Multiple Channel 1°C Temperature Sensors with Beta Compensation
Datasheet
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 EMC1413 / EMC1414 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.
APPLICATION NOTE: When monitoring a substrate transistor or CPU diode and beta compensation is enabled, the
Ideality Factor should not be adjusted. Beta Compensation automatically corrects for most
ideality errors.
6.5
Diode Faults
The EMC1413 / EMC1414 detects 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
Section 6.6) and the temperature data reads 00h in the MSB and LSB registers (note: 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 VDD to DP, or a short from VDD to DN.
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 0.000°C (-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.
6.6
6.7
Consecutive Alerts
The EMC1413 / EMC1414 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 Section 7.12, "Consecutive ALERT Register" for more details on the consecutive alert function.
Digital Filter
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 (default) (see Section 7.18). The typical filter performance is shown in Figure 6.3 and
Figure 6.4.
Revision 1.41 (02-23-12)
SMSC EMC1413 / EMC1414
DATA2S2HEET
SMSC [ SMSC CORPORATION ]
