SE97 Datasheet, PDF (28/54 Pages) NXP Semiconductors – DDR memory module temp sensor with integrated SPD, 3.3 V

NXP Semiconductors
SE97
DDR memory module temp sensor with integrated SPD, 3.3 V
8.4 Temperature format
The temperature data from the temperature read back register is an 11-bit 2’s
complement word with the least significant bit (LSB) equal to 0.125 °C (resolution).
• A value of 019Ch will represent 25.75 °C
• A value of 07C0h will represent 124 °C
• A value of 1E64h will represent −25.75 °C.
The unused LSB (bit 0) is set to ‘0’. Bit 11 will have a resolution of 128 °C.
The upper 3 bits of the temperature register indicate Trip Status based on the current
temperature, and are not affected by the status of the EVENT output.
Table 14 lists the examples of the content of the temperature data register for positive and
negative temperature for two scenarios of status bits: status bits = 000b and
status bits = 111b.
Table 14. Degree Celsius and Temperature Data register
Temperature Content of Temperature Data register
Status bits = 000b
Status bits = 111b
Binary
Hex
Binary
+125 °C
000 0 01111101 000 0 07D0h 111 0 01111101 000 0
+25 °C
000 0 00011001 000 0 0190h
111 0 00011001 000 0
+1 °C
000 0 00000001 000 0 0010h
111 0 00000001 000 0
+0.25 °C
000 0 00000000 010 0 0004h
111 0 00000000 010 0
+0.125 °C
000 0 00000000 001 0 0002h
111 0 00000000 001 0
0 °C
000 0 00000000 000 0 0000h
111 0 00000000 000 0
−0.125 °C
000 1 11111111 111 0 1FFEh 111 1 11111111 111 0
−0.25 °C
000 1 11111111 110 0 1FFCh 111 1 11111111 110 0
−1 °C
000 1 11111111 000 0 1FF0h 111 1 11111111 000 0
−20 °C
000 1 11110100 000 0 1F40h
111 1 11110100 000 0
−25 °C
000 1 11100111 000 0 1E70h 111 1 11100111 000 0
−55 °C
000 1 11001001 000 0 1C90h 111 1 11001001 000 0
Hex
E7D0h
E190h
E010h
E004h
E002h
E000h
FFFEh
FFFCh
FFF0h
FF40h
FE70h
FC90h
SE97_5
Product data sheet
Rev. 05 — 6 August 2009
© NXP B.V. 2009. All rights reserved.
28 of 54