SE95
Ultra high accuracy digital temperature
sensor and thermal Watchdog
Product data sheet
Supersedes data of 2004 Oct 05 2004 Dec 21
INTEGRATED CIRCUITS
Philips Semiconductors Product data sheet
SE95
Ultra high accuracy digital temperature sensor and
thermal Watchdog
2
2004 Dec 21
GENERAL DESCRIPTION
The SE95 is a temperature-to-digital converter using an on-chip
band-gap temperature sensor and Sigma-delta A-to-D conversion
technique. The device is also a thermal detector providing an
over-temp detection output. The SE95 contains a number of data
registers: Configuration register (Conf) to store the device settings
such as sampling rate, device operation mode, OS operation mode,
OS polarity, and OS fault queue as described in the functional
description section; temperature register (Temp) to store the digital
temp reading, and set-point registers (Tos & Thyst) to store
programmable overtemp shutdown and hysteresis limits, and also
an ID register to store manufacturer numbers. These registers are
accessed by a controller via the 2-wire serial I2C-bus interface. The
device includes an open-drain output (OS) which becomes active
when the temperature exceeds the programmed limits. There are
three selectable logic address pins so that eight devices can be
connected on the same bus without address conflict.
The SE95 can be configured for different operation conditions. It can
be set in normal mode to periodically monitor the ambient
temperature, or in shutdown mode to minimize power consumption.
The OS output operates in either of two selectable modes: OS
comparator mode and OS interrupt mode. Its active state can be
selected as either HIGH or LOW. The fault queue that defines the
number of consecutive faults in order to activate the OS output is
programmable as well as the set-point limits.
The temperature register always stores a 13-bit 2’s complement
data giving a temperature resolution of 0.03125 °C. This high
temperature resolution is particularly useful in applications of
measuring precisely the thermal drift or runaway. For normal
operation and compatibility with the LM75A, only the 11 MSBs are
read, with a resolution of 0.125 °C to provide the accuracies
specified. To be compatible with the LM75, read only the 9 MSBs.
The device is powered-up in normal operation mode with the OS in
comparator mode, temperature threshold of 80 °C and hysteresis of
75 °C, so that it can be used as a stand-alone thermostat with those
pre-defined temperature set points. The conversion rate is
programmable, with a default of 10 conversions/sec.
FEATURES
•Pin-for-pin replacement for industry standard LM75/LM75A and
offers improved temperature resolution
•Specification of a single part over power supply range from 2.8 V
to 5.5 V.
•Small 8-pin package types: SO8 and TSSOP8 (MSOP8)
•I2C-bus interface to 400kHz with up to 8 devices on the same bus
•Power supply range from 2.8 V to 5.5 V
•Temperatures range from –55 °C to +125 °C
•13-bit ADC that offers a temperature resolution of 0.03125 °C
•Temperature accuracy of ±1°C from –25 °C to +100 °C
•Programmable temperature threshold and hysteresis set points
•Supply current of 7.0 µA in shut-down mode for power
conservation
•Stand-alone operation as thermostat at power-up
•ESD protection exceeds 1000 V HBM per JESD22-A114,
150 V MM per JESD22-A115
•Latch-up testing is done to JEDEC Standard JESD78 which
exceeds 100 mA
APPLICATIONS
•System thermal management
•Personal computers
•Electronics equipment
•Industrial controllers
ORDERING INFORMATION
Type n mber
Topside mark
Package Temperature
Type
n
u
mber
Topside
mark
Name Description Version
p
range
SE95D SE95 SO8 plastic small outline package; 8 leads; body width 3.9 mm SOT96-1 –55 °C to +125 °C
SE95DP SE95DP TSSOP8 plastic thin shrink small outline package; 8 leads;
body width 3 mm SOT505-1 –55 °C to +125 °C
WATCHDOG is a trademark of National Semiconductor Corporation.
Philips Semiconductors Product data sheet
SE95
Ultra high accuracy digital temperature sensor and
thermal Watchdog
2004 Dec 21 3
PINNING
Pin configuration
1
2
3
45
6
7
8SDA
SCL
OS
GND
VCC
A0
A1
A2
SL01388
Figure 1. SO8 and TSSOP8 pin configurations.
Pin description
PIN SYMBOL DESCRIPTION
1 SDA Digital I/O. I2C serial bi-directional data line.
Open Drain.
2 SCL Digital input. I2C serial clock input.
3 OS Overtemp Shutdown output. Open Drain.
4 GND Ground. To be connected to the system
ground.
5 A2 Digital input. User-defined address bit2.
6 A1 Digital input. User-defined address bit1.
7 A0 Digital input. User-defined address bit0.
8 VCC Power supply.
SIMPLIFIED BLOCK DIAGRAM
OS
A2 A1 A0 SCL GND
BIAS
OSC
POR
SDA
VCC
SL01735
BANDGAP
SIGMA–DELTA
MODULATOR
BIT
STREAM DECIMATION
FILTER
A/D CONTROL AND OTP CONTROL
CONF REG
TEMP REG
TOS REG
THYST REG
REGISTER
BANK
INTERRUPTION
LOGIC
I2C INTERFACE LOGIC
OTP
.
.
.
SE95
Figure 2. Simplified block diagram.
