SMSC EMC2101-ACZT-TR Smbus fan control with 1â°c accurate temperature monitoring Datasheet

EMC2101
SMBus Fan Control
with 1°C Accurate
Temperature Monitoring
PRODUCT FEATURES
Datasheet
General Description
Features
The EMC2101 is an SMBus 2.0 compliant, integrated
fan control solution complete with two temperature
monitors, one external and one internal. Each
temperature channel has programmable high limits that
can assert an interrupt.
„
„
„
„
The fan drive is selectable as a Pulse Width Modulator
(PWM) or Linear (DAC) output. The fan control output,
whether the PWM or DAC drive circuit, uses an eight
position look-up table to allow the user to program the
fan speed profile based on temperature. The DAC output ranges from 0V to VDD with up to 6 bit resolution
while the PWM output has a range of 0% to 100% with
up to 64 steps.
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„
„
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The EMC2101 has an option to automatically upload the
contents of an attached SMBus compatible EEPROM for
auto-programming upon power up.
„
Advanced thermal sensing enables reduced validation
and characterization time as well as accurately operating with smaller-geometry processors. Resistance Error
Correction (REC) automatically corrects the offset errors
of board trace and device resistance, up to 100Ω. Automatic Beta Compensation allows the user the flexibility
to design applications that include processor substrate
transistors.
„
Automatic Beta Compensation
Resistance Error Correction
Self-programming with available SMBus compatible
EEPROM
Selectable PWM or DAC fan driver output
Temperature Monitors
— External channel ±1°C accuracy
— Internal channel ±2°C accuracy
3.3 Volt Operation (5 Volt Tolerant Input Buffers)
SMBus 2.0 Compliant Interface, supports TIMEOUT
8-Pin MSOP Lead-free RoHS Compliant Packages
8-Pin SOIC Lead-free RoHS Compliant Package
Applications
„
„
Graphics Processors
Embedded Application Fan Drive
PWM Controller + Temp Sensor
Block Diagram
VDD
EMC2101
Address Pointer Register
Switching
Current
Analog
Mux
ΔΣ ADC
DN
External
Temperature
Register
Internal
Temperature
Register
Internal
Temp Diode
PWM Driver
FAN
DAC Driver
Internal High Limit Register
External High Limit Register
External TCRIT Limit Register
Fan Control
Look-Up Table
SMCLK
Configuration Register
SMDATA
Interupt Masking
Fan Control
Logic
SMBus Interface
DP
Limit Comparator
Conversion Rate Register
ALERT / TACH
Status Registers
GND
SMSC EMC2101
DATASHEET
Revision 2.54 (06-16-09)
SMBus Fan Control with 1°C Accurate Temperature Monitoring
Datasheet
ORDER NUMBERS:
EMC2101-ACZL-TR FOR 8-PIN, MSOP LEAD-FREE ROHS COMPLIANT PACKAGE
EMC2101-R-ACZL-TR FOR 8-PIN, MSOP LEAD-FREE ROHS COMPLIANT PACKAGE
EMC2101-ACZT-TR FOR 8-PIN, SOIC LEAD-FREE ROHS COMPLIANT PACKAGE
REEL SIZE IS 4,000 PIECES
80 ARKAY DRIVE, HAUPPAUGE, NY 11788 (631) 435-6000, FAX (631) 273-3123
Copyright © 2009 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 2.54 (06-16-09)
2
DATASHEET
SMSC EMC2101
SMBus Fan Control with 1°C Accurate Temperature Monitoring
Datasheet
Table of Contents
Chapter 1 Device Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Chapter 2 Pin Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.1
2.2
Pin Diagram for EMC2101 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Pin Description for EMC2101 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Chapter 3 Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.1
3.2
3.3
3.4
Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SMBus Client Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
EEPROM Loader Electrical Specifications (EMC2101-R only) . . . . . . . . . . . . . . . . . . . . . . . . . . .
10
10
12
13
Chapter 4 System Management Bus Interface Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
4.1
4.2
4.3
4.4
4.5
4.6
4.7
4.8
4.9
System Management Bus Interface Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Write Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Read Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Send Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Receive Byte. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Alert Response Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SMBus Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SMBus Time-out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Programming from EEPROM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15
15
16
16
16
16
17
17
17
Chapter 5 General Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
5.1
5.2
5.3
5.4
5.5
5.6
Modes of Operation (EMC2101-R Only). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Up (EMC2101-R Only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ALERT / TACH Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.4.1
ALERT / TACH as a Temperature Comparator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.4.2
ALERT / TACH as an Interrupt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.4.3
Mask Bit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Temperature Monitors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.5.1
Temperature Measurement Results and Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.5.2
Temperature Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.5.3
Beta Compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.5.4
Resistance Error Correction (REC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.5.5
Programmable Ideality Factor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.5.6
Diode Faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fan Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.6.1
DAC Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.6.2
PWM Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.6.3
TACH Monitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.6.4
Fan Control Look-Up Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
20
20
20
21
21
22
22
22
23
25
26
26
26
26
27
27
27
27
27
Chapter 6 Register Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
6.1
6.2
6.3
6.4
6.5
6.6
Data Read Interlock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Temperature Data Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Status Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Configuration Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Conversion Rate Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SMSC EMC2101
3
DATASHEET
32
32
33
33
34
35
Revision 2.54 (06-16-09)
SMBus Fan Control with 1°C Accurate Temperature Monitoring
Datasheet
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
6.26
Temperature Limit Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
External Temperature Force Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
One Shot Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Scratchpad Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Alert Mask Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
External Ideality Factor Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Beta Compensation Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TACH Reading Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TACH Limit Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fan Configuration Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fan Spin Up Configuration Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fan Setting Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
PWM Frequency Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
PWM Frequency Divide Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fan Control Look-Up Table Hysteresis Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fan Control Look-Up Table Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Averaging Filter Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Product ID Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Manufacturer ID Register (FEh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Revision Register (FFh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
36
36
37
37
37
38
39
40
40
41
42
43
44
44
45
46
47
48
48
48
Chapter 7 Package Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Appendix A Advanced PWM Options. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Appendix B TACH Reference Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Revision 2.54 (06-16-09)
4
DATASHEET
SMSC EMC2101
SMBus Fan Control with 1°C Accurate Temperature Monitoring
Datasheet
List of Figures
Figure 2.1
Figure 4.1
Figure 5.1
Figure 5.2
Figure 5.3
Figure 5.4
Figure 5.5
Figure 5.6
Figure 5.7
Figure 5.8
Figure 9.1
Figure 9.2
EMC2101 Pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
SMBus Timing Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
System Diagram for EMC2101 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
System Diagram for EMC2101-R. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Block Diagram of Temperature Monitoring Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
External Diode configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Temperature Filter Step Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Temperature Filter Impulse Response. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Fan Control Look-Up Table Example. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Example Fault Queue Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
8-PIN MSOP / TSSOP Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
8-PIN SOIC Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
SMSC EMC2101
5
DATASHEET
Revision 2.54 (06-16-09)
SMBus Fan Control with 1°C Accurate Temperature Monitoring
Datasheet
List of Tables
Table 1.1 Device Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Table 2.1 Pin Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Table 2.2 Pin Types. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Table 3.1 Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Table 3.2 Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Table 3.3 SMBus Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Table 3.4 EEPROM Loader Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Table 4.1 Protocol Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Table 4.2 Write Byte Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Table 4.3 Read Byte Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Table 4.4 Send Byte Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Table 4.5 Receive Byte Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Table 4.6 Alert Response Address Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Table 4.7 Block Read Byte Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Table 5.1 ALERT/ TACH Pull-up Resistors - SMBus / FAN MODE for EMC2101-R . . . . . . . . . . . . . . . 21
Table 5.2 EMC2101 External Temperature Data Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Table 5.3 EMC2101 Internal Temperature Data Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Table 6.1 Register Set in Hexadecimal Order . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Table 6.2 Temperature Data Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Table 6.3 Status Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Table 6.4 Configuration Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Table 6.5 Conversion Rate Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Table 6.6 Conversion Rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Table 6.7 Temperature Data Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Table 6.8 External Diode Force Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Table 6.9 One Shot Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Table 6.10 Scratchpad Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Table 6.11 Alert Mask Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Table 6.12 External Ideality Factor Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Table 6.13 Ideality Factor Look-Up Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Table 6.14 Beta Compensation Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Table 6.15 CPU Beta Values. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Table 6.16 TACH Reading Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Table 6.17 TACH Reading Low Byte Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Table 6.18 Fan Configuration Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Table 6.19 TACH Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Table 6.20 Fan Spin Up Configuration Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Table 6.21 Spin-Up Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Table 6.22 Spin-Up Time. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Table 6.23 Fan Setting Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Table 6.24 PWM Frequency Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Table 6.25 PWM Frequency Divide Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Table 6.26 Examples of Fan PWM Frequency with Maximum Resolution . . . . . . . . . . . . . . . . . . . . . . . . 45
Table 6.27 Look Up Table Hysteresis Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Table 6.28 Fan Control Look Up Table Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Table 6.29 Averaging Filter Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Table 6.30 Averaging Settings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Table 6.31 Product ID Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Table 6.32 Manufacturer ID Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Table 6.33 Revision Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Customer Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Revision 2.54 (06-16-09)
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DATASHEET
SMSC EMC2101
SMBus Fan Control with 1°C Accurate Temperature Monitoring
Datasheet
Chapter 1 Device Selection
The EMC2101 is available with the following options and configurations as shown in Table 1.1.
Table 1.1 Device Selection
PART NUMBER
FAN OPERATION
COMMUNICATIONS
PACKAGE
PRODUCT ID
EMC2101
PWM Drive, 0% drive
SMBus
8 pin SOIC and
8 pin MSOP
16h
EMC2101-R
Selected via pull-up
Selected via pull-up
8 pin MSOP
28h
SMSC EMC2101
7
DATASHEET
Revision 2.54 (06-16-09)
SMBus Fan Control with 1°C Accurate Temperature Monitoring
Datasheet
Chapter 2 Pin Layout
2.1
Pin Diagram for EMC2101
8
SMCLK
7
SMDATA
3
6
ALERT / TACH
4
5
GND
VDD
1
DP
2
DN
FAN
EMC2101
Figure 2.1 EMC2101 Pinout
2.2
Pin Description for EMC2101
Table 2.1 Pin Description
PIN
NAME
1
VDD
2
FUNCTION
TYPE
3.3V Power supply
Power
DP
External diode positive (anode)
connection
AI
3
DN
External diode negative (cathode)
connection
AI
4
FAN
PWM Output
(default - software programmed)
OD (5V)
DAC Output
software programmed
AO
Ground
Power
ALERT - Open drain I/O operates as
active low interrupt or TACH input requires pull-up resistor, which defines
auto-configuration mode (see
Table 5.1)
OD (5V)
TACH - TACH input
DI (5V)
5
GND
6
ALERT / TACH
7
SMDATA
SMBus Data input/output
DIOD Output (5V)
8
SMCLK
SMBus Clock input
DIOD Output (5V)
The pin types are described below. All pins labelled with (5V) are 5V tolerant.
Revision 2.54 (06-16-09)
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DATASHEET
SMSC EMC2101
SMBus Fan Control with 1°C Accurate Temperature Monitoring
Datasheet
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 Types
SMSC EMC2101
PIN TYPE
DESCRIPTION
Power
This pin is used to supply power or ground to the device.
DI
Digital Input - this pin is used as a digital input. This pin is
5V tolerant.
AI
Analog Input - this pin is used as an input for analog
signals.
AO
Analog Output - this pin is used as an output for analog
signals.
DIOD
Digital Input / Open Drain Output - this pin is used as a
digital I/O. When it is used as an output, it is open drain
and requires a pull-up resistor. This pin is 5V tolerant.
OD
Open Drain Digital Output - this pin is used as a digital
output. It is open drain and requires a pull-up resistor. This
pin is 5V tolerant.
9
DATASHEET
Revision 2.54 (06-16-09)
SMBus Fan Control with 1°C Accurate Temperature Monitoring
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 5.0
V
Voltage on 5V tolerant pins (V5VT_pin)
-0.3 to 5.5
V
Voltage on 5V tolerant pins (|V5VT_pin - VDD|) (see Note 3.1)
-0.3 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 any other pin to Ground
Lead Temperature Range
Refer to JEDEC Spec. J-STD020
Package Thermal Characteristics for MSOP-8
Thermal Resistance
140.8
°C/W
135.9
°C/W
2000
V
Package Thermal Characteristics for SOIC-8
Thermal Resistance
ESD Rating, All pins HBM
Note: Stresses 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. When powering this device from
laboratory or system power supplies, it is important that the Absolute Maximum Ratings not be
exceeded or device failure can result. Some power supplies exhibit voltage spikes on their
outputs when the AC power is switched on or off. In addition, voltage transients on the AC
power line may appear on the DC output. If this possibility exists, it is suggested that a clamp
circuit be used.
Note 3.1
3.2
For the 5V tolerant pins that have a pull-up resistor, the pull-up voltage must not exceed
3.6V when the EMC2101 is unpowered.
