I am performing a worst case analysis of a circuit using the LM4050QML-SP Voltage Reference.
The datasheet provides VR tolerance (for IR = 60uA) at the temperature extremes of +125 oC (+/-5mV) and -55 oC (+/-4.5mv).
The datasheet also gives an Average Reverse Voltage Breakdown Coefficient of +/-17ppm/oC at high temp and +/-19ppm/oC at low temp.
Using these coefficients I get a tolerance of +/-4.35mV at +125 oC and +/-3.8mV at -55 oC.
If these two parameters describe the same phenomenon of increasing tolerance at extreme temperatures, why are the values different at the endpoints.
If these parameters are describing different phenomenon, I suppose I'll have to add them together for the worst case value.
Does anyone understand this?
Thanks
Yossi David,
The phenomenon is the same but the Vr test is an absolute voltage test and the dVr/dT test is a relative voltage test.Vr says at 25C Vz range =2.5V+/-2.5mV at 25C and Vz range =2.5V+/-5mV at 125C and Vz range =2.5V+/-4.5mV at -55CdVr/dT says for range T=25C to 125C, Vr(max)-Vr(min) < 15 * 2.5V/1e6*100CdVr/dT also says for range T=25C to -55C, Vr(max)-Vr(min) < 18 * 2.5V/1e6*80CRegards,Ron Michallick
Regards,Ronald MichallickLinear Applications
TI assumes no liability for applications assistance or customer product design. Customer is fully responsible for all design decisions and engineering with regard to its products, including decisions relating to application of TI products. By providing technical information, TI does not intend to offer or provide engineering services or advice concerning Customer's design. If Customer desires engineering services, the Customer should rely on its retained employees and consultants and/or procure engineering services from a licensed professional engineer (LPE).