Philips Semiconductors Product data sheet
SE95
Ultra high accuracy digital temperature sensor and
thermal Watchdog
2004 Dec 21 4
TYPICAL APPLICATION CIRCUIT
8
2SCL
1SDA 3SE95 OS
5A2
6A1
7A0
4
GND
I2C-BUS
VCC POWER SUPPLY
BUS
PULL-UP
RESISTORS
DIGITAL LOGIC OR
TIE TO VCC/GND
0.1 µF
10 kΩ
VCC
DETECTOR OR
INTERRUPT LINE
SL01883
Figure 3. Typical application circuit
ABSOLUTE MAXIMUM RATINGS1
SYMBOL PARAMETER MIN. MAX. UNIT
VCC to GND –0.3 6.0 V
Voltage at inputs SCL and SDA –0.3 6.0 V
Voltage at inputs A0, A1, A2 –3.0 VCC + 0.3 V
Current at input pins –5.0 5.0 mA
OS output sink current – 10.0 mA
OS output voltage –0.3 6.0 V
Vesd Human Body Model – 1000 V
Machine Model – 150 V
Tstg Storage temperature range –65 150 °C
TjJunction temperature – 150 °C
NOTE:
1. This is a stress rating only. Functional operation of the device as indicated in the operational section is not applied to this absolute maximum
rating. Stresses above those listed in ‘Absolute Maximum Ratings’ may cause permanent damage to the device and exposure to any of
these rating conditions for extended periods may affect device reliability.
OPERATING RATINGS
SYMBOL PARAMETER MIN. MAX. UNIT
VCC Supply voltage 2.8 5.5 V
Tamb Operating ambient temperature range –55 125 °C
Philips Semiconductors Product data sheet
SE95
Ultra high accuracy digital temperature sensor and
thermal Watchdog
2004 Dec 21 5
DC ELECTRICAL CHARACTERISTICS
VCC = 2.8 V to 5.5 V, Tamb = –55 °C to +125 °C unless otherwise noted.
SYM PARAMETER CONDITIONS MIN. TYP.2MAX. UNIT
TACC Temperature accuracy (Note 1) Tamb = –25 °C to +100 °C –1.0 – +1.0 °C
VCC = 2.8 V to 3.6 V Tamb = –55 °C to +125 °C –2.0 – +2.0 °C
Temperature accuracy (Note 1) Tamb = –25 °C to +100 °C –2 – +2 °C
VCC = 3.6 V to 5.5 V Tamb = –55 °C to +125 °C –3 – +3 °C
TRES Temperature resolution 11-bit digital temp data – 0.125 – °C
TCON Temperature conversion time Normal mode – 33 – ms
IDD Supply quiescent current Normal mode: I2C inactive – 150 – µA
Normal mode: I2C active – – 1.0 mA
Shut-down mode – 7.5 – µA
VIH HIGH-level input voltage Digital pins (SCL, SDA, A2–A0) 0.7 × VCC – VCC + 0.3 V
VIL LOW-level input voltage Digital pins –0.3 – 0.3 × VCC V
VIHYS Input voltage hysteresis SCL and SDA pins – 300 – mV
A2 to A0 pins – 300 – mV
IIH HIGH–level input current Digital pins; VIN = VCC –1.0 – 1.0 µA
IIL LOW-level input current Digital pins; VIN = 0 V –1.0 – 1.0 µA
VOL LOW-level output voltage SDA and OS pins; IOL = 3 mA – – 0.4 V
IOL = 4 mA – – 0.8 V
ILO Output leakage current SDA and OS pins; VOH = VCC – – 10 µA
POR Power-on reset VCC supply below which the logic
is reset 1.0 – 2.5 V
OSQ OS fault queue Programmable 1 – 6 Conv3
Tos Overtemp shutdown Default value – 80 – °C
Sampling rate Programmable 0.125 10 30 sample/s
Thyst Hysteresis Default value – 75 – °C
CIN Input capacitance Digital pins – 20 – pF
NOTE:
1. Assumes a minimum 11-bit temperature reading.
2. Typical values are at VCC = 3.3 V and Tamb = 25 °C.
3. Conv: device A-to-D conversion.
Philips Semiconductors Product data sheet
SE95
Ultra high accuracy digital temperature sensor and
thermal Watchdog
2004 Dec 21 6
I2C INTERFACE AC CHARACTERISTICS1
VCC = 2.8 V to 5.5 V, Tamb = –55 °C to +125 °C unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT
tCLK SCL clock period See timing diagram (Figure 4) 2.5 – – µs
tHIGH SCL HIGH pulse width 0.6 – – µs
tLOW SCL LOW pulse width 1.3 – – µs
tHD:STA Start Hold time 100 – – ns
tSU:DAT Data set–up time 100 – – ns
tHD;DAT Data hold time 0 – – ns
tSU;STO Stop set-up time 100 – – ns
tFFall time (SDA and OS outputs) CL = 400 pF; IOL = 3 mA – 250 – ns
NOTE:
1. These specifications are guaranteed by design and not tested in production.
SL02097
SSr tSU;STO
tHD;STA tHIGH
tLOW tSU;DAT
tHD;DAT
tf
SDA
SCL
PS
tftHD;STA
Figure 4. Timing diagram.
