Home > Pending > Boost & Inverting DC/DC Converter for CCD Bias Delivers 45mA at 15V & 90mA at -8V from Li-Ion

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Boost & Inverting DC/DC Converter for CCD Bias Delivers 45mA at 15V & 90mA at -8V from Li-Ion

22nd December 2006

ES Admin

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Linear Technology Corporation announces the LT3487, a dual channel (boost/inverter), 2MHz DC/DC converter with output disconnect. Its internal 750mA/900mA 30V switches can deliver up to 45mA at 15V and 90mA at -8V from a single Li-Ion cell, providing bias for the latest generation of CCD (Charge-Coupled Device) imagers. Its input voltage range of 2.3V to 16V enables inputs that range from Li-Ion to multiple cell alkaline/NiMH batteries. Switching at a constant 2MHz, the LT3487 uses tiny low profile capacitors and inductors, generating low noise outputs that are easy to filter. Schottky diodes are integrated into the IC while output voltages can be set with only one resistor per channel, reducing external component count. Packaged in a 3mm x 3mm DFN, the entire solution has less than a 1mm profile and occupies just 50mm2.

The LT3487 offers internal sequencing circuitry that disables the negative channel until the positive channel has reached 87% of its final value. This ensures that the sum of the two outputs is always positive. Intelligent soft-start allows sequential soft-start of the two channels with a single capacitor.

The LT3487EDD is available from stock and pricing starts at $2.30 each for 1,000-piece quantities.

Summary of Features of the LT3487:

· Generates 15V at 45mA, –8V at 90mA from a Li-Ion Cell

· Output Disconnect

· Sequencing: Positive Output Reaches Regulation before Negative Channel Begins Switching

· Internal Schottky Diodes

· 2MHz Constant Switching Frequency

· Requires Only One Resistor per Channel to Set Output Voltages

· VIN Range: 2.3V to 16V

· Output Voltage up to 28V

· Short-Circuit Robust

· Capacitor Programmable Soft-Start

· Separate VBAT Pin Allows Separate Sources for Power & Control Circuitry

· Available in 10-Lead (3mm x 3mm) DFN Package