Electrical Specifications
Table 3.2 Electrical Specifications
VDD = 3.0V to 3.6V, TA = 0oC - 85oC, Typical values are at TA = 27°C unless otherwise noted
CHARACTERISTIC
SYMBOL
MIN
TYP
MAX
UNIT
CONDITIONS
DC Power
Supply Voltage
Revision 2.54 (06-16-09)
VDD
3.0
3.3
3.6
10
DATASHEET
V
SMSC EMC2101
SMBus Fan Control with 1°C Accurate Temperature Monitoring
Datasheet
Table 3.2 Electrical Specifications (continued)
VDD = 3.0V to 3.6V, TA = 0oC - 85oC, Typical values are at TA = 27°C unless otherwise noted
CHARACTERISTIC
SYMBOL
MIN
TYP
MAX
1
UNIT
CONDITIONS
mA
16 conversion / second - PWM or
DAC driver operational
Supply Current
IDD
0.6
Supply Current
IDD
200
uA
1 conversion / 16 seconds - PWM
driver operational
Supply Current
IDD
300
uA
1 conversion / 16 seconds - DAC
Driver, no load
Supply Current
IDD
300
400
uA
Temp monitoring Disabled, DAC
Driver enabled, no load
Standby Current
ISTANDBY
270
μA
PWM disabled, Monitoring
disabled
Internal Temperature Monitor
Temperature Accuracy
±1
Temperature
Resolution
±1
°C
3
ms
Conversion Time
Internal Channel
tCONV
±2
°C
8 bit resolution
External Temperature Monitor
Temperature Accuracy
Temperature
Resolution
±0.5
±1
°C
60°C < TDIODE < 100°C,
10°C < TA < 70°C
±1
±3
°C
0°C < TDIODE < 125°C
0.125
°C
11 bit resolution
21
ms
Conversion Time
External Channel
tCONV
Diode Decoupling
Capacitor
CFILTER
2.2
nF
Connected across External Diode
(2N3904)
Diode Decoupling
Capacitor
CFILTER
470
pF
Connected across Substrate
Transistor (CPU diode)
Resistance Error
Correction
RSERIES
Ω
Series resistance in DP and DN
lines
%
TACH valid
100
TACH Measurement
TACH Accuracy
10
Fan Counter Clock
Frequency
90
kHz
Pulse Width Modulator Fan Driver
PWM Resolution
PWM Frequency
SMSC EMC2101
64
fPWM
steps
22
5k
11
DATASHEET
Hz
For 64 steps, higher frequencies
are possible with reduced
resolution (see Appendix A
"Advanced PWM Options").
Revision 2.54 (06-16-09)
SMBus Fan Control with 1°C Accurate Temperature Monitoring
Datasheet
Table 3.2 Electrical Specifications (continued)
VDD = 3.0V to 3.6V, TA = 0oC - 85oC, Typical values are at TA = 27°C unless otherwise noted
CHARACTERISTIC
PWM Duty cycle
SYMBOL
MIN
DPWM
TYP
MAX
0
UNIT
100
CONDITIONS
%
DAC Fan Driver
Output Voltage Drive
VDAC
Total Unadjusted Error
TUE
0.2
DAC Resolution
Settling Time to within
1%
tSETTLE
VDD - 0.2
V
Current Load = ±1mA
5
%
Measured at 3/4 full scale
6
bits
40
us
Capacitive Load = 100pF
Digital I/O pins (PWM, SMDATA, SMCLK, ALERT / TACH)
Output High Voltage
VOH
Output Low Voltage
VOL
Output Leakage
Current
ILEAK
3.3
VDD 0.3
V
8mA Current Source
0.3
V
8mA Current Sink
10
uA
Device powered or unpowered
TA < 85°C
pull-up voltage < 3.6V
SMBus Client Electrical Specifications
Table 3.3 SMBus Electrical Specifications
VDD = 3.0V to 3.6V, TA = 0oC - 85oC, Typical values are at TA = 27°C unless otherwise noted
CHARACTERISTIC
SYMBOL
MIN
TYP
MAX
UNITS
CONDITIONS
SMBus Interface
Input High Voltage
VIH
Input Low Voltage
VIL
Input High/Low Current
IIH / IIL
2.1
-1
Hysteresis
Input Capacitance
V
CIN
Output Low Sink Current
0.8
V
1
uA
500
mV
5
pF
8
mA
VOL = 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
Revision 2.54 (06-16-09)
10
400
kHz
50
ns
12
DATASHEET
SMSC EMC2101
SMBus Fan Control with 1°C Accurate Temperature Monitoring
Datasheet
Table 3.3 SMBus Electrical Specifications (continued)
VDD = 3.0V to 3.6V, TA = 0oC - 85oC, Typical values are at TA = 27°C unless otherwise noted
CHARACTERISTIC
SYMBOL
MIN
Setup Time: Stop
tSU:STO
0.6
us
Data Hold Time
tHD:DAT
0.3
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 (Note 3.2)
Capacitive Load
CLOAD
400
pF
per bus line
Note 3.2
3.4
TYP
MAX
UNITS
CONDITIONS
300ns rise time max is required for 400kHz bus operation. For lower clock frequencies the
maximum rise time is (0.1 / fSMB)+ 50ns.
EEPROM Loader Electrical Specifications (EMC2101-R only)
Table 3.4 EEPROM Loader Electrical Specifications
VDD = 3.0V to 3.6V, TA = 0oC - 85oC, Typical values are at TA = 27°C unless otherwise noted
CHARACTERISTIC
SYMBOL
MIN
TYP
MAX
UNITS
CONDITIONS
Interface
Input High Voltage
VIH
Input Low Voltage
VIL
Input High/Low Current
IIH / IIL
2.1
-1
Hysteresis
Input Capacitance
V
CIN
Output Low Sink Current
0.8
V
1
uA
500
mV
5
pF
8
mA
VOL = 0.4V
Delay after power-up until EEPROM
loading begins. (See Section 4.9.)
Timing
Loading Delay
tDLY
10
ms
Loading Time
tLOAD
50
ms
Clock Frequency
fSMB
50
kHz
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
SMSC EMC2101
50
13
DATASHEET
ns
Revision 2.54 (06-16-09)
SMBus Fan Control with 1°C Accurate Temperature Monitoring
Datasheet
Table 3.4 EEPROM Loader Electrical Specifications (continued)
VDD = 3.0V to 3.6V, TA = 0oC - 85oC, Typical values are at TA = 27°C unless otherwise noted
CHARACTERISTIC
SYMBOL
MIN
Setup Time: Stop
tSU:STO
0.6
us
Data Hold Time
tHD:DAT
0.3
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
Capacitive Load
CLOAD
400
pF
per bus line
Revision 2.54 (06-16-09)
TYP
MAX
14
DATASHEET
UNITS
CONDITIONS
SMSC EMC2101
SMBus Fan Control with 1°C Accurate Temperature Monitoring
Datasheet
Chapter 4 System Management Bus Interface Protocol
4.1
System Management Bus Interface Protocol
The EMC2101 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 EMC2101 will not stretch the clock signal.
The EMC2101 powers up as an SMBus client (after loading from EEPROM as applicable).
TLOW
THIGH
THD:STA
TSU:STO
TRISE
SMCLK
THD:STA
TFALL
THD:DAT
TSU:STA
TSU:DAT
SMDTA
TBUF
S
P
S
S - Start Condition
P - Stop Condition P
Figure 4.1 SMBus Timing Diagram
The EMC2101 is SMBus 2.0 compatible and supports Send Byte, Read Byte, Receive Byte and the
Alert Response Address as valid protocols as shown below.
All of the below protocols use the convention in Table 4.1.
Table 4.1 Protocol Format
DATA SENT TO
THE HOST
DATA SENT
TO DEVICE
# of bits sent
4.2
# of bits sent
Write Byte
The Write Byte is used to write one byte of data to the registers as shown below Table 4.2.
Table 4.2 Write Byte Protocol
START
SLAVE
ADDRESS
WR
ACK
REGISTER
ADDRESS
ACK
REGISTER
DATA
ACK
STOP
1
7
1
1
8
1
8
1
1
SMSC EMC2101
15
DATASHEET
Revision 2.54 (06-16-09)
SMBus Fan Control with 1°C Accurate Temperature Monitoring
Datasheet
4.3
Read Byte
The Read Byte protocol is used to read one byte of data from the registers as shown in Table 4.3.
Table 4.3 Read Byte Protocol
START
SLAVE
ADDRESS
WR
ACK
Register
Address
ACK
START
Slave
Address
RD
ACK
Register
Data
NACK
STOP
1
7
1
1
8
1
1
7
1
1
8
1
1
4.4
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 4.4.
Table 4.4 Send Byte Protocol
START
SLAVE
ADDRESS
WR
ACK
REGISTER
ADDRESS
ACK
STOP
1
7
1
1
8
1
1
4.5
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 4.5.
Table 4.5 Receive Byte Protocol
START
SLAVE
ADDRESS
RD
ACK
REGISTER DATA
NACK
STOP
1
7
1
1
8
1
1
4.6
Alert Response Address
The ALERT / TACH output can be used as a processor interrupt or as an SMBus Alert when configured
to operate as an interrupt.
When it detects that the ALERT / TACH pin is asserted, the host will send the Alert Response Address
(ARA) to the general address of 000_1100b. All devices with active interrupts will respond with their
client address as shown in Table 4.6.
Table 4.6 Alert Response Address Protocol
START
ALERT
RESPONSE
ADDRESS
RD
ACK
DEVICE
ADDRESS
NACK
STOP
1
7
1
1
8
1
1
Revision 2.54 (06-16-09)
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SMSC EMC2101
SMBus Fan Control with 1°C Accurate Temperature Monitoring
Datasheet
The EMC2101 will respond to the ARA in the following way when the ALERT / TACH pin is configured
as an Interrupt:
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 / TACH pin only if there are no bits set in the Status Register.
If there are error condition bits set in the Status Register, it must be read before the MASK bit will
be set.
When the ALERT / TACH pin is configured to operate in Comparator Mode, or as a TACH input, (see
Section 5.4.1), it will not respond to the ARA command. Additionally, the EMC2101 will not respond to
the ARA command if the ALERT / TACH pin is not asserted.
4.7
SMBus Address
The EMC2101 is addressed on the SMBus as 100_1100b.
Attempting to communicate with the EMC2101 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.
4.8
SMBus Time-out
The EMC2101 includes an SMBus time-out feature. Following a 25ms period of inactivity on the
SMBus, the device will time-out and reset the SMBus interface.
4.9
Programming from EEPROM
The EMC2101-R acts as a simple SMBus Master to read data from a connected EEPROM using the
following procedure:
1. After power-up the EMC2101-R waits for 10ms with the SMDATA and SMCLK pins tri-stated.
2. Once the wait period has elapsed, the EMC2101-R sends a START signal followed by the 7 bit
client address 101_0000b followed by a ‘1b’ and waits for an ACK signal from the EEPROM.
3. When the EEPROM sends the ACK signal, the EMC2101-R will send a second start signal and
continue sending the Block Read Command (see Table 4.7) to the same slave address. It reads
256 data bytes from the EEPROM sending an ACK between each data byte. When 256 data bytes
have been received, it sends a NACK signal followed by a STOP bit.
4. Resets the device as an SMBus Client.
If the EMC2101-R does not receive an acknowledge bit from the EEPROM then the following will
occur:
1. The ALERT / TACH pin will be asserted and will remain asserted until a Host device initiates
communication with the EMC2101 and reads the Status Register at offset 0x02. The ALERT /
TACH pin will be de-asserted after a single Status Register read, i.e. it is not sticky.
2. The EMC2101-R will reset its SMBus protocol as a slave interface and start operating from the
default conditions.
SMSC EMC2101
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Table 4.7 Block Read Byte Protocol
START
SLAVE
ADDRESS
WR
ACK
Register
Address
ACK
START
SLAVE
ADDRESS
RD
ACK
Register
Data
...
1
7
1
1
8
1
1
7
1
1
8
...
ACK
Register
Data (00h)
ACK
Register
Data (01h)
ACK
Register
Data (02h)
...
ACK
Register
Data (FFh)
NACK
STOP
1
8
1
8
1
8
...
1
8
1
1
Note: The shaded columns represent data sent from the EMC2101 to the EEPROM device.
APPLICATION NOTE: It is recommended that the EEPROM that is used be an AT24C02B or equivalent device.
The EEPROM slave address must be 101_0000b. The device must support a block-read
command, 8-bit addressing, and 8-bit data formatting using a 2-wire bus. The device must
support 3.3V digital switching logic and may not pull the SMCLK and SMDATA pins above
5V. Data must be transmitted MSB first.
APPLICATION NOTE: No other SMBus Master should exist on the SMDATA and SMCLK lines. The presence of
another SMBus Master will cause errors in reading from the EEPROM.
The EEPROM should be loaded to mirror the register set of the EMC2101 with the desired
configuration set. All undefined registers in the EMC2101 register set should be loaded with 00h in the
EEPROM. Likewise, all registers that are read-only in the EMC2101 register set should be loaded with
00h in the EEPROM.
Because of the interaction between the Fan Control Look-up Table and the Fan Configuration Register,
the EEPROM Loader stores the contents of the Fan Configuration Register and updates this register
at the end of the EEPROM loading cycle. (See Section 6.16 and Section 6.22).
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Chapter 5 General Description
The EMC2101 is an environmental monitoring device with a selectable PWM or DAC fan driver output,
one external temperature monitoring channel and one internal temperature monitor. It contains
advanced circuitry to remove errors induced by series resistance and CPU thermal diode process
differences to provide accurate temperature measurements and accurate fan control.
Thermal management is performed automatically. The EMC2101 reads the temperature from both the
external and internal temperature diodes and uses the external temperature data to control the fan
speed.
The FAN output can be configured as a PWM (default) or DAC output. The PWM fan driver uses an
eight entry look up table to create a programmable temperature response. The DAC output provides
a linear drive for the system fan circuit using this same look up table.
Each temperature measurement channel is continuously compared against programmed high limits.
The external diode channel is compared against a programmed low limit. ALERT / TACH interrupt pin
is asserted if the measured value exceeds the high limit or drops below the low limit. In addition, the
external diode contains a programmable critical temperature, TCRIT. If the measured temperature
exceeds this TCRIT an interrupt is asserted on the ALERT / TACH pin and the fan is set to full on.
