MICROCHIP TCM1617

EVALUATION
KIT
AVAILABLE
TCM1617
SMBus Thermal Sensor with External Diode Input
FEATURES
GENERAL DESCRIPTION
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The TCM1617 is a serially programmable temperature
sensor optimized for monitoring modern high performance
CPUs with on-board integrated thermal diodes. Temperature data is converted from the CPU’s thermal diode outputs
and made available as an 8-Bit digital word.
Communication with the TCM1617 is accomplished via
the standard System Management Bus (SMBus) commonly
used in modern computer systems. This permits reading the
current internal/external temperature, programming the
threshold setpoints, and configuring the device. Additionally, an interrupt is generated on the ALERT# pin when
temperature moves outside the preset threshold windows in
either direction.
A Standby command may be sent via the SMBus by
signaling the STBY# input to activate the low-power Standby
mode. Registers can be accessed while in Standby mode.
Address selection inputs allow up to nine TCM1617s to
share the same 2-wire SMBus for multi-zone monitoring.
All registers can be read by the host, and both polled and
interrupt driven systems are easily accommodated. Small
size, low installed cost, and ease of use make the TCM1617
an ideal choice for implementing sophisticated system management schemes, such as ACPI.
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Includes Internal External Sensing Capability
Outputs Temperature as 8-Bit Digital Word
Solid State Temperature Sensing; 1°C Resolution
3.0 – 5.5V Operating Range
Independent Internal and External Threshold
Set-Points With ALERT# Interrupt Output
SMBus 2-Wire Serial Interface
Up To Nine TCM1617s May Share the Same Bus
Standby Mode for Low Standby Power
Low Power ............................ 70µA (max) Operating
...................................... 10µA (max) Standby Mode
16-Pin Plastic QSOP Package
TYPICAL APPLICATIONS
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Thermal Protection For Intel “Deschutes”
Pentium II™ and Other High Performance CPUs
with Integrated On-Board Diode — No Sensor
Mounting Problems!
Accurate Thermal Sensing From Any Si Junction
Diode
Thermal Management in Electronic Systems:
Computers, Network Equipment, Power Supplies
ORDERING INFORMATION
BLOCK DIAGRAM
Internal
Sensor
(Diode)
D+
D–
∆∑
Modulator
Control
Logic
Part No.
Package
Temp. Range
TCM1617MQR
TCM1617EV
QSOP-16
–55°C to +125°C
Evaluation Kit for TCM1617
PIN CONFIGURATION
ALERT#
STBY#
NC
1
16 NC
Int. Temp
VDD
2
15 STBY#
Ext. Temp
D+
3
14
SCL
D–
4
13
NC
NC
5
12
SDA
ADD 1
6
11
ALERT#
GND
7
10
ADD0
GND
8
9
NC
Register Set
Status Byte
SCL
Config. Byte
SDA
Conv. Rate
Ext. Hi Limit
Ext. Lo Limit
SMBus
Interface
Int. Hi Limit
ADD 0
Int. Lo Limit
ADD 1
TCM1617
16-Pin Plastic QSOP
 2001 Microchip Technology Inc.
DS21485A
1
TCM1617-1 2/5/99
SMBus Thermal Sensor with External Diode Input
TCM1617
*Static-sensitive device. Unused devices must be stored in conductive
material. Protect devices from static discharge and static fields. Stresses
above those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only and functional
operation of the device at these or any other conditions above those
indicated in the operational sections of the specifications is not implied.
Exposure to Absolute Maximum Rating Conditions for extended periods
may affect device reliability.
ABSOLUTE MAXIMUM RATINGS*
Power Supply Voltage (VDD) .........................................6V
Voltage On Any Pin ............ (GND – 0.3V) to (VDD + 0.3V)
Operating Temperature (TA) .................. –55°C to +125°C
Storage Temperature (TSTG) .................. –65°C to +150°C
SMBus Input/Output Current ................. –1 mA to +50 mA
D– Input Current ......................................................±1 mA
Max. Power Dissipation ........................................330 mW
ELECTRICAL CHARACTERISTICS: VDD = 3.3V, –55°C ≤ TA ≤ 125°C, unless otherwise noted.
