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LT1610 1.7MHz, Single Cell Micropower DC/DC Converter
FEATURES
s s s s s s s s s s s
DESCRIPTIO
Uses Tiny Capacitors and Inductor Internally Compensated Low Quiescent Current: 30A Operates with VIN as Low as 1V 3V at 30mA from a Single Cell 5V at 200mA from 3.3V High Output Voltage Capability: Up to 28V Low Shutdown Current: < 1A Automatic Burst ModeTM Switching at Light Load Low VCESAT Switch: 300mV at 300mA 8-Lead MSOP and SO Packages
The LT(R)1610 is a micropower fixed frequency DC/DC converter that operates from an input voltage as low as 1V. Intended for small, low power applications, it switches at 1.7MHz, allowing the use of tiny capacitors and inductors. The device can generate 3V at 30mA from a single cell (1V) supply. An internal compensation network can be connected to the LT1610's VC pin, eliminating two external components. No-load quiescent current of the LT1610 is 30A, and the internal NPN power switch handles a 300mA current with a voltage drop of 300mV. The LT1610 is available in 8-lead MSOP and SO packages.
APPLICATIO S
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Pagers Cordless Phones Battery Backup LCD Bias Portable Electronic Equipment
, LTC and LT are registered trademarks of Linear Technology Corporation. Burst Mode is a trademark of Linear Technology Corporation.
TYPICAL APPLICATIO
L1 4.7H
D1
VOUT 3V 30mA R1 1M
85 VOUT = 3V 80 VIN = 1.25V 75 VIN = 1.5V
6 VIN 3
5 SW FB LT1610 2
+
1 CELL
C1 22F
8
R2 681k GND 7
+
C2 22F
EFFICIENCY (%)
SHDN
70 65 60 55
COMP VC 1
PGND 4
C1, C2: AVX TAJA226M006R D1: MOTOROLA MBR0520 L1: MURATA LQH1C4R7
1610 F01
50 0.1 1 10 LOAD CURRENT (mA) 100
1610 TA01
Figure 1. 1-Cell to 3V Step-Up Converter
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Efficiency
VIN = 1V
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LT1610
ABSOLUTE MAXIMUM RATINGS
(Note 1)
VIN Voltage ................................................................ 8V SW Voltage ............................................... - 0.4V to 30V FB Voltage ..................................................... VIN + 0.3V VC Voltage ................................................................ 2V COMP Voltage .......................................................... 2V Current into FB Pin .............................................. 1mA SHDN Voltage ............................................................ 8V
PACKAGE/ORDER INFORMATION
TOP VIEW VC FB SHDN PGND 1 2 3 4 8 7 6 5 COMP GND VIN SW
ORDER PART NUMBER LT1610CMS8 MS8 PART MARKING LTDT
VC 1 FB 2 SHDN 3 PGND 4
MS8 PACKAGE 8-LEAD PLASTIC MSOP TJMAX = 125C, JA = 160C/W
Consult factory for Military grade parts.
