Datasheet
OPERATING STATES
Unpowered System
V V
sup sup_under
£
Standby Mode
Driver : Off
RXD: Low
INH: High (On)
Termination: 30 kW
EN = high
EN = low
EN = high
LIN Bus Wake-Up
or
Nwake Pin Wake-Up
V > V
EN = low
sup sup_under
V V
sup sup_under
£
V V
sup sup_under
£
V V
sup sup_under
£V > V
EN = high
sup sup_under
Sleep Mode
Driver : Off
RXD: Floating
INH: High impedance (Off)
Termination: Weak pullup
Normal Mode
Driver : On
RXD: LIN bus data
INH: High (On)
Termination: 30 kW
Normal Mode
Sleep Mode
TPIC1021A-Q1
www.ti.com
.......................................................................................................................................................... SLIS117A – AUGUST 2007 – REVISED JUNE 2009
Figure 1. Operating States Diagram
Table 1. Operating Modes
LIN BUS
MODE EN RXD INH TRANSMITTER COMMENTS
TERMINATION
Sleep Low Floating Weak current pullup High impedance Off
Wake-up event detected, waiting
Standby Low Low 30 k Ω (typ) High Off
on MCU to set EN
Normal High LIN bus data 30 k Ω (typ) High On LIN transmission up to 20 kbps
This is the normal operational mode, in which the receiver and driver are active, and LIN transmission up to the
LIN specified maximum of 20 kbps is supported. The receiver detects the data stream on the LIN bus and
outputs it on RXD for the LIN controller, where recessive on the LIN bus is a digital high, and dominate on the
LIN bus is digital low. The driver transmits input data on TXD to the LIN bus. Normal mode is entered as EN
transitions high while the TPIC1021A is in sleep or standby mode.
Sleep mode is the power saving mode for the TPIC1021A and the default state after power up (assuming EN is
low during power up). Even with the extremely low current consumption in this mode, the TPIC1021A can still
wake up from LIN bus via a wake-up signal, a low on NWake, or if EN is set high. The LIN bus and NWake are
filtered to prevent false wake-up events. The wake-up events must be active for their respective time periods
(t
LINBUS
, t
NWake
).
The sleep mode is entered by setting EN low.
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