Symbol
Parameter
Test Conditions
Min
Typ
Max
Unit
–55 ≤ TA ≤ +125°C
3.0
2.4
—
2.80
5.5
2.95
V
V
VDD Falling Edge
0.25 Conv./Sec Rate
SMBus Inactive (Note 1)
2 Conv./Sec Rate
SMBus Inactive (Note 1)
VDD = 3.3V SMBus Active
VDD = 3.3V, SMBus Inactive
Power-Up Only
1.0
—
1.7
—
2.3
70
V
µA
—
—
180
µA
—
—
—
—
—
160
100
10
—
µA
µA
µA
IOL = 1.0 mA (Note 3)
—
—
0.4
V
Power Supply
VDD
VUV-LOCK
VPOR
IDD
Power Supply Voltage
VDD Undervoltage
Lockout Threshold
Power-On Reset Threshold
Operating Current
IDD
Operating Current
IDD-STANDBY Standby Supply Current
IDD-STANDBY Standby Supply Current
IADD-BIAS
ADD[1:0] Bias Current
ALERT# Output
VOL
Output Low Voltage
ADD[1:0] Inputs
VIL
Logic Input Low
—
—
VDD x 0.3
V
VIH
Logic Input High
VDD x 0.7
—
—
V
Logic Input Low
Logic Input High
—
VDD x 0.7
—
—
VDD x 0.3
—
V
V
—
1
—
°C
STBY# Input
VIL
VIH
Temp-to-Bits Converter
TRES
Basic Temperature Resolution
TIERR1
Internal Diode Temperature
+60°C ≤ TA ≤ +100°C
0°C ≤ TA ≤ +125°C
–55°C ≤ TA < 0°C
–2
–3
—
—
—
±3
+2
+3
—
°C
°C
TEERR
External Diode Temperature
(Note 4)
+60°C ≤ TA ≤ +100°C
0°C ≤ TA ≤ +125°C –3
–55°C ≤ TA < 0°C
–3
–5
—
—
±5
+3
+5
—
°C
°C
°C
IDIODE-HIGH
External Diode
High Source Current
(D+) – (D–) ~ 0.65V
—
100
—
µA
IDIODE-LOW
External Diode
Low Source Current
(D+) – (D–) ~ 0.65V
—
10
—
µA
VD-SOURCE
D– Source Voltage
—
0.7
—
V
TCM1617-1
2/5/99
2
 2001 Microchip Technology Inc.
DS21485A
SMBus Thermal Sensor with External Diode Input
TCM1617
ELECTRICAL CHARACTERISTICS (CONT): VDD = 3.3V, –55°C ≤ TA ≤ 125°C, unless otherwise noted.
Symbol
Parameter
Conditions
Min
Typ
Max
Unit
tCONV
Conversion Time
from CHIP STOP to Conv.
Complete (Note 2)
54
83
112
msec
∆CR
Conversion Rate Accuracy
See Conversion Rate Register Desc.
–35
—
+35
%
2-Wire SMBus Interface
VIH
Logic Input High
2.2
—
—
V
VIL
Logic Input Low
—
—
0.8
V
VOL
SDA Output Low
—
—
—
—
0.4
0.6
V
V
CIN
Input Capacitance SDA, SCL
—
5
—
pF
ILEAK
I/O Leakage
–1
0.1
1
µA
IOL = 2 mA (Note 3)
IOL = 4 mA (Note 3)
SMBus PORT AC TIMING: VDD = 3.3V, –55 ≤ (TA = TJ) ≤ 125°C; CL = 80 pF, unless otherwise noted.
Symbol
Parameter
fSMB
tLOW
tHIGH
tR
tF
tSU(START)
SMBus Clock Frequency
Low Clock Period
High Clock Period
SMBus Rise Time
SMBus Fall Time
Start Condition Setup Time
(for Repeated Start Condition)
Start Condition Hold Time
Data in Set Up Time
Data in Hold Time
Stop Condition Setup Time
Bus Free Time Prior to
New Transition
tH(START)
tSU-DATA
tH-DATA
tSU(STOP)
tIDLE
Test Conditions
Min
Typ
Max
Unit
10% to 10%
90% to 90%
10% to 90%
90% to 10%
90% SCL to 10% SDA
10
4.7
4
—
—
4
—
—
—
—
—
—
100
—
—
1,000
300
—
KHz
µsec
µsec
nsec
nsec
µsec
4
1000
1250
4
4.7
—
—
—
—
—
—
—
—
—
—
µsec
nsec
nsec
µsec
µsec
NOTES: 1. Operating current is an average value (including external diode injection pulse current) integrated over multiple conversion cycles.
Transient current may exceed this specification.
