LM56 datasheet(11/21 Pages) TI

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LM56

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SNIS120G – APRIL 2000 – REVISED FEBRUARY 2013

VREF AND VTEMP CAPACITIVE LOADING

Figure 16. Loading of VREF and VTEMP

The LM56 VREF and VTEMP outputs handle capacitive loading well. Without any special precautions, these outputs

can drive any capacitive load as shown in Figure 16.

NOISY ENVIRONMENTS

Over the specified temperature range the LM56 VTEMPoutput has a maximum output impedance of 1500Ω. In an

extremely noisy environment it may be necessary to add some filtering to minimize noise pickup. It is

recommended that 0.1

μF be added from V+ to GND to bypass the power supply voltage, as shown in Figure 16.

In a noisy environment it may be necessary to add a capacitor from the VTEMP output to ground. A 1 μF output

capacitor with the 1500

Ω output impedance will form a 106 Hz lowpass filter. Since the thermal time constant of

the VTEMP output is much slower than the 9.4 ms time constant formed by the RC, the overall response time of

the VTEMP output will not be significantly affected. For much larger capacitors this additional time lag will increase

the overall response time of the LM56.

APPLICATIONS CIRCUITS

Figure 17. Reducing Errors Caused by Bias Current

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LM56 Datasheet(PDF) 11 Page - Texas Instruments