Philips Semiconductors Product data sheet
SE95
Ultra high accuracy digital temperature sensor and
thermal Watchdog
2004 Dec 21 7
PERFORMANCE CURVES
SHUT-DOWN SUPPLY CURRENT ( A)µ
SL02150
TEMPERATURE (°C)
–50 0 25 50 100 125
075–25
5
10
15
20
25
VCC = 2.8 V
VCC = 3.3 V
VCC = 5.5 V
VCC = 3.9 V
Figure 5. T ypical shut-down supply current versus
temperature and VCC
NORMAL SUPPLY CURRENT ( A)µ
SL02152
TEMPERATURE (°C)
–50 0 25 50 100 125
075–25
50
100
150
200
250
300
VCC = 2.8 V
VCC = 3.3 V
VCC = 3.9 V
VCC = 5.5 V
Figure 6. Typical normal I2C inactive supply current versus
temperature and VCC
NORMAL SUPPLY CURRENT ( A)µ
SL02151
TEMPERATURE (°C)
–50 0 25 50 100 125
075–25
50
100
150
200
250 30 Conv./second
300
10 Conv./second
1 Conv./second0.125 Conv./second
Figure 7. Typical normal I2C inactive supply current versus
temperature and conversion rate (VCC = 3.3 V)
SDA V (V)
SL02153
TEMPERATURE (°C)
–50 0 25 50 100 125
0.00 75–25
0.05
0.10
0.15
0.20
0.25
VCC = 2.8 V
VCC = 3.3 V
VCC = 3.9 V
VCC = 5.5 V
OL
Figure 8. Typical SDA VOL versus temperature and VCC
(IOL = 3 mA)
CONVERSION TIME (ms)
SL02154
TEMPERATURE (°C)
–50 0 25 50 100 125
30 75–25
31
32
33
34
35
Figure 9. Typical conversion time versus temperature
(VCC = 2.8 V to 5.5 V)
OS V (V)
SL02155
TEMPERATURE (°C)
–50 0 25 50 100 125
0.00 75–25
0.05
0.10
0.15
0.20
0.25
VCC = 2.8 V
VCC = 3.3 V
VCC = 3.9 V
VCC = 5.5 V
OL
Figure 10. Typical OS VOL versus temperature and VCC
(IOL = 3 mA)
Philips Semiconductors Product data sheet
SE95
Ultra high accuracy digital temperature sensor and
thermal Watchdog
2004 Dec 21 8
FUNCTIONAL DESCRIPTION
General operation
The SE95 uses the on-chip band-gap sensor to measure the device
temperature with the resolution of 0.03125 °C and stores the 13-bit
2’s complement digital data, resulted from 13-bit A-to-D conversion,
into the device Temp register. This Temp register can be read at any
time by a controller on the I2C-bus. Reading temperature data does
not affect the conversion in progress during the read operation.
The device can be set to operate in either mode: normal or
shut-down. In normal operation mode, by default, the temp-to-digital
conversion is executed every 100 ms and the Temp register is
updated at the end of each conversion. In shut-down mode, the
device becomes idle, data conversion is disabled and the Temp
register holds the latest result; however, the device I2C interface is
still active and register write/ read operation can be performed. The
device operation mode is controlled by programming bit B0 of the
configuration register. The temperature conversion is initiated when
the device is powered up or returned to normal mode from
shut-down.
In addition, at the end of each conversion in normal mode, the
temperature data (or Temp) in the Temp register is automatically
compared with the over-temp shut-down threshold data (or Tos)
stored in the Tos register, and the hysteresis data (or Thyst) stored
in the Thyst register, in order to set the state of the device OS output
accordingly. The device Tos and Thyst registers are write/read
capable, and both operate with 9-bit 2’s complement digital data.
To match with this 9-bit operation, the temp register uses only the
9 MSB bits of its 13-bit data for the comparison.
The device temperature conversion rate is programmable and can
be chosen to be one of the four values: 0.125, 1.0, 10, and 30
conversions per second. The default conversion rate is 10
conversions per second. Furthermore, the conversion rate is
selected by programming bits B5 and B6 of the Configuration
Register as shown in Table 3. Note that the average supply current
as well as the device power consumption increase with the
conversion rate.
The way that the OS output responds to the comparison operation
depends upon the OS operation mode selected by configuration
bit B1, and the user-defined fault queue defined by configuration
bits B3 and B4.
In OS comparator mode, the OS output behaves like a thermostat. It
becomes active when the Temp exceeds the Tos, and is reset when
the Temp drops below the Thyst. Reading the device registers or
putting the device into shut-down does not change the state of the
OS output. The OS output in this case can be used to control
cooling fans or thermal switches.
In OS interrupt mode, the OS output is used for thermal interruption.
When the device is powered-up, the OS output is first activated only
when the Temp exceeds the Tos; then it remains active indefinitely
until being reset by a read of any register. Once the OS output has
been activated by crossing Tos and then reset, it can be activated
again only when the Temp drops below the Thyst; then again, it
remains active indefinitely until being reset by a read of any register.
The OS interrupt operation would be continued in this sequence:
Tos trip, Reset, Thyst trip, Reset, Tos trip, Reset, Thyst trip, Reset,
and etc. Putting the device into shut-down mode also resets the OS
output.
