ICM7102B
LOW COST SINGLE CHIP TELEPHONE IC
Oscillator Input
3.58MHz ceramic resonator input.
Oscillator Output
3.58MHz clock output. Can be used to drive other few high impedance inputs.
Ring Detection Input
11
12
OSC1
OSC2
Input for ring frequency detection. Active when HS_DPB=LOW. When pulses
with frequency between 13Hz and 70Hz are detected on this pin, ring melody
is generated on the MO pin.
13
14
RGD
MO
Melody Output
Open drain output. When ring signal is detected on the RGD pin, ring melody
pulses are generated on this pin.
Keypad Columns
15
16
17
18
C4B
C3B
C2B
C1B
Keypad column inputs. When a column input pin is shorted to a row output
pin, appropriate DTMF signal is generated. This DTMF signal complies with
CCITT recommendation. For example, when R1 and C1B are shorted (when
button #1 is pressed), DTMF signal of frequency 697Hz + 1209Hz is
generated and transmitted thru TXO pin.
19
20
21
22
R4
R3
R2
R1
Keypad Rows
Keypad rows. Logic pulses are generated on these pins to scan user input. See
also Keypad Column pins. During powerꢀonꢀreset, these pins are also used to
determine various dialing modes. See description on Dialing Function section.
Microphone Inputs
23
24
M1
M2
Input for electret microphone. M1 connects to inverting input of internal
differential amplifier via a resistor. M2 connects to the nonꢀinverting input via
a resistor.
Complex Impedance and AC Impedance Input
Placing resistor between CI and AGND pins adjusts the AC impedance. If CI
pin is left floating the typical AC impedance is 1000 ohm (when current sense
resistor (R11) is 30 ohm).
Received Audio Amplifier Output
Received audio amplifier output. RXO can drive a typical 120ꢀohm dynamic
earpiece speaker.
25
26
27
28
CI
RXO
RXI
STB
Received Audio Amplifier Input
Nonꢀinverting input for internal received audio differential amplifier. RXI
connects to the amplifier via an internal resistor. RXI also internally connects
to the feedback path of the circuitry that determines the AC impedance.
Side Tone Balance Input
Inverting input for internal received audio differential amplifier. STB connects
to the amplifier via an internal resistor.
Rev. 2.7
ICmic reserves the right to change the specifications without prior notice
3
ICMIC [ IC MICROSYSTEMS ]
