tcn75a Microchip Technology Inc., tcn75a Datasheet - Page 13

• Manufacturer Part Number: tcn75a
• Description: 2-wire Serial Temperature Sensor
• Manufacturer: Microchip Technology Inc.

5.3.1
The TCN75A has a 16-bit read-only Ambient
Temperature register that contains 9-bit to 12-bit
temperature data. (0.5°C to 0.0625°C resolutions,
respecively).
complement. The bit assignments, as well as the
corresponding resolution, is shown in the register
assignment below.
The refresh rate of this register depends on the
selected ADC resolution. It takes 30 ms (typ.) for 9-bit
data and 240 ms (typ.) for 12-bit data. Since this
register is double-buffered, the user can read the
register while the TCN75A performs Analog-to-Digital
REGISTER 5-2:
© 2006 Microchip Technology Inc.
bit 15
bit 7
Legend:
R = Readable bit
-n = Value at POR
Note 1:
Upper Half:
Lower Half:
2
-1
Sign
R-0
R-0
°C/bit
When the 0.5°C, 0.25°C or 0.125°C resolutions are selected, bit 6, bit 7 or bit 8 will remain clear <0>,
respectively.
AMBIENT TEMPERATURE
REGISTER (T
This
2
2
R-0
R-0
-2
6
data
AMBIENT TEMPERATURE REGISTER (T
°C
°C
A
)
is
W = Writable bit
‘1’ = Bit is set
formatted
2
2
R-0
R-0
-3
5
°C
°C
in
2
two’s
2
R-0
R-0
-4
4
°C
°C
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
conversion in the background. The decimal code to
ambient
Equation 5-2:
EQUATION 5-2:
2
R-0
R-0
3
Where:
0
°C
A
) - ADDRESS <
Code = TCN75A output in decimal
temperature
T
A
2
R-0
R-0
2
= Ambient Temperature (°C)
0
°C
T
A
=
Code 2
conversion
0000 0000
x = Bit is unknown
2
×
R-0
R-0
1
0
°C
TCN75A
4 –
DS21935C-page 13
>b
is
shown
2
R-0
R-0
0
0
°C
bit 8
bit 0
in