The q denotes specifications which apply over the specified 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 Quiescent Current Quiescent Current in Shutdown FB Pin Bias Current Reference Line Regulation 1V VIN 2V (25C, 0C) 1V VIN 2V (70C) 2V VIN 8V (25C, 0C) 2V VIN 8V (70C) I = 2A
q q q
ELECTRICAL CHARACTERISTICS
CONDITIONS
VSHDN = 1.5V, Not Switching VSHDN = 0V, VIN = 2V VSHDN = 0V, VIN = 5V
q
Error Amp Transconductance Error Amp Voltage Gain Switching Frequency Maximum Duty Cycle
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Maximum Junction Temperature ......................... 125C Operating Temperature Range (Note 1) Commercial ............................................. 0C to 70C Extended Commercial (Note 2) .......... - 40C to 85C Industrial ........................................... - 40C to 85C Storage Temperature Range ................. - 65C to 150C Lead Temperature (Soldering, 10 sec).................. 300C
TOP VIEW 8 7 6 5 COMP GND VIN SW
ORDER PART NUMBER LT1610CS8 LT1610IS8 S8 PART MARKING 1610 1610I
S8 PACKAGE 8-LEAD PLASTIC SO TJMAX = 125C, JA = 120C/W
MIN
TYP 0.9
MAX 1 8 1.26 60 0.5 1.0 80 1 2 0.15 0.2
UNITS V V V A A A nA %/V %/V %/V %/V mhos V/V
1.20
1.23 30 0.01 0.01 27 0.6 0.03 25 100
1.4 77 75
1.7 80
2 95 95
MHz % %
LT1610
The q denotes specifications which apply over the specified temperature range, otherwise specifications are at TA = 25C. Commercial grade 0C to 70C, VIN = 1.5V, VSHDN = VIN, unless otherwise noted. (Note 2)
PARAMETER Switch Current Limit Switch VCESAT Switch Leakage Current SHDN Input Voltage High SHDN Input Voltage Low SHDN Pin Bias Current VSHDN = 3V VSHDN = 0V 10 0.01 CONDITIONS (Note 3) ISW = 300mA
q
ELECTRICAL CHARACTERISTICS
MIN 450
TYP 600 300 0.01
MAX 900 350 400 1 0.3 0.1
UNITS mA mV mV A V V A A
VSW = 5V 1
The q denotes specifications which apply over the specified temperature range, otherwise specifications are at TA = 25C. Industrial grade - 40C to 85C, VIN = 1.5V, VSHDN = VIN, unless otherwise noted.
PARAMETER Minimum Operating Voltage Maximum Operating Voltage Feedback Voltage Quiescent Current Quiescent Current in Shutdown FB Pin Bias Current Reference Line Regulation Error Amp Transconductance Error Amp Voltage Gain 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 10 0.01 ISW = 300mA
q q
CONDITIONS TA = 85C TA = - 40C
MIN
TYP 0.9
MAX 1 1.25 8 1.26 60 0.5 1.0 80 0.15 0.2
UNITS V V V V A A A nA %/V %/V mhos V/V
1.20
1.23 30 0.01 0.01
VSHDN = 0V, VIN = 2V VSHDN = 0V, VIN = 5V
q
27 0.03 25 100
2V VIN 8V (- 40C) 2V VIN 8V (85C) I = 2A (Note 4) (Note 4)
q q
1.4 77 75 450
1.7 80 600 300 0.01
2 95 95 900 350 400 1 0.3 0.1
MHz % % mA mV mV A V V A A
VSW = 5V 1
Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: The LT1610C is guaranteed to meet specified performance from 0C to 70C and is designed, characterized and expected to meet these extended temperature limits, but is not tested at - 40C and 85C. The LT1610I is guaranteed to meet the extended temperature limits.
Note 3: Current limit guaranteed by design and/or correlation to static test. Current limit is affected by duty cycle due to ramp generator. See Block Diagram. Note 4: Not 100% tested at 85C.
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LT1610 TYPICAL PERFOR A CE CHARACTERISTICS
VCESAT vs Current
600 800 700 600 500 400 300 200 -50 CURRENT LIMIT (mA)
500 TA = 85C VCESAT (mV) 400 TA = 25C 300 TA = - 40C 200
SWITCH CURRENT LIMIT (mA)
100
0
100
500 200 300 400 SWITCH CURRENT (mA)
Oscillator Frequency vs Input Voltage
2.50 2.25
SWITCHING FREQUENCY (MHz)
TA = 25C
QUIESCENT CURRENT (A)
2.00
FEEDBACK VOLTAGE (V)
1.75 1.50 1.25 1.00 0.75 0.50 0.25 0 0 1 2 6 4 3 5 INPUT VOLTAGE (V) 7 8
