Voltage monitor and reset chip has BIST for ADAS

Voltage monitor and reset chip has BIST for ADAS

Called MAX16137, it has two forms of BIST (built-in self-test): one that checks the chip at power-up and a second that checks on-demand.

Just like any reset chip, it holds its reset output low as power-up progresses, then releases it high after a (factory settable) delay once the rail is established. It also detects under-voltage and over-voltage conditions. In the case of an over-voltage, the chip pulls both the reset pin low and an over-voltage indicator pin that can be used to shut down the potentially-offending regulator (see typical application circuit below).

At power up, around the time the power rails are established and reset is being released, the internal on-demand BIST generates fictitious under-voltage and over-voltage faults and, if the internal circuit does not respond properly, pulls reset low as well as the fault-indicating ‘BIST’ output pin.

A caveat here: do check the data sheet yourself – there is a bit more too it that the simplified version here. Back to the IC:

At any time during normal operation, BIST can be initiated by pulling the CLR/BIST input pin low. One of two things happens then, controlled by the NR input pin (see diagrams).

Voltage monitor and reset chip has BIST for ADAS

If NR is low, a reset is initiated while the test is in operation, and the result indicated through there BIST output – much like a power-up.

If NR is high, the test happens without a reset being asserted, with the result again indicated by the BIST pin.

Through factory settings, the IC’s nominal voltage can be anywhere from 0.5V to 5V in ~20mV increment.

Over-voltage and under-voltage thresholds are symmetrical about this, factory-trimmed from ±4% to ±11% in ±1% increments. Reset time-out is set at the factory between 200 to 1,500ms.

“Functional safety standards drive design direction in the automotive space,” according to the company. “Voltage monitors play a key role in reporting the health of power supplies. MAX16137 delivers both diagnostic and BIST at the chip level to help designers achieve system-wide functional safety for ADAS and other autonomous driving applications. The supervisory IC can be designed into a variety of automotive systems such as infotainment, body electronics, power, electric vehicle power powertrain and IoT systems.”

It comes in a 2 x 2mm, 8pin TDFN side-wettable package with exposed pad, and operates over -40°C to +125°C.

The MAX16137 product page is here, and the data sheet here.

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