onsemi MPSA29

Overview

MPSA29 from onsemi is an NPN silicon Darlington transistor in a TO-92 package, rated for 100 V_CEO, 500 mA continuous collector current, and 1.5 W power dissipation at T_C = 25°C. It delivers high DC current gain (h_FE ≥ 10,000 at I_C = 10 mA), low saturation voltage (V_CE(sat) ≤ 1.5 V), and 200 MHz f_T, making it suitable for high-gain switching and linear amplification in industrial control interfaces.

For engineers reviewing the MPSA29 datasheet, pinout, applications, or equivalent options, key selection criteria include its 100 V C-E breakdown rating, Darlington architecture enabling microampere-level base drive, thermal resistance of 83.3°C/W (junction-to-case), and Pb-free TO-92 packaging compliant with RoHS and J-STD-020 reflow profiles.

Technical Context

The MPSA29 integrates two cascaded NPN transistors in a monolithic Darlington configuration, delivering ultra-high current gain without external biasing networks. Its V_(BR)CES = 100 V and V_(BR)CBO = 100 V support operation in medium-voltage switching rails up to 80 V DC with margin.

Designed for linear and saturated-mode operation, the device exhibits V_CE(sat) = 0.7–1.5 V across I_C = 10–100 mA and I_B/I_C = 0.001–0.001, with f_T = 125–200 MHz confirming usable bandwidth beyond audio frequencies into low RF ranges.

Key Specifications

Pinout & Package

Package: TO-92 (Case 29-11), straight-lead or bent-lead variants, Pb-free (G suffix), 2000 units per ammo pack (MPSA29RLRPG).

Key Features

Applications

Equivalent & Alternatives

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

Compared with ULN2003A and BC817-40, the MPSA29 uniquely balances ultra-high gain, 100 V rating, and TO-92 usability-making it optimal for single-load, high-isolation, low-drive applications where array integration or miniature packaging is unnecessary.

Availability

MPSA29 is available at Aetrix Electronics and suitable for industrial relay drivers, linear audio preamplifiers, LED array controllers, thermal cut-off circuits, and analog sensor interface modules requiring stable component supply and long-term obsolescence management.

Supply support for MPSA29 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

onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The MPSA29 belongs to onsemi's Preferred Devices family of general-purpose bipolar transistors, engineered for reliability, manufacturability, and broad compatibility in legacy and new-design industrial control hardware.

FAQ

What is the maximum safe operating voltage for MPSA29 in switching applications?

The MPSA29 has a guaranteed minimum collector-emitter breakdown voltage V_(BR)CES of 100 V under test conditions (I_C = 100 mA, V_BE = 0). For reliable switching operation, design voltage stress to ≤80 V DC to maintain 20% margin against transients and temperature derating. The MPSA29 datasheet specifies this rating applies across the full –55°C to +150°C junction temperature range.

Does MPSA29 require a base resistor, and what value is recommended?

Yes, the MPSA29 requires an external base resistor to limit base current and prevent thermal runaway. For I_C = 100 mA and h_FE ≥ 10,000, a 47 kΩ resistor from a 5 V MCU GPIO yields ~100 µA I_B, ensuring saturation while keeping power dissipation below 0.25 mW. The MPSA29's Darlington structure makes it especially sensitive to uncontrolled base current, so precise resistor selection is critical.

Can MPSA29 be used in linear amplification mode, and what is its typical small-signal gain?

Yes, the MPSA29 is characterized for linear operation with h_FE ≥ 10,000 at I_C = 10 mA and V_CE = 5 V, and f_T = 200 MHz confirms usable bandwidth. Its low noise figure and stable gain make it suitable for low-level signal amplification. When biased correctly, the MPSA29 achieves >60 dB voltage gain in common-emitter configurations without oscillation, as verified in onsemi's Figure 6 (high-frequency current gain).

Is MPSA29RLRPG RoHS-compliant and lead-free?

Yes, MPSA29RLRPG is explicitly marked as Pb-free in the onsemi datasheet and shipping documentation. The "G" suffix denotes compliance with RoHS Directive 2011/65/EU and JEDEC J-STD-020D reflow profile requirements. The TO-92 package uses matte tin plating over copper leads, with no lead content detected above 1000 ppm threshold limits.

How does MPSA29 compare to MPSA28 in terms of voltage rating and interchangeability?

The MPSA29 has V_(BR)CES = 100 V and V_(BR)CBO = 100 V, while the MPSA28 is rated at 80 V for both parameters. They share identical pinout, package, gain, and saturation characteristics-but the MPSA29 is not a drop-in replacement in 80–100 V applications unless circuit analysis confirms transient margins. The MPSA29 datasheet states it is a Preferred Device, indicating enhanced process control and extended voltage capability over the MPSA28.