SHDN Pin Current vs SHDN Pin Voltage
50 VOUT 50mV/DIV AC COUPLED IL1 100mA/DIV ILOAD 31mA 1mA
40 SHDN CURRENT (A)
30
20
10
0 0 1 2 4 3 5 6 SHDN VOLTAGE (V) 7 8
4
UW
Current Limit (DC = 30%) vs Temperature
800 700 600 500 400 300 200 100 0
-25 0 25 50 TEMPERATURE (C) 75 100
1610 G02
Current Limit vs Duty Cycle
TA = 25C
600
0
10 20 30 40 50 60 70 DUTY CYCLE (%)
80 90 100
1610 G03
1610 G01
Feedback Voltage
1.240 1.235 1.230 1.225 1.220 1.215 1.210 -50
40 35 30 25 20 15 10 5
Quiescent Current vs Temperature
-25
0 25 50 TEMPERATURE (C)
75
100
1610 G05
0 - 50
- 25
0 50 25 TEMPERATURE (C)
75
100
1610 G06
1610 G04
Transient Response, Circuit of Figure 1
VOUT 20mV/DIV AC COUPLED SWITCH VOLTAGE 2V/DIV SWITCH CURRENT 50mA/DIV VIN = 1.25V VOUT = 3V 500s/DIV
1610 TA08
Burst Mode Operation, Circuit of Figure 1
VIN = 1.25V VOUT = 3V ILOAD = 3mA
20s/DIV
1610 TA08
1610 G07
LT1610
PIN FUNCTIONS
VC (Pin 1): Error Amplifier Output. Frequency compensation network must be connected to this pin, either internal (COMP pin) or external series RC to ground. 220k/ 220pF typical value. FB (Pin 2): 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 3): Shutdown. Ground this pin to turn off device. Tie to 1V or more to enable. PGND (Pin 4): Power Ground. Tie directly to local ground plane. SW (Pin 5): Switch Pin. Connect inductor/diode here. Minimize trace area at this pin to keep EMI down. VIN (Pin 6): Input Supply Pin. Must be locally bypassed. GND (Pin 7): Signal Ground. Carries all device ground current except switch current. Tie to local ground plane. COMP (Pin 8): Internal Compensation Network. Tie to VC pin, or let float if external compensation is used. Output capacitor must be tantalum if COMP pin is used for compensation.
BLOCK DIAGRA
VIN 6
VOUT R1 (EXTERNAL) FB FB 2 Q1
R2 (EXTERNAL)
RAMP GENERATOR
1.7MHz OSCILLATOR
Figure 2. LT1610 Block Diagram
+
-
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VIN R5 40k R6 40k
+
A1 gm 1 VC 8 COMP RC CC SHUTDOWN 3 SHDN 7 GND
-
Q2 x 10 R3 30k R4 140k
+
ENABLE BIAS
-
5 SW COMPARATOR FF A2 R S Q DRIVER Q3
+
A=3 0.15
-
4 PGND
1610 F02
5
LT1610
APPLICATIONS INFORMATION
OPERATION The LT1610 combines a current mode, fixed frequency PWM architecture with Burst Mode micropower operation to maintain high efficiency at light loads. Operation can be best understood by referring to the block diagram in Figure 2. Q1 and Q2 form a bandgap reference core whose loop is closed around the output of the converter. When VIN is 1V, the feedback voltage of 1.23V, along with an 70mV drop across R5 and R6, forward biases Q1 and Q2's base collector junctions to 300mV. Because this is not enough to saturate either transistor, FB can be at a higher voltage than VIN. When there is no load, FB rises slightly above 1.23V, causing VC (the error amplifier's output) to decrease. When VC reaches the bias voltage on hysteretic comparator A1, A1's output goes low, turning off all circuitry except the input stage, error amplifier and lowbattery detector. Total current consumption in this state is 30A. As output loading causes the FB voltage to decrease, A1's output goes high, enabling the rest of the IC. Switch current is limited to approximately 100mA initially after A1's output goes high. If the load is light, the output voltage (and FB voltage) will increase until A1's output goes low, turning off the rest of the LT1610. Low frequency ripple voltage appears at the output. The ripple frequency is dependent on load current and output capacitance. This Burst Mode operation keeps the output regulated and reduces average current into the IC, resulting in high efficiency even at load currents of 1mA or less.
