EMC1001 DATA SHEET (01/30/2007) DOWNLOAD

EMC1001
1.5°C SMBus
Temperature Sensor in
Miniature SOT-23
PRODUCT FEATURES
Datasheet
General Description
Features
„
The EMC1001 is a tiny SMBus temperature sensor with
±1.5°C accuracy and two interrupts. Packaged in a
SOT23-6, the EMC1001 provides an accurate, low-cost,
low-current, solution for critical temperature monitoring
in a PC or embedded applications.
Self Contained Internal Temperature Sensor
— 0.25°C resolution
— ±1.5°C Accuracy 40°C to 85°C
„
„
Small 6-lead SOT lead-free RoHS compliant
packages
SMBus address selected by external resistor
— Select 1 of 4 per package, 8 addresses available
The EMC1001 generates two separate interrupts with
programmable thermal trip points. The THERM output
operates as a thermostat with programmable threshold
and hysteresis. The ALERT output can be configured
as a maskable SMBus alert with programmable
window comparator limits, or as a second THERM
output. An efficient fan control system can be created
since this output may be used to control a fan.
„
„
„
Maskable Interrupt using ALERT
One-shot Command during standby
Low Power, 3.0V to 3.6V Supply
— 47uA at 0.0625 Conversions per Second (Typical)
— 4.8uA in Standby (Typical)
„
„
SMBus 2.0 Compliant interface
Programmable temperature conversion rate
A power down mode extends battery life in portable
applications.
Applications
„
Each part number may be configured to respond to one
of four separate SMBus addresses.
„
„
„
„
Desktop and Notebook Computers
Thermostats
Smart batteries
Industrial/Automotive
Other Electronic Systems
Simplified Block Diagram
EMC1001
Address Pointer Register
Switching
Current
Low Limit Registers
THERM Limit Register
THERM Hysteresis Register
Configuration Register
Status Register
Interrupt Masking
SMBus Interface
Temperature
Register
High Limit Registers
Digital Mux
10-bit
delta-sigma
ADC
Limit Comparator
Internal
Temp Diode
Conversion Rate Register
SMCLK
SMDATA
ALERT
THERM
SMSC EMC1001
DATASHEET
Revision 1.6 (01-29-07)
1.5°C SMBus Temperature Sensor in Miniature SOT-23
Datasheet
Order Number(s):
EMC1001-AFZQ-TR for 6 pin, SOT 23 Lead-Free RoHS compliant package
(tape and reel)
EMC1001-1-AFZQ-TR for 6 pin, SOT 23 Lead-Free RoHS compliant package
(alternate addresses, tape and reel)
See Table 1.2, "SMBus Address Configuration Information," on page 3
Reel size is 8,000 pieces.
80 ARKAY DRIVE, HAUPPAUGE, NY 11788 (631) 435-6000, FAX (631) 273-3123
Copyright © 2007 SMSC or its subsidiaries. All rights reserved.
Circuit diagrams and other information relating to SMSC products are included as a means of illustrating typical applications. Consequently, complete information sufficient for
construction purposes is not necessarily given. Although the information has been checked and is believed to be accurate, no responsibility is assumed for inaccuracies. SMSC
reserves the right to make changes to specifications and product descriptions at any time without notice. Contact your local SMSC sales office to obtain the latest specifications
before placing your product order. The provision of this information does not convey to the purchaser of the described semiconductor devices any licenses under any patent
rights or other intellectual property rights of SMSC or others. All sales are expressly conditional on your agreement to the terms and conditions of the most recently dated
version of SMSC's standard Terms of Sale Agreement dated before the date of your order (the "Terms of Sale Agreement"). The product may contain design defects or errors
known as anomalies which may cause the product's functions to deviate from published specifications. Anomaly sheets are available upon request. SMSC products are not
designed, intended, authorized or warranted for use in any life support or other application where product failure could cause or contribute to personal injury or severe property
damage. Any and all such uses without prior written approval of an Officer of SMSC and further testing and/or modification will be fully at the risk of the customer. Copies of
this document or other SMSC literature, as well as the Terms of Sale Agreement, may be obtained by visiting SMSC’s website at http://www.smsc.com. SMSC is a registered
trademark of Standard Microsystems Corporation (“SMSC”). Product names and company names are the trademarks of their respective holders.
