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
•
Includes Internal
and
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 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
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
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16–Pin QSOP
DB SUFFIX
CASE TBD
PRELIMINARY INFORMATION
PIN CONFIGURATION
(Top View)
NC
1
VDD
2
D+
3
16
NC
15
STBY
14
SCL
D–
4
13
NC
MAX1617
NC
5
12
SDA
ADD1
6
GND
7
GND
8
11
ALERT
10
ADD0
9
NC
ORDERING INFORMATION
Device
MAX1617DBR2
Package
16–Pin QSOP
Shipping
2500 Tape/Reel
©
Semiconductor Components Industries, LLC, 1999
1
February, 2000 – Rev. 0
Publication Order Number:
MAX1617/D
MAX1617
FUNCTIONAL BLOCK DIAGRAM
Internal
Sensor
(Diode)
D+
D–
DS
Modulator
Register Set
Int. Temp
Ext.Temp
Status Byte
Config. Byte
Conv. Rate
Ext. Hi Limit
Ext. Lo Limit
Int. Hi Limit
Int. Lo Limit
Control
Logic
ALERT
STBY
SCL
SDA
SMBus
Interface
ADD 0
ADD 1
ABSOLUTE MAXIMUM RATINGS*
Symbol
VDD
Power Supply Voltage
Voltage on Any Pin
TA
Tstg
Operating Temperature Range
Storage Temperature Range
SMBus Input/Output Current
D– Input Current
PD
Maximum Power Dissipation
Parameter
Value
6.0
(GND – 0.3 V) to (VDD + 0.3 V)
–55 to +125
–65 to +150
–1 to +50
±1
330
Unit
V
V
°C
°C
mA
mA
mW
* 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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2
3
4
VDD
D+
D–
Power
Power Supply Input
Bi–Directional
Bi–Directional
Input
Current Source and A/D Positive Input
Current Sink and A/D Negative Input
6, 10
7, 8
11
ADD[1:0]
GND
Address Select Pins (See Address Decode Table)
System Ground
Power
ALERT
SDA
SCL
Output
SMBus Interrupt (SMBALERT) or Comparator Output
SMBus Serial Data
12
14
15
Bi–Directional
Input
Input
—
SMBus Serial Clock
Standby Enable
Not Connected
STBY
NC
1, 5, 9, 13, 16
Pin No.
Symbol
Type
Description
PIN DESCRIPTION
SCL
(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.
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.
ALERT
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.)
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 V
BE
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 0.7V above GROUND.
VDD
Input. Power supply input. See electrical specifications.
GND
Input. Ground return for all MAX1617 functions.
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3
MAX1617
DC ELECTRICAL CHARACTERISTICS
(VDD = 3.3 V, –55°C
≤
TA
≤
125°C, unless otherwise noted.)
Symbol
Power Supply
VDD
VUV–LOCK
VPOR
IDD
IDD
IDD–STANDBY
IDD–STANDBY
IADD–BIAS
ALERT Output
VOL
ADD[1:0] Inputs
VIL
VIH
STBY Input
VIL
VIH
TRES
TIERR
Logic Input Low
Logic Input High
—
VDD x 0.7
—
–2
–3
—
–3
–5
—
—
—
—
54
–35
—
—
VDD x 0.3
—
V
V
°C
°C
—
—
±3
—
—
±5
100
10
0.7
83
—
+2
+3
—
°C
+3
+5
—
—
—
—
112
+35
Logic Input Low
Logic Input High
—
VDD x 0.7
—
—
VDD x 0.3
—
V
V
Output Low Voltage (IOL = 1.0 mA) (3)
—
—
0.4
V
Power Supply Voltage
VDD Undervoltage Lockout Threshold
Power–On Reset Threshold (VDD Falling Edge)
Operating Current
0.25 Conv./Sec Rate SMBus Inactive (1)
Operating Current
2 Conv./Sec Rate SMBus Inactive (1)
Standby Supply Current (SMBus Active)
Standby Supply Current (SMBus Inactive)
ADD[1:0] Bias Current (Power–Up Only)
3.0
2.4
1.0
—
—
—
—
—
—
2.80
1.7
—
—
—
—
160
5.5
2.95
2.3
70
180
100
10
—
V
V
V
Characteristic
Min
Typ
Max
Unit
m
A
m
A
m
A
m
A
m
A
Temp–to–Bits Converter
Basic Temperature Resolution
Internal Diode Temperature
+60°C
≤
TA
≤
+100°C
0°C
≤
TA
≤
+125°C
–55°C
≤
TA
≤
0°C
External Diode Temperature
+60°C
≤
TA
≤
+100°C
0°C
≤
TA
≤
+125°C
–55°C
≤
TA
≤
0°C
External Diode High Source Current
(D+) – (D–) ~ 0.65 V
External Diode Low Source Current
(D+) – (D–) ~ 0.65 V
Source Voltage
Conversion Time
From CHIP STOP to Conv. Complete (2)
Conversion Rate Accuracy
(See Conversion Rate Register Desc.)
1.0
—
TEERR
IDIODE–HIGH
IDIODE–LOW
VD–SOURCE
tCONV
m
A
m
A
V
msec
%
D
CR
2–Wire SMBus Interface
VIH
VIL
VOL
Logic Input High
Logic Input Low
SDA Output Low
IOL = 2 mA (3)
IOL = 4 mA (3)
Input Capacitance SDA, SCL
2.2
—
—
—
—
—
—
—
—
5.0
—
0.8
0.4
0.6
—
pF
V
V
V
ILEAK
I/O Leakage
–1.0
0.1
1.0
m
A
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.
CIN
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4
MAX1617
SMBus PORT AC TIMING
(VDD = 3.3 V, –55°C
≤
(TA = TJ)
≤
125°C; CL = 80 pF, unless otherwise noted.)
Symbol
fSMB
tLOW
tHIGH
tR
tF
tSU(START)
tH(START)
tSU–DATA
tH–DATA
tSU(STOP)
tIDLE
Characteristic
SMBus Clock Frequency
Low Clock Period (10% to 10%)
High Clock Period (90% to 90%)
SMBus Rise Time (10% to 90%)
SMBus Fall Time (90% to 10%)
Start Condition Setup Time (90% SCL to 10% SDA)
(for Repeated Start Condition)
Start Condition Hold Time
Data in Setup Time
Data in Hold Time
Stop Condition Setup Time
Bus Free Time Prior to New Transition
Min
10
4.7
4
—
—
4
4
1,000
1,250
4
4.7
Typ
—
—
—
—
—
—
—
—
—
—
—
Max
100
—
—
1,000
300
—
—
—
—
—
—
Unit
kHz
m
sec
m
sec
nsec
nsec
m
sec
m
sec
nsec
nsec
m
sec
m
sec
SMBUS Write Timing Diagram
A
ILOW
B
IHIGH
C
D
E F
G
H
I
J
K
L
M
SCL
SDA
t SU(START) t H(START)
t SU–DATA
t H–DATA
t SU(STOP) t IDLE
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
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
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
ILOW
B
IHIGH
C
D
E F
G
H
I
J
K
SCL
SDA
t SU(START)
t H(START)
t SU–DATA
t SU(STOP)
t IDLE
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
F = Acknowledge Bit Clocked into Master
G = MSB of Data Clocked into Master
H = LSB of Data Clocked into Master
I = Acknowledge Clock Pulse
J = Stop Condition
K = New Start Condition
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NXP MCU
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