MCP2030-ISLASHST datasheet(27/66 Pages) MICROCHIP

27 / 66 page

DS21981A-page 27

MCP2030

4.0

APPLICATION INFORMATION

The MCP2030 is a stand-alone 3-channel analog

front-end device for low frequency (LF) sensing and

bidirectional transponder applications. By connecting

three orthogonally placed LC resonant antennas to

the LC input pins, it can detect signals from all

directions (x, y and z).

The device draws more current when all channels are

enabled as compared to a single channel; therefore, it

is recommended to disable any unused channels by

setting Configuration Register 0 (Register 5-1).

The device’s high input sensitivity (as low as 1 mVPP)

and ability to detect weakly modulated (as low as 8%)

input signals with its low power feature set, makes the

device suitable for various applications such as a low-

cost

hands-free

Passive

Keyless

Entry

(PKE)

transponder, an LF Initiator sensor for Tire Pressure

Monitoring Systems (TPMS) and long-range access

control applications in the automotive and security

industries.

4.1

Battery Back-up and Batteryless

Operation

The device supports both battery back-up and

batteryless operation by the addition of external

components, allowing the device to be partially or

completely powered from the field.

Figure 4-1 shows an example of the external circuit for

the battery back-up.

FIGURE 4-1:

External Circuit Example for LF Field Powering and Battery Back-up Mode.

Note:

Voltage on LCCOM combined with coil

input voltage must not exceed the maxi-

mum LC input voltage.

LCX

LCY

LCZ

VBAT

DBLOCK

CPOOL

DFLAT1

RLIM

LCCOM

CCOM

Air Coil

DFLAT2

VDD

RCOM

DLIM

Legend:

CCOM = LCCOM charging capacitor.

CPOOL = Pool capacitor (or battery back-up capacitor), charges in field and powers device.

DBLOCK = Battery protection from reverse charge.

Schottky for low forward bias drop.

DFLAT = Field rectifier diodes.

DLIM = Voltage limiting diode, may be required to limit VDD voltage when in strong fields.

RCOM = LCCOM discharge path.

RLIM = Current limiting resistor, required for air coil in strong fields.

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