MCP9805-BE/ST Microchip Technology, MCP9805-BE/ST Datasheet - Page 14

• Manufacturer Part Number: MCP9805-BE/ST
• Description: IC,TEMPERATURE SENSOR,TSSOP,8PIN,PLASTIC
• Manufacturer: Microchip Technology

Specifications of MCP9805-BE/ST

• Rohs Compliant: YES
• Function: Temp Monitoring System (Sensor)
• Topology: ADC (Sigma Delta), Register Bank
• Sensor Type: Internal
• Sensing Temperature: -40°C ~ 125°C
• Output Type: I²C™/SMBus™
• Output Alarm: No
• Output Fan: Yes
• Voltage - Supply: 3 V ~ 3.6 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 8-TSSOP
• Temperature Threshold: Programmable
• Full Temp Accuracy: 3 C
• Digital Output - Bus Interface: I2C, SMBus
• Digital Output - Number Of Bits: 10 bit
• Supply Voltage (max): 3.6 V
• Supply Voltage (min): 3 V
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 20 C
• Supply Current: 500 uA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

MCP9805
4.1.4
The MCP9805 uses a band gap temperature sensor
circuit to output analog voltage proportional to absolute
temperature. An internal
analog voltage to a digital word. The converter resolu-
tion is set to 0.25 °C/LSb + sign (11-bit data). The digital
word is loaded to a 16-bit read-only Ambient Tempera-
ture register
in two’s complement format.
The T
Therefore, the user can access the register while, in the
background, the MCP9805 performs an analog-to-dig-
ital conversion of the band gap temperature sensor.
The temperature data from the
parallel to T
The T
conversion is shown in Equation 4-1:
REGISTER 4-5:
DS21977B-page 14
bit 15
bit 14
bit 13
bit 12
Upper-Half:
bit 15
Legend:
R = Readable bit
-n = Value at POR
T
Note 1: Not affected by the status of the Event output configuration (bits 5 to 0 of CONFIG) and T
A
A
Vs. T
A
R-0
register bits (bits 12 thru 0) are double-buffered.
magnitude in decimal to ambient temperature
2: Bit 1 may remain set ‘1’ for some devices indicating 2
CRIT
T
0
1
T
0
1
T
0
1
SIGN bit:
0
1
A
AMBIENT TEMPERATURE
REGISTER (T
A
A
A
Register 4-3.
depending on the state of the device calibration code.
(T
= T
= T
= T
= T
= T
= T
at t
= T
= T
vs. T
vs. T
vs. T
A
)
CONV
A
A
A
A
A
A
A
A
Lower-Half:
bit 7
2
that contains 11-bit temperature data
T
3
CRIT
UPPER
LOWER
A
°C/LSb
T
T
T
T
T
T
0°C
0°C
R-0
Vs. T
CRIT
CRIT
UPPER
UPPER
LOWER
LOWER
refresh rate.
AMBIENT TEMPERATURE REGISTER (T
(1)
R-0
(1)
(1)
bit:
UPPER
A
ADC is used to convert the
bit:
)
bit:
2
2
°C/LSb
R-0
T
W = Writable bit
‘1’ = bit is set
ADC is loaded in
A
Vs. T
R-0
LOWER
2
1
°C/LSb
R-0
SIGN
R-0
2
0
°C/LSb
R-0
U = Unimplemented bit, read as ‘0’
‘0’ = bit is cleared
EQUATION 4-1:
In addition, the T
and 13) to reflect the Event pin state. This allows the
user to identify the cause of the Event output trigger
(see Section 4.2.3 “Event Output Configuration”);
bit 15 is set to ‘1’ if T
bit 14 is set to ‘1’ if T
is set to ‘1’ if T
The T
conditions are described in Register 4-5.
Where:
2
7
Code = MCP9805 output magnitude in
°C/LSb 2
R-0
2
T
A
-3
-1
A
A
)
°C/LSb or 0.125°C temperature resolution,
°C/LSb 2
R-0
= Ambient Temperature (°C)
register bit assignment and boundary
decimal
ADDRESS ‘0000 0101’b
A
6
is less than T
°C/LSb 2
A
R-0
T
register uses three bits (bits 15, 14
-2
A
A
A
°C/LSb
is greater than T
R-0
is greater than or equal to T
DECIMAL CODE TO
TEMPERATURE
CONVERSION
=
© 2005 Microchip Technology Inc.
Code 2
x = bit is unknown
5
°C/LSb 2
R-0
LOWER
2 –
—
U-0
(2)
.
UPPER
4
°C/LSb
R-0
HYST
bit 8
and bit 13
U-0
—
= 0°C,
bit 0
CRIT
,