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LM75B

Digital temperature sensor and thermal watchdog

Rev. 02 — 9 December 2008

Product data sheet

1. General description

The LM75B is a temperature-to-digital converter using an on-chip band gap temperature

sensor and Sigma-Delta A-to-D conversion technique with an overtemperature detection

output. The LM75B contains a number of data registers: Conﬁguration register (Conf) to

store the device settings such as device operation mode, OS operation mode, OS polarity

and OS fault queue as described in Section 7 “Functional description”; temperature

register (Temp) to store the digital temp reading, and set-point registers (Tos and Thyst) to

store programmable overtemperature shutdown and hysteresis limits, that can be

communicated by a controller via the 2-wire serial I²C-bus interface. The device also

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 LM75B 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 or 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 an 11-bit 2's complement data giving a

temperature resolution of 0.125 °C. This high temperature resolution is particularly useful

in applications of measuring precisely the thermal drift or runaway. When the LM75B is

accessed the conversion in process is not interrupted (i.e., the I²C-bus section is totally

independent of the Sigma-Delta converter section) and accessing the LM75B

continuously without waiting at least one conversion time between communications will

not prevent the device from updating the Temp register with a new conversion result. The

new conversion result will be available immediately after the Temp register is updated.

The LM75B powers up in the 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.

2. Features

I Pin-for-pin replacement for industry standard LM75 and LM75A and offers improved

temperature resolution of 0.125 °C and speciﬁcation of a single part over power supply

range from 2.8 V to 5.5 V

I I²C-bus interface with up to 8 devices on the same bus

I Power supply range from 2.8 V to 5.5 V

I Temperatures range from −55 °C to +125 °C

LM75B

NXP Semiconductors

Digital temperature sensor and thermal watchdog

I Frequency range 20 Hz to 400 kHz with bus fault time-out to prevent hanging up the

bus

I 11-bit ADC that offers a temperature resolution of 0.125 °C

I Temperature accuracy of:

N ±2 °C from −25 °C to +100 °C

N ±3 °C from −55 °C to +125 °C

I Programmable temperature threshold and hysteresis set points

I Supply current of 1.0 µA in shutdown mode for power conservation

I Stand-alone operation as thermostat at power-up

I ESD protection exceeds 4500 V HBM per JESD22-A114, 450 V MM per

JESD22-A115 and 2000 V CDM per JESD22-C101

I Latch-up testing is done to JEDEC Standard JESD78 which exceeds 100 mA

I Small 8-pin package types: SO8, TSSOP8 and 3 mm × 2 mm XSON8U

3. Applications

I System thermal management

I Personal computers

I Electronics equipment

I Industrial controllers

4. Ordering information

Table 1.

Ordering information

Type

Topside Package

number

mark

Name

Description

Version

LM75BD

LM75BD SO8

plastic small outline package; 8 leads; body width 3.9 mm

SOT96-1

SOT505-1

SOT996-2

LM75BDP

LM75BGD

LM75B

75B

TSSOP8 plastic thin shrink small outline package; 8 leads; body width 3 mm

XSON8U plastic extremely thin small outline package; no leads; 8 terminals;

UTLP based; body 3 × 2 × 0.5 mm

LM75B_2

Product data sheet

Rev. 02 — 9 December 2008

2 of 29

LM75B

NXP Semiconductors

Digital temperature sensor and thermal watchdog

5. Block diagram

V

CC

LM75B

BIAS

REFERENCE

POINTER

REGISTER

CONFIGURATION

REGISTER

TEMPERATURE

REGISTER

COUNTER

TIMER

BAND GAP

TEMP SENSOR

11-BIT

SIGMA-DELTA

A-to-D

TOS

REGISTER

CONVERTER

OSCILLATOR

COMPARATOR/

INTERRUPT

THYST

REGISTER

POWER-ON

RESET

OS

LOGIC CONTROL AND INTERFACE

002aad453

A2 A1 A0

SCL SDA

GND

Fig 1. Block diagram of LM75B

6. Pinning information

6.1 Pinning

1

2

3

4

8

7

6

5

SDA

SCL

OS

V

CC

1

2

3

4

8

7

6

5

SDA

SCL

OS

V

CC

A0

A1

A2

A0

A1

A2

LM75BD

LM75BDP

GND

002aad455

002aad454

Fig 2. Pin conﬁguration for SO8

Fig 3. Pin conﬁguration for TSSOP8

SDA

SCL

OS

1

2

3

4

8

7

6

5

V

CC

A0

A1

A2

LM75BGD

GND

002aae234

Transparent top view

Fig 4. Pin conﬁguration for XSON8U

LM75B_2

Product data sheet

Rev. 02 — 9 December 2008

3 of 29

LM75B

NXP Semiconductors

Digital temperature sensor and thermal watchdog

6.2 Pin description

Table 2.

Symbol

SDA

SCL

OS

Pin description

1

Description

Digital I/O. I²C-bus serial bidirectional data line; open-drain.

Digital input. I²C-bus serial clock input.

Overtemp Shutdown output; open-drain.

Ground. To be connected to the system ground.

Digital input. User-deﬁned address bit 2.

Digital input. User-deﬁned address bit 1.

Digital input. User-deﬁned address bit 0.

Power supply.

2

3

GND

A2

4

5

A1

6

A0

7

V_CC

8

7. Functional description

7.1 General operation

The LM75B uses the on-chip band gap sensor to measure the device temperature with

the resolution of 0.125 °C and stores the 11-bit 2's complement digital data, resulted from

11-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 shutdown. In normal operation

mode, the temp-to-digital conversion is executed every 100 ms and the Temp register is

updated at the end of each conversion. During each ‘conversion period’ (T_conv) of about

100 ms the device takes only about 10 ms, called ‘temperature conversion time’ (t_conv(T)),

to complete a temperature-to-data conversion and then becomes idle for the time

remaining in the period. This feature is implemented to signiﬁcantly reduce the device

power dissipation. In shutdown mode, the device becomes idle, data conversion is

disabled and the Temp register holds the latest result; however, the device I²C-bus

interface is still active and register write/read operation can be performed. The device

operation mode is controllable by programming bit B0 of the conﬁguration register. The

temperature conversion is initiated when the device is powered-up or put back into normal

mode from shutdown.

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 overtemperature shutdown

threshold data (or T_th(ots)) stored in the Tos register, and the hysteresis data (or T_hys

)

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 11-bit data for the comparison.

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.

LM75B_2

Product data sheet

Rev. 02 — 9 December 2008

4 of 29

LM75B

NXP Semiconductors

Digital temperature sensor and thermal watchdog

In OS comparator mode, the OS output behaves like a thermostat. It becomes active

when the Temp exceeds the T_th(ots), and is reset when the Temp drops below the T_hys

.

