MC33690 Datasheet, PDF (8/24 Pages) Motorola, Inc – Standalone Tag Reader Circuit

Freescale S^Me^Cm³³i⁶c⁹o⁰nductor, Inc.
ISO 9141 PHYSICAL INTERFACE
This interface module is fully compatible with
the ISO 9141 norm describing the diagnosis line.
It includes one transmitter (pin K) and 2 receivers
(pins K and AM).
The input stages consist of high voltage CMOS
triggers. The thresholds are ratiometric to VSUP.
A ground referenced current source (2.5µA typ.)
pulls down the input when unconnected.
When a negative voltage is applied on the K or
AM lines, the input current is internally limited by
a 2kΩ resistor (typ.) in series with a diode.
any capacitive load and protects against short
circuit to the battery voltage. An overtemperature
protection shuts the driver down when the
junction temperature exceeds 150°C (typ). Once
shut down by the overtemperature protection,
the driver can be switched on again :
- if the junction temperature has decreased
below the threshold,
- and by applying an off/on command, coming
either from the demodulator in configurations A
and B or directly applied on the input Tx in
configuration C (see pin K status in table 1 page
9).
A current limitation allows the transmitter to drive
The electromagnetic emission is reduced thanks
to the voltage slew rate control (5V/µs typ.).
Figure 5 : ISO 9141interface
VDD
AM data
From configuration controller
VDD
Rx
From configuration controller
Tag Reader module output
VDD
Tx
2kΩ
VSUP
GND
VSUP
2.5µA
GND
2kΩ
L line
AM
2.5µA
GND GND
Over temperature
detector
Command
VBAT
K line
K
Current limitation
© Motorola, Inc., 2002.
F^Mo^Or ^TM^Oo^Rr^Oe^LAIn^Sfo^EMrm^ICa^Ot^Nio^Dn^UCO^Tn^ORT^Sh^Pis^ROP^Dro^Ud^Cu^TSct,
Go to: www⁸.freescale.com
revision 4.8, 5 February 2002