SMSC DISCLAIMS AND EXCLUDES ANY AND ALL WARRANTIES, INCLUDING WITHOUT LIMITATION ANY AND ALL IMPLIED WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE, TITLE, AND AGAINST INFRINGEMENT AND THE LIKE, AND ANY AND ALL WARRANTIES ARISING FROM ANY COURSE
OF DEALING OR USAGE OF TRADE. IN NO EVENT SHALL SMSC BE LIABLE FOR ANY DIRECT, INCIDENTAL, INDIRECT, SPECIAL, PUNITIVE, OR CONSEQUENTIAL
DAMAGES; OR FOR LOST DATA, PROFITS, SAVINGS OR REVENUES OF ANY KIND; REGARDLESS OF THE FORM OF ACTION, WHETHER BASED ON CONTRACT;
TORT; NEGLIGENCE OF SMSC OR OTHERS; STRICT LIABILITY; BREACH OF WARRANTY; OR OTHERWISE; WHETHER OR NOT ANY REMEDY OF BUYER IS HELD
TO HAVE FAILED OF ITS ESSENTIAL PURPOSE, AND WHETHER OR NOT SMSC HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
Revision 1.6 (01-29-07)
2
DATASHEET
SMSC EMC1001
1.5°C SMBus Temperature Sensor in Miniature SOT-23
Datasheet
Chapter 1 Pin Configuration
ADDR/THERM
1
6
SMDATA
GND
2
5
ALERT/THERM2
VDD
3
4
SMCLK
Figure 1.1 EMC1001 Pin Configuration
Table 1.1 Pin Description
PIN
PIN NO.
DESCRIPTION
ADDR/THERM
1
Logic output that can be used to turn on/off a fan or throttle a CPU clock
in the event of an over-temperature condition. This is an open-drain
output. This pin is sampled following power up and the value of the pull
up resistor determines the SMBus slave address per Table 1.2.Total
capacitance on this pin must not exceed 100 pF, and the pull-up resistor
must be connected to the same supply voltage as VDD
GND
2
Ground.
VDD
3
Supply Voltage, 3.0V to 3.6V.
SMCLK
4
SMBus clock input.
ALERT/THERM2
5
Logic output used as interrupt, SMBus alert or as a second THERM output.
This is an open-drain output.
SMDATA
6
SMBus data input/output, open drain output.
Table 1.2 SMBus Address Configuration Information
PART NUMBER
EMC1001
EMC1001-1
ADDR/THERM
PULL-UP RESISTOR
SMBUS
ADDRESS
PACKAGE
DESCRIPTION
7.5kΩ ±5% Note 1.1, Note 1.2
1001 000b
6-Lead SOT-23
12kΩ ±5% Note 1.2
1001 001b
6-Lead SOT-23
20kΩ ±5% Note 1.2
0111 000b
6-Lead SOT-23
33kΩ ±5% Note 1.2
0111 001b
6-Lead SOT-23
7.5kΩ ±5% Note 1.1, Note 1.2
1001 010b
6-Lead SOT-23
12kΩ ±5% Note 1.2
1001 011b
6-Lead SOT-23
20kΩ ±5% Note 1.2
0111 010b
6-Lead SOT-23
33kΩ ±5% Note 1.2
0111 011b
6-Lead SOT-23
Note 1.1
This value must be greater than 1kΩ ±5% and less than or equal to 7.5kΩ ±5%.
Note 1.2
The pull-up resistor must be connected to VDD (pin 1), and the total capacitance on this
pin must be less than 100pF.
SMSC EMC1001
3
DATASHEET
Revision 1.6 (01-29-07)
1.5°C SMBus Temperature Sensor in Miniature SOT-23
Datasheet
Table 1.3 Absolute Maximum Ratings
PARAMETER
RATING
UNIT
Supply Voltage VDD
-0.3 to 5.0
V
Voltage on ALERT/THERM2, SMDATA and SMCLK pins
-0.3 to 5.5
V
Voltage on any other pin
-0.3 to VDD+0.3
V
Operating Temperature Range
-25 to +125
°C
Storage Temperature Range
-55 to +150
°C
Lead Temperature Range
Refer to JEDEC
Spec. J-STD-020
Package Thermal Characteristics for SOT23-6
Power Dissipation
TBD
mW @ 70oC
Thermal Resistance
111.5
oC/W
2000
V
ESD Rating, All Pins (Human Body Model)
Note: Stresses above those listed could cause 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.
