MCP9805
Memory Module Digital Temperature Sensor
Features
• Meets JEDEC Standard JC42.4 for Mobile
Platform Memory Module Thermal Sensor
• Temperature-to-Digital Converter
• Accuracy with 0.25 °C/LSb Resolution:
- ±1°C (max.) from +75°C to +95°C
- ±2°C (max.) from +40°C to +125°C
- ±3°C (max.) from -20°C to +125°C
• Programmable Temperature Monitor Boundary
• Critical Temperature Output
• Operating Voltage Range: 3.0V to 3.6V
• 2-wire Interface: SMBus/Standard mode I
2
C™
Compatible
• Operating Current: 200 µA (typ.)
• Shutdown Current: 0.1 µA (typ.)
• Available Packages: 2x3 DFN-8, TSSOP-8
Description
Microchip Technology Inc.’s MCP9805 digital tempera-
ture sensor converts temperatures between -40°C and
+125°C to a digital word. This sensor is designed to
meet the JEDEC standard JC42.4 for Mobile Platform
Memory Module Thermal Sensor. This device provides
an accuracy of ±1°C (max.) from a temperature range
of +75°C to +95°C (active range) and ±2°C (max.) from
+40°C to +125°C (monitor range) as defined in the
JEDEC standard.
The MCP9805 comes with user-programmable
registers
that
provide
flexibility
for
DIMM
temperature-sensing applications. The registers allow
user-selectable settings such as Shutdown or
Low-Power modes and the specification of tempera-
ture event and critical output boundaries. When the
temperature changes beyond the specified boundary
limits, the MCP9805 outputs an Event signal. The user
has the option of setting the Event output signal polarity
as either an active-low or active-high comparator
output for thermostat operation, or as a temperature
event interrupt output for microprocessor-based
systems. The Event output can also be configured as a
critical temperature output.
This sensor has a 2-wire industry-standard SMBus
and Standard mode I
2
C compatible (100 kHz bus
clock) serial interface protocol, allowing up to eight sen-
sors to be controlled in a single serial bus. These fea-
tures make the MCP9805 ideal for sophisticated
multi-zone temperature-monitoring applications.
Typical Applications
•
•
•
•
Dual In-line Memory Module (DIMM)
Personal Computers (PCs) and Servers
Hard Disk Drives and Other PC Peripherals
General Purpose Temperature Sensor
Typical Application
Memory Module
Memory
Temperature
Sensor
MCP9805
Package Types
MCP9805
8-Pin DFN (2x3)
A0 1
A1 2
A2 3
GND 4
8 V
DD
7 Event
6 SCLK
5 SDA
SPD*
EEPROM
R
8-Pin TSSOP
R
A0 1
A1 2
A2 3
8 V
DD
7 Event
6 SCLK
5 SDA
3.3 V
DD_SPD
SDA SCLK
Event
GND 4
*
Serial Presence Detect
2005-2013 Microchip Technology Inc.
DS21977C-page 1
MCP9805
1.0
ELECTRICAL
CHARACTERISTICS
†Notice:
Stresses above those listed under “Maximum
ratings” may cause permanent damage to the device. This is
a stress rating only and functional operation of the device at
those or any other conditions above those indicated in the
operational listings of this specification is not implied.
Exposure to maximum rating conditions for extended periods
may affect device reliability.
Absolute Maximum Ratings †
V
DD
....................................................................... 6.0V
Voltage at all Input/Output pins .... GND – 0.3V to 5.5V
Storage temperature ..........................-65°C to +150°C
Ambient temp. with power applied .....-40°C to +125°C
Junction Temperature (T
J
)................................ +150°C
ESD protection on all pins (HBM:MM)....... (4 kV:200V)
Latch-Up Current at each pin ........................ ±200 mA
DC CHARACTERISTICS
Electrical Specifications:
Unless otherwise indicated, V
DD
= 3.0V to 3.6V, GND = Ground and T
A
= -20°C to +125°C.