Reading the device registers or putting the device into shutdown 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 T_th(ots); then

it remains active indeﬁnitely until being reset by a read of any register. Once the OS output

has been activated by crossing T_th(ots)and then reset, it can be activated again only when

the Temp drops below the T_hys; 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:

T_th(ots)trip, Reset, T_hystrip, Reset, T_th(ots)trip, Reset, T_hystrip, Reset, etc. Putting the

device into the shutdown mode by setting the bit 0 of the conﬁguration register 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 T_th(ots)is set to 80 °C, the

T_hysis 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

100 ms.

The OS response to the temperature is illustrated in Figure 5.

T

th(ots)

T

hys

reading temperature limits

OS reset

OS active

OS output in comparator mode

OS reset

OS active

(1)

OS output in interrupt mode

002aae334

(1) OS is reset by either reading register or putting the device in shutdown mode. It is assumed that

the fault queue is met at each T_th(ots)and T_hyscrossing point.

Fig 5. OS response to temperature

LM75B_2

Product data sheet

Rev. 02 — 9 December 2008

5 of 29

LM75B

NXP Semiconductors

Digital temperature sensor and thermal watchdog

7.2 I²C-bus serial interface

The LM75B 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. Notice that if the I²C-bus 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 Section 7.10.

7.2.1 Bus fault time-out

If the SDA line is held LOW for longer than t_to(75 ms minimum / 13.3 Hz; guaranteed at

50 ms minimum / 20 Hz), the LM75B will reset to the idle state (SDA released) and wait

for a new START condition. This ensures that the LM75B will never hang up the bus

should there be conﬂict in the transmission sequence.

7.3 Slave address

The LM75B slave address on the I²C-bus is partially deﬁned by the logic applied to the

device address pins A2, A1 and A0. Each of them is typically connected either to GND for

logic 0, or to V_CCfor 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 LM75B. Table 3 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 and A2 to A0, are not internally biased, it is important that they should not

be left ﬂoating in any application.

Table 3.

Address table

1 = HIGH; 0 = LOW.

MSB

LSB

1

0

1

A2

A1

A0

7.4 Register list

The LM75B contains four data registers beside the pointer register as listed in Table 4.

The pointer value, read/write capability and default content at power-up of the registers

are also shown in Table 4.

Table 4.

Register table

Register Pointer R/W

POR

state

Description

name

value

Conf

01h

R/W

00h

Conﬁguration register: contains a single 8-bit data

byte; to set the device operating condition; default = 0.

Temp

Tos

00h

03h

read only n/a

Temperature register: contains two 8-bit data bytes;

to store the measured Temp data.

R/W

5000h

Overtemperature shutdown threshold register:

contains two 8-bit data bytes; to store the

overtemperature shutdown T_th(ots)limit;

default = 80 °C.

Thyst

02h

R/W

4B00h

Hysteresis register: contains two 8-bit data bytes;

to store the hysteresis T_hyslimit; default = 75 °C.

LM75B_2

Product data sheet

Rev. 02 — 9 December 2008

6 of 29

LM75B

NXP Semiconductors

Digital temperature sensor and thermal watchdog

7.4.1 Pointer register

The Pointer register contains an 8-bit data byte, of which the two LSB bits represent the

pointer value of the other four registers, and the other 6 MSB bits are equal to 0, as shown

in Table 5 and Table 6. The Pointer register is not accessible to the user, but is used to

select the data register for write/read operation by including the pointer data byte in the

bus command.

Table 5.

Pointer register

B7

B6

B5

B4

B3

B2

B[1:0]

0

pointer value

Table 6.

Pointer value

B1

0

B0

0

Selected register

Temperature register (Temp)

Conﬁguration register (Conf)

Hysteresis register (Thyst)

0

1

0

1

Overtemperature shutdown register (Tos)

Because the Pointer value is latched into the Pointer register when the bus command

(which includes the pointer byte) is executed, a read from the LM75B may or may not

include the pointer byte in the statement. To read again a register that has been recently

read and the pointer has been preset, the pointer byte does not have to be included. To

read a register that is different from the one that has been recently read, the pointer byte

must be included. However, a write to the LM75B must always include the pointer byte in

the statement. The bus communication protocols are described in Section 7.10.

At power-up, the Pointer value is equal to 00 and the Temp register is selected; users can

then read the Temp data without specifying the pointer byte.

7.4.2 Conﬁguration register

The Conﬁguration register (Conf) is a write/read register and contains an 8-bit

non-complement data byte that is used to conﬁgure the device for different operation

conditions. Table 7 shows the bit assignments of this register.

Table 7.

Conf register

Legend: * = default value.

Bit Symbol

B[7:5] reserved

Access Value Description

R/W 000* reserved for manufacturer’s use; should be kept as

zeroes for normal operation

OS fault queue programming

queue value = 1

B[4:3] OS_F_QUE[1:0] R/W

00*

01

10

11

queue value = 2

queue value = 4

queue value = 6

B2

OS_POL

R/W

OS polarity selection

OS active LOW

0*

1

OS active HIGH

LM75B_2

Product data sheet

Rev. 02 — 9 December 2008

7 of 29

LM75B

NXP Semiconductors

Digital temperature sensor and thermal watchdog

Table 7.

Conf register …continued

Legend: * = default value.

Bit

Symbol

Access Value Description

B1

OS_COMP_INT R/W

OS operation mode selection

OS comparator

0*

1

OS interrupt

B0

SHUTDOWN

R/W

device operation mode selection

normal

0*

1

shutdown

7.4.3 Temperature register

The Temperature register (Temp) holds the digital result of temperature measurement or

monitor at the end of each analog-to-digital conversion. This register is read-only and

contains two 8-bit data bytes consisting of one Most Signiﬁcant Byte (MSByte) and one

Least Signiﬁcant Byte (LSByte). However, only 11 bits of those two bytes are used to store

the Temp data in 2’s complement format with the resolution of 0.125 °C. Table 8 shows the

bit arrangement of the Temp data in the data bytes.

Table 8.

MSByte

Temp register

LSByte

7

6

5

4

3

2

1

0

7

6

5

4

3

2

1

0

D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0

X

When reading register Temp, all 16 bits of the two data bytes (MSByte and LSByte) are

provided to the bus and must be all collected by the controller to complete the bus

operation. However, only the 11 most signiﬁcant bits should be used, and the 5 least

signiﬁcant bits of the LSByte are zero and should be ignored. One of the ways to calculate

the Temp value in °C from the 11-bit Temp data is:

1. If the Temp data MSByte bit D10 = 0, then the temperature is positive and Temp value

(°C) = +(Temp data) × 0.125 °C.

2. If the Temp data MSByte bit D10 = 1, then the temperature is negative and

Temp value (°C) = −(2’s complement of Temp data) × 0.125 °C.

