MCP9802 Microchip Technology Inc., MCP9802 Datasheet - Page 15

• Manufacturer Part Number: MCP9802
• Description: 2-wire High-accuracy Temperature Sensor
• Manufacturer: Microchip Technology Inc.

4.3.4.6
The fault queue feature can be used as a filter to lessen
the probability of spurious activation of the ALERT pin.
T
ber of conversion cycles selected using the Fault
Queue bits. Bit 3 and bit 4 of CONFIG can be used to
select up to six fault queue cycles. For example, if six
fault queues are selected, T
T
asserted as a comparator or an interrupt output.
This queue setting also applies for T
remain below T
before ALERT is deasserted (comparator mode) or
before another interrupt is asserted (interrupt mode).
4.3.4.7
The MCP9800/1/2/3 provides access to select the ADC
resolution from 9-bit to 12-bit using bit 6 and bit 5 of the
CONFIG register. The user can gain better insight into
the trends and characteristics of the ambient
temperature by using a finer resolution. Increasing the
resolution also reduces the quantization error.
Figure 2-4 shows accuracy versus resolution.
Table 4-1 shows the T
corresponding resolution.
TABLE 4-1:
 2004 Microchip Technology Inc.
A
SET
must remain above T
Bits
for six consecutive conversions before ALERT is
10
11
12
9
Fault Queue
HYST
ADC Resolution
°C/Bit (typ.)
Resolution
RESOLUTION AND
CONVERSION TIME
0.0625
0.125
0.25
A
0.5
for six consecutive conversions
register conversion time for the
SET
for the consecutive num-
A
must be greater than
Conversion time
t
CONV
HYST
120
240
ms (typ.)
30
60
. T
A
must
4.4
The MCP9800/1/2/3 has an internal Power-on Reset
(POR) circuit. If the power supply voltage V
down to the 1.7V (typ.) threshold, the device resets the
registers to the power-up default settings.
Table 4-2 shows the power-up default summary.
TABLE 4-2:
Register
CONFIG
Pointer
T
T
HYST
T
SET
Summary of Power-up Default
A
MCP9800/1/2/3
POWER-UP DEFAULTS
(Hex)
A000
Data
0000
9600
00
00
Continuous Conversion
Temperature register
Power-up Defaults
Active-Low Output
Comparator mode
9-bit Resolution
Fault Queue 1
DS21909B-page 15
80°C
75°C
0°C
DD
glitches