MX614P - MX-COM, Inc. - Product.Network

COMMUNICATION SEMICONDUCTORS

MX614

DATA BULLETIN Bell 202 Compatible Modem





2000 MX-COM, INC. www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054 Doc. # 20480162.004

4800 Bethania Station Road, Winston-Salem, NC 27105 USA All Trademarks and Service Marks are held by their respective companies.

PRELIMINARY INFORMATION

Features Applications

• 1200bps - 1800bps half duplex Bell 202

Compatible Modem

• Optional 1200bps Data Retiming Facility

can eliminate external UART

• Optional 5bps and 150bps Back Channel

• Optional Line Equalization

• Low Voltage Operation (3.3V to 5.0V)

• Low Power Operation

1mA typ. @ 3.3V Operating Mode

1µ

µµ

µA typ. Zero-Power Mode

• Standard 3.58MHz Xtal/Clock

• Telephone Telemetry Applications

µC

Data

Control

Status

MX614

Line

Interface

Telephone

Line

The MX614 is a low voltage, low power CMOS integrated circuit designed for the reception or transmission of

asynchronous 1200bps data. This device is compatible with Bell 202 type systems. The MX614 supports

5bps and 150bps 'back channel' operation. Asynchronous data rates up to 1818bps are also supported.

The MX614 provides an optional Tx and Rx data retiming function which can eliminate, based on user

preference, the need for a UART in the associated µC when operating at 1200bps. An optional line equalizer

has been incorporated into the receive path and is controlled by an external logic level.

The MX614 may be used in a wide range of telephone telemetry systems. A very low current “Zero Power

Mode (1µA typ.) and an operating current of 1mA typ. @ VDD = 3.3V, make the MX614 ideal for portable,

terminal and line powered applications. A standard 3.58MHz Xtal/Clock is required and the device operates

from a 3.0V to 5.5V supply.

The MX614 is available in 24-pin TSSOP (MX614TN), 16-pin SOIC (MX614DW) and 16-pin PDIP (MX614P)

packages.

Bell 202 Compatible Modem 2 MX614 PRELIMINARY INFORMATION





2000 MX-COM, INC. www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054 Doc. # 20480162.004

4800 Bethania Station Road, Winston-Salem, NC 27105 USA All Trademarks and Service Marks are held by their respective companies.

CONTENTS

Section Page

1. Block Diagram................................................................................................................. 3

2. Signal List........................................................................................................................ 4

3. External Components ..................................................................................................... 5

4. General Description ........................................................................................................ 6

4.1 Xtal Osc and Clock Dividers....................................................................................................6

4.2 Mode Control Logic.................................................................................................................6

4.3 Rx Input Amplifier....................................................................................................................6

4.4 Receive Filter and Equalizer ...................................................................................................6

4.5 Energy Detector ......................................................................................................................7

4.6 FSK Demodulator....................................................................................................................7

4.7 FSK Modulator and Transmit Filter .........................................................................................8

4.8 Rx Data Retiming....................................................................................................................9

4.9 Tx Data Retiming ..................................................................................................................10

5. Application Notes.......................................................................................................... 12

5.1 Line Interface ........................................................................................................................12

6. Performance Specification........................................................................................... 13

6.1 Electrical Performance ..........................................................................................................13

6.2 Packaging .............................................................................................................................16

MX•COM, Inc. reserves the right to change specifications at any time and without notice.

Bell 202 Compatible Modem 3 MX614 PRELIMINARY INFORMATION





2000 MX-COM, INC. www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054 Doc. # 20480162.004

4800 Bethania Station Road, Winston-Salem, NC 27105 USA All Trademarks and Service Marks are held by their respective companies.

1. Block Diagram

TXD

RXEQ

CLK

RXD

RDY

DET

Energy

Detect

FSK

De-modulator

Receive

Filter and

Equalizer

Mode

Control

Logic

Rx/Tx Data

Re-timing

Transmit Filter

and Output Buffer

FSK

Modulator

RXIN

RXAMPOUT

TXOUT

Xtal Osc and

Clock Dividers

XTAL/

CLOCK

XTAL

BIAS

Figure 1: Block Diagram

Bell 202 Compatible Modem 4 MX614 PRELIMINARY INFORMATION





2000 MX-COM, INC. www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054 Doc. # 20480162.004

4800 Bethania Station Road, Winston-Salem, NC 27105 USA All Trademarks and Service Marks are held by their respective companies.