Examples of the Temp data and value are shown in Table 9.

Table 9.

Temp register value

11-bit binary

Hexadecimal value

Decimal value

Value

(2’s complement)

011 1111 1000

011 1111 0111

011 1111 0001

011 1110 1000

000 1100 1000

000 0000 0001

000 0000 0000

111 1111 1111

3F8

3F7

3F1

3E8

0C8

001

000

7FF

1016

1015

1009

1000

200

1

+127.000 °C

+126.875 °C

+126.125 °C

+125.000 °C

+25.000 °C

+0.125 °C

0

0.000 °C

−1

−0.125 °C

LM75B_2

Product data sheet

Rev. 02 — 9 December 2008

8 of 29

LM75B

NXP Semiconductors

Digital temperature sensor and thermal watchdog

Table 9.

Temp register value …continued

11-bit binary

Hexadecimal value

Decimal value

Value

(2’s complement)

111 0011 1000

110 0100 1001

110 0100 1000

738

649

648

−200

−439

−440

−25.000 °C

−54.875 °C

−55.000 °C

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 of the LSByte. The 9-bit Temp data with

0.5 °C resolution of the LM75B is deﬁned exactly in the same way as for the standard

LM75 and it is here similar to the Tos and Thyst registers.

The only MSByte of the temperature can also be read with the use of a one-byte reading

command. Then the temperature resolution will be 1.00 °C instead.

7.4.4 Overtemperature shutdown 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 overtemperature shutdown

threshold (T_th(ots)) and hysteresis temperature (T_hys), 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; see Section 7.1.

Each of the set-point registers contains two 8-bit data bytes consisting of one MSByte and

one LSByte the same as register Temp. 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. Table 10

and Table 11 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 of the Temp data for data comparison.

Table 10. Tos register

MSByte

LSByte

7

6

5

4

3

2

1

0

7

6

5

4

3

2

1

0

D8 D7 D6 D5 D4 D3 D2 D1 D0

X

Table 11. Thyst register

MSByte

LSByte

7

6

5

4

3

2

1

0

7

6

5

4

3

2

1

0

D8 D7 D6 D5 D4 D3 D2 D1 D0

X

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 most signiﬁcant bits

should be used and the 7 LSB of the LSByte are equal to zero and should be ignored.

Table 12 shows examples of the limit data and value.

LM75B_2

Product data sheet

Rev. 02 — 9 December 2008

9 of 29

LM75B

NXP Semiconductors

Digital temperature sensor and thermal watchdog

Table 12. Tos and Thyst limit data and value

11-bit binary

Hexadecimal value

Decimal value

Value

(2’s complement)

0 1111 1010

0 0011 0010

0 0000 0001

0 0000 0000

1 1111 1111

1 1100 1110

1 1001 0010

0FA

032

001

000

1FF

1CE

192

250

50

+125.0 °C

+25.0 °C

+0.5 °C

0.0 °C

1

0

−1

−0.5 °C

−50

−110

−25.0 °C

−55.0 °C

7.5 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 Section 7.1. In order to observe this output state, an

external pull-up resistor is needed. The resistor should be as large as possible, up to

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

(OS_POL) of register Conf: setting bit OS_POL to logic 1 selects OS active HIGH and

setting bit B2 to logic 0 sets OS active LOW. At power-up, bit OS_POL is equal to logic 0

and the OS active state is LOW.

7.6 OS comparator and interrupt modes

As described in Section 7.1, the device OS output responds to the result of the

comparison between register Temp data and the programmed limits, in registers 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 (OS_COMP_INT) of

register Conf: setting bit OS_COMP_INT to logic 1 selects the OS interrupt mode, and

setting to logic 0 selects the OS comparator mode. At power-up, bit OS_COMP_INT is

equal to logic 0 and the OS comparator is selected.

The main difference between the two modes is that in OS comparator mode, the OS

output becomes active when Temp has exceeded T_th(ots)and reset when Temp has

dropped below T_hys, reading a register or putting the device into shutdown mode does not

change the state of the OS output; while in OS interrupt mode, once it has been activated

either by exceeding T_th(ots)or dropping below T_hys, the OS output will remain active

indeﬁnitely until reading a register, then the OS output is reset.

Temperature limits T_th(ots)and T_hysmust be selected so that T_th(ots)> T_hys. Otherwise, the

OS output state will be undeﬁned.

LM75B_2

Product data sheet

Rev. 02 — 9 December 2008

10 of 29

LM75B

NXP Semiconductors

Digital temperature sensor and thermal watchdog

7.7 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 (OS_F_QUE[1:0]) in register Conf.

Notice that the programmed data and the fault queue value are not the same. Table 13

shows the one-to-one relationship between them. At power-up, fault queue data = 0 and

fault queue value = 1.

Table 13. Fault queue table

Fault queue data

Fault queue value

OS_F_QUE[1]

OS_F_QUE[0]

Decimal

0

1

0

1

0

1

2

4

6

7.8 Shutdown mode

The device operation mode is selected by programming bit B0 (SHUTDOWN) of register

Conf. Setting bit SHUTDOWN to logic 1 will put the device into shutdown mode. Resetting

bit SHUTDOWN to logic 0 will return the device to normal mode.

In shutdown mode, the device draws a small current of approximately 1.0 µA and the

power dissipation is minimized; the temperature conversion stops, but the I²C-bus

interface remains active and register write/read operation can be performed. When the

shutdown is set, the OS output will be unchanged in comparator mode and reset in

interrupt mode.

7.9 Power-up default and power-on reset

The LM75B always powers-up in its default state with:

• Normal operation mode

• OS comparator mode

• T_th(ots)= 80 °C

• T_hys= 75 °C

• OS output active state is LOW

• Pointer value is logic 00 (Temp)

When the power supply voltage is dropped below the device power-on reset level of

approximately 1.0 V (POR) for over 2 µs and then rises up again, the device will be reset

to its default condition as listed above.

LM75B_2

Product data sheet

Rev. 02 — 9 December 2008

11 of 29

LM75B

NXP Semiconductors

Digital temperature sensor and thermal watchdog

7.10 Protocols for writing and reading the registers

The communication between the host and the LM75B must strictly follow the rules as

deﬁned by the I²C-bus management. The protocols for LM75B register read/write

operations are illustrated in Figure 6 to Figure 11 together with the following deﬁnitions:

1. Before a communication, the I²C-bus must be free or not busy. It means that the SCL

and SDA lines must both be 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 a 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 the 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 write/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 LM75B. 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 notify 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 the device

acknowledgement signal to the bus.

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 the master

acknowledgement signal to the bus.