Finally, the EMC2101-R (only) has two configuration modes and two default fan settings based on the
value of the pull-up-resistor on the ALERT / TACH pin. In the Manual Configuration Mode, the device
acts as an SMBus client and waits to be configured by the system SMBus host. In the Automatic
Configuration mode, the device automatically queries the SMBus for an EEPROM device and uploads
configuration information from the EEPROM into its internal registers.
Figure 5.1 shows a system level block diagram of the EMC2101. Figure 5.2 shows a system level block
diagram of the EMC2101-R.
HOST
EMC2101
Thermal
diode
DP
SMCLK
DN
Internal
Diode
SMDATA
ALERT
FAN
SMBus
Interface
Fan Drive
Circuitry
Figure 5.1 System Diagram for EMC2101
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EMC2101-R
SMBus
Client
EEPROM
Loader
GPU
EEPROM
or Host
SMCLK
SMDATA
DP
Thermal
diode
DN
Internal
Diode
ALERT
FAN
Fan Drive
Circuitry
Figure 5.2 System Diagram for EMC2101-R
5.1
Modes of Operation (EMC2101-R Only)
The EMC2101-R has two modes of operation based on the pull-up resistor on the ALERT pin (see
Table 5.1). The modes of operation are:
1. Host Configuration Mode - An SMBus Host configures the EMC2101-R upon startup to allow for
polling for temperature or fan information or the user can use the ALERT pin interrupt to determine
which action is required.
2. Automatic Configuration Mode - The EMC2101-R queries an SMBus compatible EEPROM located
at a known address (see Section 4.9) and automatically loads its registers with the contents of the
EEPROM. This mode does not require host intervention but a host can poll the device for
temperature and fan information.
5.2
Power Up (EMC2101-R Only)
The EMC2101-R (only) will power up with the fan driver set to either 100% duty cycle or 0% duty cycle,
depending on the value of the pull-up resistor on the ALERT / TACH pin. (See Table 5.1.) It will remain
in this state until either the Fan Setting Register is written or until the following activities have occurred:
1. The Fan Control Look-Up Table is loaded and the PROG bit is set to ‘0’
2. The temperature monitoring block performs its first comparison against the Look-Up Table.
If the Fan Control Look-Up Table is used, the EMC2101-R Fan Driver will be immediately set to the
appropriate setting in the table based on the measured temperature.
5.3
Power Modes
The EMC2101 supports multiple power modes that are user configurable. The temperature monitoring
and fan control functions of the device are independent. The power modes are:
1. Normal - the temperature monitoring and fan driver circuits are both active. The device updates all
temperature channels at the user programmed conversion rate (see Table 6.6). Every time the
temperature is updated, the limits are checked and the fan driver is updated based on the values
in the Fan Control Look-Up Table (if the Fan Control Look-Up Table is enabled).
2. Standby - the temperature monitoring and fan driver circuits are both disabled. The device will not
update temperature data automatically and the fan output will be set to default drive. A one-shot
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command can be issued that will refresh the temperature data. The limits are only checked when
the temperature data is updated.
3. Mixed - the temperature monitoring block is disabled, but the fan driver block is active. The device
will not update temperature data automatically and the fan driver output will not be updated
automatically based on temperature. A one-shot command can be issued that will refresh the
temperature data and update the fan driver based on the values in the Fan Control Look-Up Table
(if the Fan Control Look-Up Table is enabled).
5.4
ALERT / TACH Output
The ALERT / TACH pin (Pin 6) is an open drain output and requires a pull-up resistor to VDD when
configured as an ALERT output.
APPLICATION NOTE: When configured as a TACH input, the ALERT / TACH pin will not function as an ALERT
output. Error conditions will not trigger an interrupt (though will be updated in the Status
Registers as normal) and the MASK bits will do nothing. Likewise, the device will not respond
to the ARA command.
For the EMC2101-R, the value of this pull-up resistor determines the initial FAN output mode of
operation as well as whether the device auto loads from an EEPROM or via an SMBus host per
Table 5.1.
After power-up, the EMC2101-R requires 10ms to initialize and determine the operating mode.
When configured as an interrupt, the ALERT / TACH pin is maskable for each alert condition. If the
ALERT / TACH pin is masked, then it will not respond to the corresponding condition (though the Alert
Status Register will update normally). This pin has multiple functions described below and is controlled
by ALERT_COMP bit (bit 0) in the Averaging Filter Register (BFh) (see Section 6.23).
Table 5.1 ALERT/ TACH Pull-up Resistors - SMBus / FAN MODE for EMC2101-R
ALERT / TACH
PULL-UP RESISTOR
SMBUS MODE
FAN MODE
POLARITY BIT
SETTING (SEE
Section 6.16)
5.6k Ohm ±5%
Host Load via SMBus
FAN output initialize to 100%
Duty Cycle
1
10k Ohm ±5%
Host Load via SMBus
FAN output initialize to 0% Duty
Cycle
0
18k Ohm ±5%
Auto Load via
EEPROM
FAN output initialize to 100%
Duty Cycle
1
33k Ohm ±5%
Auto Load via
EEPROM
FAN output initialize to 0% Duty
Cycle
0
5.4.1
ALERT / TACH as a Temperature Comparator
When the ALERT / TACH pin is used as a temperature comparator, the ALERT / TACH output is
asserted when an out of limit measurement (> high limit, < low limit, or > TCRIT limit) is detected on
any diode (low limits only apply to the external diode channel) or when the external diode connections
are open. When the condition is no longer true, the ALERT / TACH output will de-assert. Reading from
the Status Register will cause the ALERT / TACH pin to be released however it will not prevent it from
being re-asserted based on the temperature comparisons.
Setting the MASK bit will not affect the ALERT / TACH pin when it is configured as a temperature
comparator, however the individual channel mask bits will block the ALERT / TACH pin from being
asserted.
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5.4.2
ALERT / TACH as an Interrupt
When the ALERT / TACH pin is used as an interrupt signal the pin is asserted whenever an out-oflimit condition is detected. The ALERT / TACH pin will remain asserted until it is cleared even if the
error condition is removed.
5.4.3
Mask Bit
The MASK bit behaves differently depending on which mode the ALERT / TACH pin is configured to
operate in.
If the EMC2101 is configured with the ALERT / TACH pin operating in Interrupt Mode, the MASK bit
will be set in the following cases:
1. Automatically after the Status Register has been read if any bits in the Status Register have been
set (except BUSY and FAULT) (See Table 6.3).
2. Automatically when the EMC2101 responds to an Alert Response Address (ARA) command on an
SMBus and the ALERT / TACH pin is asserted. The ARA command does not clear the Status
Register. If the MASK bit is cleared prior to reading and clearing the Status Register, then the
ALERT / TACH pin will be asserted.
3. Directly via the SMBus.
In Interrupt Mode, the MASK bit will block the ALERT / TACH pin from being asserted in response to
an error condition.
If the EMC2101 is configured with the ALERT / TACH pin operating in Comparator Mode, the MASK
bit can only be set via the SMBus. In this mode, setting the MASK bit willl not affect the ALERT / TACH
pin.
In either mode, setting the individual channel mask bits will block the appropriate channel from
asserting the ALERT / TACH pin.
5.5
Temperature Monitors
In general, thermal diode temperature measurements are based on the change in forward bias voltage
of a diode when operated at two different currents. The change in forward bias voltage is proportional
to absolute temperature (T).
Where:
k = Boltzmann’s constant
ΔVBE = VBE _ HIGH − VBE _ LOW =
⎛I
ln⎜⎜ HIGH
q
⎝ I LOW
ηkT
⎞
⎟⎟
⎠
T = Absolute Temperature in Kelvin
Eq: [1]
q = electron charge
η = Diode Ideality Factor
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.
IHIGH
Resistance
Error
Correction
CPU
substrate
PNP
ILOW
Input
Filter &
Sampler
ΔΣ ADC
Figure 5.3 Block Diagram of Temperature Monitoring Circuit
Figure 5.3 shows a block diagram of the temperature measurement circuit. As shown, the EMC2101
incorporates a delta-sigma analog to digital converter that integrates the temperature diode voltage
from multiple bias currents.
The external temperature diodes can be connected as shown in Figure 5.4.
to
DP
to
DP
to
DP
to
DN
to
DN
to
DN
Local Ground
Typical remote
substrate transistor
i.e. CPU substrate PNP
Typical remote
discrete PNP transistor
i.e. 2N3906
Typical remote
discrete NPN transistor
i.e. 2N3904
Figure 5.4 External Diode configurations
5.5.1
Temperature Measurement Results and Data
The results of the internal and external temperature measurements are stored in the internal and
external temperature registers respectively. These are then compared with the values stored in the
High Limit Registers. The internal temperature measurements are stored in 8-bit format while the
external temperature measurements are stored in 11-bit format.
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The EMC2101 measures temperatures from -64°C to 127°C represented as a binary two’s complement
number. Internal temperatures are in 1°C steps, external temperatures are in 0.125°C steps.
Table 5.2 shows the temperature format for the external diode and Table 5.3 shows the temperature
format for the internal diode.
Table 5.2 EMC2101 External Temperature Data Format
TEMPERATURE (°C)
DIGITAL OUTPUT (BINARY)
<= -64
1 1 0 0
0 0 0 0
0 0 0
-55
1 1 0 0
1 0 0 1
0 0 0
-1
1 1 1 1
1 1 1 1
0 0 0
-0.125
1 1 1 1
1 1 1 1
1 1 1
0
0 0 0 0
0 0 0 0
0 0 0
0.125
0 0 0 0
0 0 0 0
0 0 1
1
0 0 0 0
0 0 0 1
0 0 0
25
0 0 0 1
1 0 0 1
0 0 0
125
0 1 1 1
1 1 0 1
0 0 0
>= 127.875
0 1 1 1
1 1 1 1
1 1 0
Diode Fault (Open condition)
0 1 1 1
1 1 1 1
0 0 0
Diode Fault (Short condition)
0 1 1 1
1 1 1 1
1 1 1
Table 5.3 EMC2101 Internal Temperature Data Format
TEMPERATURE (°C)
Revision 2.54 (06-16-09)
DIGITAL OUTPUT (BINARY)
<= -64
1 1 0 0
0 0 0 0
-55
1 1 0 0
1 0 0 1
-1
1 1 1 1
1 1 1 1
0
0 0 0 0
0 0 0 0
1
0 0 0 0
0 0 0 1
25
0 0 0 1
1 0 0 1
125
0 1 1 1
1 1 0 1
126
0 1 1 1
1 1 1 0
>= 127
0 1 1 1
1 1 1 1
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5.5.2
Temperature Filter
The EMC2101 contains variable filtering options to suppress thermally or electrically noisy signals on
the External Diode lines. This filter can be configured as Level 1, Level 2, or Disabled (see
Section 6.23). The typical filter performance is shown in Figure 5.5 and Figure 5.6.
Filter Step Response
Temperature (C)
90
Disabled
80
70
Level1
Level2
60
50
40
30
20
10
0
0
2
4
6
8
10
12
14
Samples
Figure 5.5 Temperature Filter Step Response
Filter Impulse Response
90
Temperature (C)
80
Disabled
70
60
50
Level1
40
Level2
30
20
10
0
0
2
4
6
8
10
12
14
Samples
Figure 5.6 Temperature Filter Impulse Response
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5.5.3
Beta Compensation
The EMC2101 is software configurable to monitor the temperature of basic diodes (e.g. 2N3904), or
CPU thermal diodes. It automatically detects the type of external diode (CPU diode, diode connected
transistor, or PN diode) and determines the optimal setting to reduce temperature errors introduced by
beta variation.
5.5.4
Resistance Error Correction (REC)
Parasitic resistance in series with the external diode limits the accuracy obtainable from temperature
measurement devices. The voltage developed across this resistance by the switching diode currents
cause the temperature measurement to read higher than the true temperature. Contributors to series
resistance are PCB trace resistance, on die (i.e. on the processor) metal resistance, bulk resistance
in the base and emitter of the temperature transistor. Typically, the error caused by series resistance
is +0.7°C per ohm. Temperature errors caused by up to 100Ω of series resistance are automatically
corrected.
5.5.5
Programmable Ideality Factor
The EMC2101 is designed for an external diode with an ideality factor of 1.008. When an external
diode, processor or discrete, has a different ideality factor, an error is introduced in the temperature
measurement which must be corrected. This is typically done using programmable offset registers but
this correction is only accurate at one temperature since an ideality factor mismatch introduces an error
that is a linear function of temperature. To provide maximum flexibility to the user, the EMC2101
provides a 6-bit register to set the ideality factor for the external diode which eliminates errors across
all temperatures. (See Table 6.13.)
APPLICATION NOTE: This feature is only required in rare circumstances. The majority of errors introduced are
corrected with the Beta Compensation and Resistance Error Correction circuitry.
5.5.6
Diode Faults
The EMC2101 detects the major types of diode faults; an open input DP-DN, a short across DP-DN,
short to GND, and short to VDD. For each temperature measurement made, the device checks for a
diode fault on the external diode.
If an open fault or a short of the DP pin to VDD is detected, then the temperature data is changed to
+127C and the Fault bit in the Status Register will bet set. If the high and / or TCRIT limits are set
below this value, and they are not masked, then the ALERT / TACH pin will be asserted. In addition,
the HIGH and TCRIT status bits will be set accordingly.
If a short between the diode pins or a short to GND is detected, then the temperature data is changed
to +127.875°C. If the high and / or TCRIT limits are set below this value, and they are not masked,
then the ALERT / TACH pin will be asserted. In addition, the HIGH and TCRIT status bits will be set
accordingly. The FAULT bit will not be set.
APPLICATION NOTE: If the Temperature Filter is enabled and a diode fault occurs, the diode fault status bit will be
set and the temperature data is updated immediately. The Filter will stop accumulating data
so long as the diode fault remains in effect.
