LM75BGD,125 NXP Semiconductors, LM75BGD,125 Datasheet - Page 16

• Manufacturer Part Number: LM75BGD,125
• Description: IC TEMP SENSOR DGTL 8-UXSON
• Manufacturer: NXP Semiconductors

Specifications of LM75BGD,125

• Package / Case: 8-XSON
• Function: Temp Sensor, Watchdog
• Topology: ADC (Sigma Delta), Comparator, Oscillator, Register Bank
• Sensor Type: Internal
• Sensing Temperature: -55°C ~ 125°C
• Output Type: I²C™
• Output Alarm: No
• Output Fan: Yes
• Voltage - Supply: 2.8 V ~ 5.5 V
• Operating Temperature: -55°C ~ 125°C
• Mounting Type: Surface Mount
• Temperature Threshold: + 80 C
• Full Temp Accuracy: +/- 3 C
• Digital Output - Bus Interface: I2C
• Digital Output - Number Of Bits: 11
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 2.8 V
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 55 C
• Supply Current: 100 uA
• Temperature Sensor Function: Temp Sensor
• Operating Temperature (max): 125C
• Operating Temperature Classification: Military
• Operating Supply Voltage (typ): 3.3/5V
• Operating Supply Voltage (max): 5.5V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant
• Other names: 568-4769-2; 935288239125

NXP Semiconductors
[5]
LM75B_2
Product data sheet
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
about 10 ms. Therefore, the conversion period (T
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
8.4 Noise effect
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.
The LM75B device design includes the implementation of basic features for a good noise
immunity:
However, good layout practices and extra noise filters are recommended when the device
is used in a very noisy environment:
•
•
•
•
•
•
•
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
I
operation if the LM75B is de-powered.
Use decoupling capacitors at V
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.
2
C lines LOW when V
conv
) time of about 100 ms to complete a conversion, the LM75B takes only about
conv
Rev. 02 — 9 December 2008
) is the same, but the temperature conversion time (t
CC
is not supplied and therefore allow continued I
CC
Digital temperature sensor and thermal watchdog
pin.
CC
, the LM75B will not hold the
conv(T)
) is different between the
© NXP B.V. 2008. All rights reserved.
1
10
LM75B
2
of the period, or
C-bus
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