Datasheet
LM75B All information provided in this document is subject to legal disclaimers. © NXP B.V. 2015. All rights reserved.
Product data sheet Rev. 6.1 — 6 February 2015 18 of 37
NXP Semiconductors
LM75B
Digital temperature sensor and thermal watchdog
V
OL(EVENT)
= 0.4 V
I
OL(sink)EVENT
= 3 mA
R
th(j-a)
= 56 C/W
Self heating due to power dissipation is:
(2)
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
I
2
C lines LOW when V
CC
is not supplied and therefore allow continued I
2
C-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
CC
pin.
• 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.
T56 3.60.40.4 30.4 1++ 56 C W 3.04 mW 0.17 C===