cell to 5V/50mA, 15V/10mA, - 7.5V/10mA Digital Camera Power Supply
D2 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 2 15V/10mA C3 1F D1 5 5V/50mA C5 4.7F
SHUTDOWN
Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
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T1 6
270pF
1613 TA07
VIN 7V TO 3.6V
T1 6 3 C4 1F -7.5V/10mA
1 C1 10F VIN LT1613 SW
4
D3
C2 1F
270pF
102k SHDN GND FB 33.2k
1613 TA08
11
LT1613
TYPICAL APPLICATIONS
Li-Ion to 16V/20mA Step-Up DC/DC Converter
VIN 2.7V TO 4.5V L1 2.2H D1
PACKAGE DESCRIPTION
2.60 - 3.00 (0.102 - 0.118) 1.50 - 1.75 (0.059 - 0.069) 0.00 - 0.15 (0.00 - 0.006) 0.90 - 1.45 (0.035 - 0.057) 2.80 - 3.00 (0.110 - 0.118) (NOTE 3)
0.35 - 0.55 (0.014 - 0.022)
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)
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PART NUMBER LT1307 LT1317 LTC1474 LT1521 LTC1517-5 LT1610 LT1611 LT1615/LT1615-1 DESCRIPTION Single Cell Micropower DC/DC 2-Cell Micropower DC/DC Low Quiescent Current, High Efficiency Step-Down Converter 300mA Low Dropout Regulator with Micropower Quiescent Current and Shutdown Micropower, Regulated Charge Pump 1.7MHz Single Cell Micropower DC/DC Converter Inverting 1.4MHz Switching Regulator Micropower DC/DC Converter in 5-Lead SOT-23 COMMENTS 3.3V/75mA From 1V; 600kHz Fixed Frequency 3.3V/200mA From Two Cells; 600kHz Fixed Frequency 94% Efficiency, 10A IQ, 9V to 5V at 250A 500mV Dropout, 300mA Output Current, 12A IQ 3-Cells to 5V at 20mA, SOT-23 Package, 6A IQ 30A IQ, MSOP Package, Internal Compensation 5V to -5V at 150mA, Low Output Noise 20V at 12mA from 2.5V Input, Tiny SOT-23 Package
1613f LT/TP 1299 4K * PRINTED IN USA
12
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408)432-1900 q FAX: (408) 434-0507 q www.linear-tech.com
U
U
+
C1 4.7F
VIN LT1613
SW 165k 1% FB GND 13.7k 1%
SHDN
SHDN
16V 20mA C2 1F X5R CERAMIC
C1: AVX TAJA4R7M010 C2: TAIYO YUDEN LMK212BJ105MG D1: BAT54S DUAL DIODE L1: MURATA LQH3C2R2
1613 TA06
Dimensions in inches (millimeters) unless otherwise noted. S5 Package 5-Lead Plastic SOT-23
(LTC DWG # 05-08-1633)
0.09 - 0.20 (0.004 - 0.008) (NOTE 2)
0.35 - 0.50 0.90 - 1.30 (0.014 - 0.020) (0.035 - 0.051) FIVE PLACES (NOTE 2)
1.90 (0.074) REF
0.95 (0.037) REF
S5 SOT-23 0599
(c) LINEAR TECHNOLOGY CORPORATION 1997

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