LTC3261 High Voltage, Low Quiescent Current Inverting Charge Pump DESCRIPTION FEATURES n n n n n n n 4.5V to 32V VIN Range Inverting Charge Pump Generates –VIN 60μA Quiescent Current in Burst Mode® Operation Charge Pump Output Current Up to 100mA 50kHz to 500kHz Programmable Oscillator Frequency Short-Circuit/Thermal Protection Low Profile Thermally Enhanced 12-Pin MSOP Package APPLICATIONS n n n n Bipolar/Inverting Supplies Industrial/Instrumentation Bias Generators Portable Medical Equipment Portable Instruments The LTC®3261 is a high voltage inverting charge pump that operates over a wide 4.5V to 32V input range and is capable of delivering up to 100mA of output current. The charge pump employs either low quiescent current Burst Mode operation or low noise constant frequency mode. In Burst Mode operation the charge pump VOUT regulates to –0.94 • VIN and the LTC3261 draws only 60μA of quiescent current. In constant frequency mode the charge pump produces an output equal to –VIN and operates at a fixed 500kHz or to a programmed frequency between 50kHz to 500kHz using an external resistor. The LTC3261 is available in a thermally enhanced 12-pin MSOP package. L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks and ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. TYPICAL APPLICATION 15V to –15V Inverter 1μF VOUT Ripple C+ 15V C– –15V VOUT VIN 10μF 10μF VOUT 10mV/DIV AC-COUPLED MODE = L VOUT 200mV/DIV AC-COUPLED MODE = H VOUT = –14.8V LTC3261 EN MODE RT VOUT = –14.1V GND 100μs/DIV 3261 TA01 3261 TA01a VIN = 15V fOSC = 500kHz IOUT = 5mA 3261f 1 LTC3261 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Notes 1, 3) VIN, EN, MODE.. ......................................... –0.3V to 36V VOUT ........................................................... –36V to 0.3V RT ................................................................ –0.3V to 6V VOUT Short-Circuit Duration ............................. Indefinite Operating Junction Temperature Range (Note 2).................................................. –40°C to 125°C Storage Temperature Range ................. –65°C to 150°C Lead Temperature (Soldering, 10 sec)................... 300°C TOP VIEW NC 1 RT 2 NC 3 VOUT 4 C– 5 NC 6 13 GND 12 11 10 9 8 7 NC MODE EN VIN C+ NC MSE PACKAGE 12-LEAD PLASTIC MSOP TJMAX = 150°C, θJA = 40°C/W EXPOSED PAD (PIN 13) IS GND, MUST BE SOLDERED TO PCB ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LTC3261EMSE#PBF LTC3261EMSE#TRPBF 3261 12-Lead Plastic MSOP –40°C to 125°C LTC3261IMSE#PBF LTC3261IMSE#TRPBF 3261 12-Lead Plastic MSOP –40°C to 125°C Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. Consult LTC Marketing for information on non-standard lead based finish parts. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/ 3261f 2 LTC3261 ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C (Note 2). VIN = EN = 12V, MODE = 0V, RT = 200kΩ. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Charge Pump l VIN Input Voltage Range VUVLO VIN Undervoltage Lockout Threshold VIN Rising VIN Falling IVIN VIN Quiescent Current Shutdown, = EN = 0V MODE = VIN, IVOUT = 0mA MODE = 0V, IVOUT = 0mA VRT RT Regulation Voltage VOUT VOUT Regulation Voltage MODE = 12V MODE = 0V l l fOSC Oscillator Frequency RT = GND ROUT Charge Pump Output Impedance MODE = 0V, RT = GND ISHORT_CKT Max IVOUT Short-Circuit Current VOUT = GND, RT = GND 4.5 3.4 450 l VMODE(H) MODE Threshold Rising VMODE(L) MODE