In both cases, comparator mode and interrupt mode, the OS output
is activated only if a number of consecutive faults, defined by the
device fault queue, has been met. The fault queue is programmable
and stored in the two bits, B3 and B4, of the Configuration register.
Also, the OS output active state is selectable as HIGH or LOW by
setting accordingly the configuration register bit B2.
At power-up, the device is put into normal operation mode, the Tos
is set to 80 °C, the Thyst is set to 75 °C, the OS active state is
selected LOW and the fault queue is equal to 1. The temp reading
data is not available until the first conversion is completed in about
33 ms.
The OS response to the temperature is illustrated in Figure 11.
Philips Semiconductors Product data sheet
SE95
Ultra high accuracy digital temperature sensor and
thermal Watchdog
2004 Dec 21 9
SL01392
Temp
** *
POWER-UP
TIME
OS RESET
OS ACTIVE
OS OUTPUT IN INTERRUPT MODE
OS OUTPUT IN COMPARATOR MODE
OS RESET
OS ACTIVE
Tos
Thyst
READING TEMPERATURE & LIMITS
* = OS is reset by either reading register or putting the device in shutdown.
Assumed that the fault queue is met at each Tos and Thyst crossing point.
Figure 11. OS response to temperature.
Philips Semiconductors Product data sheet
SE95
Ultra high accuracy digital temperature sensor and
thermal Watchdog
2004 Dec 21 10
I2C serial interface
The SE95 can be connected to a compatible 2-wire serial interface
I2C-bus as a slave device under the control of a controller or master
device, using two device terminals, SCL and SDA. The controller
must provide the SCL clock signal and write/read data to/from the
device through the SDA terminal. Note that if the I2C common
pull-up resistors have not been installed as required for I2C-bus,
then an external pull-up resistor, about 10 kΩ, is needed for each of
these two terminals. The bus communication protocols are
described in the data communication section.
Slave address
The SE95 slave address on the I2C-bus is partially defined by the
logic applied to the device address pins A2, A1 and A0. Each pin is
typically connected either to GND for logic 0, or to VCC for logic 1.
These pins represent the three LSB bits of the device 7-bit address.
The other four MSB bits of the address data are preset to ‘1001’ by
hard wiring inside the SE95. Table 1 shows the device’s complete
address and indicates that up to 8 devices can be connected to the
same bus without address conflict. Because the input pins, SCL,
SDA, A2–A0, are not internally biased, it is important that they
should not be left floating in any application.
Table 1. Address table
1 = HIGH, 0 = LOW
MSB LSB
1 0 0 1 A2 A1 A0
Register list
The SE95 contains 7 data registers. The registers can be 1 byte or
2 bytes wide, and are defined in Table 2. The registers are accessed
by the value in the content of the pointer register during I2C-bus
communication. The types of registers are: read only, read/write,
and reserved for manufacturer use. Note that when reading a
two-byte register, the host must provide enough clock pulses as
required by the I2C protocol (see the “Data communication” section)
for the device to completely return both data bytes. Otherwise the
device may hold the SDA line as LOW state, resulting in a bus hang
condition.
Register pointer
The register pointer or pointer byte is an 8-bit data byte that is
equivalent to the register command in the I2C-bus definitions and is
used to identify the device register to be accessed for a write or read
operation. Its values are listed as pointer values in Table 2, “Register
table”. For the device register I2C-bus communication, the pointer
byte may or may not need to be included within the command as
illustrated in the I2C protocol figures in section “Data
communication” on page 14.
The command statements of writing data to a register must always
include the pointer byte; while the command statements of reading
data from a register may or may not include it. To read a register that
is different from the one that has been recently read, the pointer byte
must be included. However, to re-read a register that has been
recently read, the pointer byte may not have to be included in the
reading.
At power-up, the pointer value is preset to ‘0’ for the Temp Register;
users can then read the temperature without specifying the pointer
byte.
Table 2. Register table
Register name Pointer value R/W POR state Description
Conf 01H R/W 00H Configuration Register .
Contains a single 8-bit data byte. To set an operating condition.
Temp 00H Read only N/A T emperature Register.
Contains two 8-bit data bytes. To store the measured Temp data.
Tos 03H R/W 50 00H Over-temp Shutdown threshold Register.
Contains two 8-bit data bytes. To store the over-temp shut-down Tos limit.
Default = 80 °C.
Thyst 02H R/W 4B 00H Hysteresis Register.
Contains two 8-bit data bytes. To store the hysteresis Thyst limit.
B7–B0 are also used in OTP test mode to supply OTP write data.
Default = 75 °C.
ID 05H Read only A1H ID Register.
Contains a single 8-bit data byte for the manufacturer ID code.
reserved 04H N/A N/A Reserved.
reserved 06H N/A N/A Reserved.
Philips Semiconductors Product data sheet
SE95
Ultra high accuracy digital temperature sensor and
thermal Watchdog
2004 Dec 21 11
Configuration register
The Configuration register is a write/read register and contains an 8-bit non-complement data byte that is used to configure the device for
different operating conditions. The Configuration register table (Table 3) shows the bit assignments of this register.
Table 3. Configuration register table
Bit Name R/W POR Description
B7 Reserved R/W 0 Reserved for manufacturer’s use.
