TL431AILPG Replacement: TL431BCLP, TL1431IZ

Original Part

TL431AILPG

onsemi

Shunt Voltage Reference IC Adjustable 2.495V 36 VV ±1% 100 mA TO-92 (TO-226)

Alternative Part

TL431BCLP

onsemi

Shunt Voltage Reference IC Adjustable 2.495V 36 VV ±0.4% 100 mA TO-92-3

TL1431IZ

STMicroelectronics

Shunt Voltage Reference IC Adjustable 2.5V 36 VV ±0.4% 100 mA TO-92-3

1. TL431BCLP Substitution Conclusion The TL431BCLP can serve as a full functional replacement for the original TL431AILPG. Both devices are from the same manufacturer (onsemi) and share identical core electrical parameters: output voltage range (2.495V-36V), maximum cathode current (100mA), and typical temperature coefficient (50ppm/°C). The primary distinction is that the TL431BCLP offers better initial accuracy (±0.4%) compared to the original part (±1%). This substitution results in a smaller absolute error for the reference voltage and potentially higher system accuracy, constituting a forward-compatible upgrade. Both devices use the same TO-92-3 package, with identical physical dimensions and pinout, allowing for a direct drop-in replacement on the PCB.

2. TL1431IZ Substitution Conclusion The TL1431IZ is functionally capable of replacing the original TL431AILPG, but several key differences must be noted and their suitability for the application assessed. Functionally, it is also an adjustable shunt regulator with a matching voltage range (2.5V-36V) and current capability (100mA). Its nominal reference voltage is 2.5V (compared to onsemi's 2.495V). More critically, its temperature coefficient is specified at 100ppm/°C, which is significantly worse than the original part's typical 50ppm/°C. In environments with temperature variations, its output voltage drift will be approximately double that of the original device, potentially making it unsuitable for temperature-sensitive applications. Furthermore, while its package is also a TO-92 variant, it is described as "TO-226-2, TO-92-2". It is essential to strictly verify the pinout diagram in the ST datasheet to confirm its pin arrangement (Cathode, Anode, Ref) is fully compatible with the TO-92-3 package of the original part, preventing circuit damage due to pin definition mismatches. Substitution is feasible but requires acceptance of its inferior temperature stability and verification of package compatibility.

Analysis ID: 2474-50CD000

Based on part parameters and for reference only. Not to be used for procurement or production.