MAXIM MAX1617/D

MAX1617
SMBus Temperature Sensor
with Internal and External
Diode Input
The MAX1617 is a serially programmable temperature sensor
optimized for monitoring modern high performance CPUs with
on–board, integrated temperature sensing diodes. Temperature data is
converted from the CPU’s diode outputs and made available as an
8–bit digital word.
Communication with the MAX1617 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 MAX1617s 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 MAX1617 an ideal choice for
implementing sophisticated system management schemes, such as
ACPI.
Features
•
•
•
•
•
•
•
•
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•
Includes Internal and External Sensing Capability
Outputs Temperature As 8–Bit Digital Word
Solid State Temperature Sensing; 1°C Resolution
3.0–5.5 V Operating Range
Independent Internal and External Threshold Set–Points With
ALERT Interrupt Output
SMBus 2–Wire Serial Interface
Up To 9 MAX1617s May Share the Same Bus
Low Standby Power Mode
Low Power: 70 µA (max) Operating, 10 µA (max) Standby Mode
16–Pin Plastic QSOP Package
Operating Temperature Range: –55°C to +125°C
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16–Pin QSOP
DB SUFFIX
CASE TBD
PRELIMINARY INFORMATION
PIN CONFIGURATION
NC 1
16 NC
VDD 2
D+
15 STBY
14 SCL
3
D– 4
13 NC
NC 5 MAX1617 12 SDA
ADD1 6
11 ALERT
GND 7
10 ADD0
GND 8
9 NC
(Top View)
ORDERING INFORMATION
Device
Package
Shipping
MAX1617DBR2
16–Pin QSOP
2500 Tape/Reel
Typical Applications
• Thermal Protection For Intel “Deschutes” Pentium II and Other
•
•
High Performance CPUs with Integrated On–Board Diode - No
Sensor Mounting Problems!
Accurate Temperature Sensing From Any Silicon Junction Diode
Thermal Management in Electronic Systems: Computers, Network
Equipment, Power Supplies
 Semiconductor Components Industries, LLC, 2001
April, 2001 – Rev. 1
1
Publication Order Number:
MAX1617/D
MAX1617
FUNCTIONAL BLOCK DIAGRAM
Internal
Sensor
(Diode)
D+
D–
Modulator
Control
Logic
ALERT
STBY
Register Set
Int. Temp
Ext.Temp
Status Byte
Config. Byte
Conv. Rate
SCL
SDA
Ext. Hi Limit
SMBus
Interface
Ext. Lo Limit
Int. Hi Limit
ADD 0
ADD 1
Int. Lo Limit
ABSOLUTE MAXIMUM RATINGS*
Rating
Power Supply Voltage
Symbol
Value
Unit
VDD
6.0
V
(GND – 0.3 V) to (VDD + 0.3 V)
V
°C
Voltage on Any Pin
Operating Temperature Range
TA
–55 to +125
Storage Temperature Range
Tstg
–65 to +150
°C
–1.0 to +50
mA
±1.0
mA
330
mW
SMBus Input/Output Current
D– Input Current
Maximum Power Dissipation
PD
* Maximum Ratings are those values beyond which damage to the device may occur.
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2
MAX1617
PIN DESCRIPTION
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Pin No.
Symbol
Type
Description
2
VDD
Power
3
D+
Bi–Directional
Current Source and A/D Positive Input
4
D–
Bi–Directional
Current Sink and A/D Negative Input
6, 10
ADD[1:0]
Input
Power Supply Input
Address Select Pins (See Address Decode Table)
7, 8
GND
Power
System Ground
11
ALERT
Output
SMBus Interrupt (SMBALERT) or Comparator Output
12
SDA
Bi–Directional
SMBus Serial Data
14
SCL
Input
SMBus Serial Clock
15
STBY
Input
Standby Enable
1, 5, 9, 13, 16
NC
–
Not Connected
PIN DESCRIPTION
(NOTE: A pull–up resistor is necessary on ALERT since
it is an open–drain output. Current sourced from the pull–up
Input. SMBus serial clock. Clocks data into and out of the
resistor causes power dissipation and may cause internal
MAX1617.
heating of the MAX1617. To avoid affecting the accuracy of
SDA
internal temperature readings, the pull–up resistors should
Bi–directional. Serial data is transferred on the SMBus in
be made as large as possible.)
both directions using this pin.
