LTC3105

Part: LTC3105 (LTC3105EDD, LTC3105EMS) — Linear Technology

Type: Step-Up (Boost) DC/DC Converter with Maximum Power Point Control

Description: 400 mA synchronous step-up converter with 225 mV to 5 V input range, 250 mV start-up, integrated maximum power point control, 6 mA auxiliary LDO and 24 μA quiescent current.

Operating Conditions:

• Input operating voltage: 0.225–5 V
• Operating junction temperature: -40 to 85 °C (specifications guaranteed 0 to 85 °C; -40 to 85 °C assured by design and characterization)
• Output voltage adjust range: 1.6–5.25 V
• LDO output adjust range: 1.4–5 V

Absolute Maximum Ratings:

• SW voltage: -0.3 V to 6 V DC; -1 V to 7 V pulsed (<100 ns)
• All other pins: -0.3 V to 6 V
• Maximum junction temperature: 125 °C
• Storage temperature: -65 to 150 °C
• Lead temperature (soldering, 10 s, MS package): 300 °C

Key Specs:

• Input start-up voltage: 0.25 V typ, 0.4 V max (0.36 V max for TJ = 0 to 85 °C), with ~200 mΩ source resistance and MPPC enabled
• Feedback voltage (FB): 0.984 / 1.004 / 1.024 V (min/typ/max)
• VOUT quiescent current: 24 μA in operation (VFB = 1.10 V), 10 μA in shutdown
• MPPC pin output current: 10 μA typ (9.72–10.28 μA) at VMPPC = 0.6 V
• Switch on-resistance: 0.5 Ω typ for both N-channel and P-channel
• Peak current limit: 0.4 A min, 0.5 A typ; valley current limit: 0.275 A min, 0.35 A typ
• LDO output voltage: 2.2 V typ (2.148–2.236 V) with FBLDO = 0 V; current limit 6 mA min, 12 mA typ
• LDO dropout: 105 mV typ at 6 mA; load regulation 0.40% typ (1–6 mA)
• PGOOD threshold: 90% typ of feedback voltage (85–95%), VOUT falling

Features:

• Low start-up voltage of 250 mV
• Maximum power point control with user-programmable set point
• Auxiliary 6 mA LDO regulator
• Burst Mode operation with IQ = 24 μA
• Output disconnect and inrush current limiting
• VIN > VOUT operation
• Antiringing control
• Soft start
• Automatic power adjust
• Power good indicator
• Thermal shutdown

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 3 mm × 3 mm × 0.75 mm DFN (LTC3105EDD)
• 12-lead MSOP (LTC3105EMS)

• 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

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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