Datasheet
®
14
PCM3501
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
MSBMSB LSB LSB
MSBMSB LSB LSB
15 14 13 12 11 210543 151413 12 11
210543
15 14 13 12 11 210543 151413 12 11
210543
1/f
S
16-Bit/Frame
SYMBOL DESCRIPTION MIN TYP MAX UNITS
t
BCKP
BCK Period 2400 ns
t
BCKH
BCK Pulse Width HIGH 800 ns
t
BCKL
BCK Pulse Width LOW 800 ns
t
FSW
FS Pulse Width HIGH t
BCKP
– 60 t
BCKP
t
BCKP
+ 60 ns
t
FSP
FS Period 1/f
S
t
FSSU
FS Set Up Time to BCK Rising Edge 60 ns
t
FSHD
FS Hold Time to BCK Rising Edge 60 ns
t
DISU
DIN Set Up Time to BCK Rising Edge 60 ns
t
DIHD
DIN Hold Time to BCK Rising Edge 60 ns
t
CKDO
Delay Time BCK Falling Edge to DOUT 0 80 ns
t
R
Rising Time of All Signals 30 ns
t
F
Falling Time of All Signals 30 ns
FIGURE 6. Serial Interface Format.
FIGURE 7. Serial Interface Timing for Slave Mode.
t
FSW
t
FSSU
t
FSHD
t
BCKP
t
BCKH
t
DISU
t
DIHD
t
BCKL
t
CKDO
t
FSP
FS
(input)
BCK
(input)
DIN
(input)
DOUT
(output)
NOTES: Timing measurement reference level is (V
IH
/V
IL
)/2. RIsing and falling time is measured
from 10% to 90% of IN/OUT signal swing. Load capacitance of DOUT signal is 50pF.
0.5V
DD
0.5V
DD
0.5V
DD
0.5V
DD