SCL
STBY
ADD1, ADD0
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
MAX1617s on a single bus. A match between the
MAX1617’s address and the address specified in the serial
bit stream must be made to initiate communication. Many
SMBus–compatible devices with other addresses may share
the same 2–wire bus. These pins are only active at power–on
reset, and will latch into the appropriate states.
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 MAX1617
unconditionally enters its low–power Standby mode. The
temperature–to–digital conversion process is halted, but
ALERT remains functional. The MAX1617’s bus interface
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.)
ALERT
D+
Output, Open Collector, Active Low. The ALERT output
corresponds to the general SMBALERT signal and indicates
an interrupt event. The MAX1617 will respond to the
standard SMBus Alert Response Address when ALERT is
asserted. Normally, the ALERT output will be asserted when
any of the following occurs:
INT_TEMP equal to or exceeds INT_HLIM
INT_TEMP falls below INT_LLIM
EXT_TEMP equal to or exceeds EXT_HLIM
EXT_TEMP falls below EXT_LLIM
External Diode “Open”
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.
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 MAX1617, and the
temperature proportional VBE is measured and converted to
digital temperature data.
D–
Bi–directional. This pin connects to the cathode of the
external diode. Current is sunk from the external diode into
the MAX1617 through this pin. It also is the negative input
terminal to the MAX1617’s A/D converter. This node is kept
at approximately 0.7 V above GROUND.
VDD
Input. Power supply input. See electrical specifications.
GND
Input. Ground return for all MAX1617 functions.
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MAX1617
DC ELECTRICAL CHARACTERISTICS (VDD = 3.3 V, –55°C ≤ TA ≤ 125°C, unless otherwise noted.)
Characteristic
Symbol
Min
Typ
Max
Unit
VDD
3.0
–
5.5
V
VUV–LOCK
2.4
2.80
2.95
V
VPOR
1.0
1.7
2.3
V
–
–
70
–
–
180
–
100
A
Power Supply
Power Supply Voltage
VDD Undervoltage Lockout Threshold
Power–On Reset Threshold (VDD Falling Edge)
A
Operating Current
0.25 Conv./Sec Rate SMBus Inactive (1)
IDD
Operating Current
2 Conv./Sec Rate SMBus Inactive (1)
IDD
Standby Supply Current (SMBus Active)
IDD–STANDBY
–
Standby Supply Current (SMBus Inactive)
IDD–STANDBY
–
–
10
A
IADD–BIAS
–
160
–
A
VOL
–
–
0.4
V
ADD[1:0] Bias Current (Power–Up Only)
A
ALERT Output
Output Low Voltage (IOL = 1.0 mA) (3)
ADD[1:0] Inputs
Logic Input Low
VIL
–
–
VDD x 0.3
V
Logic Input High
VIH
VDD x 0.7
–
–
V
STBY Input
Logic Input Low
VIL
–
–
VDD x 0.3
V
Logic Input High
VIH
VDD x 0.7
–
–
V
Basic Temperature Resolution
TRES
–
1.0
–
°C
Internal Diode Temperature
+60°C ≤ TA ≤ +100°C
0°C ≤ TA ≤ +125°C
–55°C ≤ TA ≤ 0°C
TIERR
–2.0
–3.0
–
–
–
±3.0
+2.0
+3.0
–
External Diode Temperature
+60°C ≤ TA ≤ +100°C
0°C ≤ TA ≤ +125°C
–55°C ≤ TA ≤ 0°C
TEERR
–3.0
–5.0
–
–
–
±5.0
+3.0
+5.0
–
Temp–to–Bits Converter
°C
°C
External Diode High Source Current
(D+) – (D–) ~ 0.65 V
IDIODE–HIGH
–
100
–
A
External Diode Low Source Current
(D+) – (D–) ~ 0.65 V
IDIODE–LOW
–
10
–
A
Source Voltage
VD–SOURCE
–
0.7
–
V
Conversion Time
From CHIP STOP to Conv. Complete (2)
tCONV
54
83
112
msec
Conversion Rate Accuracy
(See Conversion Rate Register Desc.)
