Diodes Incorporated MMSTA56-7-F

Overview

MMSTA56-7-F from Diodes Incorporated is a PNP small-signal surface-mount transistor in SOT-323 package, rated for -80 V V_CEO, -500 mA I_C, 200 mW P_D, with h_FE ≥100 at -10 mA/-1.0 V, and f_T = 50 MHz - used in low-power switching and amplification stages of portable audio bias networks and LED driver current sinks.

For engineers reviewing the MMSTA56-7-F datasheet, MMSTA56-7-F pinout, MMSTA56-7-F application, or MMSTA56-7-F equivalent, key selection criteria include V_CEO derating above 25°C, SOT-323 thermal resistance (R_θJA = 625 °C/W), DC gain consistency across -55°C to +150°C, and lead-free RoHS-compliant terminal plating.

Technical Context

This PNP bipolar junction transistor uses epitaxial planar die construction for stable gain and low leakage. It operates with V_CB ≤ -80 V and V_EB ≤ -4.0 V, supporting reliable cutoff under reverse-biased base-emitter conditions typical in level-shifting and high-side switch control.

Its f_T = 50 MHz at V_CE = -1.0 V and I_C = -100 mA enables use in audio-frequency amplifiers and fast-switching logic interfaces. Saturation performance is defined at I_C/I_B = 10, with V_CE(SAT) ≤ -0.25 V and V_BE(SAT) ≤ -1.2 V - critical for low-loss current sinking in battery-powered sensor nodes.

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, lead-free matte tin plating over Alloy 42 leadframe.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP small-signal transistor applications.

Compared with BC807-40-7-F and MMDT5401-7-F, MMSTA56-7-F offers optimal balance of -80 V ruggedness, SOT-323 miniaturization, and production-proven thermal stability - making it preferred for cost-sensitive, space-constrained consumer electronics where voltage margin and footprint are primary constraints.

Availability

MMSTA56-7-F is available at Aetrix Electronics and suitable for portable audio bias networks, LED driver current sinks, and industrial sensor signal conditioning requiring stable component supply, consistent parametric binning, and RoHS-compliant manufacturing traceability.

Supply support for MMSTA56-7-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, headquartered in Plano, Texas, with design centers across Asia and manufacturing in China, Taiwan, and Malaysia.

The MMSTA series belongs to Diodes' small-signal transistor product line, engineered specifically for high-volume, space-constrained applications demanding reliability, thermal robustness, and lead-free compliance - including wearables, IoT sensors, and portable power management.

FAQ

What is the maximum allowable ambient temperature for continuous operation at full rated current?

At I_C = -500 mA, power dissipation reaches 200 mW only if V_CE = -0.4 V. Per Fig. 1, maximum ambient temperature is 150°C only at zero power; at 200 mW, derated ambient limit is approximately 115°C on standard FR-4 per AP02001 layout. Thermal relief pads are recommended above 100 mW.

Is MMSTA56-7-F pin-compatible with MMSTA55-7-F?

Yes - both share identical SOT-323 package and pinout (E-B-C). The only functional difference is V_CEO/V_CBO rating: MMSTA55 is -60 V, MMSTA56 is -80 V. Substitution is electrically safe in -60 V designs, but not vice versa due to breakdown margin.

Does the "Green" molding compound affect electrical performance?

No - the halogen-free green compound (introduced Date Code 0627+) has identical dielectric properties and thermal conductivity to prior formulations. Electrical specs, including leakage (I_CBO ≤ -100 nA) and gain, remain unchanged per DS30167 Rev. 10 test data.

Can MMSTA56-7-F be used in linear amplifier mode with V_CE > 1 V?

Yes - its f_T = 50 MHz and h_FE stability across I_C = 1–100 mA (Fig. 3) support linear operation. However, P_D derating applies: at V_CE = 5 V and I_C = 20 mA, P_D = 100 mW, limiting ambient to ~125°C per Fig. 1. Avoid sustained operation above 150°C junction temperature.