Diodes Incorporated FMMTL619TC

Overview

FMMTL619 from Diodes Incorporated is a 50V NPN low-saturation transistor in SOT23 package, designed for high-efficiency switching in power control circuits. It delivers 1.25A continuous collector current, 330mV V_CE(sat) at 1.25A/125mA drive, and 160mΩ equivalent on-resistance-enabling compact, low-loss gate driving and DC-DC converter output stages.

For engineers reviewing the FMMTL619 datasheet, FMMTL619 pinout, FMMTL619 application, or FMMTL619 equivalent, key selection criteria include verified AEC-Q101 qualification, thermal resistance (R_θJA = 250°C/W), JEDEC HBM ESD rating (4kV), and complementary PNP pairing with FMMTL720.

Technical Context

This NPN bipolar junction transistor operates as a saturated switch in medium-power linear and switching applications. Its BV_CEO = 50V and I_C = 1.25A rating support use in 24V–48V industrial power rails, while f_T = 180MHz enables fast turn-on (t_on = 182ns) and turn-off (t_off = 379ns) under pulsed conditions.

The device uses a planar epitaxial structure with matte tin-plated leads and green molding compound (UL 94V-0). Thermal performance is characterized for 15mm × 15mm 1oz copper PCB mounting, with R_θJL = 197°C/W confirming efficient heat transfer from junction to lead solder point.

Key Specifications

Pinout & Package

SOT23 surface-mount package: 3-pin, single-ended, plastic-molded case with UL 94V-0 flammability rating and moisture sensitivity level 1 (J-STD-020).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN low-saturation transistor applications.

Compared with ZXTN2012ZTA and DMT3006LPSQ-13, FMMTL619 offers optimal balance of SOT23 compactness, AEC-Q101 compliance, and verified 50V/1.25A switching capability-making it preferred for space-constrained automotive and industrial control nodes where BJT simplicity and thermal predictability matter.

Availability

FMMTL619 is available at Aetrix Electronics and suitable for MOSFET gate driving, DC-DC converter switching, and LED constant-current regulation requiring stable component supply across automotive production, industrial automation, and embedded power management programs.

Supply support for FMMTL619 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, manufacturing, and sales operations across Asia, Europe, and North America.

The FMMTL619 belongs to Diodes' AEC-Q101-qualified low-saturation transistor product line, engineered specifically for high-reliability power switching in automotive body electronics, lighting, and power conversion subsystems.

FAQ

What is the maximum safe operating temperature for FMMTL619?

The FMMTL619 has an operating junction temperature range of −55°C to +150°C, qualified per AEC-Q101. At ambient temperatures above +85°C, derating is required: maximum power dissipation drops linearly from 500mW at +25°C to zero at +150°C, based on R_θJA = 250°C/W for standard PCB layout.

Is FMMTL619 pin-compatible with other SOT23 NPN transistors?

FMMTL619 uses standard SOT23 pinout (Emitter-Base-Collector on pins 1-2-3), matching industry convention. However, electrical parameters-including h_FE profile, V_CE(sat), and f_T-differ significantly from generic SOT23 NPNs like MMBT3904; direct substitution requires validation of saturation drive current and thermal limits.

Does FMMTL619 require a base resistor in typical switching applications?

Yes. To achieve full saturation at I_C = 1.25A, the base must be driven with ≥125mA. A series base resistor is mandatory when using voltage-mode drivers (e.g., MCU GPIO); its value is calculated as R_B = (V_DRIVE − V_BE(sat)) / 125mA, where V_BE(sat) = 1.02V typical at 1.25A.

How does the 160mΩ R_CE(SAT) specification relate to actual circuit performance?

R_CE(SAT) = 160mΩ is derived from V_CE(sat)/I_C at rated conditions (330mV ÷ 1.25A), representing the effective on-resistance for loss calculation. It enables accurate prediction of conduction loss (P_LOSS = I_C² × 0.16Ω) and thermal rise in PCB-mounted designs, supporting thermal margin analysis without iterative testing.