Threshold Falling l IMODE MODE Pin Internal Pull-Down Current VEN(H) EN Threshold Rising l VEN(L) EN Threshold Falling l IEN EN Pin Internal Pull-Down Current 100 0.4 VIN = MODE = 32V Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: The LTC3261 is tested under pulsed load conditions such that TJ ≈ TA. The LTC3261E is guaranteed to meet specifications from 0°C to 85°C junction temperature. Specifications over the –40°C to 125°C operating junction temperature range are assured by design, characterization and correlation with statistical process controls. The LTC3261I is guaranteed over the –40°C to 125°C operating junction temperature range. High junction temperatures degrade operating lifetimes; operating lifetime is derated for junction temperatures greater than 125°C. Note that the maximum ambient temperature consistent with these specifications is determined by specific operating conditions in V 4 V V 2 60 3.5 5 120 5.5 V –0.94 • VIN –VIN V V 500 550 KHz Ω 160 250 1.1 2 mA V 1.0 V 0.7 1.1 0.4 μA μA mA 1.200 32 l VIN = EN = 32V 32 3.8 3.6 μA 2 V 1.0 V 0.7 μA conjunction with board layout, the rated package thermal impedance and other environmental factors. The junction temperature (TJ, in °C) is calculated from the ambient temperature (TA, in °C) and power dissipation (PD, in Watts) according to the formula: TJ = TA + (PD • θJA), where θJA = 40°C/W is the package thermal impedance. Note 3: This IC includes overtemperature protection that is intended to protect the device during momentary overload conditions. Junction temperatures will exceed 150°C when overtemperature protection is active. Continuous operation above the specified maximum operating junction temperature may result in device degradation or failure. 3261f 3 LTC3261 TYPICAL PERFORMANCE CHARACTERISTICS (TA = 25°C, CFLY = 1μF, CIN = COUT = 10μF unless otherwise noted) Oscillator Frequency vs Supply Voltage Oscillator Frequency vs RT 400 300 RT = 200kΩ 200 100 0 25 500 SHUTDOWN CURRENT (μA) RT = GND 500 400 300 200 100 0 0 5 10 15 20 25 SUPPLY VOLTAGE (V) 30 35 1 10 100 RT (kΩ) 1000 3261 G01 60 VIN = 5V 40 20 10 8 6 4 5 10 15 20 25 SUPPLY VOLTAGE (V) 3261 G04 30 3 2 0 –50 –25 35 40 35 30 25 200 200 fOSC = 500kHz 150 100 fOSC = 200kHz 50 0 25 50 75 100 125 150 TEMPERATURE (°C) 3261 G07 25 50 75 100 125 150 TEMPERATURE (°C) VOUT Short Circuit Current vs Temperature VOUT SHORT CIRCUIT CURRENT (mA) VOUT SHORT CIRCUIT CURRENT (mA) 45 0 3261 G06 250 0 4 fOSC = 500kHz 50 20 –50 –25 5 VOUT Short-Circuit Current vs Supply Voltage 60 55 fOSC = 500kHz fOSC = 200kHz fOSC = 50kHz 6 3261 G05 Effective Open-Loop Resistance vs Temperature VIN = 32V VIN = 25V VIN = 12V 7 1 0 25 50 75 100 125 150 TEMPERATURE (°C) VIN = 12V 8 0 0 25 50 75 100 125 150 TEMPERATURE (°C) 9 2 0 –50 –25 0 3261 G03 QUIESCENT CURRENT (mA) VIN = 12V 5 Quiescent Current vs Temperature (Constant Frequency Mode) fOSC = 500kHz fOSC = 200kHz fOSC = 50kHz 12 QUIESCENT CURRENT (mA) QUIESCENT CURRENT (μA) 120 80 10 0 –50 –25 10000 14 RT = GND VIN = 32V 15 3261 G02 140 100 VIN = 32V VIN = 12V VIN = 5V 20 Quiescent Current vs Supply Voltage (Constant Frequency Mode) Quiescent Current vs Temperature (Burst Mode Operation) EFFECTIVE OPEN LOOP RESISTANCE (Ω) Shutdown Current vs Temperature 600 OSCILLATOR FREQUENCY (kHz) OSCILLATOR FREQUENCY (kHz) 600 0 5 10 15 20 25 SUPPLY VOLTAGE (V) 30 35 3261 G08 VIN = 12V RT = GND 180 160 140 120 100 –50 –25 0 25 50 75 