Diodes Incorporated MMSTA13-7-F

Overview

MMSTA13-7-F from Diodes Incorporated is an NPN surface-mount Darlington transistor in SOT-323 package, rated for 30 V V_CEO, 300 mA I_C, and 200 mW P_D, with minimum h_FE of 5,000 at 10 mA/5 V - optimized for low-power switching and amplification in space-constrained signal routing and sensor interface circuits.

For engineers reviewing the MMSTA13-7-F datasheet, MMSTA13-7-F pinout, MMSTA13-7-F application, or MMSTA13-7-F equivalent, this part supports precise low-current gain control, ultra-low base drive requirements, and thermal-stable operation across -55°C to +150°C ambient environments in portable and industrial electronics.

Technical Context

This Darlington pair integrates two NPN transistors monolithically to deliver high DC current gain (h_FE ≥ 5,000) with minimal base current - enabling direct drive from microcontroller GPIOs without external level-shifting. Its V_CE(SAT) ≤ 1.5 V at I_C = 100 mA / I_B = 100 μA ensures efficient low-voltage switching.

The device uses epitaxial planar die construction and green molding compound compliant with UL 94V-0, supporting lead-free reflow assembly. Thermal resistance R_θJA = 625 °C/W reflects its SOT-323 footprint's inherent power limitation, requiring careful PCB copper area management for sustained 200 mW operation.

Key Specifications

Pinout & Package

Package: SOT-323 - ultra-small surface-mount plastic case (2.0–2.2 mm × 1.15–1.35 mm × 0.25–0.40 mm height), UL 94V-0 rated, moisture sensitivity Level 1, matte tin-plated Alloy 42 leads.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Darlington transistor applications.

Compared with MMBT13-7-F and ZTX1048A, MMSTA13-7-F uniquely delivers Darlington-level gain in SOT-323, making it optimal for space-constrained, ultra-low-drive digital switching - whereas alternatives trade gain for speed or power handling.

Availability

MMSTA13-7-F is available at Aetrix Electronics and suitable for LED driver circuits, microcontroller GPIO expansion, low-power relay control, and thermal sensor interfaces requiring stable component supply and RoHS-compliant sourcing.

Supply support for MMSTA13-7-F 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, specializing in high-reliability, energy-efficient components for consumer, industrial, and automotive markets.

The MMSTA series belongs to Diodes' general-purpose bipolar transistor product line, designed specifically for compact, low-power switching and amplification in portable and space-sensitive electronics.

FAQ

What is the maximum allowable base current for MMSTA13-7-F?

The datasheet does not specify an absolute maximum base current rating. However, design practice limits I_B to ≤10% of I_C to avoid excessive power dissipation in the base-emitter junction. At I_C = 300 mA, I_B should remain ≤30 mA - though typical operation uses 10–100 μA due to high h_FE.

Can MMSTA13-7-F replace a standard NPN transistor like 2N3904 in existing designs?

No - MMSTA13-7-F is a Darlington pair with much higher h_FE and V_BE(SAT) ≈ 2.0 V, versus 2N3904's ~100 h_FE and 0.65–0.85 V V_BE. Direct substitution would cause incorrect biasing, excessive base voltage drop, and potential failure to saturate in common-emitter configurations.

Is MMSTA13-7-F suitable for linear amplification applications?

It can operate in the active region, but its Darlington structure introduces nonlinearities and wide h_FE variation (5,000–10,000) across current and temperature. For precision linear amplification, purpose-built small-signal transistors (e.g., BC847) or op-amps are preferred; MMSTA13-7-F is optimized for switching.

Does MMSTA13-7-F require a heatsink in standard SOT-323 mounting?

No - the SOT-323 package has no provision for heatsinking. At 200 mW P_D and R_θJA = 625 °C/W, junction temperature rise is ~125°C above ambient at full power. For reliable operation, keep I_C ≤ 100 mA continuous or use PCB copper pour as thermal relief; heatsinks are physically incompatible.