AS1181 datasheet(34/92 Pages) AMSOSRAM

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AS1181

Functional description

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DS001139 • v3-00 • 2026-Apr-01

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7.2.4.1

Periodic BIST sequence

The periodic BIST sequence bypasses the external LEDs by using an internal RLOAD resistor

to verify the operation of the current sinks.

During production testing, the device is calibrated so that the voltage across the internal

RLOAD resistor corresponds to a known current sunk by each LN current source. Each LN

current source can be individually connected to the RLOAD circuit.

During operation, the device verifies that the measured voltage across RLOAD for a given

current matches the reference value stored in the OTP. This check also accounts for device

temperature and the temperature coefficient of the polysilicon resistor used for RLOAD.

The periodic BIST runs after an illumination event on one channel, then advances to the next

channel on the following illumination cycle, completing all channels after eight illumination

cycles.

During startup BIST, all current sinks are tested using the RLOAD Startup configuration.

The periodic BIST timing can be configured or disabled with TST_INTERVAL register (Address

0x1A40).

7.2.5

Temperature shutdown

The device integrates an on-chip temperature supervision for over and under temperature

situations. If the device is exposed to too high or too low temperatures it will shut down the

current sinks, sets respective interrupt and inform the host.

AS1181 Datasheet(PDF) 34 Page - ams-OSRAM AG