The RNC90Y has been the benchmark for high precision established reliability discrete resistors since 1982. In 2000, Vishay achieved a technological breakthrough with the introduction of the commercial ultra precision low TCR Z201 resistor. This breakthrough has now allowed Vishay to introduce an established reliability "R" level very low TCR resistor. The RNC90Z TCR limit of 2 ppm/C over the extended range of - 55 C to + 175 C is a significant improvement over the existing RNC90Y specification. The RNC90Z is a direct replacement for the RNC90Y.