TEMPERATURE (°C) 100 125 3261 G8b 3261f 4 LTC3261 TYPICAL PERFORMANCE CHARACTERISTICS (TA = 25°C, CFLY = 1μF, CIN = COUT = 10μF unless otherwise noted) Voltage Loss (VIN – |VOUT|) vs Output Current (Constant Frequency Mode) VOUT Load Transient Burst Mode Operation (MODE = H) fOSC = 50kHz fOSC = 200kHz fOSC = 500kHz 2.5 VIN = 12V 2.0 1.5 1.0 0.5 0.0 0.1 EFFECTIVE OPEN LOOP RESISTANCE (Ω) 90 3.0 VOLTAGE LOSS (V) Effective Open-Loop Resistance vs Supply Voltage 80 VOUT 500mV/DIV AC-COUPLED fOSC = 200kHz 70 60 50 –5mA IOUT –50mA fOSC = 500kHz 40 30 20 VIN = 12V fOSC = 500kHz 10 2ms/DIV 3261 G11 0 1 10 OUTPUT CURRENT (mA) 0 100 5 10 15 20 25 SUPPLY VOLTAGE (V) 30 35 3261 G10 3261 G09 Average Input Current vs Output Current VOUT Transient (MODE = Low to High) VOUT Ripple VOUT 500mV/DIV AC-COUPLED MODE VIN = 12V fOSC = 500kHz IOUT = –5mA 2ms/DIV 3261 G12 AVERAGE INPUT CURRENT (mA) 100 10 MODE = L MODE = H VOUT 10mV/DIV AC-COUPLED MODE = L VOUT 200mV/DIV AC-COUPLED MODE = H 1 VIN = 12V fOSC = 500kHz 0.1 0.1 1 10 OUTPUT CURRENT (mA) 100 100μs/DIV 3261 G14 VIN = 15V fOSC = 500kHz IOUT = 5mA 3261 G13 3261f 5 LTC3261 PIN FUNCTIONS NC (Pins 1, 3, 6, 7,12): No Connect Pins. These pins are not connected to the LTC3261 die. These pins should be left floating or connected to ground. Pins 6 and 7 can also be shorted to adjacent pins. VIN (Pin 9): Input Voltage for the Charge Pump. VIN should be bypassed with a low impedance ceramic capacitor. RT (Pin 2): Input Connection for Programming the Switching Frequency. The RT pin servos to a fixed 1.2V when the EN pin is driven to a logic “high”. A resistor from RT to GND sets the charge pump switching frequency. If the RT pin is tied to GND, the switching frequency defaults to a fixed 500kHz. MODE (Pin 12): Logic Input. The MODE pin determines the charge pump operating mode. A logic “high” on the MODE pin forces the charge pump into Burst Mode operation regulating V OUT to approximately –0.94 • VIN with hysteretic control. A logic “low” on the MODE pin forces the charge pump to operate as an openloop inverter with a constant switching frequency. The switching frequency in both modes is determined by an external resistor from the RT pin to GND. In Burst Mode, this represents the frequency of the burst cycles before the part enters the low quiescent current sleep state. EN (Pin 10): Logic Input. A logic “high” on the EN pin enables the inverting charge pump. VOUT (Pin 4): Charge Pump Output Voltage. In constant frequency mode (MODE = low) this pin is driven to –VIN. In Burst Mode operation, (MODE = high) this pin voltage is regulated to –0.94 • VIN using an internal burst comparator with hysteretic control. C– (Pin 5): Flying Capacitor Negative Connection. GND (Exposed Pad Pin 13): Ground. The exposed package pad is ground and must be soldered to the PC board ground plane for proper functionality and for rated thermal performance. C+ (Pin 8): Flying Capacitor Positive Connection. BLOCK DIAGRAM 8 5 C+ 9 VIN C– S1 S4 11 EN MODE 4 S2 S3 10 VOUT CHARGE PUMP AND INPUT LOGIC 50kHz TO 500kHz OSC 13 RT 2 GND 3261 BD 3261f 6 LTC3261 OPERATION (Refer to the Block Diagram) Shutdown Mode In shutdown mode, all circuitry except the internal bias is turned off. The LTC3261 is in shutdown when a logic low is applied to the enable input (EN). The LTC3261 only draws 2μA (typical) from the VIN supply in shutdown. Constant Frequency Operation The LTC3261 provides