EMC1438 DATA SHEET (05/16/2016) DOWNLOAD

EMC1438
1°C Multiple Temperature Sensor
with Hardware Controlled Standby &
Hottest of Multiple Zones
PRODUCT FEATURES
Datasheet
General Description
Features
The EMC1438 is a high accuracy, low cost, System
Management Bus (SMBus) temperature sensor.
Advanced features such as Resistance Error Correction
(REC), Beta Compensation (to CPU diodes requiring the
BJT or transistor model) and automatic diode type
detection combine to provide a robust solution for
complex environmental monitoring applications.
Additionally, the hardware controlled STANDBY pin
allows for system level power shutdown to support
energy saving initiatives.
„
Hardware Set Standby Mode
„
Designed to support 45nm, 65nm, and 90nm CPU
diodes
Supports diodes requiring the BJT or transistor model
Resistance Error Correction (up to 100 Ohms)
Up to seven External Temperature Monitors
The EMC1438 monitors up to eight temperature
channels (up to seven external and one internal). The
device provides ±1°C accuracy for the internal and
external diode temperatures.
Temperature monitoring includes two tiers of protection:
one that can be masked and causes the ALERT pin to
be asserted, and the other that cannot be masked and
causes the THERM pin to be asserted.
— 200uA (typical) quiescent current in Standby
„
„
„
—
—
—
—
„
„
„
„
Internal Temperature Monitor
— ±1°C Accuracy
— 0.125°C Resolution
„
„
„
Programmable temperature limits for ALERT and
THERM
3.3V Supply Voltage
SMBus 2.0 interface
— Pin-selectable SMBus address
— Block Read and Write
Applications
„
±1°C Accuracy (40°C < TDIODE < 110°C)
0.125°C Resolution
Supports up to 2.2nF filter capacitor
Anti-parallel diodes for extra diode support and
compact design
Notebook Computers
Desktop Computers
Industrial
Embedded Applications
„
Available in a 16-pin 4mm x 4mm QFN Lead-free
RoHS Compliant package
Block Diagram
DP1
DN1
DP2 / DN3
DN2 / DP3
DP4 / DN5
DN4 / DP5
DP6 / DN7
DN6 / DP7
ADDR_SEL
SMCLK
Voltage Register
Analog
Mux
Antiparallel
Diode
SMSC EMC1438
Voltage to Temp
Conversion
External
Temp
Diode
Inputs
11 bit Σ Δ
ADC
Temp Registers
Hottest of
Comparison
Internal
Temp
Diode
DATASHEET
SMBus
Slave
Protocol
SMDATA
ALERT
THERM
STANDBY
Revision 1.0 (04-29-10)
1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
Ordering Information:
ORDERING NUMBER
PACKAGE
FEATURES
EMC1438-1-AP-TR
16-pin QFN 4mm x 4mm
(Lead-free RoHS compliant)
Up to 7 external diodes. “Hottest Of”
temperature comparison. ALERT and
THERM outputs. Standby low power
state. ALERT pin masked and APDs
enabled at power up.
EMC1438-2-AP-TR
16-pin QFN 4mm x 4mm
(Lead-free RoHS compliant)
Up to 7 external diodes. “Hottest Of”
temperature comparison. ALERT and
THERM outputs. Standby low power
state. ALERT pin masked and APDs
disabled at power up.
REEL SIZE IS 4,000 PIECES
This product meets the halogen maximum concentration values per IEC61249-2-21
For RoHS compliance and environmental information, please visit www.smsc.com/rohs
80 ARKAY DRIVE, HAUPPAUGE, NY 11788 (631) 435-6000, FAX (631) 273-3123
Copyright © 2010 SMSC or its subsidiaries. All rights reserved.
Circuit diagrams and other information relating to SMSC products are included as a means of illustrating typical applications. Consequently, complete
information sufficient for construction purposes is not necessarily given. Although the information has been checked and is believed to be accurate,
no responsibility is assumed for inaccuracies. SMSC reserves the right to make changes to specifications and product descriptions at any time without
notice. Contact your local SMSC sales office to obtain the latest specifications before placing your product order. The provision of this information
does not convey to the purchaser of the described semiconductor devices any licenses under any patent rights or other intellectual property rights of
SMSC or others. All sales are expressly conditional on your agreement to the terms and conditions of the most recently dated version of SMSC's
standard Terms of Sale Agreement dated before the date of your order (the "Terms of Sale Agreement"). The product may contain design defects or
errors known as anomalies which may cause the product's functions to deviate from published specifications. Anomaly sheets are available upon
request. SMSC products are not designed, intended, authorized or warranted for use in any life support or other application where product failure
could cause or contribute to personal injury or severe property damage. Any and all such uses without prior written approval of an Officer of SMSC
and further testing and/or modification will be fully at the risk of the customer. Copies of this document or other SMSC literature, as well as the Terms
of Sale Agreement, may be obtained by visiting SMSC’s website at http://www.smsc.com. SMSC is a registered trademark of Standard Microsystems
Corporation (“SMSC”). Product names and company names are the trademarks of their respective holders.
SMSC DISCLAIMS AND EXCLUDES ANY AND ALL WARRANTIES, INCLUDING WITHOUT LIMITATION ANY AND ALL IMPLIED WARRANTIES
OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, TITLE, AND AGAINST INFRINGEMENT AND THE LIKE, AND ANY AND
ALL WARRANTIES ARISING FROM ANY COURSE OF DEALING OR USAGE OF TRADE. IN NO EVENT SHALL SMSC BE LIABLE FOR ANY
DIRECT, INCIDENTAL, INDIRECT, SPECIAL, PUNITIVE, OR CONSEQUENTIAL DAMAGES; OR FOR LOST DATA, PROFITS, SAVINGS OR
REVENUES OF ANY KIND; REGARDLESS OF THE FORM OF ACTION, WHETHER BASED ON CONTRACT; TORT; NEGLIGENCE OF SMSC
OR OTHERS; STRICT LIABILITY; BREACH OF WARRANTY; OR OTHERWISE; WHETHER OR NOT ANY REMEDY OF BUYER IS HELD TO
HAVE FAILED OF ITS ESSENTIAL PURPOSE, AND WHETHER OR NOT SMSC HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
DAMAGES.
Revision 1.0 (04-29-10)
2
DATASHEET
SMSC EMC1438
1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
Table of Contents
Chapter 1 Delta . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.1
Delta from EMC1428 to EMC1438 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Chapter 2 Pin Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Chapter 3 Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.1
3.2
3.3
Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
SMBus Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Chapter 4 System Management Bus Interface Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.1
4.2
System Management Bus Interface Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.1.1
SMBus Start Bit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.1.2
SMBus Address and RD / WR Bit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.1.3
SMBus ACK and NACK Bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.1.4
SMBus Stop Bit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.1.5
SMBus Time-out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.1.6
SMBus and I2C Compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SMBus Protocols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2.1
Write Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2.2
Read Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2.3
Send Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2.4
Receive Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2.5
Block Write . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2.6
Block Read . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2.7
Alert Response Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13
13
13
14
14
14
14
14
15
15
15
15
15
16
16
Chapter 5 Product Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
5.1
5.2
5.3
5.4
5.5
5.6
5.7
Register Bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Temperature Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.3.1
Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.3.2
Limits and Fault Queues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.3.3
“Hottest Of” Comparison . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.3.4
Diode Faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ALERT Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.4.1
ALERT Pin Interrupt Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.4.2
ALERT Pin Comparator Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
THERM Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
System Configuration Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.6.1
Resistance Error Correction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.6.2
Beta Compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.6.3
Digital Averaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.6.4
Conversion Rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.6.5
Dynamic Averaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Diode Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17
18
18
18
18
19
19
20
20
20
20
21
21
21
21
21
21
22
Chapter 6 Register Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
6.1
6.2
6.3
Data Read Interlock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Temperature Data Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Status Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
SMSC EMC1438
3
DATASHEET
Revision 1.0 (04-29-10)
1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
6.4
6.5
6.6
6.7
6.8
6.9
6.10
6.11
6.12
6.13
6.14
6.15
6.16
6.17
6.18
6.19
6.20
6.21
6.22
6.23
6.24
6.25
Configuration Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Conversion Rate Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Temperature Limit Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
One Shot Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Therm Hysteresis Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Therm Limit Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
External Diode Fault Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Channel Interrupt Mask Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Consecutive ALERT Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Beta Configuration Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Hottest Temperature Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Hottest Temperature Status Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
High Limit Status Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Low Limit Status Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
THERM Limit Status Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
REC Configuration Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Hottest Configuration Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Channel Configuration Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Filter Control Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Product ID Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Manufacturer ID Register (FEh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Revision Register (FFh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
30
31
31
34
35
35
36
36
37
38
39
39
39
40
41
42
42
42
43
44
44
44
Chapter 7 Package Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
7.1
7.2
EMC1438 Package Drawing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Package Markings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
7.2.1
EMC1438 (16-Pin 4mm x 4mm QFN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Chapter 8 Datasheet Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Revision 1.0 (04-29-10)
4
DATASHEET
SMSC EMC1438
1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
List of Figures
Figure 2.1
Figure 4.1
Figure 5.1
Figure 5.2
Figure 7.1
Figure 7.2
Figure 7.3
Figure 7.4
EMC1438 Pin Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
SMBus Timing Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
System Diagram for EMC1438 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Diode Connections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
16-Pin QFN 4mm x 4mm Package Drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
16-Pin QFN 4mm x 4mm PCB Footprint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
16-Pin QFN 4mm x 4mm Package Dimensions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
EMC1438 Package Marking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
SMSC EMC1438
5
DATASHEET
Revision 1.0 (04-29-10)
1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
List of Tables
Table 2.1 EMC1438 Pin Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Table 2.2 Pin Type. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Table 3.1 Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Table 3.2 Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Table 3.3 SMBus Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Table 4.1 ADDR_SEL Resistor Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Table 4.2 Protocol Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Table 4.3 Write Byte Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Table 4.4 Read Byte Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Table 4.5 Send Byte Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Table 4.6 Receive Byte Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Table 4.7 Block Write Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Table 4.8 Block Read Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Table 4.9 Alert Response Address Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Table 5.1 Supply Current vs. Conversion Rate for EMC1438 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Table 6.1 Register Set in Hexadecimal Order . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Table 6.2 Temperature Data Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Table 6.3 Temperature Data Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Table 6.4 Status Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Table 6.5 Configuration Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Table 6.6 Conversion Rate Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Table 6.7 Conversion Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Table 6.8 Maximum Conversion Rate Per Temperature Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Table 6.9 Temperature Limit Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Table 6.10 One Shot Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Table 6.11 Therm Hysteresis Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Table 6.12 Therm Limit Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Table 6.13 External Diode Fault Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Table 6.14 Channel Interrupt Mask Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Table 6.15 Consecutive ALERT Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Table 6.16 Consecutive Alert Settings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Table 6.17 Beta Configuration Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Table 6.18 Beta Compensation Look Up Table. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Table 6.19 Hottest Temperature Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Table 6.20 Hottest Temperature Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Table 6.21 High Limit Status Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Table 6.22 Low Limit Status Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Table 6.23 THERM Limit Status Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Table 6.24 REC Configuration Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Table 6.25 Hottest Configuration Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Table 6.26 Channel Configuration Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Table 6.27 Filter Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Table 6.28 Product ID Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Table 6.29 Manufacturer ID Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Table 6.30 Revision Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Table 8.1 Customer Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Revision 1.0 (04-29-10)
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DATASHEET
SMSC EMC1438
1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
Chapter 1 Delta
1.1
Delta from EMC1428 to EMC1438
1. Order numbers EMC1438-1 and EMC1438-2.
2. Pin 5 was changed from TRIP_SET to ADDR_SEL.
3. Pin 6 was changed from SYS_SHDN to THERM.
4. Pin 13 was changed from N/C to STANDBY.
5. Added Standby low power state (see Section 5.2, "Power States") and STANDBY register bit (see
Section 6.4, "Configuration Register").
6. Added pin-selectable SMBus address (see Section 4.1.2, "SMBus Address and RD / WR Bit").
7. Added support for SMBus block read and write.
8. Changed default for MASK_ALL bit to 1, which prevents ALERT# pin assertion in interrupt mode
(see Section 6.4, "Configuration Register").
