Part: LTC3105 — Linear Technology Corporation

Type: Synchronous Step-Up DC/DC Converter

Description: A high efficiency step-up DC/DC converter with 250mV start-up capability, 225mV to 5V input range, integrated maximum power point controller, and an auxiliary 6mA LDO regulator, optimized for energy harvesting applications.

Operating Conditions:

• Supply voltage: 0.225–5 V
• Operating junction temperature: -40 to 85 °C
• Output voltage adjust range: 1.6–5.25 V
• LDO output adjust range: 1.4–5 V

Absolute Maximum Ratings:

• Max SW voltage: -0.3V to 6V (DC), -1V to 7V (Pulsed <100ns)
• Max voltage, all other pins: -0.3V to 6V
• Max junction temperature: 125 °C
• Storage temperature: -65°C to 150°C

Key Specs:

• Input Start-Up Voltage: 0.25 V (typ, T J = 0°C to 85°C)
• V OUT I Q in Operation: 24 μA (typ, V FB = 1.10V)
• V OUT I Q in Shutdown: 10 μA (typ, SHDN = 0V)
• Peak Current Limit: 0.5 A (typ, V FB = 0.90V, V MPPC = 0.4V)
• Valley Current Limit: 0.35 A (typ, V FB = 0.90V, V MPPC = 0.4V)
• LDO Current Limit: 6 mA (min, V LDO 0.5V Below Regulation Voltage)
• N-Channel On-Resistance: 0.5 Ω (typ, SW to GND)
• P-Channel On-Resistance: 0.5 Ω (typ, SW to V OUT)

Features:

• Low Start-Up Voltage: 250mV
• Maximum Power Point Control
• Wide V IN Range: 225mV to 5V
• Auxiliary 6mA LDO Regulator
• Burst Mode Operation: I Q = 24μA
• Output Disconnect and Inrush Current Limiting
• VIN > V OUT Operation
• Antiringing Control
• Soft Start
• Automatic Power Adjust
• Power Good Indicator

Applications:

• Solar Powered Battery/Supercapacitor Chargers
• Energy Harvesting
• Remote Industrial Sensors
• Low Power Wireless Transmitters
• Cell Phone, MP3, PMP and GPS Accessory Chargers

Package:

• 10-Lead (3mm × 3mm × 0.75mm) Plastic DFN
• 12-Lead Plastic MSOP

• n Low Start-Up Voltage: 250mV
• n Maximum Power Point Control
• n Wide V IN Range: 225mV to 5V
• n Auxiliary 6mA LDO Regulator
• n Burst Mode ® Operation: I Q = 24μA
• n Output Disconnect and Inrush Current Limiting
• n VIN > V OUT Operation
• n Antiringing Control
• n Soft Start
• n Automatic Power Adjust
• n Power Good Indicator
• n 10-Lead 3mm × 3mm × 0.75mm DFN and 12-Lead MSOP Packages

• n Solar Powered Battery/Supercapacitor Chargers
• n Energy Harvesting
• n Remote Industrial Sensors
• n Low Power Wireless T ransmitters
• n Cell Phone, MP3, PMP and GPS Accessory Chargers

LTC3105 Pinout

10-Lead DFN Package (LTC3105EDD)

12-Lead MSOP Package (LTC3105EMS)

Notes

• DFN Package (Pin 11): Exposed pad is GND and must be soldered to PCB for proper thermal performance.
• MSOP Package: Pins 6 and 7 are both GND connections.
• Pin diagrams show two package variants; both are standard LTC3105 configurations with identical pin functions, differing only in package type and thermal characteristics.

The l denotes the specifications which apply over the full operating junction temperature range, otherwise specifications are at T A = 25°C (Note 2). V AUX = V OUT = 3.3V , V LDO = 2.2V , V IN = 0.6V , unless otherwise noted.

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 LTC3105 is tested under pulsed load conditions such that T J ≈ T A . The L TC3105E is guaranteed to meet specifications from 0°C to 85°C junction temperature. Specifications over the -40°C to 85°C operating junction temperature range are assured by design, characterization and correlation with statistical process controls. Note that the maximum ambient temperature consistent with these specifications is determined by specific operating conditions in conjunction with board layout, the rated package thermal impedance and other environmental factors.

Note 3: Current measurements are performed when the LTC3105 is not switching. The current limit values measured in operation will be somewhat higher due to the propagation delay of the comparators.

Note 4: This IC includes over temperature 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 5: The LTC3105 has been optimized for use with high impedance power sources such as photovoltaic cells and thermoelectric generators. The input start-up voltage is measured using an input voltage source with a series resistance of approximately 200mΩ and MPPC enabled. Use of the LTC3105 with lower resistance voltage sources or with MPPC disabled may result in a higher input start-up voltage.

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