EMC1403 Datasheet, PDF (23/42 Pages) SMSC Corporation – 1°C Temperature Sensor with Beta Compensation

1°C Temperature Sensor with Beta Compensation
Datasheet
Table 5.3 EMC1403 and EMC1404 Temperature Data Format (continued)
TEMPERATURE (°C)
1
64
65
127
127.875
128
190
191
>= 191.875
DEFAULT RANGE 0°C TO 127°C
000 0000 1000
010 0000 0000
010 0000 1000
011 1111 1000
011 1111 1111
011 1111 1111
Note 5.3
011 1111 1111
011 1111 1111
011 1111 1111
EXTENDED RANGE RANGE -64°C
TO 191°C
010 0000 1000
100 0000 0000
100 0000 1000
101 1111 1000
101 1111 1111
110 0000 0000
111 1111 0000
111 1111 1000
111 1111 1111
Note 5.4
Note 5.1 In default mode, all temperatures < 0°C will be reported as 0°C.
Note 5.2 In the extended range, all temperatures < -64°C will be reported as -64°C.
Note 5.3 For the default range, all temperatures > +127.875°C will be reported as +127.875°C.
Note 5.4 For the extended range, all temperatures > +191.875°C will be reported as +191.875°C.
5.12
Anti-parallel Diode Connections
The EMC1404 supports reading two external diodes on the same set of pins (DP2, DN2). These
diodes are connected as shown in Figure 5.2. Due to the anti-parallel connection of these diodes, both
diodes will be reverse biased by a V_BE voltage (approximately 0.7V). Because of this reverse bias,
only discrete thermal diodes (such as a 2N3904) are recommended to be placed on these pins.
5.13
External Diode Connections
The EMC1403 can be configured to measure a CPU substrate transistor, a discrete 2N3904 thermal
diode, or an AMD processor diode. The diodes can be connected in a variety of ways as indicated in
Figure 5.6.
The EMC1404 can be configured to measure a CPU substrate transistor, a discrete 2N3904 thermal
diode, or an AMD processor diode on the External Diode 1 channel only. The External Diode 2 and
External Diode 3 channels are configured to measure a pair of discrete anti-parallel diodes (shared on
pins DP2 and DN2). The supported configurations for the external diode channels are shown in
Figure 5.6.
SMSC EMC1403/EMC1404
23
DATASHEET
Revision 1.16 (03-15-07)