Parameters
Power Supply
Operating Voltage Range
Operating Current
Shutdown Current
Power-On Reset Threshold (POR)
Power Supply Rejection
V
DD
I
DD
I
SHDN
V
POR
PSR
DC
PSR
AC
Temperature Sensor Accuracy
Accuracy with 0.25 °C/LSb Resolution:
+75°C to +95°C
+40°C to +125°C
-20°C to +125°C
T
A
= -40°C
Internal
ADC
Conversion Time (10-bits + Sign):
0.25 °C/LSb
Event Output (Open-Drain)
High-Level Current (leakage)
Low-Level Voltage
Thermal Response
Response Time (Note):
DFN
TSSOP
Note:
t
RES
t
RES
—
—
0.7
1.5
—
—
s
s
Time to 63% of +22°C (Air)
to +125°C (Oil Bath)
I
OH
V
OL
—
—
—
—
1
0.4
µA
V
V
OH
= 3.6V
I
OL
= 3 mA
t
CONV
—
65
125
ms
17 samples/sec. (typ.)
T
ACY
T
ACY
T
ACY
T
ACY
-1.0
-2.0
-3.0
—
±0.5
±1.0
±2.0
±2
+1.0
+2.0
+3.0
—
°C
°C
°C
°C
Active Temp. Range
Monitor Temp. Range
3.0
—
—
—
—
—
—
200
0.1
2.2
±0.3
±0.5
3.6
500
2
—
—
—
V
µA
µA
V
°C
°C
V
DD
= 3.3V + 150 mVpp
(0 to 1 MHz), T
A
= +25°C
Continuous Operation
Shutdown Mode
V
DD
Falling Edge
Sym
Min
Typ
Max
Unit
Conditions
Thermal response with 1x1 inch dual-sided copper clad.
DS21977C-page 2
2005-2013 Microchip Technology Inc.
MCP9805
DIGITAL INPUT/OUTPUT PIN CHARACTERISTICS
Electrical Specifications:
Unless otherwise indicated, V
DD
= 3.0V to 3.6V, GND = Ground and T
A
= -20°C to +125°C.
Parameters
Input
High-Level Voltage
Low-Level Voltage
Input Current
Output (SDA)
Low-Level Voltage
High-Level Current (leakage)
Low-Level Current
Capacitance
SDA and SCLK Inputs
Hysteresis
V
HYST
—
0.5
—
V
V
OL
I
OH
I
OL
C
IN
—
—
6
—
—
—
—
5
0.4
1
—
—
V
µA
mA
pF
I
OL
= 3 mA
V
OH
= 3.6V
V
OL
= 0.6V
V
IH
V
IL
I
IN
2.1
—
—
—
—
—
—
0.8
±5
V
V
µA
Sym
Min
Typ
Max
Units
Conditions
Serial Input/Output (SCLK, SDA, A0, A1, A2)
Graphical Symbol Description
SDA & SCLK INPUTS
Voltage
Voltage
V
DD
V
DD
V
IH
V
IL
time
Current
Current
I
OL
V
OL
time
SDA OUTPUT
I
IN
time
I
OH
time
2005-2013 Microchip Technology Inc.
DS21977C-page 3
MCP9805
SERIAL INTERFACE TIMING CHARACTERISTICS
Electrical Specifications:
Unless otherwise indicated, V
DD
= 3.0V to 3.6V, GND = Ground, T
A
= -20°C to +125°C,
C
L
= 80 pF and all limits measured to 50% point.
Parameters
Sym
Min
Typ
Max
Units
Conditions
2-Wire SMBus/Standard Mode I
2
C™ Compatible Interface (Note)
Serial Port Clock Frequency
Low Clock
High Clock
Rise Time
Fall Time
Data Setup Before SCLK High
Data Hold After SCLK Low
Start Condition Setup Time
Start Condition Hold Time
Stop Condition Setup Time
Bus Free
Time Out
Note:
f
SC
t
LOW
t
HIGH
t
R
t
F
t
SU-DATA
t
HD-DATA
t
SU-START
t
HD-START
t
SU-STOP
t
B-FREE
t
OUT
10
4.7
4.0
—
—
250
300
4.7
4.0
4.0
4.7
25
—
—
—
—
—
—
—
—
—
—
—
40
100
—
—
1000
300
—
—
—
—
—
—
50
kHz
µs
µs
ns
ns
ns
ns
µs
µs
µs
µs
ms
(V
IL MAX
- 0.15V) to (V
IH MIN
+ 0.15V)
(V
IH MIN
+ 0.15V) to (V
IL MAX
- 0.15V)
The serial interface specification min./max. limits are specified by characterization (not production tested).
