DC231A

LT1610 1.7MHz, Single Cell Micropower DC/DC Converter U FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ DESCRIPTIO The LT®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. Uses Tiny Capacitors and Inductor Internally Compensated Low Quiescent Current: 30µA 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: < 1µA Automatic Burst ModeTM Switching at Light Load Low VCESAT Switch: 300mV at 300mA 8-Lead MSOP and SO Packages 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 30µA, 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. U APPLICATIO S ■ ■ ■ ■ 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. U ■ TYPICAL APPLICATIO D1 6 3 + 1 CELL C1 22µF FB SHDN GND PGND 1 4 VIN = 1.25V VIN = 1.5V 75 R2 681k COMP VC VOUT = 3V 80 2 LT1610 8 85 R1 1M 5 SW VIN Efficiency VOUT 3V 30mA + 7 C2 22µF EFFICIENCY (%) L1 4.7µH 70 VIN = 1V 65 60 55 C1, C2: AVX TAJA226M006R D1: MOTOROLA MBR0520 L1: MURATA LQH1C4R7 Figure 1. 1-Cell to 3V Step-Up Converter 1610 F01 50 0.1 1 10 LOAD CURRENT (mA) 100 1610 TA01 1 LT1610 U W W W 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 Maximum Junction Temperature ......................... 125°C Operating Temperature Range (Note 1) Commercial ............................................. 0°C to 70°C Extended Commercial (Note 2) .......... – 40°C to 85°C Industrial ........................................... – 40°C to 85°C Storage Temperature Range ................. – 65°C to 150°C Lead Temperature (Soldering, 10 sec).................. 300°C U W U PACKAGE/ORDER INFORMATION ORDER PART NUMBER TOP VIEW VC FB SHDN PGND 1 2 3 4 8 7 6 5 COMP GND VIN SW LT1610CMS8 MS8 PACKAGE 8-LEAD PLASTIC MSOP MS8 PART MARKING TJMAX = 125°C, θJA = 160°C/W LTDT ORDER PART NUMBER TOP VIEW VC 1 8 COMP FB 2 7 GND SHDN 3 6 VIN PGND 4 5 SW LT1610CS8 LT1610IS8 S8 PART MARKING S8 PACKAGE 8-LEAD PLASTIC SO 1610 1610I TJMAX = 125°C, θJA = 120°C/W Consult factory for Military grade parts. ELECTRICAL CHARACTERISTICS The ● denotes specifications which apply over the specified 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 Minimum Operating Voltage TYP 0.9 Maximum Operating Voltage Feedback Voltage ● Quiescent Current VSHDN = 1.5V, Not Switching Quiescent Current in Shutdown VSHDN = 0V, VIN = 2V VSHDN = 0V, VIN = 5V FB Pin Bias Current Reference Line Regulation Error Amp Transconductance 1.20 ● 1V ≤ VIN ≤ 2V (25°C, 0°C) 1V ≤ VIN ≤ 2V (70°C) 2V ≤ VIN ≤ 8V (25°C, 0°C) 2V ≤ VIN ≤ 8V (70°C) ∆I = 2µA 1 V 8 V 1.26 V 30 60 µA 0.5 1.0 µA µA 27 80 nA 0.6 1 2 0.15 0.2 %/V %/V %/V %/V 25 µmhos 100 V/V ● 1.4 1.7 2 MHz 80 ● 77 75 95 95 % % Maximum Duty Cycle 2 UNITS 0.01 0.01 0.03 Error Amp Voltage Gain Switching Frequency 1.23 MAX LT1610 ELECTRICAL CHARACTERISTICS The ● denotes specifications which apply over the specified 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 Switch Current Limit (Note 3) 450 600 900 mA Switch VCESAT ISW = 300mA 300 350 400 mV mV 0.01 1 µA ● Switch Leakage Current VSW = 5V SHDN Input Voltage High 1 V