Motorola MC33690DW Datasheet

MOTOROLA

SEMICONDUCTOR TECHNICAL

Standalone Tag Reader Circuit

Order this document

by MC33690/D

MC33690

STANDALONE

STARC

The Standalone Tag Reader Circuit (STARC) is an integrated circuit dedicated to the automotive immobilizer applications. It combines on the same chip all the circuitry to interface with a transponder : antenna drivers and demodulator. A low dropout voltage regulator and a physical interface fully compatible with the ISO 9141 norm are also available.

The Standalone Tag Reader Circuit is fabricated with the SMARTMOS metal, 1.4µm, 45V technology, combining CMOS and bipolar devices.

• Contactless 125kHz tag reader module :

- Self synchronous sample & hold demodulator

- Amplitude or phase modulation detection

- High sensitivity

- Fast “read after write“ demodulator settling time

- Low resistance and high current antenna drivers :

2Ω @ 150mA (typ.)

- Bidirectionnal data transmission

- Multi tag, multi scheme operation.

• Low dropout voltage regulator :

- Wide input supply voltage range :

from 5.5V up to 40V

- Output current capability up to 150mA DC with an

external power transistor

- 5V output voltage with a ± 5% accuracy

- Low voltage reset function

- Low current consumption in standby mode :

300µA (typ.).

• ISO 9141 transmitter and receiver module :

- Input voltage thresholds ratiometric to the supply

voltage

- Current limitation

- Ouput slew rate control

- No external protection device required.

3.5 technology. This process is a double layer

TAG READER

CIRCUIT

DW SUFFIX

Plastic Package

CASE 751D

SO - 20

Pin Connections

VSUP

SOURCE

GATE

TD1

VSS

VDD

TD2

MODE1

MODE2

ORDERING INFORMATION

XTAL1

XTAL2

LVR

DOUT

CEXT

1110

AGND

This document contains information on a new product under development. Motorola reserves the right to change or discontinue this product without notice.

REV 4.8

Device

MC33690DW

Operating

Junction

Tem p e r a t ure

Range

= -40°C to

125°C

Package

SOIC 20

BLOCK DIAGRAM

Optional : external N channel MOS required for sourced current > 50mA. A recommended reference is MMFT 3055VL from Motorola.

MC33690

Figure 1 : Standalone Tag Reader Circuit

VBAT

VDD

VSUP

GATE

SOURCE

VDD

10µF

VSS

EXT

10nF

TD1

TD2

CEXT

AGND

Voltage Regulator

Tag Reader

LVR

8MHz

XTAL1

XTAL2

MODE1

MODE2

DOUT

VBAT

510Ω

ISO 9141 Interface

MOTOROLA SEMICONDUCTORS PRODUCTS

revision 4.8, 5 February 2002

MAXIMUM RATINGS

Supply voltage V

Supply voltage without using the voltage regulator (V

= VDD)

SUP

Voltage on SOURCE V

Current into/from GATE 0 mA

MC33690

Rating Symbol Value Unit

VSS-0.3 to +40 V

VSS-0.3 to +7 V

-0.3 to +40 V

SUP

Voltage on GATE V

Voltage on pins : MODE1/2, CEXT, DOUT, LVR, XTAL1/2, Rx, Tx

Voltage on RD ±10 V

Voltage on K and AM V

Current on TD1 & TD2 (Drivers on & off)

Voltage on AGND VSS±0.3 V

ESD voltage capability (HBM, see note 1) ±2000 V

ESD voltage capability (MM, see note 1) ±200 V

Solder heat resistance test (10s) 260 °C

Junction temperature T

Storage temperature T

Note 1 :

Human Body model, AEC-Q100-002 Rev. C. Machine Model, AEC-Q100-003 Rev. E.

THERMAL CHARACTERISTIC

-0.3 V

-0.3 to V

-3 to 40 V

+0.3 V

±300 mA

170 °C

-65 to +150 °C

Junction to ambiant thermal resistance (SOIC20) R

Characteristic Symbol Value Unit

MOTOROLA SEMICONDUCTORS PRODUCTS

80 °C/W

revision 4.8, 5 February 2002

PIN FUNCTION DESCRIPTION

Pin Function Description

1 VSUP Power supply

2 SOURCE External N channel transistor source

3 GATE External N channel transistor gate

4 TD1 Antenna driver 1 output

5 VSS Power and digital ground

6 VDD Voltage regulator output

7 TD2 Antenna driver 2 output

8 MODE1 Mode selection input 1

9 MODE2 Mode selection input 2

10 RD Demodulator input

11 AGND Demodulator ground

12 CEXT Comparator reference input

MC33690

13 DOUT Demodulator output (5V)

14 LVR Low Voltage Reset input/output

15 XTAL2 Oscillator output

16 XTAL1 Oscillator input

17 AM Amplitude modulation input

18 K ISO 9141 transmitter output and receiver input

19 Rx ISO 9141 receiver monitor output

20 Tx ISO 9141 transmitter input

MOTOROLA SEMICONDUCTORS PRODUCTS

revision 4.8, 5 February 2002

DESCRIPTION

TAG READER MODULE

MC33690

The Tag Reader module is dedicated for automotive or industrial applications where information has to be transmitted contactless. The tag reader module is a write/read (challenge/ response) controller for applications which demand high security level.

