LTC3459 10V Micropower Synchronous Boost Converter FEATURES DESCRIPTION n The LTC®3459 is a low current, high efficiency synchronous boost converter intended for low power, size constrained portable applications. The LTC3459 can be powered from a single lithium ion battery, a 2- to 3-cell stack of alkaline or nickel batteries, or any low impedance voltage source between 1.5V and 5.5V. The output is programmable via an external divider between 2.5V and 10V. Although the part is primarily intended for boost applications, VOUT will maintain regulation below VIN (at reduced efficiency). n n n n n n n n n n n Small Solution Size >85% Efficiency over Wide Load Range Internal Synchronous Rectifier VIN Range: 1.5V to 5.5V 5V at 30mA from 3.3V Input 3.3V at 20mA from 2 AA Cell Input Programmable Output Voltages Up to 10V Burst Mode® Operation Inrush Current Limiting Output Disconnect in Shutdown Ultralow Quiescent (10μA) and Shutdown (<1μA) Currents Low Profile 2mm × 2mm DFN, 2mm × 3mm DFN or SOT-23 Package APPLICATIONS n n n n n n The LTC3459 offers Burst Mode operation with a fixed peak current, providing high conversion efficiency over a wide range of load currents. During start-up, inductor current is controlled preventing the inrush surge current found in many boost converters. In shutdown the output is disconnected from the input and quiescent current is reduced to <1μA. The LTC3459 is offered in low profile 6-pin 2mm × 2mm DFN, 2mm × 3mm DFN or SOT-23 (ThinSOT TM) packages, allowing a tiny footprint for the total solution. General Purpose Micropower Boost Digital Cameras PDAs LCD Bias Small OLED Displays Supercap Charging , LT, LTC, LTM and Burst Mode are registered trademarks of Linear Technology Corporation. ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. TYPICAL APPLICATION 5V to 8V Converter Efficiency 100 22μH VIN = 5V VOUT = 8V 5V VIN 2M LTC3459 1μF OFF ON VOUT 8V 30mA VOUT SHDN GND FB 47pF 4.7μF EFFICIENCY (%) 90 SW 80 70 365k 3459 TA01a 60 50 0.01 0.1 1 ILOAD (mA) 10 100 3459 TA01b 3459fc 1 LTC3459 ABSOLUTE MAXIMUM RATINGS Referred to GND (Note 1) VIN, FB Voltage ........................................... –0.3V to 7V VOUT, SHDN Voltage ................................. –0.3V to 10V SW Voltage .............................................. –0.3V to 12V Operating Temperature Range (Notes 2, 3) ......................................... –40°C to 85°C Storage Temperature Range.................. –65°C to 150°C Reflow Temperature .............................................. 260°C Lead Temperature, S6 Package (Soldering, 10 sec) .......................................... 300°C PIN CONFIGURATION TOP VIEW TOP VIEW TOP VIEW VIN 1 VOUT 2 SHDN 3 7 6 SW SHDN 1 5 GND VOUT 2 4 FB DC PACKAGE 6-LEAD (2mm s 2mm) PLASTIC DFN TJMAX = 125°C, θJA = 102°C/W EXPOSED PAD (PIN 7) IS GND, MUST BE SOLDERED TO PCB 6 VIN 7 FB 3 5 GND 4 SW DCB PACKAGE 6-LEAD (2mm × 3mm) PLASTIC DFN TJMAX = 125°C, θJA = 64°C/W EXPOSED PAD (PIN 7) IS GND, MUST BE SOLDERED TO PCB SW 1 GND 2 FB 3 6 VIN 5 VOUT 4 SHDN S6 PACKAGE 6-LEAD PLASTIC TSOT-23 TJMAX = 125°C, θJA = 192°C/W ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LTC3459EDC#PBF LTC3459EDC#TRPBF LDTG Low Profile (2mm × 2mm) Plastic DFN –40°C to 85°C LTC3459EDCB#PBF LTC3459EDCB#TRPBF LDMM Low Profile (2mm × 3mm) Plastic DFN –40°C to 85°C LTC3459ES6#PBF LTC3459ES6#TRPBF LTAHA Low Profile SOT-23 –40°C to 85°C Consult LTC Marketing for parts specified with wider operating temperature ranges. 