B6–B5 Rate val R/W 00 Sets the conversion rate:
00 = 10 conversions/sec (default)
01 = 0.125 conversions/sec
10 = 1 conversions/sec
11 = 30 conversions/sec
B4–B3 OS Fault queue R/W 0For OS Fault Queue programming.
Programmable queue data = 0, 1 ,2, 3 for queue value = 1, 2, 4, 6 respectively. Default = 0.
B2 OS Polarity R/W 0For OS Polarity selection.
1 = OS active HIGH, 0 = OS active LOW (default).
B1 OS Comp/Interrupt R/W 0For OS operation Mode selection.
1 = OS interrupt, 0 = OS comparator (default).
B0 Shut-down R/W 0For Device Operation Mode selection.
1 = Shut-down, 0 = Normal (default).
Temperature Register (Temp)
The Temp register holds the digital result of temperature measurement or monitor at the end each A-to-D conversion. This register is read only
and contains two 8-bit data bytes consisting of one most significant (MS) data byte and one least significant (LS) data byte. However, only 13
bits of those two bytes are used to store the Temp data in 2’ s complement format with the resolution of 0.03125 °C. The Temp register table
(Table 4) shows the bit arrangement of the Temp data in the data bytes.
Table 4. Temp Register table
Temp MS byte Temp LS byte
MSB LSB MSB LSB
B7 B6 B5 B4 B3 B2 B1 B0 B7 B6 B5 B4 B3 B2 B1 B0
for 11-bit Temp Data Not used
MSB LSB
D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 X X X X X
for 13-bit Temp Data Not used
MSB LSB
D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 X X X
When reading the Temp register, all 16 bits of the two data bytes (MS byte and LS byte) must be collected and then the 2’s complement data
value according to the desired resolution must be selected for the temperature calculation. The Table 4 has shown the examples for two cases:
11-bit 2’ s complement data value, and 13-bit 2’ s complement data value. When converting into the temperature the proper resolut ion must be
used as listed in Table 5 using either one of these two formulae:
1. If the Temp Data MSB = 0, then: Temp Value (°C) = +(Temp Data) × Value Resolution
2. If the Temp Data MSB = 1, then: Temp Value (°C) = –(2’ s complement Temp Data) × Value Resolution
Table 6 shows some examples of the results for the 11-bit calculations.
Table 5. Temp Data and Temp Value resolution
Data resolution Value resolution
8 bits 1.0 °C
9 bits 0.5 °C
10 bits 0.25 °C
11 bits 0.125 °C
12 bits 0.0625 °C
13 bits 0.03125 °C
Philips Semiconductors Product data sheet
SE95
Ultra high accuracy digital temperature sensor and
thermal Watchdog
2004 Dec 21 12
Table 6. Temp table
Temp data Temp value
11–bit Binary (2’ s complement) 3-bit Hex Decimal value °C
0111 1111 000 3F8h 1016 +127.000 °C
0111 1110 111 3F7h 1015 +126.875 °C
0111 1110 001 3F1h 1009 +126.125 °C
0111 1101 000 3E8h 1000 +125.000 °C
0001 1001 000 0C8h 200 +25.000 °C
0000 0000 001 001h 1 +0.125 °C
0000 0000 000 000h 0 0.000 °C
1111 1111 111 7FFh –1 –0.125 °C
1110 01 11 000 738h –200 –25.000 °C
11001001 001 649h –439 –54.875 °C
1100 1001 000 648h –440 –55.000 °C
Obviously, for 9-bit Temp data application in replacing the industry standard LM75, just use only 9 MSB bits of the two bytes and disregard
7 LSB bits of the LS byte. The 9-bit temp data with 0.5 °C resolution of the SE95 is defined exactly in the same way as for the standard LM75
and it is here similar to the Tos and Thyst that is described next.
Overtemp shut-down threshold (Tos) and hysteresis (Thyst) registers
These two registers are write/read registers, and also called set-point registers. They are used to store the user-defined temperature limits,
called overtemp shut-down threshold (Tos) and hysteresis (Thyst), for the device Watchdog operation. At the end of each conversion the Temp
data will be compared with the data stored in these two registers in order to set the state of the device OS output accordingly as described in the
“General operation” section.
Each of the set-point registers contains two 8-bit data bytes consisting of one MS data byte and one LS data byte the same as the Temp
register. However, only 9 bits of the two bytes are used to store the set-point data in 2’s complement format with the resolution of 0.5 °C. The
Tos register table (Table 7) and Thyst register table (Table 8) show the bit arrangement of the Tos data and Thyst data in the data bytes.
Notice that because only 9-bit data are used in the set-point registers, the device uses only the 9 MSB bits of the Temp data for data
comparison.
Table 7. Tos register table
Tos MS byte Tos LS byte
MSB LSB MSB LSB
B7 B6 B5 B4 B3 B2 B1 B0 B7 B6 B5 B4 B3 B2 B1 B0
Tos data (9 bits) Not used
MSB LSB
D8 D7 D6 D5 D4 D3 D2 D1 D0 XXXXXXX
Table 8. Thyst register table
Thyst MS byte Thyst LS byte
MSB LSB MSB LSB
B7 B6 B5 B4 B3 B2 B1 B0 B7 B6 B5 B4 B3 B2 B1 B0
Thyst data (9 bits) Not used
MSB LSB
D8 D7 D6 D5 D4 D3 D2 D1 D0 XXXXXXX
When a set-point register is read, all 16 bits are provided to the bus and must be collected by the controller to complete the bus operation.
