emc1413 Standard Microsystems Corp., emc1413 Datasheet - Page 21

• Manufacturer Part Number: emc1413
• Description: 1?c Temperature Sensor With Beta Compensation And Selectable Address
• Manufacturer: Standard Microsystems Corp.

1°C Temperature Sensor with Beta Compensation and Selectable Address
Datasheet
APPLICATION NOTE: When monitoring a substrate transistor or CPU diode and beta compensation is enabled, the
SMSC EMC1413 / EMC1414
5.7
5.8
5.9
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 and 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.
The EMC1413 and EMC1414 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
5.8, "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 EMC1413 and 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
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 Figure 5.4, "Temperature Filter Step Response"
and Figure 5.5, "Temperature Filter Impulse Response".
Diode Faults
Consecutive Alerts
Digital Filter
Section 6.12, "Consecutive ALERT Register"
Ideality Factor should not be adjusted. Beta Compensation automatically corrects for most
ideality errors.
Alerts") and the temperature data reads 00h in the MSB and LSB registers (note:
DD
to DP, or a short from V
DATASHEET
21
for more details on the consecutive alert function.
DD
to DN.
Revision 1.37 (12-23-09)
Section