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/ 3459fc 2 LTC3459 ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 3.3V, VOUT = 5V, unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX UNITS VIN l Input Voltage Range 1.5 5.5 V VIN Quiescent Current SHDN = VCC 10 20 μA VIN Shutdown Current SHDN = GND 0.1 1 μA VOUT l Programmable Voltage Range 10 V VOUT Quiescent Supply Current SHDN = VCC 2.5 2 4 μA VOUT Shutdown Current SHDN = GND 0.1 1 μA 1.22 1.25 V 10 50 nA 60 75 90 mA 225 400 550 ns Reference Feedback Voltage VIN = 3.3V, VOUT = 7.5V FB Input Leakage Current Measured on FB l 1.19 Converter Performance l Peak Switch Current (VIN = 3.3V) L = 22μH tOFF Timer (VIN = 3.3V, VOUT = 5V) Varies by 1/(VOUT – VIN) Zero Current Comparator Threshold L = 22μH 0 mA On-Resistance VOUT = 5V 2.8 Ω Leakage Current VSWITCH = 10V, VOUT = 10V 0.01 On-Resistance VOUT = 5V 4.2 Leakage Current VIN = 5V, VSWITCH = 5V, VOUT = 0V 0.02 Main NMOS Switch 1 μA Main PMOS Switch Ω 2 μA 1 V Logic Inputs SHDN Threshold (Rising Edge) 0.3 SHDN Hysteresis SHDN Input Leakage Current 80 SHDN = 3.3V 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 LTC3459E is guaranteed to meet performance specifications from 0°C to 85°C. Specifications over the –40°C to 85°C operating temperature range are assured by design, characterization and correlation with statistical process controls. 0 mV 50 nA Note 3: This IC includes overtemperature protection that is intended to protect the device during momentary overload conditions. Junction temperature will exceed 125°C when overtemperature protection is active. Continuous operation above the specified maximum operating junction temperature may impair device reliability. 3459fc 3 LTC3459 TYPICAL PERFORMANCE CHARACTERISTICS Minimum ROUT vs VIN 2500 2000 1500 VIN = 3.3V 14 VOUT = 5V VOUT = 10V VOUT = 7.5V VOUT = 5V VOUT = 3.3V L = 22μH 350 300 POUT (mW) ROUT (Ω) 3000 16 400 VOUT = 10V VOUT = 7.5V VOUT = 5V VOUT = 3.3V L = 22μH 3500 VIN and VOUT Quiescent Current vs Temperature Maximum POUT vs VIN 12 CURRENT (μA) 4000 (TA = 25°C, unless otherwise noted). 250 200 150 IIN 10 8 6 1000 100 4 500 50 2 0 1.5 2 2.5 3.5 3 4 4.5 5 0 1.5 5.5 2 2.5 3 VIN (V) 3.5 4 4.5 1.5 2.0 1.5 1.0 0.5 80 N-Channel and P-Channel MOSFET RDS(ON) vs Temperature 6 4.7μF 10μF 22μF 47μF VOUT = 5V L = 22μH VOUT = 5V 5 PCH 4 RDS(ON) (Ω) 2.0 VOUT = 10V VOUT = 7.5V VOUT = 5V VOUT = 3.3V L = 22μH 60 0 40 20 TEMPERATURE (°C) 3459 G03 VOUT Regulation vs VIN and COUT % CHANGE IN VOUT FREQUENCY (MHz) –20 3459 G02 Switching Frequency vs VIN at Various VOUTs 2.5 0 –40 5.5 VIN (V) 3459 G01 3.0 5 IOUT 0 –0.5 NCH 3 2 –1.0 1.0 1 –1.5 0.5 1.5 2 2.5 3 3.5 4 4.5 5 5.5 –2.0 1.5 2 2.5 VIN (V) 3 3.5 4 4.5 5 5.5 0 –40 –20 VIN (V) 3459 G04 40 20 60 0 TEMPERATURE (°C) 3459 G06 3459 G05 Shutdown Threshold Voltage vs Temperature 80 Burst Cycle Switch Pin Waveform SHUTDOWN THRESHOLD VOLTAGE (V) 1.2 1.0 SW CURRENT 50mA/DIV SHDN RISING 0.8 SW CURRENT 50mA/DIV SHDN FALLING 0.6 0.4 0.2 0 –40 INDUCTOR CURRENT 50mA/DIV INDUCTOR CURRENT 50mA/DIV VIN = 3.3V VOUT = 5V L = 22μH –20 40 20 60 0 TEMPERATURE (°C) 1μs/DIV 3459 G08 VIN = 3.3V VOUT = 5V L = 22μH 100ns/DIV 3459 G09 80 3459 G07 3459fc 4 LTC3459 TYPICAL PERFORMANCE CHARACTERISTICS VOUT AC Ripple Burst Cycle VOUT 50mV/DIV INDUCTOR CURRENT 50mA/DIV VIN = 3.3V VOUT = 5V L = 22μH COUT = 4.7μF CFF = 47pF (TA = 25°C, unless otherwise noted). 