2. For true reccurring conversion time see Conversion Rate register description.
3. Output current should be minimized for best temperature accuracy. Power dissipation within the TCM1617 will cause self-heating and
temperature drift error.
4. Refer to Application Note 64.
 2001 Microchip Technology Inc.
DS21485A
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TCM1617-1 2/5/99
SMBus Thermal Sensor with External Diode Input
TCM1617
SMBUS THERMAL S
SMBUS Write Timing Diagram
B
A
ILOW
C
D
E
F
G
H
I
J
K
M
L
IHIGH
SCL
SDA
tSU(START) tH(START)
tH-DATA
tSU-DATA
tSU(STOP)
A = Start Condition
F = Acknowledge Bit Clocked into Master
J = Acknowledge Clocked into Master
B = MSB of Address Clocked into Slave
G = MSB of Data Clocked into Slave
K = Acknowledge Clock Pulse
C = LSB of Address Clocked into Slave
H = LSB of Data Clocked into Slave
L = Stop Condition, Data Executed by Slave
D = R/W Bit Clocked into Slave
I = Slave Pulls SDA Line Low
M = New Start Condition
tIDLE
E = Slave Pulls SDA Line Low
SMBUS Read Timing Diagram
B
A
ILOW
C
D
E
F
G
H
I
K
J
IHIGH
SCL
SDA
tSU(START)
TCM1617-1
2/5/99
tH(START)
tSU(STOP)
tSU-DATA
A = Start Condition
E = Slave Pulls SDA Line Low
I = Acknowledge Clock Pulse
B = MSB of Address Clocked into Slave
F = Acknowledge Bit Clocked into Master
J = Stop Condition
C = LSB of Address Clocked into Slave
G = MSB of Data Clocked into Master
K = New Start Condition
D = R/W Bit Clocked into Slave
H = LSB of Data Clocked into Master
4
tIDLE
 2001 Microchip Technology Inc.
DS21485A
SMBus Thermal Sensor with External Diode Input
TCM1617
PIN DESCRIPTION
Pin Number
Symbol
Type
2
3
4
6,10
7,8
11
12
14
15
1,5, 9, 13,16
VDD
D+
D–
ADD[1:0]
GND
ALERT#
SDA
SCL
STBY#
NC
Power
Bi-Directional
Bi-Directional
Input
Power
Output
Bi-Directional
Input
Input
—
Description
Power Supply Input
Current Source and A/D Positive Input
Current Sink and A/D Negative Input
Address Select Pins (See Address Decode Table)
System Ground
SMBus Interrupt (SMBALERT#)
SMBus Serial Data
SMBus Serial Clock
Standby Enable
Not Connected
PIN DESCRIPTION
SCL
Input. SMBus serial clock. Clocks data into and out of
the TCM1617. See System Management Bus Specification,
rev. 1.0, for timing diagrams.
INT_TEMP equal to or exceeds INT_HLIM
SDA
EXT_TEMP equal to or exceeds EXT_HLIM
INT_TEMP falls below INT_LLIM
Bi-directional. Serial data is transferred on the SMBus
in both directions using this pin. See System Management
Bus Specification, rev. 1.0, for timing diagrams.
EXT_TEMP falls below EXT_LLIM
External Diode “Open”
ADD1, ADD0
The operation of the ALERT# output is controlled by the
MASK1 bit in the CONFIG register. If the MASK1 bit is set to
“1,” no interrupts will be generated on ALERT#. The ALERT#
output is cleared and re-armed by the Alert Response
Address (ARA). This output may be WIRE-ORed with similar outputs from other SMBus devices. If the alarm condition
persists after the ARA, the ALERT# output will be immediately re-asserted.
(NOTE: A pull-up resistor is necessary on ALERT#
since it is an open-drain output. Current sourced from the
pull-up resistor causes power dissipation and may cause
internal heating of the TCM1617. To avoid affecting the
accuracy of internal temperature readings, the pull-up resistors should be made as large as possible.)
Inputs. Sets the 7-bit SMBus address. These pins are
“tri-state,” and the SMBus addresses are specified in the
Address Decode Table below.
(NOTE: The tri-state scheme allows up to nine
TCM1617s on a single bus. A match between the TCM1617’s
address and the address specified in the serial bit stream
must be made to initiate communication. Many SMBuscompatible devices with other addresses may share the
same 2-wire bus (see System Management Bus Specification rev. 1.0 for address allocations). These pins are only
active at power-on reset, and will latch into the appropriate
states.
