FEDL7012-06-02
ML7012-06
AN EXAMPLE OF LEVEL DIAGRAM
1. Modem transmission, VDD 3 V
AOUT = -20dBm, RCAO = -20dBm, TXAN = -14dBm, TXAP = -14dBm, LINE = -16dBm
(S34 = 2dB(default), R5/R4 = 2, Loss at a transformer = 2dB)
2. DTMF Transmission, VDD 3 V DTMF high group level, DTMF low group level is approx. 1dB lower than
below.
AOUT = -14.5dBm, RCAO = -14.5dBm, TXAN = -8.5dBm, TXAP = -8.5dBm, LINE = -10.5dBm
(S35 = 0dB(default), R5/R4 = 2, Loss at a transformer = 2dB)
3. Modem transmission, VDD 2.7V
AOUT = -20dBm, RCAO = -20dBm, TXAN = -15.9dBm, TXAP = -15.9dBm, LINE = -17.9dBm
(S34 = 2dB(default), R5/R4 = 1.6, Loss at a transformer = 2dB)
4. DTMF Transmission, VDD 2.7V DTMF high group level, DTMF low group level is approx. 1dB lower than
below.
AOUT = -14.5dBm, RCAO = -14.5dBm, TXAN = -10.4dBm, TXAP = -10.4dBm, LINE = -12.4dBm
(S35 = 0dB(default), R5/R4 = 1.6, Loss at a transformer = 2dB)
5. Modem receive (max.)
LINE= -9dBm, at connection of R6 and R7 = -11dBm, GSR= -15dBm,
(R8/R7 = 0.63 = -4dB, Loss at a transformer = 2dB)
6. Modem receive (min.)
LINE= -40dBm, at connection of R6 and R7 = -42dBm, GSR= -46dBm,
(R8/R7 = 0.63 = -4dB, Loss at a transformer = 2dB)
CONNECTION OF CRYSTAL OSCILLATOR
Connect a 11.0592 MHz crystal and a 1 M feedback resistor between OSC0 and OSC1.
The values of capacitors C01 and C02 connected between OSC0 and GND, and OSC1 and GND vary with the load
capacitance of the crystal and the wiring capacitance of the board. Set the values by the crystal manufacture’s
matching evaluation.
If an external clock is used, input it to OSC0.
C01
15pF
11.0592 MHz
C02
15pF
OSC0
ROSC
1 M
OSC1
20/23