Bell 202 Compatible Modem
FX614
Notes
Min.
Typ.
Max.
Units
Tx 5bits/sec (M1 = '1', M0 = '0').
Bit Rate
Mark (Logical '1') Frequency
Space (Logical '0') Frequency
0
385
-
5.0
-
0
5.1
389
-
Baud
Hz
Hz
6
Data and Mode Timing
Rx Data Delay (RXIN to RXD)
Tx Data Delay (TXD to TXOP)
Mode ZP to Tx or Rx
Mode Tx1200 to Rx1200
Mode Rx1200 to Tx1200
9
9
10
10
10
-
-
-
-
-
2.55
0.1
-
-
-
-
-
ms
ms
ms
ms
ms
20
4.0
0.2
Input Amplifier
Impedance (RXIN Pin)
Voltage Gain
7
7
10.0
-
-
-
-
MW
V/V
500
XTAL/CLOCK Input
'High' Pulse Width
'Low' Pulse Width
8
8
100
100
-
-
-
-
ns
ns
Notes: 1. At 25°C, not including any current drawn from the FX614 pins by external circuitry other than
X1, C1 and C2.
2. TXD, RXEQ and CLK inputs at VSS, M0 and M1 inputs at VDD
.
3. Measured at the Rx Input Amplifier output (pin RXFB) 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 1.6.1
4. Flat noise in 200 - 3200Hz band.
5. Relative to 775mVrms at VDD= 5.0V for load resistances greater than 40kW.
6. TXOP held at approximately VDD/2.
7. Open loop, small signal low frequency measurements.
8. Timing for an external input to the XTAL/CLOCK pin.
9. Assuming data retiming is not enabled.
10. Delay from mode change to reliable data at TXOP or RXD pins.
ã 1997 Consumer Microcircuits Limited
15
D/614/4
CMLMICRO [ CML MICROCIRCUITS ]
