Data Sheet
4-Level FSK Modem Data Pump Page 42 of 47 MX919B PRELIMINARY INFORMATION
©2001 MX•COM, INC. www.mxcom.com Tele: 800 638 5577 336 744 5050 Fax: 336 744 5054 Doc. # 20480170.003
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA All trademarks and service marks are held by their respective companies.
6.1.3 Operating Characteristics
For the following conditions unless otherwise specified:
Xtal Frequency = 4.9152MHz, Symbol Rate = 4800 symbols/sec,
Noise Bandwidth = 0 to 9600Hz, V
DD
= 5.0V @ T
AMB
= 25°C
Notes Min. Typ. Max. Units
DC Parameters
I
DD
1 4.0 10.0 mA
I
DD
(V
DD
= 3.3V) 1 2.5 6.3 mA
I
DD
(Powersave Mode) 1 1.5 mA
I
DD
(Powersave Mode, V
DD
= 3.3V) 1 0.6 mA
AC Parameters
TX Output
TXOUT Impedance 2 1.0 2.5
kΩ
Signal Level
TXIMP = 0 3 0.8 1.0 1.2 V
P-P
TXIMP = 1 3 0.88 1.1 1.32 V
P-P
Output DC Offset with respect to V
DD
/2 4 -0.25 0.25 V
RX Input
RXIN Impedance (at 100Hz) 10.0
MΩ
RXIN Amp Voltage Gain (input = 1mV
RMS
at 100Hz) 300 V/V
Input Signal Level 5 0.7 1.0 1.3 V
P-P
DC Offset with respect to V
DD
/2 5 -0.5 0.5 V
XTAL/CLOCK INPUT
‘High’ Pulse Width 6 40 ns
‘Low’ Pulse Width 6 40 ns
Input Impedance (at 100Hz) 10.0
MΩ
Inverter Gain (input = 1mV
RMS
at 100Hz) 20 dB
µC Interface
Input Logic ‘1’ Level 7,8 70% V
DD
Input Logic ‘0’ Level 7,8 30% V
DD
Input Leakage Current (V
IN
= 0 to V
DD
) 7,8 -5.0 5.0 µA
Input Capacitance 7,8 10.0 pF
Output Logic ‘1’ Level (I
OH
= 120µA) 8 92% V
DD
Output Logic ‘0’ Level (I
OL
= 360µA) 8,9 8% V
DD
‘Off’ State Leakage Current (V
OUT
= V
DD
) 9 10 µA
6.1.3.1 Operating Characteristics Notes:
1. Not including any current drawn from the modem pins by external circuitry other than the Xtal oscillator.
2. Small signal impedance.
3. Measured after the external RC filter (R4/C5) for a "+3 +3 -3 -3...." symbol sequence, (Tx output level is
proportional to V
DD
).
4. Measured at the TXOUT pin with the modem in the Tx idle mode.
5. For optimum performance, measured at RXAMPOUT pin, for a "...+3 +3 -3 -3..." symbol sequence,
TXIMP = 0 or 1, The optimum level and DC offset values are proportional to V
DD
.
6. Timing for an external input to the XTAL/CLOCK pin.
7.
WR , RD , CS , A0 and A1 pins.
8. D0 - D7 pins.
9.
IRQ pin.