APPLICATION NOTE: When a Diode Fault is detected, the ALERT / TACH pin behavior is still subject to the Fault
Queue.
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5.6
Fan Control
The EMC2101 includes either a PWM or a linear DAC based fan driver on the shared FAN pin. Both
PWM and DAC use the Fan Control Look-Up Table and/or Fan Setting Register interchangeably as
well as the Spin-Up Routine.
In addition, the EMC2101 can monitor the fan speed using the ALERT / TACH pin.
5.6.1
DAC Driver
The Linear DAC driver included in the EMC2101 has 6-bits of resolution based on the supply voltage
and is used for linear drive fan circuits. Its advantages over PWM drive circuits include reduced circuit
complexity at the expense of reduced effective signal range.
APPLICATION NOTE: When using the DAC Driver, the pull-up resistor on the FAN pin should be removed.
APPLICATION NOTE: The DAC driver output voltage is controlled by either the Fan Setting Register (see
Section 6.18) or the Fan Control Look-Up Table Registers (see Section 6.22). It is also
controlled by the POLARITY bit (see Section 6.16). The PWM Frequency Register (see
Section 6.19) and PWM Divider Register (see Section 6.20) have no effect on the DAC’s
output voltage range, resolution, or response.
5.6.2
PWM Driver
The PWM driver included in the EMC2101 has, at most, 64 steps equalling 1.5% resolution. The
effective resolution, duty cycle, and frequency are all adjustable based on programmed values. It’s
advantages over linear drive circuits include a large signal range (0% to 100% duty cycle) at the
expense of added complexity on the drive circuit.
The PWM output is open drain and requires a pull-up resistor to VDD.
5.6.3
TACH Monitor
The TACH monitor counts the number of clock pulses that occur between five edges of the TACH
signal. The monitor assumes that the tachometer signal is always valid (such as generated from a 4wire fan or a direct drive fan) and that the tachometer signal generates 2 TACH pulses per fan
revolution.
5.6.4
Fan Control Look-Up Table
The EMC2101 uses an 8 entry look-up table to apply a user-programmable fan control profile based
on measured temperature. The user programs the Fan Control Look-Up Table using incrementally
higher temperatures and the desired fan output that should be set when that temperature is reached.
If the measured temperature on the External Diode channel exceeds any of these temperature
thresholds, the fan output will be automatically programmed to the desired setting corresponding to the
exceeded temperature. When the measured temperature drops to a point below any lower threshold
minus the hysteresis value, the fan output will be set to the corresponding lower set point.
Figure 5.7 shows an example of this operation.
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Fan
Setting
Temp
S6
T6
T6 - Hyst
T5
S5
T5 - Hyst
T4
S4
T4 - Hyst
Averaged
Temperature
T3
S3
Fan
Setting
T3 - Hyst
S2
T2
T2 - Hyst
Measurement taken
T1
S1
Time
Figure 5.7 Fan Control Look-Up Table Example
If the Fan Control Look-Up Table is not used, the user may program the fan output directly by writing
to the Fan Setting Register (4Ch - see Section 6.18).
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5.7
Fault Queue
The EMC2101 supports a Fault Queue feature to reduce interrupts caused by spurious temperature
readings. This feature, (see Section 6.5), will not trigger an interrupt until the device has measured
three consecutive out-of-limit HIGH, LOW, or T_CRIT temperature readings. Figure 5.8 shows an
example of this behavior. The Fault Queue only applies to the External Diode channels.
Temp
3 consecutive
errors
2 consecutive
errors
TLIMIT
Status Register ETDS high
n
n+1
n+2
n+3 n+4
n+5
n+6
n+7
n+8
Readings
Figure 5.8 Example Fault Queue Response
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Chapter 6 Register Set
The following registers are accessible through the SMBus Interface. The registers are described in
functional order. Registers with multiple addresses are included for software compatibility. Writing or
reading from either address will point to the same internal register.
Table 6.1 Register Set in Hexadecimal Order
REGISTER
ADDRESS
R/W
REGISTER NAME
FUNCTION
DEFAULT
VALUE
PAGE
00h
R
Internal Temperature
Stores the Internal
Temperature
00h
Page 33
01h
R
External Diode Temperature
High Byte
Stores the External
Temperature High Byte
00h
Page 33
02h
R
Status
Reports internal, external,
and TCRIT alarms
00h
Page 33
03h and 09h
R/W
Configuration
Alert Mask, STANDBY,
TCRIT override, Alert Fault
Queue
00h
Page 34
04h and 0Ah
R/W
Conversion Rate
Sets conversion rate
08h
(16 / sec)
Page 35
05h and 0Bh
R/W
Internal Temp Limit
ALERT / TACH asserted if
measured temp above this
value
46h
(70°C)
Page 36
07h and
0Dh
R/W
External Temp High Limit
High Byte
ALERT / TACH asserted if
measured temp above this
value
46h
(70°C)
Page 36
08h and 0Eh
R/W
External Temp Low Limit
High Byte
ALERT / TACH asserted if
measured temp below this
value
00h
(0°C)
Page 36
0Ch
R/W
External Temperature Force
Force the temperature for
determining the next fan
speed used in the Fan
Control Look-Up Table
00h
Page 36
0Fh
R/W
One Shot
When written, performs a
one-shot conversion.
00h
Page 37
10h
R
External Diode Temperature
Low Byte
Stores the External
Temperature Low Byte
00h
Page 33
11h
R/W
Scratchpad
Scratchpad - This register
is read/write but does
nothing
00h
Page 37
12h
R/W
Scratchpad
Scratchpad - This register
is read/write but does
nothing
00h
Page 37
13h
R/W
External Diode High Limit
Low Byte
Fractional data of High
Limit
00h
Page 36
14h
R/W
External Diode Low Limit
Low Byte
Fractional data of Low
Limit
00h
Page 36
16h
R/W
Alert Mask
Disables alarms
A4h
Page 37
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Table 6.1 Register Set in Hexadecimal Order (continued)
REGISTER
ADDRESS
R/W
REGISTER NAME
FUNCTION
DEFAULT
VALUE
PAGE
17h
R/W
External Diode Ideality
Factor
Sets ideality factor based
on diode type
12h
(1.008)
Page 38
18h
R/W
Beta Compensation Factor
Compensates for
transistors with various
beta factors
08h
Page 39
19h
R/W
TCRIT Temp Limit
Fan will be set to full speed
if external temp above this
value
55h
(85°C)
Page 36
21h
R/W
TCRIT Hysteresis
Amount of hysteresis
applied to TCRIT Temp
(1LSB = 1°C)
0Ah
(10°C)
Page 36
46h
R
TACH Reading Low Byte
Stores the lower 6 bits of
the TACH count. and the
TACH configuration bits
FFh
Page 40
47h
R
TACH Reading High Byte
Stores the upper 8 bits of
the TACH count.
FFh
Page 40
48h
R/W
TACH Limit Low Byte
Stores the lower 6 bits of
the TACH Limit
FFh
Page 40
49h
R/W
TACH Limit High Byte
Stores the upper 8 bits of
the TACH Limit
FFh
Page 40
4Ah
R/W
FAN Configuration
defines polarity of PWM or
DAC
20h
Page 41
4Bh
R/W
Fan Spin-up
Sets Spin Up options
3Fh
Page 42
4Ch
R/W
Fan Setting
Sets PWM or DAC value
00h
Page 43
4Dh
R/W
PWM Frequency
Sets the final PWM
Frequency
17h
Page 44
4Eh
R/W
PWM Frequency Divide
Sets the base PWM
frequency
01h
Page 44
4Fh
R/W
Lookup Table Hysteresis
Amount of hysteresis
applied to Lookup Table
Temp (1LSB = 1°C)
04h
(4°C)
Page 45
50h
R/W (See
Note 6.1)
Lookup Table Temp Setting 1
Look Up Table
Temperature Setting 1
7Fh
Page 46
51h
R/W (See
Note 6.1)
Lookup Table Fan Setting 1
Associated Fan Setting for
Temp Setting 1
3Fh
Page 46
52h
R/W (See
Note 6.1)
Lookup Table Temp Setting 2
Look Up Table
Temperature Setting 2
7Fh
Page 46
53h
R/W (See
Note 6.1)
Lookup Table Fan Setting 2
Associated Fan Setting for
Temp Setting 2
3Fh
Page 46
54h
R/W (See
Note 6.1)
Lookup Table Temp Setting 3
Look Up Table
Temperature Setting 3
7Fh
Page 46
55h
R/W (See
Note 6.1)
Lookup Table Fan Setting 3
Associated Fan Setting for
Temp Setting 3
3Fh
Page 46
56h
R/W (See
Note 6.1)
Lookup Table Temp Setting 4
Look Up Table
Temperature Setting 4
7Fh
Page 46
SMSC EMC2101
31
DATASHEET
Revision 2.54 (06-16-09)
SMBus Fan Control with 1°C Accurate Temperature Monitoring
Datasheet
Table 6.1 Register Set in Hexadecimal Order (continued)
REGISTER
ADDRESS
DEFAULT
VALUE
R/W
REGISTER NAME
FUNCTION
57h
R/W (See
Note 6.1)
Lookup Table Fan Setting 4
Associated Fan Setting for
Temp Setting 4
3Fh
Page 46
58h
R/W (See
Note 6.1)
Lookup Table Temp Setting 5
Look Up Table
Temperature Setting 5
7Fh
Page 46
59h
R/W (See
Note 6.1)
Lookup Table Fan Setting 5
Associated Fan Setting for
Temp Setting 5
3Fh
Page 46
5Ah
R/W (See
Note 6.1)
Lookup Table Temp Setting 6
Look Up Table
Temperature Setting 6
7Fh
Page 46
5Bh
R/W (See
Note 6.1)
Lookup Table Fan Setting 6
Associated Fan Setting for
Temp Setting 6
3Fh
Page 46
5Ch
R/W (See
Note 6.1)
Lookup Table Temp Setting 7
Look Up Table
Temperature Setting 7
7Fh
Page 46
5Dh
R/W (See
Note 6.1)
Lookup Table Fan Setting 7
Associated Fan Setting for
Temp Setting 7
3Fh
Page 46
5Eh
R/W (See
Note 6.1)
Lookup Table Temp Setting 8
Look Up Table
Temperature Setting 8
7Fh
Page 46
5Fh
R/W (See
Note 6.1)
Lookup Table Fan Setting 8
Associated Fan Setting for
Temp Setting 8
3Fh
Page 46
BFh
R/W
Averaging Filter
Selects averaging function
for external diode
00h
Page 47
FDh
R
Product ID
ID
16h or 28h
Page 48
FEh
R
Manufacturer ID
SMSC
5Dh
Page 48
FFh
R
Revision Register
REV
01h
Page 48
Note 6.1
6.1
PAGE
The Look Up Table Registers are made Read Only if the PWM Program bit (bit 5) in PWM
Configuration Register (4Ah) is set.
Data Read Interlock
When the External Diode High Byte Register is read, the External Diode 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
an External Diode High Byte Register will automatically refresh this stored low byte data.
When the TACH Reading Low Byte Register is read, the TACH Reading high byte is copied into an
internal ‘shadow’ register. The user is free to read the high byte at any time and be guaranteed that it
will correspond to the previously read low byte. Regardless if the high byte is read or not, reading from
the TACH Reading Low Byte Register will automatically refresh this stored high byte data.
6.2
Register Descriptions
The registers are described in detail below. A bit entry of a ‘-’ indicates that the bit is not used and will
always read 0.
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SMBus Fan Control with 1°C Accurate Temperature Monitoring
Datasheet
6.3
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
Temperature
Sign
64
32
16
8
4
2
1
00h
01h
R
External Diode
Temperature
High Byte
Sign
64
32
16
8
4
2
1
00h
10h
R
External Diode
Temperature
Low Byte
0.5
0.25
0.125
-
-
-
-
-
00h
As shown in Table 6.2, the internal temperature monitor is stored as an 8-bit value while the external
temperature is stored as an 11-bit value.
Please note that the internal temperature monitor is limited to the operating temperature limits of the
part resulting in a guaranteed range of 0ºC to 85ºC.
6.4
Status Register
Table 6.3 Status Register
ADDR
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
02h
R
Status
BUSY
INT_
HIGH
EEPROM
EXT_
HIGH
EXT_
LOW
FAULT
TCRIT
TACH
00h
The Status Register is a read only register and returns the operational status of the part.
If the ALERT / TACH pin is configured as an ALERT output and any of these bits are set to '1' (except
the BUSY bit and the FAULT bit), then the ALERT / TACH pin is asserted low (if interrupts are not
masked (see Section 6.5).
Reading from the Status Register will cause the MASK bit to be set if any bit (other than BUSY and
FAULT) have been set. Each bit is automatically cleared when the error condition has been removed,
however the internal error condition flags may still be set. The ARA command must be used to clear
the ALERT / TACH pin if there are no bits set in the Status Register. In addition, reading from the
Status Register will clear all bits. If the error condition persists, then the bits will be reset at the end of
the next conversion.
When the device is configured in Comparison Mode (see Section 6.23), reading the Status Register
will not clear any active status bits (except EEPROM and FAULT). These bits are automatically cleared
when the error condition is removed.
Bit 7 - Busy - indicates that the ADC is converting - does not trigger an interrupt.
Bit 6 - INT_HIGH - Internal temperature has met or exceeded the high limit.
Bit 5 - EEPROM - Indicates that the EEPROM could not be found when the device powers up in the
Auto-Program Mode (see Section 5.1). This bit only applies to the EMC2102-R. It will always read ‘0’
for the EMC2101 device.