9. Removed SYS_SHDN Configuration Register 1Dh.
10. Changed default Channel Interrupt Mask Register 1Fh from F0h to 00h so all of the enabled
channels will assert the ALERT pin in comparator mode (see Section 6.11, "Channel Interrupt Mask
Register").
11. EMC1438-1 changed default Channel Configuration Register 3Bh from 00h to 0Eh so all of the
DPx/DNx and DNx/DPx pins power up with APD enabled, thereby enabling all temperature
channels at power up (see Section 6.21, "Channel Configuration Register"). EMC1438-2 leaves the
register default set at 00h.
SMSC EMC1438
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DATASHEET
Revision 1.0 (04-29-10)
1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
VDD
DP6 / DN7
DN6 / DP7
STANDBY
16
15
14
13
Chapter 2 Pin Description
12
SMCLK
11
SMDATA
3
10
DP4 / DN5
4
9
DN4 / DP5
7
8
GND
DN2 / DP3
ALERT
DP2 / DN3
6
2
THERM
DN1
EMC1438
16-pin QFN
5
1
ADDR_SEL
DP1
Figure 2.1 EMC1438 Pin Diagram
Table 2.1 EMC1438 Pin Description
PIN
NUMBER
NAME
1
DP1
DP1 - External Diode 1 positive (anode) connection.
AIO
2
DN1
External Diode 1 negative (cathode) connection.
AIO
3
DP2 / DN3
External Diode 2 positive (anode) connection and External
Diode 3 negative (cathode) connection
AIO
4
DN2 / DP3
External diode 2 negative (cathode) connection and External
Diode 3 positive (anode) connection
AIO
5
ADDR_SEL
Selects SMBus address via pull-down resistor.
6
THERM
Active low output - requires pull-up resistor. If not used,
connect to Ground.
OD (5V)
7
ALERT
Active low interrupt - requires pull-up resistor. If not used,
connect to Ground.
OD (5V)
8
GND
Revision 1.0 (04-29-10)
FUNCTION
Ground Connection
TYPE
AI
Power
8
DATASHEET
SMSC EMC1438
1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
Table 2.1 EMC1438 Pin Description (continued)
PIN
NUMBER
NAME
FUNCTION
TYPE
9
DN4 / DP5
External diode 4 negative (cathode) connection and External
Diode 5 positive (anode) connection
AIO
10
DP4 / DN5
External Diode 4 positive (anode) connection and External
Diode 5 negative (cathode) connection
AIO
11
SMDATA
SMBus Data input/output - requires pull-up resistor
12
SMCLK
SMBus Clock input - requires pull-up resistor
DI (5V)
13
STANDBY
Active low input that places the device into the Standby
state. If not used, connect to VDD.
DI (5V)
14
DN6 / DP7
External diode 6 negative (cathode) connection and External
Diode 7 positive (anode) connection
AIO
15
DP6 / DN7
External Diode 6 positive (anode) connection and External
Diode 7 negative (cathode) connection
AIO
16
VDD
Power supply
DIOD (5V)
Power
The pin types are described Table 2.2. All pins labeled (5V) are 5V tolerant.
APPLICATION NOTE: For the 5V tolerant pins that have a pull-up resistor, the voltage difference between VDD and
the pull-up voltage must never exceed 3.6V.
Table 2.2 Pin Type
PIN TYPE
Power
FUNCTION
Used to supply either VDD or GND to the device
DI
5V tolerant digital input
OD
5V tolerant Open drain digital output. Requires a pull-up resistor
DIOD
AIO
AI
SMSC EMC1438
5V tolerant bi-directional digital input / open-drain output. Requires a pull-up resistor.
Analog input / output used for external diodes or analog inputs
Analog Input - this pin is used as an input for analog signals.
9
DATASHEET
Revision 1.0 (04-29-10)
1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
Chapter 3 Electrical Specifications
3.1
Absolute Maximum Ratings
Table 3.1 Absolute Maximum Ratings
DESCRIPTION
RATING
UNIT
Supply Voltage (VDD)
-0.3 to 4.0
V
Voltage on 5V tolerant pins (V5VT_pin)
-0.3 to 5.5
V
0 to 3.6
V
-0.3 to VDD +0.3
V
Operating Temperature Range
-40 to +125
°C
Storage Temperature Range
-55 to +150
°C
Voltage on 5V tolerant pins (|V5VT_pin - VDD|) (see Note 3.1)
Voltage on any other pin to Ground
Lead Temperature Range
Refer to JEDEC Spec. J-STD-020
QFN-16 Package Power Dissipation (see Note 3.2)
Junction to Ambient (θJA) (see Note 3.3)
ESD Rating, All pins HBM
0.5W up to TA = 85°C
W
58
°C/W
2000
V
Note: Stresses at or above those listed could cause permanent damage to the device. This is a stress
rating only and functional operation of the device at any other condition above those indicated
in the operation sections of this specification is not implied. Prolonged stresses above the
stated operating levels and below the Absolute Maximum Ratings may degrade device
performance and lead to permanent damage.
Note 3.1
For the 5V tolerant pins that have a pull-up resistor, the pull-up voltage must not exceed
3.6V when the device is unpowered.
Note 3.2
The Package Power Dissipation specification assumes a thermal via design with the
thermal landing soldered to the PCB ground plane with four 12 mil vias.
Note 3.3
Junction to Ambient (JA) is dependent on the design of the thermal vias. Without thermal
vias and a thermal landing, the θJA is approximately 60°C/W including localized PCB
temperature increase.
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DATASHEET
SMSC EMC1438
1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
3.2
Electrical Specifications
Table 3.2 Electrical Specifications
VDD = 3.0V to 3.6V, TA = -40°C to 125°C, all typical values at TA = 27°C unless otherwise noted.
CHARACTERISTIC
SYMBOL
MIN
TYP
MAX
UNITS
CONDITIONS
DC Power
Supply Voltage
VDD
Supply Current
Standby Supply Current
3.0
3.3
3.6
V
IDD
395
450
uA
1 conversion / sec, dynamic
averaging disabled
IDD
700
960
uA
4 conversions / sec, dynamic
averaging enabled
ISTBY
200
uA
Monitoring disabled.
Internal Temperature Monitor
Temperature Accuracy
±0.25
Temperature Resolution
±1
°C
0°C < TA < 100°C
±2
°C
-40°C < TA < 125°C
0.125
°C
External Temperature Monitor
Temperature Accuracy
Temperature Resolution
±0.25
±1
°C
+40°C < TDIODE < +110°C
0°C < TA < 110°C
±0.5
±2
°C
-40°C < TDIODE < 127°C
0.125
°C
ms
default settings
2.7
nF
Connected across external diode
100
Ω
In series with DP and DN lines
Conversion Time all
Channels
tCONV
170
Capacitive Filter
CFILTER
2.2
Resistance Error
Correction
RSERIES
ALERT and THERM pins
Output Low Voltage
VOL
0.4
V
ISINK = 8mA
Leakage Current
ILEAK
±5
uA
powered or unpowered
TA < 85°C
pull-up voltage < 3.6V
SMCLK, SMDATA, and STANDBY pins
Input High Voltage
VIH
2.0
VDD
V
5V Tolerant
Input Low Voltage
VIL
-0.3
0.8
V
5V Tolerant
Input High/Low Current
IIH / IIL
±5
uA
Powered or unpowered
TA < 85°C
SMSC EMC1438
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DATASHEET
Revision 1.0 (04-29-10)
1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
Table 3.2 Electrical Specifications (continued)
VDD = 3.0V to 3.6V, TA = -40°C to 125°C, all typical values at TA = 27°C unless otherwise noted.
CHARACTERISTIC
SYMBOL
MIN
TYP
MAX
UNITS
CONDITIONS
Power Up Timing
First conversion ready
tCONV_f
300
ms
Time after power up before all
channels updated with valid data
SMBus delay
tSMB_d
25
ms
Delay before SMBus
communications should be sent by
host
3.3
SMBus Electrical Characteristics
Table 3.3 SMBus Electrical Specifications
VDD = 3.0V to 3.6V, TA = -40°C to 125°C, all typical values are at TA = 27°C unless otherwise noted.
CHARACTERISTIC
SYMBOL
MIN
TYP
MAX
UNITS
CONDITIONS
SMBus Interface
Hysteresis
Input Capacitance
CIN
Output Low Sink Current
IOL
420
mV
5
pF
8.2
15
mA
SMDATA = 0.4V
SMBus Timing
Clock Frequency
fSMB
Spike Suppression
tSP
Bus free time Start to
Stop
tBUF
1.3
us
Hold Time: Start
tHD:STA
0.6
us
Setup Time: Start
tSU:STA
0.6
us
Setup Time: Stop
tSU:STP
0.6
us
Data Hold Time
tHD:DAT
0
us
Data Setup Time
tSU:DAT
100
ns
Clock Low Period
tLOW
1.3
us
Clock High Period
tHIGH
0.6
us
Clock/Data Fall time
tFALL
300
ns
Min = 20+0.1CLOAD ns
Clock/Data Rise time
tRISE
300
ns
Min = 20+0.1CLOAD ns
fSMB > 100kHz
Clock/Data Rise time
tRISE
1000
ns
Min = 20+0.1CLOAD ns
fSMB < 100kHz
Capacitive Load
CLOAD
400
pF
per bus line
Revision 1.0 (04-29-10)
10
12
400
kHz
50
ns
DATASHEET
SMSC EMC1438
1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
Chapter 4 System Management Bus Interface Protocol
4.1
System Management Bus Interface Protocol
The EMC1438 communicates with a host controller, such as an SMSC SIO, through the SMBus. The
SMBus is a two-wire serial communication protocol between a computer host and its peripheral
devices. A detailed timing diagram is shown in Figure 4.1. Stretching of the SMCLK signal is supported;
however, the EMC1438 will not stretch the clock signal.
T HIGH
T LOW
T HD:STA
T SU:STO
T FALL
SMCLK
T RISE
T HD:STA
T HD:DAT
T SU:DAT
T SU:STA
SMDATA
T BUF
S
P
S
S - Start Condition
P - Stop Condition
P
Figure 4.1 SMBus Timing Diagram
4.1.1
SMBus Start Bit
The SMBus Start bit is defined as a transition of the SMBus Data line from a logic ‘1’ state to a logic
‘0’ state while the SMBus Clock line is in a logic ‘1’ state.
4.1.2
SMBus Address and RD / WR Bit
The SMBus Address Byte consists of the 7-bit client address followed by a 1-bit RD / WR indicator. If
this RD / WR bit is a logic ‘0’, the SMBus host is writing data to the client device. If this RD / WR bit
is a logic ‘1’, the SMBus host is reading data from the client device.
The EMC1438 SMBus address is determined by a single resistor connected between ground and the
ADDR_SEL pin, as shown in Table 4.1.
Table 4.1 ADDR_SEL Resistor Setting
RESISTOR
(+/-10%)
SMBUS ADDRESS
RESISTOR
(+/- 10%)
SMBUS ADDRESS
GND
1001_100(r/w)
1500
1001_001(r/w)
270
1001_101(r/w)
2700
1001_010(r/w)
560
1001_110(r/w)
5600
1001_011(r/w)
1000
1001_111(r/w)
>18000
0011_000(r/w)
All SMBus Data bytes are sent most significant bit first and composed of 8-bits of information.
SMSC EMC1438
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1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
4.1.3
SMBus ACK and NACK Bits
The SMBus client will acknowledge all data bytes that it receives (as well as the client address if it
matches and the ARA address if the ALERT pin is asserted). This is done by the client device pulling
the SMBus Data line low after the 8th bit of each byte that is transmitted.
The host will NACK (not acknowledge) the data received from the client by holding the SMBus data
line high after the 8th data bit has been sent.
4.1.4
SMBus Stop Bit
The SMBus Stop bit is defined as a transition of the SMBus Data line from a logic ‘0’ state to a logic
‘1’ state while the SMBus clock line is in a logic ‘1’ state. When the EMC1438 detects an SMBus Stop
bit, and it has been communicating with the SMBus protocol, it will reset its client interface and prepare
to receive further communications.