low noise constant frequency operation when a logic low is applied to the MODE pin. The charge pump and oscillator circuit are enabled using the EN pin. At the beginning of a clock cycle, switches S1 and S2 are closed. The external flying capacitor across the C+ and C– pins is charged to the VIN supply. In the second phase of the clock cycle, switches S1 and S2 are opened, while switches S3 and S4 are closed. In this configuration the C+ side of the flying capacitor is grounded and charge is delivered through the C– pin to VOUT. In steady state the VOUT pin regulates at –VIN less any voltage drop due to the load current on VOUT. The charge transfer frequency can be adjusted between 50kHz and 500kHz using an external resistor on the RT pin. At slower frequencies the effective open-loop output resistance (ROL) of the charge pump is larger and it is able to provide smaller average output current. Figure 1 can be used to determine a suitable value of RT to achieve a required oscillator frequency. If the RT pin is grounded, the part operates at a constant frequency of 500kHz. Burst Mode Operation The LTC3261 provides low power Burst Mode operation when a logic high is applied to the MODE pin. In Burst Mode operation, the charge pump charges the VOUT pin to –0.94 • VIN (typical). The part then shuts down the internal oscillator to reduce switching losses and goes into a low current state. This state is referred to as the sleep state in which the IC consumes only about 60μA. When the output voltage droops enough to overcome the burst comparator hysteresis, the part wakes up and commences charge pump cycles until output voltage exceeds –0.94 • VIN (typical). This mode provides lower operating current at the cost of higher output ripple and is ideal for light load operation. The frequency of charging cycles is set by the external resistor on the RT pin. The charge pump has a lower ROL at higher frequencies. For Burst Mode operation it is recommended that the RT pin be tied to GND. This minimizes the charge pump ROL, quickly charges the output up to the burst threshold and optimizes the duration of the low current sleep state. 600 OSCILLATOR FREQUENCY (kHz) The LTC3261 is a high voltage inverting charge pump. It supports a wide input power supply range from 4.5V to 32V. 500 400 300 200 100 0 1 10 100 RT (kΩ) 1000 10000 3261 F01 Figure 1. Oscillator Frequency vs RT Soft-Start The LTC3261 has built in soft-start circuitry to prevent excessive current flow during start-up. The soft-start is achieved by internal circuitry that slowly ramps the amount of current available at the output storage capacitor. The soft-start circuitry is reset in the event of a commanded shutdown or thermal shutdown. Short-Circuit/Thermal Protection The LTC3261 has built-in short-circuit current limit as well as overtemperature protection. During a short-circuit condition, the part automatically limits its output current to approximately 160mA. If the junction temperature exceeds approximately 175°C the thermal shutdown circuitry disables current delivery to the output. Once the junction temperature drops back to approximately 165°C current delivery to the output is resumed. When thermal protection is active the junction temperature is beyond the specified operating range. Thermal protection is intended for momentary overload conditions outside normal operation. Continuous operation above the specified maximum operating junction temperature may impair device reliability. 