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MAX1617AMEE+T

Category: Hardware
Product Number: MAX1617AMEE+T, MAX1617A

Hi!

When trying to measure the temperature with the MAX1617A sensor at high temperatures (+120 degrees), by gradually increasing the heat, the external REMOTE sensor reaches a temperature of about 110 degrees and makes a jump to the maximum value of +127, resulting in a temperature value of 0111_1111 in the temperature value register. During debugging, the following actions were performed:

1) When checking the RSL status registers, the OPEN flag is detected as zero, as it should be when the external transistor is connected. But when the temperature is displayed as +127, the RHIGH flag is set to 1 (while the ambient temperature is less than 127 degrees)

2) When the external sensor is gradually heated to 125 degrees at a temperature of about 110 degrees, the displayed temperature jumps to 127 degrees and an ALERT is triggered, caused by the upper temperature limit, which is set to a maximum of 127 degrees by default and programmatically.

3) The temperature measurement on the LOCAL sensor at the same temperature as for the REMOTE sensor is displayed correctly and does not have a sharp jump to the upper limit. The temperature output processing from the registers for the LOCAL and REMOTE sensors is identical, which eliminates a software error in value processing. 5) Various CONVERSION RATE values were tested programmatically, and the result did not change.
4) Various CONVERSION RATE values were tested programmatically, but the result did not change.
5) Schematically, various types of transistors and package types (for example, MMBT3904 from UMV and OnSemiconductor and other analogues with similar characteristics) were tested, and various capacitance values were installed in parallel with the transistor in diode mode (2200pF, 3300pF, and without any installed capacitance). The developed test board takes into account all the recommendations for the width and spacing of the DXP and DXN pins. The method of connecting directly to the chip pin was also tested.