5μs/DIV Burst Cycle SW CURRENT 50mA/DIV SW CURRENT 50mA/DIV INDUCTOR CURRENT 50mA/DIV INDUCTOR CURRENT 50mA/DIV VIN = 5V VOUT = 10V L = 22μH 3459 G10 VOUT Regulated Below VIN Burst Cycle 1μs/DIV 3459 G11 Shorted Output SW CURRENT 50mA/DIV 1μs/DIV INPUT CURRENT 50mA/DIV VIN = 5V VOUT = 0V L = 22μH 3459 G13 3459 G12 VOUT VOLTAGE 50mA/DIV INDUCTOR CURRENT 50mA/DIV INDUCTOR CURRENT 50mA/DIV 1μs/DIV Start-Up SW CURRENT 50mA/DIV VIN = 5V VOUT = 3.5V L = 22μH VIN = 2V VOUT = 10V L = 22μH 500ns/DIV Load Steps 3459 G14 250μs/DIV VIN = 3.6V VOUT = 0V TO 8V L = 22μH CIN = 2.2μF 3459 G15 Load Steps VOUT AC RIPPLE 50mV/DIV WITH 50kΩ (TRACE 2 GROUNDED) TO 500Ω (TRACE 2 = 5V) VOUT AC RIPPLE 50mV/DIV WITH 5kΩ (TRACE 2 GROUNDED) TO 500Ω (TRACE 2 = 5V) VIN = 3.6V VOUT = 8V L = 22μH COUT = 4.7μF CFF = 47pF 100μs/DIV 3459 G16 VIN = 3.6V VOUT = 8V L = 22μH COUT = 4.7μF CFF = 47pF 100μs/DIV 3459 G17 3459fc 5 LTC3459 PIN FUNCTIONS (DC/DCB/S6 Packages) GND (Pin 5/Pin 5/Pin 2): Signal and Power Ground. Provide a short, direct PCB path between GND and the (–) side of the filter capacitors on VIN and VOUT. VIN (Pin 1/Pin 6/Pin 6): Input Supply Pin. Bypass VIN with a low ESR, ESL ceramic capacitor of at least 1μF. VOUT (Pin 2/Pin 2/Pin 5): Regulated Output Voltage of the Boost Regulator. Bypass VOUT with a low ESR, ESL ceramic capacitor between 2.2μF and 10μF. VOUT ripple increases with smaller capacitors. SW (Pin 6/Pin 4/Pin 1): Switch Pin. Connect a 15μH to 33μH inductor between SW and VIN. Keep PCB trace lengths as short and wide as possible to reduce EMI and voltage overshoot. If the inductor current falls to zero, the internal P-channel MOSFET synchronous rectifier is turned off to prevent reverse charging of the inductor. SHDN (Pin 3/Pin 1/Pin 4): Master Shutdown Input. Driving SHDN low disables all IC functions and reduces quiescent current from the battery to less than 1μA. This pin must be pulled above 1V to enable the IC. Exposed Pad (Pin 7/Pin 7, DC and DCB Packages Only): Ground. The Exposed Pad must be soldered to PCB. FB (Pin 4/Pin 3/Pin 3): Input to the Burst Mode Comparator. An external resistor divider connected between VOUT, GND and this pin sets the output voltage to: VOUT = 1.22(1 + R1/R2) BLOCK DIAGRAM VCC SW + Q SD IPEAK IZO QB R Q P/~N IZERO DETECT VBEST SW1 S VOUT QB RD IZO S VIN – tOFF tOFF TIMER VOUT VSELECT VSELECT Q THERMAL SD SLEEP DELAY P-DRIVE R1 RD QB – VBEST R2 HYSTCOMP IPEAK DETECT + VCC FB VCC N-DRIVE REFOK N-DRIVE SDB P-DRIVE REFERENCE SD SD SDB GND SHDN 3459 BD OFF ON 3459fc 6 LTC3459 OPERATION Operation The LTC3459 synchronous boost converter utilizes a Burst Mode control technique to achieve high efficiency over a wide dynamic range. A 2.5% accurate comparator is used to monitor the output voltage (VOUT), if VOUT is above the comparator threshold, no switching occurs and only quiescent