3261f 7 LTC3261 APPLICATIONS INFORMATION Effective Open-Loop Output Resistance The effective open-loop output resistance (ROL) of a charge pump is a very important parameter which determines the strength of the charge pump. The value of this parameter depends on many factors such as the oscillator frequency (fOSC), value of the flying capacitor (CFLY), the nonoverlap time, the internal switch resistances (RS) and the ESR of the external capacitors. Typical ROL values as a function of temperature are shown in Figure 2 EFFECTIVE OPEN LOOP RESISTANCE (Ω) 60 55 VIN = 32V VIN = 25V VIN = 12V fOSC = 500kHz 50 45 40 35 30 ⎞ IOUT ⎛ 1 •⎜ – tON ⎟ COUT ⎝ fOSC ⎠ where fOSC is the oscillator frequency tON is the on-time of the oscillator (1μs) typical and COUT is the value of the output capacitor. Just as the value of COUT controls the amount of output ripple, the value of CIN controls the amount of ripple present at the input (VIN) pin. The amount of bypass capacitance required at the input depends on the source impedance driving VIN. For best results it is recommended that VIN be bypassed with at least 2μF of low ESR capacitance. A high ESR capacitor such as tantalum or aluminum will have higher input noise than a low ESR ceramic capacitor. Therefore, a ceramic capacitor is recommended as the main bypass capacitance with a tantalum or aluminum capacitor used in parallel if desired. Flying Capacitor Selection 25 20 –50 –25 VRIPPLE(P-P) ≈ 0 25 50 75 100 125 150 TEMPERATURE (°C) 3261 F02 Figure 2. Typical ROL vs Temperature Input/Output Capacitor Selection The style and value of capacitors used with the LTC3261 determine several important parameters such as regulator control loop stability, output ripple, charge pump strength and minimum turn-on time. To reduce noise and ripple, it is recommended that low ESR ceramic capacitors be used for the charge pump output. The charge pump output capacitor should retain at least 2μF of capacitance over operating temperature and bias voltage. Tantalum and aluminum capacitors can be used in parallel with a ceramic capacitor to increase the total capacitance but should not be used alone because of their high ESR. In constant frequency mode, the value of COUT directly controls the amount of output ripple for a given load current. Increasing the size of COUT will reduce the output ripple at the expense of higher minimum turn-on time. The peak-to-peak output ripple at the VOUT pin is approximately given by the expression: The flying capacitor controls the strength of the charge pump. A 1μF or greater ceramic capacitor is suggested for the flying capacitor for applications requiring the full rated output current of the charge pump. For very light load applications, the flying capacitor may be reduced to save space or cost. For example, a 0.2μF capacitor might be sufficient for load currents up to 20mA. A smaller flying capacitor leads to a larger effective openloop resistance (ROL) and thus limits the maximum load current that can be delivered by the charge pump. Ceramic Capacitors Ceramic capacitors of different materials lose their capacitance with higher temperature and voltage at different rates. For example, a capacitor made of X5R or X7R material will retain most of its capacitance from –40°C to 85°C whereas a Z5U or Y5V style capacitor will lose considerable capacitance