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AS8520

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

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 AS8520 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 AS8520. 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.

7.2.5 Thermal Shutdown State

disabled. No wake-up functionality is available. Window watchdog, TX timeout watchdog and LDO are completely turned off. Only the over-

on transition, see Table 14.

Table 14. Transition Table

Transition

Interface

Reg.

0x05

D0

Flags

From mode

To mode

LIN

RX

TX

EN

rwake Uvbat

OT

Uvcc

Comments

Normal

Mode

Stand-By

X-RS

X-H

2

H

3

H-L

3

L

X

X

inactive

inactive

TX is high for

Sleep

1

X-RS

X-H

2

H

3

H-L

3

L

X

X

inactive

set

TX is high for

1

Temporary

Shutdown

X-RS

X-H

2

X

H

3

H

X

X

inactive

set

The Control Bit is set

through the 4-Wire

SPI interface

Over-

Temperature

X-RS

X-H

2

XX

L

X

X

set

set

Temperature monitor

output asserted

(covered by scan)

Stand-By

Mode

Normal (LW)

X

H-X

2

X

L-H

3

L

X

X

inactive

inactive

Normal (RW)

X

H-X

2

H

X

L

set

X

inactive

inactive

Remote Wake up

Event occurred on

LIN

Temporary

Shutdown

RS

H

2

HL

H

3

XX

inactive

set

The Control Bit is set

through the 4-Wire

SPI interface

Over-

Temperature

RS

H

2

HL

L

X

X

set

set

Temperature monitor

output asserted

(covered by scan)