CR
–35
–
+35
%
Logic Input High
VIH
2.2
–
–
V
Logic Input Low
VIL
–
–
0.8
V
SDA Output Low
IOL = 2 mA (3)
IOL = 4 mA (3)
VOL
–
–
–
–
0.4
0.6
Input Capacitance SDA, SCL
CIN
–
5.0
–
pF
ILEAK
–1.0
0.1
1.0
A
2–Wire SMBus Interface
I/O Leakage
V
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 recurring conversion time see Conversion Rate register description.
3. Output current should be minimized for best temperature accuracy. Power dissipation within the MAX1617 will cause self–heating and
temperature drift error.
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MAX1617
SMBus PORT AC TIMING (VDD = 3.3 V, –55°C ≤ (TA = TJ) ≤ 125°C; CL = 80 pF, unless otherwise noted.)
Characteristic
Symbol
Min
Typ
Max
Unit
SMBus Clock Frequency
fSMB
10
–
100
kHz
Low Clock Period (10% to 10%)
tLOW
4.7
–
–
sec
High Clock Period (90% to 90%)
tHIGH
4.0
–
–
sec
SMBus Rise Time (10% to 90%)
tR
–
–
1,000
nsec
SMBus Fall Time (90% to 10%)
tF
–
–
300
nsec
Start Condition Setup Time (90% SCL to 10% SDA)
(for Repeated Start Condition)
tSU(START)
4.0
–
–
sec
Start Condition Hold Time
tH(START)
4.0
–
–
sec
Data in Setup Time
tSU–DATA
1,000
–
–
nsec
Data in Hold Time
tH–DATA
1,250
–
–
nsec
tSU(STOP)
4.0
–
–
sec
tIDLE
4.7
–
–
sec
Stop Condition Setup Time
Bus Free Time Prior to New Transition
SMBUS Write Timing Diagram
A
B
ILOW
C
IHIGH
D
E F
G
H
I
J
K
L
M
SCL
SDA
t SU(START) t H(START)
t SU–DATA
A = Start Condition
B = MSB of Address Clocked into Slave
C = LSB of Address Clocked into Slave
D = R/W Bit Clocked into Slave
E = Slave Pulls SDA Line Low
t H–DATA
F = Acknowledge Bit Clocked into Master
G = MSB of Data Clocked into Slave
H = LSB of Data Clocked into Slave
I = Slave Pulls SDA Line Low
t SU(STOP) t IDLE
J = Acknowledge Clocked into Master
K = Acknowledge Clock Pulse
L = Stop Condition, Data Executed by Slave
M= New Start Condition
SMBUS Read Timing Diagram
A
B
ILOW
C
IHIGH
D
E F
G
H
I
J
K
SCL
SDA
t SU(START)
t H(START)
t SU–DATA
A = Start Condition
B = MSB of Address Clocked into Slave
C = LSB of Address Clocked into Slave
D = R/W Bit Clocked into Slave
t SU(STOP)
E = Slave Pulls SDA Line Low
F = Acknowledge Bit Clocked into Master
G = MSB of Data Clocked into Master
H = LSB of Data Clocked into Master
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t IDLE
I = Acknowledge Clock Pulse
J = Stop Condition
K = New Start Condition
MAX1617
DETAILED OPERATING DESCRIPTION
The MAX1617 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
MAX1617 die; the other is connected externally. The
external diode may be located on another IC die. The
analog–to–digital converter on the MAX1617 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 MAX1617, which allows for a multi–sensor
configuration. Also, there is low–power Standby mode
where temperature acquisition is suspended.
