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LM61

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SNIS121J – JUNE 1999 – REVISED NOVEMBER 2016

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8.2.1.2 Detailed Design Procedure

The LM61 is a simple temperature sensor that provides an analog output. Therefore, design requirements related

to layout outweigh other requirements in importance. See Layout for more information.

8.2.1.2.1

Capacitive Loads

The LM61 handles capacitive loading well. Without any special precautions, the LM61 can drive any capacitive

load as shown in Figure 12. Over the specified temperature range the LM61 has a maximum output impedance

of 5 kΩ. In an extremely noisy environment it may be necessary to add some filtering to minimize noise pickup. It

is recommended that 0.1-µF capacitor be added between +VS and GND to bypass the power-supply voltage, as

shown in Figure 13. In a noisy environment it may be necessary to add a capacitor from VOUT to ground. A 1-µF

output capacitor with the 5-kΩ maximum output impedance forms a 32-Hz lowpass filter. Because the thermal

time constant of the LM61 is much slower than the 5-ms time constant formed by the RC, the overall response

time of the LM61 is not significantly affected. For much larger capacitors this additional time lag increases the

overall response time of the LM61.

Figure 12. LM61 No Decoupling Required for Capacitive Load

Figure 13. LM61 with Filter for Noisy Environments