DS1920 Maxim, DS1920 Datasheet - Page 5

• Manufacturer Part Number: DS1920
• Description: The DS1920 provides direct-to-digital 9-bit temperature readings over a range of -55°C to +100°C in 0
• Manufacturer: Maxim

The most significant (sign) bit is duplicated into all of the bits in the upper MSB of the 2-byte
temperature register in memory. This “sign-extension” yields the 16-bit temperature readings as shown in
Table 1.
Higher resolutions may be obtained by the following procedure. First, read the temperature, and truncate
the 0.5°C bit (the LSB) from the read value. This value is TEMP_READ. The value left in the counter
may then be read. This value is the count remaining (COUNT_REMAIN) after the gate period has
ceased. The last value needed is the number of counts per degree C (COUNT_PER_C) at that
temperature. The actual temperature may be then be calculated by the user using the following formula:
TEMPERATURE MEASURING CIRCUITRY Figure 3
TEMPERATURE/DATA RELATIONSHIPS Table 1
TEMPERATURE
TEMPERATURE = TEMP_READ - 0.25 +
+100°C
+25°C
+½°C
-25°C
-55°C
+0°C
-½°C
00000000 11001000
00000000 00110010
00000000 00000001
00000000 00000000
11111111 11111111
11111111 11001110
11111111 10010010
DIGITAL OUTPUT
(BINARY)
5 of 22
(COUNT_PER
COUNT_PER_
_C
-
COUNT_REMA
DIGITAL OUTPUT
C
FFCEh
FFFFh
(HEX)
00C8h
FF92h
0032h
0001h
0000h
IN)
SET/CLEAR
LSB
DS1920