ALERT#
STBY#
Output, Open Collector, Active Low. The ALERT# output corresponds to the general SMBALERT# signal and
indicates an interrupt event. The TCM1617 will respond to
the standard SMBus Alert Response Address (see SMBus
Specification 1.0) and associated protocol when ALERT# is
asserted. Normally, the ALERT# output will be asserted
when any of the following occurs:
 2001 Microchip Technology Inc.
DS21485A
Input. The activation of Standby mode may be achieved
using either the STBY# pin or the CHIP STOP bit (CONFIG
register). If STBY# is pulled low, the TCM1617 unconditionally enters its low-power Standby mode (IDD = 10 µA, max).
The temperature-to-digital conversion process is halted, but
ALERT remains functional. The TCM1617’s bus interface
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TCM1617-1 2/5/99
SMBus Thermal Sensor with External Diode Input
TCM1617
remains active, and all registers may be read from and
written to normally. The INT_TEMP and EXT_TEMP registers will contain whatever data was valid at the time of
Standby. (Transitions on SDA or SCL due to external bus
activity may increase the Standby power consumption.)
STANDBY MODE
The TC1617 allows the host to put it into a low power
mode (IDD = 10 µA, max) Standby mode. In this mode, the
A/D converter is halted, and the temperature data registers
are frozen. The SMBus port operates normally. Standby
mode can be enabled with either the STBY# input pin or the
CHIP STOP bit in the CONFIG register. The following table
summarizes this operation.
D+
Bi-directional. this pin connects to the anode of the
external diode and is the positive A/D input. Current is
injected into the external diode from the TCM1617, and the
temperature proportional VBE is measured and converted to
digital temperature data.
EXT_TEMP
INT_TEMP
ASSERT
ALERT#
Temperature
Bi-directional. This pin connects to the cathode of the
external diode. Current is sunk from the external diode into
the TCM1617 through this pin. It also is the negative input
terminal to the TCM1617’s A/D converter. This node is kept
at approximately 0.7V above GROUND.
EXT_HLIM
ASSERT
ALERT#
ASSERT
ALERT#
ASSERT
ALERT#
INT_HLIM
EXT_LLIM
Setpoints
D–
INT_LLIM
Time
VDD
ALERT#
Input. Power supply input. See electrical specifications.
Note: This diagram inplies that the appropriate setpoint is moved, temporarily, after each ALERT#
event to suppress re-assertion of ALERT# immediately after the ARA/de-assertion.
GND
Input. Ground return for all TCM1617 functions.
Figure 1. Temperature-vs-Setpoint Event Generation
FUNCTIONAL DESCRIPTION
SMBUS SLAVE ADDRESS
The TCM1617 acquires and converts temperature information from two separate sources, both silicon junction
diodes, with a basic accuracy of ±1°C. One is located on the
TCM1617 die; the other is connected externally. The external diode may be located on another IC die. The analog-todigital converter on the TCM1617 alternately converts temperature data from the two sensors and stores them separately in internal registers.
The system interface is a slave SMBus port with an
ALERT# (SMBALERT#) interrupt output. The interrupt is
triggered when one or more of four preset temperature
thresholds are tripped (see Figure 1). These four thresholds
are user-programmable via the SMBus port. Additionally,
the temperature data can be read at any time through the
SMBus port. Nine SMBus addresses are programmable for
the TCM1617, which allows for a multi-sensor configuration.
Also, there is low-power Standby mode where temperature
acquisition is suspended.
The two pins ADD1 and ADD0 are tri-state input pins
which determine the 7-Bit SMBus slave address of the
TCM1617. The address is latched during POR.
TCM1617-1
2/5/99
SERIAL PORT OPERATION
Standby Mode Operation
STBY#
0
1
1
1
6
Chip Stop Bit
Don’t Care
0
1
1
One Shot?
Don’t Care
Don’t Care
No
Yes
Operating Mode
Standby
Normal
Standby
Normal
(1 Conversion Only,
then Standby)
 2001 Microchip Technology Inc.
DS21485A
SMBus Thermal Sensor with External Diode Input
TCM1617
POR, initialize
all registers
Monitor SMBus
for START
condition
YES
STBY mode
active?
NO
Stop conv., reset
STATUS D[7]
YES
STATUS
read?
Start internal
conversion,
STATUS [D7]
One
shot?