2. Signal List

Pin No. Signal Description

P, DW TN Name Type

11 XTAL output Output of the on-chip Xtal oscillator inverter.

2 2 XTAL/CLOCK input Input to the on-chip Xtal oscillator inverter.

3 5 M0 input A logic level input for setting the mode of the device. See

section 4.2

4 6 M1 input A logic level input for setting the mode of the device. See

section 4.2

5 7 RXIN input Input to the Rx input amplifier.

6 8 RXAMPOUT output Output of the Rx input amplifier

7 11 TXOUT output Output of the FSK generator.

812 V

SS Power Negative supply (ground).

913 V

BIAS output Internally generated bias voltage, held at VDD/2 when the

device is not in 'Zero-Power' mode. Should be bypassed to

VSS by a capacitor mounted close to the device pins.

10 14 RXEQinput A logic level input for enabling/disabling the equalizer in the

receive filter. See section 4.4

11 17 TXD input A logic level input for either the raw input to the FSK

Modulator or data to be re-timed depending on the state of

the M0, M1 and CLK inputs. See section 4.9

12 18 CLK input A logic level input which may be used to clock data bits in or

out of the FSK Data Retiming block.

13 19 RXD output A logic level output carrying either the raw output of the FSK

Demodulator or re-timed characters depending on the state of

the M0, M1 and CLK inputs. See section 4.8

14 20 DET output A logic level output of the on-chip Energy Detect circuit.

15 23 RDYoutput "Ready for data transfer"output of the on-chip data retiming

circuit. This open-drain active low output may be used as an

Interrupt Request/Wake-up input to the associated µC. An

external pull-up resistor should be connected between this

output and VDD.

16 24 VDD Power Positive supply. Levels and thresholds within the device are

proportional to this voltage. Should be bypassed to VSS by a

capacitor mounted close to the device pins.

3, 4,

9, 10,

15,

16,

21,

N/C No internal connection

Bell 202 Compatible Modem 5 MX614 PRELIMINARY INFORMATION

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2000 MX-COM, INC. www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054 Doc. # 20480162.004

4800 Bethania Station Road, Winston-Salem, NC 27105 USA All Trademarks and Service Marks are held by their respective companies.

3. External Components

BIAS

MX614

DET

RDY

CLK

RXEQ

RXD

TXD

TXOUT

RXAMPOUT

RXIN

To / Fr o m µ C

From µC

X1 R1

XTAL/CLOCK

XTAL

R1 100kΩ±5%

C1 C2 18pF ±10%

C3 0.1µF±10%

C4 0.1µF±10%

X1 Note 1 3.579545MHz

Figure 2: Recommended External Components for Typical Application

External Components Notes

1. IMPORTANT: This device is capable of detecting and decoding small amplitude signals. To achieve

this VDD and VBIAS decoupling and protecting the receive path from extraneous in-band signals are very

important. It is recommended that the decoupling capacitors be placed so that connections between

them and the device pins are as short as practicable e.g. ≤ 1 inch from device pins. A ground plane

protecting the receive path will help attenuate interfering signals

2. A crystal frequency of 3.579545MHz ±0.1%is required for correct FSK operation. For best results, a

crystal oscillator design should drive the clock inverter input with signal levels of at least 40%of VDD

peak-peak. Tuning fork crystals generally cannot meet this requirement. To obtain crystal oscillator

design assistance, consult your crystal manufacturer.

Bell 202 Compatible Modem 6 MX614 PRELIMINARY INFORMATION





2000 MX-COM, INC. www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054 Doc. # 20480162.004

4800 Bethania Station Road, Winston-Salem, NC 27105 USA All Trademarks and Service Marks are held by their respective companies.

4. General Description

4.1 Xtal Osc and Clock Dividers

Frequency and timing accuracy of the MX614 is determined by a 3.579545MHz clock signal present at the

XTAL/CLOCK pin. This may be generated by the on-chip oscillator inverter using the external components

C1, C2 and X1 of Figure 2, or may be supplied from an external source to the XTAL/CLOCK input. If supplied

from an external source, C1, C2 and X1 should not be fitted.