Revision 1.6 (01-29-07)
4
DATASHEET
SMSC EMC1001
1.5°C SMBus Temperature Sensor in Miniature SOT-23
Datasheet
Chapter 2 Electrical Characteristics
Table 2.1 Electrical Characteristics
VDD=3.0V to 3.6V, TA= -25°C to +125°C, Typical values at TA = 27°C unless otherwise noted
PARAMETER
SYMBOL
MIN
TYP
MAX
UNITS
3.3
3.6
V
CONDITIONS
DC Power
Supply Voltage
VDD
Average Operating Current
IDD
47
TBD
μA
0.0625 conversion/s
See Table 4.6,
"Conversion Rates,"
on page 14
IPD
4.8
10
μA
Standby mode
±0.5
±1.5
°C
40°C≤TA≤85°C
±1
±3
°C
-25°C≤TA≤125°C
3.0
Temperature Measurement
Accuracy
Resolution
0.25
°C
Conversion Time
26
ms
Voltage Tolerance
Voltage at pin (ADDR/THERM, )
VTOL
-0.3
3.6
V
Voltage at pin (ALERT/THERM2,
SMDATA,SMCLK)
VTOL
-0.3
5.5
V
Digital Outputs (ADDR/THERM, ALERT/THERM2)
Output Low Voltage
VOL
High Level Leakage Current
IOH
0.1
0.4
V
IOUT=-4mA
1
μA
VOUT=VDD
SMBus Interface (SMDATA,SMCLK)
Input High Level
VIH
Input Low Level
VIL
Input High/Low Current
IIH/IIL
2.0
V
-1
0.8
V
1
μA
Hysteresis
500
mV
Input Capacitance
5
pF
Output Low Sink Current
6
mA
SMDATA = 0.6V
SMBus Timing
Clock Frequency
FSMB
10
Spike Suppression
SMSC EMC1001
5
DATASHEET
400
kHz
50
ns
Revision 1.6 (01-29-07)
1.5°C SMBus Temperature Sensor in Miniature SOT-23
Datasheet
Table 2.1 Electrical Characteristics (continued)
VDD=3.0V to 3.6V, TA= -25°C to +125°C, Typical values at TA = 27°C unless otherwise noted
PARAMETER
SYMBOL
MIN
TYP
MAX
UNITS
CONDITIONS
Bus free time Start to Stop
TBUF
1.3
μs
Hold time Start
THD:STA
0.6
μs
Setup time Start
TSU:STA
0.6
μs
Setup time Stop
TSU:STO
0.6
μs
Data Hold Time
THD:DAT
0.3
μs
Data Setup Time
TSU:DAT
100
ns
Clock Low Period
TLOW
1.3
μs
Clock High Period
THIGH
0.6
μs
Clock/Data Fall Time
TF
*
300
ns
*Min = 20+0.1Cb ns
Clock/Data Rise Time
TR
*
300
Note
2.1
ns
*Min = 20+0.1Cb ns
Capacitive Load (each bus line)
Cb
0.6
400
pF
Note 2.1
Revision 1.6 (01-29-07)
300nS rise time max is required for 400kHz bus operation. For lower clock frequencies,
the maximum rise time is (0.1/FSMB)+50nS
6
DATASHEET
SMSC EMC1001
1.5°C SMBus Temperature Sensor in Miniature SOT-23
Datasheet
Chapter 3 System Management Bus Interface Protocol
A host controller, such as an SMSC I/O controller, communicates with the EMC1001 via the two wire
serial interface named SMBus. The SMBus interface is used to read and write registers in the
EMC1001, which is a slave-only device. A detailed timing diagram is shown in Figure 3.1.
T LO W
T H IG H
T H D :STA
TR
T SU :S TO
TF
SM CLK
T H D :S TA
T H D :D A T T S U :D AT
T SU :S TA
SM DA TA
TBUF
S
P
S
S - S tart C ondition
P - Stop Condition
P
Figure 3.1 System Management Bus Timing Diagram
The EMC1001 implements a subset of the SMBus specification and supports Write Byte, Read Byte,
Send Byte, Receive Byte, and Alert Response Address protocols. as shown. In the tables that describe
the protocol, the “gray” columns indicate that the slave is driving the bus.