Execute
STATUS read and
clear STATUS
YES
NO
NO
Execute SMBus
read
NO
YES
YES
STBY
active?
STBY
released?
READ
Perform one
conversion cycle
NO
NO
YES
EOC?
NO
NO
NO
Execute SMBus
write
YES
Update
INT_TEMP
Start external
conversion
WRITE
Read/
Write?
Valid
command?
Address
match?
NO
Thermal Trip?
YES
ARA?
YES
YES
STBY
active?
YES
NO
ALERT#
active?
NO
Ext. diode
open?
YES
ARA bus
arbitration
YES
NO
NO
YES
NO
Rest
period over?
Win
arbitration?
YES
EOC?
YES
Disable and re-arm
ALERT#, send
local address to host
NO
Update
EXT_TEMP
YES
One Shot?
NO
NO
Rest Period
according to
CONV_RATE
register
Thermal Trip?
CONFIG
[D7] active?
YES
YES
NO
Reset STATUS
bit D[7]
Set appropriate
STATUS bit
D[6:2]
Enable
ALERT#
Figure 2. TCM1617 Functional Description Flowchart
 2001 Microchip Technology Inc.
DS21485A
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TCM1617-1 2/5/99
SMBus Thermal Sensor with External Diode Input
TCM1617
one or more data bytes. The device address byte includes
a Read/Write selection bit. Each access must be terminated
by a Stop Condition (STOP). A convention called (ACK)
confirms receipt of each byte. Note that SDA can change
only during periods when SCL is LOW (SDA changes while
SCL is High are reserved for Start and Stop conditions.)
The Serial Clock input (SCL) and bi-directional data port
(SDA) form a 2-wire bi-directional serial port for programming and interrogating the TCM1617. The following conventions are used in this bus architecture:
All transfers take place under control of a host, usually
a CPU or microcontroller, acting as the Master, which
Address Decode Table
ADD0
0
0
0
open (3-state)
open (3-state)
open (3-state)
1
1
1
ADD1
0
open (3-state)
1
0
(open (3-state)
1
0
open (3-state)
1
Start Condition (START)
SMBus Address
0011 000
0011 001
0011 010
0101 001
0101 010
0101 011
1001 100
1001 101
1001 110
The TCM1617 continuously monitors the SDA and SCL
lines for a start condition (a High to Low transition of SDA
while SCL is High), and will not respond until this condition
is met.
Address Byte
Immediately following the Start Condition, the host must
transmit the address byte to the TCM1617. The states of
ADD1 and ADD0 during power-up determine the 7-bit
SMBus address for the TCM1617. The 7-bit address transmitted in the serial bit stream must match for the TCM1617
to respond with an Acknowledge (indicating the TCM1617 is
on the bus and ready to accept data). The eighth bit in the
Address Byte is a Read-Write Bit. This bit is 1 for a read
operation or 0 for a write operation.
provides the clock signal for all transfers. The TCM1617
always operates as a slave. The serial protocol is illustrated
in Figure 3. All data transfers have two phases; all bytes are
transferred MSB first. Accesses are initiated by a start
condition (START), followed by a device address byte and
Acknowledge (ACK)
TCM1617 Serial Bus Conventions
Term
Transmitter
Receiver
Master
Slave
Start
Stop
ACK
Busy
NOT Busy
Data Valid
TCM1617-1
2/5/99
Acknowledge (ACK) provides a positive handshake
between the host and the TCM1617. The host releases SDA
after transmitting eight bits, then generates a ninth clock
cycle to allow the TCM1617 to pull the SDA line Low to
acknowledge that it successfully received the previous eight
bits of data or address.
Explanation
The device sending data to the bus.
The device receiving data from the bus.
The device which controls the bus: initiating
transfers (START), generating the clock, and
terminating transfers (STOP).
The device addressed by the master.
A unique condition signaling the beginning of
a transfer indicated by SDA falling (High – Low)
while SCL is high.
A unique condition signaling the end of a
transfer indicated by SDA rising (Low – High)
while SCL is high.
A receiver acknowledges the receipt of each
byte with this unique condition. The receiver
drives SDA low during SCL high of the ACK
clock-pulse. The Master provides the clock
pulse for the ACK cycle.
Communication is not possible because the
bus is in use.
When the bus is idle, both SDA and SCL
will remain high.
The state of SDA must remain stable during
the High period of SCL in order for a data bit to
be considered valid. SDA only changes state
while SCL is low during normal data transfers
(see Start and Stop conditions.)