Bit 4 - EXT_HIGH - External Diode temperature has exceeded the high limit.
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SMBus Fan Control with 1°C Accurate Temperature Monitoring
Datasheet
Bit 3 - EXT_LOW - External Diode temperature has fallen below the low limit.
Bit 2 - FAULT - A diode fault has occurred on the External Diode.
Bit 1 - TCRIT - External Diode Temperature has met or exceeded the TCRIT limit.
Bit 0 - TACH - The TACH count has exceeded the TACH Limit.
6.5
Configuration Register
Table 6.4 Configuration Register
ADDR
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
03h and
09h
R/W
Configuration
MASK
STANDBY
FAN_
STANDBY
DAC
DIS_
TO
ALT_
TCH
TCRIT
OVRD
QUEUE
00h
The configuration register controls the basic functionality of the EMC2101. The bits are described
below:
Bit 7 - MASK - Masks the ALERT / TACH pin functionality when the device is configured as an ALERT
output in Interrupt Mode. This bit is ignored if the ALERT / TACH pin is configured as an ALERT output
in Comparator Mode or if it is configured as a TACH input.
The internal error condition flags are not affected by setting the MASK bit. Therefore, if the MASK bit
is set manually (instead of by reading the Status Register or sending the ARA command), and it is
cleared, the ALERT / TACH pin may be reasserted without any apparent error conditions present. It is
not recommended that the MASK bit be manually set to clear the ALERT / TACH pin.
„
'0' (default) - The ALERT / TACH pin will be asserted if any bit is set in the Status Register. Once
the pin is asserted, it will remain asserted.
„
'1' - the ALERT / TACH pin will be masked and will not generate an interrupt. The Status Register
will still be updated normally.
Bit 6- STANDBY - Determines operational mode of the device.
„
'0' (default) - Operational mode, monitoring temperatures, updating FAN output
„
'1' - Low power standby mode. In this mode, the Temperature monitor is disabled and the Fan
drivers may be disabled depending on the status of the FAN_STANDBY bit.
Bit 5 - FAN_STANDBY - Determines the operation of the FAN driver when the device is put into low
power standby mode.
„
'0' (default) - FAN output will remain active when the STANDBY bit is set.
„
‘1’ - FAN output will be inactive when the STANBDY bit is set. The driver will be set at the default
drive based on the pull-up resistors on the ALERT / TACH pin (see Table 5.1).
Bit 4 - DAC - Determines FAN output mode
„
'0' (default) - PWM output enabled at FAN pin.
„
'1' - DAC output enabled at FAN pin.
Bit 3 - DIS_TO - disables the SMBus Time-out functionality.
„
‘0’ (default) - the SMBus Time-out functionality is enabled and will reset the client block if the clock
is held in a single state for more than 25ms and less than 35ms.
„
‘1’ - the SMBus Time-out functionality is disabled. The client block will only reset if it receives a
STOP bit.
Bit 2 - ALT_TCH - Determines the functionality of the ALERT / TACH pin.
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SMBus Fan Control with 1°C Accurate Temperature Monitoring
Datasheet
„
‘0’ (default) - The ALERT / TACH pin will function as an open drain, active low interrupt.
„
‘1’ - The ALERT / TACH pin will function as a high impedance TACH input. This may require an
external pull-up resistor to set the proper signaling levels.
Bit 1 - TCRITOVRD - Allows the TCRIT limit to be overridden.
„
'0' (default) - TCRIT limit is set to default value and locked.
„
'1' - The TCRIT limit is unlocked for modification. The TCRIT limit can only be changed once. To
adjust TCRIT again, a power cycle is required.
Bit 0 - QUEUE - Sets the number of external diode over-temp measurements required to assert ALERT
/ TACH pin.
6.6
„
'0' (default) - ALERT / TACH pin is asserted (and status bit set) after one external temperature
measurement exceeds the high limit or the TCRIT limit or drops below the low limit.
„
'1' - ALERT / TACH pin is asserted (and status bit set) after three consecutive external temperature
measurements exceed the high limit or the TCRIT limit or drop below the low limit.
Conversion Rate Register
Table 6.5 Conversion Rate Register
ADDR.
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
04h and
0Ah
R/W
Conversion
Rate
-
-
-
-
CONV3
CONV2
CONV1
CONV0
08h
Bits 3- 0 - CONV[3:0] - The Conversion Rate Register controls the conversion rate per Table 6.6.
Table 6.6 Conversion Rates
CONV[3:0]
3
2
1
0
CONVERSIONS PER SECOND
0
0
0
0
1/16
0
0
0
1
1/8
0
0
1
0
1/4
0
0
1
1
1/2
0
1
0
0
1
0
1
0
1
2
0
1
1
0
4
0
1
1
1
8
1
0
0
0
16 (default)
1
0
0
1
32
all others
SMSC EMC2101
32
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Revision 2.54 (06-16-09)
SMBus Fan Control with 1°C Accurate Temperature Monitoring
Datasheet
6.7
Temperature Limit Registers
Table 6.7 Temperature Data Registers
ADDR
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
05h and 0Bh
R/W
Internal Temp
Limit
-
64
32
16
8
4
2
1
46h (70°C)
07h and 0Dh
R/W
External Diode
High Limit MSB
-
64
32
16
8
4
2
1
46h (70°C)
08h and 0Eh
R/W
External Diode
Low Limit MSB
-
64
32
16
8
4
2
1
00h (0°C)
13h
R/W
External Diode
High Limit LSB
0.5
0.25
0.125
-
-
-
-
-
00h
14h
R/W
External Diode
Low Limit LSB
0.5
0.25
0.125
-
-
-
-
-
00h
19h
R/W
TCRIT Temp
Limit
-
64
32
16
8
4
2
1
55h (85°C)
21h
R/W
TCRIT
Hysteresis
-
64
32
16
8
4
2
1
0Ah (10°C)
The EMC2101 has two 8-bit limit registers, two 11-bit limit registers, and one hysteresis register. The
limits are checked after every temperature conversion.
If the measured temperature for the internal diode exceeds the Internal Temperature limit, then the
INT_HIGH bit is set in the Status Register. It will remain set until the internal temperature drops below
the high limit.
If the measured temperature for the External Diode exceeds the 11-bit External Diode High Limit, or
drops below the 11-bit External Diode Low Limit, then the appropriate status bit will be set. The status
bit will remain set until the temperature is no longer violating the respective limits.
If the External Diode exceeds the TCRIT Temp Limit (even if it does not exceed the External Diode
Temperature Limit), the TCRIT bit will be set in the Status Register.
The TCRIT bit will remain set in the Status Register until the External Diode Temperature drops below
a lower threshold given by equation [2].
TEMP = ( T CRIT – T CRITHYS )
[2]
See Section 6.3 and Section 6.5 for ALERT / TACH pin functionality.
6.8
External Temperature Force Register
Table 6.8 External Diode Force Register
ADDR.
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
0Ch
R/W
External
Temperature Force
Sign
64
32
16
8
4
2
1
00h
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DATASHEET
SMSC EMC2101
SMBus Fan Control with 1°C Accurate Temperature Monitoring
Datasheet
The External Diode Force Register is used to force the Fan Control Look-Up Table to a specific fanspeed setting. When this function is enabled (see Section 6.16), the contents of this register are
compared against the temperature thresholds in the Fan Control Look-Up Table to determine the fan
setting to use.
The contents of this register represent temperature data in the same format as the data registers and
can be updated at any time.
The External Diode Temperature Registers are updated normally with the measured temperature and
compared against the THIGH and TCRIT limits normally but not used to determine the fan speed.
APPLICATION NOTE: This mode is used if the host or system requires temperature data from a source other than
the EMC2101 External Diode to be used for fan control.
6.9
One Shot Register
Table 6.9 One Shot Register
ADDR.
R/W
REGISTER
0Fh
W
One Shot
B7
B6
B5
B4
B3
B2
B1
B0
Writing to this register initiates a one shot update of the
temperature data. Data is not relevant and is not stored.
DEFAULT
00h
The One Shot Register initiates an update of the temperature measurements. This register can be
written at any time, however will only perform a one-shot conversion when the temperature monitoring
is in standby mode. When the one shot temperature conversion is complete the temperature data
registers are updated and the fan setting is updated if necessary. This register is self-clearing.
6.10
Scratchpad Registers
Table 6.10 Scratchpad Registers
ADDR.
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
11h
R/W
Scratchpad
B7
B6
B5
B4
B3
B2
B1
B0
00h
12h
R/W
Scratchpad
B7
B6
B5
B4
B3
B2
B1
B0
00h
The Scratchpad Registers are R/W registers that perform no function. They are included for software
compatibility.
6.11
Alert Mask Register
Table 6.11 Alert Mask Register
ADDR.
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
16h
R/W
Alert Mask
1
INT_
MSK
1
HIGH
MSK
LOW_
MSK
1
TCRIT_
MSK
TACH_
MSK
A4h
The Alert Mask Register enables interrupts from the temperature monitors and limits. Regardless of
the condition of the individual mask bits, the Status Register will be updated normally.
SMSC EMC2101
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SMBus Fan Control with 1°C Accurate Temperature Monitoring
Datasheet
Bit 6 - INT_MSK - Disables interrupts for the Internal Diode.
„
‘0’ (default) - The Internal Diode will generate an interrupt if its measured temperature exceeds the
Internal Diode high limit.
„
‘1’ - the Internal Diode will not generate interrupts.
Bit 4 - HIGH_MSK - Disables interrupts for the External Diode high limit.
„
‘0’ (default) - The External Diode will generate an interrupt if its measured temperature exceeds
the External Diode high limit.
„
‘1’ - the External Diode will not generate an interrupt when the high limit is exceeded.
Bit 3 - LOW_MSK - Disables interrupts for the External Diode low limit.
„
‘0’ (default) - The External Diode will generate an interrupt if its measured temperature drops below
the External Diode low limit.
„
‘1’ - the External Diode will not generate an interrupt when the temperature drops below the low
limit.
Bit 1 - TCRIT_MSK - Disables interrupts for the TCRIT Limit.
„
‘0’ (default) - An interrupt will be generated if the External Diode Temperature exceeds TCRIT.
„
‘1’ - An interrupt will not be generated if TCRIT is exceeded.
Bit 0 - TACH_MSK - Disables interrupts for the TACH Limit.
„
‘0’ (default) - An interrupted will be generated if the measured TACH value exceeds the TACH Limit
(indicating that the fan speed is too slow).
„
‘1’ - An interrupt will not be generated if the TACH limit is exceeded.
6.12
External Ideality Factor Register
Table 6.12 External Ideality Factor Register
ADDR.
R/W
REGISTER
B7
B6
17h
R/W
External
Ideality Factor
-
-
B5
B4
B3
B2
B1
IDCF[5:0]
B0
DEFAULT
12h
This register stores the ideality factor that is automatically applied to the external diode. The Ideality
factor is a 6 bit value that allows for a bi-directional trim centered on an ideality factor of 1.008.
Table 6.13 defines each setting and the corresponding Ideality factor.
Table 6.13 Ideality Factor Look-Up Table
SETTING
FACTOR
SETTING
FACTOR
SETTING
FACTOR
08h
0.9949
18h
1.0159
28h
1.0371
09h
0.9962
19h
1.0172
29h
1.0384
0Ah
0.9975
1Ah
1.0185
2Ah
1.0397
0Bh
0.9988
1Bh
1.0200
2Bh
1.0410
0Ch
1.0001
1Ch
1.0212
2Ch
1.0423
0Dh
1.0014
1Dh
1.0226
2Dh
1.0436
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SMSC EMC2101
SMBus Fan Control with 1°C Accurate Temperature Monitoring
Datasheet
Table 6.13 Ideality Factor Look-Up Table (continued)
SETTING
FACTOR
SETTING
FACTOR
SETTING
FACTOR
0Eh
1.0027
1Eh
1.0239
2Eh
1.0449
0Fh
1.0040
1Fh
1.0253
2Fh
1.0462
10h
1.0053
20h
1.0267
30h
1.0475
11h
1.0066
21h
1.0280
31h
1.0488
12h
1.0080
22h
1.0293
32h
1.0501
13h
1.0093
23h
1.0306
33h
1.0514
14h
1.0106
24h
1.0319
34h
1.0527
15h
1.0119
25h
1.0332
35h
1.0540
16h
1.0133
26h
1.0345
36h
1.0553
17h
1.0146
27h
1.0358
37h
1.0566
6.13
Beta Compensation Register
Table 6.14 Beta Compensation Register
ADDR.
R/W
REGISTER
B7
B6
B5
B4
B3
18h
R/W
Beta Compensation
-
-
-
-
ENABLE
B2
B1
B0
BETA[2:0]
DEFAULT
08h
This register is used to set the Beta Compensation factor that is used for the External Diode channel.
When using a diode-connected transistor (such as the 2N3904) or CPUs that implement the thermal
diode as a two-terminal diode, the CPU compensation circuit must be disabled by writing a value of
07h to this register.
Bit 3 - ENABLE - enables the Beta Compensation Factor Autodetection Algorithm
„
‘0’ - the Beta Compensation Factor Autodetection circuitry is disabled. The External Diode will
always use the Beta Compensation factor set by the BETA[2:0] bits.
„
‘1’ (default) - the Beta Compensation Factor Autodetection circuitry is enabled. At the beginning of
every conversion, the circuitry will determine the optimal Beta Compensation factor setting and use
the detected setting. The value of the BETA[2:0] bits will be ignored.
Bit 2-0 - BETA[2:0] - selects the Beta Compensation factor that the External Diode will use if the
autodetection circuitry is disabled. Table 6.15 shows the setting that should be used based on the
expected beta value of the substrate transistor connected to the External Diode channel.