EXT_TEMP
INT_TEMP
TEMPERATURE
EXT_HLIM
ASSERT
ALERT INT_HLIM
One Shot?
Operating
Mode
0
Don’t Care
Don’t Care
Standby
1
0
Don’t Care
Normal
1
1
No
Standby
1
1
Yes
Normal (1
Conversion
Only, then
Standby)
INT_LLIM
ALERT
Note: This diagram implies that the appropriate setpoint is moved,
temporarily, after each ALERT event to suppress re–assertion
of ALERT immediately after the ARA/de–assertion.
Figure 1. Temperature vs. Setpoint Event Generation
SMBus SLAVE ADDRESS
The two pins ADD1 and ADD0 are tri–state input pins
which determine the 7–bit SMBus slave address of the
MAX1617. The address is latched during POR.
Address Decode Table
ADD0
ADD1
SMBus Address
0
0
0011 000
0
open (3–state)
0011 001
0
1
0011 010
open (3–state)
0
0101 001
open (3–state)
open (3–state)
0101 010
open (3–state)
1
0101 011
1
0
1001 100
1
open (3–state)
1001 101
1
1
1001 110
Standby Mode Operation
Chip Stop Bit
EXT_LLIM
TIME
STANDBY MODE
The MAX1617 allows the host to put it into a low power
(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.
STBY
ASSERT
ALERT
ASSERT
ALERT
SETPOINTS
ASSERT
ALERT
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6
MAX1617
POR*, initialize
all registers
STBY mode
active?
Monitor SMBus
for START
condition
YES
Stop conv.,
reset
STATUS D[7]
NO
Start internal
conversion
STATUS [D7]
YES
YES
One
shot?
YES
YES
NO
NO
READ
Perform one
conversion
cycle
NO
NO
YES
EOC*?
Execute
SMBus
write
YES
Update
INT_TEMP
NO
WRITE
Read/
Write?
NO
NO
Start external
conversion
Execute
SMBus
read
NO
STBY
released?
STBY
active?
Execute
Status read
and clear
STATUS
STATUS
read?
Valid
command?
Address
match?
Thermal
Trip?
NO
YES
ARA*?
YES
YES
STBY
active?
YES
ALERT
active ?
NO
Ext. diode
open?
YES
ARA* bus
arbitration?
YES
NO
YES
NO
Rest
period
over?
NO
YES
One Shot?
NO
EOC*?
YES
YES
Disable and re–arm
ALERT, send
local address to host
Update
EXT_TEMP
NO
NO
Rest Period
according to
CONV_RATE
register
Win
arbitration?
Thermal
Trip?
CONFIG
[D7] active?
YES
YES
NO
Reset
STATUS
bit D[7]
Set appropriate
STATUS bit
D[6:2]
Enable
ALERT#
* POR = Power On Reset; ARA = Alert Response Address; EOC = End Of Conversion
Figure 2. MAX1617 Functional Description Flowchart
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7
MAX1617
Serial Port Operation
Start Condition (START)
The Serial Clock input (SCL) and bi–directional data port
(SDA) form a 2–wire bi–directional serial port for
programming and interrogating the MAX1617. The
following conventions are used in this bus architecture. (See
SMBus Write/Read Timing Diagram.)
All transfers take place under control of a host, usually a
CPU or microcontroller, acting as the Master, which
provides the clock signal for all transfers. The MAX1617
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
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
Acknowledge (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 MAX1617 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. (See SMBus Write/Read Timing Diagram.)
