TMP121
TMP123
SBOS273C − JUNE 2003 − REVISED FEBRUARY 2005
1.5°C Accurate Digital Temperature Sensor
with SPI Interface
FEATURES
D
DIGITAL OUTPUT: SPI-Compatible Interface
D
RESOLUTION: 12-Bit + Sign, 0.0625°C
D
ACCURACY:
D
D
D
D
OPERATION TO 150°C
±1.5°C
from −25°C to +85°C (max)
LOW QUIESCENT CURRENT: 50µA (max)
WIDE SUPPLY RANGE: 2.7V to 5.5V
TINY SOT23-6 PACKAGE
DESCRIPTION
The TMP121 and TMP123 are SPI-compatible tempera-
ture sensors available in the tiny SOT23-6 package.
Requiring no external components, the TMP121 and
TMP123 are capable of measuring temperatures within
2°C of accuracy over a temperature range of −40°C to
+125°C. Low supply current, and a supply range from 2.7V
to 5.5V, make the TMP121 and TMP123 excellent
candidates for low-power applications.
The TMP121 and TMP123 are ideal for extended thermal
measurement in a variety of communication, computer,
consumer, environmental, industrial, and instrumentation
applications.
APPLICATIONS
D
D
D
D
D
D
POWER-SUPPLY TEMPERATURE
MONITORING
COMPUTER PERIPHERAL THERMAL
PROTECTION
NOTEBOOK COMPUTERS
CELL PHONES
BATTERY MANAGEMENT
OFFICE MACHINES
Temperature
Diode
Temp.
Sensor
Control
Logic
Temperature
Diode
Temp.
Sensor
Control
Logic
NC
1
6
SO
GND
1
6
SO
GND
2
∆Σ
A/D
Converter
Serial
Interface
5
CS
NC
2
∆Σ
A/D
Converter
Serial
Interface
5
CS
V+
3
OSC
Config.
and Temp.
Register
4
SCK
V+
3
OSC
Config.
and Temp.
Register
4
SCK
TMP121
TMP123
NC = No Connection
(1)
NC = No Connection
(1)
(1) Pins labeled NC should be left floating or connected to GND.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments
semiconductor products and disclaimers thereto appears at the end of this data sheet.
All trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date. Products
conform to specifications per the terms of Texas Instruments standard warranty.
Production processing does not necessarily include testing of all parameters.
Copyright
2003−2005, Texas Instruments Incorporated
www.ti.com
TMP121
TMP123
www.ti.com
SBOS273C − JUNE 2003 − REVISED FEBRUARY 2005
ABSOLUTE MAXIMUM RATINGS
(1)
Power Supply, V+ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7V
Input Voltage(2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −0.3V to +7V
Input Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10mA
Operating Temperature Range . . . . . . . . . . . . . . . −55°C to +150°C
Storage Temperature Range . . . . . . . . . . . . . . . . . −60°C to +150°C
Junction Temperature (TJ max) . . . . . . . . . . . . . . . . . . . . . . +150°C
Lead Temperature (soldering) . . . . . . . . . . . . . . . . . . . . . . . . +300°C
(1) Stresses above these ratings may cause permanent damage.
Exposure to absolute maximum conditions for extended periods
may degrade device reliability. These are stress ratings only, and
functional operation of the device at these or any other conditions
beyond those specified is not supported.
(2) Input voltage rating applies to all TMP121 and TMP123 input
voltages.
This integrated circuit can be damaged by ESD. Texas
Instruments recommends that all integrated circuits be
handled with appropriate precautions. Failure to observe
proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to
complete device failure. Precision integrated circuits may be more
susceptible to damage because very small parametric changes could
cause the device not to meet its published specifications.
ORDERING INFORMATION
(1)
PRODUCT
TMP121
TMP123
PACKAGE-LEAD
SOT23-6
PACKAGE DESIGNATOR
DBV
PACKAGE MARKING
T121
T123
(1) For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI web site
at www.ti.com.
