MCP2030 Microchip Technology Inc., MCP2030 Datasheet - Page 27

• Manufacturer Part Number: MCP2030
• Description: Three-channel Analog Front-end Device
• Manufacturer: Microchip Technology Inc.

4.0
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 mV
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
transponder, an LF Initiator sensor for Tire Pressure
Monitoring Systems (TPMS) and long-range access
control applications in the automotive and security
industries.
FIGURE 4-1:
© 2005 Microchip Technology Inc.
V
Legend:
BAT
hands-free
APPLICATION INFORMATION
D
D
BLOCK
C
BLOCK
D
C
R
POOL
D
R
COM
FLAT
COM
LIM
LIM
Passive
= LCCOM charging capacitor.
= Pool capacitor (or battery back-up capacitor), charges in field and powers device.
= Battery protection from reverse charge.
= Field rectifier diodes.
= Voltage limiting diode, may be required to limit V
= LCCOM discharge path.
= Current limiting resistor, required for air coil in strong fields.
External Circuit Example for LF Field Powering and Battery Back-up Mode.
Schottky for low forward bias drop.
D
LIM
Keyless
V
DD
C
POOL
Entry
(PKE)
D
D
FLAT1
FLAT2
PP
)
Air Coil
L
X
4.1
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.
Note:
R
L
C
Y
COM
X
R
LIM
Battery Back-up and Batteryless
Operation
DD
Voltage on LCCOM combined with coil
input voltage must not exceed the maxi-
mum LC input voltage.
C
C
voltage when in strong fields.
COM
Y
L
Z
C
Z
LCCOM
MCP2030
LCX
LCY
LCZ
DS21981A-page 27