EM4150 datasheet(9/14 Pages) EMMICRO

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EM4150

EM4350

Power On Reset (POR)

When the EM4150 with its attached coil enters an

electromagnetic field, the built in AC/DC converter will

supply the chip. The DC voltage is monitored and a

Reset signal is generated to initialise the logic. The

contents of the Control word and Protection word will be

downloaded to enable the functions (INIT). The Power

On Reset is also provided in order to make sure that the

chip will start issuing correct data. Hysteresis is provided

to avoid improper operation at the limit level.

VDD

Reset

EM4150 Active

tinit

prh

prhys

Fig. 18

Lock All / Lock Memory Area

The EM4150 can be converted to a Read Only chip or be

configured to Read/Write and Read Only Areas by

programming the protection word. This configuration can

be locked by write inhibiting the Write Protection Word.

Great care should be taken in doing this operation as

there is no further possibility to change the Write

Protection Word. The Control Word can also be

protected in the same way thus freezing the operation

mode.

Clock Extractor

The Clock extractor will generate a system clock with a

frequency corresponding to the frequency of the RF field.

The system clock is used by a sequencer to generate all

internal timings.

Data Extractor

The transceiver generated field will be amplitude

modulated to transmit data to the EM4150. The Data

extractor demodulates the incoming signal to generate

logic levels, and decodes the incoming data.

Modulator

The Data Modulator is driven by the serial data output

from the memory which is Manchester encoded. The

modulator will draw a large current from both coil

terminals, thus amplitude modulating the RF field

according to the memory data.

AC/DC Converter and Voltage Limiter

The AC/DC converter is fully integrated on chip and will

extract the power from the incident RF field. The internal

DC voltage will be clamped to avoid high internal DC

voltage in strong RF fields.

Resonance Capacitor

The Resonance Capacitor is integrated, and its tolerance

is adjusted to ± 2% over the whole production.

Typical Capacitor Variation

versus Temperature

Temperature [°C]

99.7

99.8

99.9

100.0

100.1

100.2

100.3

-50

-30

-10

Cr Tolerance [%]

Fig. 19

Special Timings

The Processing Pause Time (tpp), Write Access Time

(twa) and EEPROM Write Time (Twee) are timings

where the EM4150 is executing internal operations.

During these pauses, the RF field will be influenced.

During Twa and Twee, the signal on the coil is

damped due to a higher current consumption.

32 32

RF periods :

tpp

Same modulation

as for a normal bit

16 16

(Opt64)

(Opt32)

(Opt64)

(Opt32)

twa

3200

2624

(Opt64)

(Opt32)

twee

Fig. 20

EM4150 Datasheet(PDF) 9 Page - EM Microelectronic - MARIN SA

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