Cermetek Microelectronics, Inc.
CH1788 Surface Mount PLCC 2400bps Modem
2006 Cermetek Microelectronics, Inc.
Page 22
Document No. 607-0018 Revision A6 (01/06)
Table 8. CH1788 D.C. Electrical Specifications.
Parameter
Description
Min. Typ. Max. Units
V
CC
Positive Supply Voltage- Noise less than 50mV
5V
3.3V
4.75
2.70
5.0
3.30
5.3
3.60
V
Idd1
Nominal Operating Current
5V
3.3V
51 62
16
mA
Idd2
Power Down Idle mode Current
5V
3.3V
3.0
2.5
mA
Idd3
Power Down “Zero” Mode Current
5V
3.3V
15
10
uA
V
IH
High Level Input Voltage*
5V
3.3V
V
CC
/2
0.2 V
CC
+5.5
V
V
IL
Low Level Input Voltage*
5V
3.3V
.50
0.2 V
CC
V
I
IN
Input Leakage Current – All Pins
1
uA
V
OH
High Level @ -4mA 5V and 3.3V
V
CC
-.45
V
V
OL
Low Level @ 4mA
5V
3.3V
0.6
0.45
V
Test conditions: CH1788 VCC = 5V
±
10%, Temp = 0
°
C to 70
°
F.
CH1788-3 VCC = 3.3V
±
10%, Temp = 0
°
C to 70
°
F
*Output Load = 30 pF
±
one TTL.
Table 9. CH1788 Operational Specifications.
Parameter Minimum
Typical
Maximum
Units Comments
Off Hook Impedance
600
Ohms
Trans Hybrid Loss
25
dB
600 Ohm, RXA, TXA
Ring Voltage Loop
110V
250V
V
pp
On 48VDC line voltage offset
for sustained periods of
seconds.
Line Loop Current-(Off-
Hook)
20 80
mA
Return Loss @ 1000Hz
15
dB
600 Ohm
Ring Frequencies
10
20
75
Hz
Receiver Insertion Gain
-0.5
0.0
+0.5
dBm
600 Ohm- Data Mode
Transmit Power
-10.0
dBm
When recommended
initialization is used.
First Character After Reset
0.5
2.0
sec
Delay
Inter Character Delay
0
50
msec
Between all command
characters
Command Delay
125
150
msec
Between all AT commands
Minimum Reset Pulse
Duration
50
msec
If user supplied
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