SHDN Input Voltage Low SHDN Pin Bias Current VSHDN = 3V VSHDN = 0V 10 0.01 0.3 V 0.1 µA µA The ● denotes specifications which apply over the specified temperature range, otherwise specifications are at TA = 25°C. Industrial grade – 40°C to 85°C, VIN = 1.5V, VSHDN = VIN, unless otherwise noted. PARAMETER CONDITIONS Minimum Operating Voltage TA = 85°C TA = – 40°C MIN TYP MAX UNITS 0.9 1 1.25 V V 8 V 1.26 V Maximum Operating Voltage Feedback Voltage ● 1.20 Quiescent Current Quiescent Current in Shutdown VSHDN = 0V, VIN = 2V VSHDN = 0V, VIN = 5V FB Pin Bias Current ● Reference Line Regulation 2V ≤ VIN ≤ 8V (– 40°C) 2V ≤ VIN ≤ 8V (85°C) Error Amp Transconductance ∆I = 2µA 30 60 µA 0.01 0.01 0.5 1.0 µA µA 27 80 nA 0.03 0.15 0.2 %/V %/V 100 Switching Frequency (Note 4) Maximum Duty Cycle (Note 4) 1.4 1.7 2 MHz 77 75 80 ● 95 95 % % 450 600 900 mA 300 350 400 mV mV 0.01 1 µA ISW = 300mA ● VSW = 5V SHDN Input Voltage High 1 V SHDN Input Voltage Low SHDN Pin Bias Current V/V ● Switch Current Limit Switch Leakage Current µmhos 25 Error Amp Voltage Gain Switch VCESAT 1.23 VSHDN = 3V VSHDN = 0V 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 0°C to 70°C and is designed, characterized and expected to meet these extended temperature limits, but is not tested at – 40°C and 85°C. The LT1610I is guaranteed to meet the extended temperature limits. 10 0.01 0.3 V 0.1 µA µA 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 85°C. 3 LT1610 U W TYPICAL PERFOR A CE CHARACTERISTICS Current Limit (DC = 30%) vs Temperature VCESAT vs Current 600 Current Limit vs Duty Cycle 800 800 500 VCESAT (mV) TA = 85°C 400 TA = 25°C 300 TA = – 40°C 200 100 0 500 200 300 400 SWITCH CURRENT (mA) 100 700 CURRENT LIMIT (mA) SWITCH CURRENT LIMIT (mA) TA = 25°C 700 600 500 400 300 0 25 50 TEMPERATURE (°C) 75 0 1.50 1.25 1.00 0.75 0.50 40 35 1.230 1.225 1.220 1.215 0 6 4 3 5 INPUT VOLTAGE (V) 7 1.210 –50 8 30 25 20 15 10 5 0.25 2 80 90 100 Quiescent Current vs Temperature QUIESCENT CURRENT (µA) 1.75 10 20 30 40 50 60 70 DUTY CYCLE (%) 1610 G03 1.235 FEEDBACK VOLTAGE (V) SWITCHING FREQUENCY (MHz) 100 1.240 2.00 1 200 Feedback Voltage TA = 25°C 0 300 1610 G02 Oscillator Frequency vs Input Voltage 2.50 400 0 –25 1610 G01 2.25 500 100 200 –50 600 600 –25 0 25 50 TEMPERATURE (°C) 75 100 0 – 50 – 25 0 50 25 TEMPERATURE (°C) 1610 G05 1610 G04 SHDN Pin Current vs SHDN Pin Voltage 75 100 1610 G06 Burst Mode Operation, Circuit of Figure 1 Transient Response, Circuit of Figure 1 SHDN CURRENT (µA) 50 40 VOUT 50mV/DIV AC COUPLED 30 IL1 100mA/DIV ILOAD 20 SWITCH VOLTAGE 2V/DIV SWITCH CURRENT 50mA/DIV 31mA 1mA VIN = 1.25V VOUT = 3V 10 0 0 1 2 4 3 5 6 SHDN VOLTAGE (V) 7 8 1610 G07 4 VOUT 20mV/DIV AC COUPLED 500µs/DIV 1610 TA08 VIN = 1.25V VOUT = 3V ILOAD = 3mA 20µs/DIV 1610 TA08 LT1610 U U U 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. 220kΩ/ 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. 