The on-chip oscillator is turned off in the 'Zero-Power' mode.

If the clock is provided by an external source which is not always running, then the 'Zero-Power' mode must

be set when the clock is not available. Failure to observe this rule may cause a significant rise in the supply

current drawn by MX614 as well as generating undefined states of the RXD, DET and RDYoutputs.

4.2 Mode Control Logic

The MX614's operating mode is determined by the logic levels applied to the M0 and M1 input pins:

M1 M0 Rx Mode Tx Mode Data Retime[1]

0 0 1200bps 150bps Rx

0 1 Off 1200bps Tx

1 0 1200bps Off / 5bps Rx

11 'Zero-Power' -

[1]If enabled

Note: On applying power to the device, the mode must be set to 'ZP', i.e. M0 = '1', M1 = '1', until VDD

has stabilized.

In the 'Zero-Power' (ZP) mode, power is removed from all internal circuitry. When leaving the 'ZP' mode there

must be a delay of 20ms before any Tx data is passed to, or Rx data read from the device to allow the bias

level, filters, and oscillator to stabilize.

4.3 Rx Input Amplifier

This amplifier is used to adjust the received signal to the correct amplitude for the FSK receiver and Energy

Detect circuits (see section 5.1).

4.4 Receive Filter and Equalizer

The Receive Filter and Equalizer section is used to attenuate out of band noise and interfering signals,

especially the locally generated transmit tones which might otherwise reach the 1200bps FSK Demodulator

and Energy Detector circuits. This block also includes a switchable equalizer section. When the RXEQpin is

low, the overall group delay of the receive filter is flat over the 1200bps frequency range. If the RXEQpin is

high the receive filter's typical overall group delay will be as shown in Figure 3.

Bell 202 Compatible Modem 7 MX614 PRELIMINARY INFORMATION

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

2000 MX-COM, INC. www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054 Doc. # 20480162.004

4800 Bethania Station Road, Winston-Salem, NC 27105 USA All Trademarks and Service Marks are held by their respective companies.

-0.15

-0.125

-0.1

-0.075

-0.05

-0.025

0.025

500 1000 1500 2000 2500

Delay/ms

Frequency/Hz

Figure 3: Rx Equalizer Group Delay (RXEQ = '1') wrt 1700Hz

4.5 Energy Detector

This block operates by measuring the level of the signal at the output of the Receive Filter, and comparing it

against a preset threshold.

The DET output will be set high when the level has exceeded the threshold for a sufficient period of time.

Amplitude and time hysteresis are used to reduce chattering of the DET output in marginal conditions.

Note that this circuit may also respond to non-FSK signals such as speech.

DET

Line Signal

M0, M1 FSK Receive mode

FSK signal

TeOFF

See section 6.1 for definitions of TeON and TeOFF

Figure 4: FSK Level Detector Operation

4.6 FSK Demodulator

This block converts the 1200bps FSK input signal to a logic level received data signal which is output via the

RXD pin as long as the Data Retiming function is not enabled (see section 4.8). This output does not depend

on the state of the DET output.

When the Rx 1200bps mode is 'Off' or in 'ZP' the DET and RXD pins are held low.

Note that in the absence of a valid FSK signal, the demodulator may falsely interpret speech or other

extraneous signals as data. For this reason it is advised that the RXD pin is read only when data is expected.

Bell 202 Compatible Modem 8 MX614 PRELIMINARY INFORMATION





2000 MX-COM, INC. www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054 Doc. # 20480162.004

4800 Bethania Station Road, Winston-Salem, NC 27105 USA All Trademarks and Service Marks are held by their respective companies.

4.7 FSK Modulator and Transmit Filter

These blocks produce a tone according to the TXD, M0 and M1 inputs as shown in the table below, assuming

data retiming is not being used:

M1 M0 TXD = 0 TXD = 1

11 - -

100Hz[1]387Hz

0 0 487Hz 387Hz

0 1 2200Hz 1200Hz

Note:[1]TXOUT held at approx. VDD/2.

When modulated at the appropriate baud rates, the Transmit Filter and associated external components (see

section 5.1) limit the FSK out of band energy sent to the line in accordance with Figure 5 and Figure 6,

assuming that the signal on the line is at -6dBm or less.