4.1.5
SMBus Time-out
The EMC1438 includes an SMBus time-out feature. Following a 30ms period of inactivity on the
SMBus, the device will time-out and reset the SMBus interface.
The time-out functionality defaults to disabled and can be enabled by writing to the TIMEOUT bit (see
Section 6.12, "Consecutive ALERT Register").
4.1.6
SMBus and I2C Compliance
The major differences between SMBus and I2C devices are highlighted here. For complete compliance
information, refer to the SMBus 2.0 specification.
1. Minimum frequency for SMBus communications is 10kHz.
2. The client protocol will reset if the clock is held at a logic ‘0’ for longer than 30ms. This time-out
functionality is disabled by default.
3. The client protocol will reset if both the clock and data lines are held at a logic ‘1’ for longer than
150us. This function is disabled by default.
4. I2C devices do not support the Alert Response Address functionality (which is optional for SMBus).
4.2
SMBus Protocols
The EMC1438 is SMBus 2.0 compatible and supports Send Byte, Read Byte, Receive Byte, Write
Byte, Block Read, and Block Write as valid protocols. It will respond to the Alert Response Address
protocol but is not in full compliance.
All of the below protocols use the convention in Table 4.2.
Table 4.2 Protocol Format
DATA SENT
TO DEVICE
DATA SENT TO
THE HOST
Attempting to communicate with the EMC1438 SMBus interface with an invalid slave address or invalid
protocol will result in no response from the device and will not affect its register contents.
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1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
4.2.1
Write Byte
The Write Byte is used to write one byte of data to the registers as shown below Table 4.3:
Table 4.3 Write Byte Protocol
START
SLAVE
ADDRESS
WR
ACK
REGISTER
ADDRESS
ACK
REGISTER
DATA
ACK
STOP
1 -> 0
YYYY_YYY
0
0
XXh
0
XXh
0
0 -> 1
4.2.2
Read Byte
The Read Byte protocol is used to read one byte of data from the registers as shown in Table 4.4.
Table 4.4 Read Byte Protocol
START
SLAVE
ADDRESS
WR
ACK
REGISTER
ADDRESS
ACK
START
SLAVE
ADDRESS
RD
ACK
REGISTER
DATA
NACK
STOP
1-> 0
YYYY_YYY
0
0
XXh
0
0 -> 1
YYYY_YYY
1
0
XXh
1
0 -> 1
4.2.3
Send Byte
The Send Byte protocol is used to set the internal address register pointer to the correct address
location. No data is transferred during the Send Byte protocol as shown in Table 4.5.
Table 4.5 Send Byte Protocol
START
SLAVE
ADDRESS
WR
ACK
REGISTER
ADDRESS
ACK
STOP
1 -> 0
YYYY_YYY
0
0
XXh
0
1 -> 0
4.2.4
Receive Byte
The Receive Byte protocol is used to read data from a register when the internal register address
pointer is known to be at the right location (e.g. set via Send Byte). This is used for consecutive reads
of the same register as shown in Table 4.6.
Table 4.6 Receive Byte Protocol
START
SLAVE
ADDRESS
RD
ACK
REGISTER DATA
NACK
STOP
1 -> 0
YYYY_YYY
1
0
XXh
1
1 -> 0
4.2.5
Block Write
The Block Write is used to write multiple data bytes to a group of contiguous registers, as shown in
Table 4.7. It is an extension of the Write Byte Protocol.
SMSC EMC1438
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1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
Table 4.7 Block Write Protocol
START
SLAVE
ADDRESS
WR
ACK
REGISTER
ADDRESS
ACK
REGISTER
DATA
ACK
1 ->0
YYYY_YYY
0
0
XXh
0
XXh
0
REGISTER
DATA
ACK
REGISTER
DATA
ACK
...
REGISTER
DATA
ACK
STOP
XXh
0
XXh
0
...
XXh
0
0 -> 1
4.2.6
Block Read
The Block Read is used to read multiple data bytes from a group of contiguous registers, as shown in
Table 4.8. It is an extension of the Read Byte Protocol.
Table 4.8 Block Read Protocol
START
SLAVE
ADDRESS
WR
ACK
REGISTER
ADDRESS
ACK
START
SLAVE
ADDRESS
RD
ACK
REGISTER
DATA
1->0
YYYY_YYY
0
0
XXh
0
1 ->0
YYYY_YYY
1
0
XXh
ACK
REGISTER
DATA
ACK
REGISTER
DATA
ACK
REGISTER
DATA
ACK
...
REGISTER
DATA
NACK
STOP
0
XXh
0
XXh
0
XXh
0
...
XXh
1
0 -> 1
4.2.7
Alert Response Address
The ALERT output can be used as a processor interrupt or as an SMBus Alert.
When it detects that the ALERT pin is asserted, the host will send the Alert Response Address (ARA)
to the general address of 0001_100b. All devices with active interrupts will respond with their client
address as shown in Table 4.9.
Table 4.9 Alert Response Address Protocol
START
ALERT
RESPONSE
ADDRESS
RD
ACK
DEVICE
ADDRESS
NACK
STOP
1 -> 0
0001_100
1
0
YYYY_YYY
1
1 -> 0
The EMC1438 will respond to the ARA in the following way if the ALERT pin is asserted:
1. Send Slave Address and verify that full slave address was sent (i.e. the SMBus communication
from the device was not prematurely stopped due to a bus contention event).
2. Set the MASK bit to clear the ALERT pin.
APPLICATION NOTE: The ARA does not clear the Status Register. If the MASK bit is cleared prior to the Status
Register being cleared, the ALERT pin will be reasserted.
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Datasheet
Chapter 5 Product Description
The EMC1438 is an SMBus temperature sensor that monitors up to seven (7) external diodes and one
internal diode.
Thermal management is performed in cooperation with a host device. This consists of the host reading
the temperature data of both the external and internal temperature diodes of the EMC1438 and using
that data to control the speed of one or more fans.
The EMC1438 provides two levels of monitoring. The first EMC1438 provides a maskable ALERT
signal to the host when measured temperatures meet or exceed user programmable limits. This allows
the EMC1438 to be used as an independent thermal watchdog to warn the host of temperature hot
spots without constant monitoring by the host. The second level of monitoring provides a non-maskable
interrupt on the THERM pin if the measured values meet or exceed a second programmable limit.
Because the EMC1438 automatically corrects for temperature errors due to series resistance in
temperature diode lines, there is greater flexibility in where external diodes are positioned and better
measurement accuracy than previously available devices without resistance error correction. As well,
the automatic beta detection feature means that there is no need to program the device according to
which type of diode is present. Therefore, the device can power up ready to operate for any system
configuration including those diodes that require the BJT or transistor model.
Figure 5.1 shows a system level block diagram of the EMC1438.
VDD
CPU
DP1
EMC1438
DN1
Host
THERM
SMDATA
SMCLK
SMBus
Interface
ALERT
Optional
antiparallel
diodes
DP2 / DN3
Optional
antiparallel
diodes
DP4 / DN5
DN4 / DP5
STANDBY
Optional
antiparallel
diodes
DP6 / DN7
ADDR_SEL
DN2 / DP3
DN6 / DP7
Figure 5.1 System Diagram for EMC1438
5.1
Register Bits
Unless otherwise stated when a bit is “set”, it is written to a logic ‘1’. Likewise when a bit is “cleared”,
it is written to a logic ‘0’.
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5.2
Power States
The EMC1438 contains two power states that are determined by the STANDBY pin. They are:
1. Active - This power state is enabled when the STANDBY pin is held at a logic ‘1’ and when the
STANDBY bit is cleared (see Section 6.4, "Configuration Register"). In this state, the device is fully
active and monitoring all active channels.
2. Standby - This power state is enabled when the STANDBY pin is held at a logic ‘0’ or when the
STANDBY bit is set (see Section 6.4, "Configuration Register"). In this state, the device is powered
down. It will not sample any of the channels nor will it check limits or assert the ALERT or THERM
pin. The device will respond to SMBus commands normally and the user may initiate a “One-Shot”
command (see Section 6.7, "One Shot Register") which will cause the device to measure all active
channels and then return to the Standby state. It will compare the measured temperature against
the limits, but will not assert the ALERT or THERM pins.
APPLICATION NOTE: To clear status bits while the device is in Standby, initiate the “One-Shot” command with the
error conditions removed and read the status registers. When the device is returned to the
Active state, the Status registers will be cleared and then updated after the first conversion
time. The ALERT and THERM pins cannot be asserted until after the first conversion is
completed after coming out of Standby.
5.3
Temperature Monitoring
The EMC1438 can monitor the temperature of up to seven (7) externally connected diodes as well as
the internal or ambient temperature.
5.3.1
Status
The EMC1438 provides a register that summarizes error conditions (see Section 6.3, "Status Register")
as well as separate registers to identify the specific channel(s) causing specific error conditions (see
Section 6.15, "Hottest Temperature Status Register", Section 6.16, "High Limit Status Register",
Section 6.17, "Low Limit Status Register", Section 6.10, "External Diode Fault Register", and Section
6.18, "THERM Limit Status Register").
The summary Status Register bits are set whenever a bit is set in one of the specific status registers.
These bits are set regardless of masking.
5.3.2
Limits and Fault Queues
The EMC1438 provides programmable high, low, and therm limits for each channel (see Section 6.6,
"Temperature Limit Registers" and Section 6.9, "Therm Limit Registers"). When a temperature channel
limit is exceeded for a programmable number of consecutive readings (fault queue - see below), the
specific limit status register is updated as well as the summary Status Register.
The EMC1438 contains multiple fault queue counters. Each out of limit error and diode fault condition
has its own counter associated with it. The counters are user programmable and determine the number
of consecutive measurements that a temperature channel must be out-of-limit or reporting a diode fault
before the corresponding status bits are set (see Section 6.12, "Consecutive ALERT Register"). Each
counter is incremented whenever the corresponding channel exceeds the appropriate limit (e.g. if
External Diode 1 exceeds its high limit, it will increment its high counter). Additionally, each counter is
reset if the condition has been removed.
The THERM fault counter is incremented whenever any of the measurements exceed the
corresponding THERM Limit. If the temperature drops below the THERM limit minus the corresponding
hysteresis (see Section 6.8, "Therm Hysteresis Register"), the counter is reset. If the programmed
number of consecutive measurements exceed the THERM Limit, the corresponding THERM Limit
status bit is set. Once the status bit is set, the consecutive THERM counter will not reset until the
corresponding temperature drops below the appropriate limit minus the corresponding hysteresis.
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When the ALERT pin is configured as a comparator (see Section 5.4.2, "ALERT Pin Comparator
Mode"), only the high limit fault counter is used; it is incremented if the measured temperature meets
or exceeds the High Limit. The fault queue counters for low limit and diode fault are not used, so the
applicable status bits are updated after a single out-of-limit or diode fault and the ALERT pin will not
be asserted. Once the high limit fault counter reaches the programmed limit, the ALERT pin will be
asserted (if not masked), but the counter will not be reset. It will remain set until the temperature drops
below the High Limit minus the THERM Hysteresis value (see Section 6.8, "Therm Hysteresis
Register").
The following is an example of how the counters work. If the CALRT[2:0] bits are set for 4 consecutive
alerts on an EMC1438 device, the high limits are set at 70°C, and none of the channels are masked,
the status bits will be asserted after the following four measurements:
1. Internal Diode reads 71°C and both external diodes read 69°C. Consecutive alert counter for INT
is incremented to 1.
2. Both the Internal Diode and the External Diode 1 read 71°C and External Diode 2 reads 68°C.
Consecutive alert counter for INT is incremented to 2 and for EXT1 is set to 1.
3. The External Diode 1 reads 71°C and both the Internal Diode and External Diode 2 read 69°C.
Consecutive alert counter for INT and EXT2 are cleared and EXT1 is incremented to 2.