3.1
Write Byte
The Write Byte protocol is used to write one byte of data to the registers as shown below:
Table 3.1 SMBus Write Byte Protocol
START
SLAVE ADDRESS
WR
ACK
COMMAND
ACK
DATA
ACK
STOP
1
7
1
1
8
1
8
1
1
3.2
Read Byte
The Read Byte protocol is used to read one byte of data from the registers as shown below:
Table 3.2 SMBus Read Byte Protocol
START
SLAVE ADDRESS
WR
ACK
COMMAND
ACK
START
SLAVE ADDRESS
RD
ACK
DATA
NACK
STOP
1
7
1
1
8
1
1
7
1
1
8
1
1
3.3
Send Byte
The Send Byte protocol is used to set the Internal Address Register to the correct Address. The Send
Byte can be followed by the Receive Byte protocol described below in order to read data from the
register. The send byte protocol cannot be used to write data - if data is to be written to a register then
the write byte protocol must be used as described in subsection above. The send byte protocol is shown
in Table 3.3.
Table 3.3 SMBus Send Byte Protocol
FIELD:
START
SLAVE ADDR
WR
ACK
REG. ADDR
ACK
STOP
Bits:
1
7
1
1
8
1
1
SMSC EMC1001
7
DATASHEET
Revision 1.6 (01-29-07)
1.5°C SMBus Temperature Sensor in Miniature SOT-23
Datasheet
3.4
Receive Byte
The Receive Byte protocol is used to read data from a register when the internal register address pointer
is known to be at the right location (e.g. set via Send Byte). This can be used for consecutive reads of
the same register as shown below:
Table 3.4 SMBus Receive Byte Protocol
FIELD:
START
SLAVE ADDR
RD
ACK
REG. DATA
NACK
STOP
Bits:
1
7
1
1
8
1
1
3.5
Alert Response Address
The ALERT/THERM2 output can be used as an SMBALERT# as described in 4.3, "ALERT/THERM2
Output," on page 11. The Alert Response Address is polled by the Host whenever it detects an
SMBALERT#, i.e. when the ALERT/THERM2 pin is asserted. The EMC1001 will acknowlege the Alert
Response Address and respond with its device address as shown below.
Table 3.5 Modified SMBus Receive Byte Protocol Response to ARA
FIELD:
START
ALERT
RESPONSE
ADDRESS
Bits:
1
7
3.6
RD
ACK
EMC1001 SLAVE
ADDRESS
NACK
STOP
1
1
8
1
1
SMBus Addresses
The EMC1001 is available in two versions, each of which has four 7-bit slave addresses that are
enabled based on the pull-up resistor on the ADDR/THERM pin. The value of this pull up resistor
determines the slave address per Table 1.2 on page 3. Attempting to communicate with the EMC1001
SMBus interface with an invalid slave address or invalid protocol results in no response from the device
and does not affect its register contents. The EMC1001 supports stretching of the SMCLK signal by
other devices on the SMBus but will not perform this operation itself. The EMC1001 has an SMBus
timeout feature. Bit 7 of the SMBus Timeout Enable register enables this function when set to 1 (the
default setting is 0). When this feature is enabled, the SMBus will timeout after approximately 25ms
of inactivity.
Revision 1.6 (01-29-07)
8
DATASHEET
SMSC EMC1001
1.5°C SMBus Temperature Sensor in Miniature SOT-23
Datasheet
Chapter 4 Product Description
The EMC1001 is an SMBus temperature that monitors a single temperature zone. Thermal
management is performed in cooperation with a host device. The host reads the temperature data from
the EMC1001 and takes appropriate action such as controlling fan speed or processor clock frequency.
The EMC1001 has programmable temperature limit registers that define a safe operating window. After
the host has configured the temperature limits, the EMC1001 can operate as a free-running
independent watchdog to warn the host of temperature hot spots without requiring the host to poll the
device. The ADDR/THERM output can be used to control a fan without host intervention.
