Microchip Technology MCP1642D-18I/MS

Overview

MCP1642D-18I/MS from Microchip Technology is a synchronous step-up DC-DC converter with fixed 1.8V output, designed for ultra-low-voltage battery-powered systems. It starts up from 0.65V input (typical), delivers >175 mA at 1.2V_IN/1.8V_OUT, operates at 1 MHz PWM, and features input-to-output bypass shutdown mode. Used in single-cell alkaline/Li-ion portable medical sensors and PIC MCU power rails.

For engineers reviewing the MCP1642D-18I/MS datasheet, MCP1642D-18I/MS pinout, MCP1642D-18I/MS application, or MCP1642D-18I/MS equivalent, key selection criteria include low-startup-voltage capability, 1.8V fixed output accuracy (±3%), 1 µA shutdown current, and MSOP-8 package compatibility with space-constrained handheld instruments.

Technical Context

The MCP1642D-18I/MS implements peak-current-mode PWM control with adaptive slope compensation and an integrated 1.8A N-channel boost switch + synchronous P-channel rectifier. Its 1 MHz fixed-frequency operation enables compact magnetics, while anti-ringing control suppresses high-frequency noise at the SW node.

Unlike conventional boost regulators, it supports true input-to-output bypass during shutdown-connecting VIN directly to VOUT via the internal P-MOSFET-enabling load operation without converter switching when input voltage suffices. Start-up bias transitions from VIN to VOUT once regulation is achieved, sustaining operation down to 0.35V input at light loads.

Key Specifications

Pinout & Package

Package: 8-Lead MSOP (3.0 mm × 4.9 mm, 0.65 mm pitch), exposed thermal pad not electrically connected - requires PCB thermal pad 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 ADP5070ACPZ-R7, the MCP1642D-18I/MS uniquely combines factory-trimmed 1.8V output, 1 µA shutdown, and input-to-output bypass in an 8-pin MSOP - delivering lowest system-level cost and smallest solution size for fixed-rail battery-powered designs.

Availability

MCP1642D-18I/MS is available at Aetrix Electronics and suitable for portable medical devices, PIC MCU power supplies, handheld diagnostic tools, and wireless industrial transmitters requiring stable component supply and long-term production continuity.

Supply support for MCP1642D-18I/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, and power management ICs for embedded control applications.

The MCP1642B/D family was designed specifically for ultra-low-voltage battery-powered systems - enabling reliable operation from single-cell alkaline, Li-ion, and NiMH sources in space-constrained portable electronics.

FAQ

What is the minimum input voltage required for the MCP1642D-18I/MS to start regulating 1.8V output?

The MCP1642D-18I/MS starts regulation from 0.65V typical input voltage with a 1 mA resistive load. This is verified per DS20005253A-page 3, Table 1-1, Note 1. Below this threshold, the device remains inactive; above it, the internal start-up logic engages the P-channel rectifier to charge the output capacitor before initiating PWM switching. The MCP1642D-18I/MS sustains regulation down to 0.35V input under light loads after start-up.

Does the MCP1642D-18I/MS require external feedback resistors to set its 1.8V output?

No. The MCP1642D-18I/MS uses an internal factory-trimmed resistor divider to fix the output at 1.8V - pin 2 (VFB) is NC and must remain unconnected. This eliminates external resistor tolerances and leakage effects, ensuring ±3% output accuracy over temperature and line/load conditions as specified in DS20005253A-page 3. The MCP1642D-18I/MS achieves this without any external components on the feedback path.

How does the input-to-output bypass mode function in the MCP1642D-18I/MS during shutdown?

When EN is pulled low, the MCP1642D-18I/MS activates its internal P-channel MOSFET to connect VIN directly to VOUT - providing a low-resistance path (<1 Ω typical) that sustains load power without switching losses. This differs from true disconnect (MCP1642B) and enables continued operation of low-power loads (e.g., MCU sleep mode) when VIN ≥ 1.8V. The MCP1642D-18I/MS draws <1 µA total input current in this state.

What is the maximum continuous output current the MCP1642D-18I/MS can deliver at 1.8V output?

The MCP1642D-18I/MS delivers >175 mA continuously at 1.2V input and 1.8V output, as confirmed in DS20005253A-page 1, Features section. At higher input voltages (e.g., 2.4V), output current increases - reaching >300 mA at 1.5V input. Performance is limited by the 1.8A peak switch current and thermal dissipation in the MSOP-8 package; derating is required above +65°C ambient.

Is the PG (Power Good) pin of the MCP1642D-18I/MS compatible with 3.3V logic microcontrollers?

Yes. The PG pin is an open-drain output with 0.4V max low-level voltage at 5 mA sink current (DS20005253A-page 5). When pulled up to 3.3V, it provides clean active-low signaling to standard CMOS inputs. The threshold is set at 90% of nominal VOUT (1.62V for 1.8V output), with 3% hysteresis - ensuring robust detection of regulation loss. The MCP1642D-18I/MS PG response time is 250 µs, suitable for real-time fault monitoring.