-70

-60

-50

-40

-30

-20

-10

10 100 1000 10000 100000

Frequency / Hz

dBm

1300 Hz

3400 Hz

28 kHz

250 Hz

Figure 5: Tx limits at 5bps and 150bps rate

Bell 202 Compatible Modem 9 MX614 PRELIMINARY INFORMATION

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2000 MX-COM, INC. www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054 Doc. # 20480162.004

4800 Bethania Station Road, Winston-Salem, NC 27105 USA All Trademarks and Service Marks are held by their respective companies.

-70

-60

-50

-40

-30

-20

-10

10 100 1000 10000 100000

Frequency / Hz

dBm

3400 Hz

28 kHz

450 Hz

Figure 6: Tx limits at 1200bps rate

4.8 Rx Data Retiming

This function may be used when the received data consists of 1200bps asynchronous characters, each

character consisting of one start bit followed by a minimum of 9 formatted bits as shown in the table below.

Note: Rx Data Retiming is not supported for data rates exceeding 1212bps.

Data bits Parity bits Stop bits

≥2

≥1

The Data Retiming block, when enabled in receive mode, extracts the first 9 bits of each character following

the start bit from the received asynchronous data stream, and presents them to the µC under the control of

strobe pulses applied to the CLK input. The timing of these pulses is not critical and they may easily be

generated by a simple software loop. This facility removes the need for a UART in the µC without incurring

an excessive software overhead.

The receive retiming block consists of two 9-bit shift registers, the input of the first is connected to the output

of the FSK demodulator and the output of the second is connected to the RXD pin. The first register is

clocked by an internally generated signal that stores the 9 received bits following the timing reference of a

high to low transition at the output of the FSK demodulator. When the 9th bit is clocked into the first register

these 9 bits are transferred to the second register, a new stop-start search is initiated and the CLK input is

sampled. If the CLK input is low at this time the RDYpin is pulled low and the first received bit is output on

the RXD pin. The CLK pin should then be pulsed high 9 times, the first 8 high to low transitions will be used

by the device to clock out the bits in the second register. The RDYoutput is cleared the first time the CLK

input goes high. At the end of the 9th pulse the RXD pin will be connected to the FSK demodulator output.

So to use the Data Retiming function, the CLK input should be kept low until the RDYoutput goes low;if the

Data Retiming function is not required the CLK input should be kept high at all times.

Bell 202 Compatible Modem 10 MX614 PRELIMINARY INFORMATION

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

2000 MX-COM, INC. www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054 Doc. # 20480162.004

4800 Bethania Station Road, Winston-Salem, NC 27105 USA All Trademarks and Service Marks are held by their respective companies.

The only restrictions on the timing of the CLK waveform are those shown in Figure 7 and the need to

complete the transfer of all nine bits into the µC within the time of a complete character at 1200bps. See

Section 6.2 for Timing specifications.

START STOP1

23456789

FSK Demod output :

RDY output :

RXCK input :

RXD output :

Received Character 'n'

Retimed data bits from

received character 'n'

Data Bit 1 Data Bit 2

tDtcHI

tcLO

RXCK

RXD

9 Bits of data

RDY

tD= Internal MX614 delay, tcHI = CLK high time, tcLO = CLK low time

Figure 7: FSK Operation with Rx Data Retiming

Note that, if enabled, the Data Retiming block may interpret speech or other signals as random characters.

If the Data Retiming facility is not required, the CLK input to the MX614 should be kept high at all times. The

asynchronous data from the FSK Demodulator will then be connected directly to the RXD output pin, and the

RDYoutput will not be activated by the FSK signal. This case is illustrated by the example in Figure 8.

START

STOP

FSK Demod output :

RXD output :

Received Character 'n'

Figure 8: FSK Operation without Rx Data Retiming (CLK always high)

4.9 Tx Data Retiming

The Data Retiming block, when enabled in 1200bps transmit mode, requires the controlling µC to load one bit

at a time into the device by a pulse applied to the CLK input. The timing of this pulse is not critical and it may

easily be generated by a simple software loop. This facility removes the need for a UART in the µC without

incurring an excessive software overhead. Note: Tx Data Retiming is not supported for data rates

exceeding 1212bps.

