LTC3525DESC6-3.3

LTC3525D-3.3 400mA Micropower Synchronous Step-Up DC/DC Converter with Pass Through Mode FEATURES ■ ■ ■ ■ ■ DESCRIPTIO ■ ■ ■ ■ ■ ■ ■ ■ VOUT Connected to VIN in Shutdown Up to 95% Efficiency 0.85V Minimum Input Start-Up Voltage Fixed Output Voltage of 3.3V Delivers 60mA at 3.3V from a 1V Input, or 140mA at 3.3V from a 1.8V Input Burst Mode® Operation: IQ = 7µA VIN Range: 0.5V to 4.5V Only Three External Components VIN > VOUT Operation Antiringing Control Short-Circuit and Overtemperature Protection Very Low Profile of 1mm Tiny 6-Pin SC70 Package The LTC®3525D-3.3 is a high efficiency synchronous stepup DC/DC converter that can start up with an input as low as 0.85V. It offers a compact, high efficiency alternative to charge pumps in single cell or dual cell alkaline or Li-ion applications. Only three small external components are required. The LTC3525D features a fixed output voltage of 3.3V. In shutdown, VOUT is connected to VIN through the inductor. The device includes a 0.5Ω N-channel MOSFET switch and a 0.8Ω P-channel synchronous rectifier. Peak switch current ranges from 150mA to 400mA, depending on load, providing enhanced efficiency. Quiescent current is an ultralow 7µA, maximizing battery life in portable applications. Other features include anti-ringing control and thermal shutdown. The LTC3525D is available in a tiny 6-pin SC70 package. , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. Burst Mode is a registered trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Patents Pending. APPLICATIO S ■ ■ ■ ■ MP3 Players Portable Instruments Glucose Meters Digital Cameras TYPICAL APPLICATIO LTC3525D-3.3 Efficiency and Power Loss vs Load Current L1* 10µH 100 90 LTC3525D-3.3 VIN 1.8V to 3.2V PASS THROUGH ON 1µF SHDN GND VOUT GND VIN SW VOUT 3.3V 140mA 10µF 80 EFFICIENCY (%) EFFICIENCY 70 60 POWER LOSS 50 40 3525 TA01 30 20 0.01 0.1 1 10 LOAD (mA) *MURATA LQH32CN100K53 U 100 10 POWER LOSS (mW) 1 0.1 VIN = 3V VIN = 2.4V VIN = 1.2V 100 0.01 1000 LT3525 • TA02 U U 3525d33f 1 LTC3525D-3.3 ABSOLUTE (Note 1) AXI U RATI GS PACKAGE/ORDER I FOR ATIO TOP VIEW SHDN 1 GND 2 VIN 3 6 SW 5 GND 4 VOUT VIN, VOUT Voltage ........................................ –0.3V to 6V SW Voltage ................................................. –0.3V to 6V SW Voltage < 100ns ................................... –0.3V to 7V ⎯S⎯H⎯D⎯N Voltage ............................................. –0.3V to 6V Operating Temperature Range (Notes 2, 5).......................................... –40°C to 85°C Storage Temperature Range................... –65°C to 125°C Lead Temperature (Soldering, 10 sec) .................. 300°C SC6 PACKAGE 6-LEAD PLASTIC SC70 TJMAX = 125°C θJA = 256°C/W IN FREE AIR, θJA = 150°C/W ON BOARD OVER GROUND PLANE ORDER PART NUMBER LTC3525DESC6-3.3 SC6 PART MARKING LCQZ Order Options Tape and Reel: Add #TR Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF Lead Free Part Marking: http://www.linear.com/leadfree/ Consult LTC Marketing for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 1.2V, V⎯S⎯H⎯D⎯N = 1.2V, VOUT = 3.3V unless otherwise noted. PARAMETER Input Start-Up Voltage Output Voltage Quiescent