Timing Diagram
t
H-START
t
SU-START
SCLK
t
HIGH
t
LOW
t
B-FREE
t
SU-STOP
SDA
t
OUT
t
SU-DATA
START Condition
t
H-DATA
Data Transmission
STOP Condition
t
R
, t
F
TEMPERATURE CHARACTERISTICS
Electrical Specifications:
Unless otherwise indicated, V
DD
= 3.0V to 3.6V, GND = Ground.
Parameters
Temperature Ranges
Specified Temperature Range
Operating Temperature Range
Storage Temperature Range
Thermal Package Resistances
Thermal Resistance, 8L-DFN
Thermal Resistance, 8L-TSSOP
Note 1:
JA
JA
—
—
41
123.7
—
—
°C/W
°C/W
T
A
T
A
T
A
-20
-40
-65
—
—
—
+125
+125
+150
°C
°C
°C
Note 1
Sym
Min
Typ
Max
Units
Conditions
Operation in this range must not cause T
J
to exceed Maximum Junction Temperature (+150°C).
DS21977C-page 4
2005-2013 Microchip Technology Inc.
MCP9805
2.0
Note:
TYPICAL PERFORMANCE CURVES
The graphs and tables provided following this note are a statistical summary based on a limited number of
samples and are provided for informational purposes only. The performance characteristics listed herein
are not tested or guaranteed. In some graphs or tables, the data presented may be outside the specified
operating range (e.g., outside specified power supply range) and therefore outside the warranted range.
Note:
Unless otherwise noted: V
DD
= 3.0V to 3.6V, GND = Ground, C
de_cap
= 0.1 µF
3.0
Temperature Accuracy (°C)
V
DD
= 3.3V to 3.6V
500
450
400
V
DD
= 3.3V to 3.6V
2.0
1.0
0.0
-1.0
-2.0
-3.0
-40
-20
0
20
40
60
T
A
(°C)
80
100
120
I
DD
(µA)
Spec. Limits
350
300
250
200
150
100
-40
-20
0
20
40
60
T
A
(°C)
80
100
120
FIGURE 2-1:
Accuracy.
Average Temperature
FIGURE 2-4:
Temperature.
2.00
Supply Current vs. Ambient
70%
60%
Occurrences
50%
40%
30%
20%
10%
0%
-1.00
-0.75
-0.50
-0.25
0.00
0.25
0.50
0.75
1.00
T
A
= +95°C
V
DD
= 3.3V
120 samples
V
DD
= 3.3V to 3.6V
1.50
I
SHDN
(µA)
1.00
0.50
0.00
-40
-20
0
20
40
60
T
A
(°C )
80
100
120
Temperature Accuracy (°C)
FIGURE 2-2:
Temperature Accuracy
Histogram, T
A
= +95°C.
70%
60%
Occurrences
50%
40%
30%
20%
10%
0%
-1.00
-0.75
-0.50
-0.25
0.00
0.25
0.50
0.75
1.00
T
A
= +75°C
V
DD
= 3.3V
120 samples
FIGURE 2-5:
Shutdown Current vs.
Ambient Temperature.
3
2.5
V
POR
(V)
2
1.5
1
0.5
0
-40
-20
0
20
40
60
T
A
(°C)
80
100
120
Temperature Accuracy (°C)
FIGURE 2-3:
Temperature Accuracy
Histogram, T
A
= +75°C.
FIGURE 2-6:
Power-on Reset Threshold
Voltage vs. Ambient Temperature.
2005-2013 Microchip Technology Inc.
DS21977C-page 5
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