However, only the 9 significant bits should be used and the 7 LSB bits of the LS byte are equal to zero and should be ignored.
The Tos and Thyst table (Table 9) shows examples of the limit data and value.
Philips Semiconductors Product data sheet
SE95
Ultra high accuracy digital temperature sensor and
thermal Watchdog
2004 Dec 21 13
Table 9. Tos and Thyst table
Limit data Limit temp value
11–bit Binary (2’ s complement) 3-bit Hex Decimal value °C
0111 1101 0 0FAh 250 +125.0 °C
0001 1001 0 032h 50 +25.0 °C
0000 0000 1 001h 1 +0.5 °C
0000 0000 0 000h 0 0.0 °C
1111 1111 1 1FFh –1 –0.5 °C
1110 0111 0 1CEh –50 –25.0 °C
1100 1001 0 192h –110 –55.0 °C
OS output and polarity
The OS output is an open-drain output and its state represents
results of the device Watchdog operation as described in the
“General operation” section. In order to observe this output state, an
external pull-up resistor is needed. The resistor should be as large
as possible, up 200 kΩ, to minimize the temp reading error due to
internal heating by the high OS sinking current.
The OS output active state can be selected as HIGH or LOW by
programming bit B2 of the Configuration register: setting B2 to 1
selects OS active HIGH and setting B2 to 0 sets OS active LOW.
At power-up, this bit is equal to 0 and the OS active state is LOW.
OS comparator and interrupt modes
As described in the “General operation” section, the device OS
output responds to the result of the comparison between the Temp
data and the programmed limits, Tos and Thyst, in different ways
depending on the selected OS mode: OS comparator or OS
interrupt. The OS mode is selected by programming bit B1 of the
configuration register: setting B1 to 1 selects the OS interrupt mode,
and setting B1 to 0 selects the OS comparator mode. At power up,
this bit is equal to 0 and the OS comparator is selected.
The main dif ference between the two modes is that in OS
comparator mode, the OS output becomes active when the Temp
has exceeded the Tos and reset when the Temp has dropped below
the Thyst, reading a register or putting the device into shut-down
does not change the state of the OS output; while in OS interrupt
mode, once it has been activated either by exceeding the Tos or
dropping below the Thyst, the OS output will remain active
indefinitely until reading a register or putting the device into
shut-down occurs, then the OS output is reset.
The Tos & Thyst limits must be selected so that Tos temp value >
Thyst temp value. Otherwise, the OS output state will be undefined.
OS fault queue
Fault queue is defined as the number of faults that must occur
consecutively to activate the OS output. It is provided to avoid false
tripping due to noise. Because faults are determined at the end of
data conversions, fault queue is also defined as the number of
consecutive conversions returning a temperature trip. The value of
fault queue is selectable by programming the two bits B4 and B3 of
the configuration register. Notice that the programmed data and the
fault queue value are not the same. The Fault queue table
(Table 10) shows the one-to-one relationship between them. At
power-up, fault queue data = 0 and fault queue value = 1.
Table 10. Fault queue table
Fault queue data Fault queue value
B4 B3 Decimal
0 0 1
0 1 2
1 0 4
1 1 6
Shutdown mode
The device operation mode is selected by programming bit B0 of the
Configuration register: Setting B0 to 1 will put the device into
shut-down mode. Resetting B0 to 0 will return the device to normal
mode.
In shut-down mode, the device draws a small current of about
7.5 µA and the power dissipation is minimized; the temperature
conversion stops, but the I2C interface remains active and register
write/read operation can be performed. If the OS output is in
comparator mode, then it remains unchanged. In Interrupt mode, the
OS output is reset.
Power-up default and Power-on Reset
The SE95 always powers-up in its default state with:
– Normal operation mode
– OS comparator mode
– Tos = 80 °C
– Thyst = 75 °C
– OS output active state = LOW
– Pointer value = 0.
When the power supply voltage is dropped below the device
power-on reset level of about 1.9 V (POR) and then rises up again,
the device will be reset to its default condition as listed above.
Philips Semiconductors Product data sheet
SE95
Ultra high accuracy digital temperature sensor and
thermal Watchdog
2004 Dec 21 14
Data communication
The communication between the host and the SE95 must strictly
follow the rules as defined by the I2C-bus management. The
protocols for SE95 register read/write operations are illustrated by
the Figures as follows with these definitions:
1. Before a communication, the I2C-bus must be free or not busy. It
means that the SCL and SDA lines must be both released by all
devices on the bus, and they become HIGH by the bus pull-up
resistors.
2. The host must provide SCL clock pulses necessary for the
communication. Data is transferred in sequence of 9 SCL clock
pulses for every 8-bit data byte followed by 1-bit status of the
acknowledgement.
3. During data transfer, except the Start and Stop signals, the SDA
signal must be stable while the SCL signal is HIGH. It means
that SDA signal can be changed only during the LOW duration
of the SCL line.
4. S: Start signal, initiated by the host to start a communication,
the SDA goes from HIGH-to-LOW while the SCL is HIGH.
5. RS: Re-start signal, same as the Start signal, to start a read
command that follows a write command.