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. PGND (Pin 4): Power Ground. Tie directly to local ground plane. W BLOCK DIAGRA VIN 6 VIN R5 40k VOUT R6 40k + A1 gm R1 (EXTERNAL) FB FB 2 R2 (EXTERNAL) 1 VC – 8 Q1 Q2 × 10 SHUTDOWN COMP 3 SHDN 7 GND RC CC R3 30k R4 140k + ENABLE – BIAS 5 SW – RAMP GENERATOR COMPARATOR FF Σ + A2 R DRIVER Q3 Q S + 0.15Ω A=3 1.7MHz OSCILLATOR – 4 PGND 1610 F02 Figure 2. LT1610 Block Diagram 5 LT1610 U W U U 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 30µA. 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. 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. GROUND PLANE R1 R2 SHUTDOWN VIN 1 8 2 7 LT1610 3 6 4 5 + L1 + MULTIPLE VIAs GND C1 D1 C2 VOUT 1610 F03 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 6 LT1610 U U W U 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 1µF CERAMIC L1 22µH INPUT Li-ION 3V to 4.2V 6 VIN + 1 C1 22µF 6.3V 5 SW VC FB 1M COMP • + 604k SHDN GND PGND 7 4 VOUT 3.3V 120mA L2 22µH 2 LT1610 8 D1 • 3 C2 22µF 6.3V C1, C2: AVX TAJA226M006 C3: AVX 1206YC105 (X7R) SHUTDOWN D1: MOTOROLA MBR0520 L1, L2: MURATA LQH3C220 (UNCOUPLED) OR SUMIDA CLS62-220 (COUPLED) 1610 F04 Figure 4. Li-Ion to 3.3V SEPIC DC/DC Converter GROUND PLANE R1 R2 SHUTDOWN MULTIPLE VIAs VIN 1 8 2 7 LT1610 3 6 4 5 C2 C1 + L1 L2 C3 + GND D1 VOUT 1610 F05 Figure 5. Recommended Component Placement for SEPIC 7 LT1610 U W U U 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 0.5Ω 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 4.7µH or 10µH 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 8 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 1µF ceramic capacitor in parallel with the bulk output capacitor. Ceramic capacitors have very low ESR and 1µF 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. LT1610 U U W U APPLICATIONS INFORMATION L1 22µH • 6 VIN + 4 CELLS C1 22µF 6.3V C4 1µF CERAMIC 1 C3 1µF CERAMIC 5 SW VC 1M FB COMP 324k SHDN GND PGND 7 4 C1, C2: ALUMINUM ELECTROLYTIC C3 TO C5: CERAMIC X7R OR X5R D1: MBR0520 L1, L2: MURATA LQH3C220 OR SUMIDA CLS62-220 3 VOUT 5V 120mA • L2 22µH 2 LT1610 8 D1 + C2 22µF 6.3V C5 1µF CERAMIC 1610 F06 SHUTDOWN Figure 6. 4-Cell Alkaline to 5V/120mA SEPIC DC/DC Converter 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. VOUT 200mV/DIV IDIODE 500mA/DIV SWITCH VOLTAGE 10V/DIV All Ceramic, Low Profile Design 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- 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 U U W U 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 10µF 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. VOUT 100mV/DIV LOAD CURRENT 105mA 5mA 500µs/DIV Figure 10. Tantalum Output Capacitor and Internal RC Compensation VOUT 100mV/DIV LOAD CURRENT 105mA 5mA 500µs/DIV Table 1 FIGURE C2 COMPENSATION 10 AVX TAJA226M006 Tantalum 11 Taiyo Yuden JMK316BJ106 Internal 12 Taiyo Yuden JMK316BJ106 220pF/220k L1 10µH VIN 2.5V 5 SW VIN 3 + C1 22µF FB SHDN RC VC GND COMP 8 VOUT 5V 100mA 2 7 R2 324k + PGND 4 1610 F09 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 10 LOAD CURRENT 105mA 5mA 500µs/DIV C2 22µF CC C1: AVX TAJA226M006 C2: SEE TABLE D1: MOTOROLA MBR0520 L1: MURATA LQH30100 Figure 11. 