Care should be taken when setting the BETA[2:0] bits. If the Beta Compensation factor is set at a beta
value that is higher than the transistor beta, then the circuit may introduce measurement errors.
SMSC EMC2101
39
DATASHEET
Revision 2.54 (06-16-09)
SMBus Fan Control with 1°C Accurate Temperature Monitoring
Datasheet
Table 6.15 CPU Beta Values
ENABLE
B2
B1
B0
0
0
0
0
0.11
0
0
0
1
0.18
0
0
1
0
0.25
0
0
1
1
0.33
0
1
0
0
0.43
0
1
0
1
1.00
0
1
1
0
2.33
0
1
1
1
Disabled
1
X
X
X
Automatic detection
6.14
MINIMUM BETA
TACH Reading Registers
Table 6.16 TACH Reading Registers
ADDR
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
46h
R
TACH Reading
Low Byte
TACH7
(128)
TACH6
(64)
TACH5
(32)
TACH4
(16)
TACH3
(8)
TACH2
(4)
TACH1
(2)
TACH0
(1)
FFh
47h
R
TACH Reading
High Byte
TACH15
(32768)
TACH14
(16384)
TACH13
(8192)
TACH12
(4096)
TACH11
(2048)
TACH10
(1024)
TACH9
(512)
TACH8
(256)
FFh
The TACH Registers hold the 16-bit TACH Reading. This reading represents the number of TACH
counts detected. The RPM of the fan can be determined by Equation [3] (see also Appendix B "TACH
Reference Table"). The bit weighting of each TACH[15:0] bit is shown in parenthesis after the value.
When determining the final fan speed, the TACH[15:0] bits need to be decoded into an equivalent
decimal number.
Where: TACH_COUNT is the
decimal representation of the
TACH[13:0] bits.
5, 400, 000
RPM = -------------------------------------------TACH _ COUNT
6.15
[3]
TACH Limit Registers
Table 6.17 TACH Reading Low Byte Register
ADDR
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
48h
R/W
TACH Limit
Low Byte
TACH_
L7
TACH_
L6
TACH_
L5
TACH_
L4
TACH_
L3
TACH_
L2
TACH_
L1
TACH_
L0
FFh
49h
R/W
TACH Limit
High Byte
TACH_
L15
TACH_
L14
TACH_
L13
TACH_
L12
TACH_
L11
TACH_
L10
TACH_
L9
TACH_
L8
FFh
Revision 2.54 (06-16-09)
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DATASHEET
SMSC EMC2101
SMBus Fan Control with 1°C Accurate Temperature Monitoring
Datasheet
The TACH Limit Registers store the maximum TACH count that the fan is expected to operate at.
TACH count is inversely proportional to the actual fan speed. This limit is used to guarantee that the
fan has spun up properly. If the measured TACH is higher than this limit (indicating that the fan speed
is lower than the minimum RPM value), then the TACH bit is set in the Status Register.
Additionally if the measured TACH count exceeds this limit, depending on the status of the
TACH_M[1:0] bits (see Section 6.16), the TACH reading registers may be forced to FFFFh.
6.16
Fan Configuration Register
Table 6.18 Fan Configuration Register
ADDR.
R/W
REGISTER
B7
B6
B5
B4
B3
B2
4Ah
R/W
Fan Config
-
FORCE
PROG
POLARITY
CLK_
SEL
CLK_
OVR
B1
B0
DEFAULT
TACH_M[1:0]
20h
The Fan Configuration Register enables the Fan Control Look-Up Table and polarity of the PWM signal
driving the output.
Bit 6 - FORCE - enables the External Temperature Force Register. This bit is not used if the Fan
Control Look-Up Table is not used.
„
‘0’ (default) - the External Diode Force Register is not used. The measured External Diode
temperature is used to determine the position in the Fan Control Look-Up Table.
„
‘1’ - the External Temperature Force Register is used. When determining the position in the Fan
Control Look-Up Table, the contents of the External Temperature Force Register will be used
instead of the measured External Diode temperature. All limits will be checked against the
measured External Diode temperature as normal.
Bit 5 - PROG - enables the Fan Control Look-Up Table for update and sets fan driver output based
on Fan Control Look-Up Table values.
„
‘0’ - the Fan Setting Register and Fan Control Look-Up Table Registers are read-only and the Fan
Control Look-Up Table Registers will be used.
„
‘1’ (default) - the Fan Setting Register and Fan Control Look-Up Table Registers can be written.
The value written into the Fan Setting Register will be instantly applied to the fan driver and the
Fan Control Look-Up Table will not be used.
Bit 4 - POLARITY- sets the polarity of the Fan output driver. For the EMC2101-R, the value of this bit
is determined by the value of the pull-up resistor on the ALERT / TACH pin (see Table 5.1). When the
PWM default value is set at 100% duty cycle, the default value is set to ‘1’ and when the PWM default
value is set to 0% duty cycle, the default value is set to ‘0’. This occurs within 10ms after power-up.
„
‘0’ (default - EMC2101) - The polarity of the Fan output driver is non-inverted. A ‘00h’ setting will
correspond to a 0% duty cycle or minimum DAC output voltage.
„
‘1’ - The polarity of the Fan output driver is inverted. A ‘00h’ setting will correspond to a 100% duty
cycle or maximum DAC output voltage.
Bit 3 - CLK_SEL - Determines the base clock that is used to determine the final PWM frequency.
„
‘0’ (default) - The base clock that is used to determine the PWM frequency is 360kHz.
„
‘1’ - The base clock that is used to determine the PWM frequency is 1.4kHz.
Bit 2 - CLK_OVR - Overrides the CLK_SEL bit and uses the Frequency Divide Register to determine
the base PWM frequency. It is recommended that this bit be set for maximum PWM resolution.
„
‘0’ (default) - The base clock frequency for the PWM is determined by the CLK_SEL bit.
„
‘1’ (recommended) - The base clock that is used to determine the PWM frequency is set by the
Frequency Divide Register
SMSC EMC2101
41
DATASHEET
Revision 2.54 (06-16-09)
SMBus Fan Control with 1°C Accurate Temperature Monitoring
Datasheet
Bit 1-0 - TACH_M[1:0] - Determines the basic operation of the tachometer input as shown in
Table 6.19.
Table 6.19 TACH Modes
TACH_M[1]
TACH_M[0]
0
TACH MODE
False readings when under minimum
detectable RPM (TACH Limit).
0
(Default condition - See Note 6.2)
0
1
1
0
1
1
Note 6.2
6.17
FFFFh reading when under minimum
detectable RPM.
When the PWM base clock is set at 360kHz mode 00b is used regardless of the setting
of the TACH_M[1:0] bits.
Fan Spin Up Configuration Register
Table 6.20 Fan Spin Up Configuration Register
ADDR.
R/W
REGISTER
B7
B6
B5
4Bh
R/W
Fan Spin Up
Config
-
-
FAST_
TACH
B4
B3
SPIN_DRIVE[1:0]
B2
B1
B0
SPIN_TIME[2:0]
DEFAULT
3Fh
The Fan Spin Up Configuration register controls the spin-up behavior of the device. The Fan driver
enters its spin-up routine any time it transitions from a minimum fan setting (00h) to a higher fan setting
(but does not invoke the spin-up routine upon power up). Once the spin-up time has been met, the
fan driver is reduced to the programmed setting.
Bit 5 - FAST_TACH - Determines whether the Spin-Up routine aborts when the measured TACH is less
than the TACH Limit.
„
‘0’ - The Spin-Up routine uses the duty cycle and spin-up time independently of the TACH reading.
„
‘1’ (default) - The Spin-Up routine will abort when the TACH measurement is less than the TACH
Limit or the programmed Spin-Up time is met, whichever is less. In this case, the SPIN_DRIVE[1:0]
bits are ignored and the drive will always be at 100%.
APPLICATION NOTE: This bit will be ignored if the ALT_TCH bit in the Configuration Register (see Section 6.5) is
set to ‘0’.
APPLICATION NOTE: If the SPIN_TIME[2:0] bits are set at 000b, then the Spin-Up Routine is bypassed regardless
of the status of this bit.
Bit 4 - 3 SPIN_DRIVE[1:0] - Determines the setting of the drive circuit during the Spin-Up routine
according to Table 6.21.
Revision 2.54 (06-16-09)
42
DATASHEET
SMSC EMC2101
SMBus Fan Control with 1°C Accurate Temperature Monitoring
Datasheet
Table 6.21 Spin-Up Drive
SPIN_DRIVE[1:0]
1
0
SPIN UP DRIVE
0
0
0 - Spin-Up Cycle bypassed
0
1
50% (half drive)
1
0
75% (3/4 drive)
1
1
100% (full drive) (default)
Bit 2-0 - SPIN_TIME[2:0] - determines the length of time that the fan drive will remain at the
SPIN_DRIVE[1:0] setting as shown in Table 6.22.
Table 6.22 Spin-Up Time
SPIN_TIME[2:0]
6.18
2
1
0
SPIN UP TIME
0
0
0
0 - Spin-Up Cycle bypassed
0
0
1
0.05 sec.
0
1
0
0.1 sec.
0
1
1
0.2 sec.
1
0
0
0.4 sec.
1
0
1
0.8 sec.
1
1
0
1.6 sec.
1
1
1
3.2 sec. (default)
Fan Setting Register
Table 6.23 Fan Setting Register
ADDR.
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
4Ch
R/W
(see
text)
Fan Setting
-
-
32
16
8
4
2
1
00h
The Fan Setting Register drives the fan driver when the Fan Control Look-Up Table is not used (see
Section 6.16). Any data written to the Fan Setting registers is applied immediately to the fan driver
(PWM or DAC). When the Fan Control Look-Up Table is being used, any writes to this register will be
ignored. If the Fan Control Look-Up Table is disabled, then the fan drive will be set at the last value
that was used by the Fan Control Look-Up Table.
When the Fan Control Look-Up Table Registers are being used, the register is read-only.
SMSC EMC2101
43
DATASHEET
Revision 2.54 (06-16-09)
SMBus Fan Control with 1°C Accurate Temperature Monitoring
Datasheet
The register applies to the fan driver in both PWM and DAC operating modes. The DAC output is
determined by equation [4] below.
FAN _ SETTING
FAN = ⎛⎝ --------------------------------------------⎞⎠ × V DD
64
[4]
These values are independent of the POLARITY bit (see Section 6.16). Therefore, a value of 00h in
the Fan Setting Register will always refer to minimum output drive while a setting of 3Fh in the Fan
Setting Register will always refer to maximum output drive.
APPLICATION NOTE: The output of the DAC driver is dependent upon the current load. With a low current load,
the output will be from 0V to an LSB (approximately 52mV at VDD = 3.3V) below VDD with
a maximum of 64 linear steps.
6.19
PWM Frequency Register
Table 6.24 PWM Frequency Register
ADDR.
R/W
REGISTER
B7
B6
B5
4Dh
R/W
PWM Frequency
-
-
-
B4
B3
B2
B1
B0
PWM_F[4:0]
DEFAULT
17h
The PWM Frequency Register determines the final PWM frequency and “effective resolution” of the
PWM driver. It has no affect on the DAC output resolution.
It is recommended that this register be set at 1Fh for maximum resolution. See Appendix A "Advanced
PWM Options" for full operation of the PWM_F register and its interactions with the PWM Resolution
and Duty Cycle.
6.20
PWM Frequency Divide Register
Table 6.25 PWM Frequency Divide Register
ADDR.
R/W
REGISTER
4Eh
R/W
PWM Frequency
Divide
B7
B6
B5
B4
B3
PWM_D[7:0]
B2
B1
B0
DEFAULT
01h
This register holds an alternate PWM Frequency divide value that can be used instead of the CLK_SEL
bit function. This register can be written at any time, however unless the CLK_OVR bit is set to a logic
‘1’, it is not used.
When the CLK_OVR bit is set to a logic ‘1’, the PWM Frequency Divide Register is used in conjunction
with the PWM Frequency Register to determine the final PWM frequency that the load will see. When
the CLK_OVR bit is set to a logic ‘0’, the setting of this register is not changed and is not used to
determine the effective PWM frequency.
The PWM frequency when the PWM Frequency Divide Register is used is shown in Equation [5].
Revision 2.54 (06-16-09)
44
DATASHEET
SMSC EMC2101
SMBus Fan Control with 1°C Accurate Temperature Monitoring
Datasheet
Where:
PWM_F is the setting of the PWM
Frequency register (4Dh)
360 k
1
5806
PWM _ D = ⎛ --------------------------------⎞ × ----------------- = ----------------⎝ 2 × PWM _ F⎠ FREQ
FREQ
PWM_D is the setting of the PWM
Frequency Divide Register (4Eh)
[5]
FREQ is the desired PWM
Frequency
Maximum resolution is achieved by setting the PWM Frequency Register to 1Fh. With maximum
resolution, the desired PWM frequency can be achieved by adjusting the PWM Frequency Divide
Register setting (PWM_D[7:0]) as shown in Table 6.26.
For example, if the user desires a 30Hz PWM frequency with maximum PWM resolution, then the
PWM_F[4:0] bits should be set at 1Fh (31d) and the PWM_D bits should be set at C1h (193d).