6. P: Stop signal, generated by the host to stop a communication,
the SDA goes from LOW-to-HIGH while the SCL is HIGH. The
bus becomes free thereafter.
7. W: Write bit, when the W rite/Read bit = LOW in a write
command.
8. R: Read bit, when the Write/Read bit = HIGH in a read
command.
9. A: Device Acknowledge bit, returned by the SE95. It is LOW if
the device works properly and HIGH if not. The host must
release the SDA line during this period in order to give the
device the control on the SDA line.
10.A′: Master Acknowledge bit, not returned by the device, but set
by the master or host in reading 2-byte data. During this clock
period, the host must set the SDA line to LOW in order to notice
the device that the first byte has been read for the device to
provide the second byte onto the bus.
11. NA: Not-Acknowledge bit. During this clock period, both the
device and host release the SDA line at the end of a data
transfer, the host is then enabled to generate the Stop signal.
12.In a write protocol, data is sent from the host to the device and
the host controls the SDA line, except during the clock period
when the device sends to the bus the device acknowledgement
signal.
13.In a read protocol, data is sent to the bus by the device and the
host must release the SDA line during the time that the device is
providing data onto the bus and controlling the SDA line, except
during the clock period when the master sends to the bus the
master acknowledgement signal.
Philips Semiconductors Product data sheet
SE95
Ultra high accuracy digital temperature sensor and
thermal Watchdog
2004 Dec 21 15
Protocols for writing and reading the registers
SL01393
123456789123456789123456789
1001A2A1A0 1WA 0000000S D4 D3 D2 D1A 000 A PD0
DEVICE ADDRESS POINTER BYTE
SCL
SDA
CONFIGURATION DATA BYTE
START WRITE DEVICE
ACKNOWLEDGE DEVICE
ACKNOWLEDGE
STOP
DEVICE
ACKNOWLEDGE
Figure 12. Write configuration register (1-byte data).
SL01398
123456789
1001A2A1A0 RA
DEVICE ADDRESS
SCL (cont.)
SDA (cont.)
READ DEVICE
ACKNOWLEDGE
D4 D3 D2 D1 D0D7 D6 D5
123456789
P
MASTER NOT
ACKNOWLEDGED
STOP
NA
DATA BYTE FROM DEVICE
123456789123456789
1001A2A1A0 1WA 0000000S A
DEVICE ADDRESS POINTER BYTE
SCL
SDA
START WRITE DEVICE
ACKNOWLEDGE DEVICE
ACKNOWLEDGE
0
RE-START
RS
(next)
(next)
Figure 13. Read configuration register including Pointer byte (1-byte data).
SL01394
123456789123456789
1001A2A1A0 RAS D4 D3 D2 D1 NA PD0
DEVICE ADDRESS
SCL
SDA
DATA BYTE FROM DEVICE
START READ DEVICE
ACKNOWLEDGE MASTER NOT
ACKNOWLEDGED
STOP
D7 D6 D5
Figure 14. Read configuration register with preset Pointer (1-byte data).
Philips Semiconductors Product data sheet
SE95
Ultra high accuracy digital temperature sensor and
thermal Watchdog
2004 Dec 21 16
SL01397
123456789123456789
D7 D6 D5 D4 D3 D2 D1 A D4 D3 D2 D1 AD0
SCL (cont.)
SDA (cont.)
LS BYTE DATA
DEVICE
ACKNOWLEDGE DEVICE
ACKNOWLEDGE
D7 D6 D5 P
STOP
123456789123456789
1001A2A1A0 P0WA 000000P1S A
DEVICE ADDRESS POINTER BYTE
SCL
SDA
START WRITE DEVICE
ACKNOWLEDGE DEVICE
ACKNOWLEDGE
(next)
(next)
D0
MS BYTE DATA
Figure 15. Write Tos or Thyst register (2-byte data).
SL01396
123456789123456789
1001A2A1A0 RA D4 D3 D2 D1 A′D0
DEVICE ADDRESS
SCL (cont.)
SDA (cont.)
MS BYTE FROM DEVICE
READ DEVICE
ACKNOWLEDGE MASTER
ACKNOWLEDGE
D7 D6 D5 D4 D3 D2 D1 D0D7 D6 D5
123456789
P
MASTER NOT
ACKNOWLEDGED
STOP
NA
LS BYTE FROM DEVICE
123456789123456789
1001A2A1A0 P0WA 000000P1S A
DEVICE ADDRESS POINTER BYTE
SCL
SDA
START WRITE DEVICE
ACKNOWLEDGE DEVICE
ACKNOWLEDGE
0
RE-START
RS
(next)
(next)
Figure 16. Read Temp or Tos or Thyst register including Pointer byte (2-byte data).
SL01395
123456789123456789
1001A2A1A0 RAS D4 D3 D2 D1 A′D0
DEVICE ADDRESS
SCL
SDA
MS BYTE FROM DEVICE
START READ DEVICE
ACKNOWLEDGE MASTER
ACKNOWLEDGE
D7 D6 D5 D4 D3 D2 D1 D0D7 D6 D5
123456789
P
MASTER NOT
ACKNOWLEDGED
STOP
NA
LS BYTE FROM DEVICE
Figure 17. Read Temp or Tos or Thyst register with preset Pointer (2-byte data).