The Tx re-timing circuit consists of two 1-bit registers in series, the input of the first is connected to the TXD

pin and the output of the second feeds the FSK modulator. The second register is clocked by an internally

generated 1200Hz signal and when this occurs the CLK input is sampled. If the CLK input is high the TXD

pin directly controls the FSK modulator, if the CLK input is low the FSK modulator is controlled by the output

of the second register and the RDYpin is pulled low. The RDYoutput is reset by a high level on the CLK

input pin. A low to high change on the CLK input pin will latch the data from the TXD input pin into the first

So to use the retiming option the CLK input should be held low until the RDYoutput is pulled low. When the

RDYpin goes low the next data bit should be applied at the TXD input and the CLK input pulled high and then

low within the time limits set out in Figure 9. See Section 6.2 for Timing specifications.

Bell 202 Compatible Modem 11 MX614 PRELIMINARY INFORMATION

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2000 MX-COM, INC. www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054 Doc. # 20480162.004

4800 Bethania Station Road, Winston-Salem, NC 27105 USA All Trademarks and Service Marks are held by their respective companies.

234

FSK Modulator input :

CLK input :

TXD input :

RDY

CLK

TXD

RDY output :

tD= Internal MX614 delay, tR=RDYlow to CLK going low, tS= data set up time

tcHI= CLK high time, tH= data hold time

Figure 9: FSK Operation with Tx Data Retiming

To ensure synchronization between the controlling device and the MX614 when entering Tx retiming mode

the TXD pin must be held at a constant logic level from when the CLK pin is first pulled low to the end of

loading in the second retimed bit. Similarly when exiting Tx retiming mode the TXD pin should be held at the

same logic level as the last retimed bit for at least 2 bit times after the CLK line is pulled high.

If the data retiming facility is not required, the CLK input to the MX614 should be kept high at all times. The

asynchronous data to the FSK modulator will then be connected directly to the TXD input pin. This is

illustrated in Figure 10 and will also be the case when transmitting 5bps or 150bps data which has no retime

option.

N-2

N-1

N+1

N+2

FSK Modulator input :

TXD input :

Figure 10: FSK Operation without Tx Data Retiming (CLK always high)

Bell 202 Compatible Modem 12 MX614 PRELIMINARY INFORMATION

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

2000 MX-COM, INC. www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054 Doc. # 20480162.004

4800 Bethania Station Road, Winston-Salem, NC 27105 USA All Trademarks and Service Marks are held by their respective companies.

5. Application

5.1 Line Interface

The signals on the telephone line are not suitable for direct connection to the MX614. A Line Interface circuit

is required to:

•Provide high voltage and dc isolation

•Attenuate the Tx signal present at the Rx input

•Provide the low impedance drive necessary for the line

•Filter the Tx and Rx signals

LINE

1:1

R5R4

RXIN

RXAMPOUT

TXOUT

BIAS

R2 See Notes ±1%,

R3 See Notes ±1%,

R4-R7 100kΩ±1%,

C5 22µF±20%

C6 100pF ±10%

C7 330pF ±10%

Figure 11: Line Interface Circuit

Bell 202 Compatible Modem 13 MX614 PRELIMINARY INFORMATION





2000 MX-COM, INC. www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054 Doc. # 20480162.004

4800 Bethania Station Road, Winston-Salem, NC 27105 USA All Trademarks and Service Marks are held by their respective companies.

Line Interface Notes:

1. The components 'Z' between points B and C should match the line impedance.

2. Device A2 must be able to drive 'Z' and the line.

3. R2:For optimum results R2 should be set so that the gain is VDD/5.0, i.e. R2 = 100kΩat VDD =5.0V,rising

to 150kΩat VDD =3.3V.

4. R3:The levels in dB (relative to a 775mVRMS signal) at 'A', 'B' and 'C' in the line interface circuit are:

Level at 'A' = 20Log(VDD/5)

"'B' = 'A' +20Log(100kΩ/R3)

"'C' = 'B' - 6

Example:

VDD 'A' R3 'B' 'C'

3.3V -3.6dB 100kΩ-3.6dB -9.6dB

5.0V 0dB 150kΩ-3.5dB -9.5dB

6. Performance Specification

6.1 Electrical Performance

Absolute Maximum Ratings

Exceeding these maximum ratings can result in damage to the device.