EMC1001
Host
SMCLK
SMDATA
Internal
Diode
SMBus
Interface
ALERT/THERM2
ADDR/THERM
Fan
Driver
Figure 4.1 Controlling a fan without host intervention.
The EMC1001 has two basic modes of operation:
4.1
„
Run Mode: In this mode, the EMC1001 continuously converts temperature data and updates its
registers. The rate of temperature conversion is configured as shown in Section 4.9 on page 14.
„
Standby Mode: In this mode, the EMC1001 is placed in standby to conserve power as described
in Section 4.5 on page 12.
Temperature Monitors
Thermal diode temperature measurements are based on the change in forward bias voltage (ΔVBE) of
a diode when operated at two different currents:
where:
ΔVBE = VBE _ HIGH − VBE _ LOW
⎛I
ln⎜⎜ HIGH
=
q
⎝ I LOW
ηkT
⎞
⎟⎟
⎠
k = Boltzmann’s constant
T = absolute temperature in Kelvin
q = electron charge
η = diode ideality factor
The change in
SMSC EMC1001
ΔVBE voltage is proportional to absolute temperature T.
9
DATASHEET
Revision 1.6 (01-29-07)
1.5°C SMBus Temperature Sensor in Miniature SOT-23
Datasheet
VDD
Ihigh
Internal or
Remote Diode
Ilow
Ibias
Delta Vbe
Sample
&
Hold
Bias
Diode
1-bit
delta-sigma
Modulator
Digital
Averaging
Filter
10-bit Output
Figure 4.2 Detailed Block Diagram
Figure 4.2 shows a detailed block diagram of the temperature measurement circuit. The EMC1001
incorporates switched capacitor technology that integrates the temperature diode ΔVBE from different
bias currents. The negative terminal, DN, for the temperature diode is internally biased with a forward
diode voltage referenced to ground.
The advantages of this architecture over Nyquist rate FLASH or SAR converters are superb linearity
and inherent noise immunity. The linearity can be directly attributed to the delta-sigma ADC single-bit
comparator while the noise immunity is achieved by the ~20ms integration time which translates to
50Hz input noise bandwidth.
4.2
Temperature Measurement Results and Data
The 10-bit temperature measurement results are stored in temperature value registers. Table 4.1
shows the two’s complement temperature data format with an LSB equivalent to 0.25°C.
Table 4.1 Temperature Data Format
VALID RANGE
–40°C TO 125°C
TEMPERATURE
TWO’S COMPLEMENT
-0.25°C
0.0°C
+0.25°C
+0.50°C
+0.75°C
+1°C
1111 1111 11 Note 4.1
0000 0000 00
0000 0000 01
0000 0000 10
0000 0000 11
0000 0001 00
+125°C
0111 1101 00 Note 4.2
Note 4.1
Temperature measurement returns 1100 0000 00 for all temperatures ≤ -64.00°C
Note 4.2
Temperature measurement returns 0111 1111 11 for all temperatures ≥ +127.75°C
The eight most significant bits are stored in the Temperature Value High Byte register and the two least
significant bits stored in the Temperature Value Low Byte register as outlined in Table 4.2. The six LSB
positions of the Temperature Value Low Byte register always read zero. In Table 4.2, the upper case
Revision 1.6 (01-29-07)
10
DATASHEET
SMSC EMC1001
1.5°C SMBus Temperature Sensor in Miniature SOT-23
Datasheet
“B” shows the bit position of a 16-bit word created by concatenating the High Byte and Low Byte, and
the lower case “b” shows the bit position in the 10-bit value.
Table 4.2 Bit Position of Two Byte Values
HIGH BYTE
B15
b9
4.3
B14
b8
B13
b7
B12
b6
B11
b5
LOW BYTE
B10
b4
B9
b3
B8
b2
B7
b1
B6
b0
B5
0
B4
0
B3
0
B2
0
B1
0
B0
0
ALERT/THERM2 Output
The ALERT/THERM2 output asserts if an out of limit measurement is detected (TA ≤ low limit or TA >
high limit). The ALERT/THERM2 pin is an open drain output and requires a pull up resistor to VDD.The
ALERT/THERM2 pin can be used as an SMBALERT#, or may be configured as a second THERM output.
As described in the SMBus specification, an SMBus slave may inform the SMBus master that it wants
to talk by asserting the SMBALERT# signal. One or more ALERT outputs can be hardwired together
as a wired-or bus to a common input.