PIN CONFIGURATIONS
Top View
TMP121
(1)
TMP123
(1)
SOT23-6
T121
T123
NC
GND
V+
1
2
3
6
5
4
SO
CS
SCK
GND
NC
V+
1
2
3
6
5
4
SO
CS
SCK
SOT23−6
NC = No Connection
(2)
SOT23−6
NC = No Connection
(2)
Pin 1 orientation is determined by package marking.
(1) Pin 1 of the SOT23-6 package is determined by orienting the package marking as shown.
(2) Pins labeled NC should be left floating or connected to GND.
2
TMP121
TMP123
www.ti.com
SBOS273C − JUNE 2003 − REVISED FEBRUARY 2005
ELECTRICAL CHARACTERISTICS
At TA = −40°C to +125°C and V+ = 2.7V to 5.5V, unless otherwise noted.
TMP121, TMP123
PARAMETER
TEMPERATURE INPUT
Range
Accuracy (temperature error)
−25°C to +85°C
−40°C to +125°C
−40°C to +150°C
vs Supply
Resolution
DIGITAL INPUT/OUTPUT
Input Logic Levels:
VIH
VIL
Input Current, SO, SCK, CS
Output Logic Levels:
VOL SO
VOH SO
Resolution
Input Capacitance, SO, SCK, CS
Conversion Time
Conversion Period(1)
POWER SUPPLY
Operating Range
Quiescent Current
Shutdown Current (TMP121)
Shutdown Current (TMP123)
TEMPERATURE RANGE
Specified Range
Operating Range
Storage Range
Thermal Resistance
q
JA
SOT23-6 Surface-Mount
(1) Period indicates time between conversion starts.
−40
−55
−60
200
+125
+150
+150
°C
°C
°C
°C/W
IQ
ISD
ISD
Serial Bus Inactive
Serial Bus Inactive
Serial Bus Inactive
2.7
35
0.1
0.1
5.5
50
1
3
V
µA
µA
µA
12-Bit
12-Bit
ISINK = 3mA
ISOURCE = 2mA
0.4
(V+)−0.4
12
2.5
240
480
320
640
V
V
Bits
pF
ms
ms
IIN
0V
≤
VIN
≤
V+
0.7(V+)
0.3(V+)
±1
V
V
µA
−0.3
−40
±0.5
±1.0
±1.5
0.1
±0.0625
+0.3
+125
±1.5
±2.0
°C
°C
°C
°C
°C/V
°C
CONDITIONS
MIN
TYP
MAX
UNIT
3
TMP121
TMP123
www.ti.com
SBOS273C − JUNE 2003 − REVISED FEBRUARY 2005
TYPICAL CHARACTERISTICS
At TA = +25°C and V+ = 5.0V, unless otherwise noted.
QUIESCENT CURRENT vs TEMPERATURE
50
V+ = 5V
40
I
SD
(µA)
I
Q
(µA)
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
20
0.2
0.1
Serial Bus Inactive
10
−60 −40 −20
0
20
40
60
80
100
120 140
Temperature (
_
C)
0.0
30
V+ = 2.7V
SHUTDOWN CURRENT vs TEMPERATURE
−
0.1
−60 −40 −20
0
20
40
60
80
100
120 140
Temperature (_ C)
CONVERSION TIME vs TEMPERATURE
400
2.0
1.5
Temperature Error (
_
C)
Conversion Time (ms)
1.0
0.5
0.0
−0.5
−1.0
−1.5
12−Bit Resolution
100
−60 −40 −20
0
20
40
60
80
100
120 140
Temperature (
_
C)
TEMPERATURE ACCURACY vs TEMPERATURE
300
V+ = 5V
200
V+ = 2.7V
3 Typical Units 12−Bit Resolution
−
2.0
−60 −40 −20
0
20 40 60
80 100 120 140 160
Temperature (
_
C)
4
TMP121
TMP123
www.ti.com
SBOS273C − JUNE 2003 − REVISED FEBRUARY 2005
APPLICATIONS INFORMATION
The TMP121 and TMP123 are 12-bit plus sign read-only
digital temperature sensors optimal for thermal
management and thermal protection applications. The
TMP121 and the TMP123 communicate through a serial
interface that is SPI-compatible. Temperature is converted
to a 12-bit plus sign data word with 0.0625°C resolution.