4. The Internal Diode reads 71°C and both external diodes read 71°C. Consecutive alert counter for
INT is set to 1, EXT2 is set to 1, and EXT1 is incremented to 3.
5. The Internal Diode reads 71°C and both the external diodes read 71°C. Consecutive alert counter
for INT is incremented to 2, EXT2 is set to 2, and EXT1 is incremented to 4. The HIGH status bit
are set for EXT1 and the ALERT pin is asserted. The EXT1 counter is reset to 0 and all other
counters hold the last value until the next temperature measurement.
5.3.3
“Hottest Of” Comparison
At the end of every measurement cycle, the EMC1438 compares all of the user selectable External
Diode channels (see Section 6.20, "Hottest Configuration Register") to determine which of these
channels is reporting the hottest temperature. The hottest temperature is stored in the Hottest
Temperature Registers and the appropriate status bit in the Hottest Status Register is set (see Section
6.15, "Hottest Temperature Status Register"). If multiple temperature channels measure the same
temperature and are equal to the hottest temperature, the hottest status will be based on the
measurement order.
As an optional feature, the EMC1438 can also flag an event if the hottest temperature channel changes
(see Section 6.21, "Channel Configuration Register"). For example, suppose that External Diode
channels 1, 3, and 4 are programmed to be compared in the “Hottest Of” Comparison. If the External
Diode 1 channel reports the hottest temperature of the three, its temperature is copied into the Hottest
Temperature Registers (in addition to the External Diode 1 Temperature registers) and it is flagged in
the Hottest Status bit. If, on the next measurement, the External Diode 3 channel temperature has
increased such that it is now the hottest temperature, the EMC1438 can flag this event as an interrupt
condition and assert the ALERT pin.
5.3.4
Diode Faults
The EMC1438 actively detects an open and short condition on each measurement channel. When a
diode fault is detected and meets the criteria (see Section 5.3.2, "Limits and Fault Queues"), the
temperature data MSByte is forced to a value of 80h, the FAULT bit is set in the Status Register, and
the bit corresponding to the channel is set in the External Diode Fault Register (see Section 6.10,
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"External Diode Fault Register"). When an external diode channel is configured to operate in APD
mode, the circuitry will detect independent open fault conditions; however, a short condition will be
shared between the APD channels.
5.4
ALERT Output
The ALERT pin is an open drain output and has two modes of operation: interrupt mode and
comparator mode. The mode of the ALERT output is selected via the ALERT / COMP bit (see Section
6.4, "Configuration Register").
5.4.1
ALERT Pin Interrupt Mode
When configured to operate in interrupt mode and enabled, the ALERT pin asserts low when an out
of limit measurement (> high limit or < low limit) is detected on any diode or when a diode fault is
detected. The ALERT pin will remain asserted as long as an out-of-limit condition remains. Once the
out-of-limit condition has been removed, the ALERT pin will remain asserted until the appropriate
specific status register bits are cleared (Section 5.3.1, "Status"). Each channel is subject to the fault
queue (see Section 5.3.2, "Limits and Fault Queues").
The MASK_ALL bit (see Section 6.4, "Configuration Register") can be set to ‘1’, so the ALERT pin is
masked. Alternatively, the MASK_ALL bit can be set to ‘0’ and individual channels can be masked by
setting corresponding bits in the Channel Interrupt Mask Register (see Section 6.11, "Channel Interrupt
Mask Register"). When the ALERT pin is masked, it is de-asserted and remains de-asserted until the
mask is removed by the user.
The ALERT pin is used as an interrupt signal or as an SMBus Alert signal that allows an SMBus slave
to communicate an error condition to the master. One or more ALERT outputs can be hard-wired
together.
5.4.2
ALERT Pin Comparator Mode
When the ALERT pin is configured to operate in comparator mode, it will be asserted if any of the
measured temperatures meets or exceeds the respective high limit. Low temperature out of limit and
diode faults will not assert the ALERT pin. The ALERT pin will remain asserted until all temperatures
drop below the corresponding high limit minus the THERM Hysteresis value. Each channel is subject
to the high limit fault queue (see Section 5.3.2, "Limits and Fault Queues").
When the ALERT pin is asserted in comparator mode, the HIGH status bit in the Status Register and
the appropriate bit in the High Limit Status Register 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_ALL bit will not block the ALERT pin in this mode; however, the individual channel masks
(see Section 6.11, "Channel Interrupt Mask Register") will prevent the respective channel from
asserting the ALERT pin, although the status bits will still be set.
5.5
THERM Output
The THERM pin is asserted independently of the ALERT pin and cannot be masked. The temperature
is compared against the corresponding THERM Limit (see Section 6.9, "Therm Limit Registers").
Whenever any of the measured temperatures linked to the THERM pin meet or exceed the THERM
criteria (see Section 5.3.2, "Limits and Fault Queues"), the THERM pin is asserted. Once it has been
asserted, it will remain asserted until all measured temperatures drop below the THERM Limit minus
the programmable THERM Hysteresis (see Section 6.8, "Therm Hysteresis Register").
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Datasheet
5.6
System Configuration Controls
Each channel can be configured to use Resistance Error Correction, Beta Compensation, and Digital
Averaging based on user settings and system requirements. Conversion rates and Dynamic Averaging
are also configurable.
5.6.1
Resistance Error Correction
The EMC1438 includes active Resistance Error Correction to remove the effect of up to 100 ohms of
series resistance. Without this automatic feature, voltage developed across the parasitic resistance in
the remote diode path causes the temperature to read higher than the true temperature is. The error
induced by parasitic resistance is approximately +0.7°C per ohm. Sources of series resistance include
bulk resistance in the remote temperature transistor junctions, series resistance in the CPU, and
resistance in the printed circuit board traces and package leads. Resistance error correction in the
EMC1438 eliminates the need to characterize and compensate for parasitic resistance in the remote
diode path.
5.6.2
Beta Compensation
The forward current gain, or beta, of a transistor is not constant as emitter currents change. As well,
it is not constant over changes in temperature. The variation in beta causes an error in temperature
reading that is proportional to absolute temperature. Compensating for this error is also known as
implementing the BJT or transistor model for temperature measurement.
For discrete transistors configured with the collector and base shorted together, the beta is generally
sufficiently high such that the percent change in beta variation is very small. For example, a 10%
variation in beta for two forced emitter currents with a transistor whose ideal beta is 50 would contribute
approximately 0.25°C error at 100°C. However, for substrate transistors where the base-emitter
junction is used for temperature measurement and the collector is tied to the substrate, the proportional
beta variation will cause large error. For example, a 10% variation in beta for two forced emitter
currents with a transistor whose ideal beta is 0.5 would contribute approximately 8.25°C error at 100°C.
The Beta Compensation circuitry in the EMC1438 corrects for this beta variation to eliminate any error
which would normally be induced. It automatically detects the appropriate beta setting to use.
5.6.3
Digital Averaging
To reduce the effect of noise and temperature spikes on the reported temperature, all of the external
diode channels can use digital averaging. This averaging acts as a running average using the previous
four measured values.
The default setting is to have digital averaging disabled for all channels. It can be enabled for each
channel individually by the Filter Control Register (Section 6.22, "Filter Control Register").
5.6.4
Conversion Rates
The EMC1438 may be configured for different conversion rates based on the system requirements.
The conversion rate is configured as described in Section 6.5, "Conversion Rate Register". The default
conversion rate is 4 conversions per second. Other available conversion rates are shown in Table 6.7.
5.6.5
Dynamic Averaging
Dynamic averaging causes the EMC1438 to measure the external diode channels for an extended time
based on the selected conversion rate. This functionality can be disabled for increased power savings
at the lower conversion rates (see Section 6.4, "Configuration Register"). When dynamic averaging is
enabled, the device will automatically adjust the sampling and measurement time for the external diode
channels. This allows the device to average 2x or 4x longer than the normal 11 bit operation (nominally
21ms per channel) while still maintaining the selected conversion rate. The benefits of dynamic
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averaging are improved noise rejection due to the longer integration time as well as less random
variation of the temperature measurement.
When enabled, the dynamic averaging will affect the average supply current based on the chosen
conversion rate as shown in Table 5.1 for EMC1438.
Table 5.1 Supply Current vs. Conversion Rate for EMC1438
AVERAGING FACTOR (BASED ON
11-BIT OPERATION)
AVERAGE SUPPLY CURRENT
CONVERSION RATE
DYNAMIC
AVERAGING
ENABLED
(DEFAULT)
DYNAMIC
AVERAGING
DISABLED
DYNAMIC
AVERAGING
ENABLED
(DEFAULT)
DYNAMIC
AVERAGING
DISABLED
1 / sec
715uA
450uA
4x
1x
2 / sec
750uA
550uA
2x
1x
4 / sec (default)
900uA
815uA
1x
1x
Continuous (see Table 6.8)
950uA
950uA
0.5x
0.5x
5.7
Diode Connections
The diode connection for the External Diode 1 channel can support a discrete diode-connected
transistor (such as a 2N3904) or a substrate transistor (such as those found in a CPU or GPU). Antiparallel diodes are supported on all diode channels, except the External Diode 1 channel. Figure 5.2
shows examples of diode connections.
External
Diode 1
External
Diode 1
to DP1
External Diode Pair
y
x
to DP1
to DPx / DNy
to DN1
to DNy / DPx
to DN1
Local
Ground
Typical remote
substrate transistor
e.g. CPU substrate PNP
Typical remote
discrete NPN transistor
e.g. 2N3904
Anti-parallel diodes using
discrete NPN transistors
Figure 5.2 Diode Connections
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Datasheet
Chapter 6 Register Description
The registers shown in Table 6.1 are accessible through the SMBus. An entry of ‘-’ indicates that the
bit is not used and will always read ‘0’.
In some registers, the EMC1438-1 and EMC1438-2 have different defaults. Due to space limitations,
these are noted in the DEFAULT VALUE columns using “(-1)” for EMC1438-1 and “(-2)” for EMC14382.
Table 6.1 Register Set in Hexadecimal Order
REGISTER
ADDRESS
R/W
REGISTER NAME
FUNCTION
DEFAULT
VALUE
PAGE
00h
R
Internal Diode Data
High Byte
Stores the integer data for the
Internal Diode
00h
Page 28
01h
R
External Diode 1
Data High Byte
Stores the integer data for the
External Diode 1
00h
Page 28
02h
R-C
Status
Reports general error conditions
00h
Page 29
03h
R/W
Configuration
Controls the general operation of
the device (mirrored at address
09h)
80h
Page 30
04h
R/W
Conversion Rate
Controls the conversion rate for
updating temperature data
(mirrored at address 0Ah)
06h
(4/sec)
Page 31
05h
R/W
Internal Diode High
Limit
Stores the 8-bit high limit for the
Internal Diode (mirrored at address
0Bh)
55h
(85°C)
Page 31
06h
R/W
Internal Diode Low
Limit
Stores the 8-bit low limit for the
Internal Diode (mirrored at address
0Ch)
00h
(0°C)
Page 31
07h
R/W
External Diode 1
High Limit High Byte
Stores the integer portion of the
high limit for the External Diode 1
(mirrored at register 0Dh)
55h
(85°C)
Page 31
08h
R/W
External Diode 1 Low
Limit High Byte
Stores the integer portion of the
low limit for the External Diode 1
(mirrored at register 0Eh)
00h
(0°C)
Page 31
09h
R/W
Configuration
Controls the general operation of
the device (mirrored at address
03h)
80h
Page 30
0Ah
R/W
Conversion Rate
Controls the conversion rate for
updating temperature data
(mirrored at address 04h)
06h
(4/sec)
Page 31
0Bh
R/W
Internal Diode High
Limit
Stores the 8-bit high limit for the
Internal Diode (mirrored at address
05h)
55h
(85°C)
Page 31
0Ch
R/W
Internal Diode Low
Limit
Stores the 8-bit low limit for the
Internal Diode (mirrored at address
06h)
00h
(0°C)
Page 31
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Datasheet
Table 6.1 Register Set in Hexadecimal Order (continued)
REGISTER
ADDRESS
R/W
REGISTER NAME
FUNCTION
0Dh
R/W
External Diode 1
High Limit High Byte
Stores the integer portion of the
high limit for the External Diode 1
(mirrored at register 07h)
55h
(85°C)
Page 31
0Eh
R/W
External Diode 1 Low
Limit High Byte
Stores the integer portion of the
low limit for the External Diode 1
(mirrored at register 08h)
00h
(0°C)
Page 31
0Fh
W
One shot
A write to this register during
Standby initiates a one shot
update.