GROUND PLANE R1 R2 SHUTDOWN 1 2 3 4 MULTIPLE VIAs GND C2 VOUT LT1610 8 7 6 5 C1
Figure 3. Recommended Component Placement for Boost Converter. Note Direct High Current Paths Using Wide PC Traces. Minimize Trace Area at Pin 1 (VC) and Pin 2 (FB). Use Multiple Vias to Tie Pin 4 Copper to Ground Plane. Use Vias at One Location Only to Avoid Introducing Switching Currents into the Ground Plane
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If the output load increases sufficiently, A1's output remains high, resulting in continuous operation. When the LT1610 is running continuously, peak switch current is controlled by VC to regulate the output voltage. The switch is turned on at the beginning of each switch cycle. 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. Output voltage increases as switch current is increased. The output, attenuated by a resistor divider, appears at the FB pin, closing the overall loop. Frequency compensation is provided by either an external series RC network connected between the VC pin and ground or the internal RC network on the COMP pin (Pin 8). The typical values for the internal RC are 50k and 50pF. LAYOUT Although the LT1610 is a relatively low current device, its high switching speed mandates careful attention to layout for optimum performance. For boost converters, follow the component placement indicated in Figure 3 for the best results. C2's negative terminal should be placed close to Pin 4 of the LT1610. Doing this reduces switching currents in the ground copper which keeps high frequency "spike" noise to a minimum. Tie the local ground into the system ground plane at one point only, using a few vias, to avoid introducing dI/dt induced noise into the ground plane.
VIN
+
L1
+
D1
1610 F03
LT1610
APPLICATIONS INFORMATION
A SEPIC (Single-Ended Primary Inductance Converter) schematic is shown in Figure 4. This converter topology produces a regulated output over an input voltage range that spans (i.e., can be higher or lower than) the output. Recommended component placement for a SEPIC is shown in Figure 5.
C3 1F CERAMIC
INPUT Li-ION 3V to 4.2V 6 VIN
+
C1 22F 6.3V
1
8
C1, C2: AVX TAJA226M006 C3: AVX 1206YC105 (X7R) SHUTDOWN D1: MOTOROLA MBR0520 L1, L2: MURATA LQH3C220 (UNCOUPLED) OR SUMIDA CLS62-220 (COUPLED)
Figure 4. Li-Ion to 3.3V SEPIC DC/DC Converter
GROUND PLANE R1 R2 SHUTDOWN 1 2 3 4 MULTIPLE VIAs GND LT1610 8 7 6 5 C1
C2
+
Figure 5. Recommended Component Placement for SEPIC
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L1 22H
*
5 SW FB 2 604k SHDN PGND 4 3
D1
VOUT 3.3V 120mA
1M
*
L2 22H
VC LT1610 COMP GND 7
+
C2 22F 6.3V
1610 F04
VIN
+
L1 L2
C3
D1
VOUT
1610 F05
7
LT1610
APPLICATIONS INFORMATION
COMPONENT SELECTION Inductors Inductors used with the LT1610 should have a saturation current rating (-30% of zero current inductance) of approximately 0.5A or greater. DCR should be 0.5 or less. The value of the inductor should be matched to the power requirements and operating voltages of the application. In most cases a value of 4.7H or 10H is suitable. The Murata LQH3C inductors specified throughout the data sheet are small and inexpensive, and are a good fit for the LT1610. Alternatives are the CD43 series from Sumida and the DO1608 series from Coilcraft. These inductors are slightly larger but will result in slightly higher circuit efficiency. Chip inductors, although tempting to use because of their small size and low cost, generally do not have enough energy storage capacity or low enough DCR to be used successfully with the LT1610. Diodes The Motorola MBR0520 is a 0.5 amp, 20V Schottky diode. This is a good choice for nearly any LT1610 application, unless the output voltage or the circuit topology require a diode rated for higher reverse voltages. Motorola also offers the MBR0530 (30V) and MBR0540 (40V) versions. Most one-half amp and one amp Schottky diodes are suitable; these are available from many manufacturers. If you use a silicon diode, it must be an ultrafast recovery type. Efficiency will be lower due to the silicon diode's higher forward voltage drop. Capacitors The input capacitor must be placed physically close to the LT1610. ESR is not critical for the input. In most cases inexpensive tantalum can be used. 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 performs two major functions. It must have enough capacitance to satisfy the load under transient conditions and it must shunt the AC component of the current coming through the diode from the inductor. The ripple on the output results when this AC current passes through the finite impedance of the output capacitor. The capacitor should have low impedance at the 1.7MHz switching frequency of the LT1610. At this frequency, the impedance is usually dominated by the capacitor's equivalent series resistance (ESR). Choosing a capacitor with lower ESR will result in lower output ripple. Perhaps the best way to decrease ripple is to add a 1F ceramic capacitor in parallel with the bulk output capacitor. Ceramic capacitors have very low ESR and 1F is enough capacitance to result in low impedance at the switching frequency. The low impedance can have a dramatic effect on output ripple voltage. To illustrate, examine Figure 6's circuit, a 4-cell to 5V/100mA SEPIC DC/DC converter. This design uses inexpensive aluminum electrolytic capacitors at input and output to keep cost down. Figure 7 details converter operation at a 100mA load, without ceramic capacitor C5. Note the 400mV spikes on VOUT. After C5 is installed, output ripple decreases by a factor of 8 to about 50mVP-P. The addition of C5 also improves efficiency by 1 to 2 percent. Low ESR and the required bulk output capacitance can be obtained using a single larger output capacitor. Larger tantalum capacitors, newer capacitor technologies (for example the POSCAP from Sanyo and SPCAP from Panasonic) or large value ceramic capacitors will reduce the output ripple. Note, however, that the stability of the circuit depends on both the value of the output capacitor and its ESR. When using low value capacitors or capacitors with very low ESR, circuit stability should be evaluated carefully, as described below. Loop Compensation The LT1610 is a current mode PWM switching regulator that achieves regulation with a linear control loop. The LT1610 provides the designer with two methods of compensating this loop. First, you can use an internal compensation network by tying the COMP pin to the VC pin. This results in a very small solution and reduces the circuit's total part count. The second option is to tie a resistor RC and a capacitor CC in series from the VC pin to ground. This allows optimization of the transient response for a wide variety of operating conditions and power components.
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LT1610
APPLICATIONS INFORMATION
L1 22H
+
4 CELLS
C1 22F 6.3V
C4 1F CERAMIC
C1, C2: ALUMINUM ELECTROLYTIC C3 TO C5: CERAMIC X7R OR X5R D1: MBR0520 L1, L2: MURATA LQH3C220 OR SUMIDA CLS62-220
Figure 6. 4-Cell Alkaline to 5V/120mA SEPIC DC/DC Converter
VOUT 200mV/DIV IDIODE 500mA/DIV SWITCH VOLTAGE 10V/DIV 100ns/DIV
1610 F07
Figure 7. Switching Waveforms Without Ceramic Capacitor C5
VOUT 50mV/DIV IDIODE 500mA/DIV SWITCH VOLTAGE 10V/DIV VIN = 4.1V LOAD = 100mA 100ns/DIV
1610 F08
Figure 8. Switching Waveforms with Ceramic Capacitor C5. Note the 50mV/DIV Scale for VOUT
It is best to choose the compensation components empirically. Once the power components have been chosen (based on size, efficiency, cost and space requirements), a working circuit is built using conservative (or merely guessed) values of RC and CC. Then the response of the circuit is observed under a transient load, and the compen-
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5 SW FB
C3 1F CERAMIC
D1
VOUT 5V 120mA
6 VIN 1 VC LT1610 8 COMP GND 7
1M 2 324k
*
L2 22H
+
SHDN PGND 4
3
C2 22F 6.3V
C5 1F CERAMIC
1610 F06
SHUTDOWN
sation network is modified to achieve stable operation. Linear Technology's Application Note 19 contains a detailed description of the method. A good starting point for the LT1610 is CC ~ 220pF and RC ~ 220k. All Ceramic, Low Profile Design Large value ceramic capacitors that are suitable for use as the main output capacitor of an LT1610 regulator are now available. These capacitors have very low ESR and therefore offer very low output ripple in a small package. However, you should approach their use with some caution. Ceramic capacitors are manufactured using a number of dielectrics, each with different behavior across temperature and applied voltage. Y5V is a common dielectric used for high value capacitors, but it can lose more than 80% of the original capacitance with applied voltage and extreme temperatures. The transient behavior and loop stability of the switching regulator depend on the value of the output capacitor, so you may not be able to afford this loss. Other dielectrics (X7R and X5R) result in more stable characteristics and are suitable for use as the output capacitor. The X7R type has better stability across temperature, whereas the X5R is less expensive and is available in higher values. The second concern in using ceramic capacitors is that many switching regulators benefit from the ESR of the
9
LT1610
APPLICATIONS INFORMATION
output capacitor because it introduces a zero in the regulator's loop gain. This zero may not be effective because the ceramic capacitor's ESR is very low. Most current mode switching regulators (including the LT1610) can easily be compensated without this zero. Any design should be tested for stability at the extremes of operating temperatures; this is particularly so of circuits that use ceramic output capacitors. Figure 9 details a 2.5V to 5V boost converter. Transient response to a 5mA to 105mA load step is pictured in Figure 10. The "double trace" of VOUT at 105mA load is due to the ESR of C2. This ESR aids stability. In Figure 11, C2 is replaced by a 10F ceramic capacitor. Note the low phase margin; at higher input voltage, the converter may oscillate. After replacing the internal compensation network with an external 220pF/220k series RC, the transient response is shown in Figure 12. This is acceptable transient response.