The ALERT/THERM2 pin resets when the EMC1001 responds to an alert response address (ARA=0001
100) sent by the host, and if the out of limit condition no longer exists, but it does not reset if the error
condition remains. The ALERT/THERM2 pin can be masked so that it will not assert in the event of an
out of limit temperature measurement, except when it is configured as a second THERM pin.
Logic
Level
Temp
Temperature High Limit
SMBus ARA
Temperature Low Limit
Logic High
ALERT/THERM2
Time
Figure 4.3 ALERT Response to Temperature Limits Exceeded
The ALERT/THERM2 pin can be configured as a second THERM pin that asserts when the temperature
measurement exceeds the Temperature High Limit value. In this mode, the output will not de-assert
until the temerature drops below the Temperature High Limit minus the THERM Hysteresis value.
4.4
ADDR/THERM Output
The ADDR/THERM output asserts if the temperature measurement exceeds the programmable THERM
limit. It can be used to drive a fan or other failsafe devices. The ADDR/THERM pin is open drain and
requires a pull up resistor to VDD. The value of this pull up resistor determines the slave address per
Table 1.2 on page 3. The ADDR/THERM pin cannot be masked.
When the ADDR/THERM pin is asserted, it will not de-assert until the temperature drops below the
THERM limit minus the THERM hysteresis value.
SMSC EMC1001
11
DATASHEET
Revision 1.6 (01-29-07)
1.5°C SMBus Temperature Sensor in Miniature SOT-23
Datasheet
Temp
THERM
Hysteresis
THERM Limit
Logic
Level
THERM Limit - THERM Hysterisis
Logic High
THERM
Time
Figure 4.4 THERM Response to THERM Limit Exceeded
4.5
Standby Mode
The EMC1001 can be set to standby mode (low power) by setting a bit in the Configuration Register
as described in Section 4.8 on page 13. This shuts down all internal analog functions while the SMBus
remains enabled. When the EMC1001 is in standby mode, a One-Shot command measurement can
be initiated. The user may also write new values to the limit registers described in Section 4.10 on
page 15 while in standby. If the previously stored temperature is outside any of the new limits, the
ALERT/THERM2 output will respond as described in Section 4.3 and the ADDR/THERM output will
respond as described in Section 4.4.
4.6
Register Allocation
The following registers shown in Table 4.3 are accessible through the SMBus:
Table 4.3 Register Map
REGISTER
ADDRESS
(HEX)
R/W
REGISTER NAME
00
01
02
03
04
05
06
07
08
0F
20
21
22
FD
R
R
R
R/W
R/W
R/W
R/W
R/W
R/W
W
R/W
R/W
R/W
R
Temperature Value High Byte
Status
Temperature Value Low Byte
Configuration
Conversion Rate
Temperature High Limit High Byte
Temperature High Limit Low Byte
Temperature Low Limit High Byte
Temperature Low Limit Low Byte
One-Shot
THERM Limit
THERM Hysteresis
SMBus Timeout Enable
Product ID Register
FE
FF
R
R
Manufacture ID
Revision Number
Revision 1.6 (01-29-07)
12
DATASHEET
POWER-ON DEFAULT
0000 0000
undefined
0000 0000
0000 0000
0000 0100
0101 0101 (85°C)
0000 0000
0000 0000 (0°C)
0000 0000
N/A
0101 0101 (85°C)
0000 1010 (10°C)
0000 0001
0000 0000 (EMC1001)
0000 0001 (EMC1001-1)
0101 1101
0000 0011 Note 4.3
SMSC EMC1001
1.5°C SMBus Temperature Sensor in Miniature SOT-23
Datasheet
Note 4.3
Revision number may change. Please obtain the latest version of this document from the
SMSC web site.
At device power-up, the default values are stored in all registers. A power-on-reset is initiated when
power is first applied to the part and the VDD supply exceeds the POR threshold. Reads of undefined
registers will return 00h and writes to undefined registers will be ignored.
The EMC1001 uses an interlock mechanism that locks the low byte value when the high byte register
is read. This prevents updates to the low byte register between high byte and low byte reads. This
interlock mechanism requires that the high byte register always be read prior to reading the low byte
register.
