Introduction

STOD1412

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5.1

Setting output voltage

The output voltage can be set using external network resistors.

The positive output voltage range is 4.3 V minimum up to a maximum of 6.0 V. It is obtained

by connecting FB1 to OUT1 through R2, and FB1 to PGND through R1 (see application

circuit). The positive output value can be calculated using the following formula:

The negative output voltage range is -8.0 V minimum up to a maximum of -2.0 V. It is

obtained connecting FB2 to VREF through R3 and FB2 to PGND through R4 (see

application circuit). The value of negative output can be calculated using the following

formula:

5.2

Under voltage lockout

The device includes an under voltage lockout circuit. When the STOD1412 is enabled (EN

pin is pulled high), the device will be OFF until the input voltage reaches the 2.55 V

threshold. The UVLO circuit has a hysteresis of 50 mV, so once the device is on, it will keep

5.3

Enable

This function allows switching ON and OFF the device using a logic level signal. If the EN

pin is pulled high the device turns ON, given that the input voltage is higher than the under

voltage lockout threshold. Pulling the EN pin low turns off the device regardless of the UVLO

state. In this condition the current consumption is reduced to lower than 1 µA

5.4

Load disconnect

When the device is turned OFF, there is no path for the current to flow from the input power

supply to the load. In the device there are two switches that allow complete disconnection of

the load. This function is useful to improve battery life when the device is not in operation.

5.5

Soft start and inrush current

The device includes a soft start feature to limit inrush current when the device is turned on.

This function is added to minimize battery loading at start-up.

5.6

Current limit

The step-up and inverter converters include peak current limit circuitry. The inductor peak

current cannot exceed 900mA for the step-up stage and 1A for the inverting stage.