00h
Page 34
10h
R
External Diode 1
Data Low Byte
Stores the fractional data for the
External Diode 1
00h
Page 28
13h
R/W
External Diode 1
High Limit Low Byte
Stores the fractional portion of the
high limit for the External Diode 1
00h
Page 31
14h
R/W
External Diode 1 Low
Limit Low Byte
Stores the fractional portion of the
low limit for the External Diode 1
00h
Page 31
15h
R/W
External Diode 2
High Limit High Byte
Stores the integer portion of the
high limit for External Diode 2
55h
(85°C)
Page 31
16h
R/W
External Diode 2 Low
Limit High Byte
Stores the integer portion of the
low limit for External Diode 2
00h
(0°C)
Page 31
17h
R/W
External Diode 2
High Limit Low Byte
Stores the fractional portion of the
high limit External Diode 2
00h
Page 31
18h
R/W
External Diode 2 Low
Limit Low Byte
Stores the fractional portion of the
low limit for External Diode 2
00h
Page 31
19h
R/W
External Diode 1
THERM Limit
Stores the 8-bit critical temperature
limit for the External Diode 1
55h
(85°C)
Page 35
1Ah
R/W
External Diode 2
THERM Limit
Stores the 8-bit critical temperature
limit for External Diode 2
55h
(85°C)
Page 35
1Bh
R-C
External Diode Fault
Stores status bits indicating which
external diode detected a diode
fault
00h
Page 36
1Fh
R/W
Interrupt Mask
Register
Controls the masking of the
ALERT pin for individual channels
00h
Page 36
20h
R/W
Internal Diode
THERM Limit
Stores the 8-bit critical temperature
limit for the Internal Diode
55h
(85°C)
Page 35
21h
R/W
THERM Hysteresis
Stores the 8-bit hysteresis value
that applies to all THERM limits
0Ah
(10°C)
Page 35
22h
R/W
Consecutive ALERT
Controls the number of out-of-limit
conditions that must occur before
the status bit is asserted
70h
Page 37
23h
R
External Diode 2
Data High Byte
Stores the integer data for External
Diode 2
00h
Page 28
24h
R
External Diode 2
Data Low Byte
Stores the fractional data for
External Diode 2
00h
Page 28
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DATASHEET
DEFAULT
VALUE
PAGE
SMSC EMC1438
1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
Table 6.1 Register Set in Hexadecimal Order (continued)
REGISTER
ADDRESS
R/W
REGISTER NAME
FUNCTION
DEFAULT
VALUE
PAGE
25h
R/W
External Diode 1
Beta Configuration
Stores the Beta Compensation
circuitry settings for External Diode
1
08h
Page 38
26h
R/W
External Diode 2
Beta Configuration
Stores the Beta Compensation
circuitry settings for External Diode
2
08h
Page 38
29h
R
Internal Diode Data
Low Byte
Stores the fractional data for the
Internal Diode
00h
Page 28
2Ah
R
External Diode 3
High Byte
Stores the integer data for External
Diode 3
00h
Page 28
2Bh
R
External Diode 3 Low
Byte
Stores the fractional data for
External Diode 3
00h
Page 28
2Ch
R/W
External Diode 3
High Limit High Byte
Stores the integer portion of the
high limit for External Diode 3
55h
(85°C)
Page 31
2Dh
R/W
External Diode 3 Low
Limit High Byte
Stores the integer portion of the
low limit for External Diode 3
00h
(0°C)
Page 31
2Eh
R/W
External Diode 3
High Limit Low Byte
Stores the fractional portion of the
high limit for External Diode 3
00h
Page 31
2Fh
R/W
External Diode 3 Low
Limit Low Byte
Stores the fractional portion of the
low limit for External Diode 3
00h
Page 31
30h
R/W
External Diode 3
THERM Limit
Stores the 8-bit critical temperature
limit for External Diode 3
55h
(85°C)
Page 35
32h
R
Hottest Diode High
Byte
Stores the integer data for the
hottest temperature
80h
Page 39
33h
R
Hottest Diode Low
Byte
Stores the fractional data for the
hottest temperature
00h
Page 39
34h
R-C
Hottest Status
Status bits indicating which
external diode is hottest
00h
Page 39
35h
R-C
High Limit Status
Status bits for the High Limits
00h
Page 39
36h
R-C
Low Limit Status
Status bits for the Low Limits
00h
Page 40
37h
R
THERM Limit Status
Status bits for the THERM Limits
00h
Page 41
39h
R/W
REC Configuration
Controls REC for all channels
00h
Page 42
3Ah
R/W
Hottest Config
Controls which external diode
channels are used in the “hottest
of “comparison
00h
Page 42
3Bh
R/W
Channel Config
Controls which channels are
enabled
0Eh (-1)
00h (-2)
Page 42
40h
R/W
Filter Control
Controls the digital filter setting for
the External Diode 1 channel
00h
Page 43
41h
R
External Diode 4
Data High Byte
Stores the integer data for the
External Diode 4 channel
00h
Page 28
SMSC EMC1438
25
DATASHEET
Revision 1.0 (04-29-10)
1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
Table 6.1 Register Set in Hexadecimal Order (continued)
REGISTER
ADDRESS
R/W
REGISTER NAME
FUNCTION
DEFAULT
VALUE
PAGE
42h
R
External Diode 4
Data Low Byte
Stores the fractional data for the
External Diode 4 channel
00h
Page 28
43h
R
External Diode 5
Data High Byte
Stores the integer data for the
External Diode 5 channel
00h
Page 28
44h
R
External Diode 5
Data Low Byte
Stores the fractional data for the
External Diode 5 channel
00h
Page 28
45h
R
External Diode 6
Data High Byte
Stores the integer data for the
External Diode 6 channel
00h
Page 28
46h
R
External Diode 6
Data Low Byte
Stores the fractional data for the
External Diode 6 channel
00h
Page 28
47h
R
External Diode 7
Data High Byte
Stores the integer data for the
External Diode 7 channel
00h
Page 28
48h
R
External Diode 7
Data Low Byte
Stores the fractional data for the
External Diode 7 channel
00h
Page 28
50h
R/W
External Diode 4
High Limit High Byte
Stores the integer data for the high
limit for the External Diode 4
channel
55h
(85°C)
Page 31
51h
R/W
External Diode 4 Low
Limit High Byte
Stores the integer data for the low
limit for the External Diode 4
channel
00h
(0°C)
Page 31
52h
R/W
External Diode 4
HIgh Limit Low Byte
Stores the fractional data for the
low limit for the External Diode 4
channel
00h
Page 31
53h
R/W
External Diode 4 Low
Limit Low Byte
Stores the fractional data for the
low limit for the External Diode 4
channel
00h
Page 31
54h
R/W
External Diode 5
High Limit High Byte
Stores the integer data for the high
limit for the External Diode 5
channel
55h
(85°C)
Page 31
55h
R/W
External Diode 5 Low
Limit High Byte
Stores the integer data for the low
limit for the External Diode 5
channel
00h
(0°C)
Page 31
56h
R/W
External Diode 5
HIgh Limit Low Byte
Stores the fractional data for the
low limit for the External Diode 5
channel
00h
Page 31
57h
R/W
External Diode 5 Low
Limit Low Byte
Stores the fractional data for the
low limit for the External Diode 5
channel
00h
Page 31
58h
R/W
External Diode 6
High Limit High Byte
Stores the integer data for the high
limit for the External Diode 6
channel
55h
(85°C)
Page 31
59h
R/W
External Diode 6 Low
Limit High Byte
Stores the integer data for the low
limit for the External Diode 6
channel
00h
(0°C)
Page 31
Revision 1.0 (04-29-10)
26
DATASHEET
SMSC EMC1438
1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
Table 6.1 Register Set in Hexadecimal Order (continued)
REGISTER
ADDRESS
R/W
REGISTER NAME
FUNCTION
5Ah
R/W
External Diode 6
HIgh Limit Low Byte
Stores the fractional data for the
low limit for the External Diode 6
channel
00h
(0°C)
Page 31
5Bh
R/W
External Diode 6 Low
Limit Low Byte
Stores the fractional data for the
low limit for the External Diode 6
channel
00h
(0°C)
Page 31
5Ch
R/W
External Diode 7
High Limit High Byte
Stores the integer data for the high
limit for the External Diode 7
channel
55h
(85°C)
Page 31
5Dh
R/W
External Diode 7 Low
Limit High Byte
Stores the integer data for the low
limit for the External Diode 7
channel
00h
(0°C)
Page 31
5Eh
R/W
External Diode 7
HIgh Limit Low Byte
Stores the fractional data for the
low limit for the External Diode 7
channel
00h
Page 31
5Fh
R/W
External Diode 7 Low
Limit Low Byte
Stores the fractional data for the
low limit for the External Diode 7
channel
00h
Page 31
64h
R/W
External Diode 4
THERM Limit
Stores the 8-bit critical temperature
limit for External Diode 4
55h
(85°C)
Page 31
65h
R/W
External Diode 5
THERM Limit
Stores the 8-bit critical temperature
limit for External Diode 5
55h
(85°C)
Page 31
66h
R/W
External Diode 6
THERM Limit
Stores the 8-bit critical temperature
limit for External Diode 6
55h
(85°C)
Page 31
67h
R/W
External Diode 7
THERM Limit
Stores the 8-bit critical temperature
limit for External Diode 7
55h
(85°C)
Page 31
71h
R/W
External Diode 4
Beta Configuration
Stores the Beta Compensation
circuitry settings for External Diode
4
08h
Page 38
72h
R/W
External Diode 6
Beta Configuration
Stores the Beta Compensation
circuitry settings for External Diode
6
08h
Page 38
FDh
R
Product ID
Stores a fixed value that identifies
each product
59h
Page 44
FEh
R
Manufacturer ID
Stores a fixed value that
represents SMSC
5Dh
Page 44
FFh
R
Revision
Stores a fixed value that
represents the revision number
00h
Page 44
SMSC EMC1438
27
DATASHEET
DEFAULT
VALUE
PAGE
Revision 1.0 (04-29-10)
1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
6.1
Data Read Interlock
When any temperature channel high byte register is read, the corresponding low byte is copied into
an internal ‘shadow’ register. The user is free to read the low byte at any time and be guaranteed that
it will correspond to the previously read high byte. Regardless if the low byte is read or not, reading
from the same high byte register again will automatically refresh this stored low byte data.
6.2
Temperature Data Registers
Table 6.2 Temperature Data Registers
ADDR
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
00h
R
Internal Diode
High Byte
Sign
64
32
16
8
4
2
1
00h
29h
R
Internal Diode
Low Byte
0.5
0.25
0.125
-
-
-
-
-
00h
01h
R
External Diode
1 High Byte
Sign
64
32
16
8
4
2
1
00h
10h
R
External Diode
1 Low Byte
0.5
0.25
0.125
-
-
-
-
-
00h
23h
R
External Diode
2 High Byte
Sign
64
32
16
8
4
2
1
00h
24h
R
External Diode
2 Low Byte
0.5
0.25
0.125
-
-
-
-
-
00h
2Ah
R
External Diode
3 High Byte
Sign
64
32
16
8
4
2
1
00h
2Bh
R
External Diode
3 Low Byte
0.5
0.25
0.125
-
-
-
-
-
00h
41h
R
External Diode
4 High Byte
Sign
64
32
16
8
4
2
1
00h
42h
R
External Diode
4 Low Byte
0.5
0.25
0.125
-
-
-
-
-
00h
43h
R
External Diode
5 High Byte
Sign
64
32
16
8
4
2
1
00h
44h
R
External Diode
5 Low Byte
0.5
0.25
0.125
-
-
-
-
-
00h
45h
R
External Diode
6 High Byte
Sign
64
32
16
8
4
2
1
00h
46h
R
External Diode
6 Low Byte
0.5
0.25
0.125
-
-
-
-
-
00h
47h
R
External Diode
7 High Byte
Sign
64
32
16
8
4
2
1
00h
48h
R
External Diode
7 Low Byte
0.5
0.25
0.125
-
-
-
-
-
00h
Revision 1.0 (04-29-10)
28
DATASHEET
SMSC EMC1438
1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
All temperatures are stored as an 11-bit value with the high byte representing the integer value and
the low byte representing the fractional value left justified to occupy the MSBits. The data format is
standard 2’s complement from -64°C to 127.875°C as shown in Table 6.3.
