TC77
Thermal Sensor with SPI Interfa
ce
Features
• Digital Temperature Sensing in 5-Pin SOT-23A
and 8-Pin SOIC Packages
• Outputs Temperature as a 13-Bit Digital Word
• SPI and MICROWIRE™ Compatible Interface
• Solid State Temperature Sensing
• ±1°C (max.) accuracy from +25°C to +65°C
• ±2°C (max.) accuracy from -40°C to +85°C
• ±3°C (max.) accuracy from -55°C to +125°C
• 2.7V to 5.5V Operating Range
• Low Power
- 250 µA (typ.) Continuous Conversion Mode
- 0.1 µA (typ.) Shutdown Mode
Description
The TC77 is a serially accessible digital temperature
sensor particularly suited for low cost and small form-
factor applications. Temperature data is converted from
the internal thermal sensing element and made avail-
able at anytime as a 13-bit two’s compliment digital
word. Communication with the TC77 is accomplished
via a SPI and MICROWIRE compatible interface. It has
a 12-bit plus sign temperature resolution of 0.0625°C
per Least Significant Bit (LSb). The TC77 offers a tem-
perature accuracy of ±1.0°C (max.) over the tempera-
ture range of +25°C to +65°C. When operating, the
TC77 consumes only 250 µA (typ.). The TC77’s Con-
figuration register can be used to activate the low
power Shutdown mode, which has a current consump-
tion of only 0.1 µA (typ.). Small size, low cost and ease
of use make the TC77 an ideal choice for implementing
thermal management in a variety of systems.
Typical Applications
• Thermal Protection for Hard Disk Drives and
Other PC Peripherals
• PC Card Devices for Notebook Computers
• Low Cost Thermostat Controls
• Industrial Control
• Office Equipment
• Cellular Phones
• Thermistor Replacement
Package Types
SOT-23-5
CS
V
SS
SCK
1
V
DD
SI/O
SCK
1
SOIC
V
DD
CS
TC77
SI/O
NC
V
SS
TC77
NC
NC
Block Diagram
Typical Application
V
DD
Internal
Diode
Temperature
Sensor
TC77
0.1µF
V
DD
Manufacturer
ID Register
CS
SI/O
SCK
TC77
PIC
®
MCU
V
DD
13-Bit
Sigma Delta
A/D Converter
CS
SCK
SI/O
V
SS
AN0
SCK
SDI
Temperature
Register
V
SS
Serial
Port
Interface
Configuration
Register
2002-2012 Microchip Technology Inc.
DS20092B-page 1
TC77
1.0
1.1
ELECTRICAL
CHARACTERISTICS
Absolute Maximum Ratings †
PIN FUNCTION TABLE
Name
SI/O
SCK
V
SS
CS
NC
V
DD
Serial Clock
Ground
Chip Select (Active-Low)
No Connection
Power Supply
Function
Serial Data Pin
V
DD
........................................................................6.0V
All inputs and outputs w.r.t. V
SS
..... -0.3V to V
DD
+0.3V
Storage temperature ..........................-65°C to +150°C
Ambient temp. with power applied .....-55°C to +125°C
Junction Temperature......................................... 150°C
ESD protection on all pins:
Human Body Model (HBM)..............................>4 kV
Machine Model (MM) ......................................>200V
† 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
operation listings of this specification is not implied. Exposure
to maximum rating conditions for extended periods may affect
device reliability.
DC CHARACTERISTICS
Electrical Specifications:
Unless otherwise noted, all parameters apply at V
DD
= 2.7V to 5.5V and
T
A
= -55°C to +125°C.
Parameters
Power Supply
Operating Voltage Range
Operating Current
Power-On Reset Threshold
Standby Supply Current
Temperature to Bits Converter
Resolution
Temperature Conversion Time
Temperature Accuracy
(Note
1)
t
CT
T
ERR
—
—
-1.0
-2.0
-3.0
13
300
—
—
—
—
400
+1.0
+2.0
+3.0
Bits
ms
°C
+25°C < T
A
< +65°C
-40°C < T
A
< +85°C
-55°C < T
A
< +125°C
TC77-3.3MXX:
V
DD
= 3.3V
TC77-5.0MXX:
V
DD
= 5.0V
ADC LSb = 0.0625°C/bit
(Note 4)
V
DD
I
DD
V
POR
I
DD-
STANDBY
Sym
Min
2.7
—
1.2
—
Typ
—
250
1.6
0.1
Max
5.5
400
2.2
1.0
Units
V
µA
V
µA
Note 1
Conditions
Continuous Temperature
Conversion Mode
V
DD
falling or rising edge
Shutdown Mode
Note 1:
The TC77-3.3MXX and TC77-5.0MXX will operate from a supply voltage of 2.7V to 5.5V. However, the tem-
perature accuracy of the TC77-3.3MXX and TC77-5.0MXX is specified at the nominal operating voltages of
3.3V and 5.0V, respectively. As V
DD
varies from the nominal operating value, the accuracy may be
degraded (Refer to Figures 2-6 and 2-7).
2:
All time measurements are measured with respect to the 50% point of the signal.
3:
Load Capacitance, C
L
= 80 pF, is used for AC timing measurements of output signals.
4:
Resolution = Temperature Range/No. of Bits = (+255°C – -256°C) / (2
13
)
Resolution = 512/8192 = 0.0625°C/Bit
DS20092B-page 2
2002-2012 Microchip Technology Inc.
TC77
DC CHARACTERISTICS (CONTINUED)
Electrical Specifications:
Unless otherwise noted, all parameters apply at V
DD
= 2.7V to 5.5V and
T
A
= -55°C to +125°C.
