MCP1256T-E/UN

The MCP1256, MCP1257, MCP1258 and MCP1259 are inductorless, positive regulated charge pump DC/DC converters. Generating a regulated 3.3 V output voltage from a 1.8 V to 3.6 V input, they are specifically designed for applications operating from 2 cell alkaline, 2 cell Ni-Cd, 2 cell Ni-MH, or one primary lithium coin cell battery. These devices automatically switch from 1.5x to 2x boost operation modes to maintain high efficiency. In addition, at light output loads, the MCP1256T-E/UN and MCP1257 can be placed in a sleep mode, lowering the quiescent current while maintaining the regulated output voltage. Alternatively, the MCP1258 and MCP1259 provide a bypass feature connecting the input voltage to the output. This allows for real-time clocks, microcontrollers or other system devices to remain biased with virtually no current being consumed by the MCP1258 or MPC1259. In normal operation, the charge pumps switch at a fixed 650 kHz, avoiding sensitive IF bands, and the output voltage ripple is below 20 mVP-P at load currents up to 100 mA. The MCP1256T-E/UN and MCP1258 feature a power-good output that can be used to detect out-of-regulation conditions. The MCP1257 and MCP1259 feature a low battery indication that issues a warning if the input voltage drops below a preset voltage threshold. Extremely low supply current and few external parts (4 capacitors) make these devices ideal for small, battery powered applications. A shutdown mode is also provided for further power reduction. The devices incorporate thermal and short-circuit protection.

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