Data Byte
After a successful ACK of the address byte, the host
must next transmit the data byte to be written or clock out the
data to be read. (See the appropriate timing diagrams.) ACK
will be generated after a successful write of a data byte into
the TCM1617.
8
 2001 Microchip Technology Inc.
DS21485A
SMBus Thermal Sensor with External Diode Input
TCM1617
Write Byte Format
S
ADDRESS
WR
ACK
COMMAND
7 Bits
ACK
DATA
8 Bits
Slave Address
ACK
P
8 Bits
Command Byte: selects
which register you are
writing to.
Data Byte: data goes
into the register set
by the command byte.
Read Byte Format
S ADDRESS WR ACK COMMAND ACK S
7 Bits
Slave Address
ADDRESS RD ACK DATA NACK P
7 Bits
8 Bits
Command Byte: selects
which register you are
reading from.
Send Byte Format
Data Byte: reads from
the register set by the
command byte.
Receive Byte Format
S ADDRESS WR ACK COMMAND ACK P
7 Bits
8 Bits
Slave Address: repeated
due to change in dataflow direction.
S
ADDRESS RD ACK DATA NACK P
7 Bits
8 Bits
Command Byte: sends
command with no data,
usually used for one-shot
command.
8 Bits
Data Byte: reads data from
the register commanded by
the last Read Byte.
S = Start Condition
P = Stop Condition
Shaded = Slave Transmission
Figure 3. SMBus Protocols
 2001 Microchip Technology Inc.
DS21485A
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TCM1617-1 2/5/99
SMBus Thermal Sensor with External Diode Input
TCM1617
Stop Condition (STOP)
Configuration Register (Config), 8-Bits,
Read/Write
Communications must be terminated by a stop condition (a Low to High transition of SDA while SCL is High). The
Stop Condition must be communicated by the transmitter to
the TCM1617. (Refer to TCN75 data sheet for serial bus
timing diagrams.)
Configuration Register (Config)
D[7]
D[6]
D[5]
Mask1 Chip Stop
REGISTER SET AND PROGRAMMER’S
MODEL
TCM1617 Command Set
Bit
The TCM1617 supports four SMBus command protocols. These are READ_BYTE, WRITE_BYTE, SEND_BYTE,
and RECEIVE_BYTE. See System Management Bus Specification Rev. 1.0 for details.
Code
00h
01h
02h
03h
04h
RIHL
05h
RILL
REHL
06h
07h
RELL
08h
WC
WCR
09h
0Ah
WIHL
0Bh
WILL
WEHL
0Ch
0Dh
WELL
0Eh
OSHT
RMID
RMREV
0Fh
FEh
FFh
Function
Read Internal Temp (INT_TEMP)
Read External Temp (EXT_TEMP)
Read Status Byte (STATUS)
Read Configuration Byte (CONFIG)
Read Conversion Rate Byte
(CONV_RATE)
Read Internal High Limit
(INT_HLIM)
Read Internal Low Limit (INT_LLIM)
Read External High Limit
(EXT_HLIM)
Read External Low Limit
(EXT_LLIM)
Write Configuration Byte (CONFIG)
Write Conversion Rate Byte
(CONV_RATE)
Write Internal High Limit
(INT_HLIM)
Write Internal Low Limit (INT_LLIM)
Write External High Limit
(EXT_HLIM)
Write External Low Limit
(EXT_LLIM)
One Shot Temp Measurement
Read Manufacturer ID (MFR_ID)
Read Manufacturer Revision
Number (MFR_REV)
D[7]
0
Interrupt Mask
(see text)
D[6]
0
Standby switch
D[5] – D[0]
0
Reserved –
Always returns
zero when read.
2/5/99
D[1]
D[0]
Operation
1 = mask ALERT#,
0 = don’t mask
ALERT #
1 = standby,
0 = normal
N/A
A/D Conversion Rate Register
(CONV_RATE), 8-Bits, Read/Write
A/D Conversion Rate Register (CONV_RATE)
D[7]
Bit
D[6]
D[5] D[4]
Reserved
D[3]
D[2]
MSB
POR State Function
D[7:3]
0
D[2:0]
010b
Reserved – Always
returns zero when
read.
Conversion rate bits.
D[1]
X
D[0]
LSB
Operation
N/A
See below.