LM75B_2

Product data sheet

Rev. 02 — 9 December 2008

12 of 29

LM75B

NXP Semiconductors

Digital temperature sensor and thermal watchdog

1

2

0

3

0

4

1

5

6

7

8

9

1

0

2

0

3

0

4

0

5

0

6

0

7

0

8

1

9

1

0

2

0

3

0

4

5

6

7

8

9

SCL

SDA

S

A2 A1 A0 W

A

D4 D3 D2 D1 D0

A

P

device address

START

pointer byte

configuration data byte

device

write

device

acknowledge

device

acknowledge

STOP

acknowledge

001aad624

Fig 6. Write conﬁguration register (1-byte data)

1

2

0

3

0

4

1

5

6

7

8

9

1

0

2

0

3

0

4

0

5

6

0

7

0

8

1

9

(next)

SCL

SDA

0

A

RS (next)

S

A2 A1 A0

W

A

device address

pointer byte

START

device

acknowledge

RE-START

write

device

acknowledge

1

2

3

0

4

1

5

6

7

8

9

1

2

3

4

5

6

7

8

9

SCL (cont.)

SDA (cont.)

0

A2 A1 A0

R

A

D7 D6 D5 D4 D3 D2 D1 D0 NA

data byte from device

P

device address

master not

STOP

read

acknowledged

device

acknowledge

001aad625

Fig 7. Read conﬁguration register including pointer byte (1-byte data)

1

2

0

3

0

4

1

5

6

7

8

9

1

2

3

4

5

6

7

8

9

SCL

SDA

A2 A1 A0

R

A

D7 D6 D5 D4 D3 D2 D1 D0 NA

data byte from device

P

S

device address

START

master not

STOP

read

acknowledged

device

acknowledge

001aad626

Fig 8. Read conﬁguration or temp register with preset pointer (1-byte data)

LM75B_2

Product data sheet

Rev. 02 — 9 December 2008

13 of 29

LM75B

NXP Semiconductors

Digital temperature sensor and thermal watchdog

1

2

0

3

0

4

1

5

6

7

8

9

1

0

2

0

3

0

4

0

5

0

6

0

7

8

9

SCL

(next)

SDA

S

A2 A1 A0

W

A

P1 P0

A

device address

pointer byte

START

device

acknowledge

write

device

acknowledge

1

2

3

4

5

6

7

8

9

1

2

3

4

5

6

7

8

9

SCL (cont.)

SDA (cont.)

D7 D6 D5 D4 D3 D2 D1 D0

MSByte data

A

D7 D6 D5 D4 D3 D2 D1 D0

LSByte data

A

P

device

STOP

acknowledge

device

acknowledge

002aad036

Fig 9. Write Tos or Thyst register (2-byte data)

1

2

0

3

0

4

1

5

6

7

8

9

1

0

2

0

3

0

4

0

5

0

6

0

7

8

9

0

SCL

SDA

(next)

S

A2 A1 A0 W

A

P1 P0

device

A

RS (next)

device address

START

pointer byte

RE-START

write

device

acknowledge

1

2

0

3

0

4

1

5

6

7

8

9

1

2

3

4

5

6

7

8

9

1

2

3

4

5

6

7

8

9

SCL (cont)

SDA (cont)

A2 A1 A0

R

A

D7 D6 D5 D4 D3 D2 D1 D0 A' D7 D6 D5 D4 D3 D2 D1 D0 NA

P

device address

MSByte from device

master

LSByte from device

master not

read

device

acknowledge

STOP

acknowledge

acknowledged

002aad037

Fig 10. Read Temp, Tos or Thyst register including pointer byte (2-byte data)

1

2

0

3

0

4

1

5

6

7

8

9

1

2

3

4

5

6

7

8

9

1

2

3

4

5

6

7

8

9

SCL

SDA

S

A2 A1 A0

R

A

D7 D6 D5 D4 D3 D2 D1 D0 A' D7 D6 D5 D4 D3 D2 D1 D0 NA

P

device address

START

MSByte from device

master

LSByte from device

master not

read

device

acknowledge

STOP

acknowledge

acknowledged

002aad038

Fig 11. Read Temp, Tos or Thyst register with preset pointer (2-byte data)

LM75B_2

Product data sheet

Rev. 02 — 9 December 2008

14 of 29

LM75B

NXP Semiconductors

Digital temperature sensor and thermal watchdog

8. Application design-in information

8.1 Typical application

power supply

0.1 µF

BUS

PULL-UP

RESISTORS

10 kΩ

V

CC

8

SCL

SDA

2

1

2

I C-BUS

OS

DETECTOR OR

INTERRUPT LINE

3

LM75B

A2

A1

A0

5

6

7

DIGITAL LOGIC

4

GND

002aad457

Fig 12. Typical application

8.2 LM75A and LM75B comparison

Table 14. LM75A and LM75B comparison

Description

LM75A

no

LM75B

yes

availability of the XSON8U (3 mm × 2 mm) package type

OS output auto-reset when SHUTDOWN bit is set in interrupt mode^[1]

support single-byte reading of the Temp registers without bus lockup^[2]

no

yes

no

yes

bus fault time-out (75 ms, 200 ms)^[3]

no

yes

[4]

minimum data hold time (t_HD;DAT

)

10 ns

0 ns

ratio of conversion time / conversion period (typical)^[5]

supply current in shutdown mode (typical value)

HBM ESD protection level (minimum)

100 ms / 100 ms

3.5 µA

>2000 V

>200 V

>1000 V

10 ms / 100 ms

0.2 µA

>4500 V

>450 V

>2000 V

MM ESD protection level (minimum)

CDM ESD protection level (minimum)

[1] This option is updated to be compatible with the competitive parts. When the OS output has been activated in the interrupt mode due to

a temp limit violation, if the Conﬁguration Shutdown bit B0 is set (to the LM75A), then the OS output activated status remains

unchanged, while (to the LM75B) the OS will be reset. The latter is compatible with the operation condition of the competitive parts.

[2] The LM75 series is intentionally designed to provide two successive temperature data bytes (MSByte and LSByte) for the 11-bit data

resolution and both bytes should be read in a typical application. In some speciﬁc applications, when only the MSByte is read using a

single-byte read command, it often happens that if bit D7 of the LSByte is zero, then the device will hold the SDA bus in a LOW state

forever, resulting in a bus hang-up problem, and the bus cannot be released until the device power is reset. This condition exists for the

LM75A but not for the LM75B. For the LM75B the temperature can be read either one byte or two bytes without a hang-up problem.

[3] The bus time-out is included for releasing the LM75B device operation whenever the SDA input is kept at a LOW state for too long

(longer than the LM75B time-out duration) due to a fault from the host. The trade-off for this option is the limitation of the I²C-bus low

frequency operation to be limited to 20 Hz. This option is compatible with some of the latest versions of the competitive parts.

[4] The data hold time is improved to increase the timing margin in I²C-bus operation.

