EMC1402-3-ACZL-TR Ver la hoja de datos (PDF) - SMSC -> Microchip

Número de pieza

componentes Descripción

Lista de partido

EMC1402-3-ACZL-TR

1°C Temperature Sensor with Beta Compensation

SMSC -> Microchip 

1°C Temperature Sensor with Beta Compensation

Datasheet

resistance, bulk resistance in the base and emitter of the temperature transistor. Typically, the error

caused by series resistance is +0.7°C per ohm. The EMC1402 automatically corrects up to 100 ohms

of series resistance.

5.6

Programmable External Diode Ideality Factor

The EMC1402 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 EMC1402 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.

5.7

Diode Faults

The EMC1402 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 5.8)

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 0.000degC (-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.

5.8

Consecutive Alerts

The EMC1402 contains 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 6.11 for more details on the consecutive alert function.

5.9

Digital Filter

To reduce the effect of noise and temperature spikes on the reported temperature, the External Diode

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 5.2 and Figure 5.3.

Revision 2.0 (08-10-12)

18

DATASHEET

SMSC EMC1402

Share Link: