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AS1923

Datasheet - Application In form atio n

User-Adjustable Thresholds

The AS1923 provides several voltage monitoring values as well as user-adjustable reset thresholds.

The threshold voltage at each adjustable INx input is typically 1.23V. To monitor a voltage >1.23V, connect a resistor-divider network to the circuit

as shown in Figure 13.

Figure 13. Setting User-Adjustable Thresholds

Note:

Because the AS1923 has a guaranteed input current of ±0.1µA on its adjustable inputs, resistor values up to 100k

Ω can be used for

Unused Inputs

The IN2 input must always be used for normal operation (AS1923 power-supply pin). Otherwise, in cases where one or more of the AS1923

monitoring inputs will not be used, these inputs must be tied to a supply voltage greater in magnitude than their specified threshold voltages.

Notes:

1. For unused IN3 or IN4 applications with positive thresholds (fixed or adjustable), the inputs can be connected directly to the IN2 supply.

2. For unused IN4 options with negative thresholds, the input must be tied to a more negative supply.

3. Unused pins must not be connected to ground or allowed to float.

+

–

+

–

1.23V

(EQ 1)

1,23V

+

-------------------

×

=

1,23V

----------------1

–

⎝⎠

⎛⎞

×

=

(EQ 2)