EMC1073-1-AIZL-TR SMSC, EMC1073-1-AIZL-TR Datasheet - Page 20

• Manufacturer Part Number: EMC1073-1-AIZL-TR
• Description: Board Mount Temperature Sensors SMBus Temp Sensor Selectable Address
• Manufacturer: SMSC

Specifications of EMC1073-1-AIZL-TR

• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Revision 1.39 (10-11-10)
5.4
5.5
5.6
5.7
When the ALERT pin is asserted in comparator mode, the corresponding high limit status bits will be
set. Reading these bits will not clear them until the ALERT pin is deasserted. Once the ALERT pin is
deasserted, the status bits will be automatically cleared.
The MASK bit will not block the ALERT pin in this mode, however the individual channel masks (see
Section
The EMC1073 and EMC1074 is designed for external diodes with an ideality factor of 1.008. Not all
external diodes, processor or discrete, will have this exact value. This variation of the ideality factor
introduces error in the temperature measurement which must be corrected for. This correction is
typically done using programmable offset registers. Since an ideality factor mismatch introduces an
error that is a function of temperature, this correction is only accurate within a small range of
temperatures. To provide maximum flexibility to the user, the EMC1073 and EMC1074 provides a 6-
bit register for each external diode where the ideality factor of the diode used is programmed to
eliminate errors across all temperatures.
The EMC1073 and EMC1074 detect an open on the DP and DN pins, and a short across the DP and
DN pins. For each temperature measurement made, the device checks for a diode fault on the external
diode channel(s). When a diode fault is detected, the ALERT pin asserts (unless masked, see
5.6, "Consecutive
the low limit will not be checked). A diode fault is defined as one of the following: an open between
DP and DN, a short from V
If a short occurs across DP and DN or a short occurs from DP to GND, the low limit status bit is set
and the ALERT pin asserts (unless masked). This condition is indistinguishable from a temperature
measurement of 0.000degC (-64°C in extended range) resulting in temperature data of 00h in the MSB
and LSB registers.
If a short from DN to GND occurs (with a diode connected), temperature measurements will continue
as normal with no alerts.
The EMC1073 and EMC1074 contain multiple consecutive alert counters. One set of counters applies
to the ALERT pin and the second set of counters applies to the THERM pin. Each temperature
measurement channel has a separate consecutive alert counter for each of the ALERT and THERM
pins. All counters are user programmable and determine the number of consecutive measurements
that a temperature channel(s) must be out-of-limit or reporting a diode fault before the corresponding
pin is asserted.
See
To reduce the effect of noise and temperature spikes on the reported temperature, the External Diode
1 channel uses a programmable digital filter. This filter can be configured as Level 1, Level 2, or
Disabled. The typical filter performance is shown in
and
Programmable External Diode Ideality Factor
Diode Faults
Consecutive Alerts
Digital Filter
Figure 5.5, "Temperature Filter Impulse
Section 6.12
6.11) will prevent the respective channel from asserting the ALERT pin.
for more details on the consecutive alert function.
Alerts") and the temperature data reads 00h in the MSB and LSB registers (note:
DD
to DP, or a short from V
DATASHEET
Multiple Channel 1°C Temperature Sensors with Selectable Address
20
Response".
Figure 5.4, "Temperature Filter Step Response"
DD
to DN.
SMSC EMC1073 / EMC1074
Datasheet
Section