LM75B_2

Product data sheet

Rev. 02 — 9 December 2008

15 of 29

LM75B

NXP Semiconductors

Digital temperature sensor and thermal watchdog

[5] The LM75B performs the temperature-to-data conversions with a much higher speed than the LM75A. While the LM75A takes almost

the whole of conversion period (T_conv) time of about 100 ms to complete a conversion, the LM75B takes only about ¹⁄₁₀of the period, or

about 10 ms. Therefore, the conversion period (T_conv) is the same, but the temperature conversion time (t_conv(T)) is different between the

two parts. A shorter conversion time is applied to signiﬁcantly reduce the device’s average power dissipation. During each conversion

period, when the conversion is completed, the LM75B becomes idled and the power is reduced, resulting in a lesser average power

consumption.

8.3 Temperature accuracy

Because the local channel of the temperature sensor measures its own die temperature

that is transferred from its body, the temperature of the device body must be stabilized and

saturated for it to provide the stable readings. Because the LM75B operates a a low power

level, the thermal gradient of the device package has a minor effect on the measurement.

The accuracy of the measurement is more dependent upon the deﬁnition of the

environment temperature, which is affected by different factors: the printed-circuit board

on which the device is mounted; the air ﬂow contacting the device body (if the ambient air

temperature and the printed-circuit board temperature are much different, then the

measurement may not be stable because of the different thermal paths between the die

and the environment). The stabilized temperature liquid of a thermal bath will provide the

best temperature environment when the device is completely dipped into it. A thermal

probe with the device mounted inside a sealed-end metal tube located in consistent

temperature air also provides a good method of temperature measurement.

8.4 Noise effect

The LM75B device design includes the implementation of basic features for a good noise

immunity:

• The low-pass ﬁlter on both the bus pins SCL and SDA;

• The hysteresis of the threshold voltages to the bus input signals SCL and SDA, about

500 mV minimum;

• All pins have ESD protection circuitry to prevent damage during electrical surges. The

ESD protection on the address, OS, SCL and SDA pins it to ground. The latch-back

based device breakdown voltage of address/OS is typically 11 V and SCL/SDA is

typically 9.5 V at any supply voltage but will vary over process and temperature. Since

there are no protection diodes from SCL or SDA to V_CC, the LM75B will not hold the

I²C lines LOW when V_CCis not supplied and therefore allow continued I²C-bus

operation if the LM75B is de-powered.

However, good layout practices and extra noise ﬁlters are recommended when the device

is used in a very noisy environment:

• Use decoupling capacitors at V_CCpin.

• Keep the digital traces away from switching power supplies.

• Apply proper terminations for the long board traces.

• Add capacitors to the SCL and SDA lines to increase the low-pass ﬁlter

characteristics.

LM75B_2

Product data sheet

Rev. 02 — 9 December 2008

16 of 29

LM75B

NXP Semiconductors

Digital temperature sensor and thermal watchdog

9. Limiting values

Table 15. Limiting values

In accordance with the Absolute Maximum Rating System (IEC 60134).

Symbol Parameter

Conditions

Min

−0.3

−5.0

-

Max

+6.0

+5.0

10.0

+6.0

+150

150

Unit

V

V_CC

V_I

supply voltage

input voltage

at input pins

on pin OS

V

I_I

input current

mA

V

I_O(sink)

V_O

T_stg

T_j

output sink current

output voltage

on pin OS

−0.3

−65

-

storage temperature

junction temperature

°C

10. Recommended operating conditions

Table 16. Recommended operating characteristics

Symbol Parameter Conditions

Min

2.8

Typ

Max

Unit

V

V_CC

supply voltage

-

5.5

T_amb

ambient temperature

−55

+125

°C

LM75B_2

Product data sheet

Rev. 02 — 9 December 2008

17 of 29

LM75B

NXP Semiconductors

Digital temperature sensor and thermal watchdog

11. Static characteristics

Table 17. Static characteristics

V_CC= 2.8 V to 5.5 V; T_amb= −55 °C to +125 °C; unless otherwise speciﬁed.

Symbol

Parameter

Conditions

Min

−2

−3

-

Typ^[1]

Max

+2

+3

-

Unit

°C

T_acc

temperature accuracy

T_amb= −25 °C to +100 °C

T_amb= −55 °C to +125 °C

11-bit digital temp data

normal mode

-

°C

T_res

temperature resolution

0.125

10

°C

t_conv(T)

temperature conversion

time

-

ms

T_conv

conversion period

normal mode

-

100

-

ms

µA

I_DD(AV)

average supply current

normal mode: I²C-bus inactive

normal mode: I²C-bus active;

200

300

f

_SCL= 400 kHz

shutdown mode

HIGH-level input voltage digital pins (SCL, SDA, A2 to A0)

LOW-level input voltage digital pins

-

0.2

1.0

µA

V

V_IH

0.7 × V_CC

-

V_CC+ 0.3

V_IL

−0.3

-

0.3 × V_CC

V

V_I(hys)

hysteresis of input voltage SCL and SDA pins

A2, A1, A0 pins

-

300

-

mV

mv

µA

V

-

150

-

I_IH

HIGH-level input current

LOW-level input current

digital pins; V_I= V_CC

digital pins; V_I= 0 V

−1.0

-

+1.0

0.4

0.8

10

6

I_IL

−1.0

V_OL

LOW-level output voltage SDA and OS pins; I_OL= 3 mA

I_OL= 4 mA

-

V

I_LO

output leakage current

number of faults

SDA and OS pins; V_OH= V_CC

-

µA

N_fault

programmable; conversions in

overtemperature-shutdown fault

queue

1

T_th(ots)

overtemperature

shutdown threshold

temperature

default value

-

80

-

°C

T_hys

C_i

hysteresis temperature

input capacitance

default value

digital pins

-

75

20

-

°C

pF

[1] Typical values are at V_CC= 3.3 V and T_amb= 25 °C.