over that range. Z5U and Y5V capacitors may also have a poor voltage coefficient causing them to lose 60% or more of their capacitance when the rated voltage is applied. Therefore when comparing different capacitors, it is often more appropriate to compare the amount of achievable capacitance for a given case size rather than discussing the specified capacitance value. The capacitor manufacture’s data sheet 3261f 8 LTC3261 APPLICATIONS INFORMATION should be consulted to ensure the desired capacitance at all temperatures and voltages. Table 1 is a list of ceramic capacitor manufacturers and their websites. The power dissipated in the LTC3261 is: PD = (VIN – |VOUT|) • (IOUT) where IOUT denotes output current at the VOUT pin. Table 1 AVX www.avxcorp.com Kemet www.kemet.com Murata www.murata.com Taiyo Yuden www.t-yuden.com Vishay www.vishay.com TDK www.component.tdk.com Layout Considerations Due to high switching frequency and high transient currents produced by LTC3261, careful board layout is necessary for optimum performance. A true ground plane and short connections to all the external capacitors will improve performance and ensure proper regulation under all conditions. Figure 3 shows an example layout for the LTC3261. The derating curve in Figure 4 assumes a maximum thermal resistance, θJA, of 40°C/W for the package. This can be achieved from a printed circuit board layout with a solid ground plane and a good connection to the exposed pad of the LTC3261 package. It is recommended that the LTC3261 be operated in the region corresponding to TJ ≤ 150°C for continuous operation as shown in Figure 4. Short-term operation may be acceptable for 150°C < TJ < 175°C but long-term operation in this region should be avoided as it may reduce the life of the part or cause degraded performance. For TJ > 175°C the part will be in thermal shutdown. GND The flying capacitor nodes C+ and C– switch large currents at a high frequency. These nodes should not be routed close to sensitive pins such as the RT pin . CFLY VIN At high input voltages and maximum output current, there can be substantial power dissipation in the LTC3261. If the junction temperature increases above approximately 175°C, the thermal shutdown circuitry will automatically deactivate the output. To reduce the maximum junction temperature, a good thermal connection to the PC board ground plane is recommended. Connecting the exposed pad of the package to a ground plane under the device on two layers of the PC board can reduce the thermal resistance of the package and PC board considerably. Derating Power at High Temperatures To prevent an overtemperature condition in high power applications, Figure 4 should be used to determine the maximum combination of ambient temperature and power dissipation. The power dissipated in the LTC3261 should always fall under the line shown for a given ambient temperature. EN MODE RT GND 3261 F03 Figure 3. Recommended Layout 6 MAXIMUM POWER DISSIPATION (W) Thermal Management VOUT θJA = 40°C/W 5 THERMAL SHUTDOWN 4 TJ = 175°C 3 2 RECOMMENDED OPERATION TJ = 150°C 1 0 –50 –25 0 25 50 75 100 125 150 175 AMBIENT TEMPERATURE (°C) 3261 F04 Figure 4. Maximum Power Dissipation vs Ambient Temperature 3261f 9 LTC3261 TYPICAL APPLICATIONS High Input Divide by 2 Voltage Divider C2 1μF 50V C+ 9V TO 32V C– VOUT VIN C1 4.7μF 50V EN LTC3261 MODE RT GND 3261 TA04 VIN/2 C3 4.7μF 25V NOTE: MINIMUM LOAD OF 120μA