PCM3501 Datasheet, PDF (14/24 Pages) Burr-Brown (TI) – Low Voltage, Low Power, 16-Bit, Mono VOICE/MODEM CODEC

SERIAL INTERFACE
The serial interface of the PCM3501 is a 4-wire synchronous
serial port. It includes FS (pin 9), BCK (pin 8), DIN (pin 10)
and DOUT (pin 11). FS is the frame synchronization clock,
BCK is the serial bit or shift clock, DIN is the serial data input
for the DAC, and DOUT is the serial data output for the ADC.
The frame sync, FS, operates at the sampling frequency (f_S).
The bit clock, BCK, operates at 16f_S for normal operation.
DIN and DOUT also operate at the bit clock rate. Both FS
and BCK must be synchronous with the system clock (guar-
anteed in Master Mode). Data for DIN is clocked into the
serial interface on the rising edge of BCK, while data for
DOUT is clocked out of the serial interface on the falling
edge of BCK.
Figure 6 shows the serial interface format for the PCM3501.
The serial data for DIN and DOUT must be in Binary Two’s
Complement, MSB-first format. Figures 7 and 8 show the
timing specifications for the serial interface when used in
Slave and Master Modes.
FS
BCK
DIN
DOUT
15 14 13 12 11
MSB
5 4 3 2 1 0 15 14 13 12 11
LSB MSB
15 14 13 12 11
5 4 3 2 1 0 15 14 13 12 11
MSB
1/f_S
16-Bit/Frame
LSB MSB
FIGURE 6. Serial Interface Format.
543 210
LSB
543 210
LSB
FS
(input)
BCK
(input)
t_FSW
t_FSSU
t_FSHD
t_FSP
t_BCKP
t_BCKH
t_BCKL
0.5V_DD
0.5V_DD
DIN
(input)
t_DISU
t_DIHD
0.5V_DD
DOUT
(output)
t_CKDO
0.5V_DD
NOTES: Timing measurement reference level is (VIH/VIL)/2. RIsing and falling time is measured
from 10% to 90% of IN/OUT signal swing. Load capacitance of DOUT signal is 50pF.
SYMBOL DESCRIPTION
MIN
t_BCKP
t_BCKH
t_BCKL
t_FSW
t_FSP
t_FSSU
t_FSHD
t_DISU
t_DIHD
t_CKDO
t_R
t_F
BCK Period
BCK Pulse Width HIGH
BCK Pulse Width LOW
FS Pulse Width HIGH
FS Period
FS Set Up Time to BCK Rising Edge
FS Hold Time to BCK Rising Edge
DIN Set Up Time to BCK Rising Edge
DIN Hold Time to BCK Rising Edge
Delay Time BCK Falling Edge to DOUT
Rising Time of All Signals
Falling Time of All Signals
2400
800
800
t_BCKP – 60
60
60
60
60
0
TYP
t_BCKP
1/f_S
MAX UNITS
ns
ns
ns
t_BCKP + 60 ns
ns
ns
ns
ns
80
ns
30
ns
30
ns
FIGURE 7. Serial Interface Timing for Slave Mode.
®
PCM3501
14