The tag reader module is connected to a serial tuned LC circuit which generates a magnetic field power supplying the tag.

Figure 2 : Tag Reader block diagram

TD1

125kHz

1/32 counter 1/2

125kHz

Self synchronous

sample & hold

The use of a synchronous sample & hold technique allows communication with all avalaible tags using admittance switching producing absorption of the RF field. Load amplitude or phase shift modulation can be detected at high bit rates up to 8kHz. 125kHz is the typical operational carrier frequency of the tag reader module with a 8MHz clock.

AM Data

Clock 8MHz

4MHz

8MHz

Shutdown

Setup & Preload

LVR

TD2

VDD

11.25° , 22.5° , 33.75° , 45° , 56.25° , 67.5° , 78.75° , 90°

+ 0°, -11.25°, -22.5°, -33.75°, -45°, -56.25°, -67.5°, -78.75°

Buffer

500ns

S/H Buffer

AGND

100K

EXT

Comparator

Ω

VDD

CEXT

10nF

DCQ

500µA

Interface

Data out

MOTOROLA SEMICONDUCTORS PRODUCTS

revision 4.8, 5 February 2002

MC33690

Read function

When answering to the base station, a transponder generates an absorption modulation of the magnetic field. It results in an amplitude/ phase modulation of the current across the antenna. This information is picked up at the antenna tap point between the coil and the capacitor. An external resistive ladder down scales this voltage to a level compatible with the demodulator input voltage range (see parameter V

page 16).

INRD

The demodulator (see figure 2) consists of :

- an input stage (emitter follower),

- a sample & hold circuit,

- a voltage follower,

- a low offset voltage comparator. The sampling time is automatically set to take into account a phase shift due to the tolerances of the antenna components (L and C) and of the oscillator. The allowed phase shift measured at the input RD ranges from -45° to +45°. Assuming that the phase reference is the falling edge of the driving signal TD1, this leads to a sampling time phase ranging from -78.75° to 90° with discrete steps of 11.25°. After reset condition, the sampling time phase is +11.25°.

The antenna phase shift evaluation is only done :

- after each wake-up command (see pages

10 to 12),

- or after reset (see page 7). This is necessary to obtain the best demodulator performances. In order to ensure a fast demodulator settling time after wake up, reset or a write sequence, the external capacitor C

is preloaded at its

EXT

working voltage. This preset occurs 256µs after switching the antenna drivers on and its duration is 128µs. After wake up or reset, the preset has the same duration but begins 518µs after clock settling. After power on reset, VSUP must meet the minimum specified value, enabling the nominal operation of VDD, before the start of the preset. Otherwise the preset must be done by the user through a standby/wake-up sequence.

Write function

Whatever the selected configuration (see page 9), the write function is achieved by switching on/off the output drivers TD1/2. Once the drivers have been set in high impedance, the load current flows alternatively

Figure 3 : Current flow when the buffers are switched off

VDD

TD1

LOAD

TD2

VDD

MOTOROLA SEMICONDUCTORS PRODUCTS

revision 4.8, 5 February 2002

VOLTAGE REGULATOR

MC33690

The low dropout voltage regulator provides a regulated 5V supply for the internal circuitry. It can also supply external peripherals or sensors. The input supply voltage ranges from 5.5V to over 40V.

This voltage regulator uses a series combination of high voltage LDMOS and low voltage PMOS transistors to provide regulation. An external low ESR capacitor is required for the regulator stability.

The maximum average current is limited by the power dissipation capability of the SO 20 package. This limitation can be overcome by connecting an external N channel MOS in parallel with the

Figure 4 : Voltage regulator block diagram

VBAT

VSUP

internal LDMOS. The threshold voltage of this transistor must be lower than the one of the internal LDMOS (1.95V typ.) in order to prevent the current from flowing into the LDMOS. Its breakdown voltage must be higher than the maximum supply voltage.

A low voltage reset function monitors the VDD output. An internal 10µA pull-up current source allows, when an external capacitor is connected between LVR and GND, to generate delays at power up (5ms typ. with C

Reset

=22nF) . The LVR pin is also the input generating the internal reset signal. Applying a logic low level on this pin resets the circuit :

- all the internal flip flops are reset,

- the drivers TD1/2 are switched on.

GATE

Reset

LVR

VDD

10µA

1MHz oscillator

Voltage reference

and biasing

generator

VDD

reset

Comparator

Charge pump

N channel

LDMOS

SOURCE

P channel

MOS

VDD

10µF

100nF

VDD

MOTOROLA SEMICONDUCTORS PRODUCTS

revision 4.8, 5 February 2002

ISO 9141 PHYSICAL INTERFACE

MC33690

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 2k

Ω resistor (typ.) in series with a diode.

A current limitation allows the transmitter to drive

Figure 5 : ISO 9141interface

AM data

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).

The electromagnetic emission is reduced thanks to the voltage slew rate control (5V/µs typ.).

VDD

2kΩ

VSUP

L line

From configuration controller

VDD

From configuration controller

Tag Reader module output

VDD

VSUP

Over temperature

detector

Command

Current limitation

GND

2.5µA

GND

2kΩ

VBAT

GND

K line

MOTOROLA SEMICONDUCTORS PRODUCTS

revision 4.8, 5 February 2002

+ 16 hidden pages