IS REQUIRED TO ASSURE START-UP Inverting Charge Pump with Bipolar Doubler D1 1N4148 4.5V TO 32V EN C– LTC3261 C4 1μF 50V RT D4 1N4148 –VIN VOUT GND ~ –2VIN C6 4.7μF 100V D3 1N4148 MODE ~ 2VIN C5 4.7μF 100V C2 1μF 50V C3 1μF 50V C VIN C1 4.7μF 50V D2 1N4148 C7 4.7μF 50V 3261 TA06 NOTE: I2VINt*–2VINt*OUT < = 100mA High Voltage to Inverted Low Voltage Charge Pump 4.5V TO 32V C1 4.7μF 50V D1 MBR0540 VIN C4 4.7μF 50V EN C C2 1μF 50V VOUT VOUT + ⎛ V –V – |I | tR ⎞ VOUT – ⎜ IN f OUT OL –Vf ⎟ 2 ⎝ ⎠ LTC3261 D2 MBR0540 C3 1μF 50V D3 MBR0540 C– MODE GND RT 3261 TA07 3261f 10 LTC3261 PACKAGE DESCRIPTION Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. MSE Package 12-Lead Plastic MSOP, Exposed Die Pad (Reference LTC DWG # 05-08-1666 Rev F) BOTTOM VIEW OF EXPOSED PAD OPTION 2.845 ± 0.102 (.112 ± .004) 5.23 (.206) MIN 2.845 ± 0.102 (.112 ± .004) 0.889 ± 0.127 (.035 ± .005) 6 1 1.651 ± 0.102 (.065 ± .004) 1.651 ± 0.102 3.20 – 3.45 (.065 ± .004) (.126 – .136) 12 0.65 0.42 ± 0.038 (.0256) (.0165 ± .0015) BSC TYP RECOMMENDED SOLDER PAD LAYOUT 0.254 (.010) 0.35 REF 4.039 ± 0.102 (.159 ± .004) (NOTE 3) 0.12 REF DETAIL “B” CORNER TAIL IS PART OF DETAIL “B” THE LEADFRAME FEATURE. FOR REFERENCE ONLY 7 NO MEASUREMENT PURPOSE 0.406 ± 0.076 (.016 ± .003) REF 12 11 10 9 8 7 DETAIL “A” 3.00 ± 0.102 (.118 ± .004) (NOTE 4) 4.90 ± 0.152 (.193 ± .006) 0° – 6° TYP GAUGE PLANE 0.53 ± 0.152 (.021 ± .006) 1 2 3 4 5 6 DETAIL “A” 1.10 (.043) MAX 0.18 (.007) SEATING PLANE 0.22 – 0.38 (.009 – .015) TYP 0.650 (.0256) BSC NOTE: 1. DIMENSIONS IN MILLIMETER/(INCH) 2. DRAWING NOT TO SCALE 3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS. INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX 6. EXPOSED PAD DIMENSION DOES INCLUDE MOLD FLASH. MOLD FLASH ON E-PAD SHALL NOT EXCEED 0.254mm (.010") PER SIDE. 0.86 (.034) REF 0.1016 ± 0.0508 (.004 ± .002) MSOP (MSE12) 0911 REV F 3261f 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. 11 LTC3261 TYPICAL APPLICATION 24V to –24V Inverter C2 1μF 8 5 C 9 24V + C– VOUT VIN C1 10μF 4 –24V C3 10μF LTC3261 10 11 EN MODE RT 2 GND 13 3261 TA03 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LTC1144 Switched-Capacitor Wide Input Range Voltage Converter with Shutdown Wide Input Voltage Range: 2V to 18V, ISD < 8μA, SO8 Package LTC1514/LTC1515 Step-Up/Step-Down Switched-Capacitor DC/DC Converters VIN: 2V to 10V, VOUT: 3.3V to 5V, IQ = 60μA, SO8 Package LT®1611 150mA Output, 1.4MHz Micropower Inverting Switching Regulator VIN: 0.9V to 10V, VOUT = ±34V, ThinSOT™ Package LT1614 250mA Output, 600kHz Micropower Inverting Switching Regulator VIN: 0.9V to 6V, VOUT = ±30V, IQ = 1mA, MS8, SO8 Packages LTC1911 250mA, 1.5MHz Inductorless Step-Down DC/DC Converter VIN: 2.7V to 5.5V, VOUT = 1.5V/1.8V, IQ = 180μA, MS8 Package LTC3250/LTC3250-1.2/ Inductorless Step-Down DC/DC Converters LTC3250-1.5 VIN: 3.1V to 5.5V, VOUT = 1.2V, 1.5V, IQ = 35μA, ThinSOT Package LTC3251 500mA Spread Spectrum Inductorless Step-Down DC/DC Converter VIN: 2.7V to 5.5V, VOUT: 0.9V to 1.6V, 1.2V, 1.5V, IQ = 9μA, MS10E Package LTC3252 Dual 250mA, Spread Spectrum Inductorless Step-Down DC/DC Converter VIN: 2.7V to 5.5V, VOUT: 0.9V to 1.6V, IQ = 50μA, DFN12 Package LT1054/LT1054L Switched-Capacitor Voltage Converters with Regulator VIN: 3.5V to 15V/7V, IOUT = 100mA/125mA, N8, S08, SO16 Packages 3261f 12 Linear Technology Corporation LT 0412 • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2012