AS431IAZTR-G1 Replacement: TL431ACLPRE3, LM431BCZXA

Original Part

AS431IAZTR-G1

Diodes Incorporated

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

Alternative Part

TL431ACLPRE3

Texas Instruments

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

LM431BCZXA

onsemi

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

1. TL431ACLPRE3 Substitution Conclusion The conclusion is a conditional substitution. The TL431ACLPRE3 is compatible with the original part in terms of core architecture, package, and adjustable output voltage range. However, key differences exist: its reference voltage nominal value is 2.495V (with a 5mV inherent system offset), its initial accuracy is ±1% (inferior to the original ±0.5%), and its typical cathode operating current (I_KA) is 600µA (12 times higher than the original 50µA). This part can be used as a direct replacement in applications where a slight degradation in initial accuracy is acceptable. However, in circuits with stringent requirements on system precision, low power consumption (especially battery-powered devices), or low operating current, direct substitution may lead to a significant increase in quiescent power dissipation, a slight shift in the reference value, and an overall reduction in system accuracy. A thorough re-evaluation of circuit performance is mandatory in such cases.

2. LM431BCZXA Substitution Conclusion The conclusion is also a conditional substitution. The LM431BCZXA is pin-compatible with the original part in package and voltage adjustment range. Its critical differentiating parameters are: a reference voltage nominal value of 2.495V with ±1% initial accuracy, a typical cathode operating current (I_KA) as high as 1mA (20 times the original value), and it explicitly specifies a typical temperature coefficient of 50ppm/°C (a parameter not defined for the original part). This device presents a viable option for applications operating over a wide temperature range where voltage drift stability is required and lower initial accuracy is acceptable. However, its extremely high cathode operating current will cause a substantial increase in the power dissipation of the reference circuit itself, severely limiting its suitability for direct use in any power-sensitive design. A recalculation of the system's power budget is essential prior to substitution.

Analysis ID: 0EBA-4293000

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