Philips Semiconductors Product data sheet
SE95
Ultra high accuracy digital temperature sensor and
thermal Watchdog
2004 Dec 21 17
SO8: plastic small outline package; 8 leads; body width 3.9 mm SOT96-1
Philips Semiconductors Product data sheet
SE95
Ultra high accuracy digital temperature sensor and
thermal Watchdog
2004 Dec 21 18
TSSOP8: plastic thin shrink small outline package; 8 leads; body width 3 mm SOT505-1
Philips Semiconductors Product data sheet
SE95
Ultra high accuracy digital temperature sensor and
thermal Watchdog
2004 Dec 21 19
REVISION HISTOR Y
Rev Date Description
_3 20041221 Product data sheet (9397 750 14388). Supersedes data of 2004 Oct 05 (9397 750 14163).
Modifications:
•‘Features’ section on page 2,
–2nd bullet: add “(MSOP8)” as package name variant for TSSOP8
–3rd bullet: changed from “I2C-bus interface with up to 8 devices on the same bus” to “I2C-bus interface to
400 kHz with up to 8 devices on the same bus”
–8th bullet: changed from “... from 0 °C to +100 °C” to “... from –25 °C to +100 °C”
–12th bullet changed from “... 100 V MM per JESD22-A115” to “... 150 V MM per JESD22-A115”
•‘Absolute maximum ratings’ table on page 4: changed Vesd Machine Model (max.) from ‘100 V’ to ‘150 V’
•‘DC electrical characteristics’ table on page 5:
–Symbol TACC:
replaced “(assumes a minimum 11-bit temperature reading)” with “(Note 1)”
Conditions for VCC = 2.8 V to 3.6 V :
changed “Tamb = –25 °C to 100 °C” to “Tamb = –25 °C to +100 °C”
changed “Tamb = –55 °C to –125 °C” to “Tamb = –55 °C to +125 °C”
_2 20041005 Objective data sheet (9397 750 14163). Supersedes data of 2003 Oct 02 (9397 750 10265).
_1 20031002 Objective data (9397 750 10265)
Philips Semiconductors Product data sheet
SE95
Ultra high accuracy digital temperature sensor and
thermal Watchdog
2004 Dec 21 20
Purchase of Philips I2C components conveys a license under the Philips’ I2C patent
to use the components in the I2C system provided the system conforms to the
I2C specifications defined by Philips. This specification can be ordered using the
code 9398 393 40011.
Definitions
Short-form specification — The data in a short-form specification is extracted from a full data sheet with the same type number and title. For detailed information see
the relevant data sheet or data handbook.
Limiting values definition — Limiting values given are in accordance with the Absolute Maximum Rating System (IEC 60134). Stress above one or more of the limiting
values may cause permanent damage to the device. These are stress ratings only and operation of the device at these or at any other conditions above those given
in the Characteristics sections of the specification is not implied. Exposure to limiting values for extended periods may affect device reliability.
Application information — Applications that are described herein for any of these products are for illustrative purposes only. Philips Semiconductors make no
representation or warranty that such applications will be suitable for the specified use without further testing or modification.
Disclaimers
Life support — These products are not designed for use in life support appliances, devices, or systems where malfunction of these products can reasonably be
expected to result in personal injury. Philips Semiconductors customers using or selling these products for use in such applications do so at their own risk and agree
to fully indemnify Philips Semiconductors for any damages resulting from such application.
Right to make changes — Philips Semiconductors reserves the right to make changes in the products—including circuits, standard cells, and/or software—described
or contained herein in order to improve design and/or performance. When the product is in full production (status ‘Production’), relevant changes will be communicated
via a Customer Product/Process Change Notification (CPCN). Philips Semiconductors assumes no responsibility or liability for the use of any of these products, conveys
no license or title under any patent, copyright, or mask work right to these products, and makes no representations or warranties that these products are free from patent,
copyright, or mask work right infringement, unless otherwise specified.
Contact information
For additional information please visit
http://www.semiconductors.philips.com. Fax: +31 40 27 24825
For sales offices addresses send e-mail to:
sales.addresses@www.semiconductors.philips.com.
Koninklijke Philips Electronics N.V. 2004
All rights reserved. Published in the U.S.A.
Date of release: 12-04
Document number: 9397 750 14388
Data sheet status[1]
Objective data
Preliminary data
Product data
Product
status[2] [3]
Development
Qualification
Production
Definitions
This data sheet contains data from the objective specification for product development.
Philips Semiconductors reserves the right to change the specification in any manner without notice.
This data sheet contains data from the preliminary specification. Supplementary data will be published
at a later date. Philips Semiconductors reserves the right to change the specification without notice, in
order to improve the design and supply the best possible product.
This data sheet contains data from the product specification. Philips Semiconductors reserves the
right to make changes at any time in order to improve the design, manufacturing and supply. Relevant
changes will be communicated via a Customer Product/Process Change Notification (CPCN).
Data sheet status
[1] Please consult the most recently issued data sheet before initiating or completing a design.
[2] The product status of the device(s) described in this data sheet may have changed since this data sheet was published. The latest information is available on the Internet at URL
http://www.semiconductors.philips.com.
[3] For data sheets describing multiple type numbers, the highest-level product status determines the data sheet status.
Level
I
II
III