LM75B_2

Product data sheet

Rev. 02 — 9 December 2008

18 of 29

LM75B

NXP Semiconductors

Digital temperature sensor and thermal watchdog

002aae198

002aae199

300

V

= 5.5 V

4.5 V

3.3 V

2.8 V

CC

I

DD(AV)

(µA)

DD(AV)

(µA)

V

= 5.5 V

4.5 V

3.3 V

2.8 V

CC

200

100

0

200

100

0

−75

−25

25

75

125

(°C)

−75

−25

25

75

125

(°C)

T

amb

Fig 13. Average supply current versus temperature;

I²C-bus inactive

Fig 14. Average supply current versus temperature;

I²C-bus active

002aae200

002aae201

0.5

I

V

DD(sd)

(µA)

OL(OS)

(V)

0.4

V

= 5.5 V

4.5 V

3.3 V

2.8 V

CC

V

= 5.5 V

4.5 V

3.3 V

2.8 V

CC

0.3

0.2

0.1

0

0.3

0.2

0.1

0

−75

−25

25

75

125

(°C)

−75

−25

25

75

125

(°C)

T

amb

Fig 15. Shutdown mode supply current

versus temperature

Fig 16. LOW-level output voltage on pin OS

versus temperature; I_OL= 4 mA

002aae202

002aae203

0.5

2.0

V

OL(SDA)

T

(°C)

acc

(V)

0.4

0.3

0.2

0.1

0

V

= 5.5 V

4.5 V

3.3 V

2.8 V

CC

1.0

0

−1.0

−2.0

−75

−25

25

75

125

(°C)

−75

−25

25

75

125

(°C)

T

amb

Fig 17. LOW-level output voltage on pin SDA

versus temperature; I_OL= 4 mA

Fig 18. Typical temperature accuracy versus

temperature; V_CC= 3.3 V

LM75B_2

Product data sheet

Rev. 02 — 9 December 2008

19 of 29

LM75B

NXP Semiconductors

Digital temperature sensor and thermal watchdog

12. Dynamic characteristics

Table 18. I²C-bus interface dynamic characteristics^[1]

V_CC= 2.8 V to 5.5 V; T_amb= −55 °C to +125 °C; unless otherwise speciﬁed.

Symbol

f_SCL

Parameter

Conditions

Min

0.02

0.6

1.3

100

0

Typ

Max

Unit

kHz

µs

SCL clock frequency

HIGH period of the SCL clock

LOW period of the SCL clock

hold time (repeated) START condition

data set-up time

see Figure 19

-

400

t_HIGH

-

t_LOW

-

µs

t_HD;STA

t_SU;DAT

t_HD;DAT

t_SU;STO

t_f

-

ns

-

ns

data hold time

-

ns

set-up time for STOP condition

fall time

100

-

ns

SDA and OS outputs;

250

ns

C_L= 400 pF; I_OL= 3 mA

[2][3]

t_to

time-out time

75

-

200

ms

[1] These speciﬁcations are guaranteed by design and not tested in production.

[2] This is the SDA time LOW for reset of serial interface.

[3] Holding the SDA line LOW for a time grater than t_towill cause the LM75B to reset SDA to the idle state of the serial bus communication

(SDA set HIGH).

SDA

t

BUF

t

LOW

t

SP

SU;DAT

HD;STA

t

f

t

r

t

r

t

f

SCL

t

SU;STO

HD;STA

SU;STA

t

HIGH

S

Sr

P

S

t

HD;DAT

002aab271

Fig 19. Timing diagram

LM75B_2

Product data sheet

Rev. 02 — 9 December 2008

20 of 29

LM75B

NXP Semiconductors

Digital temperature sensor and thermal watchdog

13. Package outline

SO8: plastic small outline package; 8 leads; body width 3.9 mm

SOT96-1

D

E

A

X

v

c

y

H

M

A

E

Z

5

8

Q

A

2

A

(A )

3

A

1

pin 1 index

θ

L

p

L

1

4

e

w

M

detail X

b

p

0

2.5

5 mm

scale

DIMENSIONS (inch dimensions are derived from the original mm dimensions)

A

(1)

(2)

UNIT

A

b

c

D

E

e

H

L

p

Q

v

w

y

Z

θ

1

2

3

p

E

max.

0.25

0.10

1.45

1.25

0.49

0.36

0.25

0.19

5.0

4.8

4.0

3.8

6.2

5.8

1.0

0.4

0.7

0.6

0.7

0.3

mm

1.27

0.05

1.05

0.041

1.75

0.25

0.01

0.25

0.01

0.25

0.1

8^o

0^o

0.010 0.057

0.004 0.049

0.019 0.0100 0.20

0.014 0.0075 0.19

0.16

0.15

0.244

0.228

0.039 0.028

0.016 0.024

0.028

0.012

inches 0.069

0.01 0.004

Notes

1. Plastic or metal protrusions of 0.15 mm (0.006 inch) maximum per side are not included.

2. Plastic or metal protrusions of 0.25 mm (0.01 inch) maximum per side are not included.

REFERENCES

OUTLINE

EUROPEAN

PROJECTION

ISSUE DATE

VERSION

IEC

JEDEC

JEITA

99-12-27

03-02-18

SOT96-1

076E03

MS-012

Fig 20. Package outline SOT96-1 (SO8)

LM75B_2

Product data sheet

Rev. 02 — 9 December 2008

21 of 29

LM75B

NXP Semiconductors

Digital temperature sensor and thermal watchdog

TSSOP8: plastic thin shrink small outline package; 8 leads; body width 3 mm

SOT505-1

D

E

A

X

c

y

H

v

M

A

E

Z

5

8

A

(A )

2

A

3

A

1

pin 1 index

θ

L

p

L

1

4

detail X

e

w M

b

p

0

2.5

5 mm

scale

DIMENSIONS (mm are the original dimensions)

A

(1)

(2)

(1)

A

b

c

D

E

e

H

E

L

p

UNIT

v

w

y

Z

θ

1

2

3

p

max.

0.15

0.05

0.95

0.80

0.45

0.25

0.28

0.15

3.1

2.9

3.1

2.9

5.1

4.7

0.7

0.4

0.70

0.35

6°

0°

mm

1.1

0.65

0.25

0.94

0.1

Notes

1. Plastic or metal protrusions of 0.15 mm maximum per side are not included.

2. Plastic or metal protrusions of 0.25 mm maximum per side are not included.

REFERENCES

OUTLINE

EUROPEAN

PROJECTION

ISSUE DATE

VERSION

IEC

JEDEC

JEITA

99-04-09

03-02-18

SOT505-1

Fig 21. Package outline SOT505-1 (TSSOP8)

LM75B_2

Product data sheet

Rev. 02 — 9 December 2008

22 of 29

LM75B

NXP Semiconductors

Digital temperature sensor and thermal watchdog

XSON8U: plastic extremely thin small outline package; no leads;

8 terminals; UTLP based; body 3 x 2 x 0.5 mm

SOT996-2

D

B

A

E

A

1

detail X

terminal 1

index area

e

1

C

M

v

C

A

B

b

e

L

1

y

w

C

1

4

L

2

L

8

5

X

0

1

2 mm

scale

DIMENSIONS (mm are the original dimensions)

A

UNIT

A

1

b

D

E

e

1

L

v

w

y

1

2

max

0.05 0.35

0.00 0.15

2.1

1.9

3.1

2.9

0.5

0.3

0.15

0.05

0.6

0.4

mm

0.5

1.5

0.1

0.05 0.05

0.1

REFERENCES

OUTLINE

VERSION

EUROPEAN

PROJECTION

ISSUE DATE

IEC

- - -

JEDEC

JEITA

07-12-18

07-12-21

SOT996-2

- - -

Fig 22. Package outline SOT996-2 (XSON8U)

LM75B_2

Product data sheet

Rev. 02 — 9 December 2008

23 of 29

LM75B

NXP Semiconductors

Digital temperature sensor and thermal watchdog

14. Soldering of SMD packages

This text provides a very brief insight into a complex technology. A more in-depth account

of soldering ICs can be found in Application Note AN10365 “Surface mount reﬂow

soldering description”.