Address Byte
Immediately following the Start Condition, the host must
transmit the address byte to the MAX1617. The states of
ADD1 and ADD0 during power–up determine the 7–bit
SMBus address for the MAX1617. The 7–bit address
transmitted in the serial bit stream must match for the
MAX1617 to respond with an Acknowledge (indicating the
MAX1617 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.
Acknowledge (ACK)
Acknowledge (ACK) provides a positive handshake
between the host and the MAX1617. The host releases SDA
after transmitting eight bits, then generates a ninth clock
cycle to allow the MAX1617 to pull the SDA line Low to
acknowledge that it successfully received the previous eight
bits of data or address.
MAX1617 Serial Bus Conventions
Term
Explanation
Transmitter The device sending data to the bus.
Receiver
Data Byte
The device receiving data from the bus.
Master
The device which controls the bus: initiating
transfers (START), generating the clock, and
terminating transfers (STOP).
Slave
The device addressed by the master.
Start
A unique condition signaling the beginning
of a transfer indicated by SDA falling (High
– Low) while SCL is high.
Stop
A unique condition signaling the end of a
transfer indicated by SDA rising (Low –
High) while SCL is high.
ACK
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.
Busy
Communication is not possible because
the bus is in use.
NOT Busy
When the bus is idle, both SDA and SCL
will remain high.
Data Valid
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).
After a successful ACK of the address byte, the host must
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
MAX1617.
Stop Condition (STOP)
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 MAX1617. (See SMBus Write/Read Timing Diagram.)
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8
MAX1617
Write Byte Format
S
ADDRESS
7 Bits
WR
ACK
Slave Address
Command Byte: selects
which register you
writing to.
Read Byte Format
S
ADDRESS
7 Bits
WR
ACK
Slave Address
COMMAND
8 Bits
ACK
S
Command Byte: selects
which register you
reading from.
ADDRESS RD
7 Bits
ADDRESS
7 Bits
WR
ACK
DATA
8 Bits
P
Data Byte: data goes
into the register set
by the command byte.
ACK
Slave Address: repeated
due to change in data–
flow direction.
Send Byte Format
S
ACK
COMMAND
8 Bits
DATA
8 Bits
NACK
P
Data Byte: reads from
the register set by the
command byte.
Receive Byte Format
ACK
S = Start Condition
P = Stop Condition
Shaded = Slave Transmission
COMMAND
8 Bits
ACK
S
P
ADDRESS RD
7 Bits
Command Byte: sends
command with no data,
usually used for one–shot
command.
REGISTER SET AND PROGRAMMER’S MODEL
MAX1617 Command Set
The MAX1617 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.
Command Byte Description
Code
RIT
00h
Read Internal Temp (INT_TEMP)
RET
01h
Read External Temp (EXT_TEMP)
Function
RS
02h
Read Status Byte (STATUS)
RC
03h
Read Configuration Byte (CONFIG)
RCR
04h
Read Conversion Rate Byte
(CONV_RATE)
RIHL
05h
Read Internal High Limit (INT_HLIM)
RILL
06h
Read Internal Low Limit (INT_LLIM)
REHL
07h
Read External High Limit (EXT_HLIM)
RELL
08h
Read External Low Limit (EXT_LLIM)
WC
09h
Write Configuration Byte (CONFIG)
WCR
0Ah
Write Conversion Rate Byt3
(CONV_RATE)
WIHL
0Bh
Write Internal High Limit (INT_HLIM)
WILL
0Ch
Write Internal Low Limit (INT_LLIM)
WEHL
0Dh
Write External High Limit (EXT_HLIM)
WELL
0Eh
Write External Low Limit (EXT_LLIM)
OSHT
0Fh
One Shot Temp Measurement
RMID
FEh
Read Manufacturer ID (MFR_ID)
RMREV
FFh
Read Manufacturer Revision Number
(MFR_REV)
DATA
8 Bits
NACK
P
Data Byte: reads data from
the register commanded by
the last Read Byte.