Table 6.26 Examples of Fan PWM Frequency with Maximum Resolution
PWM_F[4:0] = 1Fh
PWM_D[7:0]
SETTING
EFFECTIVE
RESOLUTION
(%)
EFFECTIVE
DUTY CYCLE
(AT 50%
FAN_SETTING)
EFFECTIVE
DUTY CYCLE
(AT 75%
FAN_SETTING)
FAN_SETTING
TO GET 75%
DUTY CYCLE
EFFECTIVE PWM
FREQUENCY (HZ)
01h
1.61
51.6%
77.4%
2Eh (74.2%)
5806.5
11h
1.61
51.6%
77.4%
2Eh (74.2%)
341.6
20h
1.61
51.6%
77.4%
2Eh (74.2%)
181.5
47h
1.61
51.6%
77.4%
2Eh (74.2%)
81.8
C0
1.61
51.6%
77.4%
2Eh (74.2%)
30.2
C1
1.61
51.6%
77.4%
2Eh (74.2%)
30.0
FFh
1.61
51.6%
77.4%
2Eh (74.2%)
22.7
6.21
Fan Control Look-Up Table Hysteresis Register
Table 6.27 Look Up Table Hysteresis Register
ADDR.
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
4Fh
R/W
Fan Control LookUp Table Hysteresis
-
-
-
16
8
4
2
1
04h
(4°C)
The Fan Control Look-Up Table Hysteresis Register determines the amount of hysteresis applied to
the temperature inputs of the fan control Fan Control Look-Up Table. See Section 5.6.4.
SMSC EMC2101
45
DATASHEET
Revision 2.54 (06-16-09)
SMBus Fan Control with 1°C Accurate Temperature Monitoring
Datasheet
6.22
Fan Control Look-Up Table Registers
Table 6.28 Fan Control Look Up Table Registers
ADDR.
R/W
Note 6.3
50h
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
R/W
Fan Control LookUp Table T1
0
64
32
16
8
4
2
1
7Fh
51h
R/W
Fan Control LookUp Table S1
-
-
32
16
8
4
2
1
3Fh
52h
R/W
Fan Control LookUp Table T2
0
64
32
16
8
4
2
1
7Fh
53h
R/W
Fan Control LookUp Table S2
-
-
32
16
8
4
2
1
3Fh
54h
R/W
Fan Control LookUp Table T3
0
64
32
16
8
4
2
1
7Fh
55h
R/W
Fan Control LookUp Table S3
-
-
32
16
8
4
2
1
3Fh
56h
R/W
Fan Control LookUp Table T4
0
64
32
16
8
4
2
1
7Fh
57h
R/W
Fan Control LookUp Table S4
-
-
32
16
8
4
2
1
3Fh
58h
R/W
Fan Control LookUp Table T5
0
64
32
16
8
4
2
1
7Fh
59h
R/W
Fan Control LookUp Table S5
-
-
32
16
8
4
2
1
3Fh
5Ah
R/W
Fan Control LookUp Table T6
0
64
32
16
8
4
2
1
7Fh
5Bh
R/W
Fan Control LookUp Table S6
-
-
32
16
8
4
2
1
3Fh
5Ch
R/W
Fan Control LookUp Table T7
0
64
32
16
8
4
2
1
7Fh
5Dh
R/W
Fan Control LookUp Table S7
-
-
32
16
8
4
2
1
3Fh
5Eh
R/W
Fan Control LookUp Table T8
0
64
32
16
8
4
2
1
7Fh
5Fh
R/W
Fan Control LookUp Table S8
-
-
32
16
8
4
2
1
3Fh
Note 6.3
Revision 2.54 (06-16-09)
When the PROG bit in the Fan Configuration Register (see Section 6.16) is set to ‘0’, these
registers become read only.
46
DATASHEET
SMSC EMC2101
SMBus Fan Control with 1°C Accurate Temperature Monitoring
Datasheet
The table should be loaded with the lowest temperature in the T1 register (50h) and increasing in
temperature for all settings.
See Section 5.6.4 for description of the Fan Control Look Up Table operation. The fan speed settings
for each temperature threshold follow the same behavior as the Fan Setting Register (see
Section 6.18).
6.23
Averaging Filter Register
Table 6.29 Averaging Filter Register
ADDR.
R/W
REGISTER
B7
B6
B5
B4
B3
BFh
R/W
Averaging Filter
-
-
-
-
-
B2
B1
FILTER[1:0]
B0
DEFAULT
ALERT_
COMP
00h
The Averaging Filter Register controls the level of digital averaging that is used for the External Diode
temperature measurements as well as the configuration of the ALERT / TACH pin functionality.
Bit 2 - 1 - FILTER[1:0] - control the level of digital filtering that is applied to the External Diode
temperature measurements as shown in Table 6.30. See Figure 5.5 and Figure 5.6 for examples on
the filter behavior.
Table 6.30 Averaging Settings
FILTER[1:0]
1
0
AVERAGING
0
0
Disabled (default)
0
1
Level 1
1
0
Level 1
1
1
Level 2
Bit 0 - ALERT_COMP - determines the functionality of the ALERT / TACH pin.
„
‘0’ (default) - the ALERT / TACH pin is configured to act as an interrupt (see Section 5.4.2).
„
‘1’ - the ALERT / TACH pin is configured to operate as a temperature comparator (see
Section 5.4.1).
SMSC EMC2101
47
DATASHEET
Revision 2.54 (06-16-09)
SMBus Fan Control with 1°C Accurate Temperature Monitoring
Datasheet
6.24
Product ID Register
Table 6.31 Product ID Register
ADDR
.
FDh
R/W
REGISTER
Product ID
Register
R
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
0
0
0
1
0
1
1
0
16h
(EMC2101)
0
0
1
0
1
0
0
0
28h
(EMC2101-R)
The Product ID Register contains a unique 8 bit word that identifies the product.
6.25
Manufacturer ID Register (FEh)
Table 6.32 Manufacturer ID Register
ADDR.
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
FEh
R
SMSC ID
Register
0
1
0
1
1
1
0
1
5Dh
The Manufacturer ID register contains an 8 bit word that identifies the SMSC as the manufacturer of
the EMC2101.
6.26
Revision Register (FFh)
Table 6.33 Revision Register
ADDR.
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
FFh
R
Revision Register
0
0
0
0
0
0
0
1
01h
The Revision register contains an 8 bit word that identifies the die revision.
Revision 2.54 (06-16-09)
48
DATASHEET
SMSC EMC2101
REVISION HISTORY
REVISION
3
D
PIN 1 IDENTIFIER
AREA (D/2 X E1/2)
e
3
DESCRIPTION
-
DATE
RELEASED BY
-
-
SEE SPEC FRONT PAGE FOR REVISION HISTORY
5
c
E
E1
SEE DETAIL "A"
2 8X b
END VIEW
TOP VIEW
49
DATASHEET
A2
A
C
SEATING PLANE
A1
ccc C
SIDE VIEW
3-D VIEW
H
C
GAUGE PLANE
0.25
SEATING PLANE
0° - 8°
NOTES:
1. ALL DIMENSIONS ARE IN MILLIMETER.
2. TOLERANCE ON THE TRUE POSITION OF THE LEADS IS ± 0.065mm MAXIMUM.
3. PACKAGE BODY DIMENSIONS "D" AND "E1" DO NOT INCLUDE MOLD PROTRUSIONS OR FLASH.
MAXIMUM MOLD PROTRUSIONS OR FLASH IS 0.15 mm (0.006 INCHES) PER END AND SIDE.
DIMENSIONS "D" AND "E1" ARE DETERMINED AT DATUM PLANE "H".
4. DIMENSION FOR FOOT LENGTH "L" IS MEASURED AT THE GAUGE PLANE 0.25mm ABOVE THE
SEATING PLANE.
5. DETAILS OF PIN 1 IDENTIFIER ARE OPTIONAL, BUT MUST BE LOCATED WITHIN THE ZONE
INDICATED.
4
L
UNLESS OTHERWISE SPECIFIED
DIMENSIONS ARE IN MILLIMETERS
AND TOLERANCES ARE:
L1
DETAIL "A"
DECIMAL
±0.1
X.X
X.XX ±0.05
X.XXX ±0.025
THIRD ANGLE PROJECTION
80 ARKAY DRIVE
HAUPPAUGE, NY 11788
USA
ANGULAR
±1°
TITLE
NAME
DIM AND TOL PER ASME Y14.5M - 1994
MATERIAL
SMSC EMC2101
SCALE: 3/1
FINISH
-
PRINT WITH "SCALE TO FIT"
DO NOT SCALE DRAWING
DATE
PACKAGE OUTLINE
8 PIN TSSOP, 3x3 MM BODY, 0.65 MM PITCH
DRAWN
S.K.ILIEV
7/05/04
CHECKED
S.K.ILIEV
DWG NUMBER
S.K.ILIEV
Figure 9.1 8-PIN MSOP / TSSOP Package
SCALE
7/07/04
REV
MO-8-TSSOP-3x3
7/05/04
APPROVED
STD COMPLIANCE
1:1
JEDEC: MO-187 / D
D
SHEET
1 OF 1
SMBus Fan Control with 1°C Accurate Temperature Monitoring
Datasheet
Revision 2.54 (06-16-09)
Chapter 7 Package Diagrams
SEE DETAIL "A"
3
D
DESCRIPTION
A
INITIAL RELEASE
DATE
RELEASED BY
7/07/04
S.K.ILIEV
e
8
E1
E
2
4
INDEX AREA
(D/2 X E1/2)
2
8X b
c
4
END VIEW
TOP VIEW
50
DATASHEET
1
5
C
A2
SEATING PLANE
A
A1
ccc C
SIDE VIEW
3-D VIEW
NOTES:
1. ALL DIMENSIONS ARE IN MILLIMETER.
2. TRUE POSITION SPREAD TOLERANCE IS ± 0.125mm AT MAXIMUM MATERIAL CONDITION.
3. PACKAGE BODY DIMENSION "D" DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR
GATE BURRS. MAXIMUM MOLD FLASH, PROTRUSIONS OR GATE BURRS IS 0.15 mm PER
END. DIMENSION "E1" DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSION.
MAXIMUM INTERLEAD FLASH OR PROTRUSION IS 0.25 mm PER SIDE. "D1" & "E1"
DIMENSIONS ARE DETERMINED AT DATUM PLANE "H".
4. DIMENSIONS "b" & "c" APPLY TO THE FLAT SECTION OF THE LEAD BETWEEN 0.10 TO
0.25 mm FROM THE LEAD TIP.
5. THE CHAMFER FEATURE IS OPTIONAL. IF IT IS NOT PRESENT, THEN A PIN 1 IDENTIFIER
MUST BE LOCATED WITHIN THE INDEX AREA INDICATED.
H
0.25
GAUGE PLANE
L
L1
DETAIL "A"
SCALE: 3/1
0
UNLESS OTHERWISE SPECIFIED
DIMENSIONS ARE IN MILLIMETERS
AND TOLERANCES ARE:
DECIMAL
X.X
±0.1
X.XX ±0.05
X.XXX ±0.025
THIRD ANGLE PROJECTION
80 ARKAY DRIVE
HAUPPAUGE, NY 11788
USA
ANGULAR
±1°
TITLE
NAME
DIM AND TOL PER ASME Y14.5M - 1994
MATERIAL
FINISH
-
PRINT WITH "SCALE TO FIT"
DO NOT SCALE DRAWING
DATE
DRAWN
S.K.ILIEV
7/07/04
DWG NUMBER
CHECKED
S.K.ILIEV
Figure 9.2 8-PIN SOIC Package
SCALE
7/07/04
REV
MO-8-SOIC-4.9x3.9
7/07/04
APPROVED
S.K.ILIEV
PACKAGE OUTLINE
8 PIN SOIC, 3.9mm BODY WIDTH, 1.27mm PITCH
STD COMPLIANCE
1:1
JEDEC: MS-012 / AA
A
SHEET
1 OF 1
SMSC EMC2101
3
Revision 2.54 (06-16-09)
Datasheet
SMBus Fan Control with 1°C Accurate Temperature Monitoring
REVISION HISTORY
REVISION
SMBus Fan Control with 1°C Accurate Temperature Monitoring
Datasheet
Appendix A Advanced PWM Options
The PWM Frequency Register determines the number of clocks (set by the CLK_SEL bit or the
PWM_D register settings) represent 1/2 of the period of the final PWM output waveform. Therefore,
as the PWM Frequency Register is updated, the PWM frequency is likewise updated. However, it also
directly affects the PWM Resolution and PWM duty cycle.
The PWM frequency is set according to Equation [8] or Equation [9] below or, if the PWM Divide
Register is used, Equation [5] (see Section 6.20, "PWM Frequency Divide Register," on page 44).
The PWM Frequency Register does not affect the Fan Setting (either the Fan Setting Register or the
Fan Setting entries in the Fan Control Look-up Table Registers).
The Fan Setting Register determines the number of clocks that the PWM output is high for is always
based on 64 time steps for a PWM cycle. As the PWM Frequency Register changes (or the Fan Setting
changes) the effective duty cycle will vary according to Equation [6] and the PWM resolution will vary
according to Equation [7]. This is a result of the “on” time determined by Fan Setting changing with
respect to the overall PWM period determined by the PWM Frequency Register.
APPLICATION NOTE: If the Fan Setting is set at a value that is higher than 2x the PWM Frequency Register
settings, the PWM output will be at 100% duty cycle.
Table A.1 shows the effective resolution, duty cycle, and frequency as the PWM Frequency Register
setting is changed.
