onsemi MPSA13_D74Z

Overview

MPSA13_D74Z from ON Semiconductor (formerly Fairchild) is an NPN Darlington transistor optimized for high-current-switching applications with DC current gain up to 10,000 at IC = 100 mA, VCE = 5.0 V, and VCE(sat) = 1.5 V at IC = 100 mA / IB = 0.1 mA. It supports continuous collector current of 1.2 A and operates across –55°C to +150°C junction temperature range, commonly used in relay drivers, lamp drivers, and low-frequency power switching circuits.

For engineers reviewing the MPSA13_D74Z datasheet, pinout, applications, or equivalent options, key selection considerations include its Darlington architecture for ultra-high hFE, TO-92 package thermal limits (RθJA = 200°C/W), saturation voltage trade-off versus single-stage transistors, and suitability for DC-coupled switching where base drive current is constrained.

Technical Context

The MPSA13_D74Z integrates two cascaded NPN transistors in a monolithic Darlington configuration, delivering hFE ≥ 5,000 (min) at IC = 10 mA and ≥ 10,000 (min) at IC = 100 mA. Its V(BR)CES = 30 V and IC = 1.2 A rating enable robust operation in medium-power linear and switching roles without external gain staging.

Thermal design is constrained by RθJA = 200°C/W on FR-4 PCB (1.6" × 1.6"), limiting practical continuous power dissipation to 625 mW at 25°C ambient with 5.0 mW/°C derating above that. VBE(on) = 2.0 V at IC = 100 mA reflects the stacked base-emitter junction drop inherent to Darlington topology.

Key Specifications

Pinout & Package

Package: TO-92 - through-hole plastic package with 3.60 mm lead spacing, 14.47 mm body length, and standardized mounting footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ULN2003A and MPSA14, the MPSA13_D74Z delivers the highest guaranteed hFE in a single-device TO-92 package, making it optimal for space-constrained, ultra-low-base-drive applications where discrete Darlington performance is prioritized over integration or multi-channel capability.

Availability

MPSA13_D74Z is available at Aetrix Electronics and suitable for relay driver circuits, lamp/LED array control, DC motor starter stages, and industrial sensor interface outputs requiring stable component supply and long-term manufacturability.

Supply support for MPSA13_D74Z 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

ON Semiconductor is a global semiconductor supplier focused on energy-efficient electronics, delivering power management, analog, sensor, and discrete solutions for automotive, industrial, and cloud infrastructure markets.

The MPSA13_D74Z belongs to ON Semiconductor's legacy general-purpose bipolar transistor family, designed specifically for cost-sensitive, high-gain DC switching applications where simplicity, reliability, and TO-92 compatibility are essential.

FAQ

What is the maximum continuous collector current rating for MPSA13_D74Z?

The MPSA13_D74Z is rated for 1.2 A continuous collector current at Ta = 25°C with appropriate PCB copper area. Derating is required above 25°C ambient per the 5.0 mW/°C specification, and actual usable current depends on thermal management. The MPSA13_D74Z must not exceed its 625 mW total device dissipation limit under sustained operation.

Does MPSA13_D74Z have built-in protection features like flyback diodes?

No, the MPSA13_D74Z is a bare Darlington transistor without integrated protection components. External flyback diodes are required when switching inductive loads such as relays or solenoids to prevent voltage spikes exceeding V(BR)CES = 30 V. This design choice maintains flexibility for custom snubber networks and avoids fixed clamping thresholds. The MPSA13_D74Z relies on external circuitry for robustness.

Can MPSA13_D74Z replace a standard NPN transistor like 2N2222 in the same circuit?

No - the MPSA13_D74Z cannot be directly substituted for a 2N2222 without circuit revision. Its Darlington structure yields VBE(on) ≈ 2.0 V and VCE(sat) ≈ 1.5 V, significantly higher than the 2N2222's ~0.7 V and ~0.2 V, respectively. Base resistor values must be increased to accommodate higher VBE, and load voltage margins must account for elevated saturation drop. The MPSA13_D74Z serves different design goals: ultra-high gain, not low VCE(sat).

What is the thermal resistance from junction to ambient (RθJA) for MPSA13_D74Z?

The MPSA13_D74Z has a specified RθJA of 200°C/W when mounted on a standard FR-4 PCB measuring 1.6" × 1.6" × 0.06". This value assumes no added copper pour or heatsinking. In practice, adding thermal relief pads or local copper planes can improve this figure. For reliable operation, junction temperature must remain ≤ +150°C, so ambient temperature and power dissipation must be jointly evaluated using RθJA. The MPSA13_D74Z thermal performance is defined under these standardized test conditions.

Is MPSA13_D74Z suitable for high-frequency switching applications?

No - the MPSA13_D74Z is not intended for high-frequency switching. Its fT (current gain bandwidth product) is not characterized in the datasheet, and Darlington architecture inherently limits switching speed due to charge storage in two cascaded junctions. Typical turn-on/turn-off times are in the microsecond range. Use the MPSA13_D74Z only in DC or low-frequency (<10 kHz) applications such as relay control, lamp dimming, or motor start/stop sequencing.