TL431ACLPR Replacement: TL431AFDT,215, AS431IAZTR-G1

Original Part

TL431ACLPR

Texas Instruments

Shunt Voltage Reference IC Adjustable 2.495V 36 VV ±1% 100 mA TO-92-3

Alternative Part

TL431AFDT,215

Nexperia USA Inc.

Shunt Voltage Reference IC Adjustable 2.495V 36 VV ±1% 100 mA TO-236AB

AS431IAZTR-G1

Diodes Incorporated

Shunt Voltage Reference IC Adjustable 2.5V 36 VV ±0.5% 100 mA TO-92

1. TL431AFDT,215 Substitution Conclusion The TL431AFDT,215 matches the original TL431ACLPR in all key electrical parameters, including the adjustable reference voltage of 2.495V, output voltage range, tolerance, and output current capability. Its cathode current requirement of 600 µA is also identical, making it functionally a direct drop-in replacement. The primary difference lies in the package: it changes from the through-hole TO-92-3 to the surface-mount SOT-23-3 (TO-236AB). Substitution therefore necessitates a PCB layout redesign to accommodate the different footprint and soldering process. Notably, this variant carries AEC-Q100 automotive-grade qualification, offering superior reliability and environmental robustness compared to commercial-grade parts, which presents it as a potential upgrade option.

2. AS431IAZTR-G1 Substitution Conclusion The AS431IAZTR-G1 is compatible with the original device in basic functionality (adjustable reference, output voltage range, output current) and package (TO-92-3), allowing for straightforward physical replacement. Key differences are as follows: its nominal reference voltage is 2.5V (a slight deviation from the original 2.495V), its tolerance is improved to ±0.5%, and most critically, its typical cathode operating current is reduced to 50 µA, significantly lower than the original 600 µA. This enables operation with lower bias current, which can reduce system standby power. However, it imposes a strict requirement that the original circuit must be able to start up and operate stably at such a low cathode current. If the original design (e.g., the divider resistor network) was optimized for the TL431's higher cathode current, a direct substitution may cause the reference to malfunction or fail to turn on properly under light-load conditions.

Analysis ID: D4C3-DB69000

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