Specifications

AN93
Rev. 0.8 79
U65 (DAAC4)
U65 (DAAC4) is a bit-mapped register with bits 3:0 and
12:5 reserved. Bits 1:0 and 6:5 must not be changed in
a read-modify-write cycle.
Bit 14 (PWMG) = 0 (default) provides 0 dB gain to
AOUT. PWMG = 1 provides a 6 dB gain to AOUT.
Bit 13 (PDN) = 0 allows the device to operate at normal
power level. PDN = 1 completely powers down both the
Si3018/10 and the Si2493/57/34/15/04 chips. The bit
takes effect at the carriage return of the AT command
writing this bit to a 1. Once this bit is set, the modem
must be reset via the RESET
pin (Si2493/57/34/15/04,
pin 12) to become active. When reset, the modem
reverts to the default settings.
Bit 4 (PDL) = 0 (default) allows the modem to operate at
normal power levels. PDL = 1 powers down the Si3018/
103018/10. This is a test mode typically used for board-
level debugging, not normal modem operation.
U65 resets to 0x00E0 with a power-on or manual reset.
Table 51. U63 Bit Map
Bit Name Function
15:8 LCS Off-hook loop current (1.1 mA/bit).
7:4 ACT AC Termination Select.
ACT AC Termination
0000 Real 600 Ω
0011 220 Ω + (820 Ω || 120 nF) and 220 Ω + (820 Ω || 115 nF)
0100 370 Ω + (620 Ω || 310 nF)
1111 Global complex impedance
3:0 Reserved Read returns 0x0003.
Table 52. U65 Bit Map
Bit Name Function
15 Reserved Read returns zero.
14 PWMG PWM Gain.
0 = No gain.
1 = 6 dB gain applied to AOUT.
13 PDN Powerdown.
0 = Normal.
1 = Powerdown.
12:7 Reserved Read returns zero.
6:5 Reserved Must not change in a read-modify-write.
4PDLPowerdown Line-Side Chip.
0 = Normal operation.
1 = Places the Si3018/10 in powerdown mode.
3:2 Reserved Read returns zero.
1:0 Reserved Must not change in a read-modify-write.