Table 1
FIGURE 10 11 12 C2 AVX TAJA226M006 Tantalum Taiyo Yuden JMK316BJ106 Taiyo Yuden JMK316BJ106
L1 10H VOUT 100mV/DIV LOAD CURRENT 105mA 5mA 500s/DIV
1610 F10
COMPENSATION Internal Internal 220pF/220k
D1
VIN 2.5V 6 VIN 3
5 SW FB LT1610 2
1M
+
SHDN
C1 22F
1
VC COMP 8
GND PGND 4
7
R2 324k
+
RC CC
C1: AVX TAJA226M006 C2: SEE TABLE D1: MOTOROLA MBR0520 L1: MURATA LQH30100
Figure 9. 2.5V to 5V Boost Converter Can Operate with a Ceramic Output Capacitor as Long as Proper RC and CC are Used. Disconnect COMP Pin if External Compensation Components Are Used
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Figure 10. Tantalum Output Capacitor and Internal RC Compensation
VOUT 100mV/DIV
LOAD CURRENT 105mA 5mA 500s/DIV
1610 F11
Figure 11. 10F X5R-Type Ceramic Output Capacitor and Internal RC Compensation has Low Phase Margin
VOUT 100mV/DIV VOUT 5V 100mA
LOAD CURRENT 105mA 5mA 500s/DIV
1610 F12
C2 22F
Figure 12. Ceramic Output Capacitor with 220pF/220k External Compensation has Adequate Phase Margin
1610 F09
LT1610
TYPICAL APPLICATIONS
2-Cell to 5V Converter
L1 4.7H D1
3
+
2 CELLS
SHDN LT1610
FB
2 324k
EFFICIENCY (%)
6 VIN
5 SW
C1 15F
8
COMP VC 1
GND PGND 4
C1, C2: AVX TAJA156M010R D1: MOTOROLA MBR0520 L1: SUMIDA CD43-4R7 MURATA LQH1C4R7
2-Cell to 3.3V Converter
L1 4.7H D1
90
6 1 VIN VC LT1610 8 COMP GND 7
5 SW FB 2
EFFICIENCY (%)
+
2 CELLS
C1 10F
SHDN PGND 4
C1: AVX TAJA106M010R C2: AVX TAJB336M006R D1: MBR0520 L1: MURATA LQH3C4R7
5V to 12V/100mA Boost Converter
L1 10H
D1
VIN 5V 6 1 VIN VC
5 SW FB LT1610 2
EFFICIENCY (%)
+
C1 15F
8
COMP GND 7
SHDN PGND 4
3
C1: AVX TAJA156M010 C2: AVX TAJB156M016 D1: MOTOROLA MBR0520 L1: MURATA LQH3C100M24
SHUTDOWN
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Efficiency
90
VOUT 5V 50mA 1M
VIN = 3V 80 VIN = 2V
+
7
C2 15F
70
VIN = 1.5V
60
50
1610 TA02
0.1
1
100 10 LOAD CURRENT (mA)
1000
1610 TA03
Efficiency
VOUT 3.3V 70mA R2 1M
80 3.3VOUT 3VIN
3
R3 604k
+
C2 33F
70
1.5VIN 2VIN
60
1610 TA04
50 0.1
1
SHUTDOWN
10 LOAD (mA)
100
1000
1610 TA05
Efficiency
90
VOUT 12V 100mA
85 80 75 70 65 60 55 50 0.1
R2 1M
R3 115k
+
C2 15F
1610 TA06
1 10 LOAD CURRENT (mA)
100
1610 TA07
11
LT1610
TYPICAL APPLICATIONS
5V to 9V/150mA Boost Converter
L1 10H D1
90
VIN 5V 6 1 VIN VC
EFFICIENCY (%)
+
C1 15F
LT1610 8 COMP GND 7 SHDN PGND 4 3
C1: AVX TAJA156M010 C2: AVX TAJB156M016 D1: MOTOROLA MBR0520 L1: MURATA LQH3C100M24