current (10μA) is drawn from the power source. When VOUT drops below the comparator threshold, switching commences and the output capacitor is charged. During the on time of the switching period, inductor current is ramped through an internal N-channel MOSFET to GND until a peak current (75mA) is detected. A P-channel MOSFET connects the inductor to VOUT during the off time delivering energy to the load. The off time is controlled by an internal timer which is proportional to 1/(VOUT – VIN). Anticross conduction circuitry ensures the N- and P-channel switches are never on simultaneously. Only three power components and two feedback resistors are required to complete the design of the boost converter, an external Schottky diode is not required. The high operating frequency allows the use of low value, low profile inductors and tiny external ceramic capacitors. The boost converter disconnects VOUT from VIN during shutdown to avoid loading the input power source. Peak Current Overshoot The LTC3459’s peak current comparator has a delay of approximately 100ns from the time inductor current reaches current limit until the internal N-channel MOSFET turns off. This delay causes the peak current to overshoot based on the inductor value and VIN, as follows (Figure 2 is based on a 65mA initial ILIMIT). V IPEAK = ILIMIT + (100ns) IN L tOFF Timer The LTC3459’s tOFF timer is designed to keep the inductor current continuous during a Burst Mode switching packet, thereby increasing current capability at the output. A larger inductor value will have lower peak-to-peak current ripple, increasing the available current to the load. This improvement is offset somewhat by the reduced IPEAK overshoot. The tOFF timer is designed to maintain a relatively constant peak-to-peak current in the inductor despite VIN changes. ~50mVP-P VOUT AC RIPPLE IPEAK tOFF N P tOFF N P ~100mA tOFF N P N P IZERO WAIT BURST ON N SLEEP tOFF P N BURST ON 3459 F01 Figure 1. Inductor Current and VOUT Ripple Waveforms 0.8 110 0.7 100 0.6 15μH 0.5 22μH tOFF (μs) IPEAK (mA) 90 80 33μH 0.4 0.3 70 0.2 60 0.1 50 1.5 2 2.5 3 4 3.5 VIN (V) 4.5 5 5.5 3459 F02 Figure 2. Typical IPEAK Values 0 0.5 1.5 2.5 3.5 4.5 5.5 VOUT – VIN (V) 6.5 7.5 8.5 3459 F03 Figure 3. tOFF Times 3459fc 7 LTC3459 OPERATION This is accomplished by varying the tOFF period by approximately 1/(VOUT – VIN). Due to propagation delays and a 0.6μA bias current in the timer, the tOFF time can be more accurately predicted as follows: tOFF ≈ 100ns + 0.8 pF • 1.25V V –V 0.6μA + OUT IN 500k If VOUT is less than VIN, the tOFF delay is fixed at approximately 750ns. APPLICATIONS INFORMATION Inductor Selection Capacitor Selection An inductor with a minimum value of 15μH is recommended for use with the LTC3459. Values larger than 15μH will result in lower ripple current and switching frequency. High frequency ferrite core materials are strongly recommended. Some inductors meeting these requirements are listed in Table 1. The boost converter requires two capacitors. The input capacitor should be an X5R type of at least 1.0μF. The VOUT capacitor should also be an X5R type between 2.2μF and 10μF. A larger capacitor should be used if lower peak-topeak output ripple and better line regulation