General Min. Max. Units

Supply (VDD -V

SS)-0.3 7.0 V

Voltage on any pin to VSS -0.3 VDD +0.3 V

Current into or out of and pins

VDD -30 30 mA

VSS -30 30 mA

Any other pins -20 20 mA

DW / PDIP Packages

Total Allowable Power Dissipation at TAMB = 25°C 800 mW

Derating above 25°C 13 mW/°C above 25°C

Storage Temperature -55 125 °C

Operating Temperature -40 85 °C

Operating Limits

Correct operation of the device outside these limits is not implied.

Notes Min. Max. Units

Supply (VDD -V

SS)3.05.5V

Operating Temperature -40 85 °C

Xtal Frequency 1 3.575965 3.583125 MHz

Operating Limits Notes:

1. A crystal frequency of 3.579545MHz ±0.1%is required for correct FSK operation.

Bell 202 Compatible Modem 14 MX614 PRELIMINARY INFORMATION

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

2000 MX-COM, INC. www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054 Doc. # 20480162.004

4800 Bethania Station Road, Winston-Salem, NC 27105 USA All Trademarks and Service Marks are held by their respective companies.

Operating Characteristics

For the following conditions unless otherwise specified:

VDD =3.3VatT

AMB = 25°C

Xtal Frequency = 3.579545MHz ±0.1%0dBV corresponds to 1.0VRMS

Tx and Rx data rates = 1200bps.

Notes Min. Typ. Max. Units

DC Parameters

IDD (M0 = '1', M1 = '1') 1, 2 1.0 µA

IDD (M0orM1='0')atV

DD = 3.0V 1 1.0 1.25 mA

IDD (M0orM1='0')atV

DD = 5.0V 1 1.7 2.5 mA

Logic '1' Input Level 70%VDD

Logic '0' Input Level 30%VDD

Logic Input Leakage Current (VIN =0toV

DD), Excluding

XTAL/CLOCK Input

-1.0 1.0 µA

Output Logic '1' Level (lOH = 360µA) VDD -0.4 V

Output Logic '0' Level (lOL= 360µA) 0.4 V

RDYOutput 'off' State Current (VOUT =V

DD)1.0 µA

FSK Demodulator

Bit Rate 3 0 1200 1818 Baud

Mark (Logical '1') Frequency 1188 1200 1212 Hz

Space (Logical '0') Frequency 2178 2200 2222 Hz

Valid Input Level Range 4, 5 -40.0 -8.0 dBV

Maximum Twist (Mark Level wrt Space Level) ±6.0 dB

Acceptable Signal to Noise Ratio 6 20.0 dB

Level Detector 'On' Threshold Level 4 -40.0 dBV

Level Detector 'Off' to 'On' Time (Figure 4 TeON) 25.0 ms

Level Detector 'On' to 'Off' Time (Figure 4 TeOFF)8.0ms

FSK Retiming

Acceptable Rx Data Rate 1188 1200 1212 Baud

Tx Data Rate 1194 1206 Baud

FSK Modulator

TXOUT Level Driving ≥40kΩload 7 -3.2 -2.2 -1.2 dBV

Twist (Mark Level wrt Space Level) -2.0 0 2.0 dB

Tx 1200bps (M1 = '0', M0 = '1').

Bit Rate 3 0 1200 1818 Baud

Mark (Logical '1') Frequency 1197 1203 Hz

Space (Logical '0') Frequency 2196 2204 Hz

Tx 150bps (M1 = '0', M0 = '0').

Bit Rate 0 150 152 Baud

Mark (Logical '1') Frequency 385 389 Hz

Space (Logical '0') Frequency 485 489 Hz

Tx 5bps (M1 = '1', M0 = '0').

Bit Rate 0 5.0 5.1 Baud

Mark (Logical '1') Frequency 385 389 Hz

Bell 202 Compatible Modem 15 MX614 PRELIMINARY INFORMATION

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

2000 MX-COM, INC. www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054 Doc. # 20480162.004

4800 Bethania Station Road, Winston-Salem, NC 27105 USA All Trademarks and Service Marks are held by their respective companies.

