AS1310 datasheet(19/30 Pages) AMSCO

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[v1-11] 2015-Jan-28

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AS1310 − Application Information

Power-OK and Low-Battery-Detect Functionality

LBO goes low in startup mode as well as during normal

operation if:

• The voltage at the LBI pin is below LBI threshold (0.6V).

This can be used to monitor the battery voltage.

• LBI pin is connected to GND and VOUT is below 92.5% of

its nominal value. LBO works as a power-OK signal in this

case.

The LBI pin can be connected to a resistive-divider to monitor

a particular definable voltage and compare it with a 0.6V

internal reference. If LBI is connected to GND an internal

resistive-divider is activated and connected to the output.

Therefore, the Power-OK functionality can be realized with no

additional external components.

The Power-OK feature is not active during shutdown and

provides a power-ON-reset function that can operate down to

VIN = 0.7V. A capacitor to GND may be added to generate a

power-ON-reset delay. To obtain a logic-level output, connect

a pull-up resistor R3 from pin LBO to pin VOUT. Larger values for

this resistor will help to minimize current consumption; a 100k

resistor is perfect for most applications (see Figure 20).

For the circuit shown in the left of Figure 19, the input bias

current into LBI is very low, permitting large-value

resistor-divider networks while maintaining accuracy. Place the

resistor-divider network as close to the device as possible. Use

a defined resistor for R2 and then calculate R1 as:

Where: VLBI is 0.6V ±30mV

(EQ18)

LBI

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AS1310 Datasheet(PDF) 19 Page - ams AG