is desired. Table 1. Example Inductors SUPPLIER VENDOR/PART L DCR (Ω)/ (μH) IMAX (mA) DIMENSIONS (mm) CONTACT INFORMATION Chip Inductors Murata LQH31C LQH32C-Low Profile Taiyo Yuden LB2016 Toko LLB2520 Coilcraft DO3314 DO1606T Sumida CMD4D06 CDRJ2D1BLD www.murata.com 22 22 3/160 0.7/250 3.2 × 1.6 × 1.8 3.2 × 2.5 × 1.6 15 22 33 0.7/130 1/105 1.7/85 2.0 × 1.6 × 1.6 www.t-yuden.com (408) 573-4150 15 22 33 1.7/180 2.5/160 3.8/130 2.5 × 2.0 × 1.6 www.tokoam.com (847) 297-0070 15 22 15 22 33 0.86/650 1.2/500 0.4/700 0.5/500 0.74/450 3.3 × 3.3 × 1.4 www.coilcraft.com (847) 639-6400 15 22 33 15 22 33 0.5/400 6.6 × 5.8 × 0.8 0.8/300 1.3/240 0.175/350 3.2 × 3.2 × 2.0 0.255/300 0.37/240 Table 2. Capacitor Vendor Information PHONE WEBSITE AVX (803) 448-9411 www.avxcorp.com Murata (714) 852-2001 www.murata.com Taiyo Yuden (408) 573-4150 www.t-yuden.com TDK (847) 803-6100 www.component.tdk.com PCB Layout Guidelines The high speed operation of the LTC3459 demands careful attention to board layout. You will not get advertised performance with a careless layout. Figure 4 shows the recommended component placement for the TSOT version of the part. A large ground pin copper area will help to lower the chip temperature. RECOMMENDED COMPONENT PLACEMENT. TRACES CARRYING CURRENT ARE DIRECT. TRACE AREA AT FB PIN IS SMALL. LEAD LENGTH TO BATTERY IS SHORT 6.5 × 5.3 × 2.0 www.sumida.com (847) 956-0666 VIN 1 SW VIN 6 2 GND VOUT 5 3 FB SHDN 4 SHDN VOUT 3459 F04 Figure 4. Recommended Component Placement for a Single-Layer Board 3459fc 8 LTC3459 TYPICAL APPLICATIONS Very low operating quiescent current and synchronous operation allow for greater than 85% conversion efficiency in many applications. Lower output voltages will result in lower efficiencies since the N- and P-channel RDS(ON)s will increase. The switching frequency and output power capability of the LTC3459 are also dependant on input and output voltages. The LTC3459 is designed to control peak inductor current when VIN is greater than or less than VOUT. This allows current to be controlled during start-up in a boost application, for example, or VOUT to be regulated below VIN when powered from a fresh battery. Peak current control makes the LTC3459 an ideal candidate for charging a back-up source such as a SuperCap. Figure 5 shows an application where the LTC3459 is used to charge a two-farad, 5V SuperCap from a 3.3V input. A NiCd battery could be charged by the LTC3459 as well, but that application may require additional circuitry for proper charge termination. Charging a SuperCap® SuperCaps have become a popular alternative to NiCd batteries as back-up power sources in portable equipment. Capacitance values of one farad and higher are achievable in small package sizes with leakage currents in the low microamps. SuperCaps are typically charged at low currents for several minutes until they reach the required back-up voltage. When VOUT is less than ~3.5V, the body of the internal synchronous P-channel MOSFET rectifier is connected to VIN, and the SW pin rises a diode above VIN when current is delivered to the load. While efficiency is compromised in this mode of operation, current to the SuperCap is 5V from Li-Ion Input 100 15μH* Li-Ion BATTERY VIN + VOUT FB SHDN GND OFF ON 47pF 1M LTC3459 1μF VOUT 5V 4.7μF 332k VIN = 4.2V 90 EFFICIENCY (%) SW VIN 2.5V TO 4.2V VOUT = 5V VIN = 2.5V 80 70 3459 TA04a *COILCRAFT DO3314 60 50 0.01 0.1 1 ILOAD (mA) 10 100 3459 TA04b 10V from 3.3V or 5V Input 100 33μH* VOUT VIN 2M LTC3459 1μF OFF ON VOUT 10V SHDN GND 47pF 4.7μF FB 280k 3459 TA05a *COILCRAFT DO3314 EFFICIENCY (%) 90 SW VIN 3.3V TO 5V VOUT = 10V VIN = 5V 80 VIN = 3.3V 70 60 50 0.01 0.1 1 ILOAD (mA) 10 100 3459 TA05b 3459fc 9 LTC3459 TYPICAL APPLICATIONS controlled, preventing any damaging effects of inrush current. Proper heat sinking of the package is required in this application as the die may dissipate 100mW to 200mW during initial charging. When VOUT is greater than ~3.5V, normal boost mode operation and efficiency begin, with the P-channel MOSFET acting as a synchronous switch. Average input current is a constant 50mA during charging, where the current delivered to the SuperCap varies somewhat with duty cycle. Once the SuperCap is charged to 5V, the LTC3459 begins to regulate and the input current is reduced to the amount required to support the load and/or self discharge of the SuperCap. L1 SW VIN 1μF 3.3V LTC3459 + OFF ON VOUT 5V VOUT FB SHDN GND 1M 1μF COUT 2F 332k 3459 F05 COUT: MAXWELL TECHNOLOGIES ULTRACAP PC5-5, 2F, 5V L1: 33μH, 1.7Ω TAIYO YUDEN LB2016 Figure 5. Charging a SuperCap from a 3.3V Source PACKAGE DESCRIPTION DC Package 6-Lead Plastic DFN (2mm × 2mm) (Reference LTC DWG # 05-08-1703) R = 0.115 TYP 0.56 p 0.05 (2 SIDES) 0.675 p0.05 2.50 p0.05 1.15 p0.05 0.61 p0.05 (2 SIDES) PACKAGE OUTLINE PIN 1 BAR TOP MARK (SEE NOTE 6) 0.38 p 0.05 4 2.00 p0.10 (4 SIDES) PIN 1 CHAMFER OF EXPOSED PAD 3 0.25 p 0.05 0.50 BSC 1.42 p0.05 (2 SIDES) 0.200 REF RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS 6 0.75 p0.05 1 (DC6) DFN 1103 0.25 p 0.05 0.50 BSC 1.37 p0.05 (2 SIDES) 0.00 – 0.05 BOTTOM VIEW—EXPOSED PAD NOTE: 1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WCCD-2) 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE 5. EXPOSED PAD SHALL BE SOLDER PLATED 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE 3459fc 10 LTC3459 PACKAGE DESCRIPTION DCB Package 6-Lead Plastic DFN (2mm × 3mm) (Reference LTC DWG # 05-08-1715) R = 0.115 TYP R = 0.05 TYP 2.00 ±0.10 (2 SIDES) 0.70 ±0.05 3.55 ±0.05 PACKAGE OUTLINE 1.65 ±0.05 (2 SIDES) 3.00 ±0.10 (2 SIDES) 0.40 ± 0.10 4 6 1.65 ± 0.10 (2 SIDES) 2.15 ±0.05 PIN 1 NOTCH R0.20 OR 0.25 × 45° CHAMFER PIN 1 BAR TOP MARK (SEE NOTE 6) 3 0.25 ± 0.05 0.50 BSC 1.35 ±0.05 (2 SIDES) 0.25 ± 0.05 0.50 BSC 0.75 ±0.05 0.200 REF (DCB6) DFN 0405 1 1.35 ±0.10 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS 0.00 – 0.05 NOTE: 1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (TBD) 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE BOTTOM VIEW—EXPOSED PAD 5. EXPOSED PAD SHALL BE SOLDER PLATED 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE S6 Package 6-Lead Plastic TSOT-23 (Reference LTC DWG # 05-08-1636) 0.62 MAX 2.90 BSC (NOTE 4) 0.95 REF 1.22 REF 3.85 MAX 2.62 REF 1.4 MIN 2.80 BSC 1.50 – 1.75 (NOTE 4) PIN ONE ID RECOMMENDED SOLDER PAD LAYOUT PER IPC CALCULATOR 0.30 – 0.45 6 PLCS (NOTE 3) 0.95 BSC 0.80 – 0.90 0.20 BSC 0.01 – 0.10 1.00 MAX DATUM ‘A’ 0.30 – 0.50 REF NOTE: 1. DIMENSIONS