A/D Conversion Rate Selection
D2
D1
D0
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
Conversion Rate
Sa/sec
0.0625
0.125
0.25
0.5
1.0
2.0
4.0
8.0
NOTE: Conversion rate denotes actual sampling of both internal and
external sensors.
NOTE: Proper device operation is NOT guaranteed if undefined locations
(10h to FDh) are addressed. In case of erroneous SMBus operation
(RECEIVE_BYTE command issued immediately after
WRITE_BYTE command) the TCM1617 will ACKnowledge the
address and return 1111 1111b to signify an error. Under no
condition will it implement an SMBus “timeout.”
TCM1617-1
D[3]
D[2]
Reserved
POR State Function
Command Byte Description
Command
RIT
RET
RS
RC
RCR
D[4]
10
 2001 Microchip Technology Inc.
DS21485A
SMBus Thermal Sensor with External Diode Input
TCM1617
Temperature Threshold Setpoint Registers,
8-Bits, Read-Write (INT_HLIM, INT_LLIM,
EXT_HLIM, EXT_LLIM)
Temperature Registers, 8-Bits, Read-Only
(INT_TEMP, EXT_TEMP)
The binary value (2’s complement format) in these two
registers represents temperature of the internal and external
sensors following a conversion cycle. The registers are
automatically updated in an alternating manner.
These registers store the values of the upper and lower
temperature setpoints for event detection. The value is in
2’s-complement binary. INT_HLIM and INT_LLIM are compared with the INT_TEMP value, and EXT_HLIM and
EXT_LLIM are compared with EXT_TEMP. These registers
may be written at any time.
Internal Temperature Register (INT_TEMP)
D[7]
MSB
D[6]
x
D[5]
x
D[4]
x
D[3]
x
D[2]
x
D[1]
x
External Temperature Register (EXT_TEMP)
D[7]
D[6]
D[5]
D[4]
D[3]
D[2] D[1]
MSB
x
x
x
x
x
x
D[0]
LSB
Internal High Limit Setpoint Register (INT_HLIM)
D[7]
MSB
D[0]
LSB
 2001 Microchip Technology Inc.
DS21485A
Binary
Value
01111111
01111111
01111111
00011001
00000001
00000000
00000000
00000000
00000000
11111111
11111111
11100111
11100110
11001001
11001001
10111111
D[4]
x
D[3]
x
D[2]
x
D[1]
x
D[0]
LSB
External High Limit Setpoint Register (EXT_HLIM)
D[7]
MSB
Temperature-to-Digital Value Conversion
(INT_TEMP, EXT_TEMP, INT_HLIM, INT_LLIM,
EXT_HLIM, EXT_LLIM)
Rounded
Temperature
+127°C
+127°C
+127°C
+25°C
+1°C
0°C
0°C
0°C
0°C
–1°C
–1°C
–25°C
–25°C
–55°C
–55°C
–65°C
D[5]
x
Internal Low Limit Setpoint Register (INT_LLIM)
D[7]
D[6]
D[5]
D[4]
D[3]
D[2] D[1] D[0]
MSB
x
x
x
x
x
x
LSB
In the two temperature data and four threshold setpoint
registers, each unit value represents one degree (Celsius).
The value is in 2’s-complement binary format such that a
reading of 00000000b corresponds to 0°C. Examples of this
temperature-to-binary value relationship are shown in the
following table.
Actual
Temperature
+130.00°C
+127.00°C
+126.50°C
+25.25°C
+0.50°C
+0.25°C
0.00°C
–0.25°C
–0.50°C
–0.75°C
–1.00°C
–25.00°C
–25.25°C
–54.75°C
–55.00°C
–65.00°C
D[6]
x
D[6]
x
D[5]
x
D[4]
x
D[3]
x
D[2]
x
D[1]
x
D[0]
LSB
External Low Limit Setpoint Register (EXT_LLIM)
D[7]
MSB
Hex
Value
7F
7F
7F
19
01
00
00
00
00
FF
FF
E7
E7
C9
C9
BF
D[6]
x
D[5]
x
NOTE: POR states:
INT_HLIM
INT_LLIM
EXT_HLIM
EXT_LLIM
11
D[4]
x
D[3]
x
01111111b
11001001b
01111111b
11001001b
D[2]
x
D[1]
x
D[0]
LSB
+127°C
–55°C
+127°C
–55°C
TCM1617-1 2/5/99
SMBus Thermal Sensor with External Diode Input
TCM1617
Register Set Summary:
Status Register (Status), 8-Bits, Read Only:
Status Register (Status)
D[7]
Busy
D[6]
Flag1
Bit
POR
State
D[7]
0
D[6]
0
D[5]
0
D[4]
0
D[3]
0
D[2]
0
D[1:0]
0
D[5]
D[4]
Flag2 Flag3
D[3]
D[2]
Flag4 Flag5
The TCM1617’s register set is summarized below. All
registers are 8-bits wide.