10µF X5R-Type Ceramic Output Capacitor and Internal RC Compensation has Low Phase Margin VOUT 100mV/DIV 1M LT1610 1 1610 F11 Internal D1 6 1610 F10 1610 F12 Figure 12. Ceramic Output Capacitor with 220pF/220k External Compensation has Adequate Phase Margin LT1610 U TYPICAL APPLICATIONS 2-Cell to 5V Converter 6 VIN 3 + 2 CELLS C1 15µF 90 D1 VOUT 5V 50mA 5 SW 1M 2 FB SHDN LT1610 8 324k COMP VC PGND 1 4 + 7 GND C2 15µF VIN = 3V VIN = 2V 80 EFFICIENCY (%) L1 4.7µH Efficiency VIN = 1.5V 70 60 50 C1, C2: AVX TAJA156M010R D1: MOTOROLA MBR0520 L1: SUMIDA CD43-4R7 MURATA LQH1C4R7 0.1 1 1610 TA02 1 2 CELLS Efficiency 90 D1 6 5 VIN SW 2 R3 604k LT1610 8 COMP SHDN GND PGND 7 4 C1: AVX TAJA106M010R C2: AVX TAJB336M006R D1: MBR0520 L1: MURATA LQH3C4R7 3 3.3VOUT 3VIN 80 R2 1M FB VC VOUT 3.3V 70mA + C2 33µF EFFICIENCY (%) L1 4.7µH C1 10µF 2VIN 60 50 0.1 1610 TA04 SHUTDOWN 100 1000 90 D1 6 5 VIN SW FB VC COMP SHDN GND PGND 7 4 VOUT 12V 100mA R2 1M 2 LT1610 8 10 LOAD (mA) Efficiency 3 R3 115k + C2 15µF 85 80 EFFICIENCY (%) VIN 5V C1 15µF 1 1610 TA05 L1 10µH + 1.5VIN 70 5V to 12V/100mA Boost Converter 1 1000 1610 TA03 2-Cell to 3.3V Converter + 100 10 LOAD CURRENT (mA) 75 70 65 60 55 50 0.1 C1: AVX TAJA156M010 C2: AVX TAJB156M016 D1: MOTOROLA MBR0520 L1: MURATA LQH3C100M24 1610 TA06 SHUTDOWN 1 10 LOAD CURRENT (mA) 100 1610 TA07 11 LT1610 U TYPICAL APPLICATIONS 5V to 9V/150mA Boost Converter VIN 5V 1 + C1 15µF 6 5 VIN SW FB VC COMP SHDN GND PGND 7 4 VOUT 9V 150mA 2 3 R3 158k 85 80 R2 1M LT1610 8 90 D1 + C2 15µF EFFICIENCY (%) L1 10µH Efficiency 75 70 65 60 55 50 C1: AVX TAJA156M010 C2: AVX TAJB156M016 D1: MOTOROLA MBR0520 L1: MURATA LQH3C100M24 1 1610 TA08 SHUTDOWN 300 1610 TA09 5V to 9V Boost Converter Transient Response VOUT 200mV/DIV LOAD CURRENT 140mA 10mA INDUCTOR CURRENT 200mA/DIV 200µs/DIV 12 10 100 LOAD CURRENT (mA) 1610 TA10 LT1610 U TYPICAL APPLICATIONS 3.3V TO 8V/70mA, – 8V/5mA, 24V/5mA TFT LCD Bias Supply Uses All Ceramic Capacitors D2 VOFF – 8V 5mA 1µF D3 0.22µF 0.22µF 0.22µF: 1µF: 4.7µF: D1: D2, D3, D4: L1: TAIYO YUDEN EMK212BJ224MG TAIYO YUDEN LMK212BJ105MG TAIYO YUDEN LMK316BJ475ML MOTOROLA MBRO520 BAT54S SUMIDA CDRH5D185R4 D4 0.22µF L1 5.4µH VIN 3.3V 1µF D1 6 3 1µF AVDD 8V 70mA 5 VIN SW COMP SHDN 8 274k C1 4.7µF C2 4.7µF LT1610 1 100k VON 24V 5mA FB VC GND PGND 7 4 2 48.7k 51pF 1610 TA18 TFT LCD Bias Supply Transient Response AVDD 200mV/DIV VON 500mV/DIV VOFF 200mV/DIV AVDD LOAD 70mA 25mA VON LOAD = 5mA VOFF LOAD = 5mA 200µs/DIV 1610 TA19 13 LT1610 U TYPICAL APPLICATIONS Single Cell Super Cap Charger L1 4.7µH 6 CHARGE 3 + C1 15µF SHUTDOWN 1 AA ALKALINE SW VIN COMP SHDN 15k VC FB GND PGND 7 4 VOUT 4.5V R1 200k 5 Q1 8 + LT1610 1 R4 20Ω D1 R2 2M C2 15µF + CBIG 2 R3 845k 3.3nF 1610 TA11 C1, C2: AVX TAJA156M010 D1: MOTOROLA MBR0530T1 L1: MURATA LQH1C4R7 Q1: 2N3906 Super Cap Charger Output Current vs Output Voltage Super Cap Charger Output Power vs Output Voltage 60 50 20 OUTPUT POWER (mW) OUTPUT CURRENT (mA) 25 15 10 5 0 30 20 10 2.0 2.5 3.0 3.5 4.0 OUTPUT VOLTAGE (V) 4.5 5.0 1610 TA12 14 40 0 2.0 2.5 3.0 3.5 4.0 OUTPUT VOLTAGE (V) 4.5 5.0 1610 TA13 LT1610 U PACKAGE DESCRIPTION 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 7 6 5 0.118 ± 0.004** (3.00 ± 0.102) 0.192 ± 0.004 (4.88 ± 0.10) 1 4 2 3 0.040 ± 0.006 (1.02 ± 0.15) 0.007 (0.18) 0.034 ± 0.004 (0.86 ± 0.102) 0° – 6° TYP SEATING PLANE 0.012 (0.30) 0.0256 REF (0.65) TYP 0.021 ± 0.006 (0.53 ± 0.015) 0.006 ± 0.004 (0.15 ± 0.102) MSOP (MS8) 1197 * 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 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 0.150 – 0.157** (3.810 – 3.988) 0.228 – 0.244 (5.791 – 6.197) 1 0.010 – 0.020 × 45° (0.254 – 0.508) 0.008 – 0.010 (0.203 – 0.254) 0.053 – 0.069 (1.346 – 1.752) 0°– 8° TYP 0.016 – 0.050 (0.406 – 1.270) 0.014 – 0.019 (0.355 – 0.483) *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 2 3 4 0.004 – 0.010 (0.101 – 0.254) 0.050 (1.270) TYP SO8 0996 15 LT1610 U TYPICAL APPLICATIONS N Li-Ion to 3.3V SEPIC DC/DC Converter INPUT Li-ION 3V to 4.2V • 6 VIN + C1 22µF 6.3V 1 5 SW VC FB COMP D1 1M GND PGND 7 4 70 • + 604k SHDN VOUT 3.3V 120mA L2 22µH 2 LT1610 8 80 C3 1µF CERAMIC EFFICIENCY (%) L1 22µH Efficiency 3 C2 22µF 6.3V 60 50 40 30 0.1 C1, C2: AVX TAJB226M006 C3: AVX 1206YC105 (X7R) SHUTDOWN D1: MOTOROLA MBR0520 L1, L2: MURATA LQH3C220 (UNCOUPLED) OR SUMIDA CLS62-220 (COUPLED) 1610 TA15 + 4 CELLS C1 22µF 6.3V 1 5 SW VC FB 8 COMP D1 1M GND PGND 7 4 70 • 324k SHDN VOUT 5V 120mA L2 22µH 2 LT1610 4-Cell to 5V Efficiency EFFICIENCY (%) 6 VIN 100 80 C3 1µF CERAMIC • 1 10 LOAD CURRENT (mA) 1610 TA14 4-Cell to 5V/120mA SEPIC DC/DC Converter L1 22µH VIN = 2.7V VIN = 3.6V VIN = 4.2V + 3 C2 22µF 6.3V C1, C2: AVX TAJB226M006 C3: AVX 1206YC105 (X7R) SHUTDOWN D1: MOTOROLA MBR0520 L1, L2: MURATA LQH3C220 (UNCOUPLED) OR SUMIDA CLS62-220 (COUPLED) VIN = 3.6V VIN = 4.2V VIN = 5V VIN = 6.5V 60 50 40 30 0.1 1 10 LOAD CURRENT (mA) 1610 TA16 100 1610 TA17 RELATED PARTS PART NUMBER ® DESCRIPTION COMMENTS LTC 1474 Micropower Step-Down DC/DC Converter 94% Efficiency, 10µA IQ, 9V to 5V at 250mA LT1307 Single Cell Micropower 600kHz PWM DC/DC Converter 3.3V at 75mA from 1 Cell, MSOP Package LTC1440/1/2 Ultralow Power Single/Dual Comparators with Reference 2.8µA IQ, Adjustable Hysteresis LTC1502-3.3 Single Cell to 3.3V Regulated Charge Pump 40µA IQ, No Inductors, 3.3V at 10mA from 1V Input LT1521 Micropower Low Dropout Linear Regulator 500mV Dropout, 300mA Current, 12µA IQ LT1611 Inverting 1.4MHz DC/DC Converter 5V to – 5V at 150mA, Tiny SOT-23 Package LT1613 Step-Up 1.4MHz DC/DC Converter 3.3V to 5V at 200mA, Tiny SOT-23 Package LTC1682 Doubler Charge Pump with Low Noise Linear Regulator Fixed 3.3V and 5V Outputs, 1.8V to 4.4V Input Range, 50mA Output 16 Linear Technology Corporation 1610f LT/TP 0699 4K • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408)432-1900 ● FAX: (408) 434-0507 ● www.linear-tech.com  LINEAR TECHNOLOGY CORPORATION 1998