Variable Split Band Inverter

5

MX214/224

1998 MX-COM, Inc.

www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054

Doc. # 20480112.002

4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA

All trademarks and service marks are held by their respective companies.

MX214

Pin No.

MX224

Pin No.

Signal Name

Description

J/P

LH

J/P

LH

15

11

11

11

Latch

/

Load

This pin controls the loading of the 8 digital function

inputs (ENABLE, CLEAR, A0-A4) into the internal

register. When this pin is at a logic ‘1’, all eight

inputs are transparent and new data acts directly.

For controlled changing of parameters in the

parallel,

Latch

/

Load

must be kept at logic ‘0’ while

a new function is loaded, then strobed 0-1-0 to latch

the inputs in. For serial loading, the serial data

should be loaded with the

Latch

/

Load

at logic ‘0’

and then the

Latch

/

Load

strobed 0-1-0 on

completion of data loading. Internal 1M

 pull-up

resistor (Load). See Figure 8.

16

12

12

12

Powersave

This digital input is used to place the MX214/224

into Powersave mode where all parts of the device

except the 1MHz oscillator are shut down. All signal

input and output lines are made open circuit, free of

all bias. This allows signal paths to be routed

externally around the device, while reducing current

consumption. A logic ‘0’ at this input enables the

device to work normally as shown in Table 2.

Internal 1M

 pull-up resistor.

17

13

13

13

Negative supply (GND)

18

14

14

14

Internal connection

This pin is internally connected. Leave open circuit.

19

15

15

15

Rx Output

This is the processed received audio signal output.

This pin is held at a DC ‘bias’ voltage for all

functions except Powersave. This buffered output is

driven by the summing circuit in the Rx mode.

Signal paths and bias levels are detailed in Table 2

and Figure 7.

20

16

16

16

Tx Output

This is the processed audio output for the

transmission channel. This pin is held at a DC ‘bias’

voltage for all functions except Powersave. This

summed and buffered signal is passed through the

CTCSS high pass Filter to the output pin in the Tx

Mode. Signal paths and bias levels are detailed in

Table 2 and Figure 6.

21

17

17

17

22

18

18

18

Rx Input

This is the analog received signal input. This pin is

held at a DC ‘bias’ voltage by a 300k

 on-chip bias

resistor, which is selected for all functions except

Powersave. It must be connected to external

circuitry by capacitor C3. See Figure 2 and Figure

3. This input is routed through the CTCSS High

Pass Filter in Rx mode to remove subaudio

frequencies from the voiceband. Signal paths and

bias levels are detailed in Table 2 and Figure 7.

1

19

19

19

Highband Filter

Output

The output of the Input Filter of the Upperband limit.

The

Tx

/

Rx

functions sets the lowpass filter at

3400Hz or 2700Hz respectively. This output must

be connected to the Highband Balanced modulator

input via capacitor C5. See Figure 2 and Figure 3.