14.1 Introduction to soldering

Soldering is one of the most common methods through which packages are attached to

Printed Circuit Boards (PCBs), to form electrical circuits. The soldered joint provides both

the mechanical and the electrical connection. There is no single soldering method that is

ideal for all IC packages. Wave soldering is often preferred when through-hole and

Surface Mount Devices (SMDs) are mixed on one printed wiring board; however, it is not

suitable for ﬁne pitch SMDs. Reﬂow soldering is ideal for the small pitches and high

densities that come with increased miniaturization.

14.2 Wave and reﬂow soldering

Wave soldering is a joining technology in which the joints are made by solder coming from

a standing wave of liquid solder. The wave soldering process is suitable for the following:

• Through-hole components

• Leaded or leadless SMDs, which are glued to the surface of the printed circuit board

Not all SMDs can be wave soldered. Packages with solder balls, and some leadless

packages which have solder lands underneath the body, cannot be wave soldered. Also,

leaded SMDs with leads having a pitch smaller than ~0.6 mm cannot be wave soldered,

due to an increased probability of bridging.

The reﬂow soldering process involves applying solder paste to a board, followed by

component placement and exposure to a temperature proﬁle. Leaded packages,

packages with solder balls, and leadless packages are all reﬂow solderable.

Key characteristics in both wave and reﬂow soldering are:

• Board speciﬁcations, including the board ﬁnish, solder masks and vias

• Package footprints, including solder thieves and orientation

• The moisture sensitivity level of the packages

• Package placement

• Inspection and repair

• Lead-free soldering versus SnPb soldering

14.3 Wave soldering

Key characteristics in wave soldering are:

• Process issues, such as application of adhesive and ﬂux, clinching of leads, board

transport, the solder wave parameters, and the time during which components are

exposed to the wave

• Solder bath speciﬁcations, including temperature and impurities

LM75B_2

Product data sheet

Rev. 02 — 9 December 2008

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LM75B

NXP Semiconductors

Digital temperature sensor and thermal watchdog

14.4 Reﬂow soldering

Key characteristics in reﬂow soldering are:

• Lead-free versus SnPb soldering; note that a lead-free reﬂow process usually leads to

higher minimum peak temperatures (see Figure 23) than a SnPb process, thus

reducing the process window

• Solder paste printing issues including smearing, release, and adjusting the process

window for a mix of large and small components on one board

• Reﬂow temperature proﬁle; this proﬁle includes preheat, reﬂow (in which the board is

heated to the peak temperature) and cooling down. It is imperative that the peak

temperature is high enough for the solder to make reliable solder joints (a solder paste

characteristic). In addition, the peak temperature must be low enough that the

packages and/or boards are not damaged. The peak temperature of the package

depends on package thickness and volume and is classiﬁed in accordance with

Table 19 and 20

Table 19. SnPb eutectic process (from J-STD-020C)

Package thickness (mm) Package reﬂow temperature (°C)

Volume (mm³)

< 350

235

≥ 350

220

< 2.5

≥ 2.5

220

Table 20. Lead-free process (from J-STD-020C)

Package thickness (mm) Package reﬂow temperature (°C)

Volume (mm³)

< 350

260

350 to 2000

> 2000

260

< 1.6

260

250

245

1.6 to 2.5

> 2.5

260

245

250

245

Moisture sensitivity precautions, as indicated on the packing, must be respected at all

times.

Studies have shown that small packages reach higher temperatures during reﬂow

soldering, see Figure 23.

LM75B_2

Product data sheet

Rev. 02 — 9 December 2008

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LM75B

NXP Semiconductors

Digital temperature sensor and thermal watchdog

maximum peak temperature

= MSL limit, damage level

temperature

minimum peak temperature

= minimum soldering temperature

peak

temperature

time

001aac844

MSL: Moisture Sensitivity Level

Fig 23. Temperature proﬁles for large and small components

For further information on temperature proﬁles, refer to Application Note AN10365

“Surface mount reﬂow soldering description”.

15. Abbreviations

Table 21. Abbreviations

Acronym

A-to-D

CDM

Description

Analog-to-Digital

Charged Device Model

ElectroStatic Discharge

Human Body Model

Inter-Integrated Circuit bus

Input/Output

ESD

HBM

I²C-bus

I/O

LSB

Lease Signiﬁcant Bit

Least Signiﬁcant Byte

Machine Model

LSByte

MM

MSB

Most Signiﬁcant Bit

Most Signiﬁcant Byte

Power-On Reset

MSByte

POR

LM75B_2

Product data sheet

Rev. 02 — 9 December 2008

26 of 29

LM75B

NXP Semiconductors

Digital temperature sensor and thermal watchdog

16. Revision history

Table 22. Revision history

Document ID

LM75B_2

Release date

Data sheet status

Change notice

Supersedes

20081209

Product data sheet

-

LM75B_1

Modiﬁcations:

• added XSON8U package option (affects Section 2 “Features”, Table 1 “Ordering information”,

Section 6.1 “Pinning”, Table 14 “LM75A and LM75B comparison”, Section 13 “Package outline”)

LM75B_1

20081204

Product data sheet

-

LM75B_2

Product data sheet

Rev. 02 — 9 December 2008

27 of 29

LM75B

NXP Semiconductors

Digital temperature sensor and thermal watchdog

17. Legal information

17.1 Data sheet status

Document status^[1][2]

Product status^[3]

Development

Deﬁnition

Objective [short] data sheet

This document contains data from the objective speciﬁcation for product development.

This document contains data from the preliminary speciﬁcation.

This document contains the product speciﬁcation.

Preliminary [short] data sheet Qualiﬁcation

Product [short] data sheet Production

[1]

[2]

[3]

Please consult the most recently issued document before initiating or completing a design.

The term ‘short data sheet’ is explained in section “Deﬁnitions”.

The product status of device(s) described in this document may have changed since this document was published and may differ in case of multiple devices. The latest product status

information is available on the Internet at URL http://www.nxp.com.

to result in personal injury, death or severe property or environmental

17.2 Deﬁnitions

damage. NXP Semiconductors accepts no liability for inclusion and/or use of

NXP Semiconductors products in such equipment or applications and

therefore such inclusion and/or use is at the customer’s own risk.