Figure 3. SMBus Protocols
Command
ACK
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 MAX1617 will ACKnowledge
the address and return 1111 1111b to signify an error. Under no
condition will it implement an SMBus “timeout.”
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9
MAX1617
Configuration Register (Config), 8–Bits,
Read/Write
reading of 00000000b corresponds to 0°C. Examples of this
temperature–to–binary value relationship are shown in the
following table.
Configuration Register (Config)
D[7]
D[6]
Mask1
Chip Stop
D[5]
D[4]
D[3]
D[2]
D[1]
D[0]
Temperature–to–Digital Value Conversion (INT_TEMP,
EXT_TEMP, INT_HLIM, INT_LLIM,EXT_HLIM,
EXT_LLIM)
Reserved
Bit
POR State
D[7]
0
Function
Operation
Interrupt Mask
(see text)
1 = mask ALERT
0 = don’t mask
ALERT
Actual
Temperature
Rounded
Temperature
Binary
Value
Hex
Value
+130.00°C
+127°C
01111111
7F
+127°C
01111111
7F
D[6]
0
Standby switch
1 = standby,
0 = normal
+127.00°C
+126.50°C
+127°C
01111111
7F
D[5]–D[0]
0
Reserved –
Always returns
zero when read.
N/A
+25.25°C
+25°C
00011001
19
+0.50°C
+1°C
00000001
01
+0.25°C
0°C
00000000
00
0.00°C
0°C
00000000
00
–0.25°C
0°C
00000000
00
–0.50°C
0°C
00000000
00
–0.75°C
–1°C
11111111
FF
A/D Conversion Rate Register (CONV_RATE),
8–Bits, Read/Write
A/D Conversion Rate Register (CONV_RATE)
D[7]
D[6]
D[5]
D[4]
D[3]
Reserved
Bit
POR State
D[7:3]
0
D[2:0]
D[2]
D[1]
D[0]
MSB
X
LSB
Function
Operation
Reserved – Always returns zero when read.
010b
Conversion rate bits.
N/A
See below.
–1.00°C
–1°C
11111111
FF
–25.00°C
–25°C
11100111
E7
–25.25°C
–25°C
11100110
E7
–54.75°C
–55°C
11001001
C9
–55.00°C
–55°C
11001001
C9
–65.00°C
–65°C
10111111
BF
A/D Conversion Rate Selection
D2
D1
D0
0
0
0
0.0625
0
0
1
0.125
0
1
0
0.25
0
1
1
0.5
1
0
0
1.0
1
0
1
2.0
1
1
0
4.0
Temperature Threshold Setpoint Registers,
8–Bits, Read–Write (INT_HLIM, INT_LLIM,
EXT_HLIM, EXT_LLIM)
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.
1
1
1
8.0
Internal High Limit Setpoint Register (INT_HLIM)
Conversion Rate Samples/sec
NOTE: Conversion rate denotes actual sampling of both internal
and external sensors.
D[6]
D[5]
D[4]
D[3]
D[2]
D[1]
D[0]
x
x
x
x
x
x
LSB
D[6]
D[5]
D[4]
D[3]
D[2]
D[1]
D[0]
MSB
x
x
x
x
x
x
LSB
D[4]
D[3]
D[2]
D[1]
D[0]
x
x
x
x
x
LSB
D[7]
D[6]
D[5]
D[4]
D[3]
D[2]
D[1]
D[0]
MSB
x
x
x
x
x
x
LS
D[7]
D[6]
D[5]
D[4]
D[3]
D[2]
D[1]
D[0]
MSB
x
x
x
x
x
x
LSB
External Low Limit Setpoint Register (EXT_LLIM)
External Temperature Register (EXT_TEMP)
D[7]
D[5]
x
External High Limit Setpoint Register (EXT_HLIM)
Internal Temperature Register (INT_TEMP)
D[7]
D[6]
Internal Low Limit Setpoint Register (INT_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.
