Diodes Incorporated MMSTA92-7

Overview

MMSTA92-7 from Diodes Incorporated is a PNP small-signal surface-mount transistor in SOT-323 package, rated for V_CEO = −300 V, I_C = −100 mA, and P_D = 200 mW, with h_FE = 25–40 at I_C = −1.0 mA and V_CE = −10 V; used in high-voltage low-power switching and amplification circuits such as CRT deflection drivers and relay interface stages.

For engineers reviewing the MMSTA92-7 datasheet, MMSTA92-7 pinout, MMSTA92-7 application, or MMSTA92-7 equivalent, key selection criteria include breakdown voltage margin, saturation voltage at target drive current, thermal resistance under PCB layout constraints, and compatibility with complementary NPN MMSTA42 in push-pull configurations.

Technical Context

This PNP bipolar junction transistor employs epitaxial planar die construction for stable high-voltage operation and low leakage. Its −300 V V_CEO and −300 V V_CBO ratings support use in flyback snubbers and HV bias rails where collector-to-emitter reverse blocking is critical.

The device delivers V_CE(SAT) ≤ −0.5 V at I_C = −20 mA / I_B = −2.0 mA and f_T = 50 MHz at V_CE = −20 V / I_C = −10 mA, enabling reliable switching up to ~100 kHz and modest RF amplification in low-current signal paths.

Key Specifications

Pinout & Package

Package: SOT-323 (3-pin, plastic molded, RoHS-compliant, moisture sensitivity level 1). Dimensions per Diodes Inc. DS30174 Rev. 9: length 2.00–2.20 mm, width 1.15–1.35 mm, height 0.25–0.40 mm.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP high-voltage switching applications.

Compared with MMSTA92-7, MMSTA42-7 offers identical mechanical and thermal behavior with inverted polarity for complementary designs, while BC807-25-7-F trades high-voltage capability for higher DC gain and lower saturation voltage in sub-50 V systems.

Availability

MMSTA92-7 is available at Aetrix Electronics and suitable for CRT deflection drivers, relay interface circuits, high-voltage bias supplies, and low-power audio preamps requiring stable component supply and long-lifecycle availability.

Supply support for MMSTA92-7 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, Malaysia, and Taiwan.

The MMSTA92 belongs to Diodes' high-voltage small-signal transistor product line, engineered specifically for legacy display, industrial control, and test equipment applications demanding robust breakdown performance in miniature packages.

FAQ

What is the maximum safe operating voltage for MMSTA92-7 in continuous DC mode?

The absolute maximum collector-emitter voltage (V_CEO) is −300 V at T_A = 25°C. Derating is required above 25°C ambient: R_θJA = 625°C/W implies junction temperature rises ~125°C at full 200 mW dissipation, so sustained operation above −250 V is recommended only with heatsinking or forced air cooling.

Can MMSTA92-7 be used as a direct replacement for BCW68G in a 200 V flyback snubber?

No. BCW68G has V_CEO = −120 V and is unsuitable for 200 V applications. MMSTA92-7's −300 V rating makes it viable, but its lower h_FE (25–40 vs. BCW68G's 100–250) requires increased base drive current-verify I_B ≥ 2× original design to ensure saturation under load.

Does MMSTA92-7 require special PCB layout considerations for thermal performance?

Yes. With R_θJA = 625°C/W on standard FR-4, thermal relief pads and copper pour under the SOT-323 footprint are essential. Diodes Inc. AP02001 recommends ≥10 mm² of 1-oz copper connected to emitter pad; avoid narrow traces on collector/base pins to prevent localized heating during pulsed operation.

Is the "K3R" marking on MMSTA92-7-7 devices traceable to date code and lot?

Yes. "K3R" is the product type code per DS30174; the adjacent two-character YM code denotes year/month (e.g., "N9" = September 2002). Full traceability-including wafer lot, assembly site, and test data-is maintained by Diodes Incorporated for all MMSTA92-7-F shipments and available upon request with valid batch ID.