Table 6.3 Temperature Data Format
BINARY
HEX (AS READ BY
REGISTERS)
Diode Fault
1000_0000_000b
80_00h
-64
1100_0000_000b
C0_00h
-63.875
1100_0000_001b
C0_20h
-1
1111_1111_000b
FF_00h
-0.125
1111_1111_111b
FF_E0h
0
0000_0000_000b
00_00h
0.125
0000_0000_001b
00_20h
1
0000_0001_000b
01_00h
63
0011_1111_000b
3F_00h
64
0100_0000_000b
40_00h
127
0111_1111_000b
7F_00h
127.875
0111_1111_111b
7F_E0h
TEMPERATURE (°C)
6.3
Status Register
Table 6.4 Status Register
ADDR
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
02h
R
Status
BUSY
HOTTEST
-
HIGH
LOW
FAULT
THERM
-
00h
The Status Register reports general error conditions (see Section 5.3.1, "Status").
Bit 7 - BUSY - This bit indicates that the ADC is currently converting. This bit does not cause the
ALERT pin to be asserted. This bit is set and cleared by the device.
Bit 6 - HOTTEST - This bit is set if the REM_HOT bit is set and the hottest channel changes (see
Section 5.3.3, "“Hottest Of” Comparison"). This bit is cleared when this register is read.
Bit 4 - HIGH - This bit is set when any one of the temperature channels meets or exceeds its
programmable high limit criteria (see Section 5.3.2, "Limits and Fault Queues"). If the ALERT pin is in
interrupt mode, reading from the High Limit Status Register will clear this bit if the error condition has
been removed. If the ALERT pin is in comparator mode, this bit is cleared when the ALERT pin is
deasserted (see Section 5.4.2, "ALERT Pin Comparator Mode").
Bit 3 - LOW - This bit is set when any one of the temperature channels drops below its programmed
low limit criteria (see Section 5.3.2, "Limits and Fault Queues"). Reading from the Low Limit Status
Register will clear this bit if the error condition has been removed.
SMSC EMC1438
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Revision 1.0 (04-29-10)
1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
Bit 2 - FAULT - This bit is asserted when a diode fault is detected on any one of the external diode
channels (see Section 5.3.4, "Diode Faults"). Reading from the External Diode Fault Register will clear
this bit if the error condition has been removed.
Bit 1 - THERM - This bit is set when any one of the external diode channels meets or exceeds its
THERM limit criteria (see Section 5.3.2, "Limits and Fault Queues").
6.4
Configuration Register
Table 6.5 Configuration Register
ADDR
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
03h
R/W
Config
MASK_
ALL
STANDBY
ALERT/
COMP
-
-
-
DAVG_
DIS
-
80h
09h
The Configuration Register controls the basic operation of the device. This register is fully accessible
at either address.
Bit 7 - MASK_ALL - Masks the ALERT pin from asserting.
„
‘0’ - The ALERT pin is not masked. If any of the appropriate status bits are set, the ALERT pin will
be asserted.
„
‘1’ (default) - The ALERT pin is masked. It will not be asserted for any interrupt condition, although
it may be asserted if the ALERT pin is configured to operate in comparator mode (see Section
5.4.2, "ALERT Pin Comparator Mode"). The Status Registers will be updated normally.
Bit 6 - STANDBY - Enables the Standby state without using the STANDBY pin (see Section 5.2, "Power
States").
Note: The STANDBY pin has no effect on this bit. If asserted, it will not set this bit to ‘1’.
„
‘0’ (default) - The EMC1438 is in the Active state if the STANDBY pin is not asserted.
„
‘1’ - The EMC1438 is in the Standby state.
Bit 5 - ALERT/COMP - Controls the operation of the ALERT pin.
„
‘0’ (default) - The ALERT pin acts in interrupt mode as described in Section 5.4.1.
„
‘1’ - The ALERT pin acts in comparator mode as described in Section 5.4.2. In this mode the
MASK_ALL bit is ignored.
Bit 1 - DAVG_DIS - Disables the dynamic averaging feature on all temperature channels (see Section
5.6.5, "Dynamic Averaging").
„
‘0’ (default) - The dynamic averaging feature is enabled. All temperature channels will be converted
with an averaging factor that is based on the conversion rate as shown in Table 5.1.
„
‘1’ - The dynamic averaging feature is disabled. All temperature channels will be converted with a
maximum averaging factor of 1x (equivalent to 11-bit conversion). For higher conversion rates (i.e.
more conversions per second), this averaging factor will be reduced as shown in Table 5.1.
Revision 1.0 (04-29-10)
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SMSC EMC1438
1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
6.5
Conversion Rate Register
Table 6.6 Conversion Rate Register
ADDR
R/W
REGISTER
B7
B6
B5
B4
04h
R/W
Conversion
Rate
-
-
-
-
0Ah
B3
B2
B1
B0
CONV[2:0]
DEFAULT
06h
(4/sec)
The Conversion Rate Register controls how often the temperature measurement channels are updated
and compared against the limits. This register is fully accessible at either register address.
Bits 3-0 - CONV[3:0] - Determines the conversion rate as shown in Table 6.7.
Table 6.7 Conversion Rate
CONV[2:0]
2
1
0
CONVERSIONS / SECOND
1
0
0
1
1
0
1
2
1
1
0
4 (default)
1
1
1
Continuous
All Others
4
The actual conversion rate for Continuous conversions will depend on the number of diode channels
enabled and is shown in Table 6.8.
Table 6.8 Maximum Conversion Rate Per Temperature Channels
NUMBER OF EXTERNAL DIODE CHANNELS
MAX CONVERSION RATE
4
15 / sec
5
13 / sec
6
11 / sec
7
10 / sec
6.6
Temperature Limit Registers
Table 6.9 Temperature Limit Registers
ADDR.
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
05h
R/W
Internal Diode
High Limit
Sign
64
32
16
8
4
2
1
55h
(85°C)
0Bh
SMSC EMC1438
31
DATASHEET
Revision 1.0 (04-29-10)
1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
Table 6.9 Temperature Limit Registers (continued)
ADDR.
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
06h
R/W
Internal Diode
Low Limit
Sign
64
32
16
8
4
2
1
00h
(0°C)
R/W
External
Diode 1 High
Limit High
Byte
Sign
64
32
16
8
4
2
1
55h
(85°C)
13h
R/W
External
Diode 1 High
Limit Low
Byte
0.5
0.25
0.125
-
-
-
-
-
00h
08h
R/W
External
Diode 1 Low
Limit High
Byte
Sign
64
32
16
8
4
2
1
00h
(0°C)
14h
R/W
External
Diode 1 Low
Limit Low
Byte
0.5
0.25
0.125
-
-
-
-
-
00h
15h
R/W
External
Diode 2 High
Limit High
Byte
Sign
64
32
16
8
4
2
1
55h
(85°C)
16h
R/W
External
Diode 2 Low
Limit High
Byte
Sign
64
32
16
8
4
2
1
00h
(0°C)
17h
R/W
External
Diode 2 High
Limit Low
Byte
0.5
0.25
0.125
-
-
-
-
-
00h
18h
R/W
External
Diode 2 Low
Limit Low
Byte
0.5
0.25
0.125
-
-
-
-
-
00h
2Ch
R/W
External
Diode 3 High
Limit High
Byte
Sign
64
32
16
8
4
2
1
55h
(85°C)
2Dh
R/W
External
Diode 3 Low
Limit High
Byte
Sign
64
32
16
8
4
2
1
00h
(0°C)
2Eh
R/W
External
Diode 3 High
Limit Low
Byte
0.5
0.25
0.125
-
-
-
-
-
00h
0Ch
07h
0Dh
0Eh
Revision 1.0 (04-29-10)
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DATASHEET
SMSC EMC1438
1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
Table 6.9 Temperature Limit Registers (continued)
ADDR.
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
2Fh
R/W
External
Diode 3 Low
Limit Low
Byte
0.5
0.25
0.125
-
-
-
-
-
00h
50h
R/W
External
Diode 4 High
Limit High
Byte
Sign
64
32
16
8
4
2
1
55h
(85°C)
51h
R/W
External
Diode 4 Low
Limit High
Byte
Sign
64
32
16
8
4
2
1
00h
(0°C)
52h
R/W
External
Diode 4 High
Limit Low
Byte
0.5
0.25
0.125
-
-
-
-
-
00h
53h
R/W
External
Diode 4 Low
Limit Low
Byte
0.5
0.25
0.125
-
-
-
-
-
00h
54h
R/W
External
Diode 5 High
Limit High
Byte
Sign
64
32
16
8
4
2
1
55h
(85°C)
55h
R/W
External
Diode 5 Low
Limit High
Byte
Sign
64
32
16
8
4
2
1
00h
(0°C)
56h
R/W
External
Diode 5 High
Limit Low
Byte
0.5
0.25
0.125
-
-
-
-
-
00h
57h
R/W
External
Diode 5 Low
Limit Low
Byte
0.5
0.25
0.125
-
-
-
-
-
00h
58h
R/W
External
Diode 6 High
Limit High
Byte
Sign
64
32
16
8
4
2
1
55h
(85°C)
59h
R/W
External
Diode 6 Low
Limit High
Byte
Sign
64
32
16
8
4
2
1
00h
(0°C)
5Ah
R/W
External
Diode 6 High
Limit Low
Byte
0.5
0.25
0.125
-
-
-
-
-
00h
SMSC EMC1438
33
DATASHEET
Revision 1.0 (04-29-10)
1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
Table 6.9 Temperature Limit Registers (continued)
ADDR.
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
5Bh
R/W
External
Diode 6 Low
Limit Low
Byte
0.5
0.25
0.125
-
-
-
-
-
00h
5Ch
R/W
External
Diode 7 High
Limit High
Byte
Sign
64
32
16
8
4
2
1
55h
(85°C)
5Dh
R/W
External
Diode 7 Low
Limit High
Byte
Sign
64
32
16
8
4
2
1
00h
(0°C)
5Eh
R/W
External
Diode 7 High
Limit Low
Byte
0.5
0.25
0.125
-
-
-
-
-
00h
5Fh
R/W
External
Diode 7 Low
Limit Low
Byte
0.5
0.25
0.125
-
-
-
-
-
00h
The device contains both high and low limits for all temperature channels. If the measured temperature
meets or exceeds the high limit, the corresponding status bits are set (see Section 5.3.1, "Status") and
the ALERT pin may be asserted (see Section 5.4, "ALERT Output"). Likewise, if the measured
temperature is less than the low limit, the corresponding status bits are set and the ALERT pin may
be asserted.
The limit registers with multiple register addresses are fully accessible at either address.
When the device is in the Standby state, updating the limit registers will have no effect until the next
conversion cycle occurs. This can be initiated via a write to the One Shot Register (see Section 6.7,
"One Shot Register").
6.7
One Shot Register
Table 6.10 One Shot Register
ADDR.
R/W
REGISTER
0Fh
W
One Shot
B7
B6
B5
B4
B3
B2
B1
B0
Writing to this register in Standby initiates a single conversion
cycle. Data is not stored and always reads 00h
DEFAULT
00h
The One Shot Register is used to initiate a one shot command. Writing to the one shot register, when
the device is in the Standby state (see Section 5.2, "Power States") and the BUSY bit (see Section
6.3, "Status Register") is ‘0’, will immediately cause the ADC to update all temperature measurements.
