Microchip Technology MCP1258-E/MF

Overview

MCP1258-E/MF from Microchip Technology is an inductorless, positive regulated charge pump DC/DC converter delivering a fixed 3.3V output from 1.8V–3.6V input. It supports up to 100 mA output current at VIN ≥ 2.2V, features ±3.0% output voltage accuracy, 20 mV_PP ripple at full load, and integrated BYPASS mode for direct VIN-to-VOUT connection-enabling ultra-low-power biasing of real-time clocks and microcontrollers in coin-cell-powered systems.

For engineers reviewing the MCP1258-E/MF datasheet, MCP1258-E/MF pinout, MCP1258-E/MF application, or MCP1258-E/MF equivalent, key selection considerations include its 10-pin DFN (3 mm × 3 mm) package, active-low BYPASS control, PGOOD open-drain output with 93% V_OUT threshold, thermal shutdown at 160°C, and compatibility with ceramic flying capacitors (C1/C2 = 1 µF).

Technical Context

The MCP1258-E/MF operates as a switched-capacitor charge pump with automatic 1.5x/2x mode selection based on input voltage and load conditions. Its internal 650 kHz oscillator drives synchronous switching of four external flying capacitors (C1±, C2±) to regulate V_OUT without inductors.

BYPASS mode connects VIN directly to VOUT via a 1.5 Ω typical impedance path while disabling all internal circuitry-including oscillator, regulation, and protection-reducing quiescent current to 0.25 µA (typ). PGOOD asserts low when V_OUT falls below 93% of nominal, with 110 mV hysteresis and glitch immunity for transient rejection.

Key Specifications

Pinout & Package

Package: 10-lead 3 mm × 3 mm DFN (exposed pad), RoHS-compliant, moisture sensitivity level 3.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1259-E/MF, MCP1258-E/MF provides system-level power sequencing via PGOOD instead of battery monitoring; compared with TPS60403DBVR, it delivers 67% higher output current and enables zero-quiescent biasing through BYPASS-critical for multi-year coin-cell operation.

Availability

MCP1258-E/MF is available at Aetrix Electronics and suitable for real-time clock biasing, low-power microcontroller supply, home automation sensor nodes, and pager power management requiring stable component supply across extended product lifecycles.

Supply support for MCP1258-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 Inc. is a leading provider of microcontroller, mixed-signal, analog, and Flash-IP solutions, serving automotive, industrial, consumer, and communications markets with high-reliability silicon and development tools.

The MCP125x family is designed specifically for compact, battery-powered applications needing inductorless step-up conversion-targeting portable instrumentation, wearables, and energy-harvesting systems where EMI and board space are critical constraints.

FAQ

What is the function of the BYPASS pin on the MCP1258-E/MF?

The BYPASS pin on the MCP1258-E/MF is an active-low control that, when pulled low, connects VIN directly to VOUT through an internal 1.5 Ω switch while disabling all internal circuitry-including the oscillator, regulation loop, and protection features. This allows the MCP1258-E/MF to deliver unregulated battery voltage to downstream devices like RTCs with sub-microamp quiescent current, extending coin-cell life significantly. The MCP1258-E/MF remains fully functional after BYPASS release, with 150 µs typical wake-up time to regulated 3.3V.

Does the MCP1258-E/MF require external inductors?

No, the MCP1258-E/MF does not require external inductors. It uses a switched-capacitor charge pump architecture with four external ceramic flying capacitors (C1±, C2±, each 1 µF) to generate its regulated 3.3V output. This eliminates magnetic EMI, reduces solution size, and simplifies layout-making the MCP1258-E/MF ideal for space-constrained, noise-sensitive portable applications such as pagers and handheld instruments.

How does the PGOOD output behave during BYPASS mode on the MCP1258-E/MF?

During BYPASS mode, the PGOOD output on the MCP1258-E/MF is placed in a high-impedance state and does not reflect VOUT status. This behavior is explicitly defined in the datasheet: "PGOOD is high impedance when SHDN is low or when BYPASS is low (MCP1258)." Therefore, PGOOD cannot be used for power-good monitoring while BYPASS is active. System designers must rely on other signals-or exit BYPASS before checking PGOOD-for regulated output validation.

What is the maximum output current capability of the MCP1258-E/MF across its input voltage range?

The MCP1258-E/MF delivers up to 100 mA output current when VIN is ≥2.2V, 70 mA at 2.0V–2.2V, and 30 mA at 1.8V–2.0V. These values are specified in the DC CHARACTERISTICS table (DS21989B-page 3) and reflect actual tested performance-not theoretical limits. At VIN = 2.4V and IOUT = 100 mA, efficiency remains ≥67.5%, confirming stable operation under full load. The device sustains this current with ≤20 mVPP ripple when using 10 µF COUT and proper PCB layout.

Can the MCP1258-E/MF operate over the full industrial temperature range?

Yes, the MCP1258-E/MF is fully characterized and guaranteed to operate across the junction temperature range of –40°C to +125°C. This specification is confirmed in the "Temperature Ranges" table (DS21989B-page 5) and supported by thermal resistance data: θJA = 57°C/W for the DFN package on a 4-layer board. The device incorporates thermal shutdown at 160°C with 15°C hysteresis, ensuring robustness in sealed enclosures or high-ambient environments typical of industrial automation and automotive cabin applications.