4.7
Status Register
The status register is a read only register that stores the operational status of the part. When either
TLOW or THIGH are set (TA ≤ low limit or TA > high limit) and the ALERT/THERM2 pin is not masked,
the ALERT/THERM2 pin will assert. See Section 4.3 on page 11 for more details on the ALERT
function.
Table 4.4 Status Register
STATUS REGISTER
BIT
NAME
FUNCTION
7
Busy
1 when ADC is converting
6
THIGH
1 when Temperature High Limit is exceeded
5
TLOW
1 when Temperature Low Limit is exceeded
4
Reserved
3
Reserved
2
Reserved
1
Reserved
0
THRM
1 when THERM limit is exceeded
Bit 7 indicates that the ADC is busy converting a value. Bits 6 and 5 indicate that the temperature
measurement is above or below the limits respectively. Bit 0 indicates that the measured temperature
has exceeded the THERM limit. When bit 0 goes high the ADDR/THERM output will be asserted.
Each bit is cleared individually when the status register is read, provided that the error condition for
that bit no longer exists. The ALERT/THERM2 output is latched and will not be reset until the host has
responded with an alert response address (ARA=0001 100). The ALERT/THERM2 output will not reset
if the status register has not been cleared.
4.8
Configuration Register
The configuration register controls the functionality of the temperature measurements.
SMSC EMC1001
13
DATASHEET
Revision 1.6 (01-29-07)
1.5°C SMBus Temperature Sensor in Miniature SOT-23
Datasheet
Table 4.5 Configuration Register
CONFIGURATION REGISTER
BIT
NAME
FUNCTION
DEFAULT
7
MASK1
0 = ALERT enabled
1 = ALERT disabled
0
6
RUN/STOP
0 = Active mode (continuously running)
1 = Standby mode
0
5
ALERT or THERM2
0 = ALERT
1 = THERM2
0
4–0
Reserved
0
Bit 7 is used to mask the ALERT/THERM2 signal. When this bit is set to 0, any out of limit condition
will assert ALERT/THERM2. This bit is ignored if the ALERT/THERM2 pin is configured as THERM2 signal
by bit 5.
Bit 6 initiates ADC conversions. When this bit is low, the ADC will convert temperatures in a
continuous mode. When this bit is high, the ADC will be in standby mode, thus reducing supply
current significantly though the SMBus will still be active. If bit 6 is 1 and the one-shot register is
written to, the ADC will execute a temperature measurement and then return to standby mode.
Bit 5 sets the ALERT/THERM2 pin to act as either an SMBALERT# signal or as the THERM2 signal. If
bit 5 is set to 1 the ALERT/THERM2 pin acts as the THERM2 signal and bit 7 is ignored.
4.9
Conversion Rate Register
The conversion rate register determines how many times the temperature value will be updated per
second. The lowest 4 bits configure a programmable delay that waits between consecutive conversion
cycles to obtain the desired conversion rate. Table 4.6 shows the conversion rate and the associated
quiescent current.
Table 4.6 Conversion Rates
CONVERSION RATE
VALUE
CONVERSIONS/SECOND
TYPICAL QUIESCENT CURRENT (μA)
00h
01h
02h
03h
04h
05h
06h
07h
08h
09h
0Ah to FFh
0.0625
0.125
0.25
0.5
1
2
4
8
16
32
Reserved
36
37
38
40
44
54
71
109
182
326
Revision 1.6 (01-29-07)
14
DATASHEET
SMSC EMC1001
1.5°C SMBus Temperature Sensor in Miniature SOT-23
Datasheet
4.10
Limit Registers
The user can configure high and low temperature limits and an independent THERM limit. The
temperature high limit (TH) is a 10-bit value that is set by the Temperature High Limit High Byte register
and the Temperature High Limit Low Byte register. The Temperature High Limit Low Byte register
contains the two least significant bits as shown in Table 4.2 on page 11. The two least significant bits
are stored in the upper two bits of the register, and the six LSB positions of this register always read
zero.
The temperature low limit (TL) is a 10-bit value that is set by the Temperature Low Limit High Byte
register and the Temperature Low Limit Low Byte register as shown in Table 4.2 on page 11.