D[1] D[0]
Reserved
Name
INT_TEMP
Function
Operation*
Signal A/D
converter is busy.
Interrupt flag for
INT_HLIM event
Interrupt flag for
INT_LLIM event
Interrupt flag for
EXT_HLIM event
Interrupt flag for
EXT_LLIM event
External diode
“fault” flag
Reserved –
Always
returns zero.
1 = A/D busy,
0 = A/D idle
1 = interrupt occurred,
0 = none
1 = interrupt occurred,
0 = none
1 = interrupt occurred,
0 = none
1 = interrupt occurred,
0 = none
1 = external diode fault,
0 = external diode OK
N/A
Manufacturer’s Identification Register
(MFR_ID), 8-Bits, Read Only:
Manufacturer’s Identification Register (MFR_ID)
D[6]
X
D[5]
X
D[4]
X
D[3]
X
D[2]
X
D[1]
X
POR
State
Internal sensor
temperature
(2’s complement)
EXT_TEMP External sensor
temperature
(2’s complement)
STATUS
STATUS register
CONFIG
CONFIG register
CONV_RATE A/D conversion
rate register
INT_HLIM
Internal high
limit
(2’s complement)
INT_LLIM
Internal low
limit
(2’s complement)
EXT_HLIM
External high
limit
(2’s complement)
EXT_LLIM
External low
limit
(2’s complement)
MFR_ID
ASCII for letter “T”
(Microchip)
MFR_REV
Serial device
revision#
NOTE: All status bits are cleared after a read operation is performed on
STATUS. The EXT_TEMP register will read +127°C if an external
diode “open” is detected.
D[7]
MSB
Description
Read Write
0000 0000b*
✓
0000 0000b*
✓
0000 0000b
0000 0000b
0000 0010b
✓
✓
✓
✓
✓
0111 1111b
✓
✓
1100 1001b
✓
✓
0111 1111b
✓
✓
1100 1001b
✓
✓
0101 0100b
✓
**
✓
NOTE: *The INT_TEMP and EXT_TEMP register immediately will be
updated by the A/D converter after POR. If STBY# is low at powerup, INT_TEMP and EXT_TEMP will remain in POR state (0000
0000b). **MFR_REV will sequence 01h, 02h, 03h, etc. by masking changes.
D[0]
LSB
Manufacturer’s Revision Register
(MFR_REV), 8-Bits, Read Only:
Manufacturer’s Revision Register (MFR_REV)
D[7]
MSB
D[6]
X
TCM1617-1
2/5/99
D[5]
X
D[4]
X
D[3]
X
D[2]
X
D[1]
X
D[0]
LSB
12
 2001 Microchip Technology Inc.
DS21485A
SMBus Thermal Sensor with External Diode Input
TCM1617
PACKAGE DIMENSIONS
16-Pin QSOP (Narrow)
PIN 1
.157 (3.99)
.150 (3.81) .244 (6.20)
.228 (5.80)
.196 (4.98)
.189 (4.80)
.010 (0.25)
.004 (0.10)
.069 (1.75)
.053 (1.35)
.025
(0.635)
TYP.
8°
MAX.
.012 (0.31)
.008 (0.21)
.010 (0.25)
.007 (0.19)
.050 (1.27)
.016 (0.41)
Dimensions: inches (mm)
 2001 Microchip Technology Inc.
DS21485A
13
TCM1617-1 2/5/99
SMBus Thermal Sensor with External Diode Input
TCM1617
WORLDWIDE SALES AND SERVICE
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All rights reserved. © 2001 Microchip Technology Incorporated. Printed in the USA. 1/01
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Printed on recycled paper.
01/09/01
Information contained in this publication regarding device applications and the like is intended through suggestion only and may be superseded by
updates. It is your responsibility to ensure that your application meets with your specifications. No representation or warranty is given and no liability is
assumed by Microchip Technology Incorporated with respect to the accuracy or use of such information, or infringement of patents or other intellectual
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TCM1617-1
2/5/99
14
 2001 Microchip Technology Inc.
DS21485A