Writing to the One Shot Register while the device is in the Active state will have no effect.
Revision 1.0 (04-29-10)
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DATASHEET
SMSC EMC1438
1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
6.8
Therm Hysteresis Register
Table 6.11 Therm Hysteresis Register
ADDR.
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
21h
R/W
THERM
Hysteresis
-
64
32
16
8
4
2
1
0Ah
(10°C)
The THERM Hysteresis is used in conjunction with the THERM Limit Registers to set the THERM
status bits (see Section 5.5, "THERM Output"). In addition, the THERM Hysteresis Register is used
with the High Limit Registers when the ALERT pin is configured to act as a comparator (see Section
5.4.2, "ALERT Pin Comparator Mode").
6.9
Therm Limit Registers
Table 6.12 Therm Limit Registers
ADDR.
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
19h
R/W
External
Diode 1
THERM Limit
Sign
64
32
16
8
4
2
1
55h
(85°C)
1Ah
R/W
External
Diode 2
THERM Limit
Sign
64
32
16
8
4
2
1
55h
(85°C)
20h
R/W
Internal Diode
THERM Limit
Sign
64
32
16
8
4
2
1
55h
(85°C)
30h
R/W
External
Diode 3
THERM Limit
Sign
64
32
16
8
4
2
1
55h
(85°C)
64h
R/W
External
Diode 4
THERM Limit
Sign
64
32
16
8
4
2
1
55h
(85°C)
65h
R/W
External
Diode 5
THERM Limit
Sign
64
32
16
8
4
2
1
55h
(85°C)
66h
R/W
External
Diode 6
THERM Limit
Sign
64
32
16
8
4
2
1
55h
(85°C)
67h
R/W
External
Diode 7
THERM Limit
Sign
64
32
16
8
4
2
1
55h
(85°C)
The THERM Limit Registers are used to set the THERM status bits and assert the THERM pin (see
Section 5.5, "THERM Output").
SMSC EMC1438
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DATASHEET
Revision 1.0 (04-29-10)
1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
6.10
External Diode Fault Register
Table 6.13 External Diode Fault Register
ADDR
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
1Bh
R-C
External
Diode Fault
E7FLT
E6FLT
E5FLT
E4FLT
E3FLT
E2FLT
E1FLT
-
00h
The External Diode Fault Register contains the status bits that are set when a temperature channel
meets the diode fault criteria (see Section 5.3.4, "Diode Faults"). If any of these bits are set, the FAULT
status bit in the Status Register is set. Reading from the External Diode Fault Register will clear all
bits if the error condition has been removed. Reading from the register will also clear the FAULT status
bit in the Status Register.
The ALERT pin, if configured in interrupt mode, may be set if any of these status bits are set (see
Section 5.4, "ALERT Output").
Bit 7 - E7FLT - This bit is set if the External Diode 7 channel reported a diode fault.
Bit 6 - E6FLT - This bit is set if the External Diode 6 channel reported a diode fault.
Bit 5 - E5FLT - This bit is set if the External Diode 5 channel reported a diode fault.
Bit 4 - E4FLT - This bit is set if the External Diode 4 channel reported a diode fault.
Bit 3 - E3FLT - This bit is set if the External Diode 3 channel reported a diode fault.
Bit 2 - E2FLT - This bit is set if the External Diode 2 channel reported a diode fault.
Bit 1 - E1FLT - This bit is set if the External Diode 1 channel reported a diode fault.
6.11
Channel Interrupt Mask Register
Table 6.14 Channel Interrupt Mask Register
ADDR
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
1Fh
R/W
Channel
Mask
E7_
MSK
E6_
MSK
E5_
MSK
E4_
MSK
E3_
MSK
E2_
MSK
E1_
MSK
INT_
MSK
00h
The Channel Interrupt Mask Register controls individual channel masking. When a channel is masked,
the ALERT pin will not be asserted when the masked channel reads a diode fault or out of limit error.
Bits 7-1 - Ex_MSK - Prevents the ALERT pin from being asserted when the External Diode X channel
is out of limit or reports a diode fault. If the EXT6_APD bit is not set (see Section 6.21, "Channel
Configuration Register"), the EXT7_MSK bit is ignored. Likewise, if the EXT4_APD bit is not set, then
the EXT5_MSK bit is ignored, and if the EXT2_APD bit is not set (see Section 6.21), the EXT3_MSK
bit is ignored.
„
‘0’ (default) - The External Diode X channel will cause the ALERT pin to be asserted if it is out of
limit or reports a diode fault.
„
‘1’ - The External Diode X channel will not cause the ALERT pin to be asserted if it is out of limit
or reports a diode fault.
Bit 0 - INT_MSK - Prevents the ALERT pin from being asserted when the Internal Diode temperature
is out of limit.
„
‘0’ (default) - The Internal Diode channel will cause the ALERT pin to be asserted if it is out of limit.
Revision 1.0 (04-29-10)
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DATASHEET
SMSC EMC1438
1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
„
6.12
‘1’ - The Internal Diode channel will not cause the ALERT pin to be asserted if it is out of limit.
Consecutive ALERT Register
Table 6.15 Consecutive ALERT Register
ADDR
R/W
REGISTER
B7
22h
R/W
Consecutive
ALERT
TIME
OUT
B6
B5
B4
B3
CTHERM[2:0]
B2
B1
CALRT[2:0]
B0
DEFAULT
-
70h
The Consecutive ALERT Register determines how many times an out-of-limit error or diode fault must
be detected in consecutive measurements before the status registers are asserted (see Section 5.3.2,
"Limits and Fault Queues").
Bit 7 - TIMEOUT - Determines whether the SMBus Timeout function is enabled.
„
‘0’ (default) - The SMBus Timeout and idle timeout features are disabled. The SMCLK line can be
held low indefinitely without the device resetting its SMBus protocol.
„
‘1’ - The SMBus Timeout feature is enabled. If the SMCLK line is held low for more than 30ms,
the device will reset the SMBus protocol. The Idle Timeout is also enabled. If both the SMCLK and
SMDATA lines are held high for longer than 150us, the device will reset the SMBus protocol.
Bits 6-4 CTHERM[2:0] - Determines the number of consecutive measurements that must exceed the
corresponding THERM Limit before the corresponding THERM Limit status bit is set and the THERM
pin is asserted (if enabled for the channel). All temperature channels use this value to set the
respective counters.
The bits are decoded as shown in Table 6.16. The default setting is 4 consecutive out of limit
conversions.
Bits 3-1 - CALRT[2:0] - Determine the number of consecutive measurements that must have an out of
limit condition or diode fault before the applicable status bits are asserted. All temperature channels
use this value to set the respective counters. The bits are decoded as shown in Table 6.16. The default
setting is 1 consecutive out-of-limit conversion or diode fault.
APPLICATION NOTE: If one of the fault queues is not cleared and the CALRT[2:0] or CTHERM[2:0] bits are
updated, the update won’t take effect until the fault queue is cleared. All the fault queues are
independent so those that are empty will be updated immediately.
APPLICATION NOTE: If the ALERT pin is configured in comparator mode, these bits are ignored for low
temperature out-of-limit and diode faults. The value used is one occurrence.
Table 6.16 Consecutive Alert Settings
2
1
0
NUMBER OF CONSECUTIVE OUT OF LIMIT
MEASUREMENTS / DIODE FAULTS
0
0
0
1 (default for CALRT[2:0])
0
0
1
2
0
1
1
3
1
1
1
4 (default for CTHERM[2:0])
All Others
SMSC EMC1438
1 (CALRT[2:0]),
4 (CTHERM[2:0])
37
DATASHEET
Revision 1.0 (04-29-10)
1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
6.13
Beta Configuration Register
Table 6.17 Beta Configuration Register
ADDR.
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
25h
R/W
External Diode 1
Beta Configuration
-
-
-
-
AUTO1
BETA1[2:0]
08h
26h
R/W
External Diode 2
Beta Configuration
-
-
-
-
AUTO2
BETA2[2:0]
08h
71h
R/W
External Diode 4
Beta Configuration
-
-
-
-
AUTO4
BETA4[2:0]
08h
72h
R/W
External Diode 6
Beta Configuration
-
-
-
-
AUTO6
BETA6[2:0]
08h
These registers are used to set the Beta Compensation factor that is used for the External Diode
channels.
Bit 3 - AUTOx - Enables the Beta Compensation factor autodetection function.
„
‘0’ - The Beta Compensation Factor autodetection circuitry is disabled. The External Diode will
always use the Beta Compensation factor set by the BETAx[2:0] bits.
„
‘1’ (default) - The Beta Compensation factor autodetection circuitry is enabled. At the beginning of
every conversion, the optimal Beta Compensation factor setting will be determined and applied.
The BETAx[2:0] bits will be automatically updated to indicate the current setting.
Bit 2-0 - BETAx[2:0] - These bits always reflect the current beta configuration settings. These bits will
be updated automatically and writing to these bits will have no effect.
Table 6.18 Beta Compensation Look Up Table
BETAX[2:0]
2
1
0
MINIMUM BETA
0
0
0
< 0.08
0
0
1
< 0.111
0
1
0
< 0.176
0
1
1
< 0.29
1
0
0
< 0.48
1
0
1
< 0.9
1
1
0
< 2.33
1
1
1
Disabled
Revision 1.0 (04-29-10)
38
DATASHEET
SMSC EMC1438
1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
6.14
Hottest Temperature Registers
Table 6.19 Hottest Temperature Registers
ADDR
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
32h
R
Hottest
Temperature
High Byte
Sign
64
32
16
8
4
2
1
80h
33h
R
Hottest
Temperature
Low Byte
0.5
0.25
0.125
-
-
-
-
-
00h
The Hottest Temperature Registers store the measured hottest temperature of all the selected external
diode channels (see Section 5.3.3, "“Hottest Of” Comparison"). If no External diodes are selected, the
High Byte Register will read 80h. The data format is the same as the temperature channels.
6.15
Hottest Temperature Status Register
Table 6.20 Hottest Temperature Register
ADDR
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
34h
R
Hottest
Temperature
Status
EXT7
EXT6
EXT5
EXT4
EXT3
EXT2
EXT1
INT
00h
The Hottest Temperature Status Register flags which external diode temperature is hottest (see
Section 5.3.3, "“Hottest Of” Comparison").
Bit 7 - EXT7 - The External Diode 7 channel is the hottest.
Bit 6 - EXT6 - The External Diode 6 channel is the hottest.
Bit 4 - EXT5 - The External Diode 5 channel is the hottest.
Bit 3 - EXT4 - The External Diode 4 channel is the hottest.
Bit 3 - EXT3 - The External Diode 3 channel is the hottest.
Bit 2 - EXT2 - The External Diode 2 channel is the hottest.
Bit 1 - EXT1 - The External Diode 1 channel is the hottest.
Bit 0 - INT - The Internal Diode channel is the hottest.
6.16
High Limit Status Register
Table 6.21 High Limit Status Register
ADDR
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
35h
R-C
High Limit
Status
E7
HIGH
E6
HIGH
E5
HIGH
E4
HIGH
E3
HIGH
E2
HIGH
E1
HIGH
I
HIGH
00h
SMSC EMC1438
39
DATASHEET
Revision 1.0 (04-29-10)
1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
The High Limit Status Register contains the status bits that are set when a temperature channel meets
the high limit criteria (see Section 5.3.2, "Limits and Fault Queues"). If any of these bits are set, the
HIGH status bit in the Status Register is set. If the ALERT pin is in interrupt mode, reading from the
High Limit Status Register will clear all bits if the error condition has been removed, and reading from
the register will also clear the HIGH status bit in the Status Register. If the ALERT pin is in comparator
mode, these bits are cleared when the ALERT pin is deasserted (see Section 5.4.2, "ALERT Pin
Comparator Mode").