ARE IN MILLIMETERS 2. DRAWING NOT TO SCALE 3. DIMENSIONS ARE INCLUSIVE OF PLATING 0.09 – 0.20 (NOTE 3) 1.90 BSC S6 TSOT-23 0302 REV B 4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR 5. MOLD FLASH SHALL NOT EXCEED 0.254mm 6. JEDEC PACKAGE REFERENCE IS MO-193 3459fc 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 LTC3459 TYPICAL APPLICATION 3.3V from a 2 AA Alkaline Input L1 15μH SW + C1 2.2μF + OFF ON VOUT VIN R1 604k LTC3459 SHDN C2 47pF C3 4.7μF FB R2 365k GND VOUT = 3.3V 90 VOUT 3.3V VIN = 3V EFFICIENCY (%) VIN 1.8V TO 3V 2 AA CELLS 100 80 VIN = 1.8V 70 3459 TA06a 60 C1: TDK C1608X5R1A225MT C2: TDK C0603COG1E470J C3: TDK C2012X5ROJ475K L1: COILCRAFT DO3314-153MXB R1: PANASONIC ERJ3EKF6043V R2: PANASONIC ERJ3EKF3653V 50 0.01 0.1 1 ILOAD (mA) 10 100 3459 TA06b RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1310 1.5A ISW, 4.5MHz, High Efficiency Step-Up DC/DC Converter VIN: 2.75V to 18V, VOUT(MAX) = 35V, IQ = 12mA, ISD < 1μA, MS10E LT1613 550mA ISW, 1.4MHz, High Efficiency Step-Up DC/DC Converter VIN: 0.9V to 10V, VOUT(MAX) = 34V, IQ = 3mA, ISD < 1μA, ThinSOT LT1615/ LT1615-1 300mA/80mA ISW, Constant Off-Time, High Efficiency Step-Up DC/DC Converter VIN: 1.2V to 15V, VOUT(MAX) = 34V, IQ = 20μA, ISD < 1μA, ThinSOT LT1618 1.5A ISW, 1.4MHz, High Efficiency Step-Up DC/DC Converter VIN: 1.6V to 18V, VOUT(MAX) = 35V, IQ = 1.8mA, ISD < 1μA, MS10 LT1944 (Dual) Dual Output 350mA ISW, Constant Off-Time, High Efficiency Step-Up DC/DC Converter VIN: 1.2V to 15V, VOUT(MAX) = 34V, IQ = 20μA, ISD < 1μA, MS10 LT1945 (Dual) Dual Output Pos/Neg 350mA ISW, Constant Off-Time, High Efficiency Step-Up DC/DC Converter VIN: 1.2V to 15V, VOUT(MAX) = ±34V, IQ = 20μA, ISD < 1μA, MS10 LT1946/ LT1946A 1.5A ISW, 1.2MHz/2.7MHz, High Efficiency Step-Up DC/DC Converter VIN: 2.45V to 16V, VOUT(MAX) = 34V, IQ = 3.2mA, ISD < 1μA, MS8 LT1949/ LT1949-1 550mA ISW, 600kHz/1.1MHz, High Efficiency Step-Up DC/DC Converter VIN: 1.5V to 12V, VOUT(MAX) = 28V, IQ = 4.5mA, ISD < 25μA, SO-8, MS8 LT1961 1.5A ISW, 1.25MHz, High Efficiency Step-Up DC/DC Converter VIN: 3V to 25V, VOUT(MAX) = 35V, IQ = 0.9mA, ISD < 6μA, MS8E LTC3400/ LTC3400B 600mA ISW, 1.2MHz, Synchronous Step-Up DC/DC Converter VIN: 0.5V to 5V, VOUT(MAX) = 5V, IQ = 19μA/300μA, ISD < 1μA, ThinSOT LTC3401 1A ISW, 3MHz, Synchronous Step-Up DC/DC Converter VIN: 0.5V to 5V, VOUT(MAX) = 6V, IQ = 38μA, ISD < 1μA, MS10 LTC3402 2A ISW, 3MHz, Synchronous Step-Up DC/DC Converter VIN: 0.5V to 5V, VOUT(MAX) = 6V, IQ = 38μA, ISD < 1μA, MS10 LTC3425 5A ISW, 8MHz, 4-Phase Synchronous Step-Up DC/DC Converter, QFN32 VIN: 0.5V to 4.5V, VOUT(MAX) = 5.25V, IQ = 12μA, ISD < 1μA, LTC3429 600mA, 500kHz, Synchronous Step-Up DC/DC Converter with Output Disconnect and Soft-Start VIN: 0.5V to 5V, VOUT(MAX) = 5V, IQ = 20μA/300μA, ISD < 1μA, ThinSOT LT3460 320mA ISW, 1.3MHz, High Efficiency Step-Up DC/DC Converter VIN: 0.5V to 5V, VOUT(MAX) = 5V, IQ = 20μA/300μA, ISD < 1μA, ThinSOT LT3464 85mA ISW, Constant Off-Time, High Efficiency Step-Up DC/DC Converter with Integrated Schottky/Output Disconnect VIN: 2.3V to 10V, VOUT(MAX) = 34V, IQ = 25μA, ISD < 1μA, ThinSOT 3459fc 12 Linear Technology Corporation LT 1208 REV C • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2007