Draft — The document is a draft version only. The content is still under

internal review and subject to formal approval, which may result in

modiﬁcations or additions. NXP Semiconductors does not give any

representations or warranties as to the accuracy or completeness of

information included herein and shall have no liability for the consequences of

use of such information.

Applications — Applications that are described herein for any of these

products are for illustrative purposes only. NXP Semiconductors makes no

representation or warranty that such applications will be suitable for the

speciﬁed use without further testing or modiﬁcation.

Limiting values — Stress above one or more limiting values (as deﬁned in

the Absolute Maximum Ratings System of IEC 60134) may cause permanent

damage to the device. Limiting values are stress ratings only and operation of

the device at these or any other conditions above those given in the

Characteristics sections of this document is not implied. Exposure to limiting

values for extended periods may affect device reliability.

Short data sheet — A short data sheet is an extract from a full data sheet

with the same product type number(s) and title. A short data sheet is intended

for quick reference only and should not be relied upon to contain detailed and

full information. For detailed and full information see the relevant full data

sheet, which is available on request via the local NXP Semiconductors sales

ofﬁce. In case of any inconsistency or conﬂict with the short data sheet, the

full data sheet shall prevail.

Terms and conditions of sale — NXP Semiconductors products are sold

subject to the general terms and conditions of commercial sale, as published

at http://www.nxp.com/proﬁle/terms, including those pertaining to warranty,

intellectual property rights infringement and limitation of liability, unless

explicitly otherwise agreed to in writing by NXP Semiconductors. In case of

any inconsistency or conﬂict between information in this document and such

terms and conditions, the latter will prevail.

17.3 Disclaimers

General — Information in this document is believed to be accurate and

reliable. However, NXP Semiconductors does not give any representations or

warranties, expressed or implied, as to the accuracy or completeness of such

information and shall have no liability for the consequences of use of such

information.

No offer to sell or license — Nothing in this document may be interpreted

or construed as an offer to sell products that is open for acceptance or the

grant, conveyance or implication of any license under any copyrights, patents

or other industrial or intellectual property rights.

Right to make changes — NXP Semiconductors reserves the right to make

changes to information published in this document, including without

limitation speciﬁcations and product descriptions, at any time and without

notice. This document supersedes and replaces all information supplied prior

to the publication hereof.

17.4 Trademarks

Notice: All referenced brands, product names, service names and trademarks

are the property of their respective owners.

Suitability for use — NXP Semiconductors products are not designed,

authorized or warranted to be suitable for use in medical, military, aircraft,

space or life support equipment, nor in applications where failure or

malfunction of an NXP Semiconductors product can reasonably be expected

I²C-bus — logo is a trademark of NXP B.V.

18. Contact information

For more information, please visit: http://www.nxp.com

For sales ofﬁce addresses, please send an email to: salesaddresses@nxp.com

LM75B_2

Product data sheet

Rev. 02 — 9 December 2008

28 of 29

LM75B

NXP Semiconductors

Digital temperature sensor and thermal watchdog

19. Contents

1

2

3

4

5

General description . . . . . . . . . . . . . . . . . . . . . . 1

17.3

17.4

Disclaimers. . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Trademarks . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Ordering information. . . . . . . . . . . . . . . . . . . . . 2

Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . 3

18

19

Contact information . . . . . . . . . . . . . . . . . . . . 28

Contents. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

6

6.1

6.2

Pinning information. . . . . . . . . . . . . . . . . . . . . . 3

Pinning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Pin description . . . . . . . . . . . . . . . . . . . . . . . . . 4

7

7.1

7.2

7.2.1

7.3

Functional description . . . . . . . . . . . . . . . . . . . 4

General operation. . . . . . . . . . . . . . . . . . . . . . . 4

I²C-bus serial interface . . . . . . . . . . . . . . . . . . . 6

Bus fault time-out . . . . . . . . . . . . . . . . . . . . . . . 6

Slave address . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Register list. . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Pointer register . . . . . . . . . . . . . . . . . . . . . . . . . 7

Conﬁguration register . . . . . . . . . . . . . . . . . . . . 7

Temperature register. . . . . . . . . . . . . . . . . . . . . 8

Overtemperature shutdown threshold (Tos)

7.4

7.4.1

7.4.2

7.4.3

7.4.4

and hysteresis (Thyst) registers . . . . . . . . . . . . 9

OS output and polarity . . . . . . . . . . . . . . . . . . 10

OS comparator and interrupt modes . . . . . . . 10

OS fault queue . . . . . . . . . . . . . . . . . . . . . . . . 11

Shutdown mode . . . . . . . . . . . . . . . . . . . . . . . 11

Power-up default and power-on reset. . . . . . . 11

Protocols for writing and reading the registers 12

7.5

7.6

7.7

7.8

7.9

7.10

8

Application design-in information . . . . . . . . . 15

Typical application. . . . . . . . . . . . . . . . . . . . . . 15

LM75A and LM75B comparison . . . . . . . . . . . 15

Temperature accuracy . . . . . . . . . . . . . . . . . . 16

Noise effect. . . . . . . . . . . . . . . . . . . . . . . . . . . 16

8.1

8.2

8.3

8.4

9

Limiting values. . . . . . . . . . . . . . . . . . . . . . . . . 17

Recommended operating conditions. . . . . . . 17

Static characteristics. . . . . . . . . . . . . . . . . . . . 18

Dynamic characteristics . . . . . . . . . . . . . . . . . 20

Package outline . . . . . . . . . . . . . . . . . . . . . . . . 21

10

11

12

13

14

Soldering of SMD packages . . . . . . . . . . . . . . 24

Introduction to soldering . . . . . . . . . . . . . . . . . 24

Wave and reﬂow soldering . . . . . . . . . . . . . . . 24

Wave soldering . . . . . . . . . . . . . . . . . . . . . . . . 24

Reﬂow soldering . . . . . . . . . . . . . . . . . . . . . . . 25

14.1

14.2

14.3

14.4

15

16

Abbreviations. . . . . . . . . . . . . . . . . . . . . . . . . . 26

Revision history. . . . . . . . . . . . . . . . . . . . . . . . 27

17

17.1

17.2

Legal information. . . . . . . . . . . . . . . . . . . . . . . 28

Data sheet status . . . . . . . . . . . . . . . . . . . . . . 28

Deﬁnitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Please be aware that important notices concerning this document and the product(s)

described herein, have been included in section ‘Legal information’.

For more information, please visit: http://www.nxp.com

For sales office addresses, please send an email to: salesaddresses@nxp.com

Date of release: 9 December 2008

Document identifier: LM75B_2


型号：	LM75BDP
厂家：	NXP
描述：	Digital temperature sensor and thermal watchdog 数字温度传感器和热看门狗传感器换能器温度传感器输出元件
文件：	总29页 (文件大小：164K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

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