CD1020 datasheet(17/56 Pages) NXP

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NXP Semiconductors

CD1020

General IC functional description

The CD1020 device interacts with many connections outside the module and near the end user. The IC detects changes in switch state

and reports the information to the MCU via the SPI protocol. The input pins generally connect to switches located outside the module and

in proximity to battery in car harnesses. Consequently, the IC must have some external protection including an ESD capacitor and series

resistors, to ensure the energy from the various pulses are limited at the IC.

The IC requires a blocking diode be used on the VBATP pin to protect from a reverse battery condition. The inputs are capable of surviving

reverse battery without a blocking diode, due to an internal blocking diode from the input to the power supply (VBATP). This arrangement

ensures that there is no backfeeding of voltage/current into the IC, when the voltage on the input is higher than the VBATP pin.

6.1

Battery voltage ranges

The CD1020 device operates from 6.0 V ≤ VBATP ≤ 36 V and is capable to withstand up to 40 V. Voltages in excess of 40 V must be

clamped externally in order to protect the IC from destruction. The VBATP pin must be isolated from the main battery node by a diode.

6.1.1

Load dump (overvoltage)

During load dump, the CD1020 operates properly up to the VBATP overvoltage. Voltages greater than load dump (~32 V) cause the current

sources to be limited to ~2.0 mA, but the register values are maintained. Upon leaving this overvoltage condition, the original setup is

returned and normal operation begins again.

6.1.2

Jump start (double battery)

During a jump start (double battery) condition, the device functions normally and meets all the specified parametric values. No internal

faults are set and no abnormal operation noted as a result of operating in this range.

6.1.3

Normal battery range

The normal voltage range is fully functional with all parametrics in the given specification.

6.1.4

Undervoltage

In the undervoltage range, the SPI can work normally, but the device functions are not guaranteed.

6.1.5

Undervoltage lockout

During undervoltage lockout, the MISO output is tri-stated to avoid any data from being transmitted from the CD1020. Any CS_B pulses

are ignored in this voltage range. If the battery enters this range at any point (even during a SPI word), the CD1020 ignores the word and

enters lockout mode. A SPI bit register is available to notify the MCU that the CD1020 has seen an undervoltage lockout condition once

the battery is high enough to leave this range.

6.1.6

Power-On-Reset (POR) activated

The Power-On-Reset is activated when the VBATP is within the 2.7 V to 3.8 V range. During the POR all SPI registers are reset to default

values and SPI operation is disabled. The CD1020 is initialized after the POR is de-asserted. A SPI bit in the device configuration register

is used to note a POR occurrence and all SPI registers are reset to the default values.

6.1.7

No operation

The device does not function and no switch detection is possible.

CD1020 Datasheet(PDF) 17 Page - NXP Semiconductors

CD1020 Datasheet(HTML) 17 Page - NXP Semiconductors

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