Datasheet
73M1903 Data Sheet DS_1903_032
4 Rev. 2.1
1 Signal Description
The Teridian 73M1903 modem AFE IC is available in a 20-pin TSSOP or 32-pin QFN package with the
same pin out. The following table describes the function of each pin. There are two pairs of power
supply pins, VPA (analog) and VPD (digital). They should be decoupled separately from the supply
source in order to isolate digital noise from the analog circuits internal to the chip. Failure to adequately
isolate and decouple these supplies will compromise device performance.
Table 1: Inputs Selected in Regular and Alternate Multiplexer Cycles
Pin Name Type
32QFN
Pin #
20VT
Pin#
Description
VND GND 1,22 2,18 Negative Digital Ground
VNA GND 16 13 Negative Analog Ground
VPD PWR 2,25 3 Positive Digital Supply
VPA PWR 10 8 Positive Analog Supply
VPPLL PWR 20 17 Positive PLL Supply, shared with VPD
VNPLL PWR 17 14 Negative PLL Ground
RST
I 9 7
Master reset. When this pin is a logic 0 all registers are
reset to their default states; Weak-pulled high- default.
OSCIN I 19 16
Crystal oscillator input. When providing an external clock
source, drive OSCIN.
OSCOUT O 18 15 Crystal oscillator circuit output pin.
GPIO(0-7) I/O
3, 4, 5, 6,
23,
24,30,31
N/A
Software definable digital input/output pins. Not available in
the 20VT (TSSOP) package.
VREF O 13 6 Reference voltage pin (Reflects VREF).
RXAP I 15 12 Receive analog positive input.
RXAN I 14 11 Receive analog negative input.
TXAP O 12 10 Transmit analog positive output.
TXAN O 11 9 Transmit analog negative output.
SCLK O 8 5
Serial interface clock. With SCLK continuous selected,
Frequency = 256*Fs ( =2.4576 MHz for Fs=9.6 kHz)
SDOUT O 32 1 Serial data output (or input to the host).
SDIN I 29 20 Serial data input (or output from the host).
FS O 7 4 Frame synchronization. (Active Low)
TYPE I 27
19 Type of frame sync. Open, weak-pulled high = early
(mode1); tied low = late (mode0).
SckMode I 28 NA
Controls the SCLK behavior after FS. Open, weak-pulled
high = SCLK Continuous; tied low = 32 clocks per R/W
cycle. Not available in 20VT.