MSB
D[7]
MSB
D[7]
D[6]
D[5]
D[4]
D[3]
D[2]
D[1]
D[0]
MSB
x
x
x
x
x
x
LSB
NOTE: POR states:
INT_HLIM
INT_LLIM
EXT_HLIM
EXT_LLIM
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
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10
01111111b
11001001b
01111111b
11001001b
+127°C
–55°C
+127°C
–55°C
MAX1617
Status Register (Status)
D[7]
D[6]
D[5]
D[4]
D[3]
D[2]
D[1]
D[0]
Busy
Flag1
Flag2
Flag3
Flag4
Flag5
Flag6
Reserved
Bit(s)
POR
State
D[7]
0
Function
Operation*
Signal A/D
converter is busy.
1 = A/D busy,
0 = A/D idle
Manufacturer’s Identification Register (MFR_ID),
8–Bits, Read Only:
Manufacturer’s Identification Register (MFR_ID)
D[7]
D[6]
D[5]
D[4]
D[3]
D[2]
D[1]
D[0]
MSB
X
X
X
X
X
X
LSB
Manufacturer’s Revision Register (MFR_REV),
8–Bits, Read Only:
Manufacturer’s Revision Register (MFR_REV)
D[6]
0
Interrupt flag for
INT_HLIM event
1 = interrupt occurred,
0 = none
D[5]
0
Interrupt flag for
INT_LLIM event
1 = interrupt occurred,
0 = none
D[4]
0
Interrupt flag for
EXT_HLIM event
1 = interrupt occurred,
0 = none
D[3]
0
Interrupt flag for
EXT_LLIM event
1 = interrupt occurred,
0 = none
D[2]
0
External diode
“fault” flag
1 = external diode fault
0 = external diode OK
D[1:0]
0
Reserved –
Always returns
zero.
N/A
D[7]
D[6]
D[5]
D[4]
D[3]
D[2]
D[1]
D[0]
MSB
X
X
X
X
X
X
LSB
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.
Register Set Summary:
The MAX1617’s register set is summarized in the following table. All registers are 8–bits wide.
Name
Description
POR State
Read
INT_TEMP
EXT_TEMP
Internal sensor temperature (2’s complement)
0000 0000b*
√
External sensor temperature (2’s complement)
0000 0000b*
√
STATUS
STATUS register
0000 0000b
√
CONFIG
CONFIG register
0000 0000b
√
√
CONV_RATE
A/D conversion rate register
0000 0010b
√
√
INT_HLIM
Internal high limit (2’s complement)
0111 1111b
√
√
INT_LLIM
Internal low limit (2’s complement)
1100 1001b
√
√
EXT_HLIM
External high limit (2’s complement)
0111 1111b
√
√
EXT_LLIM
External low limit (2’s complement)
1100 1001b
√
√
MFR_ID
ASCII for letter “T”
0101 0100b
√
MFR_REV
Serial device revision #
**
√
CRITICAL
CRITICAL limit (2’s complement)
N/A
Write
√***
*NOTE: The INT_TEMP and EXT_TEMP register immediately will be updated by the A/D converter after POR. If STBY is low at power–up,
INT_TEMP and EXT_TEMP will remain in POR state (0000 0000b).
**MFR_REV will sequence 01h, 02h, 03h, etc. by mask changes.
***CRITICAL only can be written via the CRIT[1:0] pins. It cannot be accessed through the SMBus port.
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11
MAX1617
PACKAGE DIMENSIONS
16–Pin QSOP
PLASTIC PACKAGE
CASE TBD
ISSUE TBD
PIN 1
.157 (3.99) .244 (6.20)
.150 (3.81) .228 (5.80)
.197 (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)
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are trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes
without further notice to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular
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including without limitation special, consequential or incidental damages. “Typical” parameters which may be provided in SCILLC data sheets and/or
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MAX1617/D