The limits are compared to the temperature measurement results (TINT) and have been exceeded if
(TINT ≤ TL or TINT > TH). If either limit is exceeded then the appropriate bit is set high in the status
register and the ALERT/THERM2 output will respond as described in Section 4.3 on page 11.
The THERM limit (TTH) is a single byte value set by the THERM Limit register. Exceeding the THERM
limit asserts the ADDR / THERM signal as described in Section 4.4 on page 11. When the
ALERT/THERM2 pin is configured as THERM2, then exceeding the high limit asserts this pin.
4.11
THERM Hysteresis Register
The THERM hysteresis register holds a hysteresis value that determines the de-assertion of THERM
as shown in Figure 4.4 on page 12. It defaults to 10°C and can be set by the user at any time after
power up. When the ALERT/THERM2 pin is configured as THERM2, then the hysteresis value also
impacts the de-assertion of THERM2.
4.12
One-Shot Register
Writing to the one-shot register while in standby mode initiates a conversion and comparison cycle.
The EMC1001 will execute a temperature measurement, compare the data to the limit registers and
return to the standby mode. A write to the one-shot register will be ignored if it occurs while the
EMC1001 is in run mode.
4.13
SMBus Timeout Enable
The EMC1001 has an SMBus timeout feature. Bit 7 of the SMBus Timeout Enable register enables
this function when set to 1 (the default setting is 0). When this feature is enabled, the SMBus will
timeout after approximately 25ms of inactivity.
SMSC EMC1001
15
DATASHEET
Revision 1.6 (01-29-07)
REVISION HISTORY
D
REVISION
3
DES CRIPTION
A
INITIAL RELEASE
DATE
RELEAS ED BY
7/07/04
S .K.ILIEV
SEE DETAIL "A"
6
N
3
4
E
E1
1
2
INDEX AREA
(D/2 x E1/2)
3
e
5X b
2
4
c
4
5
END VIEW
TOP VIEW
16
DATASHEET
H
C
A2
GAUGE PLANE
A
0.25
NOTES:
1. "N" IS THE TOTAL NUMBER OF LEADS .
2. TRUE POSITION SPREAD TOLERANCE IS ± 0.10mm 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 0.25 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 0.08 TO
0.15 mm FROM THE LEAD TIP.
5. DETAILS OF PIN 1 IDENTIFIER ARE OPTIONAL, BUT MUST BE LOCATED WITHIN THE
INDEX AREA INDICATED (SEE TOP VIEW).
6. FIVE LEAD PACKAGE IS A VERSION OF 6 LEAD PACKAGE, WHERE LEAD #5 HAS BEEN
REMOVED FROM 6 LEAD PACKAGE.
SEATING PLANE
A1
L
ccc C
0
L1
SIDE VIEW
DETAIL "A" (SCALE: 2/1)
UNLESS OTHERWISE SPECIFIED
DIMENSIONS ARE IN MILLIME TERS
AND TOLERANCES ARE:
DECIMAL
±0.1
X.X
X.XX ±0.05
X.XXX ±0.025
THIRD ANGLE PROJECTION
80 ARKAY DRIVE
HAUP PAUGE, NY 11788
USA
ANGULAR
±1°
TITLE
NAME
DATE
S.K.ILIEV
7/06/04
DIM AND TOL PER ASME Y14.5M - 1994
MATERIAL
N = 5 LEADS
N = 6 LEADS
FINISH
3-D VIEWS
-
S.K.ILIEV
SMSC EMC1001
S.K.ILIEV
REV
DWG NUMBER
CHECKED
MO-5/6 SOT-2.9x1.6
7/06/04
APPROVED
PRINT WITH "SCALE TO FIT"
DO NOT SCALE DRAWING
PACKAGE OUTLINE: 5/6 PIN SOT
1.6mm BODY WIDTH, 0.95mm PITCH
DRAWN
SCALE
7/07/04
STD COMPLIANCE
1:1
JEDEC: MO-178 / AA, AB
Figure 5.1 EMC1001, 6 Pin SOT Package Outline; 1.6mm Body Width, 0.95mm Pitch
A
SHEET
1 OF 1
1.5°C SMBus Temperature Sensor in Miniature SOT-23
Datasheet
Revision 1.6 (01-29-07)
Chapter 5 Package Outline
Similar pages