FAN _ SETTING
EFFECTIVE _ DUTY _ CYCLE = ⎛ --------------------------------------------⎞ × 100%
⎝ PWM _ F × 2 ⎠
Where: PWM_F is the setting of the PWM
Frequency Register (4Dh)
[6]
100%
EFFECTIVE _ RESOLUTION = -------------------------------PWM _ F × 2
Where: PWM_F is the setting of the PWM
Frequency Register (4Dh)
[7]
Where: PWM_F is the setting of the
PWM Frequency register (4Dh)
PWM_D is the setting of the PWM
Frequency Divide Register (4Eh)
360 k
PWM _ FREQUENCY = ----------------------------2 xPWM _F
[8]
CLK_SEL = ‘0’
1.4 k
PWM _ FREQUENCY = ----------------------------2 xPWM _F
SMSC EMC2101
CLK_SEL = ‘1’
51
DATASHEET
[9]
Revision 2.54 (06-16-09)
EFFECTIVE DUTY
CYCLE (AT 75%
FAN_SETTING)
FAN_SETTING
TO GET 75%
DUTY CYCLE
PWM FREQUENCY
AT 360KHZ BASE
FREQUENCY (KHZ)
PWM FREQUENCY AT
1.4KHZ BASE
FREQUENCY (HZ)
Setting 00h is mapped to setting 01h
01h
50.00
100%
100%
01h (50%)
180.0
704.2
02h
25.00%
100%
100%
03h (75%)
90.0
350.0
03h
16.67%
100%
100%
04h (66.7%)
60.0
233.3
04h
12.50%
100%
100%
06h (75%)
45.0
175.0
05h
10.00%
100%
100%
07h (70%)
36.0
140.0
06h
8.33%
100%
100%
09h (75%)
30.0
116.7
07h
7.14%
100%
100%
0Ah (71.4%)
25.7
100.0
08h
6.25%
100%
100%
0Ch (75%)
22.5
87.5
09h
5.56%
100%
100%
0Dh (72.5)
20.0
77.8
0Ah
5.00%
100%
100%
0Fh (75%)
18.0
70.0
0Bh
4.54%
100%
100%
11h (77.3%)
16.4
63.7
0Ch
4.17%
100%
100%
12h (75%)
15.0
58.3
0Dh
3.84%
100%
100%
14h (76.9%)
13.8
53.8
0Eh
3.57%
100%
100%
15h (75%)
12.8
50.0
0Fh
3.33%
100%
100%
16h (73.3%)
12.0
46.7
10h
3.13
100%
100%
18h (75.0%)
11.25
44.0
11h
2.94
100%
94.1%
19h (73.5%)
10.68
41.4
12h
2.78
100%
88.9%
1Bh (75.0%)
10.00
39.1
13h
2.63
100%
84.2%
1Ch (73.7%)
9.47
37.1
52
DATASHEET
00h
EFFECTIVE
DUTY CYCLE (AT
50%
FAN_SETTING)
SMSC EMC2101
PWM_F [4:0]
SETTING
EFFECTIVE
RESOLUTION
(%)
Revision 2.54 (06-16-09)
Datasheet
SMBus Fan Control with 1°C Accurate Temperature Monitoring
Table A.1 Fan Effective Duty Cycle Resolution and Frequency
EFFECTIVE DUTY
CYCLE (AT 75%
FAN_SETTING)
EFFECTIVE
DUTY CYCLE (AT
50%
FAN_SETTING)
FAN_SETTING
TO GET 75%
DUTY CYCLE
PWM FREQUENCY
AT 360KHZ BASE
FREQUENCY (KHZ)
PWM FREQUENCY AT
1.4KHZ BASE
FREQUENCY (HZ)
14h
2.50
100%
80.0%
1Eh (75.0%)
9.00
35.2
15h
2.38
100%
76.2%
1Fh (73.8%)
8.57
33.5
16h
2.27
100%
72.7%
21h (75.0%)
8.18
32.0
17h
2.17
100%
69.7%
22h (73.9%)
7.83
30.6
18h
2.08
100%
66.7%
24h (75.0%)
7.50
29.3
19h
2.00
96%
64.0%
25h (74.0%)
7.20
28.2
1Ah
1.92
92.3%
61.5%
27h (75.0%)
6.92
27.1
1Bh
1.85
88.9%
59.3%
28h (74.1%)
6.67
26.1
1Ch
1.79
85.7%
57.1%
2Ah (75.0%)
6.43
25.1
1Dh
1.72
82.8%
55.2%
2Bh (74.1%)
6.21
24.3
1Eh
1.67
80.0%
53.3%
2Dh (75.0%)
6.00
23.5
1Fh
1.61
77.4%
51.6%
2Eh (74.2%)
5.81
22.7
SMBus Fan Control with 1°C Accurate Temperature Monitoring
53
DATASHEET
PWM_F [4:0]
SETTING
EFFECTIVE
RESOLUTION
(%)
Datasheet
Revision 2.54 (06-16-09)
Table A.1 Fan Effective Duty Cycle Resolution and Frequency (continued)
SMSC EMC2101
HEX
RPM
DEC
HEX
RPM
DEC
HEX
RPM
DEC
HEX
RPM
DEC
HEX
RPM
DEC
HEX
RPM
512
200h
10547
1280
500h
4219
2048
800h
2637
2816
B00h
1918
3584
E00h
1507
4352
1100h
1241
528
210h
10227
1296
510h
4167
2064
810h
2616
2832
B10h
1907
3600
E10h
1500
4368
1110h
1236
544
220h
9926
1312
520h
4116
2080
820h
2596
2848
B20h
1896
3616
E20h
1493
4384
1120h
1232
560
230h
9643
1328
530h
4066
2096
830h
2576
2864
B30h
1885
3632
E30h
1487
4400
1130h
1227
576
240h
9375
1344
540h
4018
2112
840h
2557
2880
B40h
1875
3648
E40h
1480
4416
1140h
1223
592
250h
9122
1360
550h
3971
2128
850h
2538
2896
B50h
1865
3664
E50h
1474
4432
1150h
1218
608
260h
8882
1376
560h
3924
2144
860h
2519
2912
B60h
1854
3680
E60h
1467
4448
1160h
1214
624
270h
8654
1392
570h
3879
2160
870h
2500
2928
B70h
1844
3696
E70h
1461
4464
1170h
1210
640
280h
8438
1408
580h
3835
2176
880h
2482
2944
B80h
1834
3712
E80h
1455
4480
1180h
1205
656
290h
8232
1424
590h
3792
2192
890h
2464
2960
B90h
1824
3728
E90h
1448
4496
1190h
1201
672
2A0h
8036
1440
5A0h
3750
2208
8A0h
2446
2976
BA0h
1815
3744
EA0h
1442
4512
11A0h
1197
688
2B0h
7849
1456
5B0h
3709
2224
8B0h
2428
2992
BB0h
1805
3760
EB0h
1436
4528
11B0h
1193
704
2C0h
7670
1472
5C0h
3668
2240
8C0h
2411
3008
BC0h
1795
3776
EC0h
1430
4544
11C0h
1188
720
2D0h
7500
1488
5D0h
3629
2256
8D0h
2394
3024
BD0h
1786
3792
ED0h
1424
4560
11D0h
1184
736
2E0h
7337
1504
5E0h
3590
2272
8E0h
2377
3040
BE0h
1776
3808
EE0h
1418
4576
11E0h
1180
752
2F0h
7181
1520
5F0h
3553
2288
8F0h
2360
3056
BF0h
1767
3824
EF0h
1412
4592
11F0h
1176
768
300h
7031
1536
600h
3516
2304
900h
2344
3072
C00h
1758
3840
F00h
1406
4608
1200h
1172
784
310h
6888
1552
610h
3479
2320
910h
2328
3088
C10h
1749
3856
F10h
1400
4624
1210h
1168
800
320h
6750
1568
620h
3444
2336
920h
2312
3104
C20h
1740
3872
F20h
1395
4640
1220h
1164
816
330h
6618
1584
630h
3409
2352
930h
2296
3120
C30h
1731
3888
F30h
1389
4656
1230h
1160
Revision 2.54 (06-16-09)
DEC
54
DATASHEET
Table B.1 Example TACH Decode 10k RPM to 1k RPM
SMSC EMC2101
Datasheet
SMBus Fan Control with 1°C Accurate Temperature Monitoring
Appendix B TACH Reference Table
SMSC EMC2101
HEX
RPM
DEC
HEX
RPM
DEC
HEX
RPM
DEC
HEX
RPM
DEC
HEX
RPM
DEC
HEX
RPM
832
340h
6490
1600
640h
3375
2368
940h
2280
3136
C40h
1722
3904
F40h
1383
4672
1240h
1156
848
350h
6368
1616
650h
3342
2384
950h
2265
3152
C50h
1713
3920
F50h
1378
4688
1250h
1152
864
360h
6250
1632
660h
3309
2400
960h
2250
3168
C60h
1705
3936
F60h
1372
4704
1260h
1148
880
370h
6136
1648
670h
3277
2416
970h
2235
3184
C70h
1696
3952
F70h
1366
4720
1270h
1144
896
380h
6027
1664
680h
3245
2432
980h
2220
3200
C80h
1688
3968
F80h
1361
4736
1280h
1140
912
390h
5921
1680
690h
3214
2448
990h
2206
3216
C90h
1679
3984
F90h
1355
4752
1290h
1136
928
3A0h
5819
1696
6A0h
3184
2464
9A0h
2192
3232
CA0h
1671
4000
FA0h
1350
4768
12A0h
1133
944
3B0h
5720
1712
6B0h
3154
2480
9B0h
2177
3248
CB0h
1663
4016
FB0h
1345
4784
12B0h
1129
960
3C0h
5625
1728
6C0h
3125
2496
9C0h
2163
3264
CC0h
1654
4032
FC0h
1339
4800
12C0h
1125
976
3D0h
5533
1744
6D0h
3096
2512
9D0h
2150
3280
CD0h
1646
4048
FD0h
1334
4816
12D0h
1121
992
3E0h
5444
1760
6E0h
3068
2528
9E0h
2136
3296
CE0h
1638
4064
FE0h
1329
4832
12E0h
1118
1008
3F0h
5357
1776
6F0h
3041
2544
9F0h
2123
3312
CF0h
1630
4080
FF0h
1324
4848
12F0h
1114
1024
400h
5273
1792
700h
3013
2560
A00h
2109
3328
D00h
1623
4096
1000h
1318
4864
1300h
1110
1040
410h
5192
1808
710h
2987
2576
A10h
2096
3344
D10h
1615
4112
1010h
1313
4880
1310h
1107
1056
420h
5114
1824
720h
2961
2592
A20h
2083
3360
D20h
1607
4128
1020h
1308
4896
1320h
1103
1072
430h
5037
1840
730h
2935
2608
A30h
2071
3376
D30h
1600
4144
1030h
1303
4912
1330h
1099
1088
440h
4963
1856
740h
2909
2624
A40h
2058
3392
D40h
1592
4160
1040h
1298
4928
1340h
1096
1104
450h
4891
1872
750h
2885
2640
A50h
2045
3408
D50h
1585
4176
1050h
1293
4944
1350h
1092
1120
460h
4821
1888
760h
2860
2656
A60h
2033
3424
D60h
1577
4192
1060h
1288
4960
1360h
1089
1136
470h
4754
1904
770h
2836
2672
A70h
2021
3440
D70h
1570
4208
1070h
1283
4976
1370h
1085
1152
480h
4688
1920
780h
2813
2688
A80h
2009
3456
D80h
1563
4224
1080h
1278
4992
1380h
1082
1168
490h
4623
1936
790h
2789
2704
A90h
1997
3472
D90h
1555
4240
1090h
1274
5008
1390h
1078
1184
4A0h
4561
1952
7A0h
2766
2720
AA0h
1985
3488
DA0h
1548
4256
10A0h
1269
5024
13A0h
1075
1200
4B0h
4500
1968
7B0h
2744
2736
AB0h
1974
3504
DB0h
1541
4272
10B0h
1264
5040
13B0h
1071
SMBus Fan Control with 1°C Accurate Temperature Monitoring
55
DATASHEET
DEC
Datasheet
Revision 2.54 (06-16-09)
Table B.1 Example TACH Decode 10k RPM to 1k RPM (continued)
RPM
DEC
HEX
RPM
DEC
HEX
RPM
DEC
HEX
RPM
DEC
HEX
RPM
DEC
HEX
RPM
1216
4C0h
4441
1984
7C0h
2722
2752
AC0h
1962
3520
DC0h
1534
4288
10C0h
1259
5056
13C0h
1068
1232
4D0h
4383
2000
7D0h
2700
2768
AD0h
1951
3536
DD0h
1527
4304
10D0h
1255
5072
13D0h
1065
1248
4E0h
4327
2016
7E0h
2679
2784
AE0h
1940
3552
DE0h
1520
4320
10E0h
1250
5088
10E0h
1061
1264
4F0h
4272
2032
7F0h
2657
2800
AF0h
1929
3568
DF0h
1513
4336
10F0h
1245
5104
13F0h
1058
Revision 2.54 (06-16-09)
HEX
56
DATASHEET
DEC
SMSC EMC2101
Datasheet
SMBus Fan Control with 1°C Accurate Temperature Monitoring
Table B.1 Example TACH Decode 10k RPM to 1k RPM (continued)
SMBus Fan Control with 1°C Accurate Temperature Monitoring
Datasheet
Revision History
Customer Revision History
REVISION LEVEL & DATE
Revision 2.54 (06-16-09)
SECTION/FIGURE/ENTRY
CORRECTION
Table 2.2, "Pin Types"
Added table and the following application note
above the table: “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 3.1, "Absolute
Maximum Ratings"
Updated voltage limits for 5V tolerant pins with
pull-up resistors.
Added the following note below table: “For the 5V
tolerant pins that have a pull-up resistor, the pullup voltage must not exceed 3.6V when the device
is unpowered.”
Table 3.2, "Electrical
Specifications"
SMSC EMC2101
Updated supply current max TBD to 400. Updated
Standby current from 180 to 270. Added conditions
to the leakage current.
57
DATASHEET
Revision 2.54 (06-16-09)