Current, VOUT Quiescent Current, VIN Quiescent Current, VIN - Shutdown NMOS Switch On Resistance PMOS Switch On Resistance Peak Current Limit ⎯SH⎯D⎯N Threshold ⎯ ⎯SH⎯D⎯N Input Current ⎯ V⎯S⎯H⎯D⎯N = VIN or VOUT (Note 6) ⎯S⎯H⎯D⎯N = VIN (Note 4) ⎯S⎯H⎯D⎯N = VIN (Note 4) ⎯S⎯H⎯D⎯N = 0V, VOUT = VIN = 3.3V Including Switch Leakage (Note 3) (Note 3) 0.4 0.4 ● CONDITIONS MIN 3.20 TYP 0.85 3.30 7 0.5 3 0.5 0.8 0.45 0.6 0.01 MAX 1 3.40 15 3 10 UNITS V V µA µA µA Ω Ω A 1 1 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 LTC3525DE 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. Note 3: Specification is guaranteed by design and not 100% tested in production. Note 4: Current Measurements are performed when the LTC3525D is not switching. Note 5: 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. Note 6: Consult LTC Marketing for other output voltage options. 3525d33f 2 U V µA W U U WW W LTC3525D-3.3 TYPICAL PERFOR A CE CHARACTERISTICS TA = 25°C unless otherwise noted. Maximum Output Current vs VIN (for VOUT to Drop 2.5%) 300 250 200 LOAD (mA) IOUT (mA) IIN (µA) 150 150 100 50 0 0.5 50 250 1.0 1.5 2.0 2.5 3.0 VIN (V) 3.5 Efficiency and Power Loss vs Load 100 90 80 EFFICIENCY (%) EFFICIENCY 70 60 POWER LOSS 50 40 30 20 0.01 0.1 1 10 LOAD (mA) VIN = 3V VIN = 2.4V VIN = 1.2V 100 0.1 1 10 POWER LOSS (mW) 100 CHANGE IN VOUT (%) 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 –2.5 0 10 20 30 40 50 LOAD (mA) 60 70 80 COUT = 10µF COUT = 22µF CHANGE IN VOUT (%) Light Load Burst Frequency vs Load 40 35 BURST FREQUENCY (kHz) CHANGE IN VOUT (%) 30 25 20 15 10 5 0 0.1 1 LOAD (mA) 10 3525 G12 SWITCHING DELAY (µs) COUT = 10µF COUT = 22µF UW 4.0 3525 G01 3525 G04 Maximum Startup Load vs VIN (Resistive Load) 50 45 200 40 35 30 25 20 15 10 5 0 4.5 0.5 1.0 1.5 2.0 VIN (V) 2.5 3.0 3525 G02 No-Load Input Current vs VIN 100 0 1.0 1.5 2.0 2.5 3.0 VIN (V) 3.5 4.0 4.5 3525 G03 Load Regulation 2.5 2.0 1.5 VIN = 1.2V 2.5 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 –2.5 Load Regulation VIN = 2.4V COUT = 22µF COUT = 10µF 0.01 1000 0 20 40 60 80 100 120 140 160 180 LOAD (mA) 3525 G07 3525 G06 VOUT Variation vs Temperature (Normalized to 25°C) 0.4 0.3 0.2 0.1 0 –0.1 –0.2 –0.3 –0.4 –40–30–20–10 0 10 20 30 40 50 60 70 80 TEMPERATURE (°C) 3525 G13 Start-Up Delay Coming Out of Shutdown 120 100 80 60 40 20 0 1.0 1.5 2.0 2.5 3.0 VIN (V) 3.5 4.0 4.5 3525 G14 3525d33f 3 LTC3525D-3.3 TYPICAL PERFOR A CE CHARACTERISTICS TA = 25°C unless otherwise noted. Output Voltage Ripple IOUT = 5mA IOUT = 40mA IOUT = 80mA 50µs/DIV 3525 G16 VIN = 1.2V COUT = 10µF Output Voltage Ripple IOUT = 5mA IOUT = 100mA IOUT = 190mA 50mV/DIV VIN = 2.4V COUT = 22µF 50µs/DIV 4 UW Output Voltage Ripple IOUT = 5mA 50mV/DIV IOUT = 40mA IOUT = 80mA 50µs/DIV 3525 G17 50mV/DIV VIN = 1.2V COUT = 22µF 50mA Load Step Response OUTPUT RIPPLE 50mV/DIV LOAD CURRENT 20mA/DIV 3525 G18 VIN = 1.2V COUT = 22µF 500µs/DIV 3525 G21 100mA Load Step Response OUTPUT RIPPLE 50mV/DIV LOAD CURRENT 50mA/DIV 500µs/DIV 3525 G22 VIN = 2.4V COUT = 22µF 3525d33f LTC3525D-3.3 PI FU CTIO S ⎯S⎯H⎯D⎯N (Pin 1): Logic Controlled Shutdown Input. Connect to a voltage >1V to enable the LTC3525D. Connect to a voltage