LM56BIM National Semiconductor, LM56BIM Datasheet - Page 11

• Manufacturer Part Number: LM56BIM
• Description: IC, LOW POWER THERMOSTAT, ± 2°C, 8-SOIC
• Manufacturer: National Semiconductor

Specifications of LM56BIM

• Ic Output Type: Digital
• Sensing Accuracy Range: ± 2°C
• Supply Current: 230µA
• Supply Voltage Range: 2.7V To 10V
• Sensor Case Style: SOIC
• No. Of Pins: 8
• Termination Type: SMD
• Filter Terminals: SMD
• Rohs Compliant: No
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

where I
Similarly, bias current affect on V
where I
B
B
= 300 nA (the maximum specified error).
= 300 nA (the maximum specified error).
FIGURE 6. Audio Power Amplifier Overtemperature Detector
T2
can be defined by:
11
The current shown in
detector for power devices. In this example, an audio power
amplifier IC is bolted to a heat sink and an LM56 Celsius tem-
perature sensor is mounted on a PC board that is bolted to
the heat sink near the power amplifier. To ensure that the
sensing element is at the same temperature as the heat sink,
the sensor's leads are mounted to pads that have feed
throughs to the back side of the PC board. Since the LM56 is
sensing the temperature of the actual PC board the back side
of the PC board also has large ground plane to help conduct
the heat to the device. The comparator's output goes low if
the heat sink temperature rises above a threshold set by R1,
R2, and the voltage reference. This fault detection output from
the comparator now can be used to turn on a cooling fan. The
circuit as shown in design to turn the fan on when heat sink
temperature exceeds about 80°C, and to turn the fan off when
the heat sink temperature falls below approximately 75°C.
Figure 6
is a simple overtemperature
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