Parameters
Digital Input/Output
High Level Input Voltage
Low Level Input Voltage
High Level Output Voltage
Low Level Output Voltage
Input Current
V
IH
V
IL
V
OH
V
OL
I
IN(0),
I
IN(1)
0.7 V
DD
-0.3
2.4
—
-1.0
-1.0
0.35
C
IN
, C
OUT
I
O_LEAK
—
-1.0
—
—
—
—
—
—
—
0.8
20
—
—
V
DD
+ 0.3
0.3 V
DD
—
0.4
+1.0
+1.0
—
—
—
+1.0
V
V
V
V
µA
I
OH
= -400 µA
I
OL
= +2 mA
V
IN
= GND
V
IN
= V
DD
SI/O, SCK
Sym
Min
Typ
Max
Units
Conditions
Input Hysteresis
Pin Capacitance
Tri-state Output Leakage
Current
V
pF
µA
V
O
= GND
V
O
= V
DD
Serial Port AC Timing (Notes 2, 3)
Clock Frequency
CS Fall to First Rising SCK
Edge
CS Low to Data Out Delay
SCK Fall to Data Out Delay
CS High to Data Out
Tri-state
SCK High to Data In Hold Time
Data In Set-up Time
Thermal Package Resistance
Thermal Resistance, SOT23-5
Thermal Resistance, 8L-SOIC
JA
JA
—
—
230
163
—
—
°C/W
°C/W
f
CLK
t
CS-SCK
t
CS-SI/O
t
DO
t
DIS
t
HD
t
SU
DC
100
—
—
—
50
30
—
—
—
—
—
—
—
7.0
—
70
100
200
—
—
MHz
ns
ns
ns
ns
ns
ns
Note 1:
The TC77-3.3MXX and TC77-5.0MXX will operate from a supply voltage of 2.7V to 5.5V. However, the tem-
perature accuracy of the TC77-3.3MXX and TC77-5.0MXX is specified at the nominal operating voltages of
3.3V and 5.0V, respectively. As V
DD
varies from the nominal operating value, the accuracy may be
degraded (Refer to Figures 2-6 and 2-7).
2:
All time measurements are measured with respect to the 50% point of the signal.
3:
Load Capacitance, C
L
= 80 pF, is used for AC timing measurements of output signals.
4:
Resolution = Temperature Range/No. of Bits = (+255°C – -256°C) / (2
13
)
Resolution = 512/8192 = 0.0625°C/Bit
2002-2012 Microchip Technology Inc.
DS20092B-page 3
TC77
Data Output Timing
CS
t
CS-SCK
1/f
CLK
SCK
t
CS-SI/O
t
DO
t
DIS
HI-Z
SI/O
HI-Z
MSb
LSb
SI/O Data Input Set-up and Hold Timing (Data is clocked on the rising edge of SCK)
CS
CS
SCK
SCK
t
HD
SI/O
t
SU
HI-Z
SI/O
t
HD
t
SU
HI-Z
FIGURE 1-1:
Timing Diagrams.
DS20092B-page 4
2002-2012 Microchip Technology Inc.
TC77
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 indicated, all parameters apply at V
DD
= 3.3V for the TC77-3.3MXX and V
DD
= 5.0V for the TC77-
5.0MXX, and T
A
= -55°C to +125°C. The TC77-3.3MXX and TC77-5.0MXX will operate from a supply voltage of 2.7V
to 5.5V. However, the temperature accuracy of the TC77-3.3MXX and TC77-5.0MXX is specified at the nominal oper-
ating voltages of 3.3V and 5.0V, respectively.
3.5
3
2.5
2
1.5
1
0.5
0
-0.5
-1
-1.5
-2
-2.5
-3
-3.5
Temperature Error (°C)
Mean + 3V
Mean
Shutdown Current (µA)
Upper Specification Limit
0.3
0.2
TC77-3.3MXX
V
DD
= 3.3 V
TC77-5.0MXX
V
DD
= 5.0 V
Mean - 3V
0.1
Lower Specification Limit
-55
-35
-15
5
25
45
65
85
105 125
0.0
-55
-25
5
35
65
95
125
Reference Temperature (°C)
Temperature (°C)
FIGURE 2-1:
(TC77-XXMXX)
.
Accuracy vs. Temperature
FIGURE 2-4:
Temperature.
Shutdown Current vs.
240
230
220
Power-On Reset Voltage (V)
250
Supply Current (µA)
T
A
= +25°C
2.5
2.0
1.5
1.0
0.5
0.0
-55
-25
5
35
65
95
125
Temperature (°C)
T
A
= -55°C
210
T
A
= +125°C
200
2.7
3.1
3.5
3.9
4.3
4.7
5.1
5.5
Supply Voltage (V)
FIGURE 2-2:
Supply Current vs. Supply
Voltage (TC77-XXMXX).
FIGURE 2-5:
Power-On Reset Voltage vs.
Temperature (TC77-XXMXX).
0.4
Temperature Change (°C)
400
Supply Current (µA)
350
300
250
200
150
100
50
0
-55
-25
5
35
65
95
125
TC77-3.3MXX
V
DD
= 3.3 V
TC77-5.0MXX
V
DD
= 5.0 V
0.3
0.2
0.1
0
-0.1
-0.2
-0.3
-0.4
3
TC77-3.3MXX
T
A
= +85°C
T
A
= +25°C
T
A
= -25°C
3.1
3.2
3.3
3.4
3.5
3.6
Temperature (°C)
Supply Voltage (V)
FIGURE 2-3:
Temperature.
Supply Current vs.
FIGURE 2-6:
Temperature Accuracy vs.
Supply Voltage (TC77-3.3MXX).
2002-2012 Microchip Technology Inc.
DS20092B-page 5
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