The TMP121 and TMP123 are specified for a temperature
range of −40°C to +125°C, with operation extending from
−55°C to +150°C.
The TMP121 and TMP123 are optimal for low power
applications, with a 0.5s conversion period for reduced
power consumption. The TMP121 and TMP123 are
specified for a supply voltage range of 2.7V to 5.5V, and
also feature a hardware shutdown to provide additional
power savings.
The TMP121 and TMP123 require no external
components for operation, though a 0.1µF supply bypass
capacitor is recommended. Figure 1 shows typical
connections for the TMP121 and TMP123.
TEMPERATURE REGISTER
The Temperature Register of the TMP121 and TMP123 is
a 16-bit, signed read-only register that stores the output of
the most recent conversion. Up to 16 bits can be read to
obtain data and are described in Table 1. The first 13 bits
are used to indicate temperature with bits D2 = 0, and D1,
D0 in a high impedance state. Data format for temperature
is summarized in Table 2. Following power-up or reset, the
Temperature Register will read 0°C until the first
conversion is complete.
D15
T12
D7
T4
D14
T11
D6
T3
D13
T10
D5
T2
D12
T9
D4
T1
D11
T8
D3
T0
D10
T7
D2
0
D9
T6
D1
Z
D8
T5
D0
Z
Table 1. Temperature Register
TEMPERATURE
(°C)
150
125
25
DIGITAL OUTPUT(1)
(BINARY)
0100 1011 0000 0000
0011 1110 1000 0000
0000 1100 1000 0000
0000 0000 0000 1000
0000 0000 0000 0000
1111 1111 1111 1000
1111 0011 1000 0000
HEX
4B00
3E80
0C80
0008
0000
FFF8
F380
V+
V+
0.0625
0
−0.0625
−25
2
NC
(1)
0.1µF
3
SCK
SO
4
6
TMP121
5
2
NC = No Connection
CS
1
1
NC
(1)
SCK
SO
4
6
TMP123
5
3
0.1µF
−55
1110 0100 1000 0000
E480
(1) The last two bits are high impedance and are shown as 00 in the
table.
CS
Table 2. Temperature Data Format
COMMUNICATING WITH THE TMP121
GND
GND
NOTE: (1) Pins labeled NC should be left floating or connected to GND.
Figure 1. Typical Connections of the TMP121 and
TMP123
The sensing device of both the TMP121 and TMP123 is
the chip itself; the die flag of the lead frame is thermally
connected to pin 2 of the TMP121, and of the TMP123.
Thermal paths run through the package leads as well as
the plastic package, and the lower thermal resistance of
metal causes the leads to provide the primary thermal
path. The GND pin (pin 2) of the TMP121 and the NC pin
(pin 2) of the TMP123 are thermally connected to the metal
lead frame, and are the best choice for thermal input.
To maintain accuracy in applications requiring air or
surface temperature measurement, care should be taken
to isolate the package and leads from ambient air
temperature.
The TMP121 and TMP123 continuously convert
temperatures to digital data while CS is high. CS must be
high for a minimum of one conversion time (320ms max)
to update the temperature data. Reading temperature data
from the TMP121 and TMP123 is initiated by pulling CS
low, which will cause any conversion in progress to
terminate, and place the device into analog shutdown.
Quiescent current is reduced to 1µA during analog
shutdown. Once CS is pulled low, temperature data from
the last completed conversion prior to dropping CS is
latched into the shift register and clocked out at SO on the
falling SCK edge. The 16-bit data word is clocked out sign
bit first, followed by the MSB. Any portion of the 16-bit word
can be read before raising CS. The TMP121 and TMP123
typically require 0.25s to complete a conversion and
consume 50µA of current during this period. If CS is held
high for longer than one conversion time period the
TMP121 and TMP123 will go into idle mode for 0.25s,
requiring only 20µA of current. A new conversion begins
every 0.5s. Figure 2 describes the conversion timing for
the TMP121 and TMP123.
5
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