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AS8530

Preliminary Data Sheet - D e t a i l e d D e s c r i p t i o n

7.1.7 LIN Transceiver

The transceiver provides short circuit limitation, hardware watchdog and over temperature shut down features. The TX watchdog timer is active

when TX is pulled low (active). As soon as the TX watchdog timeout occurs, the LIN bus is released from dominant state to recessive state. The

LIN transceiver has a pull-up resistor (for the slave node; extra resistor externally for the master node) to the VSUP. A diode protection is

available to protect it from back supply from bus line.

The LIN transmitter has the basic functionality of relaying the data from the micro-controller on to the LIN. The data on the LIN needs to have

controlled slew to have reduced EMI. The receiver relays the data from the LIN to the micro-controller. This transmitter has optimized EMC

performance across different loading conditions conforming to the LIN 2.1 standards. The wake-up detects a wake up event on the LIN.

7.2 Operating Modes and States

The AS8530 provides four main operating modes “normal”, “sleep/stand-by” (programmed by OTP), “temporary shutdown” and “thermal

shutdown”. The LIN transceiver can be programmed to operate with lower slew in the normal mode. Refer to Table 12 for a detailed description

on transition for each mode.

7.2.1 Normal Mode

This is the mode after the power-up. In normal mode, LDO, LIN Transceiver, Window Watchdog, Resistive divider and the line drivers are all

turned on. All the blocks are completely functional. LDO is now capable of delivering maximum load current possible as per the device

specifications. The LIN Transceiver is capable of sending the TX data from microcontroller to the LIN bus at a maximum rate of 20Kbps.

Resistive divider is used to attenuate the battery voltage and relay drivers are used to drive the relay. EN signal is set to high and LIN, TX, RX

the diagnostic register, which can be read through the 2-wire interface.

7.2.2 Standby Mode

Standby mode is a functional low-power mode where the LDO is switched into a low-power state with low drive capability and lower accuracy of

the output voltage. LIN Transceiver is disabled. The LIN wake-up circuit and over-temperature monitor circuit is enabled. Window watchdog, TX

timeout watchdog, Resistive divider, relay driver circuits are disabled. EN pin held low in this mode. TX pin is in recessive state (high). CS is

7.2.3 Sleep Mode

As a factory programming option on request the AS8530 offers as a replacement to the standby mode with sleep mode. Sleep mode is the most

current saving mode. If EN is held low, the LDO, LIN Transceiver, the gate drivers, the resistive divider and the reset and window watchdog unit

bus is in recessive state (high). Only wake-up possible is through remote wake-up, through LIN pin, pulling it to dominant state for 100µs typical

(low), can change the state of the system.

7.2.4 Temporary Shutdown Mode

have a pin for the reset functionality. This provides an alternative way to reset those components interfacing with AS8530. This mode is default

disabled but can be enabled by an OTP option. In this mode, all internal modules supplied by the LDO are disabled. Only the oscillator, control

along with the LIN wake-up circuit is powered down. No remote wake-up functionality is possible. LIN bus enters into recessive state. The

transition will be controller by register bit in configuration register.