The ALERT pin may be set if any of these status bits are set (see Section 5.4, "ALERT Output").
Bit 7 - E7HIGH - This bit is set when the External Diode 7 channel meets or exceeds its programmed
high limit.
Bit 6 - E6HIGH - This bit is set when the External Diode 6 channel meets or exceeds its programmed
high limit.
Bit 5 - E5HIGH - This bit is set when the External Diode 5 channel meets or exceeds its programmed
high limit.
Bit 4 - E4HIGH - This bit is set when the External Diode 4 channel meets or exceeds its programmed
high limit.
Bit 3 - E3HIGH - This bit is set when the External Diode 3 channel meets or exceeds its programmed
high limit.
Bit 2 - E2HIGH - This bit is set when the External Diode 2 channel meets or exceeds its programmed
high limit.
Bit 1 - E1HIGH - This bit is set when the External Diode 1 channel meets or exceeds its programmed
high limit.
Bit 0 - IHIGH - This bit is set when the Internal Diode channel meets or exceeds its programmed high
limit.
6.17
Low Limit Status Register
Table 6.22 Low Limit Status Register
ADDR.
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
36h
R-C
Low Limit
Status
E7
LOW
E6
LOW
E5
LOW
E4
LOW
E3
LOW
E2
LOW
E1
LOW
ILOW
00h
The Low Limit Status Register contains the status bits that are set when a temperature channel meets
the low limit criteria (see Section 5.3.2, "Limits and Fault Queues"). If any of these bits are set, the
LOW status bit in the Status Register is set. Reading from the Low Limit Status Register will clear all
bits if the error condition has been removed. Reading from the register will also clear the LOW status
bit in the Status Register.
The ALERT pin, if configured in interrupt mode, may be set if any of these status bits are set (see
Section 5.4, "ALERT Output").
Bit 7 - E7LOW - This bit is set when the External Diode 7 channel drops below its programmed low
limit.
Bit 6 - E6LOW - This bit is set when the External Diode 6 channel drops below its programmed low
limit.
Bit 5 - E5LOW - This bit is set when the External Diode 5 channel drops below its programmed low
limit.
Revision 1.0 (04-29-10)
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DATASHEET
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1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
Bit 4 - E4LOW - This bit is set when the External Diode 4 channel drops below its programmed low
limit.
Bit 3 - E3LOW - This bit is set when the External Diode 3 channel drops below its programmed low
limit.
Bit 2 - E2LOW - This bit is set when the External Diode 2 channel drops below its programmed low
limit.
Bit 1 - E1LOW - This bit is set when the External Diode 1 channel drops below its programmed low
limit.
Bit 0 - ILOW - This bit is set when the Internal Diode channel drops below its programmed low limit.
6.18
THERM Limit Status Register
Table 6.23 THERM Limit Status Register
ADDR
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
37h
R-C
THERM
Limit Status
E7
THERM
E6
THERM
E5
THERM
E4
THERM
E3
THERM
E2
THERM
E1
THERM
I
THERM
00h
The THERM Limit Status Register contains the status bits that are set when a temperature channel
meets the THERM Limit criteria (see Section 5.3.2, "Limits and Fault Queues"). If any of these bits are
set, the THERM status bit in the Status Register is set. Reading from the THERM Limit Status Register
will not clear the status bits. Once the temperature drops below the THERM Limit minus the THERM
Hysteresis, the corresponding status bits will be automatically cleared. The THERM bit in the Status
Register will be cleared when all individual channel THERM bits are cleared.
Bit 7 - E7THERM - This bit is set when the External Diode 7 channel meets or exceeds its programmed
THERM Limit.
Bit 6 - E6THERM - This bit is set when the External Diode 6 channel meets or exceeds its programmed
THERM Limit.
Bit 5 - E5THERM - This bit is set when the External Diode 5 channel meets or exceeds its programmed
THERM Limit.
Bit 4 - E4THERM - This bit is set when the External Diode 4 channel meets or exceeds its programmed
THERM Limit.
Bit 3 - E3THERM - This bit is set when the External Diode 3 channel meets or exceeds its programmed
THERM Limit.
Bit 2 - E2THERM - This bit is set when the External Diode 2 channel meets or exceeds its programmed
THERM Limit.
Bit 1 - E1THERM - This bit is set when the External Diode 1 channel meets or exceeds its programmed
THERM limit.
Bit 0 - ITHERM - This bit is set when the Internal Diode channel meets or exceeds its programmed
THERM limit.
SMSC EMC1438
41
DATASHEET
Revision 1.0 (04-29-10)
1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
6.19
REC Configuration Register
Table 6.24 REC Configuration Register
ADDR
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
39h
R/W
REC Config
E7
REC_n
E6_
REC_n
E5_
REC_n
E4_
REC_n
E3_
REC_n
E2_
REC_n
E1_
REC_n
-
00h
The REC Control Register controls the Resistance Error Correction circuitry for each of the external
diode channels.
Bits 7 - 0 - EX_REC_n - Disables the Resistance Error Correction (REC) for the External Diode X
channel.
6.20
„
‘0’ (default) - REC is enabled.
„
‘1’ - REC is disabled.
Hottest Configuration Register
Table 6.25 Hottest Configuration Register
ADDR
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
3Ah
R/W
Hottest
Config
E7HOT
E6HOT
E5HOT
E4HOT
E3HOT
E2HOT
E1HOT
IHOT
00h
The Hottest Configuration Register determines which External Diode Channels (if any) are compared
during the “Hottest Of” comparison that is automatically performed at the end of every conversion cycle
(see Section 5.3.3, "“Hottest Of” Comparison").
Bits 7 - 0 - ExHOT - Controls whether the External Diode X temperature data is compared during the
“Hottest Of” comparison.
„
‘0’ (default) - The External Diode X channel is not compared during the “Hottest Of” Comparison.
„
‘1’ - The External Diode X channel temperature data is compared to all other indicated channels
during the “Hottest Of” Comparison.
Bit 0 - IHOT - Controls whether the Internal Diode temperature data is compared during the “Hottest
Of” comparison.
6.21
„
‘0’ (default) - The Internal Diode channel is not compared during the “Hottest Of” Comparison.
„
‘1’ - The Internal Diode channel temperature data is compared to all other indicated channels during
the “Hottest Of” Comparison.
Channel Configuration Register
Table 6.26 Channel Configuration Register
ADDR
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
3Bh
R/W
Channel
Config
REM_
HOT
-
-
-
EXT6_
APD
EXT4_
APD
EXT2_
APD
-
0Eh (-1)
00h (-2)
Revision 1.0 (04-29-10)
42
DATASHEET
SMSC EMC1438
1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
The Channel Configuration Register determines which external diode channels are active in the device.
Bit 7 - REM_HOT - Enables circuitry that will remember the last temperature channel that was
determined to be the Hottest and flag an error if the hottest temperature channel changes (see Section
5.3.3, "“Hottest Of” Comparison").
„
‘0’ (default) - The HOTTEST status bit will not be asserted if the hottest temperature channel
changes.
„
‘1’ - If the hottest temperature channel changes, the HOTTEST status bit will be asserted.
Bit 3 - EXT6_APD - Enables the DP6 / DN7 and DN6 / DP7 pins to support two anti-parallel diode
connections versus a single diode connection.
„
‘0’ (default - EMC1438-2) - The DP6 / DN7 and DN6 / DP7 pins do not support two anti-parallel
diode connections. The pins will only monitor a single external diode (External Diode 6).
„
‘1’ (default - EMC1438-1) - The DP6 / DN7 and DN6 / DP7 pins support two anti-parallel diode
connections (External Diode 6 and External Diode 7).
Bit 2 - EXT4_APD - Enables the DP4 / DN5 and DN4 / DP5 pins to support two anti-parallel diode
connections versus a single diode connection.
„
‘0’ (default - EMC1438-2) - The DP4 / DN5 and DN4 / DP5 pins do not support two anti-parallel
diode connections. The pins will only monitor a single external diode (External Diode 4).
„
‘1’ (default - EMC1438-1) - The DP4 / DN5 and DN4 / DP5 pins support two anti-parallel diode
connections (External Diode 4 and External Diode 5).
Bit 1 - EXT2_APD - Enables the DP2 / DN3 and DN2 / DP3 pins to support two anti-parallel diode
connections versus a single diode connection.
6.22
„
‘0’ (default - EMC1438-2) - The DP2 / DN3 and DN2 / DP3 pins do not support two anti-parallel
diode connections. The pins will only monitor a single external diode (External Diode 2).
„
‘1’ (default - EMC1438-1) - The DP2 / DN3 and DN2 / DP3 pins support two anti-parallel diode
connections (External Diode 2 and External Diode 3).
Filter Control Register
Table 6.27 Filter Control Register
ADDR
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
40h
R/W
Filter Control
AVG7_
EN
AVG6_
EN
AVG5_
EN
AVG4_
EN
AVG3_
EN
AVG2_
EN
AVG1_
EN
-
00h
The Filter Configuration Register controls the digital filter on the external diode channels (see Section
5.6.3, "Digital Averaging").
Bits 7 - 0 - AVGx_EN - Control the digital averaging that is applied to the External Diode X temperature
measurements.
„
‘0’ (default) - Digital Averaging is disabled.
„
‘1’ - Digital averaging is enabled as a 4x running average for the External Diode X channel.
Bit 5 - This bit is part of the test mux encoding but is ignored.
SMSC EMC1438
43
DATASHEET
Revision 1.0 (04-29-10)
1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
6.23
Product ID Register
Table 6.28 Product ID Register
ADDR
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
FDh
R
Product ID
0
1
0
1
1
0
0
1
59h
The Product ID Register holds a unique value that identifies the device.
6.24
Manufacturer ID Register (FEh)
Table 6.29 Manufacturer ID Register
ADDR.
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
FEh
R
Manufacturer
ID
0
1
0
1
1
1
0
1
5Dh
The Manufacturer ID Register holds an 8-bit word that identifies SMSC.
6.25
Revision Register (FFh)
Table 6.30 Revision Register
ADDR.
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
FFh
R
Revision
0
0
0
0
0
0
0
0
00h
The Revision register contains an 8-bit word that identifies the die revision.
Revision 1.0 (04-29-10)
44
DATASHEET
SMSC EMC1438
1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
Chapter 7 Package Information
7.1
EMC1438 Package Drawing
Figure 7.1 16-Pin QFN 4mm x 4mm Package Drawing
SMSC EMC1438
45
DATASHEET
Revision 1.0 (04-29-10)
1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
Figure 7.2 16-Pin QFN 4mm x 4mm PCB Footprint
Figure 7.3 16-Pin QFN 4mm x 4mm Package Dimensions
Revision 1.0 (04-29-10)
46
DATASHEET
SMSC EMC1438
1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
7.2
7.2.1
Package Markings
EMC1438 (16-Pin 4mm x 4mm QFN)
TOP
0.41
LINE: 1 – SMSC Logo without circled (R) symbol
LINE: 2 – Device ID, Version
LINE: 3 – Last 7 digits of Lot Number
LINE: 4 – Revision and Country Code (RCC)
3x 0.56
E 1 4 3 8 - V
1 2 3 4 5 6 a
R C C
e3
PB-FREE/GREEN SYMBOL
(Matte Sn)
PIN 1
LINES 1 to 3: CENTER HORIZONTAL ALIGNMENT
LINE 4: LEFT HORIZONTAL ALIGNMENT
BOTTOM
BOTTOM MARKING NOT ALLOWED
Figure 7.4 EMC1438 Package Marking
SMSC EMC1438
47
DATASHEET
Revision 1.0 (04-29-10)
1°C Multiple Temperature Sensor with Hardware Controlled Standby & Hottest of Multiple Zones
Datasheet
Chapter 8 Datasheet Revision History
Table 8.1 Customer Revision History
REVISION LEVEL AND
DATE
Rev. 1.0 Rev. 1.0 (04-29-10)
Revision 1.0 (04-29-10)
SECTION/FIGURE/ENTRY
CORRECTION
Datasheet release
48
DATASHEET
SMSC EMC1438
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