VOUT 200mV/DIV LOAD CURRENT 140mA 10mA
INDUCTOR CURRENT 200mA/DIV 200s/DIV
1610 TA10
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Efficiency
VOUT 9V 150mA
85 80 75 70 65 60 55 50
5 SW FB 2
R2 1M
R3 158k
+
C2 15F
1610 TA08
1
SHUTDOWN
10 100 LOAD CURRENT (mA)
300
1610 TA09
5V to 9V Boost Converter Transient Response
LT1610
TYPICAL APPLICATIONS
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: 1F: 4.7F: D1: D2, D3, D4: L1: VIN 3.3V 3 C1 4.7F 100k 51pF TAIYO YUDEN EMK212BJ224MG TAIYO YUDEN LMK212BJ105MG TAIYO YUDEN LMK316BJ475ML MOTOROLA MBRO520 BAT54S SUMIDA CDRH5D185R4 L1 5.4H 6 VIN SHDN LT1610 1 VC GND 7 FB PGND 4 48.7k 2 5 SW COMP 8 274k C2 4.7F 0.22F 1F VON 24V 5mA
AVDD 200mV/DIV VON 500mV/DIV
VOFF 200mV/DIV AVDD LOAD 70mA 25mA VON LOAD = 5mA VOFF LOAD = 5mA 200s/DIV
1610 TA19
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1F
D4 0.22F 1F
D1 AVDD 8V 70mA
1610 TA18
TFT LCD Bias Supply Transient Response
13
LT1610
TYPICAL APPLICATIONS
Single Cell Super Cap Charger
L1 4.7H D1 R4 20 R1 200k 8 Q1
CHARGE 3
SHUTDOWN 1 AA ALKALINE
C1, C2: AVX TAJA156M010 D1: MOTOROLA MBR0530T1 L1: MURATA LQH1C4R7 Q1: 2N3906
Super Cap Charger Output Current vs Output Voltage
25
OUTPUT CURRENT (mA)
20 OUTPUT POWER (mW)
15
10
5
0
2.0
2.5
3.0 3.5 4.0 OUTPUT VOLTAGE (V)
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VOUT 4.5V
6 VIN SHDN LT1610 1 VC GND 7 3.3nF
5 SW COMP
+
C1 15F
+
2
C2 15F
R2 2M
+
CBIG
FB PGND 4
15k
R3 845k
1610 TA11
Super Cap Charger Output Power vs Output Voltage
60 50 40 30 20 10 0
4.5
5.0
2.0
2.5
3.0 3.5 4.0 OUTPUT VOLTAGE (V)
4.5
5.0
1610 TA12
1610 TA13
LT1610
PACKAGE DESCRIPTION
0.007 (0.18)
0.021 0.006 (0.53 0.015)
* DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE ** DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS. INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
0.010 - 0.020 x 45 (0.254 - 0.508) 0.008 - 0.010 (0.203 - 0.254) 0- 8 TYP
0.016 - 0.050 (0.406 - 1.270)
*DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE **DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
U
Dimensions in inches (millimeters) unless otherwise noted. MS8 Package 8-Lead Plastic MSOP
(LTC DWG # 05-08-1660)
0.118 0.004* (3.00 0.102) 8 76 5
0.192 0.004 (4.88 0.10)
0.118 0.004** (3.00 0.102)
1
0.040 0.006 (1.02 0.15)
23
4 0.034 0.004 (0.86 0.102)
0 - 6 TYP SEATING PLANE 0.012 (0.30) 0.0256 REF (0.65) TYP