Notes Min. Typ. Max. Units

Space (Logical '0') Frequency 8 0 Hz

Input Amplifier

Impedance (RXIN Pin) 9 10.0 MΩ

Voltage Gain 9 500 V/V

XTAL/CLOCK Input

'High' Pulse Width 10 100 ns

'Low' Pulse Width 10 100 ns

Operating Characteristics Notes:

1. Not including any current drawn from the MX614 pins by external circuitry other than X1, C1 and C2.

2. TXD, RXEQand CLK inputs at VSS, M0 and M1 inputs at VDD.

3. Tested at 1200bps.

4. Measured at the Rx Input Amplifier output (pin RXAMPOUT) for 1200Hz and VDD= 5.0V. The internal

threshold levels are proportional to VDD. To cater for other supply voltages or different signal level ranges

the voltage gain of the Rx Input Amplifier should be adjusted by selecting the appropriate external

components as described in section 5.1.

5. Best 1818bps performance is achieved when the minimum Input Level is _-32dBV.

6. Flat noise in 200 - 3200Hz band.

7. At VDD= 5.0V. (-2.2dBV is equivalent to 0dBm ref. 775mVRMS into 600Ω.)

8. TXOUT held at approximately VDD/2.

9. Open loop, small signal low frequency measurements.

10. Timing for an external input to the XTAL/CLOCK pin.

Bell 202 Compatible Modem 16 MX614 PRELIMINARY INFORMATION





2000 MX-COM, INC. www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054 Doc. # 20480162.004

4800 Bethania Station Road, Winston-Salem, NC 27105 USA All Trademarks and Service Marks are held by their respective companies.

6.2 Timing

Data and Mode Timing Notes Min. Typ. Max. Units

Rx Data Delay (RXIN to RXD) 1, 5 2.55 ms

Tx Delay Data (TXD to TXOUT) 1, 6 0.1 ms

Mode change delay ZP to Tx or Rx 2 20 ms

Mode change delay Tx1200 to Rx1200 2 4.0 ms

Mode change delay Rx1200 to Tx1200 2 0.2 ms

tD= Internal MX614 delay 3, 4 1 µs

tcHI = CLK High time 3, 4 1 µs

tcLO = CLK low time 3 1 µs

tR= RDYlow to CLK going low 4 800 µs

tS= Data Set-up time 4 1 µs

tH= Data Hold time 4 1 µs

Timing Notes

1. When data retiming is not enabled.

2. Delay from mode change to reliable data at TXOUT or RXD pins.

3. Reference Figure 7.

4. Reference Figure 9.

5. Reference Figure 12.

6. Reference Figure 13.

Valid 1 or 0

RXD

RXIN (FSK Signal)

Rx Data Delay

Note:M0 and M1 are preset and stable.

Figure 12: RXIN to RXD Delay time

TXD

TXOUT (FSK Signal)

Tx Data Delay

Note:M0 and M1 are preset and stable. FLO and FHI are the two FSK signaling frequencies.

Figure 13: TXD to TXOUT Delay time

Bell 202 Compatible Modem 17 MX614 PRELIMINARY INFORMATION





2000 MX-COM, INC. www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054 Doc. # 20480162.004

4800 Bethania Station Road, Winston-Salem, NC 27105 USA All Trademarks and Service Marks are held by their respective companies.

6.3 Packaging

PIN 1

ALTERNATIVE

LOCATION

MARKING

NOTE : All dimensions in inches (mm.)

Angles are in degrees

Package Tolerances

TYP. MAX.MIN.

DIM.

0.105 (2.67)0.093 (2.36)

0.419 (10.64)

45°

7°

0°10°

0.050 (1.27)

0.041 (1.04)

0.413 (10.49)

0.299 (7.59)

0.050 (1.27)

0.016 (0.41)

0.390 (9.90)

0.020 (0.51)0.003 (0.08)

0.009 (0.23) 0.0125 (0.32)

0.013 (0.33) 0.020 (0.51)

0.395 (10.03)

0.286 (7.26)

5°

Figure 14: 16-pin SOIC Mechanical Outline:

Order as part no. MX614DW

Package Tolerances

NOTE : All dimensions in inches (mm.)

