Microchip Technology MCP1259-E/MF

Overview

MCP1259-E/MF from Microchip Technology is a 10-pin DFN-packaged, inductorless 1.5x/2x charge pump DC/DC converter delivering a regulated 3.3V output from 1.8V–3.6V input, supporting up to 100 mA load current with ±3.0% output accuracy and 20 mV_PP ripple at full load - used for biasing PIC® MCUs and real-time clocks in battery-powered home automation and portable instrumentation.

For engineers reviewing the MCP1259-E/MF datasheet, MCP1259-E/MF pinout, MCP1259-E/MF application, or MCP1259-E/MF equivalent, key selection criteria include its BYPASS mode functionality, low 0.25 µA shutdown current, 650 kHz fixed switching frequency, -40°C to +125°C operating range, and compatibility with single lithium coin-cell or dual alkaline/Ni-MH battery supplies.

Technical Context

The MCP1259-E/MF implements an autonomous switched-capacitor topology that dynamically selects between 1.5x and 2x boost modes based on input voltage and load conditions to maximize efficiency - achieving up to 76.7% at 2.8V input and 50 mA output. Its internal 650 kHz oscillator enables compact external filtering without EMI-sensitive inductors.

Unlike MCP1256/7 (SLEEP mode) or MCP1258 (PGOOD), the MCP1259-E/MF integrates a low-battery open-drain output (LBO) with 1.95 V threshold and 240 mV hysteresis, and an active-low BYPASS input enabling direct VIN-to-VOUT connection with 1.5 Ω typical impedance - eliminating quiescent draw while maintaining system bias during ultra-low-power states.

Key Specifications

Pinout & Package

Package: 10-lead 3 mm × 3 mm DFN (exposed pad), RoHS-compliant, thermal resistance θ_JA = 57 °C/W on 4-layer board.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar charge pump DC/DC converter applications.

Compared with MCP1258-E/MF, MCP1259-E/MF trades PGOOD for LBO to support battery telemetry; compared with TPS60403DBVR, it adds BYPASS mode and higher output current but requires more PCB area and two extra control lines.

Availability

MCP1259-E/MF is available at Aetrix Electronics and suitable for home automation sensors, portable measurement instruments, and PIC® MCU bias supplies requiring stable component supply, long-lifecycle assurance, and RoHS-compliant packaging.

Supply support for MCP1259-E/MF includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Microchip Technology is a leading provider of microcontrollers, analog devices, and power management ICs, headquartered in Chandler, Arizona.

The MCP125x family was designed specifically for ultra-low-power, inductorless DC/DC conversion in battery-operated systems - emphasizing minimal external components, wide input range, and integrated power management features like BYPASS and LBO.

FAQ

What is the primary function of the MCP1259-E/MF?

The MCP1259-E/MF is a regulated charge pump DC/DC converter that generates a precise 3.3V output from a 1.8V–3.6V input. Its core function is to provide efficient, inductorless voltage boosting for battery-powered systems. The MCP1259-E/MF uniquely combines BYPASS mode for zero-quiescent-current bias retention and an integrated LBO output for low-battery detection - distinguishing it from other members of the MCP125x family.

How does BYPASS mode operate in the MCP1259-E/MF?

In BYPASS mode, the MCP1259-E/MF electrically connects VIN directly to VOUT via an internal 1.5 Ω switch when the BYPASS pin is driven low. All internal oscillator, charge-pump, and regulation circuitry are disabled, reducing quiescent current to 0.25 µA. This allows external devices like RTCs or memory to remain powered without regulator overhead. The MCP1259-E/MF exits BYPASS automatically upon BYPASS pin release, with 150 µs typical wake-up time to regulated output.

What is the role of the LBO pin on the MCP1259-E/MF?

The LBO (Low-Battery Output) pin on the MCP1259-E/MF is an open-drain output that asserts logic low when the input voltage falls below 1.95 V (typical), with 240 mV hysteresis to prevent chatter. It remains high-impedance during SHDN or BYPASS activation. The MCP1259-E/MF uses this signal to enable firmware-driven battery replacement alerts or graceful shutdown - eliminating need for external voltage comparators in space-constrained designs.

Can the MCP1259-E/MF replace the MCP1256-E/MF in an existing design?

No, the MCP1259-E/MF cannot directly replace the MCP1256-E/MF due to fundamental functional differences: MCP1256-E/MF features PGOOD and SLEEP pins, while MCP1259-E/MF has LBO and BYPASS. Pin functions differ at positions 1 and 2, and internal control logic is incompatible. Replacing MCP1256-E/MF with MCP1259-E/MF would require PCB layout changes, firmware updates for LBO handling, and removal of SLEEP-related code - making it a redesign, not a drop-in swap.

What are the minimum external components required for basic operation of the MCP1259-E/MF?

The MCP1259-E/MF requires four external ceramic capacitors for basic operation: 10 µF input (CIN), 10 µF output (COUT), and two 1 µF flying capacitors (C1, C2). CIN and COUT must be low-ESR types; C1/C2 must be placed symmetrically near their respective pins. No inductors, diodes, or feedback resistors are needed. The MCP1259-E/MF achieves full functionality - including BYPASS and LBO - with only these four passive components and two control signals (BYPASS and SHDN).