0.006 0.004 (0.15 0.102)
MSOP (MS8) 1197
S8 Package 8-Lead Plastic Small Outline (Narrow 0.150)
(LTC DWG # 05-08-1610)
0.189 - 0.197* (4.801 - 5.004) 8 7 6 5
0.228 - 0.244 (5.791 - 6.197)
0.150 - 0.157** (3.810 - 3.988)
1 0.053 - 0.069 (1.346 - 1.752)
2
3
4
0.004 - 0.010 (0.101 - 0.254)
0.014 - 0.019 (0.355 - 0.483)
0.050 (1.270) TYP
SO8 0996
15
LT1610
TYPICAL APPLICATIONS N
Li-Ion to 3.3V SEPIC DC/DC Converter
L1 22H C3 1F CERAMIC
6 VIN
5 SW FB LT1610 2
EFFICIENCY (%)
INPUT Li-ION 3V to 4.2V
*
+
C1 22F 6.3V
1
VC
8
COMP GND 7
SHDN PGND 4
C1, C2: AVX TAJB226M006 C3: AVX 1206YC105 (X7R) SHUTDOWN D1: MOTOROLA MBR0520 L1, L2: MURATA LQH3C220 (UNCOUPLED) OR SUMIDA CLS62-220 (COUPLED)
4-Cell to 5V/120mA SEPIC DC/DC Converter
L1 22H C3 1F CERAMIC
*
5 SW FB
6 VIN
EFFICIENCY (%)
+
4 CELLS
C1 22F 6.3V
1
VC LT1610
8
COMP GND 7
SHDN PGND 4
C1, C2: AVX TAJB226M006 C3: AVX 1206YC105 (X7R) SHUTDOWN D1: MOTOROLA MBR0520 L1, L2: MURATA LQH3C220 (UNCOUPLED) OR SUMIDA CLS62-220 (COUPLED)
RELATED PARTS
PART NUMBER LTC 1474 LT1307 LTC1440/1/2 LTC1502-3.3 LT1521 LT1611 LT1613 LTC1682
(R)
DESCRIPTION Micropower Step-Down DC/DC Converter Single Cell Micropower 600kHz PWM DC/DC Converter Ultralow Power Single/Dual Comparators with Reference Single Cell to 3.3V Regulated Charge Pump Micropower Low Dropout Linear Regulator Inverting 1.4MHz DC/DC Converter Step-Up 1.4MHz DC/DC Converter Doubler Charge Pump with Low Noise Linear Regulator
16
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408)432-1900 q FAX: (408) 434-0507 q www.linear-tech.com
U
Efficiency
80
D1 VOUT 3.3V 120mA
70
VIN = 2.7V VIN = 3.6V VIN = 4.2V
1M
*
L2 22H
60
50
604k 3
+
C2 22F 6.3V
40
30 0.1
1610 TA14
1 10 LOAD CURRENT (mA)
100
1610 TA15
4-Cell to 5V Efficiency
80
D1 VOUT 5V 120mA
70
VIN = 3.6V VIN = 4.2V VIN = 5V VIN = 6.5V
1M 2 324k 3
*
L2 22H
60
+
50
C2 22F 6.3V
40
30 0.1
1610 TA16
1 10 LOAD CURRENT (mA)
100
1610 TA17
COMMENTS 94% Efficiency, 10A IQ, 9V to 5V at 250mA 3.3V at 75mA from 1 Cell, MSOP Package 2.8A IQ, Adjustable Hysteresis 40A IQ, No Inductors, 3.3V at 10mA from 1V Input 500mV Dropout, 300mA Current, 12A IQ 5V to - 5V at 150mA, Tiny SOT-23 Package 3.3V to 5V at 200mA, Tiny SOT-23 Package Fixed 3.3V and 5V Outputs, 1.8V to 4.4V Input Range, 50mA Output
1610f LT/TP 0699 4K * PRINTED IN USA
(c) LINEAR TECHNOLOGY CORPORATION 1998

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