Microchip Technology MCP1253T-33X50I/MS

Overview

MCP1253T-33X50I/MS from Microchip Technology is a low-noise, inductorless, positive-regulated charge pump DC/DC converter supporting selectable 3.3V or 5.0V fixed output, 120 mA output current, 1 MHz switching frequency, ±2.5% output voltage accuracy, and operation from 2.0V to 5.5V input. It serves as a compact, efficient power supply for battery-powered portable electronics requiring buck/boost capability without inductors.

For engineers reviewing the MCP1253T-33X50I/MS datasheet, MCP1253T-33X50I/MS pinout, MCP1253T-33X50I/MS application, or MCP1253T-33X50I/MS equivalent, key selection criteria include its 1 MHz charge pump architecture, dual-voltage selectability via the SELECT pin, PGOOD monitoring, thermal/short-circuit protection, and MSOP-8 packaging optimized for space-constrained designs.

Technical Context

The MCP1253T-33X50I/MS employs a hysteretic (bang-bang) switched-capacitor charge pump with automatic buck/boost mode transition, enabling regulated output when VIN is either below or above VOUT. Its 1 MHz internal oscillator enables use of smaller external capacitors than the 650 kHz MCP1252 variant.

Regulation is achieved by comparing feedback against a 1.21V internal reference; for fixed-output variants, the SELECT pin configures internal resistor dividers to set 3.3V (SELECT = VIN) or 5.0V (SELECT = GND). The open-drain PGOOD pin asserts low when VOUT falls below 93% of nominal, with 4% hysteresis.

Key Specifications

Pinout & Package

Package: 8-Lead Plastic Micro Small Outline Package (MSOP), 3.0 mm × 3.0 mm body, 0.65 mm pitch, exposed pad optional per Microchip drawing.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1252T-33X50I/MS, the MCP1253T-33X50I/MS delivers identical functionality with 1 MHz operation enabling smaller capacitors and lower ripple, while TPS60403DBVR offers footprint reduction at the expense of flexibility, current capability, and monitoring features.

Availability

MCP1253T-33X50I/MS is available at Aetrix Electronics and suitable for white LED backlighting, smart card reader power, GSM SIM interface supply, and flash memory VCC supply requiring stable component supply across industrial temperature ranges.

Supply support for MCP1253T-33X50I/MS 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 microcontrollers, analog, FPGA, and mixed-signal semiconductors headquartered in Chandler, Arizona.

The MCP1253 belongs to Microchip's low-noise, inductorless charge pump DC/DC converter product line, designed specifically for space-constrained, battery-powered portable electronics needing efficient, flexible, and reliable fixed-voltage conversion without magnetics.

FAQ

What output voltages does the MCP1253T-33X50I/MS support, and how is selection implemented?

The MCP1253T-33X50I/MS supports two fixed output voltages: 3.3V and 5.0V. Selection is implemented via the SELECT pin - tie SELECT to VIN for 3.3V output, or to GND for 5.0V output. No external resistors are required, and the internal feedback network ensures ±2.5% accuracy across temperature and load for both configurations. This simplifies design and reduces BOM count compared to adjustable-output alternatives.

How does the MCP1253T-33X50I/MS achieve buck/boost operation without an inductor?

The MCP1253T-33X50I/MS uses a switched-capacitor (charge pump) architecture with a 1 MHz internal oscillator and four-phase charge transfer between VIN, C+, C−, and VOUT. By alternating connection of the flying capacitor (CFLY) between input and output paths, it steps up (boost) when VIN < VOUT or steps down (buck) when VIN > VOUT - all without magnetic components. This enables compact, low-EMI power conversion ideal for portable applications.

What is the purpose and behavior of the PGOOD pin on the MCP1253T-33X50I/MS?

The PGOOD pin on the MCP1253T-33X50I/MS is an open-drain output that signals regulation status: it remains high-impedance when VOUT is within specification, and pulls low when VOUT falls below 93% of nominal (e.g., 2.97V in 3.3V mode). It includes 4% hysteresis and glitch immunity for transients <200 µs. An external pull-up to VOUT is required. During shutdown, PGOOD is high-impedance - enabling system-level power sequencing and fault detection.

What protection features are integrated into the MCP1253T-33X50I/MS?

The MCP1253T-33X50I/MS integrates thermal shutdown (trip at ~160°C, recover at ~145°C), foldback short-circuit protection (limits output to ~200 mA during VOUT-to-GND faults), and soft-start circuitry that limits in-rush current at power-up and wake-up from shutdown. These features ensure robust operation in unattended or harsh environments and prevent damage during abnormal conditions without requiring external protection circuitry.

Can the MCP1253T-33X50I/MS operate from a single-cell Li-ion battery, and what are the minimum input requirements?

Yes, the MCP1253T-33X50I/MS operates from a single-cell Li-ion battery (2.7V–4.2V). For 3.3V output mode (SELECT = VIN), minimum VIN is 2.3V (with reduced output current); for 5.0V output mode (SELECT = GND), minimum VIN is 2.7V. Full 120 mA output is guaranteed at VIN ≥ 2.5V (3.3V mode) or VIN ≥ 3.0V (5.0V mode), making it well-suited for wide-input portable systems without pre-regulation.