Microchip Technology MCP1642DT-50I/MS

Overview

MCP1642DT-50I/MS from Microchip Technology is a synchronous step-up DC-DC converter optimized for single-cell battery inputs, delivering fixed 5.0V output with 1.8A peak switch current, 1 MHz PWM operation, and 0.65V typical start-up voltage. It integrates N- and P-channel MOSFETs, internal compensation, power-good monitoring, and true load disconnect (B-version) or input-to-output bypass (D-version) shutdown modes - deployed in portable medical devices, PIC® MCU power supplies, and USB backup chargers.

For engineers reviewing the MCP1642DT-50I/MS datasheet, MCP1642DT-50I/MS pinout, MCP1642DT-50I/MS application, or MCP1642DT-50I/MS equivalent, key selection criteria include low-voltage start-up capability (0.65V @ 3.3V VOUT), fixed 5.0V output accuracy (±3%), 1 µA shutdown current, thermal shutdown at 150°C, and MSOP-8 package compatibility with space-constrained battery-powered designs.

Technical Context

The MCP1642DT-50I/MS implements peak-current-mode PWM control with adaptive slope compensation, operating at a fixed 1 MHz switching frequency (±15%) and supporting discontinuous conduction mode (DCM) with anti-ringing suppression. Its dual-MOSFET synchronous rectifier eliminates external diode losses, while integrated soft-start (550 µs) and inrush limiting prevent output overshoot during low-VIN start-up.

It features a precision 1.21V feedback reference (±3% tolerance), 90% maximum duty cycle, and open-drain Power Good output asserting low when VOUT falls below 90% of regulation. The device supports two distinct shutdown behaviors: true output disconnect (MCP1642B variant) or input-to-output bypass (MCP1642D variant), both consuming ≤1 µA quiescent current.

Key Specifications

Pinout & Package

Package: 8-Lead MSOP (3.0 mm × 4.9 mm, 0.65 mm pitch), with exposed thermal pad (EP) not electrically connected - requires external PCB connection to SGND/PGND plane for thermal performance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous boost regulator applications.

Compared with TPS61200DRCT and ADP5070ARMZ-R7, the MCP1642DT-50I/MS delivers higher peak current (1.8A vs. 1.2A), tighter output accuracy (±3% vs. ±5%), and integrated shutdown modes - simplifying power sequencing in ultra-low-power portable systems without sacrificing 5V delivery capability.

Availability

MCP1642DT-50I/MS is available at Aetrix Electronics and suitable for portable medical sensors, PIC® MCU power supplies, USB emergency backup chargers, wireless sensor nodes, and handheld instrumentation requiring stable component supply and long-term manufacturability.

Supply support for MCP1642DT-50I/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 is a U.S.-based semiconductor manufacturer specializing in microcontrollers, analog, interface, and power management ICs for embedded, industrial, and automotive markets.

The MCP1642B/D family was designed specifically for ultra-low-voltage battery-powered applications - delivering high-efficiency step-up conversion from single-cell alkaline, Li-ion, or NiMH sources with minimal external components.

FAQ

What is the minimum input voltage required for MCP1642DT-50I/MS to start regulating 5.0V output?

The MCP1642DT-50I/MS achieves reliable start-up at 0.9V typical into a 1 mA resistive load for 5.0V output, per DS20005253A-page 3. This is enabled by its low-threshold start-up circuitry and internal bias architecture that transitions from VIN to VOUT sourcing once regulation begins. Operation continues down to 0.5V minimum input voltage at light loads, though output current capability diminishes significantly below 1.8V input.

Does MCP1642DT-50I/MS support true output disconnect during shutdown?

Yes - the "B" suffix in MCP1642DT-50I/MS denotes the True Output Disconnect version. When EN is pulled low, the internal P-channel MOSFET turns off completely, removing the DC path between VIN and VOUT. This prevents reverse current flow and maintains VOUT voltage on the output capacitor, unlike bypass-mode variants. The device draws ≤1 µA from VIN in this state.

What is the purpose of the NC pin (Pin 2) on MCP1642DT-50I/MS?

Pin 2 on the MCP1642DT-50I/MS is Not Connected (NC) - it has no internal bond wire or circuit connection. Per DS20005253A-page 11, this pin must remain unconnected on the PCB. It is not a test pad or thermal relief; routing traces or vias to Pin 2 may cause mechanical stress or unintended coupling and is not recommended.

Can MCP1642DT-50I/MS operate with input voltages higher than 5.0V?

No - the absolute maximum rating for VIN is +6.5V, but the device is specified only for VIN ≤ VOUT (DS20005253A-page 3, Note 2). For the fixed 5.0V version MCP1642DT-50I/MS, operation with VIN > 5.0V violates functional specification and risks unregulated output or instability. Input must remain below 5.0V; for VIN > VOUT applications, a buck or buck-boost topology is required.

How does the Power Good (PG) output behave during startup and fault conditions?

The PG pin on MCP1642DT-50I/MS is an open-drain output that remains high-impedance until VOUT reaches 90% of 5.0V (i.e., 4.5V), then pulls low after a 600 µs delay (PGDELAY). It stays low if VOUT drops below 4.5V and releases after VOUT rises above 4.65V (93% threshold due to 3% hysteresis). During thermal shutdown or undervoltage, PG asserts low within 250 µs (PGRES) to signal loss of regulation.