Angles are in degrees

TYP. MAX.MIN.

DIM.

0.200 (5.06)

0.262 (6.63)

0.390 (9.91).

7°

0.150 (3.81)

0.810 (20.57)

0.135 (3.43)

0.100 (2.54)

0.121 (3.07)

0.300 (7.62)

0.290 (7.37) 0.325 (8.26)

0.015 (0.38) 0.070 (1.77)

0.008 (0.20) 0.015 (0.38)

0.014 (0.35) 0.023 (0.58)

0.040 (1.02) 0.065 (1.65)

0.056 (1.42) 0.064 (1.63)

0.740 (18.80)

0.240 (6.10)

PIN 1

Figure 15: 16-pin PDIP Mechanical Outline:

Order as part no. MX614P

Bell 202 Compatible Modem 18 MX614 PRELIMINARY INFORMATION





2000 MX-COM, INC. www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054 Doc. # 20480162.004

4800 Bethania Station Road, Winston-Salem, NC 27105 USA All Trademarks and Service Marks are held by their respective companies.

PIN 1

ALTERNATIVE

LOCATION

MARKING

0.303 (7.70)

Package Tolerances

TYP. MAX.MIN.

DIM.

0.047 (1.20)----------

0.256 (6.50)

0°8°

0.030 (0.75)

0.311 (7.90)

0.177 (4.50)

0.0256 (0.65)

0.020 (0.50)

0.248 (6.30)

0.006 (0.15)0.002 (0.05)

0.003 (0.08) 0.008 (0.20)

0.007 (0.17) 0.012 (0.30)

0.169 (4.30)

NOTE : All dimensions in inches (mm.)

Angles are in degrees

Figure 16 : 24-pin TSSOP Mechanical Outline:

Order as part no. MX614TN

CML Product Data

In the process of creating a more global image, the three standard product semiconductor

companies of CML Microsystems Plc (Consumer Microcircuits Limited (UK), MX-COM, Inc

(USA) and CML Microcircuits (Singapore) Pte Ltd) have undergone name changes and, whilst

maintaining their separate new names (CML Microcircuits (UK) Ltd, CML Microcircuits (USA)

Inc and CML Microcircuits (Singapore) Pte Ltd), now operate under the single title CML

Microcircuits.

These companies are all 100% owned operating companies of the CML Microsystems Plc

Group and these changes are purely changes of name and do not change any underlying legal

entities and hence will have no effect on any agreements or contacts currently in force.

CML Microcircuits Product Prefix Codes

Until the latter part of 1996, the differentiator between products manufactured and sold from

MXCOM, Inc. and Consumer Microcircuits Limited were denoted by the prefixes MX and FX

respectively. These products use the same silicon etc. and today still carry the same prefixes.

In the latter part of 1996, both companies adopted the common prefix: CMX.

This notification is relevant product information to which it is attached.

CML Microcircuits (USA) [formerly MX-COM, Inc.] Product Textual Marking

On CML Microcircuits (USA) products, the ‘MX-COM’ textual logo is being replaced by a ‘CML’

textual logo.

Company contact information is as below:

CML Microcircuits

(UK)Ltd

COMMUNICATION SEMICONDUCTORS

CML Microcircuits

COMMUNICATION SEMICONDUCTORS

CML Microcircuits

(Singapore)PteLtd

COMMUNICATION SEMICONDUCTORS

CML Microcircuits

(USA) Inc.

COMMUNICATION SEMICONDUCTORS

Oval Park, Langford, Maldon,

Essex, CM9 6WG, England

Tel: +44 (0)1621 875500

Fax: +44 (0)1621 875600

uk.sales@cmlmicro.com

www.cmlmicro.com

4800 Bethania Station Road,

Winston-Salem, NC 27105, USA

Tel: +1 336 744 5050,

0800 638 5577

Fax: +1 336 744 5054

us.sales@cmlmicro.com

www.cmlmicro.com

No 2 Kallang Pudding Road, 09-05/

06 Mactech Industrial Building,

Singapore 349307

Tel: +65 7450426

Fax: +65 7452917

sg.sales@cmlmicro.com

www.cmlmicro.com

D/CML (D)/2 May 2002