Microchip Technology MCP1258T-E/MF

Overview

MCP1258T-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, 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 MCP1258T-E/MF datasheet, MCP1258T-E/MF pinout, MCP1258T-E/MF application, or MCP1258T-E/MF equivalent, key selection criteria include its 10-pin DFN (3 mm × 3 mm) package, active-low BYPASS control, PGOOD open-drain output, thermal shutdown (160°C), and compatibility with ceramic flying capacitors (1 µF each) and low-ESR output capacitors.

Technical Context

The MCP1258T-E/MF uses a switched-capacitor architecture with automatic 1.5x/2x mode selection to maximize efficiency across input voltages (e.g., 84.5% at VIN = 1.8V, IOUT = 10 mA). Its internal 650 kHz oscillator avoids IF-band interference, while soft-start limits inrush current during wake-up (150 µs typical from BYPASS).

BYPASS mode connects VIN directly to VOUT via <1.5 Ω impedance, disabling all internal circuitry except the pass path-reducing quiescent current to 0.25 µA (typical). PGOOD asserts low when VOUT falls below 93% of nominal (7% dropout), with 110 mV hysteresis, and remains high-impedance during BYPASS or shutdown.

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 MCP1258T-E/MS, the MCP1258T-E/MF offers superior thermal performance (57°C/W vs. 200°C/W) in space-constrained layouts; versus TPS60403DBVR, it uniquely enables true zero-IQ biasing via BYPASS-critical for >5-year coin-cell operation.

Availability

MCP1258T-E/MF is available at Aetrix Electronics and suitable for pagers, portable measurement instruments, home automation products, and PIC® MCU bias applications requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.

Supply support for MCP1258T-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, analog, FPGA, and mixed-signal semiconductors, headquartered in Chandler, Arizona.

The MCP1256/7/8/9 product line was designed specifically for low-noise, inductorless DC/DC conversion in battery-powered portable electronics-emphasizing ultra-low quiescent current, small footprint, and robust protection features.

FAQ

What is the function of the BYPASS pin on the MCP1258T-E/MF?

The BYPASS pin on the MCP1258T-E/MF is an active-low input that, when pulled low, connects VIN directly to VOUT through an internal <1.5 Ω switch. This bypasses the charge pump regulation entirely, reducing device quiescent current to 0.25 µA (typical) while maintaining unregulated bias to downstream circuitry-ideal for extending coin-cell life in always-on RTC or MCU standby modes. The MCP1258T-E/MF enters this state immediately upon BYPASS assertion.

Does the MCP1258T-E/MF require external inductors?

No, the MCP1258T-E/MF is an inductorless charge pump DC/DC converter. It uses two 1 µF ceramic flying capacitors (C1 and C2) and input/output ceramic capacitors (CIN, COUT) to generate a regulated 3.3V output. This eliminates magnetic EMI, reduces board area, and simplifies design compared to inductive switchers-making the MCP1258T-E/MF especially suitable for compact, noise-sensitive portable applications.

What is the purpose of the PGOOD pin on the MCP1258T-E/MF?

The PGOOD pin on the MCP1258T-E/MF is an open-drain output that signals regulation status: it remains high-impedance when VOUT is within ±3% of 3.3V, and pulls low when VOUT drops below 93% (≈3.07V) of nominal. This provides system-level power monitoring for safe startup sequencing or fault detection. PGOOD is disabled (high-Z) during BYPASS or shutdown modes, and requires an external pull-up resistor (10 kΩ–1 MΩ to VOUT) for logic-level interfacing.

What is the maximum output current capability of the MCP1258T-E/MF?

The MCP1258T-E/MF delivers up to 100 mA of continuous output current when VIN is ≥2.2V. At lower inputs (1.8V–2.0V), max output current is 30 mA; at 2.0V–2.2V, it is 70 mA. Performance depends on capacitor selection: 1 µF flying caps and 10 µF COUT are required to sustain 100 mA with ≤20 mV_PP ripple. Efficiency ranges from 64% to 84.5%, peaking near VIN = 1.8V and light loads.

How does the MCP1258T-E/MF handle thermal overload?

The MCP1258T-E/MF incorporates thermal shutdown with hysteresis: it disables all internal circuitry when junction temperature exceeds 160°C, then automatically recovers when temperature falls by 15°C (to 145°C). During sustained overload, this causes pulsed output behavior. The 3 mm × 3 mm DFN package has a θ_JA of 57°C/W on a 4-layer board, enabling higher power density than the MSOP variant. Thermal protection operates independently of BYPASS, shutdown, or PGOOD states.