Microchip Technology MIC94031BM4 TR

Overview

MIC94031BM4 TR from Micrel is a 4-terminal P-channel MOSFET designed for high-side switching in space-constrained systems, featuring 0.75Ω typical R_DS(ON) at V_GS = 4.5V, 13.5V drain-source breakdown voltage, and integrated 500kΩ gate-to-source pull-up resistor. It operates down to 2.7V gate drive and is used in PCMCIA sleep-mode power control and distributed battery management.

For engineers reviewing the MIC94031BM4 TR datasheet, MIC94031BM4 TR pinout, MIC94031BM4 TR application, or MIC94031BM4 TR equivalent, key selection criteria include its SOT-143 package with isolated substrate terminal, low-threshold P-channel operation, internal gate pull-up for reduced external component count, and thermal performance enabled by separate substrate connection.

Technical Context

The MIC94031BM4 TR implements a silicon-gate P-channel enhancement-mode MOSFET architecture with an integrated 500–1000 kΩ gate-to-source pull-up resistor (confirmed for MIC94031 only), enabling single-pin logic-level control without external biasing. Its 4-terminal SOT-143 configuration separates substrate (SS) from source (S), allowing independent thermal and signal referencing.

This structure reduces θ_JA to 220°C/W and supports analog switch functionality-unlike standard 3-terminal MOSFETs-by eliminating body diode conduction path interference and enabling bidirectional blocking when substrate is tied to source.

Key Specifications

Pinout & Package

SOT-143 (M4) package with 1.3mm × 1.3mm footprint and 0.95mm height; includes four terminals: Drain (D), Source (S), Gate (G), and Substrate (SS). The isolated substrate terminal enables thermal optimization and analog switch operation by decoupling bulk semiconductor potential from source node.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar P-channel load switch applications.

Compared with Si1304DL and TPS22965DSGR, the MIC94031BM4 TR uniquely combines ultra-small SOT-143 size, internal gate pull-up, and substrate isolation-enabling both compact high-side switching and analog multiplexing in one device without added components or thermal derating penalties.

Availability

MIC94031BM4 TR is available at Aetrix Electronics and suitable for PCMCIA card power management, distributed battery-powered subsystems, and hand-held scanner load switching requiring stable component supply and long-term industrial availability.

Supply support for MIC94031BM4 TR 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

Micrel, Inc. was a U.S.-based semiconductor company specializing in analog, power management, and timing solutions before its acquisition by Microchip Technology in 2015.

The MIC94030/94031 family was developed as part of Micrel's TinyFET® portfolio to deliver ultra-compact, low-R_DS(ON) P-channel MOSFETs for space- and power-sensitive portable and peripheral applications.

FAQ

What is the function of the substrate (SS) pin on the MIC94031BM4 TR?

The substrate (SS) pin on the MIC94031BM4 TR provides a dedicated connection to the MOSFET's silicon bulk, physically and electrically separated from the source terminal. Per the datasheet, SS must be externally tied to the source (S) node to ensure proper device operation, thermal performance (θ_JA = 220°C/W), and analog switch functionality. This 4-terminal architecture distinguishes MIC94031BM4 TR from standard 3-terminal MOSFETs and enables improved heat dissipation and bidirectional signal blocking.

Does the MIC94031BM4 TR require an external gate pull-up resistor?

No, the MIC94031BM4 TR does not require an external gate pull-up resistor because it integrates a 500–1000 kΩ gate-to-source pull-up internally-confirmed in the Electrical Characteristics table (Note 4) and functional diagram. This feature ensures the device defaults to OFF when the gate is left floating or driven by open-drain logic, reducing bill-of-materials count in microcontroller-based power control circuits using MIC94031BM4 TR.

What is the maximum continuous drain current for the MIC94031BM4 TR at 100°C ambient?

The maximum continuous drain current for the MIC94031BM4 TR is 0.5A at T_A = 100°C, as specified in the Absolute Maximum Ratings table. This derating reflects thermal limitations of the SOT-143 package; at T_A = 25°C, the rating is 1A. Designers must verify PCB copper area and airflow to maintain junction temperature below +150°C under sustained load, especially given MIC94031BM4 TR's 220°C/W θ_JA.

Can the MIC94031BM4 TR be used as an analog switch?

Yes, the MIC94031BM4 TR can be used as an analog switch due to its 4-terminal SOT-143 configuration with isolated substrate (SS) and source (S) terminals. When SS is tied to S, the device supports bidirectional signal blocking with minimal on-resistance distortion-demonstrated in Figure 3 of the datasheet. This capability is unavailable in standard 3-terminal MOSFETs and is a defined design use case for MIC94031BM4 TR in applications like PCMCIA interface multiplexing.

What is the gate threshold voltage range for the MIC94031BM4 TR?

The gate threshold voltage (V_GS(th)) for the MIC94031BM4 TR is specified as 0.6V minimum, 1.0V typical, and 1.4V maximum at V_DS = V_GS and I_D = 250 µA. This low and tightly bounded range ensures consistent turn-on behavior across process, voltage, and temperature variations-making MIC94031BM4 TR compatible with 2.7V–5V logic families without external level-shifting circuitry.